Surgeons
36 years of experience
Video profile
Accepting new patients
Southfield
Michigan Orthopaedic Institute
26025 Lahser Rd
Fl 2
Southfield, MI 48033
248-663-1900
Locations and availability (5)

Education ?

Medical School Score
Wayne State University (1974)
  • Currently 1 of 4 apples

Awards & Distinctions ?

Awards  
One of America's Leading Experts on:
Diskectomy
Spinal Diseases
Spinal Fusion
Spinal Osteophytosis
Spinal Stenosis
Spondylolisthesis
U.S. News Top Doctors (2011)
Detroit Hour Magazine's Top Docs (2010)
Hour Detroit Magazine's Top Docs (2010)
Becker's Orthopedic and Spine Review, 100 Best Spine Surgeons in America (2011), Hour Detroit Magazine's Top Docs (2010), Outstanding Academic Excellence Award, Beaumont Health System (2011), U.S. News Top Doctors (2011)
Becker's Orthopedic and Spine Review, 100 Best Spine Surgeons in America, 2011, Detroit Hour Magazine's Top Docs (2010)
Outstanding Academic Excellence Award, Beaumont Health System (2011)
Becker's Orthopedic and Spine Review, 100 Best Spine Surgeons in America (2011)
Patients' Choice Award (2008)
Associations
American Board of Orthopaedic Surgery
Depuymitek.com (back and Neck Pain)- (allaboutbackandneckpain.com)
Cervical Spine Research Society

Affiliations ?

Dr. Herkowitz is affiliated with 6 hospitals.

Hospital Affilations

Score

Rankings

  • Beaumont Hospital,Troy
    Orthopaedic Surgery
    44201 Dequindre Rd, Troy, MI 48085
    • Currently 3 of 4 crosses
    Top 50%
  • Beaumont Hospital, Grosse Pointe
    Orthopaedic Surgery
    468 Cadieux Rd, Grosse Pointe, MI 48230
    • Currently 3 of 4 crosses
    Top 50%
  • Beaumont Hospital, Royal Oak *
    Orthopaedic Surgery
    3601 W 13 Mile Rd, Royal Oak, MI 48073
    • Currently 2 of 4 crosses
  • Royal Oak 31 Years
  • Beaumont Affiliation & Years on StaffRoyal Oak
  • Royal Oak
  • * This information was reported to Vitals by the doctor or doctor's office.

    Publications & Research

    Dr. Herkowitz has contributed to 81 publications.
    Title Distractive Force Relative to Initial Graft Compression in an in Vivo Anterior Cervical Discectomy and Fusion Model.
    Date May 2010
    Journal Spine
    Excerpt

    An in vivo biomechanical anterior cervical discectomy and instrumented fusion (ACDFI) model employing a calibrated distractor and a subminiature load cell used to intraoperatively measure distractive force across the discectomy site and subsequent compressive force across the interbody load cell following distractor removal.

    Title Debating the Value of Spine Surgery.
    Date May 2010
    Journal The Journal of Bone and Joint Surgery. American Volume
    Excerpt

    Lumbar arthrodesis is a commonly performed operative procedure for the treatment of low back pain. Recently, total disc arthroplasty has gained some acceptance among surgeons and patients. However, the indications for and results of back pain surgery remain controversial and confusing. Available information suggests that meaningful functional improvement from these procedures is debatable and that the cost of such elective operations is high. Currently, lumbar disc replacement has gained minimal support from governmental and private payers. Among those attending this symposium at the 2009 Annual Meeting of the AOA, the vast majority concurred that Medicare and private insurance should not necessarily pay for disc replacement surgery. Interestingly, among this skeptical group of orthopaedic surgeons, only 23% believed that degeneration of the intervertebral disc is the major cause of low back pain. When asked the hypothetical question, "If you experienced chronic low back pain with degenerative changes at one level, what course of treatment would you opt for?" 61% responded that they would choose nonoperative treatment and 38%, that they would choose no treatment. Of more than 100 respondents, only one responded that he or she would undergo fusion and one admitted a willingness to undergo disc replacement in this hypothetical scenario.

    Title Biomechanical Evaluation of the Kinematics of the Cadaver Lumbar Spine Following Disc Replacement with the Prodisc-l Prosthesis.
    Date March 2010
    Journal Spine
    Excerpt

    Biomechanical study of the ProDisc-L in a cadaveric model under pure moment loading. OBJECTIVE.: To determine the kinematic properties of a lumbar spine motion segment and the adjacent level following ProDisc-L disc replacement in the cadaveric spine.

    Title The Mentoring and Education of Spine Physicians: the Issls Mission.
    Date September 2008
    Journal Spine
    Title Effects of Disc Height and Distractive Forces on Graft Compression in an Anterior Cervical Corpectomy Model.
    Date July 2008
    Journal Spine
    Excerpt

    STUDY DESIGN: An in vitro biomechanical study using a calibrated distractor and a subminiature load cell in a cadaveric cervical corpectomy construct. OBJECTIVE: To study the inter-relationships of defect height, graft height, and compressive and distractive forces in an anterior cervical corpectomy model. SUMMARY OF BACKGROUND DATA: The effects of graft size on compressive and distractive forces in cervical corpectomy remain unknown. Larger grafts afford neural decompression through anterior column distraction, but may subject the graft and vertebral bodies to excessive loads, increasing graft fracture, and subsidence risk. METHODS: The intended corpectomy defect was measured radiographically in 17 specimens. A C6 corpectomy was performed and the specimens embedded in polyester resin. A distractive force was applied through a strain gauge fitted distractor to allow introduction of allograft struts fixed to a subminiature load cell. After distraction was removed, immediate compressive force was measured. The specimen was then placed in a loading frame to simulate head weight. RESULTS: Distractive forces of 36.65, 70.90, and 118.10 N were required to insert 23, 25, and 27 mm grafts, respectively. On removal of this distraction, immediate compressive loads of 2.87, 4.74, and 8.95 N were noted. No statistically significant relationship between the intended corpectomy height and graft distraction forces was found. A statistically significant relationship was observed between distractive force required for graft insertion and immediate graft compressive force. Distractive force was also significantly related to the compressive force borne by the loaded strut graft. CONCLUSION: Significantly higher distractive and compressive forces were recorded with larger grafts. Intended corpectomy height was not an accurate predictor of graft loads.

    Title Pain Management: the Orthopaedic Surgeon's Perspective.
    Date December 2007
    Journal The Journal of Bone and Joint Surgery. American Volume
    Title Early Failure of Bioabsorbable Anterior Cervical Fusion Plates: Case Report and Failure Analysis.
    Date July 2007
    Journal Journal of Spinal Disorders & Techniques
    Excerpt

    STUDY DESIGN: Case report with forensic failure analysis. OBJECTIVE: To determine the failure modes of 3 explanted 70:30 PLDLA Mystique (Medtronic Sofamor Danek, Memphis, TN) graft containment plates retrieved from revision surgery for early device failure. SUMMARY OF BACKGROUND DATA: To reduce the problems of stress-shielding and radiopacity associated with metallic systems, bioabsorbable polymers have been used in anterior cervical discectomy and fusion procedures. Degradation of mechanical properties in vivo is a major concern when using bioabsorbable systems. Three of 6 patients who underwent anterior cervical discectomy with instrumented fusion, using Mystique graft containment systems experienced early failure requiring revision to alternate hardware. METHODS: Devices were retrieved after failure and analyzed by light microscopy and environmental scanning electron microscopy. Simulations were performed with an unused plating system to induce damage for comparison with the retrieved devices. A detailed case review was performed to identify possible sources of extraordinary loading or damage. RESULTS: One plating system failed at 6 weeks postimplantation due to fatigue fracture of the screws. Crack initiation sites were identified at the interface of the thread root and mold line of the screw. Another plating system failed at 16 weeks postimplantation due to the coalescence of radial microcracking between holes in the plate, leading to catastrophic failure of the plate. The final plating system failed during the implantation surgery, when the screw fractured in torsion. CONCLUSIONS: Stress concentrations at the screw head-shaft interface and thread-shaft interface reduce the fatigue performance of bioabsorbable screws. Hydrolysis of the polymer may also play a role in the reduction of resistance to crack initiation and propagation.

    Title Effect of Polyethylene Pretreatments on the Biomimetic Deposition and Adhesion of Calcium Phosphate Films.
    Date June 2007
    Journal Acta Biomaterialia
    Excerpt

    The effect of ultraviolet irradiation and glow discharge (GD) processing of the polyethylene (PE) substrates on deposition of calcium phosphate (CaP) films from supersaturated aqueous calcium phosphate solutions was investigated in this study. CaP coatings deposited on the PE substrates were comprised of elongated clusters of spherical particles and 100% of the free surface area of nearly all of the substrates was covered with a porous CaP film after a 3 day immersion. Nano-scratch tests determined that PE-CaP adhesion was most improved when PE substrates were subjected to 50W GD treatments. As determined by contact angle measurements, the GD-treated PE samples had the highest electron donor parameter of surface energy, suggesting that enhancing the electron donor parameter of PE leads to improved adhesion with the biomimetic CaP coating.

    Title American Board of Orthopedic Surgery (abos) Part Ii Oral Examination.
    Date October 2006
    Journal Spine
    Title Comparison of Op-1 Putty (rhbmp-7) to Iliac Crest Autograft for Posterolateral Lumbar Arthrodesis: a Minimum 2-year Follow-up Pilot Study.
    Date June 2006
    Journal Spine
    Excerpt

    STUDY DESIGN: A prospective, randomized, controlled, multicenter clinical study. OBJECTIVE: To compare the safety and clinical and radiographic outcomes of OP-1 (BMP-7) Putty to autogenous iliac crest bone graft in a population of patients undergoing laminectomy and posterolateral fusion for symptomatic lumbar stenosis associated with degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Although the existing preclinical and clinical data suggest that OP-1 is able to achieve osteoinduction and clinical fusion in a variety of situations, the efficacy of this recombinant protein in a clinical spine fusion population has not been fully elucidated. This study directly compares the efficacy and safety of OP-1 putty to autograft bone for arthrodesis in patients with symptomatic stenosis in association with degenerative spondylolisthesis. METHODS: Thirty-six patients with degenerative lumbar spondylolisthesis and symptoms of neurogenic claudication underwent laminectomy, bilateral medial facetectomy, and posterolateral fusion using either iliac crest autograft or OP-1 Putty. Oswestry scores and SF-36 questionnaires were used to determine the clinical response to treatment. Independent, blinded neuroradiologists reviewed both static and dynamic radiographs to determine the fusion status. Successful fusion was declared whenthe presence of continuous bridging bone between the transverse processes was observed and less than 5 degrees of angular motion and 2 mm of translational movement was measured using digital calipers. RESULTS: Efficacy data were tabulated for 27 patients at the 24-month time point and an additional 4 patients (without evaluable 24-month results) at the 36-month time point. One patient was not evaluable for radiology, so the data reflect clinical information for 31 patients and radiology for 30 patients. Clinical success, defined as a 20% improvement in the preoperative Oswestry score, was achieved by 17 of 20 (85%) OP-1 Putty patients and 7 of 11 (64%) autograft patients. A successful posterolateral fusion was achieved in 11 of 20 (55%) OP-1 Putty patients and 4 of 10 (40%) autograft patients. SF-36 scores showed similar clinical improvement in both groups. No systemic toxicity, ectopic bone formation, recurrent stenosis, or other adverse events specifically related to the use of the OP-1 Putty implant were observed. CONCLUSION: This study represents the first clinical trial to demonstrate the safety and similarity of OP-1 Putty as a replacement for autogenous bone graft in the posterolateral fusion environment with a minimum of 2-year follow-up. OP-1 Putty was able to achieve osteoinduction leading to a radiographically solid fusion in the absence of autogenous iliac crest bone graft in 55% of the patients at 24 and 36 months. These results compare favorably to the historical fusion rates reported for uninstrumented arthrodesis in this challenging clinical scenario.

