Health Care Utilization and Associated Economic Burden of Postoperative Surgical Site Infection after Spinal Surgery with Follow-Up of 24 Months.

BACKGROUND: Surgical site infection (SSI) may lead to vertebral osteomyelitis, diskitis, paraspinal musculoskeletal infection, and abscess, and remains a significant concern in postoperative management of spinal surgery. SSI is associated with greater postoperative morbidity and increased health care payments. METHODS: We conducted a retrospective analysis using MarketScan to identify health care utilization payments and risk factors associated with SSI that occurs postoperatively. Known patient- or procedure-related risk factors were searched across those receiving spine surgery who developed postoperative infection. RESULTS: A total of 33,061 patients who developed infection after spinal surgery were identified in Marketscan. Overall payments at 6 months, including index hospitalization for those with infection, were $53,573 and $46,985 for the cohort with no infection. At 24 months, the infection group had overall payments of $83,280 and $66,221 for no infection. Risk factors with largest effect size most likely to contribute to infection versus no infection were depression (4.6%), diabetes (3.7), anemia (3.3%), two or more levels (2.8%), tobacco use (2.2%), trauma (2.1%), neoplasm (1.8%), congestive heart failure (1.3%), instrumentation (1.1%), renal failure (0.9%), intravenous drug use (0.8%), and malnutrition (0.5%). CONCLUSIONS: SSIs were associated with significant health care utilization payments at 24 months of follow-up. The following clinical and procedural risk factors appear to be predictive of postoperative SSI: depression, diabetes, anemia, two or more levels, tobacco use, trauma, neoplasm, congestive heart failure, instrumentation, renal failure, intravenous drug use, and malnutrition. Interpretation of modifiable and nonmodifiable risk factors for infection informs surgeons of expected postoperative course and preoperative risk for this most common and deleterious postoperative complication to spinal surgery.

Trajectory-Based Classification of Recovery in Sensorimotor Complete Traumatic Cervical Spinal Cord Injury.

OBJECTIVE: To test the hypothesis that sensorimotor complete traumatic cervical spinal cord injury is a heterogenous clinical entity comprising several subpopulations that follow fundamentally different trajectories of neurologic recovery. METHODS: We analyzed demographic and injury data from 655 patients who were pooled from 4 prospective longitudinal multicenter studies. Group based trajectory modeling was applied to model neurologic recovery trajectories over the initial 12-months postinjury and to identify predictors of recovery trajectories. Neurologic outcomes included: Upper Extremity Motor Score, Total Motor Scores and AIS grade improvement. RESULTS: The analysis identified 3 distinct trajectories of neurologic recovery. These clinical courses included: (1) Marginal recovery trajectory: characterized by minimal or no improvement in motor strength or change in AIS grade status (remained grade A); (2) Moderate recovery trajectory: characterized by low baseline motor scores that improved approximately 13 points; or AIS conversion of one grade point; (3) Good recovery trajectory: characterized by baseline motor scores in the upper quartile that improved to near maximum values within 3 months of injury. Patients following the moderate or good recovery trajectories were of younger age, had more caudally located injuries, a higher degree of preserved motor and sensory function at baseline examination and exhibited a greater extent of motor and sensory function in the zone of partial preservation. CONCLUSION: Cervical complete SCI can be classified into one of 3 distinct subpopulations with fundamentally different trajectories of neurologic recovery. This study defines unique clinical phenotypes based on potential for recovery, rather than baseline severity of injury alone. This approach may prove beneficial in clinical prognostication and in the design and interpretation of clinical trials in SCI.

Characterization of Lower Urinary Tract Dysfunction after Thoracic Spinal Cord Injury in Yucatan Minipigs.

