Faculty Bibliography

Hypothesis: A single T1 Spino Pelvic Angle (TPA) can be associated with drastically different HRQOL but it can easily be supplemented to convey both global alignment and meaningful clinical outcome. Design: Retrospective cohort. Introduction: TPA is a valuable perioperative planning tool that accounts for both pelvic tilt (PT) and trunk inclination. However, it is limited as a standalone parameter because it does not distinguish patients' ability to compensate with pelvic retroversion. For a given TPA, patients who are unable to recruit compensatory mechanisms may have significantly worse HRQOL scores than those who can. Can TPA be augmented to better describe a patient's global alignment and more accurately predict HRQOL? Methods: Single-center study of patients with full body X-ray, HRQOL and TPA >10degree. Proportions of PT to TPA (PTp = PT/TPA) and T1SPi to TPA (T1SPip = T1SPi/TPA) were calculated and investigated against increased values of TPA. Then, 2 sub-groups were created (HighPT and LowPT) based on mean (PTp) +/- 0.5 standard deviation. HighPT and LowPT were compared across the entire cohort using an unpaired T-test. Results: 230 patients were included (58.7 +/- 15.5 y, 60 %F). Mean sagittal parameters included: PI-LL 12.3 +/- 16.3degree, SVA 41 +/- 49 mm, TPA 21.9 +/- 10.1degree and PT 24.4 +/- 8.6degree. The analysis of PTp distribution revealed a decrease in PT recruitment as TPA increases (137 +/- 39 % for patients with TPA <15degree, 87 +/- 15 % for patients with TPA>40degree). Comparing LowPT (n = 57) with HighPT (n = 69) revealed that for a similar TPA (24.1 vs. 22.1degree, p = 0.308), patients with LowPT (and therefore little compensatory PT) had significantly worse HRQL scores in terms of ODI (45 vs. 32 in HighPT; p = 0.002) and EQ-5D (9.7 vs. 8.5 in HighPT, p = 0.003). Conclusions: While TPA captures the severity of deformity, disability is a product of deformity severity and the inability to recruit compensatory mechanisms. TPA measures the severity of the thoracolumbar deformity separate from pelvic compensation. Therefore for a complete picture of standing sagittal alignment, TPA should be considered in conjunction with PT to convey the full radiological and clinical picture. Failing to do so potentially masks a patient's disability

STUDY DESIGN: Retrospective analysis of relevant in-hospital patient records from the New York State Inpatient Database. OBJECTIVE: We aimed to assess reoperation risk in adolescent idiopathic scoliosis (AIS) by surgeon and hospital operative volume. SUMMARY OF BACKGROUND DATA: The need for early reoperation can be devastating for patient and family, is a burden to the physician and adds significant cost. Previous studies have shown improved outcomes associated with higher volume surgeons and hospitals, but reoperation events have not yet been explored. METHODS: The 2008-2011 New York State Inpatient Database was queried using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for adolescent idiopathic scoliosis patients aged 10-21 undergoing spine arthrodesis. Patient identifiers and revisit linkage variables were used to identify reoperation events. Annual surgeon and hospital volumes were stratified into tertiles (low, medium, high) via identifier codes. The relative risk of reoperation after spine arthrodesis was computed based on relevant patient inpatient stays. RESULTS: Over 2008 to 2011, a total of 3,928 primary fusion operations for AIS were identified. The overall rate of reoperation after spine fusion for idiopathic scoliosis was 7.1%. Low volume surgeons performed less than 6 AIS fusions per year, medium volume surgeons performed less than 43, and high volume surgeons performed from 43 to 228. Reoperation after a primary fusion for adolescent idiopathic scoliosis showed reduced frequency among higher volume surgeons (14.1% for low vs. 5.1% for high, p<0.001, see Table for Hospitals). CONCLUSIONS: Early reoperation after spine fusion for idiopathic scoliosis is seen more frequently in lower volume institutions and surgeons. Appreciating the resources and limitations at a clinician's institution is important to developing practices to prevent these devastating events. This work also has implications for strategies that aim to direct limited healthcare resources to centers with low complication rates.

BACKGROUND: Lumbar discectomy and laminectomy in patients with intervertebral disc herniation (IDH) is common, with variable reported reoperation rates. Our study examined which baseline characteristics might be risk factors for reoperation and compared outcomes between patients who underwent reoperation and those who did not. METHODS: We performed a retrospective subgroup analysis of patients from the IDH arm of the Spine Patient Outcomes Research Trial (SPORT) randomized and observational cohorts. We analyzed baseline characteristics and outcomes of patients who underwent reoperation and those who did not with use of data collected from enrollment through eight-years of follow-up after surgery. Follow-up times were measured from the time of surgery, and baseline covariates were updated to the follow-up immediately preceding the time of surgery for outcomes analyses. RESULTS: At eight years, the reoperation rate was 15% (691 no reoperation; 119 reoperation). Sixty-two percent of these patients underwent reoperation because of a recurrent disc herniation; 25%, because of a complication or other factor; and 11%, because of a new condition. The proportion of reoperations that were performed for a recurrent disc herniation ranged from 58% to 62% in the individual years. Older patients were less likely to have reoperation (p = 0.015), as were patients presenting with asymmetric motor weakness at baseline (p = 0.0003). Smoking, diabetes, obesity, Workers' Compensation, and clinical depression were not associated with a greater risk of reoperation. Scores on the Short Form (SF)-36 for bodily pain and physical functioning, the Oswestry Disability Index (ODI), and the Sciatica Bothersomeness Index as well as satisfaction with symptoms had improved less at the time of follow-up in the reoperation group (p < 0.001). CONCLUSIONS: In patients who underwent surgery for IDH, the overall reoperation rate was 15% at the eight-year follow-up. Patients of older age and patients presenting with asymmetric motor weakness were less likely to undergo a reoperation. Less improvement in patient-reported outcomes was noted in the reoperation group. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

