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Study Design: Multicenter retrospective cohort study.Objective: The aim of this study was to compare reoperation rates at 5-year follow-up of unilateral laminotomy for bilateral decompression (ULBD) versus posterior decompression with instrumented fusion (Fusion) for patients with low-grade degenerative spondylolisthesis (DS) with lumbar spinal stenosis (LSS) in a multicenter database.Summary Of Background Data: Controversy exists regarding whether fusion should be used to augment decompression surgery in patients with LSS with DS. For years, the standard has been fusion with standard laminectomy to prevent postoperative instability. However, this strategy is not supported by Level 1 evidence. Instability and reoperations may be reduced or prevented using less invasive decompression techniques.Methods: We identified 164 patients with DS and LSS who underwent ULBD between January 2007 and December 2011 in a multicenter database. These patients were propensity score-matched on age, sex, race, and smoking status with patients who underwent Fusion (n = 437). Each patient required a minimum of 5-year follow-up. The primary outcome was 5-year reoperation. Secondary outcome measures included postoperative complication rates, blood loss during surgery, and length of stay. Logistic regression models were used to estimate the odds ratio of the 5-year reoperation rate between the two surgical groups.Results: The reoperation rate at 5-year follow-up was 10.4% in the ULBD group and 17.2% in the Fusion group. ULBD reoperations were more frequent at the index surgical level; Fusion reoperations were more common at an adjacent level. The two types of operations had similar postoperative complication rates, and both groups tended to have fusion reoperations.Conclusion: For patients with stable DS and LSS, ULBD is a viable, durable option compared to fusion with decreased blood loss and length stay, as well as a lower reoperation rate at 5-year follow-up. Further prospective studies are required to determine the optimal clinical scenario for ULBD in the setting of DS.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective imaging review.Objective: Utilize magnetic resonance imaging (MRI) to expand the anatomical description of psoas morphology and its association with neurovascular structures at L4-5.Summary Of Background Data: Anatomical psoas muscle variants may present a greater risk of neurovascular injury at the L4-5 level during lateral transpsoas approaches.Methods: Axial L4-5 sections of consecutive patients who obtained lumbar MRIs were analyzed. Teardrop psoas morphology was assessed qualitatively. MRI described psoas morphology and proximity of neurovascular structures, whereas plain radiographs were evaluated for lumbosacral transitional vertebrae (LSTV). Teardrop morphology was tested for associations with radiographic measurements using t tests and χ analysis.Results: Fifty teardrop and 476 nonteardrop psoas muscles were identified. Teardrop morphology was associated with greater longitudinal length (53.1 vs. 49.3 mm, P = 0.012), and shorter transverse length (34.9 vs. 44.8 mm, P < 0.001) compared with nonteardrop. Teardrop morphology was associated with anterior and lateral migration of the psoas with greater distance between the anterior borders of the psoas and disc (13.5 vs. 6.3 mm, P < 0.001), and greater distance between the medial border of the psoas to the lateral disc border (1.6 vs. 0.5 mm, P < 0.001). Teardrop morphology was associated with a higher incidence of the lumbar plexus migrating anteriorly adjacent to the middle-third of the disc (43.4% vs. 17.6%, P < 0.001) and the iliac vasculature being more laterally and posteriorly located, adjacent to the anterior-third of the disc (43.4% vs. 30.0%, P = 0.047). Teardrop morphology was not associated with presence of LSTV (3.8% vs. 7.6%, P = 0.306).Conclusion: The current study provides detailed metrics of teardrop psoas muscles and surrounding structures. The study confirms that the presence of teardrop anatomy on L4-5 axial imaging is associated with anterior migration of the lumbar plexus and posterolateral migration of the iliac vasculature which may increase the risk of neurovascular injury during direct and oblique-lateral lumbar spine procedures.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Background Context: Although lumbar spinal stenosis often presents as a degenerative condition (degenerative stenosis [DS]), some patients present with symptoms from lifelong narrowing of the spinal canal. These patients have congenital stenosis (CS) and present with symptoms of stenosis at a younger age. Patients with CS often have a distinct pathophysiology with fewer degenerative changes but present with multilevel involvement. In the setting of neurologic symptoms, decompression alone while preserving stability has been proposed for both patient populations.Purpose: The purpose of this study is to evaluate if the different etiology for narrowing in CS and DS results in a different natural history of pain progression, different locations requiring decompression, and