There is an increasing need to develop approaches that will not only improve the clinical management of neurogenic lower urinary tract dysfunction (NLUTD) after spinal cord injury (SCI), but also advance therapeutic interventions aimed at recovering bladder function. Although pre-clinical research frequently employs rodent SCI models, large animals such as the pig may play an important translational role in facilitating the development of devices or treatments. Therefore, the objective of this study was to develop a urodynamics protocol to characterize NLUTD in a porcine model of SCI. An iterative process to develop the protocol to perform urodynamics in female Yucatan minipigs began with a group of spinally intact, anesthetized pigs. Subsequently, urodynamic studies were performed in a group of awake, lightly restrained pigs, before and after a contusion-compression SCI at the T2 or T9-T11 spinal cord level. Bladder tissue was obtained for histological analysis at the end of the study. All anesthetized pigs had bladders that were acontractile, which resulted in overflow incontinence once capacity was reached. Uninjured, conscious pigs demonstrated appropriate relaxation and contraction of the external urethral sphincter during the voiding phase. SCI pigs demonstrated neurogenic detrusor overactivity and a significantly elevated post-void residual volume. Relative to the control, SCI bladders were heavier and thicker. The developed urodynamics protocol allows for repetitive evaluation of lower urinary tract function in pigs at different time points post-SCI. This technique manifests the potential for using the pig as an intermediary, large animal model for translational studies in NLUTD.

Evaluation of Predictive Models for Complications following Spinal Surgery.

BACKGROUND: Complications rates vary across spinal surgery procedures and are difficult to predict due to heterogeneity in patient characteristics, surgical methods, and hospital volume. Incorporation of predictive models for complications may guide surgeon decision making and improve outcomes. METHODS: We evaluate current independently validated predictive models for complications in spinal surgery with respect to study design and model generation, accuracy, reliability, and utility. We conducted our search using Preferred Reporting Items for Systematic Review and Meta-analysis guidelines and the Participants, Intervention, Comparison, Outcomes, Study Design model through the PubMed and Ovid Medline databases. RESULTS: A total of 18 articles met inclusion criteria including 30 validated predictive models of complications after adult spinal surgery. National registry databases were used in 12 studies. Validation cohorts were used in seven studies for verification; three studies used other methods including random sample bootstrapping techniques or cross-validation. Reported area under the curve (AUC) values ranged from 0.37 to 1.0. Studies described treatment for deformity, degenerative conditions, inclusive spinal surgery (neoplasm, trauma, infection, deformity, degenerative), and miscellaneous (disk herniation, spinal epidural abscess). The most commonly cited risk factors for complications included in predictive models included age, body mass index, diabetes, sex, and smoking. Those models in the deformity subset that included radiographic and anatomical grading features reported higher AUC values than those that included patient demographics or medical comorbidities alone. CONCLUSIONS: We identified a cohort of 30 validated predictive models of complications following spinal surgery for degenerative conditions, deformity, infection, and trauma. Accurate evidence-based predictive models may enhance shared decision making, improve rehabilitation, reduce adverse events, and inform best practices.

Acute Adverse Events After Spinal Cord Injury and Their Relationship to Long-term Neurologic and Functional Outcomes: Analysis From the North American Clinical Trials Network for Spinal Cord Injury.

OBJECTIVES: There are few contemporary, prospective multicenter series on the spectrum of acute adverse events and their relationship to long-term outcomes after traumatic spinal cord injury. The goal of this study is to assess the prevalence of adverse events after traumatic spinal cord injury and to evaluate the effects on long-term clinical outcome. DESIGN: Multicenter prospective registry. SETTING: Consortium of 11 university-affiliated medical centers in the North American Clinical Trials Network. PATIENTS: Eight-hundred one spinal cord injury patients enrolled by participating centers. INTERVENTIONS: Appropriate spinal cord injury treatment at individual centers. MEASUREMENTS AND MAIN RESULTS: A total of 2,303 adverse events were recorded for 502 patients (63%). Penalized maximum logistic regression models were fitted to estimate the likelihood of neurologic recovery (ASIA Impairment Scale improvement ≥ 1 grade point) and functional outcomes in subjects who developed adverse events at 6 months postinjury. After accounting for potential confounders, the group that developed adverse events showed less neurologic recovery (odds ratio, 0.55; 95% CI, 0.32-0.96) and was more likely to require assisted breathing (odds ratio, 6.55; 95% CI, 1.17-36.67); dependent ambulation (odds ratio, 7.38; 95% CI, 4.35-13.06) and have impaired bladder (odds ratio, 9.63; 95% CI, 5.19-17.87) or bowel function (odds ratio, 7.86; 95% CI, 4.31-14.32) measured using the Spinal Cord Independence Measure subscores. CONCLUSIONS: Results from this contemporary series demonstrate that acute adverse events are common and are associated with worsened long-term outcomes after traumatic spinal cord injury.