STUDY DESIGN: Analysis of the Nationwide Inpatient Sample database. OBJECTIVE: To investigate national trends, risks, and benefits of surgical interventions for degenerative spondylolisthesis (DS). SUMMARY OF BACKGROUND DATA: The surgical management of DS continues to evolve whereas the most clinically and cost-effective treatment is debated. With an aging US population and growing restraints on a financially burdened health care system, a clear understanding of national trends in the surgical management of DS is needed. METHODS: The Nationwide Inpatient Sample database was queried for patients with DS undergoing lumbar fusions from 2001 to 2010, using International Classification of Diseases, Ninth Revision (ICD-9) diagnosis and procedure codes. Analyses compared instrumented posterolateral fusion (PLF), posterolateral fusion with anterior lumbar interbody fusion (ALIF + PLF), PLF with posterior interbody fusion (P/TLIF + PLF), anterior instrumented interbody fusion (ALIF), and posterior interbody fusion with posterior instrumentation (P/TLIF). Clinical data were analyzed representing the initial acute phase care after surgery. RESULTS: There were 48,911 DS surgical procedures identified, representing 237,383 procedures. The percentage of patients undergoing PLF, ALIF + PLF, or ALIF increased whereas the percentage of P/TLIF or P/TLIF + PLF decreased over time. Total charges were less (P < 0.001), average length of hospital stay was shorter (P < 0.01), and average age was older (P < 0.01) for patients who underwent PLF compared with any other procedure. Type of procedure varied on the basis of the geographic region of the hospital, teaching versus nonteaching hospital, and size of hospital (P < 0.01). Patients who had P/TLIF + PLF or ALIF had a higher risk of mortality than patients who had PLF (odds ratios: 5.02, 2.22, respectively). Patients were more likely to develop a complication if they had ALIF + PLF, P/TLIF + PLF, ALIF, and P/TLIF than if they had PLF (odds ratios: 1.45, 1.23, 1.49, 1.12, respectively). CONCLUSION: Variation in the surgical management of DS related to patient demographics, hospital charges, length of hospital stay, insurance type, comorbidities, and complication rates was found within the Nationwide Inpatient Sample database. During the acute phase of care immediately after surgery, PLF procedures were found to reduce length of hospital stay, hospital charges, and postoperative complications. LEVEL OF EVIDENCE: 3.

The demand for spinal surgery and its costs have both risen over the past decade. In 2008 the aggregate hospital bill for surgical care of all spinal procedures was reported to be $33.9 billion. One key driver of rising costs is spinal implants. In 2011 our institution implemented a cost containment programme for spinal implants which was designed to reduce the prices of individual spinal implants and to reduce the inter-surgeon variation in implant costs. Between February 2012 and January 2013, our spinal surgeons performed 1493 spinal procedures using implants from eight different vendors. By applying market analysis and implant cost data from the previous year, we established references prices for each individual type of spinal implant, regardless of vendor, who were required to meet these unit prices. We found that despite the complexity of spinal surgery and the initial reluctance of vendors to reduce prices, significant savings were made to the medical centre. Cite this article: 2015; 97-B:1102-5.