    Title Total Disc Replacement with the Charite Artificial Disc Was As Effective As Lumbar Interbody Fusion.
    Date June 2006
    Journal The Journal of Bone and Joint Surgery. American Volume
    Title Outcome of Local Bone Versus Autogenous Iliac Crest Bone Graft in the Instrumented Posterolateral Fusion of the Lumbar Spine.
    Date May 2006
    Journal Spine
    Excerpt

    STUDY DESIGN: Retrospective, comparative study of clinical and radiologic outcome with independent, blinded observer. OBJECTIVES: To compare the clinical and radiologic outcome of instrumented posterolateral lumbar fusion using local bone versus autogenous iliac crest bone graft (ICBG). SUMMARY OF BACKGROUND DATA: There is no published report of outcome of posterolateral spinal fusion using local bone alone for degenerative disorders of the lumbar spine. MATERIALS AND METHODS: Seventy-six cases (male 26, female 50) of spinal stenosis, operated during 1996 and 1997 by the senior author, were reviewed. All the cases had decompression and posterior spinal fusion with pedicle screw instrumentation. Forty cases had only local bone graft obtained from decompression, morselized in a bone mill, and 36 cases had autogenous ICBG. Mean age was 60 years (range, 27-83 years). Fusion was performed at one level in 51 (67%), two levels in 16 (21%), three levels in 5 (7%), and four or more levels in 4 cases (5%). Minimum follow-up was 2-years (mean, 28 years; range, 24-72 months). An independent, blinded radiologist rated plain radiographs as fused, indeterminate, or nonunion. RESULTS: There was no difference in age, sex, and diagnosis between the two groups. Overall fusion rate was higher in the ICBG group (75%, 27 of 36) compared with the local bone group (65%, 26 of 40) but not significantly different (P = 0.391). Analyzed separately according to the number of fusion levels, the local bone group achieved similar fusion rate ( approximately 80%) in single-level fusion but a much smaller fusion rate in multilevel fusion (20% vs. 66%, P = 0.029) compared with the ICBG group. Mean improvement in the Oswestry Disability Inventory was 36% in the local bone group and 32% in the ICBG group. There was no significant difference in overall clinical outcome between the two groups. There was no correlation between fusion status and clinical outcome. Blood loss and hospital stay were significantly less in the local bone group; however, blood losswas more significantly related to the sum total number of segments undergoing decompression and fusion. CONCLUSIONS: Use of local bone graft alone achieved a similar fusion rate in single-level fusion but a much smaller fusion rate in multilevel fusion compared with the ICBG group. Local bone graft alone achieved a similar clinical outcome but less morbidity irrespective of number of fusion level.

    Title Spine Fellowship Education and Its Association with the Part-ii Oral Certification Examination.
    Date April 2006
    Journal The Journal of Bone and Joint Surgery. American Volume
    Title Treatment of Instability and Spondylolisthesis: Surgical Versus Nonsurgical Treatment.
    Date March 2006
    Journal Clinical Orthopaedics and Related Research
    Excerpt

    Spondylolisthesis is a common cause of lower-back pain, radiculopathy, and neurogenic claudication among the adult population. Treatment should begin with nonoperative measures that may include physical therapy, aerobic exercise, epidural steroid injections, and homeopathic remedies. If these treatments fail, surgical intervention may provide the patient pain relief and improvement in neurologic symptoms. The use of instrumentation for posterolateral fusions as well as interbody fusion may improve clinical outcomes for those having surgical intervention. We discuss the current nonoperative modalities and surgical techniques treating degenerative spondylolisthesis. LEVEL OF EVIDENCE: Level V: Expert Opinion. See the Guidelines for Authors for a complete description of the levels of evidence.

    Title Degenerative Spondylolisthesis: Review of Current Trends and Controversies.
    Date February 2006
    Journal Spine
    Excerpt

    STUDY DESIGN: A literature-based review. OBJECTIVES: To review management and controversies and to present authors recommendations. SUMMARY OF BACKGROUND DATA: There is considerable controversy regarding indication for surgery, role for decompression alone, and decompression with fusion with or without instrumentation. METHODS: Review of English language medical literature. RESULTS: The condition may stabilize itself with the collapse of the disc spaces and osteophytes but may continue to progress in nearly a third of the cases. It may cause predominantly back pain due to segmental instability, or radicular pain/neurogenic claudication secondary to root entrapment or spinal stenosis. When conservative treatment fails, the mainstay of surgical treatment is decompressive laminectomy and fusion, with or without instrumentation. CONCLUSIONS: Decompression primarily relieves radicular symptoms and neurogenic claudication whereas fusion primarily relieves back pain by elimination of instability. The goals for instrumentation are to promote fusion and to correct deformity. Fusion has a better long-term outcome than decompression alone. There is evidence that instrumentation improves fusion rate but does not improve clinical outcome in a relatively short-term follow-up. However, outcome of pseudarthrosis cases deteriorates over time and solid fusion produces better long-term outcome. The benefit of instrumentation comes with a price of higher postoperative morbidity and complication rate. Bone morphogenetic proteins are being tried to increase the rate of fusion, without increasing the complication rate, but the cost is prohibitive. More recently, dynamic stabilization with instrumentation but without fusion has been introduced as an alternative treatment. The current trends of surgical treatment and controversies are discussed.

    Title A Pilot Study Evaluating the Safety and Efficacy of Op-1 Putty (rhbmp-7) As a Replacement for Iliac Crest Autograft in Posterolateral Lumbar Arthrodesis for Degenerative Spondylolisthesis.
    Date February 2006
    Journal Spine
    Excerpt

    STUDY DESIGN: A prospective, randomized, controlled, multicenter clinical study was conducted. OBJECTIVE: To compare the clinical and radiographic outcomes of patients treated with OP-1 (BMP-7) Putty to autogenous iliac crest bone graft for one-level uninstrumented posterolateral fusion of the lumbar spine following decompressive laminectomy for the treatment of symptomatic degenerative spondylolisthesis with spinal stenosis. BACKGROUND: Preclinical studies have demonstrated that osteoinductive recombinant human osteogenic protein 1 in the form of OP-1 Putty is successful at achieving a posterolateral fusion in rabbits and dogs without any significant safety concerns. METHODS: Thirty-six patients with degenerative lumbar spondylolisthesis and symptoms of neurogenic claudication were randomized (2:1) to either OP-1 Putty (3.5 mg of OP-1 per side) or autogenous iliac crest bone graft for one-level uninstrumented posterolateral fusion following a decompressive laminectomy. Enrollment in the study was complete when 24 OP-1 Putty patients and 12 autograft patients had been randomized and treated. A patient administered Oswestry scale and SF-36 scale were used to determine clinical outcomes. Independent, blinded neuroradiologists reviewed both static and dynamic radiographs to determine fusion status. RESULTS: At the 1-year follow-up, 32 patients were available for clinical analysis and 29 patients were available for radiographic review. Clinical success as measured on the Oswestry scale was achieved by 18 of 21 (86%) OP-1 Putty patients and 8 of 11 (73%) autograft patients. SF-36 pain index scores showed similar results. Fourteen of 19 (74%) OP-1 Putty patients and 6 of 10 (60%) autograft patients achieved a successful posterolateral fusion fulfilling all fusion criteria. Of the 29 evaluable patients, 15 were both clinical and radiographic successes, 5 were radiographic successes but were clinical failures, 1 patient was both a radiographic and clinical failure, and 8 patients were radiographic failures but were clinical successes. No systemic toxicity, ectopic bone formation, recurrent stenosis, or other adverse events related to the OP-1 Putty implant were observed. CONCLUSION: Although the posterolateral spine is a challenging fusion environment in patients with degenerative spondylolisthesis, successful radiographic fusion was obtained using OP-1 Putty at a rate that was similar to autograft given the number of patients in this study. Importantly, there were no apparent adverse consequences related to the use of the OP-1 Putty implant in this patient population.

    Title Development and Calibration of a Load Sensing Cervical Distractor Capable of Withstanding Autoclave Sterilization.
    Date July 2005
    Journal Medical Engineering & Physics
    Excerpt

    In surgery of the cervical spine, a Caspar pin distractor is often used to apply a tensile load to the spine in order to open up the disc space. This is often done in order to place a graft or other interbody fusion device in the spine. Ideally a tight interference fit is achieved. If the spine is over distracted, allowing for a large graft, there is an increased risk of subsidence into the endplate. If there is too little distraction, there is an increased risk of graft dislodgement or pseudoarthrosis. Generally, graft height is selected from preoperative measurements and observed distraction without knowing the intraoperative compressive load. This device was designed to give the surgeon an assessment of this applied load. Instrumentation of the device involved the application of strain gauges and the selection of materials that would survive standard autoclave sterilization. The device was calibrated, sterilized and once again calibrated to demonstrate its suitability for surgical use. Results demonstrate excellent linearity in the calibration, and no difference was detected in the pre- and post-sterilization calibrations.

    Title Lumbar Spinal Stenosis: Indications for Arthrodesis and Spinal Instrumentation.
    Date June 2005
    Journal Instructional Course Lectures
    Excerpt

    Surgical indications for simple decompression in patients with lumbar spinal stenosis are well established. Following these guidelines, surgeons can expect good and excellent outcomes in 75% to 90% of patients. Despite the publication of many studies pertaining to the addition of arthrodesis and instrumentation, the indications for adding these procedures to a decompression are much less clear. Preoperative and intraoperative factors must be carefully considered when contemplating the addition of arthrodesis in the setting of spinal stenosis. In patients with preoperative degenerative spondylolisthesis, scoliosis, or kyphosis, and those in whom stenosis develops at a previously decompressed segment, serious consideration should be givenfor inclusion of an arthrodesis. Fusion should also be considered for those patients with stenosis adjacent to a previously fused lumbar segment. Excision of a significant portion of the facet joints or radical excision of the intervertebral disk during the course of the decompression predispose the patient to postoperative instability. The addition of an arthrodesis will likely benefit these patients. Relative indications for the use of spinal instrumentation in the setting of spinal stenosis include correction of deformity, recurrent spinal stenosis with instability, degenerative spondylolisthesis, adjacent segment stenosis with instability, and multiple level fusions.

    Title Failure of Human Cervical Endplates: a Cadaveric Experimental Model.
    Date October 2004
    Journal Spine
    Excerpt

    STUDY DESIGN: An in vitro biomechanical study using a servohydraulic testing machine on cadaveric endplates. OBJECTIVES: To characterize the effects of bone mineral density, endplate geometry, and preparation technique on endplate failure load. SUMMARY OF BACKGROUND DATA: The effects of endplate preparation methods on failure loads are only partly characterized in the literature. Endplate burring has been recommended to increase fusion rates. However, graft subsidence may complicate anterior reconstruction procedures. METHODS: After radiographic screening, 21 cadaveric cervical spines underwent dual-energy x-ray absorptiometry scanning to quantify mineral content. Endplate geometry was calculated in 55 randomly selected endplates from the inferior C2 to the superior T1 levels. These vertebrae were embedded in polyester resin and randomly left intact, perforated, or burred. The cervical endplates were loaded at a rate of 0.2 mm/s on an Instron materials tester with an attached 9 mm diameter polycarbonate rod (an area of 64 mm2). A stepwise, univariate linear regression was used to compare the point of endplate failure with the vertebral level, endplate area, gender, age, bone mineral density, and preparation technique. RESULTS: Mean bone mineral density, as measured by dual-energy x-ray absorptiometry, was 0.713 g/cm2 (+/- 0.173 g/cm2). Mean endplate area was calculated at 323 mm2. A mean compressive force of 754 N (+/- 445 N) was required before endplate failure. Trends toward increasing compressive loads were noted with decreasing endplate area and increasing bone mineral density. Increasing age (P = 0.0203), caudal vertebral level (P < 0.0001), endplate burring (P = 0.0068), and female gender (P = 0.0452) were associated with significantly lower endplate fracture loads in compression. CONCLUSIONS: Bone quality was predictive of endplate compressive failure loads. Intact endplates failed at significantly higher loads than their perforated or burred counterparts.

