Sohail K Mirza

Dartmouth–Hitchcock Medical Center, LEB, New Hampshire, United States

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Publications (128)457.42 Total impact

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    Sohail K Mirza

    Preview · Article · Jan 2016 · Evidence-Based Medicine
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    ABSTRACT: Study design: Analysis of the State Inpatient Database of North Carolina, 2005-2012, and the Nationwide Inpatient Sample, including all inpatient lumbar fusion admissions from non-federal hospitals. Objective: To examine the influence of a major commercial policy change that restricted lumbar fusion for certain indications, and to forecast the potential impact if the policy were adopted nationally. Summary of background data: Few studies have examined the effects of recent changes in commercial coverage policies that restrict the use of lumbar fusion. Methods: We included adults undergoing elective lumbar fusion or re-fusion operations in North Carolina. We aggregated data into a monthly time series to report changes in the rates and volume of lumbar fusion operations for disc herniation or degeneration, spinal stenosis, spondylolisthesis, or revision fusions. Time series regression models were used to test for significant changes in the use of fusion operation following a major commercial coverage policy change initiated on January 1st, 2011. Results: There was a substantial decline in the use of lumbar fusion for disc herniation or degeneration following the policy change on January 1st, 2011. Overall rates of elective lumbar fusion operations in North Carolina (per 100,000 residents) increased from 103.2 in 2005 to 120.4 in 2009, before declining to 101.9 by 2012. The population rate (per 100,000 residents) of fusion among those under age 65 increased from 89.5 in 2005 to 101.2 in 2009, followed by a sharp decline to 76.8 by 2012. There was no acceleration in the already increasing rate of fusion for spinal stenosis, spondylolisthesis or revision procedures, but there was a coincident increase in decompression without fusion. Conclusions: This commercial insurance policy change had its intended effect of reducing fusion operations for indications with less evidence of effectiveness without changing rates for other indications or resulting in an overall reduction in spine surgery. Nevertheless, broader adoption of the policy could significantly reduce the national rates of fusion operations and associated costs. Level of evidence: 3.
    No preview · Article · Dec 2015 · Spine
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    ABSTRACT: An accurate and reliable benchmark of registration accuracy and intervertebral motion compensation is important for spinal image guidance. In this study, we evaluated the utility of intraoperative CT (iCT) in place of bone-implanted screws as the ground-truth registration and illustrated its use to benchmark the performance of intraoperative stereovision (iSV). A template-based, multi-body registration scheme was developed to individually segment and pair corresponding vertebrae between preoperative CT and iCT of the spine. Intervertebral motion was determined from the resulting vertebral pair-wise registrations. The accuracy of the image-driven registration was evaluated using surface-to-surface distance error (SDE) based on segmented bony features and was independently verified using point-to-point target registration error (TRE) computed from bone-implanted mini-screws. Both SDE and TRE were used to assess the compensation accuracy using iSV. The iCT-based technique was evaluated on four explanted porcine spines (20 vertebral pairs) with artificially induced motion. We report a registration accuracy of 0.57 [Formula: see text] 0.32 mm (range 0.34-1.14 mm) and 0.29 [Formula: see text] 0.15 mm (range 0.14-0.78 mm) in SDE and TRE, respectively, for all vertebrae pooled, with an average intervertebral rotation of [Formula: see text] (range 1.5[Formula: see text]-7.9[Formula: see text]). The iSV-based compensation accuracy for one sample (four vertebrae) was 1.32 [Formula: see text] 0.19 mm and 1.72 [Formula: see text] 0.55 mm in SDE and TRE, respectively, exceeding the recommended accuracy of 2 mm. This study demonstrates the effectiveness of iCT in place of invasive fiducials as a registration ground truth. These findings are important for future development of on-demand spinal image guidance using radiation-free images such as stereovision and ultrasound on human subjects.
