Surgical Specialist, Orthopaedic Surgeon
9 years of experience
Video profile
Accepting new patients
3000 Colby St
Ste 301
Berkeley, CA 94705
510-540-6800
Locations and availability (4)

Education ?

Medical School Score Rankings
University of North Carolina (2001)
  • Currently 4 of 4 apples
Top 25%

Awards & Distinctions ?

Awards  
Top Ten Doctors (2012)
Orthopedic Surgery, King Charles, Berkeley, CA

Affiliations ?

Dr. Schimizzi is affiliated with 5 hospitals.

Hospital Affilations

Score

Rankings

  • Wake Med Raleigh Campus
    Orthopaedic Surgery
    3000 New Bern Ave, Raleigh, NC 27610
    • Currently 2 of 4 crosses
  • WakeMed Cary Hospital
    Orthopaedic Surgery
    1900 Kildaire Farm Rd, Cary, NC 27518
    • Currently 1 of 4 crosses
  • Alta Bates Summit Medical Center- Summit Campus
    Orthopaedic Surgery
    350 Hawthorne Ave, Oakland, CA 94609
    • Currently 1 of 4 crosses
  • Alta Bates Summit Medical Center - Alta Bates Campus
    Orthopaedic Surgery
    2450 Ashby Ave, Berkeley, CA 94705
    • Currently 1 of 4 crosses
  • Alta Bates Medical Summit Center - Herrick Campus
    2001 Dwight Way, Berkeley, CA 94704
  • Publications & Research

    Dr. Schimizzi has contributed to 4 publications.
    Title High-molecular-weight Hyaluronan Inhibits Macrophage Proliferation and Cytokine Release in the Early Wound of a Preclinical Postlaminectomy Rat Model.
    Date January 2007
    Journal The Spine Journal : Official Journal of the North American Spine Society
    Excerpt

    BACKGROUND CONTEXT: Failed back syndrome, a condition that affects 3-14% of postoperative spine patients, is characterized by the recurrence of radicular pain after spinal decompression. The source of this pain in some patients is thought by many investigators to be the result of epidural scarring and nerve root tethering, but this is controversial. We have previously demonstrated that in a disc-injury model the untreated postlaminectomy rats develop a significant proliferative fibrous response at 8 weeks with spinal nerve scarring to the disc and adjacent pedicle, and increased sensitivity to tactile allodynia testing in the related sensory dermatome. Topical high-molecular-weight hyaluronan (HMW HA) moderates both the proliferative fibrosis and the behavioral pain response. PURPOSE: Our purpose is to study the time-related changes in the proinflammatory cytokine and monocyte/macrophage profiles in the epidural space in the early postlaminectomy untreated and HMW HA gel treated groups. STUDY DESIGN/SETTING: A modified rat laminectomy with disc injury model was employed to assess epidural fibrosis between and around the spinal nerves using a quantitative immunohistochemistry assessment approach along with correlative enzyme-linked immunosorbent assay analysis. METHODS: Lumbar laminectomies at L5 and L6 with a L5-L6 disc injury were performed on 120 adult male Sprague-Dawley rats. The rats were then randomized into one of two groups: untreated and treated. The treatment group received a one-time topical application of 0.1 cc of HMW HA gel directly to the laminectomy site just before wound closure. The rats were then randomly subdivided into survival periods of 24 hours, 72 hours, and 7 days. Immunohistochemistry was performed on fresh frozen sections and stained for interleukin-1 beta (IL-1beta) and monocytes/macrophages (ED-1) using monoclonal antibodies and 3, 3' diaminobenzidine (DAB) chromogen. The amount of stain in each specimen was then quantified using the National Institutes of Health computer imaging analysis system. RESULTS: The semiquantified data from the histological specimens demonstrated significant decreases in the IL-1beta and IL-6 infiltration observed at 24 hours in the epidural space and around the right nerve root (p=.0296 and 0.0195, respectively) in the HA gel treated group. Additionally, significant decreases in the monocyte/macrophage infiltration were observed at 72 hours in the epidural space around the left nerve root (p=.0039) and right nerve root (p=.0072) in the HA gel treated group. At 7 days, IL-1beta, IL-6, and macrophage infiltration of the wound had declined in both the HA gel and the untreated groups. The enzyme-linked immunosorbent assay data support the same pattern as seen in the histological results. CONCLUSION: These results demonstrate that treatment of postlaminectomy wounds with HMW HA gel decreases the number of monocytes and macrophages and the concentration of certain cytokines in the early inflammatory phase of healing. There are several plausible explanations for this effect. First, the HMW HA may block the interaction of short-chain low-molecular-weight HA with proinflammatory cell surface receptors. The interaction of these short-chain oligo-HA fragments, upon cell-surface receptor binding, induces changes in inflammatory cells that lead to increased cell motility and migration into the wound area. Second, the addition of exogenous HMW HA may cause a dilution effect in the wound, thereby decreasing the concentration of inflammatory cells in the extracellular matrix of the region of injury. Finally, the migration of inflammatory cells may be decreased in the viscous environment of the HMW HA. The first explanation is believed by the authors of this paper to be the more likely mechanism. HMW HA probably mutes the proinflammatory effects of the low-molecular weight fragments, leading to decreased inflammation, and thus decreased fibrosis and scar formation noted in the chronic model.