different outcomes following a stability-preserving decompression procedure.Study Design/setting: This study used a retrospective cohort study patient sample: We retrospectively reviewed consecutive patients of a single surgeon with DS or CS who underwent surgical decompression without fusion between 2008 and 2014. Patients were excluded if they had undergone a previous lumbar surgical procedure (decompression or fusion) or follow-up less than 12 months.Outcome Measures: Pre- and postoperative clinical outcome scores including visual analogue scale (VAS) and Oswestry Disability Index (ODI) were recorded. Postoperatively, data were collected regarding complications, the presence of new radicular or myelopathic symptoms, and necessity of reoperation in the lumbar spine.Methods: Demographic information included age, sex, body mass index, smoking status, and Charleston Comorbidity Index (CCI). Preoperative clinical symptoms as well as the presence of lower extremity radiculopathy and claudication were evaluated. Patients were determined to have a diagnosis of CS by the treating surgeon if primary radiographs revealed shortened pedicles and decreased cross-sectional area of the spinal canal as detailed by previous studies. Binary outcomes were compared between congenital and degenerative cohorts using bivariate and multivariate logistic regression. Multivariate regressions controlled for baseline patient and operative characteristics.Results: The average age of the DS cohort was 66.7±10.7 years, whereas for the CS group, it was 47.1±9.2 years. Average follow-up was 27.6 months. The patients with DS had significantly more comorbidities as shown by the CCI score (2.8±1.6 vs. 0.5±0.6); p<.001) and the American Society of Anesthesiologists (ASA) score ≥3 (52.8% vs. 11.1%; p<.001). Patients with CS presented with higher VAS back (8.0 vs. 5.1; p=.008) and leg (7.9 vs. 4.5; p<.001) scores. Patients with DS presented with significantly greater duration of preoperative back pain and leg pain (42.7 vs. 30.5 months; p=.042). Postoperatively, there were no significant differences in VAS back, leg, or ODI scores. However, a trend toward a lower VAS leg score was present in the patients with CS when compared with patients with DS (2.6±3.0 vs. 4.2±3.2; p<.117). Both patient groups experienced similar levels of symptomatic relief and improvement in VAS and ODI scores. There were no significant differences in new-onset radicular symptoms requiring conservative treatment or reoperation. In both groups combined, 81.9% of patients reported resolution of lower extremity symptoms at final follow-up. Overall, 20.6% of patients experienced new lower-extremity radicular symptoms after a period of resolution of symptoms postoperatively. There were significantly more reoperations following surgical decompression in patients with DS (13.9% vs. 2.8%; p=.02).Conclusions: Patients with CS and patients with DS respond well to decompression alone, without a supplemental fusion, despite differences in pain experience and presentation. The localization of pathology requiring decompression is similar. The patients with DS were more susceptible to require another operation resulting in a fusion, which confirms the theory that initial microinstability can progress in DS, but is likely not part of the disease process in CS. At just over 2 years after decompression, patients with CS may not need to be treated by a fusion in the setting of lower back pain; however, longer-term follow up is necessary to further assess these outcomes. [ABSTRACT FROM AUTHOR]

Background context The Spine Patient Outcomes Research Trial (SPORT) is a highly referenced clinical trial that randomized patients with lumbar pathology to receive surgery or continued conservative treatment. Purpose The purpose of this study was to compare the SPORT lumbar disc herniation cohort and an analogous cohort from the National Surgical Quality Improvement Program (NSQIP) database. Study design/setting This is a retrospective cohort study comparing a national database population to a randomized clinical trial. Patient sample Elective lumbar discectomies from NSQIP between 2010 and 2012 were used. Outcome measures Demographics were compared between the randomized SPORT cohorts (surgical and nonoperative) and NSQIP. Perioperative factors and complications were then compared between SPORT discectomy patients and NSQIP. Methods Using current procedural terminology and International Classification of Diseases , ninth revision codes, all elective lumbar discectomies from NSQIP between 2010 and 2012 were identified. Where possible based on the published data and variables available in each cohort, the two populations were compared. Results A total of 6,846 NSQIP discectomy patients were compared with the randomized SPORT surgical and nonoperative cohorts. Demographic comparisons showed that NSQIP patients were older (average age 48.2±14.5 years [mean±standard deviation] vs. 41.7±11.8 and 43.0±11.3 years, respectively [p<.001]) and had higher body mass index (29.6±6.2 kg/m 2 vs. 27.8±5.6 and 28.2±5.4 kg/m 2 , respectively [p<.001]). No statistical differences