    Title Single Versus Multiple Dose Antibiotic Prophylaxis in Lumbar Disc Surgery.
    Date October 2004
    Journal Spine
    Excerpt

    STUDY DESIGN: Retrospective review. OBJECTIVES: To determine the efficacy of preoperative antibiotics alone in preventing wound infections following lumbar diskectomy. SUMMARY OF BACKGROUND DATA: It is well documented that antibiotics given perioperatively reduce the rate of postoperative wound infections in lumbar disc surgery. At our institution, the current protocol for patients undergoing lumbar diskectomy is a single preoperative antibiotic dose. This study was conducted to compare the rate of postoperative wound infection incurred for single versus multiple perioperative antibiotic doses. It was hypothesized that no significant difference in infection rates would be identified. METHODS: This retrospective chart review compared the rates of postoperative wound infections incurred when single versus multiple perioperative antibiotic doses were given to patients having lumbar laminotomy for herniated discs. The procedures were performed between 1993 and March 1999. There were 434 patients in the multiple dose group and 201 in the single dose group. The multiple dose group received one preoperative and at least three postoperative doses of antibiotics. The single dose group received one preoperative dose of antibiotics. A postoperative infection was deemed present by either clinical diagnosis or culture results. The medical records were reviewed for 6 weeks after surgery for all patients. RESULTS:There were 5 out of 435 (1.15%) infections in the multiple dose group and 3 out of 201 (1.49%) in the single dose group. Statistical analysis showed no significant difference between the two study groups. CONCLUSION: These results support the use of single preoperative dose of antibiotics in lumbar disc surgery. This is relevant as many lumbar diskectomy patients are candidates for early hospital discharge. At our institution, no increased risk of infection occurred for the single dose group.

    Title Degenerative Lumbar Spondylolisthesis with Spinal Stenosis: a Prospective Long-term Study Comparing Fusion and Pseudarthrosis.
    Date May 2004
    Journal Spine
    Excerpt

    STUDY DESIGN: A prospective, randomized study on patients who underwent posterior lumbar decompression with bilateral posterolateral arthrodesis. OBJECTIVE: To determine the long-term influence of pseudarthrosis on the clinical outcome of patients with degenerative spondylolisthesis and spinal stenosis. SUMMARY OF BACKGROUND DATA: Spinal decompression and posterolateral arthrodesis have been shown to be beneficial in the surgical treatment of symptomatic spinal stenosis with concurrent spondylolisthesis. METHODS: Forty-seven patients with single-level symptomatic spinal stenosis and spondylolisthesis were prospectively studied. Patients were treated with posterior decompression and bilateral posterolateral arthrodesis with autogenous bone graft. Radiographic evaluation was used to determine if fusion or pseudarthrosis was present. The solid fusion and pseudarthrosis groups were analyzed clinically, roentgenographically, and with a validated self-administered spinal stenosis questionnaire. RESULTS: Forty-seven patients were available for review at a range of follow-up from 5 to 14 years. Average follow-up was 7 years 8 months. Clinical outcome was excellent to good in 86% of patients with a solid arthrodesis and in 56% of patients with a pseudarthrosis (P = 0.01). Significant differences in residual back and lower limb pain was discovered between the two groups using a scale ranging from 0 (no pain) to 5 (severe pain). Preoperative back and lower limb pain scores were statistically similar between the two groups. The solid fusion group performed significantly better in the symptom severity and physical function categories on the self-administered questionnaire. The two groups had similar results in the patient satisfaction category of this questionnaire. CONCLUSIONS: In patients undergoing single-level decompression and posterolateral arthrodesis for spinal stenosis and concurrent spondylolisthesis, a solid fusion improves long-term clinical results. Benefits of a successful arthrodesis over pseudarthrosis were demonstrated with respect to back and lower limb symptomatology compared with prior shorter-term studies, which indicated no significant difference in clinical outcome between the two groups.

    Title Effects of a Cervical Compression Plate on Graft Forces in an Anterior Cervical Discectomy Model.
    Date February 2004
    Journal Spine
    Excerpt

    STUDY DESIGN: An ex vivo biomechanical study using an instrumented distractor and load cells in a cadaveric multilevel discectomy construct was conducted. OBJECTIVE: To demonstrate that a dynamic cervical plate can be used to increase compressive load on interbody grafts in a multilevel discectomy specimen. SUMMARY OF BACKGROUND DATA: Cervical plating is used to decrease pseudarthrosis, graft extrusion, and graft subsidence in multilevel anterior discectomy procedures. Plating may shield a graft as it resorbs and may reverse normal loading mechanics. METHODS: Preoperative disc height was measured in five cadaveric spines. A three-level discectomy was performed. The disc spaces were opened with a distractor instrumented with strain gauges to allow the introduction of spacers fixed rigidly to subminiature load cells. Distraction was removed, and immediate compressive forces were measured by the load cells. An external compressor was applied followed by a cervical plate. The specimen then was placed in a loading frame, and final compressive forces were measured. RESULTS: A mean 116.5 N distractive force was required to insert grafts into all three levels. No significant relation between preoperative disc height and distractive or compressive forces was noted. Release of the distractor yielded an immediate compressive load on each graft. The compressor significantly increased graft compression. After plate application, the external compressor was removed. Graft compression did not significantly decrease. In the loading frame, an increase in compressive load was noted. CONCLUSIONS: Preoperative disc height was not related to the compressive force on the graft. Compressive force can be increased and maintained with a dynamic plating system.

    Title Techniques in Cervical Laminoplasty.
    Date December 2003
    Journal The Spine Journal : Official Journal of the North American Spine Society
    Excerpt

    BACKGROUND CONTEXT: Laminoplasty provides an alternative to anterior procedures or multilevel laminectomy for patients with multilevel spinal stenosis and myeloradiculopathy. PURPOSE: To review the techniques, results and complications of cervical laminoplasty. STUDY DESIGN: The three basic variations of laminoplasty are the single open door, the French door or midline and the Z-plasty technique. These techniques and their outcome are discussed in detail. RESULTS: The recovery rate after laminoplasty ranges from 50% to 70% without statistical superiority of any one technique over another. Closure of opened laminae, temporary nerve root deficit, decreased neck range of motion and axial pain are the main complications of laminoplasty. CONCLUSIONS: Good to excellent long-term clinical results can be expected for the appropriately selected patients regardless of the specific technique used.

    Title Anterior Cervical Interbody Fusion with Rhbmp-2 and Tantalum in a Goat Model.
    Date December 2003
    Journal The Spine Journal : Official Journal of the North American Spine Society
    Excerpt

    BACKGROUND CONTEXT: Tricortical autogenous iliac crest has long served as the gold standard for arthrodesis after cervical discectomy. The added morbidity resulting from bone graft harvest may be eliminated by the use of a biocompatible synthetic bone graft substitute with osteoconductive abilities, and when used with an osteoinductive agent, such as recombinant bone morphogenic protein (rhBMP)-2, it may facilitate arthrodesis similar to autograft. PURPOSE: To determine by radiographic and histologic analysis whether tantalum with and without rhBMP-2 can facilitate bony ingrowth and arthrodesis in an animal model. STUDY DESIGN/SETTING: Single-level anterior cervical discectomy and fusion was performed using a tantalum bone graft substitute with and without rhBMP-2 in a previously established goat model for anterior cervical fusion. METHODS: Eight goats underwent single-level anterior cervical discectomy and stabilization with a porous tantalum implant. There were four goats in each experimental group. Group A underwent anterior cervical stabilization with tantalum alone, whereas in Group B rhBMP-2 was added to the tantalum implant. The goats were sacrificed at 12 weeks, and their cervical spines were removed for histologic and radiological analysis. RESULTS: Only one of four goats in Group A had any bony ingrowth into the tantalum. Three of four goats in Group B demonstrated bony ingrowth. The average extent of bony ingrowth at the perimeter of the tantalum in Group A was 2.5% compared with 12.5% in Group B. Similarly, the volume of bony ingrowth within the tantalum was 2.5% in Group A and 10% in Group B. The difference was not statistically significant. CONCLUSIONS: The data in this pilot study suggest that tantalum may function as a synthetic osteoconductive bone graft substitute. The addition of rhBMP-2 may facilitate osteoinduction within a synthetic osteoconductive implant. The sample size in this study was too small for statistical significance. The present animal model as used in this study was inadequate for cervical arthrodesis where rigid implant fixation is desired.

    Title Lumbar Spinal Stenosis. Treatment Strategies and Indications for Surgery.
    Date August 2003
    Journal The Orthopedic Clinics of North America
    Excerpt

    Initially, all patients with degenerative lumbar spinal stenosis should be treated conservatively. Rapid deterioration is unlikely. The majority of patients may either improve or remain stable over a long-term follow-up with nonoperative treatment. Surgery should be an elective decision by the patients who fail to improve after conservative treatment. Medical evaluation is mandatory in those elderly patients with frequent comorbidities. For central spinal stenosis, without significant grade I spondylolisthesis or deformity, decompression is the surgical treatment of choice. Iatrogenic instability must be avoided during decompression surgery by preserving the facet joint and the pars interarticularis. Limited decompression with laminotomy may be indicated for lateral canal stenosis. A limited decompression may avoid postoperative instability but is associated with more frequent neurologic sequelae. Postlaminectomy instability is uncommon, and too little decompression is a more frequent mistake than too much. Decompression is usually associated with good or excellent outcome in 80% of patients. Deterioration of initial post-operative improvement may occur over long-term follow-up. When spinal stenosis is associated with instability, degenerative spondylolisthesis, deformity, postoperative instability, or recurrent stenosis, fusion is often recommended. Instrumentation often improves the fusion rate but does not influence the clinical outcome. Generous decompression but selective fusion of the unstable segment only are preferable for degenerative spondylolisthesis and type I degenerative scoliosis with minimal rotation of the spine.

    Title Effects of Disc Height and Distractive Forces on Graft Compression in an Anterior Cervical Discectomy Model.
    Date January 2003
    Journal Spine
    Excerpt

    STUDY DESIGN: An in vitro biomechanical study using a calibrated distractor and a subminiature load cell in a cadaver anterior cervical discectomy construct was conducted. OBJECTIVE: To study the interrelations of preoperative disc height, graft height, and compressive and distractive forces in an anterior cervical discectomy model. SUMMARY OF BACKGROUND DATA: The effects of graft size on compressive and distractive forces in a discectomy model remain unknown. Larger grafts afford neural decompression through anterior column distraction. This distraction may subject the graft and vertebral bodies to excessive loads, increasing graft fracture, and subsidence risk. METHODS: Disc height was measured radiographically in 18 specimens. A Smith-Robinson discectomy was performed, and the superior and inferior ends of the specimens were embedded in polyester resin. Distraction was applied through a calibrated Caspar distractor to measure the distractive force applied while steel spacers rigidly fixed to a subminiature load cell were introduced. After distraction was removed, immediate compressive force was measured. RESULTS: Distractive forces of 112.4 N and 189.9 N were required to insert the 6-mm and 8-mm grafts, respectively. When this distractive force was removed, immediate compressive loads of 8.8 N and 21.5 N on the graft were noted. When a compressive load of 45 N was applied in a loading frame, measured graft loads of 16.2 N and 29.2 N also increased. No statistically significant relation was observed between preoperative disc height and distractive force or compression of the graft. Significantly lower distractive and compressive forces were associated with insertion of the 6-mm rather than 8-mm graft. CONCLUSIONS: Significantly higher distractive and compressive forces were recorded with larger grafts. Preoperative disc height was not an accurate predictor of graft loads.

