Faculty Bibliography

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.

BACKGROUND: Unplanned hospital readmissions result in significant clinical and financial burdens to patients and the healthcare system. Readmission rates and causes have been investigated using large administrative databases which have certain limitations in data reporting and coding. The objective of this study was to provide a description of 90 day post-discharge readmissions following surgery for common degenerative cervical spine pathologies at a large-volume tertiary hospital. The study also compared the readmission rates of patients who underwent anterior- and posterior-approach procedures. METHODS: The administrative records from a single-center, high-volume tertiary institution were queried using ICD-9 codes for common cervical pathology over a three year period to determine the rate and causes of readmissions within the 90 days following the index surgery. RESULTS: A total of 768 patients underwent degenerative cervical spine surgery during the three year study period. Within 90 days of discharge, 24 (3.13%) patients were readmitted; 16 (2.06%) readmissions were planned for lumbar surgery; 8 (1.04%) readmissions were unplanned. 640 patients underwent procedures involving an anterior approach and 128 patients underwent procedures involving a posterior approach. There were 14 (2.17%) planned readmissions in the anterior group and 2 (1.5%) in the posterior group. The unplanned readmission rate was 0.63% (4 patients) and 3.13% (4 patients) in the anterior and posterior groups, respectively. (p=0.0343). CONCLUSION: The 90 day post-discharge unplanned readmission rate that followed elective degenerative cervical spine surgery was 1.04%. The unplanned readmission rate associated with posterior-approach procedures (3.13%) was significantly higher than that of anterior-approach procedures (0.63%). LEVEL OF EVIDENCE: IV.

STUDY DESIGN: This is a prospective, randomized, double-blinded comparison of tranexamic acid (TXA), epsilon aminocaproic acid (EACA), and placebo used intraoperatively in patients with adult spinal deformity. OBJECTIVE: The purpose of this study was to provide high-quality evidence regarding the comparative efficacies of TXA, EACA, and placebo in reducing blood loss and transfusion requirements in patients undergoing posterior spinal fusion surgery. SUMMARY OF BACKGROUND DATA: Spine deformity surgery usually involves substantial blood loss. The antifibrinolytics TXA and EACA have been shown to improve hemostasis in large blood loss surgical procedures. METHODS: Fifty-one patients undergoing posterior spinal fusion of at least 5 levels for correction of adult spinal deformity were randomized to 1 of 3 treatment groups. Primary outcome measures included intraoperative estimated blood loss, total loss, (estimated blood loss + postoperative blood loss), and transfusion rates. RESULTS: Patients received TXA (n = 19), EACA (n = 19), or placebo (n = 13) in the operating room (mean ages: 60, 47, and 43 yr, respectively); TXA patients were significantly older and had larger estimated blood volumes than both other groups. Total losses were significantly reduced for EACA versus control, and there was a demonstrable but nonsignificant trend toward reduced intraoperative blood loss in both antifibrinolytic arms versus control. EACA had significant reductions in postoperative blood transfusions versus TXA. CONCLUSION: The findings in this study support the use of antifibrinolytics to reduce blood loss in posterior adult spinal deformity surgery. LEVEL OF EVIDENCE: 1.

BACKGROUND CONTEXT: Revision adult spinal deformity surgery (RASDS) is a particularly high-risk intervention. PURPOSE: To assess complication rates in RASDS by surgeon and hospital operative volume. STUDY DESIGN/ SETTING: Retrospective analysis of prospectively collected data. PATIENT SAMPLE: Nationwide Inpatient Sample (NIS) database (2001-2010), patients age >21 (International Classification of Diseases, Ninth Revision, ICD-9-CM) with spine arthrodesis for scoliosis. For longitudinal analysis, the 2008-2011 New York State Inpatient Database (NY SID) was queried. OUTCOME MEASURES: Complication rate after RASDS METHODS: Cases were identified as primary or revision surgery with or without osteotomy performed. Annual surgeon and hospital volumes were stratified into quartiles via identifier codes. Case complexity was determined using a novel operative complexity index, based on available NIS operative parameters: levels fused, approach, osteotomy and revision status.. The primary endpoint for was morbidity during the hospital stay. NY SID analysis allowed for identification of rate of reoperation for infection or pseudarthrosis/implant failure. One-way ANOVA was used to assess continuous measures, chi-square for categorical measures. RESULTS: Of 139,150 ASDS cases, 4,888 revision with hospital identifiers and 1,978 with surgeon identifiers were identified. Higher volume surgeons performed more revision cases and cases requiring osteotomy. With increasing hospital volume, complication rate for RASDS decreased (9.7% vs. 12.9% at highest- vs. lowest-volume centers, P< 0.001). The highest-volume surgeons showed significant decreases in the rate of major complications for RASDS (8.8% vs. 10.7% for lowest volume surgeons, P< 0.001). A similar trend was observed for ASDS cases requiring osteotomy. Multiple logistic regression analysis showed that the highest volume hospitals and surgeons showed a reduced odds ratio for all complications compared to lowest volume. For the NY SID, 528 RASDS cases indicated reoperation rates for infection and pseudoarthrosis/implant failure after RASDS were increased for the lowest volume hospitals and surgeons. CONCLUSION: Perioperative complication rate associated with RASDS is lower when patients are treated by high-volume surgeons at high-volume centers. As complex cases requiring osteotomy and combined approaches are more frequent at high-volume centers, an operative complexity index helps predict the likelihood of volume-dependent complication rates. Future inter-hospital and inter-surgeon comparisons should account for these case characteristics so that similar case complexity is compared in these analyses.

