Long-term Corticosteroid Use Independently Correlates With Complications After Posterior Lumbar Spine Surgery

Interpretable Machine Learning Models Based on Shapley Additive Explanations for Predicting the Risk of Cerebrospinal Fluid Leakage in Lumbar Fusion Surgery

STUDY DESIGN

Retrospective study.

OBJECTIVES

The objective of this investigation was to formulate and internally verify a customized machine learning (ML) framework for forecasting cerebrospinal fluid leakage (CSFL) in lumbar fusion surgery. This was accomplished by integrating imaging parameters and using the SHapley Additive exPlanation (SHAP) technique to elucidate the interpretability of the model.

SUMMARY OF BACKGROUND DATA

Given the increasing incidence and surgical volume of spinal degeneration worldwide, accurate predictions of postoperative complications are urgently needed. SHAP-based interpretable ML models have not been used for CSFL risk factor analysis in lumbar fusion surgery.

METHODS

Clinical and imaging data were retrospectively collected from 3505 patients who underwent lumbar fusion surgery. Six distinct machine learning models were formulated: extreme gradient boosting (XGBoost), decision tree (DT), random forest (RF), support vector machine (SVM), Gaussian naive Bayes (GaussianNB), and K-nearest neighbors (KNN) models. Evaluation of model performance on the test dataset was performed using performance metrics, and the analysis was executed through the SHAP framework.

RESULTS

CSFL was detected in 95 (2.71%) of 3505 patients. Notably, the XGBoost model exhibited outstanding accuracy in forecasting CSFLs, with high precision (0.9815), recall (0.6667), accuracy (0.8182), F1 score (0.7347), and AUC (0.7343). In addition, through SHAP analysis, significant predictors of CSFL were identified, including ligamentum flavum thickness, zygapophysial joint degeneration grade, central spinal stenosis grade, decompression segment count, decompression mode, intervertebral height difference, Cobb angle, intervertebral height index difference, operation mode, lumbar segment lordosis angle difference, Meyerding grade of lumbar spondylolisthesis, and revision surgery.

CONCLUSIONS

The combination of the XGBoost model with the SHAP is an effective tool for predicting the risk of CSFL during lumbar fusion surgery. Its implementation could aid clinicians in making informed decisions, potentially enhancing patient outcomes and lowering healthcare expenses. This study advocates for the adoption of this approach in clinical settings to enhance the evaluation of CSFL risk among patients undergoing lumbar fusion.

Effects of Preoperative Glucocorticoid Use on Patients Undergoing Single-Level Lumbar Fusions: A Retrospective Propensity Score-Matched Registry Study

Objective Spinal fusions are gaining popularity as a means of treating spinal deformity and instability from a range of pathologies. The prevalence of glucocorticoid use has also increased in recent decades, and their systemic effects are well-documented. Although commonly used in the preoperative period, the effects of steroids on outcomes among patients undergoing spinal fusions are inadequately described. This study compares the odds of developing complications among patients who underwent single-level lumbar fusions with and without preoperative glucocorticoid use in hopes of establishing more evidence-based parameters for guiding preoperative steroid use. Methods The TriNetX multi-institutional electronic health record database was used to perform a retrospective, propensity score-matched analysis of clinical outcomes of two cohorts of patients who underwent posterior or posterolateral single-level lumbar fusions with and without interbody fusion, those who used glucocorticoids for at least one week within a year of fusion and those who did not. The outcomes of interest were examined within 30 days of the operation and included death, reoperation, deep or superficial surgical site infection (SSI), pneumonia, reintubation, ventilator dependence, tracheostomy, acute kidney injury (AKI), renal insufficiency, pulmonary embolism (PE) or deep venous thrombosis (DVT), urinary tract infection (UTI), emergency department (ED) visit, sepsis, and myocardial infarction (MI). Results The odds of developing pneumonia within 30 days of spinal fusion in the cohort that used glucocorticoids within one year of operation compared to the cohort without glucocorticoid use was 0.67 (p≤0.001, 95% CI: 0.59-0.69). The odds of requiring a tracheostomy within 30 days of spinal fusion in the cohort that used glucocorticoids within one year of operation compared to the cohort without glucocorticoid use was 0.39 (p≤0.001, 95% CI: 0.26-0.60). The odds of reoperation, deep and superficial SSI, and ED visits within 30 days of operation were significantly higher for the same glucocorticoid-receiving cohort, with odds ratios of 1.4 (p=0.003, 95% CI: 1.11-1.65), 1.86 (p≤0.001, 95% CI: 1.31-2.63), 2.28 (p≤0.001, 95% CI: 1.57-3.31), and 1.25 (p≤0.001, 95% CI: 1.17-1.33), respectively. After propensity score-matching, there was no significant difference between the odds of death, DVT, PE, MI, UTI, AKI, sepsis, reintubation, and ventilator dependence between the two cohorts. Conclusion In support of much of the current literature regarding preoperative glucocorticoid use and rates of complications, patients who underwent a single-level lumbar fusion and have used glucocorticoids for at least a week within a year of operation experienced significantly higher odds of reoperation, deep and superficial SSI, and ED visits. However, these patients using glucocorticoids were also found to have lower odds of developing pneumonia, renal insufficiency, and tracheostomy requirement than those who did not use steroids within a year of surgery.