    Title Acute Compartment Syndrome Due to Ruptured Baker Cyst After Nonsurgical Management of an Anterior Cruciate Ligament Tear: a Case Report.
    Date August 2006
    Journal The American Journal of Sports Medicine
    Title Paraspinal Muscle Vasculature Contributes to Posterolateral Spinal Fusion.
    Date August 2006
    Journal Spine
    Excerpt

    STUDY DESIGN: Study of posterolateral fusions in a rabbit model. OBJECTIVES: To characterize the contribution of paraspinal musculature to the healing of posterolateral spinal fusions in a rabbit model. SUMMARY OF BACKGROUND DATA: Previous studies have demonstrated that successful spinal arthrodesis requires vascular ingrowth from adjacent decorticated bone. In other areas of the body, such as the tibia, vascular ingrowth from the surrounding musculature has also been shown to be important. The role of the surrounding paraspinal musculature in spinal fusions has yet to be assessed. METHODS: Twenty-five New Zealand white rabbits underwent posterolateral spinal fusion. One side of the animals was treated with autograft alone and served as the control group. On the contralateral side, the autograft was contained within porous or nonporous barrier sheets. Following euthanization, high-resolution radiographs, CT scans, and histologic analyses were performed to assess fusion and characterize vascular ingrowth. RESULTS: Using histologic evaluation, the fusion rate in the porous group was 90%, in the nonporous group 40%, and in the control group 55%. Vascular ingrowth was evident from the muscle through the porous sheet into the fusion mass. CONCLUSIONS: These results support our hypothesis that the paraspinal musculature provides important vascular ingrowth into the fusion site. Use of a porous barrier sheet appears to improve fusion by preventing muscle interposition while allowing vascular ingrowth from surrounding muscle.

    Title Topical High Molecular Weight Hyaluronan Reduces Radicular Pain Post Laminectomy in a Rat Model.
    Date January 2006
    Journal The Spine Journal : Official Journal of the North American Spine Society
    Excerpt

