Sohail K Mirza

Dartmouth College, Hanover, New Hampshire, United States

Are you Sohail K Mirza?

Claim your profile

Publications (96)323.93 Total impact

  • Source
  • Source
    [Show abstract] [Hide abstract]
    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.
    Spine (Philadelphia, Pa.: 1986) 04/2014;
  • [Show abstract] [Hide abstract]
    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.
    Spine 02/2014; · 2.16 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Instructional course lectures 01/2014; 63:271-86.
  • Source
    [Show abstract] [Hide abstract]
    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. The purpose of this study was to compare population-level data on the use of complex fusion techniques, adverse outcomes within 3 months, and costs for two states with contrasting coverage policies. The study design was an analysis of WC patients in California and Washington using the Agency for Healthcare Research and Quality's State Inpatient Databases, 2008-2009. All patients undergoing an inpatient lumbar fusion for degenerative disease (n=4,628) were included the patient sample. Outcome measures included repeat lumbar spine surgery, all-cause readmission, life-threatening complications, wound problems, device complications, and costs. Log-binomial regressions compared 3-month complications and costs between states, adjusting for patient characteristics. Overall rate of lumbar fusion operations through WC programs was 47% higher in California than in Washington. California WC patients were more likely than those in Washington to undergo fusion for controversial indications, such as nonspecific back pain (28% versus 21%) and disc herniation (37% versus 21%), as opposed to spinal stenosis (6% versus 15%), and spondylolisthesis (25% versus 41%). A higher percentage of patients in California received circumferential procedures (26% versus 5%), fusion of three or more levels (10% versus 5%), and bone morphogenetic protein (50% versus 31%). California had higher adjusted risk for reoperation (relative risk [RR] 2.28; 95% confidence interval [CI], 2.27-2.29), wound problems (RR 2.64; 95% CI, 2.62-2.65), device complications (RR 2.49; 95% CI, 2.38-2.61), and life-threatening complications (RR 1.31; 95% CI, 1.31-1.31). Hospital costs for the index procedure were greater in California ($49,430) than in Washington ($40,114). Broader lumbar fusion coverage policy was associated with greater use of lumbar fusion, use of more invasive operations, more reoperations, higher rates of complications, and greater inpatient costs.
    The spine journal: official journal of the North American Spine Society 11/2013; · 2.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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.
    The spine journal: official journal of the North American Spine Society 07/2013; · 2.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Study Design. Retrospective cohort analysis of Medicare claims for 2006-2009.Objective. To examine whether interspinous distraction procedures are used selectively in patients with more advanced age or comorbidity; and whether they are associated with fewer complications, lower costs, and less revision surgery than laminectomy or fusion surgery.Summary of Background Data. A manufacturer-sponsored randomized trial suggested an advantage of interspinous spacer surgery over non-surgical care, but there are few comparisons with other surgical procedures. Furthermore, there are few population-based data evaluating patterns of use of these devices.Methods. We used Medicare inpatient claims data to compare age and comorbidity for patients with spinal stenosis having surgery (n = 99,084) with (1) an interspinous process spacer alone; (2) laminectomy and a spacer; (3) decompression alone; or (4) lumbar fusion (1-2 level). We also compared these four groups for cost of surgery and rates of revision surgery, major medical complications, wound complications, mortality, and 30-day readmission rates.Results. Patients who received spacers were older than those receiving decompression or fusion, but had little evidence of greater comorbidity. Patients receiving a spacer alone had fewer major medical complications than those undergoing decompression or fusion surgery (1.2% versus 1.8% and 3.3% respectively), but had higher rates of further inpatient lumbar surgery (16.7% versus 8.5% for decompression and 9.8% for fusion at 2 years). Hospital payments for spacer surgery were greater than for decompression alone, but less than for fusion procedures. These associations persisted in multivariate models adjusting for patient age, sex, comorbidity score, and previous hospitalization.Conclusion. Compared to decompression or fusion, interspinous distraction procedures pose a trade-off in outcomes: fewer complications for the index operation, but higher rates of revision surgery. This information should help patients make more informed choices, but further research is needed to define optimal indications for these new devices.
