The Pivotal Role of Arachnoid-Nerve Conflict in Trigeminal Neuralgia without Neurovascular Conflict.

OBJECTIVE

The etiology of trigeminal neuralgia (TN) without neurovascular conflict (NVC) is unknown, and classic neurovascular decompression procedures are not applicable. We analyzed a potential etiology in patients operated on for TN without NVC.

METHODS

Clinical, radiological, and treatment outcome data were retrospectively reviewed in a consecutive cohort of 37 patients with medically intractable TN without detectable NVC on preoperative 3T magnetic resonance imaging or during surgery. All patients underwent endoscopic-assisted microsurgical trigeminal nerve release from tethering arachnoid between January 2019 and December 2023. Intraoperative findings were compared with findings of a control group of 22 patients undergoing surgery for other pathologies within the cerebellopontine angle.

RESULTS

Median age of 24 women and 13 men with TN was 58 years (interquartile range 48-71 years). Mean preoperative pain intensity scores on the visual analog scale and Barrow Neurological Institute scale were 9.5/10 and V, respectively. Surgical exploration revealed an arachnoid-nerve conflict in all cases of TN (cohort group) and in only 2 patients in the control group (P < 0.001). Release of the trigeminal nerve from its anchoring arachnoid yielded significant postoperative improvement of visual analog scale score (1.6/10, P < 0.001), and 84% of patients with TN became pain-free and medication-free (Barrow Neurological Institute score I) after a median postoperative follow-up of 24 months (interquartile range 7-46 months).

CONCLUSIONS

Arachnoid-nerve conflict seems to play a pivotal role in the etiology of TN without NVC. Trigeminal nerve release from tethering arachnoid effectively achieves pain relief and medication independence.