Objective The aim of the present study was to describe and evaluate the initial and the long-term clinical outcome of internal neurolysis (IN) for trigeminal neuralgia (TN) without neurovascular compression (NVC). Methods A total of 170 patients diagnosed with TN were treated by posterior fossa exploration, during the period between April 2012 and October 2019.

The patients were divided into two groups:

Group A (50 patients)was treated by IN and Group B (120 patients) received microvascular decompression (MVD). Surgical outcomes and postoperative complications were compared between the two groups. Pain intensity was assessed by the Barrow Neurological Institute (BNI) pain intensity score and BNI facial numbness score. Pain recurrence was statistically evaluated with Kaplan-Meier analysis. Results Pain was completely relieved in 44 patients (88%) who underwent IN (group A); 3 (6%) experienced occasional pain but did not require medication (BNI 2). In group B, 113 (94%) experienced immediate pain relief after MVD. The median duration of follow-ups was 4 years (6 months to 7.5 years). In Group A, there was a meantime recurrence of 27 months in 3 patients (6%). The recurrence in Group B was of 5.8% during the follow-up period. There were no statistically significant differences in the surgical outcomes between the two groups. All patients with IN experienced some degree of numbness, 88% of the cases resolved in 6 months, on average. Conclusion Internal neurolysis is an effective, safe and durable treatment option for trigeminal neuralgia when NVC is absent.