    Spine 01/2013; · 2.16 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Spine 10/2012; · 2.16 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Neurosurgery 08/2012; 71(2):E545. · 2.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: : Lumbar discectomy is the most commonly performed spine procedure. Academic spine centers with potentially differing caseloads and experience may have different outcomes. : To determine whether the choice of center in which surgery is performed affects lumbar discectomy outcomes. : Spine Patient Outcomes Research Trial participants with a confirmed diagnosis of intervertebral disc herniation undergoing standard first-time open discectomy were followed from baseline at 6 weeks, and 3, 6, and 12 months, and yearly thereafter, at 13 spine clinics in 11 US states. Patient data from this prospective study were reviewed. Enrollment began in March 2000 and ended in November 2004. : Seven hundred ninety-two patients underwent first-time lumbar discectomy. Significant differences were found among centers in patient age and race, baseline levels of disability, and treatment preferences. There were no significant differences among the centers in other patient characteristics (eg, sex, body mass index, the prevalence of smoking, diabetes, or hypertension), or disease characteristics (herniation level or type). Some short-term outcomes varied significantly among centers, including operative duration and blood loss, the incidence of durotomy, the length of hospital stay, and reoperation rate. However, there were no differences among the centers in incidence of nerve root injury, postoperative mortality, Short Form 36 scores of body pain or physical function, or Oswestry Disability Index at 4 years. : Although mean blood loss, risk of durotomy, length of stay, and rate of reoperation vary among academic spine centers performing lumbar discectomy, there appears to be no difference in long-term functional outcomes. : AUC, area under the curveIDH, intervertebral disc herniationSBI, Sciatica Bothersomeness IndexSF-36, Short Form 36SPORT, Spine Patient Outcomes Research Trial.
    Neurosurgery 07/2012; 71(4):833-43. · 2.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: To identify factors that account for variation in complication rates across hospitals and surgeons performing lumbar spinal fusion surgery. DATA SOURCES: Discharge registry including all nonfederal hospitals in Washington State from 2004 to 2007. STUDY DESIGN: We identified adults (n = 6,091) undergoing an initial inpatient lumbar fusion for degenerative conditions. We identified whether each patient had a subsequent complication within 90 days. Logistic regression models with hospital and surgeon random effects were used to examine complications, controlling for patient characteristics and comorbidity. PRINCIPAL FINDINGS: Complications within 90 days of a fusion occurred in 4.8 percent of patients, and 2.2 percent had a reoperation. Hospital effects accounted for 8.8 percent of the total variability, and surgeon effects account for 14.4 percent. Surgeon factors account for 54.5 percent of the variation in hospital reoperation rates, and 47.2 percent of the variation in hospital complication rates. The discretionary use of operative features, such as the inclusion of bone morphogenetic proteins, accounted for 30 and 50 percent of the variation in surgeons' reoperation and complication rates, respectively. CONCLUSIONS: To improve the safety of lumbar spinal fusion surgery, quality improvement efforts that focus on surgeons' discretionary use of operative techniques may be more effective than those that target hospitals.