    Title Controversies in Spine: Subspecialty Certification Should Not Be a Requirement for Spine Surgery.
    Date September 2002
    Journal Spine
    Title Controversies in Spine: Should There Be Subspecialty Certification in Spine Surgery?
    Date September 2002
    Journal Spine
    Title 1999 Cervical Spine Research Society Presidential Address: Leadership and Mentoring: Its Importance to Our Future.
    Date December 2001
    Journal Spine
    Title Lumbar Spinal Stenosis: Treatment Options.
    Date October 2001
    Journal Instructional Course Lectures
    Title Resident and Fellowship Guidelines: Educational Guidelines for Resident Training in Spinal Surgery.
    Date December 2000
    Journal Spine
    Title Effect of Anular Repair on the Healing Strength of the Intervertebral Disc: a Sheep Model.
    Date October 2000
    Journal Spine
    Excerpt

    STUDY DESIGN: The intervertebral disc, in a sheep model, was used to assess the effect of directly repairing three different anular incisions on the subsequent healing strength of the intervertebral disc. OBJECTIVES: To assess whether directly repairing an anular defect, made at the time of lumbar discectomy, could influence the healing rate and strength of the anulus fibrosus. METHODS: Twenty-four sheep underwent a retroperitoneal approach to five lumbar disc levels. An anular incision, followed by partial discectomy was done at each exposed level. Anular incisions used in this study consisted of 1) a straight transverse slit, 2) a cruciate incision, and 3) a window or box excision. Healing strength was measured at three time intervals: 2 weeks, 4 weeks, and 6 weeks. Each anular incision type was performed on 30 lumbar discs, 10 discs in each time interval. Five discs in each time interval underwent direct repair, and five discs were left unrepaired to heal as controls. The sheep were killed at 2, 4, and 6 weeks after surgery. The lumbar spines were removed en bloc, and the intervertebral discs were subjected to pressure-volume testing to assess the anular strength of repaired versus unrepaired disc injuries at each time interval. RESULTS: Statistical analysis was performed to evaluate the effects of healing time, incision technique, and repair on the pressure-volume characteristics of the involved discs. Pressure-volume testing showed trends of stronger healing for repaired discs, but at no time interval was any significant difference found between repaired and nonrepaired anular strength. Of the nonrepaired discs, the box incision was only 40 to 50% as strong as the slit or cruciate incised discs during early healing. CONCLUSION: Direct repair of anular incisions in the lumbar spine does not significantly alter the healing strength of the intervertebral disc after lumbar discectomy.

    Title Cervical Spondylotic Myelopathy and Radiculopathy.
    Date August 2000
    Journal Instructional Course Lectures
    Excerpt

    Appropriate management of degenerative cervical spine conditions requires careful elucidation of the presenting clinical syndrome. Because of the pervasiveness of degenerative changes in asymptomatic patients, a clear correlation of symptoms, physical signs, and imaging findings is required before any specific diagnosis can be made. At this time, surgery is not recommended for prophylactic decompression in asymptomatic patients or in those patients with neck pain in the absence of extremity symptoms. In most patients with radiculopathy or mild myelopathy, a trial of nonsurgical management is recommended. Ultimately, patients with neurologic complaints and in whom nonsurgical measures have failed, as well as those with more pronounced myelopathy, should be offered surgical intervention. Selection of the safest, yet sufficient, approach requires a clear understanding of the benefits and expected outcomes. The outlook for patients with both cervical radiculopathy and early myelopathy is good. Radicular symptoms usually improve, but gait and hand changes may not. LF is preferred in younger patients with posterolateral or lateral soft disk herniations, or focal foraminal osteophyte impingement and predominance of upper extremity symptoms. More central 1- or 2-level pathology should be treated with ACDF. Anterior cervical corpectomy should be entertained in patients with nondisk level encroachment and in those with 3 contiguous levels of pathology. This approach is also required in cases of kyphosis and instability. Laminoplasty is indicated in patients with 4 or more levels of stenosis, particularly in those with global conditions such as continuous OPLL or congenital stenosis. In these patients, kyphosis or severe deformity may be addressed with a circumferential approach.

    Title Spinal Stenosis.
    Date August 2000
    Journal Instructional Course Lectures
    Title Complication, Survival Rates, and Risk Factors of Surgery for Metastatic Disease of the Spine.
    Date October 1999
    Journal Spine
    Excerpt

    STUDY DESIGN: The risk factors for complications and complication and survival rates in patients with metastatic disease of the spine were reviewed. A retrospective study was performed. OBJECTIVES: To determine the surgical complication and survival rates of patients with metastatic disease of the spine and risk factors for complication occurrence. SUMMARY OF BACKGROUND DATA: The role of surgical intervention for patients with metastatic disease of the spine has been controversial. Several risk factors for surgical complications have been identified. Short survival times and high complication rates have failed to justify surgical intervention in many cases. METHODS: Patients (n = 80) undergoing surgical treatment for metastatic disease of the spine were reviewed. Surgical indications included progressive neurologic deficit, neurologic deficit failing to respond to, or progressing after, radiation treatment; intractable pain; radioresistant tumors; or the need for histologic diagnosis. Patients underwent anterior, posterior, or combined decompression and stabilization procedures. Neurologic examination was recorded before surgery, postoperative period, and at least follow-up. Complication and survival rates were calculated. Several variables were examined for risk of complication. RESULTS: The mean age at time of surgery was 55.6 years (range, 20-84 years). Mean survival time after the diagnosis of spinal metastasis was 26.0 months (range, 1-107.25 months). Mean survival time after surgery was 15.9 months (range, 0.25-55.5 months). Sixty-five patients showed no change in Frankel grade, 19 improved one Frankel grade, and 1 deteriorated one Frankel grade; 1 patient had paraplegia. Thirty-five complications occurred in 20 patients (25.0%). Ten patients (12.5%) had multiple complications accounting for 23 of the 35 postoperative problems (65.7%). Sixty patients had no surgical complications (75%). There were no intraoperative deaths. CONCLUSIONS: The likelihood that a complication occurred was significantly related to Harrington classifications demonstrating significant neurologic deficits and the use of preoperative radiation therapy. In general, Harrington classifications with neurologic deficits and lower Frankel grades before and after surgery were associated with an increased risk of complication. Overall, the major complication rate was relatively low, and minor complications were successfully treated with minimal morbidity. The relatively long survival time after spinal surgery in this group of patients justifies surgical treatment for metastatic disease. Most complications occurred in a small percentage of patients. To minimize complications, patients must be carefully selected based on expected length of survival, the use of radiation therapy, presence of neurologic deficit, and impending spinal instability or collapse caused by bone destruction.

    Title Management of Degenerative Disc Disease Above an L5-s1 Segment Requiring Arthrodesis.
    Date August 1999
    Journal Spine
    Excerpt

    Clear guidelines exist for treating spondylolisthetic deformity and instability. How the surgeon handles adjacent-level degenerative disease is not as well established. Because magnetic resonance imaging now provides us with far more information on the "health" of radiographically normal intervertebral discs, the treatment of dehydrated or degenerated discs adjacent to a fusion is becoming more problematic. In this discussion, two experts discuss their approach to symptomatic lumbosacral spondolisthesis accompanied by adjacent-level disc degeneration. Drs. Herkowitz and Abraham believe strongly that the adjacent segment should be left alone, whereas Dr. Albert recommends extending the fusion in many instances.

    Title The Use of Recombinant Human Bone Morphogenetic Protein 2 (rhbmp-2) to Promote Spinal Fusion in a Nonhuman Primate Anterior Interbody Fusion Model.
    Date June 1999
    Journal Spine
    Excerpt

    STUDY DESIGN: A study on the efficacy of recombinant human bone morphogenetic protein 2 (rhBMP-2) in a nonhuman primate anterior interbody fusion model. OBJECTIVES: To investigate the efficacy of rhBMP-2 with an absorbable collagen sponge carrier to promote spinal fusion in a nonhuman primate anterior interbody fusion model. SUMMARY OF BACKGROUND DATA: RhBMP-2 is an osteoinductive growth factor capable of inducing new bone formation in vivo. Although dosage studies using rhBMP-2 have been performed on species of lower phylogenetic level, they cannot be extrapolated to the primate. Dosage studies on nonhuman primates are essential before proceeding with human primate application. METHODS: Six female adult Macaca mulatta (rhesus macaque) monkeys underwent an anterior L7-S1 interbody lumbar fusion. All six sites were assigned randomly to one of two fusion methods: 1) autogenous bone graft within a single freeze-dried smooth cortical dowel allograft cylinder (control) or 2) rhBMP-2-soaked absorbable collagen sponges within a single freeze-dried smooth cortical dowel allograft cylinder also soaked in rhBMP-2. The animals underwent a baseline computed tomography scan followed by 3- and 6-month postoperation scans. Anteroposterior and lateral radiographs of the lumbosacral spine were performed monthly. After the monkeys were killed, the lumbar spine fusion sites were evaluated. Histologic evaluation of all fusion sites was performed. RESULTS: The three monkeys receiving rhBMP-2-soaked collagen sponges with a freeze-dried allograft demonstrated radiographic signs of fusion as early as 8 weeks. The control animals were slower to reveal new bone formation. The computed tomography scans revealed extensive fusion of the L7-S1 lumbar vertebrae in the group with rhBMP-2. A pseudarthrosis was present in two of the control animals. CONCLUSIONS: This study was able to document the efficacy of rhBMP-2 with an absorbable collagen sponge carrier and a cortical dowel allograft to promote anterior interbody fusion in a nonhuman primate model at a dose of 0.4 mg per implant site (1.5 mg/mL concentration). The late of new bone formation and fusion with the use of rhBMP-2 and cortical dowel allograft appears to be far superior to that of autogenous cancellous iliac crest graft with cortical dowel allograft.

    Title Indications and Trends in Use in Cervical Spinal Fusions.
    Date February 1999
    Journal The Orthopedic Clinics of North America
    Excerpt

    Anterior cervical decompression and arthrodesis has evolved over the last 40 years and has become the preferred procedure for managing many cervical spine disorders. The first half of this article discusses the indications for cervical fusion in the management of traumatic, degenerative, neoplastic, infectious, and congenital conditions of the cervical spine. The second half of this article discusses the recent trends in use of cervical spine fusions that demonstrate the increasing frequency of this procedure in the United States over the last 10 years.

    Title Indications for Thoracic and Lumbar Spine Fusion and Trends in Use.
    Date February 1999
    Journal The Orthopedic Clinics of North America
    Excerpt

    Over the last 10 years, the annual number of spinal procedures performed in the United States has more than doubled. In 1996, there were roughly 29,000 thoracic or dorsal fusion procedures, which made up almost 13% of all spine fusions performed. Scoliosis was the most common condition necessitating posterior thoracic fusion. The first half of this article focuses on the indications for thoracic and lumbar fusions; whereas, the second half of this article discusses the trends in use of thoracic and lumbar spine fusions.