    Preview · Article · Jul 2015 · International Journal of Computer Assisted Radiology and Surgery
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    ABSTRACT: Despite its widespread availability and success in open cranial neurosurgery, image-guidance technology remains more limited in use in open spinal procedures, in large part because of patient registration challenges. In this study, we evaluated the feasibility of using intraoperative stereovision (iSV) for accurate, efficient and robust patient registration in open spinal fusion surgery. Geometrical surfaces of exposed vertebrae were first reconstructed from iSV. A classical multi-start registration was then executed between point clouds generated from iSV and preoperative CT (pCT) images of the spine. With two pairs of feature points manually identified to facilitate the registration, an average registration accuracy of 1.43 mm in terms of surface-to-surface distance error was achieved in 8 patient cases using a single iSV image pair sampling 2-3 vertebral segments. The iSV registration error was consistently smaller than the conventional landmark approach for every case (average of 2.02 mm with the same error metric). The large capture ranges (average of 23.8 mm in translation and 46.0 deg in rotation) found in the iSV patient registration suggest the technique may offer sufficient robustness for practical application in the operating room. Although some manual effort was still necessary, the manually-derived inputs for iSV registration only needed to be approximate as opposed to be precise and accurate for the manual efforts required in landmark registration. The total computational cost of the iSV registration was 1.5 min on average, significantly less than the typical ~30 min required for the landmark approach. These findings support the clinical feasibility of iSV to offer accurate, efficient and robust patient registration in open spinal surgery, and therefore, its potential to further increase the adoption of image-guidance in this surgical specialty.
    No preview · Article · Mar 2015 · IEEE transactions on bio-medical engineering
  • Article: SPORT

    No preview · Article · Mar 2015 · Neurosurgery
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    ABSTRACT: Use of Bone Morphogenetic Protein (BMP) as an adjunct to spinal fusion surgery proliferated following Food and Drug Administration (FDA) approval in 2002. Major safety concerns emerged in 2008. To examine whether published concerns about the safety of BMP altered clinical practice. Analysis of the National Inpatient Sample from 2002 through 2012. Adults (age >20) undergoing an elective fusion operation for common degenerative diagnoses, identified using codes from the International Classification of Diseases, 9(th)revisions, Clinical Modification (ICD-9-CM). Proportion of cervical and lumbar fusion operations, over time, that involved BMP. We aggregated the data into a monthly time series and reported the proportion of cervical and lumbar fusion operations, over time, that involved BMP. Auto Regressive Integrated Moving Average, a regression model for time series data, was used to test whether there was a statistically significant change in the overall rate of BMP use following a FDA Public Health Notification in 2008. The study was funded by federal research grants, and no investigator had any conflict of interests. Use of BMP in spinal fusion procedures increased rapidly until 2008, involving up to 45.2% of lumbar and 13.5% of cervical fusions. BMP use significantly decreased following the 2008 FDA Public Health Notification and revelations of financial payments to surgeons involved in the pivotal FDA approval trials. For lumbar fusion, the average annual increase was 7.9 percentage points per year from 2002 to 2008, followed by an average annual decrease of 11.7 percentage points thereafter (p = <0.001). Use of BMP in cervical fusion increased 2.0% per year until the FDA Notification, followed by a 2.8% per year decrease (p = 0.035). Use of BMP in spinal fusion surgery declined subsequent to published safety concerns and revelations of financial conflicts-of-interest for investigators involved in the pivotal clinical trials. Copyright © 2014 Elsevier Inc. All rights reserved.