    Health Services Research 06/2012; · 2.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The treatment of craniocervical instability in children is often challenging due to their small spine bones, complex anatomy, and unique syndromes. The authors discuss their surgical experience with 33 cases in the treatment of 31 children (≤ 17 years of age) with craniocervical spine instability using smaller nontraditional titanium screws and plates, as well as intraoperative CT. All craniocervical fusion procedures were performed using intraoperative fluoroscopic imaging and electrophysiological monitoring. Nontraditional spine hardware included smaller screw sizes (2.4 and 2.7 mm) from the orthopedic hand/foot set and mandibular plates. Twenty-three of the 33 surgical procedures were performed with intraoperative CT, which was used to confirm adequate position of the spine hardware and alignment of the spine. The mean patient age was 9.5 years (range 2-17 years). Eleven children underwent a posterior C1-2 transarticular screw fusion, 17 had an occipitocervical fusion, and 3 had a posterior subaxial cervical fusion. The follow-up duration ranged from 9 to 72 months (mean 53 months). All children demonstrated successful fusion at their 3-month follow-up visit, except 1 patient whose unilateral C1-2 transarticular screw fusion required a repeat surgery before proper fusion was achieved. Of the 47 C1-2 transarticular screws that were placed, 13 were 2.4 mm, 15 were 2.7 mm, 7 were 3.5 mm, and 12 were 4.0 mm. Eighteen of the 47 C1-2 transarticular screws were suboptimally placed. Eleven of these misplaced screws were removed and redirected within the same operation because these surgeries benefitted from the use of intraoperative CT; 6 of the 7 remaining suboptimally placed screws were left in place because a second surgery for screw replacement was not warranted. The other suboptimally placed C1-2 screw was replaced during a repeat operation due to failure of fusion. Use of intraoperative CT was invaluable because it enabled the authors to reposition suboptimal C1-2 transarticular screws without necessitating a second operation. Successful craniocervical fusion procedures were achieved using smaller nontraditional titanium screws and plates. Intraoperative CT was a helpful adjunct for confirming and readjusting the trajectory of the screws prior to leaving the operating room, which decreases overall treatment costs and reduces complications.
    Journal of Neurosurgery Pediatrics 06/2012; 9(6):594-601. · 1.63 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Retrospective review of a prospectively collected multi-institutional database. In the present analysis, we investigate the impact of incidental durotomy on outcome in patients undergoing surgery for lumbar degenerative spondylolisthesis. Surgery for lumbar degenerative spondylolisthesis has several potential complications, one of the most common of which is incidental durotomy. The effect of incidental durotomy on outcome, however, remains uncertain. Spine Patient Outcomes Research Trial cohort participants with a confirmed diagnosis of lumbar degenerative spondylolisthesis undergoing standard first-time open decompressive laminectomy, with or without fusion, were followed from baseline at 6 weeks, at 3, 6, 12 months, and yearly thereafter, at 13 spine clinics in 11 US states. Patient data from this prospectively gathered database were reviewed. As of May 2009, the mean (standard deviation [SD]) follow-up among all analyzed degenerative spondylolisthesis patients was 46.6 months (SD = 13.1) (no durotomy: 46.7 vs. had durotomy: 45.2, P = 0.49). The median (range) follow-up time among all analyzed degenerative spondylolisthesis patients was 47.6 months (SD = 2.5-84). A 10.5% incidence of durotomy was detected among the 389 patients undergoing surgery. No significant differences were observed with or without durotomy in age, race, the prevalence of smoking, diabetes and hypertension, decompression level, number of levels, or whether a fusion was performed. There were no differences in incidence of nerve root injury, postoperative mortality, additional surgeries, 36-Item Short Form Health Survey (SF-36) scores of body pain or physical function, or Oswestry Disability Index at 1, 2, 3, and 4 years. Incidental durotomy during first-time surgery for lumbar degenerative spondylolisthesis does not appear to impact outcome in affected patients.