    Title The Role of Prophylactic Antibiotics in Spinal Instrumentation. A Rabbit Model.
    Date June 1998
    Journal Spine
    Excerpt

    STUDY DESIGN: A rabbit model was used to test the efficacy of cefazolin administered in various therapeutic regimens in preventing iatrogenic Staphylococcus aureus infections during spinal instrumentation. OBJECTIVE: To assess the efficacy of various prophylactic therapeutic regimens of cefazolin in preventing iatrogenic S. aureus infections during spinal instrumentation. SUMMARY OF BACKGROUND DATA: Previous studies have not dealt specifically with the occurrence of iatrogenic S. aureus infections during spinal instrumentation in a prospective fashion. METHODS: Twenty New Zealand White rabbits underwent a posterior approach to the lumbar spine. Fifteen of the animals then had double-braided 26-gauge surgical wire placed around bilateral L3-L4 and L4-L5 facet joints. A standardized volume of a 103 S. aureus/mL of solution was then inoculated onto the fusion-hardware site in all rabbits. The rabbits were divided into four groups receiving various antibiotic dose regimens. Five days after surgery, the animals were killed, and cultures were obtained. RESULTS: All of the rabbits receiving no antibiotic had fusion sites infected with S. aureus. None of the animals who received prophylactic cefazolin produced cultures that grew S. aureus. A specimen from one fusion site cultured Staphylococcus epidermidis, which is not sensitive to cefazolin. Analysis of these data using Fisher's exact test resulted in a P value of 0.008 when results in antibiotic groups were compared with those in a group receiving no antibiotics and a P value of 0.0003 when all groups were compared. CONCLUSIONS: This model was valid and reproducible for the study of spinal instrumentation and infection. In addition, the data support the efficacy and use of prophylactic intravenous antibiotics in preventing infection in spinal instrumentation and fusion surgery.

    Title Computed Tomography-guided Biopsy of the Spine. A Review of 103 Patients.
    Date March 1998
    Journal Spine
    Excerpt

    STUDY DESIGN: A retrospective study of 103 computed tomography-guided biopsies of the spine. These represent a consecutive series of patients with spinal lesions or disorders observed over a 32-month period. OBJECTIVES: To determine the diagnostic accuracy and clinical usefulness of computed tomography-guided biopsies with respect to major influencing variables. SUMMARY OF BACKGROUND DATA: Computer tomographic-guided biopsy of the spine is considered a safe, accurate, and relatively inexpensive examination technique. A study comparing its diagnostic accuracy with respect to all the variables of age, gender, radiographic appearance, spinal level, tissue type, or pathologic diagnosis has not been done. METHODS: Biopsy specimens were sent for cytologic and histologic analysis. Bacteriologic studies were performed when clinically indicated. The biopsy results were analyzed for adequacy and diagnostic accuracy, i.e., the ability to generate a tissue sample adequate for pathologic examination and one that yields diagnostic information. RESULTS: The mean age of patients was 60 years, with a range of 4-91 years. The spines of 52 males and 51 females were studied. There were eight cervical, 28 thoracic, 53 lumbar, and 14 sacral lesions used as biopsy sites. The radiographic appearance of spinal lesions were lytic in 74 cases, blastic in four cases, and mixed in two cases. Tissues undergoing biopsy included bone (63 cases), soft tissue (35 cases), and mixed specimens (five cases). The pathologic examinations revealed 18 infections, 23 primary neoplasms, 34 metastases, and 19 normal tissues. An adequate specimen for pathologic examination was obtained in 90 biopsies (87%). A diagnosis was achieved in 67 of 94 patients (71%). Diagnostic rates obtained in thoracic level biopsies were lower than those from biopsies of other spinal levels (P = .007). CONCLUSION: Computed tomography-guided biopsy is an important tool in the evaluation of spinal lesions. A positive biopsy result may preclude the need for open surgical intervention. This study included one of the largest series of patients in the medical literature. In addition, it determined the diagnostic rates of this procedure with respect to the major influencing variables. Thoracic-level biopsies have a diagnostic rate that is significantly lower than that of other spinal levels. No significant correlation was found between diagnostic accuracy and age, gender, radiographic appearance, tissue type, or eventual diagnosis.

    Title Augmentation of Autograft Using Rhbmp-2 and Different Carrier Media in the Canine Spinal Fusion Model.
    Date March 1998
    Journal Journal of Spinal Disorders
    Excerpt

    This study evaluated the use of recombinant human bone morphogenetic protein (rhBMP-2) with various types of carrier media, and the effect of rhBMP-2 as an adjunct to autogenous iliac crest bone graft in the canine spinal fusion model. BMP induces mesenchymal cells to differentiate into cartilage and bone. The recent availability of rhBMP-2 has created the opportunity to evaluate this material's properties in augmenting autogenous bone graft in spinal fusion. Currently, the most appropriate type of carrier media for rhBMP-2 is undetermined. Bilateral intertransverse spinal fusions were performed on six canine lumbar spines at L1-L2, L3-L4, and L5-L6, using autogenous posterior iliac crest bone graft at each level, creating a total of 18 segmental fusion sites. All 18 sites were then randomly assigned to one of six fusion methods: autogenous bone graft (ABG) alone, ABG + rhBMP-2, ABG + collagen (Helistat) "sandwich" + rhBMP-2, ABG + collagen (Helistat) morsels + rhBMP-2, ABG + polylactic/glycolic acid sponge (PLGA) sandwich + rhBMP-2, and ABG + open-pore polylactic acid morsels + rhBMP-2. Each material was evaluated for ease of handling and application at the index surgery. The animals underwent computed tomography (CT) scanning of the lumbar fusion sites after 8 weeks. Volumetric measurements of total fusion mass at each level were performed using two-dimensional CT scan slices and a volumetric program supplied by the Siemens Medical System. The animals were killed after imaging studies. The lumbar spine fusion sites were evaluated for integrity of the fusion mass, both visually and with manual mechanical stressing. Crossover of the fusion mass to adjoining levels was also evaluated. Histologic evaluation of all fusion sites was performed. The addition of rhBMP-2 significantly increased bone graft volume as noted on CT scan. Carrier that could be mixed with morselized bone graft offered easier handling and application and all spine segments fused. Polylactic/glycolic acid (PLGA) sites were associated with a greater incidence of voids within the fusion mass. No significant difference in carrier media for rhBMP-2 could be determined. However, PLGA was associated with a higher rate of fusion mass void formation. rhBMP-2, when added to autograft, significantly increased the volume and the maturity of the resulting fusion mass.

    Title 1997 Volvo Award Winner in Clinical Studies. Degenerative Lumbar Spondylolisthesis with Spinal Stenosis: a Prospective, Randomized Study Comparing Decompressive Laminectomy and Arthrodesis with and Without Spinal Instrumentation.
    Date February 1998
    Journal Spine
    Excerpt

    STUDY DESIGN: This prospective study analyzed the influence of transpedicular instrumented on the operative treatment of patients with degenerative spondylolisthesis and spinal stenosis. OBJECTIVES: To determine whether the addition of transpedicular instrumented improves the clinical outcome and fusion rate of patients undergoing posterolateral fusion after decompression for spinal stenosis with concomitant degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Decompression is often necessary in the treatment of symptomatic patients who have degenerative spondylolisthesis and spinal stenosis. Results of recent studies demonstrated that outcomes are significantly improved if posterolateral arthrodesis is performed at the listhesed level. A meta-analysis of the literature concluded that adjunctive spinal instrumentation for this procedure can enhance the fusion rate, although the effect on clinical outcome remains uncertain. METHODS: Seventy-six patients who had symptomatic spinal stenosis associated with degenerative lumbar spondylolisthesis were prospectively studied. All patients underwent posterior decompression with concomitant posterolateral intertransverse process arthrodesis. The patients were randomized to a segmental transpedicular instrumented or noninstrumented group. RESULTS: Sixty-seven patients were available for a 2-year follow-up. Clinical outcome was excellent or good in 76% of the patients in whom instrumentation was placed and in 85% of those in whom no instrumentation was placed (P = 0.45). Successful arthrodesis occurred in 82% of the instrumented cases versus 45% of the noninstrumented cases (P = 0.0015). Overall, successful fusion did not influence patient outcome (P = 0.435). CONCLUSIONS: In patients undergoing single-level posterolateral fusion for degenerative spondylolisthesis with spinal stenosis, the use of pedicle screws may lead to a higher fusion rate, but clinical outcome shows no improvement in pain in the back and lower limbs.

    Title Spinal Stenosis: Indications for Laminectomy.
    Date June 1997
    Journal Instructional Course Lectures
    Title Lumbar Spinal Stenosis: Indications for Arthrodesis and Spinal Instrumentation.
    Date June 1997
    Journal Instructional Course Lectures
    Title Efficacy of Closed Wound Suction Drainage After Single-level Lumbar Laminectomy.
    Date May 1997
    Journal Journal of Spinal Disorders
    Excerpt

    The use of closed suction drainage after spinal surgery remains controversial. The purpose of this study was to determine the indications for closed suction drainage after single-level lumbar surgery. Two hundred patients who were scheduled to undergo single-level lumbar surgery without fusion were prospectively randomized into two groups. One group had a closed wound suction drain placed deep to the lumbodorsal fascia before routine closure, whereas the second group had no drain placed. Hemostasis was achieved in all patients before the surgeon had knowledge of the randomization outcome. All drains were removed on the 2nd postoperative day, and the amount of drainage was recorded. After surgery, the patients were evaluated for signs and symptoms of continued wound drainage, hematoma/seroma formation, and/or infection as well as evidence of an acquired neurologic deficit. One hundred three patients had a drain placed before closure and two patients developed postoperative wound infection, both of which were successfully treated with orally administered antibiotics. Of the 97 patients who had no drain placed after the surgical procedure, one patient developed a postoperative wound infection that was treated with surgical incision and drainage, as well as intravenously administered antibiotics. Statistical analysis revealed that the presence or absence of a drain did not affect the postoperative infection rate. No new neurologic deficits occurred in any postoperative patient. The use of drains in single-level lumbar laminectomy without fusion did not affect patient outcome. There was no significant difference in the rate of infection or wound healing and no patient developed a postoperative neurologic deficit.

    Title Spinal Instrumentation in the Management of Degenerative Disorders of the Lumbar Spine.
    Date February 1997
    Journal Clinical Orthopaedics and Related Research
    Excerpt

    The use of spinal instrumentation as an adjunct to fusion for the treatment of degenerative disorders of the lumbar spine is controversial. Instrumented lumbar fusions, in specific instances, may improve patient outcomes. For patients undergoing single level primary lumbar arthrodesis, the available data do not conclusively support the efficacy of spinal instrumentation. However, in the setting of previous failed lumbar surgery, iatrogenic or degenerative lumbar spondylolisthesis, spinal instrumentation may be useful as an adjunct to fusion. Possible advantages associated with the use of instrumentation include: correction of deformity in frontal and sagittal planes; decreased pseudarthrosis rates; prevention of progression of spondylolisthesis, and provision of spinal stability in the absence of intact posterior elements. Complications associated with the use of instrumentation include: increased cost; increased operative times; increased infection rate; increased reoperation rate; and a steep learning curve. Therefore, when instrumentation is to be used, the benefits must outweigh the risks. These risks can be minimized by the judicious use of instrumentation by experienced surgeons, for specific indications as supported by the literature.