    Full-text · Article · Dec 2014 · The spine journal: official journal of the North American Spine Society
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    Full-text · Chapter · Oct 2014
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    ABSTRACT: Background: The Spine Patient Outcomes Research Trial aimed to determine the comparative effectiveness of surgical care versus nonoperative care by measuring longitudinal values: outcomes, satisfaction, and costs. Methods: This paper aims to summarize available evidence from the Spine Patient Outcomes Research Trial by addressing 2 important questions about outcomes and costs for 3 types of spine problem: (1) how do outcomes and costs of spine patients differ depending on whether they are treated surgically compared with nonoperative care? (2) What is the incremental cost per quality adjusted life year for surgical care over nonoperative care? Results: After 4 years of follow-up, patients with 3 spine conditions that may be treated surgically or nonoperatively have systematic differences in value endpoints. The average surgical patient enjoys better health outcomes and higher treatment satisfaction but incurs higher costs. Conclusions: Spine care is preference sensitive and because outcomes, satisfaction, and costs vary over time and between patients, data on value can help patients make better-informed decisions and help payers know what their dollars are buying.
    No preview · Article · Oct 2014 · Medical care
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    Full-text · Dataset · Apr 2014
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    ABSTRACT: Safety information in spine surgery is important for informed patient choice and performance-based payment incentives, but measurement methods for surgical safety assessment are not standardized. Published reports of complication rates for common spinal procedures show wide variation. Factors influencing variation may include differences in safety ascertainment methods and procedure types. In a prospective cohort study, adverse events were observed in all patients undergoing spine surgery at two hospitals during a 2-year period. Multiple processes for adverse occurrence surveillance were implemented, and the associations between surveillance methods, surgery invasiveness, and observed frequencies of adverse events were examined. The study enrolled 1,723 patients. Adverse events were noted in 48.3% of the patients. Reviewers classified 25% as minor events and 23% as major events. Of the major events, the daily rounding team reported 38.4% of the events using a voluntary reporting system, surgeons reported 13.4%, and 9.1% were identified during clinical conferences. A review of medical records identified 86.7% of the major adverse events. The adverse events occurred during the inpatient hospitalization for 78.1% of the events, within 30 days for an additional 12.5%, and within the first year for the remaining 9.4%. A unit increase in the invasiveness index was associated with an 8.2% increased risk of a major adverse event. A Current Procedural Terminology-based algorithm for quantifying invasiveness correlated well with medical records-based assessment. Increased procedure invasiveness is associated with an increased risk of adverse events. The observed frequency of adverse events is influenced by the ascertainment modality. Voluntary reports by surgeons and other team members missed more than 50% of the events identified through a medical records review. Increased surgery invasiveness, measured from medical records or billing codes, is quantitatively associated with an increased risk of adverse events.
    Full-text · Article · Apr 2014 · Instructional course lectures
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    ABSTRACT: Study Design. Retrospective analysis of Medicare claims linked to a multi-center clinical trial.Objective. The Spine Patient Outcomes Research Trial (SPORT) provided a unique opportunity to examine the validity of a claims-based algorithm for grouping patients by surgical indication. SPORT enrolled patients for lumbar disc herniation, spinal stenosis, and degenerative spondylolisthesis. We compared the surgical indication derived from Medicare claims to that provided by SPORT surgeons, the "gold standard".Summary of Background Data. Administrative data are frequently used to report procedure rates, surgical safety outcomes, and costs in the management of spinal surgery. However, the accuracy of using diagnosis codes to classify patients by surgical indication has not been examined.Methods. Medicare claims were link to beneficiaries enrolled in SPORT. The sensitivity and specificity of three claims-based approaches to group patients based on surgical indications were examined: 1) using the first listed diagnosis; 2) using all diagnoses independently; and 3) using a diagnosis hierarchy based on the support for fusion surgery.Results. Medicare claims were obtained from 376 SPORT participants, including 21 with disc herniation, 183 with spinal stenosis, and 172 with degenerative spondylolisthesis. The hierarchical coding algorithm was the most accurate approach for classifying patients by surgical indication, with sensitivities of 76.2%, 88.1%, and 84.3% for disc herniation, spinal stenosis, and degenerative spondylolisthesis cohorts, respectively. The specificity was 98.3% for disc herniation, 83.2% for spinal stenosis, and 90.7% for degenerative spondylolisthesis. Misclassifications were primarily due to codes attributing more complex pathology to the case.Conclusion. Standardized approaches for using claims data to accurately group patients by surgical indications has widespread interest. We found that a hierarchical coding approach correctly classified over 90% of spine patients into their respective SPORT cohorts. Therefore, claims data appears to be a reasonably valid approach to classifying patients by surgical indication.