BACKGROUND: Wound drains that are left in place for a prolonged period of time have a higher rate of bacterial contamination. Following spinal surgery, a drain is often left in place for a longer period of time if it maintains a high output. Given the major consequences of an infection following spinal surgery and the lack of data with regard to the use of antibiotics and drains, we performed a study of patients with a drain following spinal surgery to compare infection rates between those who were treated with antibiotics for twenty-four hours and those who received antibiotics for the duration for which the drain was in place. METHODS: We performed a prospective randomized trial of 314 patients who underwent multilevel thoracolumbar spinal surgery followed by use of a postoperative drain. The patients were randomized into two groups, one of which received perioperative antibiotics for twenty-four hours (twenty-four-hour group) and the other of which received antibiotics for the duration that the drain was in place (drain-duration group). Data collected included demographic characteristics, medical comorbidities, type of spinal surgery, and surgical site infection. RESULTS: Twenty-one (12.4%) of the 170 patients in the twenty-four-hour group and nineteen (13.2%) of the 144 in the drain-duration group developed a surgical site infection (p = 0.48). There were no significant differences between the twenty-four-hour and drain-duration groups with respect to demographic characteristics (except for the American Society of Anesthesiologists [ASA] classification), operative time, type of surgery, drain output, or length of hospital stay. CONCLUSIONS: Continuing perioperative administration of antibiotics for the entire duration that a drain is in place after spinal surgery did not decrease the rate of surgical site infections. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Myocardial necrosis in the perioperative period of noncardiac surgery is associated with short-term mortality, but long-term outcomes have not been characterized. We investigated the association between perioperative troponin elevation and long-term mortality in a retrospective study of consecutive subjects who underwent hip, knee, and spine surgery. Perioperative myocardial necrosis and International Classification of Disease, Ninth Revision-coded myocardial infarction (MI) were recorded. Long-term survival was assessed using the Social Security Death Index database. Logistic regression models were used to identify independent predictors of long-term mortality. A total of 3,050 subjects underwent surgery. Mean age was 60.8 years, and 59% were women. Postoperative troponin was measured in 1,055 subjects (34.6%). Myocardial necrosis occurred in 179 cases (5.9%), and MI was coded in 20 (0.7%). Over 9,015 patient-years of follow-up, 111 deaths (3.6%) occurred. Long-term mortality was 16.8% in subjects with myocardial necrosis and 5.8% with a troponin in the normal range. Perioperative troponin elevation (hazard ratio 2.33, 95% confidence interval 1.33 to 4.10) and coded postoperative MI (adjusted hazard ratio 3.51, 95% confidence interval 1.44 to 8.53) were significantly associated with long-term mortality after multivariable adjustment. After excluding patients with coronary artery disease and renal dysfunction, myocardial necrosis remained associated with long-term mortality. In conclusion, postoperative myocardial necrosis is common after orthopedic surgery. Myocardial necrosis is independently associated with long-term mortality at 3 years and may be used to identify patients at higher risk for events who may benefit from aggressive management of cardiovascular risk factors.

BACKGROUND CONTEXT: Vertebral compression fractures secondary to low bone mass are responsible for almost 130,000 inpatient admissions and 133,500 emergency department visits annually, totaling over $5 billion of direct inpatient costs. Although most vertebral compression fractures heal within a few months with conservative therapy, a significant portion fail to improve with conservative treatment and require long-term care, conservative treatment, or both. Fractures that fail conservative therapy are treated with vertebral augmentation procedures (VAPs) such as vertebroplasty (VP) and kyphoplasty (KP). Two large randomized clinical trials published in 2009 questioned the efficacy of VP in treatment of VAPs. PURPOSE: This study aimed to investigate trends in utilization of VP and KP between 2005 and 2010 to capture the impact of the 2009 literature on utilization of VAPs. The study also compares patient characteristics and perioperative outcomes between VP and KP to further delineate the risks of each procedure. STUDY DESIGN: Retrospective analysis of national utilization rates, clinical outcomes, patient demographics, and patient comorbidities using a large national inpatient database. PATIENT SAMPLE: A total of 63,459 inpatient admissions from 46 states and more than 1,000 different hospitals were included in the analysis. OUTCOME MEASURES: Length of stay (LOS), total direct cost, mortality, postoperative complications. METHODS: Data were obtained from the National Inpatient Sample database for the period between 2005 and 2010. National Inpatient Sample is the largest publicly available all payer inpatient database in the United States. Patients undergoing VP and KP were identified via corresponding the International Classification of Diseases, 9th Revision procedure codes. National utilization trends were estimated using weights supplied as part of the National Inpatient Sample dataset. Information on patient comorbidities and demographics was collected. A series of univariate and multivarariate analyses were used to identify statistically significant differences in patient characteristics, clinical outcomes, as well as cost and LOS between patients undergoing VP versus KP. RESULTS: A total of 307,050 inpatient VAPs were performed in the United States between 2005 and 2010. Of those procedures, 225,259 were KP and 81,790 were VP. Kyphoplasty utilization showed an increasing trend between 2005 and 2007, increasing from 27 to 33 procedures per 100,000 capita older than 40 years. During the same time period, VP utilization remained constant at approximately nine procedures per 100,000 capita older than 40 years. After 2007, utilization of both VP and KP decreased. The most precipitous decrease in VAP utilization occurred in 2009. Patients undergoing VP were on average older (76.7 vs. 77.8, p<.0001), more frequently women (74.48% vs. 73.15%, p=.00083), and black (1.77% vs. 1.55%, p=.004059). Patients undergoing VP had on average more comorbidities then those undergoing KP. Patients undergoing VP had a higher rate of postoperative anemia secondary to acute bleeding and higher rate of venous thromboembolic events. Those undergoing KP had a greater rate of cardiac complications; however, this difference was not statistically significant when taking into account patient age and comorbidity burden. Vertebroplasty was associated with higher mortality (0.93% vs. 0.60%, p<.001), longer LOS (6.78 vs. 5.05 days, p<.0001), and lower total cost ($42,154 vs. $46,101, p<.0001). CONCLUSIONS: Overall, KP was associated with lower complication rates, shorter LOS, and a higher total direct cost compared with VP. Utilization rates showed a significant decrease since 2009 in both VP and KP, suggesting that both procedures were impacted by the two randomized controlled trials published in 2009 that suggested poor efficacy of VP.