    Title Is Pathology Examination of Disc Specimens Necessary After Routine Anterior Cervical Discectomy and Fusion?
    Date February 1997
    Journal Spine
    Excerpt

    STUDY DESIGN: A retrospective chart review was performed from 1990-1994. OBJECTIVES: To evaluate the outcome of pathologic examination of cervical disc specimens submitted after anterior cervical discectomy. SUMMARY OF BACKGROUND DATA: This study is the first to review the outcome of pathologic examination of disc specimens after anterior cervical discectomy and fusion. METHODS: Charts were reviewed based on the procedure code of anterior cervical fusion and the main diagnoses of cervical disc and spondylosis. The following data were recorded for each patient: symptoms, examination, diagnostic studies, operative procedure, operative findings, and pathology report. Statistical analysis was performed. RESULTS: Five hundred six disc levels in 394 patients were reviewed. All patients had symptoms and examination results consistent with cervical radiculopathy. All patients had cervical radiographs and some combination of myelography, computed tomography, or magnetic resonance imaging. Findings at the time of surgery included the presence of either a herniated disc or degenerative spondylitic changes. The pathologic examination results of all specimens reported fibrocartilaginous tissue consistent with disc material with the presence of degenerative changes. No infectious, benign, or malignant process was identified at the time of surgery or on gross and histologic examination of any of the disc specimens. Using confidence intervals (95%) for exact proportions and given 500 negatives, the chance the next occurrence would be positive would be 0.0060 or 0.60% or six of 1000. CONCLUSIONS: This study shows that if the symptoms, physical examination, radiographic diagnostic studies, and surgical findings are consistent with those of cervical disc herniation of spondylosis, the chance of an unexpected, clinically important pathologic finding within the disc specimen is extremely small. The time and expense involved in routine pathologic examination of cervical disc specimens can be avoided.

    Title The Effect of Interposition Membrane on the Outcome of Lumbar Laminectomy and Discectomy.
    Date January 1996
    Journal Spine
    Excerpt

    STUDY DESIGN. This study evaluated clinical and magnetic resonance imaging differences of patients treated surgically for lumbar disc herniation. Clinical follow-up and magnetic resonance imaging evaluation of epidural fibrosis were used to assess patient outcome. OBJECTIVES. The purpose of this study was to evaluate the difference in clinical outcome with either free-fat graft, Gelfoam, or no interposition membrane placed in the laminectomy defect after nerve root decompression. SUMMARY OF BACKGROUND DATA. Epidural fibrosis has been considered a cause of recurrent symptoms after lumbar laminectomy, and numerous materials have been evaluated for prophylaxis of the "laminectomy membrane." These have been mainly histologic and animal studies with no data correlating clinical symptoms and postoperative epidural scar formation. METHODS. One hundred fifty-six patients who were treated surgically for lumbar disc herniation were randomly assigned to one of three groups and followed prospectively for at least 1 year. Thirty-three of these patients were received magnetic resonance imaging evaluations after 6 months by an independent radiologist who graded the amount of epidural scar formation. The patients were assessed at 1 year and given a rating of excellent, good, fair, or poor, and the scar was graded as none, minimal, or moderate. RESULTS. Although 97% of all patients improved, 83% were rated excellent or good. There were no statistical differences between the three groups clinically and radiographically. Patients with workers compensation had a statistically significant lower success rate (P < 0.001). CONCLUSIONS. Clinical outcome after lumbar disc surgery does not correlate with the use or type of interposition membrane used to prevent epidural fibrosis.

    Title Spine Update. Degenerative Lumbar Spondylolisthesis.
    Date September 1995
    Journal Spine
    Excerpt

    Degenerative lumbar spondylolisthesis associated with spinal stenosis is a common condition of the aging spine. This article presents a detailed description of the pathophysiology, clinical presentation, and nonoperative and operative intervention of this condition.

    Title Conus Medullaris Injury Due to Herniated Disk and Intraoperative Positioning for Arthroscopy.
    Date August 1995
    Journal Journal of Spinal Disorders
    Excerpt

    This report discusses the occurrence of a cauda equina syndrome from a herniated L1-L2 disc following knee arthroscopy.

    Title The Effect of Prophylactic Antibiotics on Iatrogenic Intervertebral Disc Infections. a Rabbit Model.
    Date August 1995
    Journal Spine
    Excerpt

    STUDY DESIGN. A rabbit model was used to test the efficacy of two commonly used prophylactic antibiotics, cefazolin and vancomycin, in preventing iatrogenically introduced Staphylococcus aureus intervertebral disc infections. OBJECTIVE. This study was performed to assess the efficacy of two prophylactic antibiotics in preventing iatrogenically introduced Staphylococcus aureus intervertebral disc infections. SUMMARY OF BACKGROUND DATA. Previous studies have had conflicting results regarding the penetration of antibiotics into the nucleus pulposus and their ability to eradicate infection. METHODS. In this study, 40 adult New Zealand White rabbits underwent inoculation of 10(1) or 10(3) Staphylococcus aureus/ml into 3-6 lumbar intervertebral discs under direct visualization. Either no antibiotics (control groups) or various preoperative and postoperative dosing schedules of cefazolin or vancomycin were given intravenously. Five days after surgery, the discs were harvested and cultured. RESULTS. All 40 discs inoculated in the control groups became infected. None of the 35 discs inoculated in the cefazolin groups became infected. Infection developed in 23 of 107 discs inoculated in the vancomycin groups. Most notable of these were 17 of 17 positive cultures in animals given vancomycin 8 hours preoperatively only. CONCLUSIONS. Based on these results, it was concluded that intravenous cefazolin or vancomycin given within 1 hour before surgery can effectively prevent postoperative discitis. No advantage was found with additional postoperative antibiotics.

    Title A Modified Posterolateral Approach to the Thoracic Spine.
    Date May 1995
    Journal Journal of Spinal Disorders
    Excerpt

    We describe a modified technique for posterolateral approach to the thoracic spine and report the use of this procedure in 21 patients. The technique is safe and effective for selected indications. The evolution of the posterolateral or costotransversectomy approach to the thoracic spine has in large part focused on enlarging the exposure to the vertebral bodies and epidural space by resecting an increasing number of ribs and removing a wider portion of those ribs resected. In this modified approach to the thoracic spine, the costovertebral articulation is preserved, and no rib resection is necessary to gain adequate exposure to the thoracic vertebral body and epidural space. We did a retrospective review of 21 patients undergoing 22 modified posterolateral approaches to the thoracic spine. Sixteen patients had biopsies of thoracic vertebral lesions through this approach; 3 underwent decompression of the thoracic spinal cord; 2 approaches were done for the removal of a herniated thoracic disc; and in one, the pedicle was removed. This modified posterolateral approach allowed adequate exposure for selected indications. One complication, a wound infection, developed after biopsy for suspected osteomyelitis. This modified posterolateral approach is well suited to provide access for biopsy of thoracic spinal lesions; for decompression of a paraspinal abscess; and for decompression of the thoracic spinal cord by anterolateral compressive lesions such as herniated thoracic disc or epidural tumor when resection of the vertebral body is not necessary; or the approach may be used for patients who are debilitated or at poor risk to undergo thoracotomy.

    Title Anular Incision Technique on the Strength and Multidirectional Flexibility of the Healing Intervertebral Disc.
    Date July 1994
    Journal Spine
    Excerpt

    STUDY DESIGN. This study used a sheep model to biomechanically analyze the healing strength of the anulus fibrosus after two types of anular incisions. OBJECTIVE. This study evaluated whether the type of anular incision made at the time of lumbar discectomy plays a role in the subsequent healing strength of the anulus and the biomechanical flexibility of the corresponding motion segment. METHODS. Two types of anular incision, a full thickness removal of a box or window of anulus and a full thickness straight transverse slit through the anulus, were made in the intervertebral discs of 18 adult sheep. After healing times of 2, 4, and 6 weeks, the intervertebral discs were tested versus control levels for strength of anular healing and biomechanical flexibility of the corresponding motion segment. RESULTS. The box incised discs showed a significantly greater loss in strength during the early healing phase (2 to 4 weeks) and a longer response before recovering anular strength when compared with the slit-incised discs. The type of incision also affected the multidirectional flexibility of the motion segments in a differentiated manner. Larger amounts of motion were seen with the box incision when compared with the slit incision at all time periods and in all pure moments. CONCLUSION. The technique of anular incision plays a definite role in the timing and strength of subsequent anular healing. The box incision through the anulus led to significantly weaker healing than did the slit incision in the early healing phase (2-4 weeks). Also, larger amounts of motion were seen in the vertebral motion segments of those discs undergoing box incision when compared with slit or control levels.

    Title A Biomechanical Comparison of Cervical Laminaplasty and Cervical Laminectomy with Progressive Facetectomy.
    Date February 1994
    Journal Spine
    Excerpt

    The effects of multilevel cervical laminaplasty and laminectomy with increasing amounts of facetectomy on stability of the cervical spine were tested with physiologic loading in nine cadaveric specimens. Cervical spines, levels C2-C7, were tested with physiologic loading in a constraint-free test system, the motion of each body being tracked in a three-dimensional coordinate system. Cervical laminectomy with 25% or more facetectomy resulted in a highly significant increase in cervical motion compared to the intact specimens for the dominant motions of flexion/extension (P < 0.003), axial torsion (P < 0.001), and lateral bending (P < 0.001). Cervical laminaplasty was not significantly different from the intact control, except for a marginal increase in axial torsion. Coupled motion did not change with laminaplasty or laminectomy with progressive facetectomy. As little as 25% facetectomy adversely affects stability after multilevel cervical laminectomy. Cervical laminaplasty avoids this problem, while still affording multilevel decompression. Therefore in patients undergoing cervical laminectomy accompanied by more than 25% bilateral facetectomy, concurrent arthrodesis should be performed.

    Title Spinal Pedicle Fixation. Confirmation of an Image-based Technique for Screw Placement.
    Date December 1993
    Journal Spine
    Excerpt

    Although many advances in the technique of pedicle screw insertion have been made, there still exist unacceptable rates of perforations through the pedicle cortex. Successful placement of a pedicle screw requires accurate identification of the entry point, correct transverse and sagittal plane angulation, safe preparation of a pilot hole, and appropriate depth of insertion. The authors propose that a technique of pedicle screw insertion using posteroanterior image intensification angled in the axis of the pedicle to define the entry point and guide insertion would improve the accuracy of this procedure. This study tests the accuracy of pedicle screw placement using this technique. Ninety pedicle screws were placed in human cadaveric lumbar spines. All specimens were then dissected and split longitudinally to assess accuracy of pedicle insertion by both visual and palpatory means. Five of 90 (5.5%) pedicle screws were found to have perforated the pedicle. Three of these were at L1, two of which were due to the transverse pedicle diameter being smaller than the screw diameter. Therefore, a 3.4% incidence of pedicle perforation due to malpositioning and a 2.1% incidence of pedicle perforation secondary to pedicle/screw size discrepancy was determined. This technique may lead to significant improvements over recently reported rates of pedicle screw perforations; however, this in vitro condition eliminated many potentially complicating factors that might be encountered in the clinical setting.

