Effects of the length of preoperative conservative management on postoperative outcomes after primary microvascular decompression for trigeminal neuralgia

OBJECTIVE Although trigeminal neuralgia (TN) is initially managed conservatively, approximately half of all patients will eventually undergo surgery. Despite this outcome, there is limited understanding of the relationship between preoperative length of conservative management and pain outcomes after microvascular decompression (MVD). In this study, the authors aimed to describe the relationship between the duration of preoperative conservative management and postoperative outcomes in patients undergoing MVD for TN. METHODS The electronic medical records of 381 patients with TN who underwent primary MVD at the authors’ institution between 2007 and 2023 were reviewed. Patients were dichotomized based on whether the duration of conservative management, defined as the duration of anticonvulsant use, was greater than, or less than or equal to, the median duration of conservative management for the entire cohort. For adjusted analysis, duration of conservative management was also assessed as a continuous variable. Demographic information, comorbidities, clinical TN characteristics, pain recurrence, and pre- and postoperative modified Barrow Neurological Institute (BNI) pain and numbness scale scores were recorded and compared between groups. Differences in pain outcomes were assessed via multivariate ordinal regression, Kaplan-Meier analysis, and Cox proportional hazards analysis. RESULTS The median preoperative duration of conservative management was 1.74 years. Patients with a prolonged duration of conservative management were significantly more likely to be male (p = 0.028) and less likely to preoperatively use opioids (p = 0.037). At final follow-up, those with a prolonged duration of conservative management had significantly higher reported BNI pain scores (p = 0.021) and higher rates of pain recurrence (p = 0.021). On multivariable ordinal regression analysis, younger age (p < 0.001) and prolonged duration of conservative management, which was assessed as both a dichotomized (p = 0.002) and continuous variable (p = 0.011), were associated with higher BNI pain scores at final follow-up. Patients with a longer duration of conservative management also had a significantly shorter time to pain recurrence, as assessed by Kaplan-Meier survival analysis (p = 0.0037) as well as Cox proportional hazards analysis (p = 0.001, dichotomized; p = 0.008, continuous). CONCLUSIONS In the setting of primary MVD for patients with TN, a longer duration of preoperative conservative management was associated with higher postoperative BNI pain scores and increased risk of pain recurrence. These findings suggest a potential beneficial role for early surgical intervention.