Early Outcomes of Muscle Flap Closures in Posterior Thoracolumbar Fusions: A Propensity-Matched Cohort Analysis

BACKGROUND

Plastic surgery closure with muscle flaps after complex spinal reconstruction has become increasingly common. Existing evidence for this practice consists of small, uncontrolled, single-center cohort studies. We aimed to compare 30-day postoperative wound-related complication rates between flap closure and traditional closure after posterior thoracolumbar fusions (PTLFs) for non-infectious, non-oncologic pathologies using a national database.

METHODS

We performed a propensity-matched analysis using the 2012-2020 National Surgical Quality Improvement Program dataset to compare 30-day outcomes between PTLFs with flap closure versus traditional closure.

RESULTS

A total of 100,799 PTLFs met our inclusion criteria. The use of flap closure with PTLF remained low but more than doubled from 2012 to 2020 (0.38% vs. 0.97%; P = 0.002). A higher proportion of flap closures had higher American Society of Anesthesiologists classifications and higher number of operated spine levels (all P < 0.001). We included 1907 PTLFs (630 for flap closure; 1257 for traditional closure) in the propensity-matched cohort. Unadjusted 30-day wound complication rates were 1.7% for flap and 2.1% for traditional closure (P = 0.76). After adjusting for operative time, wound complication, readmission, reoperation, mortality, and non-wound complication were not associated flap use (all P > 0.05).

CONCLUSIONS

Plastic surgery closure was performed in patients with a higher comorbidity burden, suggesting consultation in sicker patients. Although higher rates of wound and non-wound complications were expected for the flap cohort, our propensity-matched cohort analysis of flap closure in PTLFs resulted in non-inferior odds of wound complications compared to traditional closure. Further study is needed to assess long-term complications in prophylactic flap closure in complex spine surgeries.

Effects of Preoperative Chronic Steroid Use on Postoperative Outcomes in Orthopedic Surgery: A Systematic Review and Meta-Analysis

Higher rates of postoperative complications have been found in preoperative chronic steroid users. However, the effects of preoperative chronic steroid use on outcomes in orthopedic surgery were unclear. We performed a systematic review of cohort studies examining the effects of chronic steroid use on postoperative outcomes following orthopedic surgery and searched PubMed, Embase, and CENTRAL through 29 April 2023. We included 17 studies with 1,546,562 patients. No increase in 30-day mortality (adjusted odds ratio (aOR) 1.40, 95% confidence interval (CI) 0.64-3.09) and composite thromboembolic events (aOR 1.61, 95% CI 0.99-2.63) but increases in 30-day overall complications (aOR 1.42, 95% CI 1.16-1.75), wound dehiscence (aOR 2.91, 95% CI 1.49-5.66), infectious complications (any infection (aOR 1.61, 95% CI 1.44-1.80), sepsis (aOR 2.07, 95% CI 1.34-3.21), superficial surgical site infection (SSI) (aOR 1.73, 95% CI 1.03-2.89) and deep SSI (aOR 1.96, 95% CI 1.26-3.05)), re-admission (aOR 1.62, 95% CI 1.48-1.77), both 30-day (aOR 1.28, 95% CI 1.03-1.59) and 1-year re-operation (aOR 1.78, 95% CI 1.09-2.92), pulmonary embolism (aOR 5.94, 95% CI 1.52-23.29), and deep vein thrombosis (aOR 2.07, 95% CI 1.24-3.46) were detected in preoperative steroid users. An increased risk of adverse outcomes following orthopedic surgery in chronic steroid users was found.

Risks of Immunosuppressive Therapy in Patients Undergoing Open Reduction Internal Fixation for Ankle Fractures

Chronic steroid and immunosuppressant use have been shown to increase the risk for postoperative complications in orthopedic surgery. Further understanding of the risks of immunosuppression is necessary to aid in risk stratification and patient counseling. However, these risks have not yet been explored in ankle fracture patients. Thus, the purpose of this study is to determine whether patients taking immunosuppressives are at an increased risk for morbidity and mortality following open reduction and internal fixation (ORIF) of ankle fractures. Patients undergoing operative treatment for ankle fractures from 2006 to 2018 were identified in the National Surgical Quality Improvement Program database. Patients were categorized based on their use of immunosuppressive medications. Postoperative outcomes assessed included superficial surgical site infections, deep surgical site infections, organ space infections, wound dehiscence, pneumonia, unplanned intubation, pulmonary embolism, urinary tract infection, renal failure, blood transfusion requirement, deep vein thrombosis, sepsis, cardiac arrest, extended length of hospital stay, readmission, reoperation, and mortality. Univariate and multivariate analyses were performed. In total, 10,331 patients underwent operative treatment for ankle fracture. Total 10,153 patients (98.3%) were not taking immunosuppressants and 178 (1.7%) were taking these medications. In multivariate analysis, patients taking immunosuppressants were at increased risk of pulmonary embolism (odds ratio [OR] 4.382; p = .041) and hospital readmission (OR 2.131; p = .021). Use of immunosuppressive medications is an independent risk factor for pulmonary embolism and readmission following ORIF for ankle fractures. Notably, no association with wound complications, infections, or sepsis was identified.