Predicting cerebrospinal fluid leakage prior to posterior circumferential decompression for the ossification of the posterior longitudinal ligament in the thoracic spine

Background: Cerebrospinal fluid leakage (CSFL) is one of the most common complications after posterior transarticular osteotomy and circumferential decompression (CD) for the ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine. Predicting CSFL preoperatively would be of great value to surgeons. The aim of this study was to discover the factors that can predict CSFL prior to CD and incorporate them into a predictive model. Methods: Sixty-one patients with OPLL who underwent posterior transarticular osteotomy and CD at Peking University International Hospital were divided into a CSFL group and a non-CSFL group. Univariate analysis was used to identify possible predictors. A multivariate logistic regression model was developed to predict the probability of CSFL. Model validation was performed using a receiver operating characteristic (ROC) curve. Results: CSFL occurred in 31.1% of patients. Univariate regression analysis showed statistical differences (P<0.05) in smoking history, segment of CD, whether OPLL was combined with the ossification of the ligamentum flavum (OLF), number of laminectomies, occupying ratio, and OPLL base ratio. Our multivariate regression model showed that CSFL predictors included smoking history [odds ratio (OR) =30.1; P=0.003], the upper thoracic segment (OR =188.0; P=0.002), the middle thoracic segment (OR =57.4; P=0.005), and the OPLL base ratio (OR = 1.3; P=0.007). The ROC curve was in the upper left corner [area under the curve =0.955, 95% confidence interval (CI): 0.91-1.00; P<0.001], indicating the model had good predictability. Conclusions: The predictive model shows that if patients with thoracic OPLL have a history of smoking, or the segment of CD is in the upper or middle thoracic spine, or the OPLL has a wide base, The possibility for postoperative CSFL occurring is higher. Using these factors, a surgeon can preoperatively warn patients of the probability of CSFL occurring after posterior transarticular osteotomy and CD.