Association of Pneumonia, Wound Infection, and Sepsis with Clinical Outcomes after Acute Traumatic Spinal Cord Injury.

Pneumonia, wound infections, and sepsis (PWS) are the leading causes of acute mortality after traumatic spinal cord injury (SCI). However, the impact of PWS on neurological and functional outcomes is largely unknown. The present study analyzed participants from the prospective North American Clinical Trials Network (NACTN) registry and the Surgical Timing in Acute SCI Study (STASCIS) for the association between PWS and functional outcome (assessed as Spinal Cord Independence Measure subscores for respiration and indoor ambulation) at 6 months post-injury. Neurological outcome was analyzed as a secondary end-point. Among 1299 participants studied, 180 (14%) developed PWS during the acute admission. Compared with those without PWS, participants with PWS were mostly male (76% vs. 86%; p = 0.007), or presented with mostly American Spinal Injury Association Impairment Scale (AIS) grade A injury (36% vs. 61%; p < 0.001). There were no statistical differences between participants with or without PWS with respect to time from injury to surgery, and administration of steroids. Dominance analysis showed injury level, baseline AIS grade, and subject pre-morbid medical status collectively accounted for 77.7% of the predicted variance of PWS. Regression analysis indicated subjects with PWS demonstrated higher odds for respiratory (odds ratio [OR] 3.91, 95% confidence interval [CI]: 1.42-10.79) and ambulatory (OR 3.94, 95% CI: 1.50-10.38) support at 6 month follow-up in adjusted analysis. This study has shown an association between PWS occurring during acute admission and poorer functional outcomes following SCI.

Patterns of Care and Outcomes of Adjuvant Radiotherapy for Meningiomas: A Surveillance, Epidemiology, and End Results and Medicare Linked Analysis.

BACKGROUND: The role of adjuvant stereotactic radiosurgery (SRS) and fractionated radiotherapy (XRT) are unknown in patients with resected meningiomas. OBJECTIVE: To identify patterns of care and outcomes of adjuvant radiotherapy for meningiomas in the Linked Surveillance, Epidemiology, and End Results (SEER) Medicare data. METHODS: A total of 1,964 patients older than 66 years included in the SEER-Medicare data, who were diagnosed with meningioma, and underwent craniotomy were included for analysis. RESULTS: Patients were less likely to receive adjuvant therapy if they were older than 75 (OR 0.730, 95% CI 0.548-0.973), female sex (OR 0.731, 95% CI 0.547-0.978), or unmarried (OR 0.692, 95% CI 0.515-0.929). Patients were more likely to receive adjuvant treatment for Grade II/III tumors (OR 5.586, 95% CI 2.135-13.589), tumors over 5 cm (OR 1.850, 95% CI 1.332-2.567), or partial resection (OR 3.230, 95% CI 2.327-4.484). Yearly between 2000 and 2009, 10.65 - 19.77% of patients received adjuvant therapy. Although no survival benefit was seen with the addition of adjuvant therapy (p = 0.1236), the subgroup of patients receiving SRS had a decreased risk of death compared to those receiving surgery alone (aHR 0.544, 95% CI 0.318 - 0.929). CONCLUSION: Utilization of adjuvant XRT and SRS remained stable between 2000 and 2010. Male sex, young age, marriage, partial resection, Grade II/III tumors, and large tumors predicted the use of adjuvant therapy. For all patients, SRS decreased the risk of death compared to craniotomy alone.