    Spine 03/2012; 37(5):406-13. · 2.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Surgical site infection after spine surgery is a well-known complication that can result in poor outcomes, arthrodesis-site nonunion, and neurological injury. We hypothesized that a higher surgical invasiveness score will increase the risk for surgical site infection following spine surgery. Data were examined from patients undergoing any type of spinal surgery from January 1, 2003, to December 31, 2004, at two academic hospitals. The surgical invasiveness index is a previously validated instrument that accounts for the number of vertebral levels decompressed, arthrodesed, or instrumented as well as the surgical approach. Relative risks and 95% confidence intervals were calculated for each of the categorical variables. Multivariate binomial stepwise logistic regression was used to examine the association between surgical invasiveness and surgical site infection requiring a return to the operating room for treatment, adjusting for confounding risk factors. The regression analysis of 1532 patients who were evaluated for surgical site infection identified the following significant risk factors for surgical site infection: a body mass index of >35 (relative risk, 2.24 [95% confidence interval, 1.21 to 3.86]; p = 0.01), hypertension (relative risk, 1.73 [95% confidence interval, 1.05 to 2.85]; p = 0.03), thoracic surgery versus cervical surgery (relative risk, 2.57 [95% confidence interval, 1.20 to 5.60]; p = 0.01), lumbosacral surgery versus cervical surgery (relative risk, 2.03 [95% confidence interval, 1.10 to 4.05]; p = 0.02), and a surgical invasiveness index of >21 (relative risk, 3.15 [95% confidence interval, 1.37 to 6.99]; p = 0.01). Patients undergoing more invasive spine surgery as measured with the surgical invasiveness index had greater risk for having a surgical site infection that required a return to the operating room for treatment. Surgical invasiveness was the strongest risk factor for surgical site infection, even after adjusting for medical comorbidities, age, and other known risk factors. The magnitude of this association should be considered during surgical decision-making and intraoperative and postoperative care of the patient. These findings further validate the importance of the invasiveness index when performing safety and clinical outcome comparisons for spine surgery.
    The Journal of Bone and Joint Surgery 02/2012; 94(4):335-42. · 3.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Repeat lumbar spine surgery is generally an undesirable outcome. Variation in repeat surgery rates may be because of patient characteristics, disease severity, or hospital- and surgeon-related factors. However, little is known about population-level variation in reoperation rates. To examine hospital- and surgeon-level variation in reoperation rates after lumbar herniated disc surgery and to relate these to published benchmarks. Retrospective analysis of a discharge registry including all nonfederal hospitals in Washington State. We identified adults who underwent an initial inpatient lumbar decompression for herniated disc from 1997 to 2007. We then performed generalized linear mixed-effect logistic regressions, controlling for patient characteristics and comorbidity, to examine the variation in reoperation rates within 90 days, 1 year, and 4 years. Our cohort included 29,529 patients with a mean age of 47.5 years, 61% privately insured, and 15% having any comorbidity. The age-, sex-, insurance-, and comorbidity-adjusted mean rate of reoperation among hospitals was 1.9% at 90 days (95% confidence interval [CI], 1.2-3.1), with a range from 1.1% to 3.4%; 6.4% at 1 year (95% CI, 3.9-10.6), with a range from 2.8% to 12.5%; and 13.8% at 4 years (95% CI, 8.8-19.8), with a range from 8.1% to 24.5%. The adjusted mean reoperation rates of surgeons were 1.9% at 90 days (95% CI, 1.4-2.4) with a range from 1.2% to 4.6%, 6.1% at 1 year (95% CI, 4.8-7.7) with a range from 4.3% to 10.5%, and 13.2% at 4 years (95% CI, 11.3-15.5) with a range from 10.0% to 19.3%. Multilevel random-effect models suggested that variation across surgeons was greater than that of hospitals and that this effect increased with long-term outcomes. Even after adjusting for patient demographics and comorbidity, we observed a large variation in reoperation rates across hospitals and surgeons after lumbar discectomy, a relatively simple spinal procedure. These findings suggest uncertainty about indications for repeat surgery, variations in perioperative care, or variations in quality of care.
