127 A Novel Scoring System for Preoperative Prediction for Pain-Free Survival After Microsurgery for Trigeminal Neuralgia

Abstract

Abstract INTRODUCTION Pain relief following microsurgery for trigeminal neuralgia (TN) may be related to multiple factors including pain type, degree of neurovascular conflict, arterial compression, and location of compression. The objective of this study was to construct a predictive scoring system based on clinical and radiographic factors that can preoperatively prognosticate long-term outcomes in TN following surgery. METHODS 275 patients with Type 1 or Type 2 TN underwent microvascular decompression (MVD) or internal neurolysis (IN) following a preoperative high-resolution MRI. Outcome data was obtained retrospectively by chart review and/or phone follow-up. Characteristics of neurovascular conflict were obtained from preoperative MRI. Factors that resulted in a probability value of <0.05 on univariate logistic regression analyses were entered into a multivariate cox regression analysis in a backward stepwise fashion. For the multivariate analysis, significance at the 0.15 level was used. A prognostic system was then devised with three possible scores (0/1, 2, or 3) and survival analyses were conducted. RESULTS >Univariate predictors of pain-free survival were pain type (P = 0.013), presence of any vessel (P = 0.042), and neurovascular compression severity (0.038). Scores of 0/1, 2, and 3 were found to be significantly different in regard to pain-free survival (log rank, P = 0.008). At 5 and 10 years there were 42, 57, and 72% and 42,52, and 58%, pain free survival in groups 0/1, 2, and 3, respectively. TN1 patients with severe neurovascular conflict (score of 3) had the best outcome, which was significantly better that TN1 patients without neurovascular conflict (score of 1) (log rank, P = 0.005). Severe neurovascular conflict is more likely to have arterial compression (99%) (P< 0.001). CONCLUSION Pain-free survival of TN patients after microsurgery can be predicted in a step-wise statistically significant fashion, by a simple scoring system based on preoperative clinical and radiographic findings.