Michael H. Weber

Surgical site infection in spinal surgery: description of surgical and patient-based risk factors for postoperative infection using administrative claims data.

Study Design. Retrospective analysis. Objective. The objective of this study was to investigate the accuracy of using an automated approach to administrative claims data to assess the rate and risk factors for surgical site infection (SSI) in spinal procedures. Summary of Background Data. SSI is a major indicator of health care quality. A wide range of SSI rates have been proposed in the literature depending on clinical setting and procedure type. Methods. All spinal surgeries performed at a university-affiliated tertiary-care center from July 2005 to December 2010 were identified using diagnosis-related group, current procedural terminology, and International Classification of Diseases, Ninth Revision (ICD-9) codes and were validated through chart review. Rates of SSI and associated risk factors were calculated using univariate regression analysis. Odds ratios were calculated through multivariate logistic regression. Results. A total of 6628 hospital visits were identified. The cumulative incidence of SSI was 2.9%. Procedural risk factors associated with a statistically significant increase in rates of infection were the following: sacral involvement (9.6%), fusions greater than 7 levels (7.8%), fusions greater than 12 levels (10.4%), cases with an osteotomy (6.5%), operative time longer than 5 hours (5.1%), transfusions of red blood cells (5.0%), serum (7.4%), and autologous blood (4.1%). Patient-based risk factors included anemia (4.3%), diabetes mellitus (4.2%), coronary artery disease (4.7%), diagnosis of coagulopathy (7.8%), and bone or connective tissue neoplasm (5.0%). Conclusion. Used individually, diagnosis-related group, current procedural terminology, and ICD-9 codes cannot completely capture a patient population. Using an algorithm combining all 3 coding systems to generate both inclusion and exclusion criteria, we were able to analyze a specific population of spinal surgery patients within a high-volume medical center. Within that group, risk factors found to increase infection rates were isolated and can serve to focus hospital-wide efforts to decrease surgery-related morbidity and improve patient outcomes.

Painful, degenerating intervertebral discs up-regulate neurite sprouting and CGRP through nociceptive factors

Intervertebral disc degeneration (IVD) can result in chronic low back pain, a common cause of morbidity and disability. Inflammation has been associated with IVD degeneration, however the relationship between inflammatory factors and chronic low back pain remains unclear. Furthermore, increased levels of nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) are both associated with inflammation and chronic low back pain, but whether degenerating discs release sufficient concentrations of factors that induce nociceptor plasticity remains unclear. Degenerating IVDs from low back pain patients and healthy, painless IVDs from human organ donors were cultured ex vivo. Inflammatory and nociceptive factors released by IVDs into culture media were quantified by enzyme‐linked immunosorbent assays and protein arrays. The ability of factors released to induce neurite growth and nociceptive neuropeptide production was investigated. Degenerating discs release increased levels of tumour necrosis factor‐α, interleukin‐1β, NGF and BDNF. Factors released by degenerating IVDs increased neurite growth and calcitonin gene‐related peptide expression, both of which were blocked by anti‐NGF treatment. Furthermore, protein arrays found increased levels of 20 inflammatory factors, many of which have nociceptive effects. Our results demonstrate that degenerating and painful human IVDs release increased levels of NGF, inflammatory and nociceptive factors ex vivo that induce neuronal plasticity and may actively diffuse to induce neo‐innervation and pain in vivo.

Perioperative Outcomes and Complications of Pedicle Subtraction Osteotomy in Cases With Single Versus Two Attending Surgeons.

STUDY DESIGN Retrospective case series. OBJECTIVE To assess the perioperative morbidity of pedicle subtraction osteotomy (PSO) based on the presence of 1 versus 2 attending surgeons. BACKGROUND SUMMARY Pedicle subtraction osteotomies are challenging cases with high complication rates and substantial physiological burden on patients. The literature supports the benefits of 2-surgeon strategies in complex cases in other specialties. METHODS We reviewed a single institution database of all pedicle subtraction osteotomies (78 cases) from 2005-2010 and divided the cohort into single versus 2-surgeon groups (42 vs. 36 cases, respectively). We performed subset analysis after excluding cases before 2007 and excluding patients with staged anterior and posterior procedures. We analyzed cases for estimated blood loss, length of surgery, length of stay, radiographic analysis, rate of return to the operating room within 30 days, and medical and neurological complications. RESULTS The groups were similar when comparing mean number of posterior levels fused, levels decompressed and revision rates, however, the average age of the single surgeon and 2 surgeon groups was 57.6 and 64.3 years, respectively (p = .02). The 2 groups had comparable correction of radiographic parameters. Mean percent estimated blood loss for single versus 2 surgeons was 109% versus 35% (p < .001) and estimated blood loss was 5,278 versus 2,003 mL (p < .001). Average surgical time for single versus 2 surgeons was 7.6 versus 5.0 hours (p < .001). A total of 45% of single-surgeon patients compared with 25% of 2-surgeon patients experienced at least 1 major complication within 30 days. In the single-surgeon group, 19% had unplanned surgery within 30 days, versus 8% in the 2-surgeon group. CONCLUSIONS The use of 2 surgeons at an experienced spine deformity center decreases the operative time and estimated blood loss, and may be a key factor in witnessed decreased major complication prevalence. This approach also may decrease the rate of premature case termination and return to operating room in 30 days.

