Repeated radiosurgery for recurrent or refractory trigeminal neuralgia: a systematic review and meta-analysis

Stereotactic Radiosurgery (SRS) is a well-established component of the multimodal approach to treating trigeminal neuralgia (TN), a condition marked by frequent and recurrent episodes despite treatments. As a result, an increasing number of centers are offering patients a second or even third round of SRS. Despite this trend, there remains ongoing debate regarding optimal radiation dosing, target planning, overall treatment efficacy, duration of symptom relief, and the safety of repeated procedures. In this study, we present a systematic review and meta-analysis of the existing literature on repeated stereotactic radiosurgery for patients with refractory and recurrent TN. According to PRISMA guidelines, we extracted data regarding general patients features, pre-radiosurgical treatments, irradiation doses of Radiosurgical cycles, target planning, outcome and complications. Out of 461 patients included, 317 (73%) achieved a Barrow Neurological Institute pain scale (BNI) ≤ III after a second SRS procedure. The mean irradiation dose employed in the second treatment was 68.4 Gy with a cumulative dose of 145.9 Gy. Out of the 317 patients with favourable outcome, 101 (31.9%) relapsed after a mean 19.2 months. Patients who responded to a first SRS course were 6 times more likely to achieve pain control after repeateded SRS. Complications were mild and were mainly represented by V cranial nerve dysfunction in 202 patients (43.8%). No cases of radionecrosis, hydrocephalus, or brainstem damage were reported. With a mean follow-up of 19.2 months, repeat SRS was effective in controlling pain in roughly 47% of patients. Dosimetric analysis showed high variability of irradiation doses and target planning. Although data support the safety of repeated SRS in patients with refractory or recurrent TN, homogeneous treatment protocols and uniformity in data reporting is needed to optimize the potential of repeated SRS.