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.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To assess the rate and causes of unplanned readmissions after surgical treatment of common degenerative lumbar pathologies within 90 days. SUMMARY OF BACKGROUND DATA: With pay-for performance and bundled payment compensation models being implemented; there is a growing emphasis to decrease the number of unplanned readmissions after surgery. Reports on degenerative lumbar spine pathology readmission rates are often obtained from national databases that lack clinical detail. Less published are the results from single-center institutions. METHODS: Hospital administrative database from a single-tertiary institution was queried to identify patients who underwent surgery for 6 common lumbar pathologies during a period from 2011 to 2013. All readmissions within 90 days of discharge were reviewed for cause and rate of unplanned readmissions was calculated. RESULTS: A total of 1306 patients were identified who underwent surgery for various lumbar pathologies during a 2-year time period. There were a total of 70 readmissions captured in the database that included 14 planned, 43 unplanned readmissions, and 13 coding errors. The unplanned readmission rate varied between 2.1% and 7.1% depending on pathology, with an overall rate of 3.3% within 90 days of discharge. Index length of stay, discharge disposition, severity of illness scores, and surgical approach were associated with readmission. The addition of fusion to decompression procedures did not seem to increase readmission rates. Surgical site infections and wound complications were the 2 most common reasons for readmissions accounting for 72% of all readmissions during the 90-day postdischarge period. CONCLUSION: The rate of readmission after surgery for common lumbar degenerative pathologies is relatively low. Surgical site infections and wound complications were the most common cause of readmission in this patient cohort. LEVEL OF EVIDENCE: 4.

: Study Design. Retrospective review, full body radiographic analysis of adult patients with sagittal spinal malalignment.Objective. Investigate the compensatory mechanisms involved in the sagittal plane of the body following progressive spinal sagittal malalignment, and study the impact of age on compensatory mechanisms recruitment.Summary of Background Data. Sagittal spinal malalignment (SSM) patients recruit compensatory mechanisms to maintain erect posture and horizontal gaze. Mechanisms such as pelvic retroversion, knee flexion and pelvic shift have been proposed, but how they contribute and how age affects their recruitment is poorly understood.Methods. Retrospective review of adult SSM patients who underwent full standing axis stereoradiography EOS(c). Radiographic measurements were performed with Surgimap(c). Patients were categorized based on the mismatch between pelvic incidence and lumbar lordosis (PI-LL). Compensatory mechanisms were normalized to each patient's PI-LL and compared by mismatch groups. In addition, patients were subcategorized into two age groups (>/=65yrs and <65yrs) and compared within the same groups of mismatch.Results. 161 patients with a mean age of 62.93+/-12.8yrs. Mean SVA 62.3+/-61.5mm, PT 29.2+/-8.4 degrees , and PI-LL 21.0+/-14.9 degrees . Mismatch groups were: Group 1: PI-LL 0-10 degrees , Group 2: 10-20 degrees , Group 3: 20-30 degrees , and Group 4: > 30 degrees . There were significant differences between all groups in regards to thoracic kyphosis (TK), pelvic tilt (PT), knee flexion angle (KA), and pelvic shift (P.Sh) by ANOVA (p<0.001). As PI-LL increased, TK and PT contribution to the compensation cascade decreased and KA and P.Sh contribution increased. Patients with PI-LL of > 30 degrees who were older had significantly less PT and more TK than patients with similar PI-LL who were younger.Conclusions. Spino-pelvic mismatch is an important driver in SSM. Pelvic retroversion and flattening of thoracic kyphosis (reduction) become exhausted with increasing mismatch, at which point there appears to be a steady transfer of compensation towards significant participation of the lower limbs. Further analysis suggests differential recruitment of these compensatory mechanisms based upon age.