    Full-text · Article · Apr 2014 · Spine (Philadelphia, Pa.: 1986)
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    ABSTRACT: Study Design. Retrospective analysis of Medicare claims linked to a multi-center clinical trial.Objective. The Spine Patient Outcomes Research Trial (SPORT) provided a unique opportunity to examine the validity of a claims-based algorithm for grouping patients by surgical indication. SPORT enrolled patients for lumbar disc herniation, spinal stenosis, and degenerative spondylolisthesis. We compared the surgical indication derived from Medicare claims to that provided by SPORT surgeons, the "gold standard".Summary of Background Data. Administrative data are frequently used to report procedure rates, surgical safety outcomes, and costs in the management of spinal surgery. However, the accuracy of using diagnosis codes to classify patients by surgical indication has not been examined.Methods. Medicare claims were link to beneficiaries enrolled in SPORT. The sensitivity and specificity of three claims-based approaches to group patients based on surgical indications were examined: 1) using the first listed diagnosis; 2) using all diagnoses independently; and 3) using a diagnosis hierarchy based on the support for fusion surgery.Results. Medicare claims were obtained from 376 SPORT participants, including 21 with disc herniation, 183 with spinal stenosis, and 172 with degenerative spondylolisthesis. The hierarchical coding algorithm was the most accurate approach for classifying patients by surgical indication, with sensitivities of 76.2%, 88.1%, and 84.3% for disc herniation, spinal stenosis, and degenerative spondylolisthesis cohorts, respectively. The specificity was 98.3% for disc herniation, 83.2% for spinal stenosis, and 90.7% for degenerative spondylolisthesis. Misclassifications were primarily due to codes attributing more complex pathology to the case.Conclusion. Standardized approaches for using claims data to accurately group patients by surgical indications has widespread interest. We found that a hierarchical coding approach correctly classified over 90% of spine patients into their respective SPORT cohorts. Therefore, claims data appears to be a reasonably valid approach to classifying patients by surgical indication.
    No preview · Article · Feb 2014 · Spine
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    ABSTRACT: In response to increasing use of lumbar fusion for improving back pain, despite unclear efficacy, particularly among injured workers, some insurers have developed limited coverage policies. Washington State's workers' compensation (WC) program requires imaging confirmation of instability and limits initial fusions to a single level. In contrast, California requires coverage if a second opinion supports surgery, allows initial multilevel fusion, and provides additional reimbursement for surgical implants. There are no studies that compare population-level effects of these policy differences on utilization, costs, and safety of lumbar fusion.