Value-based care in the management of spinal disorders: a systematic review of cost-utility analysis.

BackgroundSpinal disorders are a major cause of disability and compromise in health-related quality of life. The direct and indirect costs of treating spinal disorders are estimated at more than

Nerve Growth Factor Is Regulated by Toll-Like Receptor 2 in Human Intervertebral Discs

100 billion per year. With limited resources, the cost-utility of interventions is important for allocating resources.Questions/purposesWe therefore performed a systematic review of the literature on cost-utility for nonoperative and operative interventions for treating spinal disorders.MethodsWe searched four databases for cost-utility analysis studies on low back pain management and identified 1004 items. The titles and abstracts of 752 were screened before selecting 27 studies for inclusion; full texts of these 27 studies were individually evaluated by five individuals.ResultsStudies of nonoperative treatments demonstrated greater value for graded activity over physical therapy and pain management; spinal manipulation over exercise; behavioral therapy and physiotherapy over advice; and acupuncture and exercise over usual general practitioner care. Circumferential fusion and femoral ring allograft had greater value than posterolateral fusion and titanium cage, respectively. The relative cost-utility of operative versus nonoperative interventions was variable with the most consistent evidence indicating superior value of operative care for treating spinal disorders involving nerve compression and instability.ConclusionThe literature on cost-utility for treating spinal disorders is limited. Studies addressing cost-utility of nonoperative and operative management of low back pain encompass a broad spectrum of diagnoses and direct comparison of treatments based on cost-utility thresholds for comparative effectiveness is limited by diversity among disorders and methods to assess cost-utility. Future research will benefit from uniform methods and comparison of treatments in cohorts with well-defined pathology.

Predictors of Discharge Destination After Lumbar Spine Fusion Surgery

Nerve growth factor (NGF) contributes to the development of chronic pain associated with degenerative connective tissue pathologies, such as intervertebral disc degeneration and osteoarthritis. However, surprisingly little is known about the regulation of NGF in these conditions. Toll-like receptors (TLR) are pattern recognition receptors classically associated with innate immunity but more recently were found to be activated by endogenous alarmins such as fragmented extracellular matrix proteins found in degenerating discs or cartilage. In this study we investigated if TLR activation regulates NGF and which signaling mechanisms control this response in intervertebral discs. TLR2 agonists, TLR4 agonists, or IL-1β (control) treatment increased NGF, brain-derived neurotrophic factor (BDNF), and IL-1β gene expression in human disc cells isolated from healthy, pain-free organ donors. However, only TLR2 activation or IL-1β treatment increased NGF protein secretion. TLR2 activation increased p38, ERK1/2, and p65 activity and increased p65 translocation to the cell nucleus. JNK activity was not affected by TLR2 activation. Inhibition of NF-κB, and to a lesser extent p38, but not ERK1/2 activity, blocked TLR2-driven NGF up-regulation at both the transcript and protein levels. These results provide a novel mechanism of NGF regulation in the intervertebral disc and potentially other pathogenic connective tissues. TLR2 and NF-κB signaling are known to increase cytokines and proteases, which accelerate matrix degradation. Therefore, TLR2 or NF-κB inhibition may both attenuate chronic pain and slow the degenerative progress in vivo.

Adjacent Segment Degeneration Versus Disease After Lumbar Spine Fusion for Degenerative Pathology: A Systematic Review With Meta-Analysis of the Literature.

Study Design. Retrospective cohort study of the prospective collected American College of Surgeons National Surgical Quality Improvement Program database. Objective. The aim of the study was to identify predictive factors for the need of discharging patients to a facility other than home after lumbar spine fusion surgery. Summary of Background Data. Lumbar spine fusion surgery is a common surgical procedure used to treat a variety of lumbar spine conditions. A great number of patients fail to go home after surgery and require admission to a rehabilitation center. Predictive factors for discharging patients to a facility other than home after lumbar fusion surgery do not exist in the literature. Methods. A total of 15,092 patients undergoing lumbar spine fusion were dichotomized based on discharge destination to patients who were discharged home (N = 12,339) and others who were discharged to a facility other than home (N = 2753). Outcomes included patient demographics, comorbidities, and clinical characteristics. A multivariate logistic regression was used to identify whether outcomes studied were predictive factors for discharging patients to a facility other than home after lumbar fusion surgery. Results. Majority of patients were discharged home after lumbar fusion surgery (81.76%), with only some discharged to a facility other than home (18.24%). Multivariate analysis identified age, female sex, comorbidities (diabetes, chronic obstructive pulmonary disease, congestive heart failure, hypertension, and obesity), minor and major complications, hospital length of stay, operative time at least 259 minutes, and multilevel surgery as significant predictive factors of discharging patients to a facility other than home after lumbar fusion surgery. Conclusion. The identified predictive factors can help the health system in developing an algorithm for early recognition of patients requiring postoperative admission to a facility other than home and possibly decreasing their hospital length of stay. This can significantly decrease the hospital costs for such patients. Level of Evidence: 3

