Background: Trigeminal neuralgic pain most commonly occurs after neurovascular conflict and can be treated by microvascular decompression [MVD].

Objective: To discuss the effectiveness of keyhole retromastoid retrosigmoid MVD for pain control both in the short- and long-term.

Materials and Methods: Between 2007 and 2016, 444 patients affected by trigeminal neuralgia [TN] underwent keyhole retromastoid retrosigmoid MVD. All patients had already tried conservative treatment using a variety of medications without effective benefit. Clinical presentation, preoperative imaging results, operative findings (causes of compression), pain outcomes, and recurrence rates were reviewed.

Results: In the early phase, the first keyhole MVD provided excellent outcomes in terms of achieving immediate pain control (436 of 444 patients, 98.19%, p = 0.000), while the second (re-) MVD of this group achieved favorable outcomes in only 66.66% of cases (p = 0.059). In the long-term group, 89.59% (198 of 221 patients) still reported complete pain remission, but the re-MVD for this group resulted in pain relief for only 38.46% of cases (p = 0.405). The number of serious complications found in the present series was very low.

Conclusion: Keyhole MVD is an effective and reliable method of pain relief after TN both in the short- and long-term. Re-MVD in both groups attained less favorable outcomes, but the differences were not statistically significant. Thorough intraoperative exploration of the dorsal root entry zone [DREZ], and meticulous dissection by neurosurgeons are both mandatory to achieve pain relief and reduce the incidence of complications after MVD.

Keywords: Trigeminal neuralgia, Microvascular decompression, Keyhole