    Full-text · Article · Nov 2013 · The spine journal: official journal of the North American Spine Society
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    ABSTRACT: Purpose: There is no universally accepted standard of care for lumbar spinal stenosis. Several studies suggest surgical care results in better outcomes than conservative care, but the type of surgery (decompression vs. fusion) remains controversial. Interspinous spacer devices (“spacers”) have emerged as a new initial treatment alternative. Our objective was to assess the cost-effectiveness of spacers for lumbar stenosis and to identify thresholds for post-spacer health utility that would result in spacers being a cost-effective initial surgery. Method: A Markov model tracked health utility and costs for a hypothetical 65-year-old cohort followed over a 10-year time horizon under six care strategies: conservative care (C) and five surgical strategies defined by initial and up to two subsequent surgeries involving spacer (S), decompression (D), and/or fusion (F): S-D-D, S-D-F, S-F-F, D-D-F, and D-F-F. Incremental cost-effectiveness ratios (ICER) reported as cost per quality-adjusted life year (QALY) gained included direct medical costs for surgery (initial S: $8,227; D: $5,925; F: $20,101). Medicare claims data were used to estimate costs, complication rates (S: 4.8%; D: 6.6%; F: 9.4%) and reoperation within 3 years (S: 20.1%; D: 10.8%; F: 14%) for each surgery. Utilities were derived from published studies (C:0.71; S: 0.82; D: 0.77; F:0.74). Reoperation rates after 3 years for D and F were obtained from the literature. Spacer failure beyond 3 years is uncertain and was evaluated through sensitivity analyses. In the base-case, the spacer failure rate was held constant for years 4-10 (cumulative: 47%). In subsequent analyses, the 10-year failure rate was increased either moderately (to 56%) or steeply (to 90%). Additionally, since utility following spacer surgery is rarely reported, we performed threshold analyses on post-spacer utility to determine when spacer surgery fails to be cost-effective either because it is dominated or has an ICER> $100,000. Result: An initial spacer strategy (S-D-D) emerged as the most cost-effective ($14,400 per QALY gained) in base-case analyses. The ICER rose minimally ($16,800) when the failure rate was increased steeply. Spacer surgery remained cost-effective for post-spacer utilities ≥0.7695 in the base case and ≥0.773 under steeply increased failure. Conclusion: Post-spacer health utilities in the literature to date exceed the identified thresholds, suggesting that interspinous spacer devices are reasonably cost-effective when implemented as a first surgical intervention for patients with spinal stenosis.
    No preview · Conference Paper · Oct 2013
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    ABSTRACT: The clinical entity "discogenic back pain" remains controversial at fundamental levels, including its pathophysiology, diagnostic criteria, and optimal treatment. This is true despite availability of four randomized trials comparing the efficacy of surgical and nonsurgical treatments. One trial showed benefit for lumbar fusion compared with unstructured nonoperative care, and three others showed roughly similar results for lumbar surgery and structured rehabilitation. To compare outcomes of community-based surgical and nonsurgical treatments for patients with chronic back pain attributed to degeneration at one or two lumbar disc levels. Prospective observational cohort study. Patients presenting with axial back pain to academic and private practice orthopedic surgeons and neurosurgeons in a large metropolitan area. Roland-Morris back disability score (primary outcome), current rating of overall pain severity on a numerical scale, back and leg pain bothersomeness measures, the physical function scale of the short-form 36 version 2 questionnaire, use of medications for pain, work status, emergency department visits, hospitalizations, and further surgery. Patients receiving spine surgery within 6 months of enrollment were designated as the "surgical treatment" group and the remainder as "nonsurgical treatment." Outcomes were assessed at 3, 6, 9, and 12 months after enrollment. We enrolled 495 patients with discogenic back pain presenting for initial surgical consultation in offices of 16 surgeons. Eighty-six patients (17%) had surgery within 6 months of enrollment. Surgery consisted of instrumented fusion (79%), disc replacement (12%), laminectomy, or discectomy (9%). Surgical patients reported more severe pain and physical disability at baseline and were more likely to have had prior surgery. Adjusting for baseline differences among groups, surgery showed a limited benefit over nonsurgical treatment of 5.4 points on the modified (23-point) Roland disability questionnaire (primary outcome) 1 year after enrollment. Using a composite definition of success incorporating 30% improvement in the Roland score, 30% improvement in pain, no opioid pain medication use, and working (if relevant), the 1-year success rate was 33% for surgery and 15% for nonsurgical treatment. The rate of reoperation was 11% in the surgical group; the rate of surgery after treatment designation in the nonsurgical group was 6% at 12 months after enrollment. The surgical group showed greater improvement at 1 year compared with the nonsurgical group, although the composite success rate for both treatment groups was only fair. The results should be interpreted cautiously because outcomes are short term, and treatment was not randomly assigned. Only 5% of nonsurgical patients received cognitive behavior therapy. Nonsurgical treatment that patients received was variable and mostly not compliant with major guidelines.
