Microvascular decompression for trigeminal neuralgia in patients with and without prior stereotactic radiosurgery

Radiosurgery has emerged as an important primary treatment means of typical trigeminal neuralgia. Despite its high safety and efficacy, the likelihood of recurrence is significant, potentially requiring salvage treatment. Posterior fossa exploration and microvascular decompression is an option for salvage treatment. Results are presented regarding a single-surgeon experience, and a grading scale is proposed for postirradiation surgical findings.

A retrospective analysis of the author's experience with 109 consecutive posterior fossa explorations for typical trigeminal neuralgia performed over a period of 8 years is included in this analysis. There were 42 patients undergoing microvascular decompression following recurrence of pain after radiosurgery, and 67 patients underwent microvascular decompression without prior radiosurgery. Operative findings were reviewed and categorized. A 4-category typing system is proposed. The Barrow Neurological Institute Pain Scale Score was used to categorize post-microvascular decompression outcomes.

Within the postradiosurgery group, 41 of 42 patients had initial treatment success (Barrow Neurological Institute score 1 to 3), comparing favorably with the nonirradiated group, in which 59 of 67 patients had initial successful treatment (P=0.15, Fisher exact test, 2-tailed). Findings of conflicting vessel atherosclerosis and adhesions between conflicting vessel and nerve were only seen in the postradiosurgery group, whereas arachnoid thickening requiring sharp dissection was seen in both postradiosurgery and nonirradiated groups. Increased difficulty of dissection in either the radiosurgery or the nonirradiated groups did not appear to affect the likelihood of satisfactory outcome.

Microvascular decompression can be performed in the postradiosurgery setting safely with high efficacy. Dissection typically was not significantly more difficult in comparison to procedures performed without prior history of radiosurgery intervention.