existed for gender or race. Smoking status was not different between the SPORT nonoperative group and NSQIP but was higher in NSQIP compared with SPORT surgical patients (p=.020 by 7%). Comparisons of perioperative factors and complications between the SPORT surgical cohort and NSQIP showed no statistical difference in average operative time, length of stay, deep wound infections, wound dehiscence, total wound complications, or blood transfusions. Spine Patient Outcomes Research Trial superficial wound infection rates were higher than NSQIP (p=.029 by 1.4%). As expected, SPORT 1-year reoperation rates were higher than NSQIP 30-day rates (7% vs. 2%, p<.001). Conclusions Spine Patient Outcomes Research Trial lumbar disc herniation results are similar to those from a large national patient sample. Even statistically significant differences would be considered clinically similar. These findings support the generalizability of the SPORT lumbar disc herniation results. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective cohort. Objective. To compare demographics and perioperative outcomes between the Spine Patient Outcomes Research Trial (SPORT) lumbar degenerative spondylolisthesis arm and a similar population from the National Surgical Quality Improvement Program (NSQIP) database. Summary of Background Data. SPORT is a well-known surgical trial that investigated the benefits of surgical versus nonsurgical treatment in patients with various lumbar pathologies. However, the external validity of SPORT demographics and outcomes has not been fully established. Methods. Surgical degenerative spondylolisthesis cases were identified from NSQIP between 2010 and 2012. This population was then compared with the SPORT degenerative spondylolisthesis study. These comparisons were based on published data from SPORT and included analyses of demographics, perioperative factors, and complications. Results. The 368 surgical patients with degenerative spondylolisthesis in SPORT were compared with 955 patients identified in NSQIP. Demographic comparisons were as follows: average age and race (no difference; P > 0.05 for each), sex (9.1% more female patients in SPORT; P = 0.002), smoking status (6.6% more smokers in NSQIP; P = 0.002), and average body mass index (1.1 kg/m 2 greater in NSQIP; P = 0.005). Larger differences were noted in what surgical procedure was performed ( P < 0.001), with the most notable difference being that the NSQIP population was much more likely to include interbody fusion than the SPORT population (52.4% vs. 12.5%). Most perioperative factors and complication rates were similar, including average operative time, wound infection, wound dehiscence, postoperative transfusion, and postoperative mortality (no differences; P > 0.05 for each). Average length of stay was shorter in NSQIP compared with SPORT (3.7 vs. 5.8 d; P = 0.042). Conclusion. Though important differences in the distribution of surgical procedures were identified, this study supports the greater generalizability of the surgical SPORT degenerative spondylolisthesis study based on similar demographics and perioperative outcomes when compared with patients from the NSQIP database. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective database review. Objective. To evaluate whether microscope use during spine procedures is associated with increased operating room times or increased risk of infection. Summary of Background Data. Operating microscopes are commonly used in spine procedures. It is debated whether the use of an operating microscope increases operating room time or confers increased risk of infection. Methods. The American College of Surgeons National Surgical Quality Improvement Program database, which includes data from more than 370 participating hospitals, was used to identify patients undergoing elective spinal procedures with and without the use of an operating microscope for the years 2011 and 2012. Bivariate and multivariate linear regressions were used to test the association between microscope use and operating room times. Bivariate and multivariate logistic regressions were similarly conducted to test the association between microscope use and infection occurrence within 30 days of surgery. Results. A total of 23,670 elective spine procedures were identified, of which 2226 (9.4%) used an operating microscope. The average patient age was 55.1 ± 14.4 years. The average operative time (incision to closure) was 125.7 ± 82.0 minutes. Microscope use was associated with minor increases in preoperative room time (+2.9 min, P = 0.013), operative time (+13.2 min, P < 0.001), and total room time (+18.6 min, P < 0.001) on multivariate analysis. A total of 328 (1.4%) patients had an infection within 30 days of surgery. Multivariate analysis revealed no significant difference between the microscope and nonmicroscope groups for occurrence of any infection, superficial surgical site infection, deep surgical site infection, organ space infection, or sepsis/septic shock, regardless of surgery type. Conclusion. We did not find operating room times or infection risk to be significant deterrents for use of an operating microscope during spine surgery. