To explore the reasons for the recurrence or ineffectiveness of primary trigeminal neuralgia (PTN) after microvascular decompression (MVD), as well as the method and efficacy of re-craniotomy.

The clinical data of 36 patients with recurrent or ineffective PTN after MVD surgery who were treated by the same surgeon in the Department of Neurosurgery of China-Japan Friendship Hospital from August 2020 to February 2022 were retrospectively analyzed. According to intraoperative findings, the causes of recurrence or ineffectiveness were divided into adhesion and compression of trigeminal nerve (type Ⅰ), omission of offending vessels (type Ⅱ), incomplete decompression (type Ⅲ) or misjudgment of offending vessels (type Ⅳ), and " granulomatous" changes caused by implanted materials (type Ⅴ). For different reasons, strategies such as separation of adhesions, MVD surgery, and removal of " granulomatous" mass were adopted. The Barrow Neurological Institute (BNI) pain scale was used to evaluate the efficacy, and postoperative BNI pain score ≤ 2 was defined as an excellent surgical outcome.

All patients successfully underwent the operation. The recurrence or ineffectiveness cause was type Ⅰ in 22 cases (61.1%), type Ⅱ in 7 cases (19.4%), type Ⅲ in 3 cases (8.3%), type Ⅳ in 2 cases (5.6%), and type Ⅴ in 2 cases (5.6%). In this series, 47% (17/36) of patients had varying degrees of facial or ipsilateral anterior tongue numbness after surgery, which gradually eased after 3 to 6 months. The follow-up time of 36 patients was (10.2±3.7) months (3-16 months). To the last follow-up, the postoperative BNI pain score of 36 patients was 1 point in 34 cases, 2 points in 1 case, and 4 points in 1 case (improved to 2 points after balloon compression therapy). There was no case of recurrence. The rate of excellent and good outcomes was 97% (35/36).

For patients with recurrent or ineffective PTN after MVD surgery, the recurrence or ineffectiveness causes can be divided into 5 types according to the intraoperative findings of reoperation. It is safe and effective to use specific surgical methods according to different etiologies.

Trigeminal neuralgia; Recurrence; Clinical protocols; Microvascular decompre-ssion; Cause