Outcome of Internal Neurolysis for Trigeminal Neuralgia without Neurovascular Compression and Its Relationship with Intraoperative Trigeminocardiac Reflex

Abstract

Background: Internal neurolysis (IN) is an effective surgical treatment for trigeminal neuralgia (TN) without neurovascular compression (NVC) or postoperative recurrence. However, the trigeminal nerve is directly manipulated during the procedure, and there is a high incidence of trigeminocardiac reflex (TCR). The aim of this study was to retrospectively analyze the outcome of IN and to explore its relationship with the occurrence of intraoperative TCR.

Methods: Surgical and anesthesia records of 27 TN patients who underwent surgical treatment with IN at our department between March 2010 and September 2016 were retrospectively analyzed. Patients were divided into 2 groups on the basis of the occurrence of TCR during surgery, and clinical characteristics were compared. Pain intensity was assessed by the Barrow Neurological Institute (BNI) pain intensity score and BNI facial numbness score.

Results: TCR was observed in 23 of 27 patients (85.2%); it manifested as obvious changes in mean arterial pressure and heart rate by at least 20% of the baseline values. Trigeminal nerve atrophy was found in 9 patients (33.3%). The immediate pain-free rate was 96.3%, and the "excellent" rate was 72.1% for follow-up, with a rate of numbness or hypesthesia of 97.1%. These outcomes were retrospectively compared between the TCR and non-TCR groups, and there was a nonsignificantly higher "excellent" rate in the TCR group than in the non-TCR group.

Conclusions: This study demonstrated that IN is an effective treatment for TN without NVC and has a close relationship with intraoperative TCR. To our knowledge, this is the first research describing TCR during IN.

Keywords: Internal neurolysis; Trigeminal neuralgia; Trigeminocardiac reflex.