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective cohort study. Objective. To identify factors that are independently associated with increased surgical drain output in patients who have undergone ACDF. Summary of Background Data. Surgical drains are typically placed after ACDF to reduce the risk of complications associated with neck hematoma. The orthopedic literature has repeatedly challenged the use of surgical drains after many procedures, and there are currently no guidelines for determining which patients are most likely to benefit from drain placement after ACDF. Methods. Consecutive patients who underwent elective ACDF with surgical drain placement at a single academic institution between January 2011 and February 2013 were identified using billing records. Patient information was abstracted from the medical record. Patients were categorized on the basis of normal or increased total drain output, with increased drain output defined as total drain output 50th percentile (30 mL) or more. A multivariate logistic regression was used to determine which factors were independently associated with increased drain output. Results. A total of 151 patients with ACDF met inclusion criteria. Total drain output was in the range from 0 mL to 265 mL. The average drain output for this cohort was 42.3 ± 45.5 mL (mean ± standard deviation). Among all patients in the study, 80 patients had increased drain output (drain output ≥50th percentile or 30 mL). Multivariate analysis identified 3 independent predictors of increased drain output: age 50 years or more (odds ratio [OR] = 3.9), number of levels (2 levels, OR = 2.7; 3-4 levels, OR = 17.0), and history of smoking (OR = 2.8). One patient developed a postoperative neck hematoma while a drain was in place. Conclusion. Patients with the factors associated with increased drain output identified in the earlier text may benefit most from surgical drain placement after ACDF. Nonetheless, neck hematoma is still possible even with drain use. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Controversy exists regarding whether fusion should be used to augment decompression surgery in patients with symptomatic lumbar spinal stenosis with grade I/II (low-grade), stable degenerative spondylolisthesis. For years, the standard has been fusion with laminectomy in order to prevent postoperative instability. However, instability and reoperations may be reduced or prevented using less invasive, structure sparing decompression techniques without the need for fusion. PURPOSE To compare reoperation rates within a 5-year follow-up period of unilateral laminotomy for bilateral decompression (ULBD) versus posterior lumbar decompression with instrumented fusion (fusion) for patients with degenerative spondylolisthesis with spinal stenosis in a multicenter database. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE A final cohort of 601 Kaiser Permanente Northern California members with diagnoses of lumbar degenerative spondylolisthesis and lumbar spinal stenosis of whom 164 patients underwent ULBD and 437 underwent fusion between January 2007 and December 2011. OUTCOME MEASURES The primary outcome measure was reoperation rate at 5-year postoperative follow-up. Secondary outcome measures included blood loss during surgery, length of stay, reoperation type, reoperation level, and 90-day postoperative complication rates. METHODS We identified 164 patients with lumbar degenerative spondylolisthesis and lumbar stenosis who underwent ULBD between January 2007 and December 2011. These patients were propensity score matched on age at surgery, gender, race and smoking status with patients who underwent fusion (n=437). The primary outcome was 5-year reoperation rate and secondary outcome measures included postoperative complication rates, reoperation type, reoperation level, blood loss during surgery, and length of stay. RESULTS The reoperation rate within 5-year follow-up was significantly lower at 10.4% in the ULBD group compared to 17.2% in the fusion group (p=.0393). Type of reoperation was similar between the two groups. Reoperation at the index or adjacent level was not significant different between the two groups. Patients that underwent ULBD had significantly less mean estimated blood loss compared to fusion (82 vs. 445 ml, p<.0001) and significantly shorter mean length of stay (2.3 vs. 4.6 days, p<.0001). The two types of operations had similar postoperative complication rates, with less surgical site infections for ULBD compared with fusion (1 vs. 11 cases). There was no difference in the Charlson Comorbidity Index between the two groups. CONCLUSIONS For patients with stable degenerative spondylolisthesis and lumbar stenosis, ULBD is a viable, durable option compared to fusion with a lower reoperation rate within a 5-year follow-up period, as well as decreased blood loss and length of stay. Further prospective studies are required to determine the optimal clinical scenario for ULBD in the setting of degenerative spondylolisthesis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs [ABSTRACT FROM AUTHOR]