    Full-text · Article · Jul 2013 · The spine journal: official journal of the North American Spine Society
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    ABSTRACT: Study Design. A prospective analysis Objective. Our aim was to investigate the efficacy of new synthetic porous/dense composite hydroxyapatite (HA) for use in anterior cervical discectomy and fusion (ACDF). Summary of Background Data. Iliac crest bone graft (ICBG) has been traditionally used as the “gold standard” for ACDF. The significant complication rate associated with harvesting tricortical ICBG, however, has encouraged development of alternative graft substitutes. Methods. The morphology of the porous/dense HA was observed by scanning electron microscopy (SEM), and the in vitro compressive strength of the composite HA was measured. From April 2005, 51 consecutive patients underwent 81 levels of ACDF using the composite HA with percutaneously harvested trephine bone chips. Clinical and radiological evaluation was performed during the postoperative hospital stay and at follow-up. Furthermore, the outcomes in ACDF using the composite HA were compared with those using tricortical ICBG. Results. The SEM images demonstrated 100- to 300-μm pores (approximately 40% of porosity) in the porous layers of the HA. The compressive strength of the composite HA was 203.1 ± 4.1 MPa. In the clinical study, the demographic data of the patients were similar in HA and ICBG groups. The fusion rates in HA group were comparable with those in ICBG group. The cervical lordosis was enhanced postoperatively in both groups and well preserved at 2-year follow-up without significant differences between the groups. The intraoperative blood loss in HA group was significantly lesser than that in ICBG group. Donor site complications were found in 29.2% of the patients in ICBG group, whereas no donor site morbidity was found in HA group. No major collapse or fragmentation of the composite HA was found. Conclusion. The hybrid graft of composite HA and percutaneously harvested trephine chips seemed promising as a graft substitute for ACDF. Level of Evidence: 4
    Full-text · Article · Jan 2013 · Spine
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    ABSTRACT: Purpose: Treatment options for lumbar spinal stenosis include surgical and non-surgical approaches. Decision support in the form of coaching may help patients deliberate about their treatment options. The goal of this study is to assess the impact of coaching on the decision process for patients considering their treatment options for spinal stenosis. Method: Patients with spinal stenosis referred by a spine specialist for decision support are randomly assigned to either: decision aid (DA only, usual care) or decision aid + health coaching by telephone (DA+HC, intervention group). Enrolled participants complete questionnaires at: baseline, after watching the video decision aid, at two weeks after DA, and at 6 months. Measures - patient demographic characteristics (age, gender, and education), stage of decision making, treatment choice, treatments received, and decisional regret. Result: To date, 117 participants have completed baseline and follow up questionnaires (58 DA only / 59 DA+HC). Average age 67.1 years, 49% female, 60% had at least some college. Both groups showed similar progress in decision making after watching the DA (Table 1). More patients in the coaching group had made a treatment decision at the two week follow up (DA+HC 75% vs. DA only 48%, p=0.001). The uptake of surgery was similar for both groups (DA only (11/58 - 19%) had surgery vs. DA+HC (12/59 - 20%); however at the 6 month follow-up point more coaching participants had implemented the treatment chosen at 2 weeks (64% of DA only participants followed through with their choice vs. 80% of DA+HC patients, p=0.03). Few patients indicated regret about their treatment (DA only, 5% vs. DA+HC 7%) at 6-month follow up. Conclusion: The preliminary results from this ongoing study suggest similar treatment uptake and low levels of regret with treatment choice for both study groups. The addition of a telephone coaching session appears to help some participants arrive at a decision more quickly and follow through with their chosen option.