    Title Upper Lumbar Disc Herniations.
    Date December 1993
    Journal Journal of Spinal Disorders
    Excerpt

    This study reviews the presentation, diagnosis, and outcomes of upper lumbar disc herniations (L1-2, L2-3, L3-4). One hundred forty-one patients operated upon at three centers between 1980 and 1990 were analyzed (102 men, 39 women; 3 L1-2, 21 L2-3, 117 L3-4; average age 51.6 years; 10.4% of all lumbar discectomies performed). Preoperative signs and symptoms were highly variable. Sensory, motor, and reflex testing was variable and potentially misleading in suggesting a level of herniation. In analyzing radiographic studies (noncontrast CT, myelography, MRI) individually and using other radiographic studies and operative findings as a standard for comparison, a high false-negative rate was found for all studies when considered individually, especially at the higher L2-3 level. Intraoperative radiographs were employed with increasing frequency as the level of herniation ascended. Six operative complications (4.3%) were identified, all of which were treated and were resolving at the time of discharge. Follow-up obtained at an average of 2.2 years in 87% of patients by chart review showed no reoperations or late complications. Noncompensation patients had a significantly higher percentage of good/excellent results (86%) than those with compensation or legal claims pending (45% good/excellent results). Based upon these data, we recommend myelogram with postmyelogram CT and/or MRI in the workup of these patients and intraoperative radiographs in all cases when decompressing an upper lumbar disc herniation. Patients with compensation/legal claims should be approached cautiously, because their subjective results are significantly worse than those of noncompensation patients.(ABSTRACT TRUNCATED AT 250 WORDS)

    Title Pseudarthrosis of the Spine.
    Date November 1992
    Journal Clinical Orthopaedics and Related Research
    Excerpt

    Pseudarthrosis remains the leading cause of failed spinal fusions. The common causes of this complication are inadequate surgical technique, excessive stresses across the fusion site, insufficient internal or external stabilization, and unrecognized metabolic abnormalities. Many radiologic techniques have been used to diagnose pseudarthrosis in the spine. Nonetheless, the diagnosis of a nonunion as well as the ability to correlate the nonunion with the patient's clinical symptoms remains a challenge. In treating a symptomatic pseudarthrosis, the surgeon should first attempt to identify those factors that contributed to the development of a nonunion. The approach can then either be exploration of the fusion mass with regrafting of the pseudarthrosis or extending a fusion to locations within the abnormal segment of spinal motion.

    Title Surgical Management of Myelopathy.
    Date August 1992
    Journal The Orthopedic Clinics of North America
    Excerpt

    We have presented a comparative analysis of the ability of four surgical procedures to address adequately the problems sustained by a patient with symptomatic cervical myelopathy. AIA is a safe procedure whose effectiveness may be limited when the extent of disease is more than three intervertebral disk levels. ACA permits more direct and extensive access to the spinal cord and is the procedure of choice for cervical spondylotic myelopathy associated with spinal deformity. However, rigid external immobilization is necessary, and operative morbidity may be greater. Cervical laminectomy may be effective for decompressing the spinal cord when no associated spinal deformity or instability is present, provided that extensive resection of facet joints is avoided. Cervical laminaplasty is ideally suited for the patient with three or more levels contributing to a cervical myeloradiculopathy. Mild instability may be addressed by performing arthrodesis on the hinge side.

    Title Spinal Stenosis: Clinical Evaluation.
    Date June 1992
    Journal Instructional Course Lectures
    Title Modified Anterior Approach to the Cervicothoracic Junction.
    Date April 1992
    Journal Spine
    Excerpt

    The surgical management of tumors at the cervicothoracic junction is hindered by various anatomic structures. Standard approaches to the cervical or thoracic spine provide inadequate exposure. An approach to the cervicothoracic junction that provides exposure from C3 to T4 is described. The approach allows extensive bony resection, spinal cord decompression, correction of deformity, spinal reconstruction, and stabilization. Four patients with tumors metastatic to the cervicothoracic junction underwent this surgical approach. All had significant kyphosis and neck pain unresponsive to nonsurgical treatment. After surgery, neurologic function improved in three patients and remained normal in one. All patients had relief of neck pain and reduction of kyphosis.

    Title Cervical Laminaplasty: Its Role in the Treatment of Cervical Radiculopathy.
    Date April 1992
    Journal Journal of Spinal Disorders
    Excerpt

    Krita in 1968 described the use of laminaplasty for the treatment of cervical myelopathy. Since then, several authors have modified this technique, settling on the "expansive open door laminaplasty" as the technique of choice for cervical myelopathy. There have been no reports to date on the use of the cervical laminaplasty procedure for the treatment of cervical radiculopathy. The purpose of this paper is to report on the initial 16 patients undergoing this procedure for the surgical treatment of cervical radiculopathy due to cervical spondylosis and/or cervical spinal stenosis. There were 16 patients (8 males and 8 females) whose age ranged from 54 to 84 years, with a mean of 67.2 years. The follow-up average was 2.7 years, with a range of 2.1 to 5.5 years. Seven patients were categorized as having brachalgia-cord type myelopathy and nine patients were categorized as radiculopathy only. Arm pain was unilateral in seven patients and bilateral in nine patients. Of those with bilateral pain, eight patients had pain predominately in one arm, with one patient having equal left and right arm complaints. Cervical laminaplasty was carried out from C3-6 in six patients and C3-7 in six patients and one patient had each of the following: C4-7, C4-T1, C5-T1, and C3-T1. The results were excellent in five cases, good in nine, and poor in two. The results of patients with unilateral symptoms and signs were compared to those with bilateral findings using chi 2 analysis. There was no statistical difference when performing laminaplasty for patients with bilateral findings as opposed to unilateral symptoms and signs. The amount of spinal canal expansion obtained by the laminaplasty procedure ranged from 4 to 12 mm. The conclusions of this study were (a) laminaplasty appears to be an effective alternative to laminectomy or anterior cervical fusion for multilevel cervical spondylotic radiculopathy or myeloradiculopathy and (b) complications of anterior fusion and laminectomy are avoided with the laminoplasty procedure.

    Title Degenerative Lumbar Spondylolisthesis with Spinal Stenosis. A Prospective Study Comparing Decompression with Decompression and Intertransverse Process Arthrodesis.
    Date August 1991
    Journal The Journal of Bone and Joint Surgery. American Volume
    Excerpt

    Fifty patients who had spinal stenosis associated with degenerative lumbar spondylolisthesis were prospectively studied clinically and radiographically to determine if concomitant intertransverse-process arthrodesis provided better results than decompressive laminectomy alone. There were thirty-six women and fourteen men. The mean age of the twenty-five patients who had had an arthrodesis was 63.5 years and that of the twenty-five patients who had not had an arthrodesis, sixty-five years. The level of the operation was between the fourth and fifth lumbar vertebrae in forty-one patients and between the third and fourth lumbar vertebrae in nine patients. The patients were followed for a mean of three years (range, 2.4 to four years). In the patients who had had a concomitant arthrodesis, the results were significantly better with respect to relief of pain in the back and lower limbs.

    Title Current Status of Percutaneous Discectomy and Chemonucleolysis.
    Date May 1991
    Journal The Orthopedic Clinics of North America
    Excerpt

    This article provides an updated review of chemonucleolysis and percutaneous discectomy. Dr. Herkowitz recommends discontinuing the use of chymopapain. Percutaneous discectomy may play a small role in the invasive management of a lumbar disc herniation.

    Title Natural History of Os Odontoideum.
    Date May 1991
    Journal Journal of Pediatric Orthopedics
    Excerpt

    Os odontoideum has recently been considered an acquired lesion of the second cervical vertebrae. This case documents the natural progression of the formation of os odontoideum and correlates it with a traumatic event. This is the first case reported in the literature.

    Title Osteolytic Monostotic Paget's Disease of the Fifth Lumbar Vertebra. A Case Report.
    Date February 1991
    Journal Clinical Orthopaedics and Related Research
    Excerpt

    Osteolytic monostotic Paget's disease or osteitis deformans of the fifth lumbar vertebra occurred in a 55-year-old woman. An isolated lytic process involving the entire vertebral body and posterior elements and an open biopsy showed extensive remodeling with cement lines, myelofibrosis, and osteoclastic resorption typical of Paget's disease.

    Title Surgical Management of Cervical Soft Disc Herniation. A Comparison Between the Anterior and Posterior Approach.
    Date February 1991
    Journal Spine
    Excerpt

    Anterior cervical fusion was initially described in the 1950s for cervical spondylotic radiculopathy. The indications for this procedure in the management of soft disc herniation have not been clearly defined. In addition, controversy exists as to whether a cervical soft herniation should be managed by an anterior approach or a posterior cervical laminotomy-foraminotomy. The authors report the results of a prospective study comparing anterior discectomy and fusion to posterior laminotomy-foraminotomy for the management of soft cervical disc herniation. Twenty-eight patients underwent anterior discectomy and fusion (Robinson horseshoe graft) while 16 patients underwent posterior laminotomy-foraminotomy. The disc herniations were classified into two types. Type I were single level anterolateral herniations (33 patients) while type II were central soft disc herniations (11 patients). Clinically, patients with type I herniations manifested signs and symptoms of radiculopathy while patients with type II herniations manifested signs of myelopathy or neck pain and bilateral upper extremity paresthesias in 4 patients. Confirmatory studies were myelography in 12 patients, myelography combined with computed tomography (CT) in 26 patients, and magnetic resonance imaging (MRI) in 6 patients. For type I herniations, 17 patients underwent anterior fusion while 16 patients had a posterior laminotomy-foraminotomy. The 11 patients classified as type II herniation all underwent anterior discectomy and fusion. There were 27 men and 17 women. The age range was 21 to 52 years (mean, 41 years). The follow-up was 1.6 to 8.2 years (mean, 4.2 years).(ABSTRACT TRUNCATED AT 250 WORDS)

    Title The Surgical Management of Cervical Spondylotic Radiculopathy and Myelopathy.
    Date March 1989
    Journal Clinical Orthopaedics and Related Research
    Excerpt

    Anterior fusion, laminectomy, and laminaplasty are recommended for the following conditions. For the treatment of one- or two-level spondylotic radiculopathy, anterior discectomy and fusion are preferred. For the treatment of spondylotic radiculopathy involving three or more levels, the open-door laminaplasty may be considered an alternative to anterior fusion. In this situation, laminaplasty is preferred for patients with developmental cervical canal stenosis, failed anterior fusion, or various prior anterior neck operations. Cervical laminectomy is indicated for patients with anterior bony ankylosis secondary to degenerative or inflammatory disorders and for patients in whom anterior fusion may be technically difficult, i.e., at C1-C3 or C7-T1. Anterior fusion is advisable for patients who have a structural reversal of the normal lordotic curve.