The Relationship between Preoperative Expectations and the Short-Term Postoperative Satisfaction and Functional Outcome in Lumbar Spine Surgery: A Systematic Review

Study Design: A systematic review. Objective: The purpose of this study was to review the published literature to estimate rates and identify risk factors for adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDis) after lumbar fusion. Summary of Background Data: Arthrodesis remains a common intervention for the surgical treatment of degenerative spinal disease. Clinical studies have demonstrated variability in the rates of adjacent segment pathology after lumbar fusion. Methods: This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Symptoms of ASDis were distinguished and defined by the need for a revision surgery procedure to address adjacent level pathology. We searched MEDLINE, EMBASE, Cochrane Library, and CINAHL databases. Extracted data included average patient age, average time to follow-up, type of intervention, potential risk factors, and ASDeg and ASDis incidence. Funnel and forest plots were used to describe heterogeneity and meta-regression to estimate pooled incidence of ASDeg and ASDis. Results: A total of 31 articles with 4206 patients were included for analysis. Combining all extractable data, the overall pooled incidence of ASDeg was 5.9% per year (95% CI, 4.8%, 7.2%), and ASDis was 1.8% (95% CI, 1.3%, 2.4%) per year. The incidence of ASDeg is higher with more motion segments. Sex, age, segmental sagittal alignment, fusion methods, and instrumentation were not associated with an increased risk of ASDeg or ASDis. Radiographic ASDeg did not show strong correlation with clinical outcomes. Conclusions: The prevalence of ASDeg and ASDis has been variably reported in the literature, and fusion length is the factor most significantly associated with adjacent segment pathology. In guiding surgical strategies to avoid adjacent segment pathology, limiting the number of levels fused may have a greater impact than changes in fusion strategies.

Incidence, Predictors, and Postoperative Complications of Blood Transfusion in Thoracic and Lumbar Fusion Surgery: An Analysis of 13,695 Patients from the American College of Surgeons National Surgical Quality Improvement Program Database

Study Design Systematic review. Objective To examine the relationship between the patients preoperative expectations and short-term postoperative satisfaction and functional outcome in lumbar spine surgery. Methods The Medline, Embase, and Cochrane databases were queried using a predefined search algorithm to identify all lumbar spine studies analyzing the influence of preoperative expectations on postoperative satisfaction and functional outcome. Two independent reviewers and a third independent mediator reviewed the literature and performed study screening, selection, methodological assessment, and data extraction using an objective protocol. Results Of 444 studies identified, 13 met the inclusion criteria. Methodological quality scores ranged from 59 to 100% with the greatest variability in defining patient characteristics and the methods of assessing patient expectations. Patient expectations were assessed in 22 areas, most frequently back and leg pain expectations and general expectations. Functional outcome was assessed by 13 tools; the most common were the visual analog scale, Oswestry Disability Index (ODI), and Short Form Health Survey (SF-36). Positive expectations for symptomatology, activity, general health, and recovery correlated with satisfaction. General expectations correlated with higher SF-36 Physical Subcomponent scores, better global function, and lower ODI outcome. Conclusions on the influence of the expectations for pain were limited due to the study heterogeneity, but the evidence suggests a positive correlation between the expectation and outcome for back and leg pain. Conclusions Positive expectations correlated significantly with short-term postoperative satisfaction and functional outcome, including higher SF-36 scores, earlier return to work, and decreased ODI scores. Future expectation-based investigations will benefit from implementation of the standardized methods of expectation, satisfaction, and outcome analysis discussed herein.

A Systematic Review of Clinical Outcomes and Prognostic Factors for Patients Undergoing Surgery for Spinal Metastases Secondary to Breast Cancer.

Study Design Retrospective cohort study. Objective To identify predictive factors for blood transfusion and associated complications in lumbar and thoracic fusion surgeries. Methods The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients who underwent lumbar or thoracic fusion from 2010 to 2013. Multivariate analysis was used to determine predictive factors and postoperative complications associated with transfusion. Results Out of 13,695 patients, 13,170 had lumbar fusion and 525 had thoracic fusion. The prevalence of transfusion was 31.8% for thoracic and 17.0% for lumbar fusion. The multivariate analysis showed that age between 50 and 60, age between 61 and 70, age > 70, dyspnea, American Society of Anesthesiologists class 3, bleeding disease, multilevel surgery, extended surgical time, return to operation room, and higher preoperative blood urea nitrogen (BUN) were predictors of blood transfusion for lumbar fusion. Multilevel surgery, preoperative BUN, and extended surgical time were predictors of transfusion for thoracic fusion. Patients receiving transfusions who underwent lumbar fusion were more likely to develop wound infection, venous thromboembolism, pulmonary embolism, and myocardial infarction and had longer hospital stay. Patients receiving transfusions who underwent thoracic fusion were more likely to have extended hospital stay. Conclusion This study characterizes incidence, predictors, and postoperative complications associated with blood transfusion in thoracic and lumbar fusion. Pre- and postoperative planning for patients deemed to be at high risk of requiring blood transfusion might reduce postoperative complications in this population.