    No preview · Conference Paper · Oct 2012
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    ABSTRACT: Study Design. Retrospective review of a prospectively collected databaseObjective. To examine whether short- and long-term outcomes after surgery for SPS and DS vary across centers.Summary of Background Data. Surgery has been shown to be of benefit for both lumbar stenosis (SPS) and degenerative spondylolisthesis (DS). For both conditions, surgery often consists of laminectomy with or without fusion. Potential differences in outcomes of these overlapping procedures across various surgical centers have not yet been investigated.Methods. Spine Patient Outcomes Research Trial cohort participants with a confirmed diagnosis of SPS or DS undergoing surgery were followed from baseline at 6 weeks, and 3, 6 and 12 months, and yearly thereafter, at 13 spine clinics in 11 US states. Baseline characteristics and short- and long-term outcomes were analyzed.Results. 793 patients underwent surgery. Significant differences were found between centers with regard to patient race, body mass index, treatment preference, neurological deficit, stenosis location, severity and number of stenotic levels. Significant differences were also found in operative duration and blood loss, the incidence of durotomy, the length of hospital stay, and wound infection. When baseline differences were adjusted for, significant differences were still seen between centers in changes in patient functional outcome (SF-36 bodily pain and physical function, and Oswestry disability index) at 1 year after surgery. In addition, the cumulative adjusted change in Oswestry disability index score at 4 years significantly differed among centers, with SF-36 scores trending towards significance.Conclusions. There is broad and statistically significant variation in short- and long-term outcomes after surgery for SPS and DS across various academic centers, when statistically significant baseline differences are adjusted for. The findings suggest choice of center affects outcome after these procedures, although further studies are required to investigate which center characteristics are most important.
    No preview · Article · Oct 2012 · Spine
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    Full-text · Article · Sep 2012 · The Spine Journal
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    ABSTRACT: : Surgery has been shown to be of benefit for both lumbar stenosis and degenerative spondylolisthesis. For both conditions, surgery often consists of laminectomy with or without fusion. Potential differences in outcomes of these overlapping procedures across various surgical centers have not yet been investigated. : Spine Patient Outcomes Research Trial cohort participants with spinal stenosis (SPS) or degenerative spondylolisthesis (DS) undergoing first-time open lumbar laminectomy with or without fusion were followed from baseline at 6 weeks, and 3, 6 and 12 months, and yearly thereafter, at 13 spine clinics in 11 US states. Mean (SD) follow-up was 45.2 (13.8) months. Median (range) follow-up was 47.4 (1.2, 95.6) months. Baseline characteristics, perioperative events and short- and long-term outcomes were analyzed across the centers. : 793 patients underwent surgery. Significant differences were found across centers in operative duration and blood loss, incidence of durotomy, length of hospital stay, and wound infection. There were no significant differences between centers in incidence of nerve root injury or post-operative mortality. Significant differences were seen in the adjusted change in all indices of functional outcome (SF-36 BP and PF, and Oswestry disability index) at 1 year after surgery and in cumulative adjusted change in ODI score at 4 years. : There is broad and statistically significant variation in outcomes after surgery for SPS and DS across various academic centers, when baseline differences are adjusted for. The findings suggest choice of center affects outcome after these procedures, although further studies are required to investigate which center characteristics are most important.
    No preview · Article · Aug 2012 · Neurosurgery

Publication Stats

5k Citations
457.42 Total Impact Points

Institutions

  • 2009-2015
    • Dartmouth–Hitchcock Medical Center
      • Department of Surgery
      LEB, New Hampshire, United States
  • 2009-2014
    • Geisel School of Medicine at Dartmouth
      • Department of Orthopaedics
      Hanover, New Hampshire, United States
  • 2000-2012
    • University of Washington Seattle
      • • Department of Orthopaedics and Sports Medicine
      • • Department of Health Services
      • • Department of Medicine
      • • Department of Neurological Surgery
      • • Department of Mechanical Engineering
      Seattle, WA, United States
  • 2011
    • Dartmouth College
      Hanover, New Hampshire, United States
  • 2007
    • University of California, Davis
      • Department of Family and Community Medicine
      Davis, CA, United States
    • University of California, San Francisco
      San Francisco, California, United States
  • 2006
    • Center for Sports Medicine and Orthopaedics
      Chattanooga, Tennessee, United States
  • 2002
    • University of Louisville
      • Department of Radiology
      Louisville, KY, United States