    Title A Comparison of Anterior Cervical Fusion, Cervical Laminectomy, and Cervical Laminoplasty for the Surgical Management of Multiple Level Spondylotic Radiculopathy.
    Date January 1989
    Journal Spine
    Excerpt

    The risks and success of surgery for multiple level cervical spondylotic radiculopathy differs from that of single level disease. The problems associated with multiple level anterior fusion over single level fusion include higher pseudoarthrosis rates than that associated with single level disease. Bilateral and multiple level laminectomy carries the risk of potential instability. Cervical laminoplasty, until recently, has only been performed for myelopathy secondary to ossification of the posterior longitudinal ligament (OPLL) or cervical stenosis. The purpose of this report is to compare the results and complications of 45 patients with a least a 2-year follow-up who had undergone anterior fusion, cervical laminectomy, or cervical laminoplasty for the surgical management of multiple level cervical radiculopathy due to cervical spondylosis. 18 patients (58 levels) underwent anterior fusion, 12 patients (38 levels) had a cervical laminectomy, and 15 patients (57 levels) underwent a cervical laminoplasty. Roentgenograms indicated spinal stenosis (sagittal diameter less than 12 mm) at 28 levels (15 patients) for the anterior fusion group, 14 levels (9 patients) in the laminectomy group, and 24 levels (13 patients) in the laminoplasty group. Subluxation (2 mm or less) was present at 14 levels (13 patients) in the anterior fusion group, nine levels (9 patients) in the laminectomy group, and 15 levels (8 patients) in the laminoplasty group. Loss of lordosis was present in eight patients undergoing anterior fusion, six patients undergoing laminectomy, and six patients who had a laminoplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

    Title Osteolytic Monostotic Paget's Disease of the Axis. A Case Report.
    Date July 1988
    Journal Spine
    Title The Use of Computerized Tomography in Evaluating Non-visualized Vertebral Levels Caudad to a Complete Block on a Lumbar Myelogram. A Review of Thirty-two Cases.
    Date March 1987
    Journal The Journal of Bone and Joint Surgery. American Volume
    Excerpt

    In thirty-two patients who demonstrated a complete or almost complete block on a lumbar myelogram, computerized tomography of the non-visualized vertebral levels caudad to the block was performed prior to surgical intervention. The purpose of this study was to evaluate the clinical value of computerized tomography in detecting a lesion that is caudad to the level of a myelographic block. For twenty-three patients the cause of the myelographic block was stenosis of the spine; for five patients, a combination of stenosis of the spine and herniation of a disc; for one patient, herniation of a disc between the fourth and fifth lumbar vertebrae alone; for two patients, arachnoiditis; and for one patient, kyphosis secondary to fracture. A total of fifty vertebral levels that could not be visualized because of the block were evaluated. Thirty (60 per cent) of the non-visualized vertebral levels, in nineteen (59 per cent) of the thirty-two patients, demonstrated stenosis of the spine or a herniated disc that was confirmed at the time of surgical treatment. The value of computerized tomography for the evaluation of the vertebral levels caudad to the level of a complete or almost complete block on a lumbar myelogram was threefold. First, it provided visualization of the vertebral levels that could not be evaluated by the myelography. Second, the findings on computerized tomography provided information that was essential for preoperative planning and it removed the so-called exploratory element from the operative procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

    Title Sciatica from a Sciatic Neurilemoma. A Case Report and Review of the Literature.
    Date January 1987
    Journal The Journal of Bone and Joint Surgery. American Volume
    Title The Cervical Spine in Hemophilia.
    Date November 1986
    Journal Clinical Orthopaedics and Related Research
    Excerpt

    Fifty-three patients with known hemophilia A or B were retrospectively reviewed to determine the incidence of cervical spine involvement. Twenty-five were examined prospectively, including a detailed history and physical examination and cervical spine roentgenograms consisting of an AP and lateral flexion-extension series. All roentgenograms were reviewed by a board-certified radiologist. The mean age of patients in both groups was 25.4 years (range, eight to 54 years). In the retrospective review, no patients were noted to have complaints referable to the cervical spine, although five patients had prior trauma to the cervical spine. In the prospective study, 8 of 25 patients complained of intermittent neck discomfort and 9 of 25 had restricted lateral rotation and/or lateral flexion. No patient had radicular symptoms or objective neurologic deficits. Roentgenograms showed abnormalities in 13 of 25 patients. Ten patients (aged 19 to 54 years; mean, 32 years) showed cystic changes or endplate irregularity within one or more vertebral bodies. Two patients, aged 15 to 19 years, had an increased atlanto-dens interval of 5 mm (normal, 3 mm). No odontoid erosion was noted. No correlation was found between the severity of peripheral involvement and the cervical spine roentgenograms. Occult instability of the cervical spine is discussed, along with ramifications for patients with hemophilia.

    Title Chemonucleolysis. The Relationship of the Physical Findings, Discography, and Myelography to the Clinical Result.
    Date October 1986
    Journal Spine
    Excerpt

    Fifty consecutive patients undergoing chemonucleolysis with chymopapain at William Beaumont Hospital were analyzed with special reference to the following factors: the physical examination, the dye pattern noted on discogram, and the size of the preoperative myelographic defect. Discogram pattern was divided in four types: normal disc, degenerative pattern, degenerative pattern with extravasation, and annular injection. The myelograms were graded into a mild defect, a moderate defect, or a severe defect. Follow-up averaged 20 months. Conclusions of this study were Chymopapain can be considered as an alternative to lumbar laminectomy for relief of sciatica secondary to herniated disc. Statistically significant improved postinjection results were noted when patients presented with three out of four objective physical findings consisting of positive straight leg raising, reflex change, dermatomal paresthesia pattern, and/or mild motor weakness. Placement of the needle within the nucleus leads to a statistically significant improved result over placement of the needle into the annulus. A severe myelographic defect greater than 50% dura sac compression is a relative contraindication to the injection of chymopapain.

    Title Subacute Instability of the Cervical Spine.
    Date September 1984
    Journal Spine
    Excerpt

    The purpose of this article is to describe a new entity, subacute instability of the cervical spine. It is defined as the development of radiographic evidence of cervical instability within 3 weeks of a cervical spine injury when initial adequate roentgenograms show no bony or soft tissue abnormality. Six patients who conform to this definition are reported. Each was found to have developed neurologic deficit and radiographic evidence of instability of the cervical spine on repeat examination when none was present initially. There were four unilateral facet dislocations (two C5-C6, one C6-C7, one C4-C5), one perched facet (C5-C6), and one extension subluxation (C4-C5). The mechanism of subacute instability is thought to be due to the elastic and plastic deformation of the ligamentous structures and discs of the cervical spine. An algorithm has been developed and is described for evaluation of patients with cervical trauma and initial normal radiographs. By alerting physicians to the entity of subacute instability of the cervical spine, it is hoped that injuries of this nature will be discovered so that appropriate treatment can be rendered before a fixed deformity develops.

    Title The Indications for Metrizamide Myelography. Relationship with Complications After Myelography.
    Date December 1983
    Journal The Journal of Bone and Joint Surgery. American Volume
    Excerpt

    To test the validity of our impression that in the absence of objective clinical evidence of nerve-root impingement there is a disproportionately high incidence of complications associated with myelography, the results in 248 patients were reviewed retrospectively and those in 110 were studied prospectively. Of all 358 patients, 53 per cent had complications after myelography with injection of metrizamide, of which headache and nausea and vomiting were the most frequent. The incidence of complications in the 112 patients whose objective clinical and myelographic findings were consistent was compared with that in the 180 patients who had only subjective complaints and normal myelographic findings. The incidence of complications was 30 per cent in the former group and 70 per cent in the latter group, an almost twofold difference (p greater than 0.05). The 110 patients in the prospective study were asked to grade the intensity of their headache after myelography. Of the thirty-one patients with positive objective clinical and myelographic findings, ten complained of headache, which was mild in seven (70 per cent) and severe in three. Of the sixty patients with only subjective complaints, thirty-eight complained of headache, which was mild in twelve (32 per cent) and severe in twenty-six.

    Title Metrizamide Myelography and Epidural Venography. Their Role in the Diagnosis of Lumbar Disc Herniation and Spinal Stenosis.
    Date June 1982
    Journal Spine
    Excerpt

    This study compares lumbar epidural venography with metrizamide (Amipaque) myelography as diagnostic modalities in the evaluation of lumbar disc herniation and spinal stenosis. The accuracy of epidural venography and metrizamide myelography was evaluated in 30 surgically confirmed cases of lumbar disc herniation and spinal stenosis to determine their relative diagnostic values. Sensitivities of epidural venography and metrizamide myelography were 83% and 97%, respectively, while the specificities were 88% and 100%, respectively. The conclusions of this study were: (1) The accuracy of metrizamide myelography exceeds that of epidural venography in the diagnosis of lumbar disc herniation and spinal stenosis. (2) Metrizamide myelography is indicated as the primary contrast technique in lumbar disc herniation and spinal stenosis. (3) Epidural venography is indicated as a secondary contrast technique in patients with a congenitally short or tapered dural sac.

    Title Vertebral Column Injuries Associated with Tobogganing.
    Date March 1979
    Journal The Journal of Trauma
    Excerpt

    Twenty-four cases of vertebral column injuries associated with tobogganing accidents are presented. The position assumed by the participants increased flexion of the vertebral column, therefore enhancing the possibility of injury to the spine, especially at the mobile thoracolumbar junction. The importance of a thorough examination in evaluating these patients is emphasized as not all injuries are benign. We urge safer and better organization of tobogganing facilities. Two case reports, one a burst fracture of L1 with neurologic involvement and the second, a traumatic spondylolisthesis of L1, are presented in detail.

    Title Lumbar Spine Fusion in the Treatment of Degenerative Conditions: Current Indications and Recommendations.
    Date
    Journal The Journal of the American Academy of Orthopaedic Surgeons
    Excerpt

    The role of arthrodesis in the treatment of degenerative disorders of the lumbar spine is controversial. Most patients with these conditions can be successfully treated nonoperatively. Lumbar fusion, with or without instrumentation, is associated with more complications, especially in the elderly population. Therefore, the potential benefits to be obtained by means of arthrodesis must be measured against the risks. Arthrodesis is indicated as an adjunct to decompression for patients with spinal stenosis associated with degenerative or iatrogenic spondylolisthesis and in the treatment of progressive degenerative lumbar scoliosis and iatrogenic instability resulting from extensive decompression. The occurrence of two or more episodes of disk herniation at the same segment is a relative indication for arthrodesis. In patients with incapacitating nonradicular back pain, arthrodesis should be a consideration only after failure of a trial of nonoperative treatment lasting more than 12 months and after secondary gain issues (e.g., workmen's compensation) have been adequately resolved. Arthrodesis has a poor success rate when used to treat back pain associated with multilevel disk degeneration seen on magnetic resonance images.

    Title Educational: Guidelines for Orthopaedic and Neurosurgical Spinal Fellowship Training
    Date
    Journal Spine
    Title Biomimetic Calcium Phosphate Coatings As Bone Morphogenetic Protein Delivery Systems in Spinal Fusion.
    Date
    Journal The Spine Journal : Official Journal of the North American Spine Society
    Excerpt

    BACKGROUND CONTEXT: Use of recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to enhance spinal fusion rates. Case reports of soft-tissue swelling, ectopic bone formation, and osteolysis have recently surfaced. It is hypothesized that incorporation of rhBMP-2 within a calcium phosphate (CaP) coating may help to localize delivery and mitigate these complications. PURPOSE: To compare the characteristics of posterolateral fusion between rabbits receiving rhBMP-2 delivered via physical adsorption to a collagen sponge or rhBMP-2 incorporated within the physical structure of a CaP coating on a collagen sponge. STUDY DESIGN/SETTING: New Zealand white rabbit model of posterolateral lumbar fusion at L5-L6. METHODS: Eighteen (18) New Zealand white rabbits underwent posterolateral spinal fusion at L5-L6. Rabbits received bilateral collagen sponges that were either coated with CaP (n=3), coated with CaP and dipped in rhBMP-2 (n=3), coated with a hybrid CaP-rhBMP-2 film (n=6), or coated with a hybrid CaP-rhBMP-2 film and dipped in rhBMP-2 (n=6). Animals were followed weekly with radiographs and were sacrificed at 6 weeks. Fusion masses were further characterized by manual palpation, computed tomography, and histology. RESULTS: Radiographic evaluation showed that animals in Group 3 (incorporated BMP) fused at 4 weeks, whereas animals in Group 2 (adsorbed BMP) and Group 4 (incorporated and adsorbed BMP) fused by 6 weeks. Animals that received rhBMP-2 physically adsorbed to the collagen sponge showed extension of the fusion mass beyond the L5-L6 level in 56% of cases and bone resorption in 78%. Histology of fusion masses showed mature bone formation in animals belonging to Groups 2, 3, and 4 and extensive osteoclast recruitment in animals belonging to Groups 2 and 4. CONCLUSIONS: Delivery of rhBMP-2 via incorporation within CaP coatings results in increased rates of radiographic fusion. The burst release profile of rhBMP-2 adsorbed to surfaces, although effective in achieving fusion, may result in increased osteoclast recruitment.


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