Stereotactic Radiosurgery for Trigeminal Neuralgia in Patients with Multiple Sclerosis: A Multicenter Study

Abstract

Facial pain response to various surgical interventions in patients with multiple sclerosis (MS)-related trigeminal neuralgia (TN) is considered much less favorable than for typical TN. No large patient series has been published regarding stereotactic radiosurgery (SRS), the least invasive treatment modality for MS patients with medically refractory TN. This is a multicenter retrospective study investigating the clinical outcomes following SRS for patients with MS-related TN. A total of 263 patients contributed by nine member institutions of the International Gamma Knife Research Consortium (IGKRF) constituted this study. The median age at the time of SRS was 57 years (range, 31 to 90 years). Eighty-seven patients (33%) had undergone various surgical procedures prior to SRS. The median latency period of pain response after SRS was one month (range, 1 day to 14.1 months). Reasonable pain control (BNI Pain Scores I-IIIb) was achieved in 232 patients (88.2%). The median maintenance period from SRS was 14.1 months (range, 10 days to 10 years). The actuarial reasonable pain control maintenance rate at 1 year, 2 years, and 4 years was 54%, 35%, and 24%, respectively. There was a statistically significant correlation between the status of achieving BNI-I and the maintenance of facial pain recurrence-free rate. The median recurrence-free rate was 36 months and 12.2 months in patients achieving BNI-I and those of BNI greater than I, respectively (log rank test, P = 0.046). A negative correlation between the time interval from the last initiation of MS exacerbation to the first SRS and possibility of reaching BNI-I was identified (P = 0.002, OR = 1.99, 95% CI, 1.30 to 3.12). Among 210 patients with known status of post-SRS complications, the new-onset of facial numbness (BNI-I or II) after SRS occurred in 21 patients (10%). In the largest series investigating the efficacy and safety of MS-related TN treated SRS, this approach offers a reasonable benefit to risk profile for patients who have exhausted medical management. More favorable initial response to SRS may predict a long-lasting pain control. Earlier treatment with SRS in the presence of MS relapse may lead to an increasing rate of achieving BNI-I facial pain relief.