    The spine journal: official journal of the North American Spine Society 12/2011; 12(2):89-97. · 2.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: For carefully selected patients with lumbar stenosis, decompression surgery is more efficacious than nonoperative treatment. However, some patients undergo repeat surgery, often because of complications, the failure to achieve solid fusion following arthrodesis procedures, or persistent symptoms. We assessed the probability of repeat surgery following operations for the treatment of lumbar stenosis and examined its association with patient age, comorbidity, previous surgery, and the type of surgical procedure. We performed a retrospective cohort analysis of Medicare claims. The index operation was performed in 2004 (n = 31,543), with follow-up obtained through 2008. Operations were grouped by complexity as decompression alone, simple arthrodesis (one or two disc levels and a single surgical approach), or complex arthrodesis (more than two disc levels or combined anterior and posterior approach). Reoperation rates were calculated for each follow-up year, and the time to reoperation was analyzed with proportional hazards models. The probability of repeat surgery fell with increasing patient age or comorbidity. Aside from age, the strongest predictor was previous lumbar surgery: at four years the reoperation rate was 17.2% among patients who had had lumbar surgery prior to the index operation, compared with 10.6% among those with no prior surgery (p < 0.001). At one year, the reoperation rate for patients who had been managed with decompression alone was slightly higher than that for patients who had been managed with simple arthrodesis, but by four years the rates for these two groups were identical (10.7%) and were lower than the rate for patients who had been managed with complex arthrodesis (13.5%) (p < 0.001). This difference persisted after adjusting for demographic and clinical features (hazard ratio for complex arthrodesis versus decompression 1.56, 95% confidence interval, 1.26 to 1.92). A device-related complication was reported at the time of 29.2% of reoperations following an initial arthrodesis procedure. The likelihood of repeat surgery for spinal stenosis declined with increasing age and comorbidity, perhaps because of concern for greater risks. The strongest clinical predictor of repeat surgery was a lumbar spine operation prior to the index operation. Arthrodeses were not significantly associated with lower rates of repeat surgery after the first postoperative year, and patients who had had complex arthrodeses had the highest rate of reoperations.
    The Journal of Bone and Joint Surgery 11/2011; 93(21):1979-86. · 3.23 Impact Factor
  • Richard A Deyo, Sohail K Mirza, Brook I Martin
    JAMA The Journal of the American Medical Association 09/2011; 306(10):1088. · 29.98 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Combined prospective randomized controlled trial and observational cohort study of intervertebral disc herniation (IDH), an as-treated analysis. To determine modifiers of the treatment effect (TE) of surgery (the difference between surgical and nonoperative outcomes) for intervertebral disc herniation (IDH) using subgroup analysis. The Spine Patient Outcomes Research Trial demonstrated a positive surgical TE for IDH at the group level. However, individual characteristics may affect TE. No prior studies have evaluated TE modifiers in IDH. IDH patients underwent either discectomy (n = 788) or nonoperative care (n = 404) and were analyzed according to treatment received. Thirty-seven baseline variables were used to define subgroups for calculating the time-weighted average TE for the Oswestry Disability Index (ODI) across 4 years (TE = ΔODI(surgery) -ΔODI(nonoperative)). Variables with significant subgroup-by-treatment interactions (P < 0.1) were simultaneously entered into a multivariate model to select independent TE predictors. All analyzed subgroups improved significantly more with surgery than with nonoperative treatment (P < 0.05). In minimally adjusted univariate analyses, being married, absence of joint problems, worsening symptom trend at baseline, high school education or less, older age, no worker's compensation, longer duration of symptoms, and an SF-36 mental component score (MCS) less than 35 were associated with greater TEs. Multivariate analysis demonstrated that being married (TE, -15.8 vs. -7.7 single, P < 0.001), absence of joint problems (TE, -14.6 vs. -10.3 joint problems, P = 0.012), and worsening symptoms (TE, -15.9 vs. -11.8 stable symptoms, P = 0.032) were independent TE modifiers. TEs were greatest in married patients with worsening symptoms (-18.3) vs. single patients with stable symptoms (-7.8). IDH patients who met strict inclusion criteria improved more with surgery than with nonoperative treatment, regardless of specific characteristics. However, being married, without joint problems, and worsening symptom trend at baseline were associated with a greater TE.