    BACKGROUND CONTEXT: A controversy exists about the mechanism of causation of the post-laminectomy pain syndrome. Some believe that epidural scarring, and attendant spinal nerve and nerve root scarring and tethering to the disc or pedicle at the site of surgery contributes to post-laminectomy pain in such patients. However, clinical outcome studies on this question are inconclusive and the assertion remains controversial. Definitive studies to help resolve the question are needed. Previously our laboratory has reported on a preclinical post-laminectomy model that mimics the postoperative proliferative fibrotic response grossly, as well as by biochemical assessment of the collagen content within the spinal canal. The post-laminectomy fibrotic response was attenuated in that study by application of a topical antifibrotic (high molecular weight hyaluronan gel) or by insertion of an absorbable roofing barrier (0.2-mm-thick Macropore sheet material) over the laminectomy defect before wound closure. The question remains of relevance of the attenuation of the fibrotic response to post-laminectomy chronic pain syndromes. PURPOSE: The purpose of this study is to evaluate the effect of therapeutic attenuation of proliferative scar within the spinal canal post laminectomy on the pain-related behavioral response in a preclinical rat model. STUDY DESIGN/SETTING: An established L5-L6 rat laminectomy model with a unilateral L5-6 disc injury was employed to assess postoperative proliferative fibrosis of the L5 spinal nerves using quantitative biochemical hydroxyproline assessment of the collagen content in four experimental groups. These observations were correlated with gross descriptions of spinal nerve scarring or tethering. Associated manifestations of a sensory pain-related response in the L5 spinal nerve receptor area of the hind paws was studied using standard tactile allodynia assessment with the von Frey hair technique. The tactile allodynia findings were supplemented by weekly descriptors of behavioral pain manifestations. METHODS: Bilateral laminectomies at L5 and L6 and a unilateral right disc injury (L5-6) were performed on 35 male adult Sprague-Dawley rats, weighing 400+ grams (approved by the VA Institutional Animal Care Use Committee). The study consisted of four groups: 1) normal nonoperative control; 2) a sham-operated group; 3) an untreated laminectomy-disc injury group; and 4) a laminectomy-disc injury treatment group in which 0.1 cc topical high molecular weight hyaluronan (HMW HA) gel was layered over the dura and into the laminectomy canal before closure. Before animals were entered into the study, they were checked for the presence of abnormal response to the tactile testing procedure of the L5 sensory receptor area. Animals exhibiting anomalous responses were excluded from the study. Behavioral testing for tactile allodynia was performed at weekly intervals post laminectomy beginning at 3 weeks. Pain-related behavior was characterized at weekly intervals. A behavioral test cage with a wire mesh floor allowed for tactile allodynia testing. Graduated von Frey hairs whose stiffness increased logarithmically from 0.41 to 15 g were used for tactile allodynia tests. The animals were killed 8 weeks postoperatively for analysis. The dissected spinal nerve and nerve root specimens were studied biochemically for hydroxyproline content to estimate total collagen in and around the L5 neural structures. Statistical analyses were performed using analysis of variance and a Fisher comparison t test. RESULTS: The major observations on the untreated preclinical post-laminectomy rat model previously described by this laboratory were confirmed. All untreated animals developed a tail contracture concave toward the right (disc injury side) consistent with asymmetrical lumbar muscle spasm. Only one animal in the HA gel treatment group had a tail contracture. It was of mild degree and occurred in an animal that demonstrated slightly increased right L5 tactile sensitivity. Gross inspection of the dissected specimens demonstrated spinal nerve scarring and tethering to the disc and pedicle greater on the right than the left in untreated animals, findings that were markedly reduced in the treatment group. Collagen content of the L5 spinal nerve and nerve roots with attached scar were significantly lower in the HA gel treatment group than in the untreated laminectomy group (p=.0014). Pain behavioral testing of the L5 receptor area of the right hind paw in the untreated laminectomy group showed markedly increased sensitivity to tactile allodynia testing compared with the corresponding limb of the control group (p=.0001), to the corresponding limb of the sham group (p=.0001), and compared with the HMW HA gel treatment group (p=.0010). Comparisons of the pain behavioral data between the sham and the post-laminectomy HA gel treatment group and the control animals lacked statistical significance. CONCLUSION: This study supports the concept of a relationship between perineural fibrosis and radicular neuropathy in the model described, and emphasizes the role of disc injury and spinal nerve retraction in the post-laminectomy fibrotic process. Furthermore, it shows promise for preliminary assessment of interventions with other anti-inflammatory agents, for characterization of the neurochemical profile of the post-laminectomy pain state, and for exploration of newer pharmaceutical agents potentially useful in the prevention or management of the post-laminectomy syndrome. Post-laminectomy scar is but one of many potential causes of the post-laminectomy pain syndrome. Furthermore, a cautionary note must be emphasized as in all studies using preclinical models, conclusions drawn from the studies cannot be extended directly to patients without confirmatory clinical follow-up studies.

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