    Spine 06/2011; 37(2):140-9. · 2.16 Impact Factor
  • Source
    Sohail K Mirza
    [Show abstract] [Hide abstract]
    ABSTRACT: COMMENTARY ON: Carragee EJ, Hurwitz EL, Weiner BK. A critical review of recombinant human bone morphogenetic protein-2 trials in spinal surgery: emerging safety concerns and lessons learned. Spine J 2011;11:471–91 (in this issue).
    The spine journal: official journal of the North American Spine Society 06/2011; 11(6):495-9. · 2.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Retrospective cohort study of Medicare claims. Examine trends and patterns in the use of bone morphogenetic proteins (BMP) in surgery for lumbar stenosis; compare complications, reoperation rates, and charges for patients undergoing lumbar fusion with and without BMP. Small, randomized trials have demonstrated higher rates of solid fusion with BMP than with allograft bone alone, with few complications and, in some studies, reduced rates of revision surgery. However, complication and reoperation rates from large population-based cohorts in routine care are unavailable. We identified patients with a primary diagnosis of lumbar stenosis who had fusion surgery in 2003 or 2004 (n = 16,822). We identified factors associated with BMP use: major medical complications during the index hospitalization, rates of rehospitalization within 30 days, and rates of reoperation within 4 years of follow-up (through 2008). Use of BMP increased rapidly, from 5.5% of fusion cases in 2003 to 28.1% of fusion cases in 2008. BMP use was greater among patients with previous surgery and among those having complex fusion procedures (combined anterior and posterior approach, or greater than 2 disc levels). Major medical complications, wound complications, and 30-day rehospitalization rates were nearly identical with or without BMP. Reoperation rates were also very similar, even after stratifying by previous surgery or surgical complexity, and after adjusting for demographic and clinical features. On average, adjusted hospital charges for operations involving BMP were about $15,000 more than hospital charges for fusions without BMP, though reimbursement under Medicare's Diagnosis-Related Group system averaged only about $850 more. Significantly fewer patients receiving BMP were discharged to a skilled nursing facility (15.9% vs. 19.0%, P < 0.001). In this older population having fusion surgery for lumbar stenosis, uptake of BMP was rapid, and greatest among patients with prior surgery or having complex fusion procedures. BMP appeared safe in the perioperative period, with no increase in major medical complications. Use of BMP was associated with greater hospital charges but fewer nursing home discharges, and was not associated with reduced likelihood of reoperation.
    Spine 04/2011; 37(3):222-30. · 2.16 Impact Factor

Publication Stats

3k Citations
323.93 Total Impact Points

Institutions

  • 2013
    • Dartmouth College
      • Dartmouth Institute for Health Policy and Clinical Practice
      Hanover, New Hampshire, United States
  • 2009–2013
    • Geisel School of Medicine at Dartmouth
      • Department of Orthopaedics
      Hanover, New Hampshire, United States
  • 2011–2012
    • Dartmouth–Hitchcock Medical Center
      • Department of Surgery
      Lebanon, New Hampshire, United States
  • 1997–2012
    • University of Washington Seattle
      • • Department of Orthopaedics and Sports Medicine
      • • Department of Medicine
      • • Department of Mechanical Engineering
      Seattle, WA, United States
  • 2009–2011
    • Oregon Health and Science University
      • Department of Family Medicine
      Portland, OR, United States
  • 2008
    • Trinity Washington University
      Washington, Washington, D.C., United States
  • 2007
    • University of California, Davis
      • Department of Family and Community Medicine
      Davis, CA, United States
  • 2006
    • United States Army
      Washington, West Virginia, United States
  • 2002
    • University of Vienna
      Wien, Vienna, Austria
    • University of Louisville
      • Department of Radiology
      Louisville, KY, United States
  • 1999
    • University of Toronto
      Toronto, Ontario, Canada