Repeat Radiosurgery for Trigeminal Neuralgia

Abstract

Background: Repeat Gamma Knife radiosurgery (GKRS) is an established option for patients whose pain has recurred after the initial procedure, with reported success rates varying from 68% to 95%. Predictive factors for response to the repeat GKRS are ill-defined.

Objective: This cohort study aimed to report the outcomes and factors predictive of success for patients who have undergone repeated GKRS for trigeminal neuralgia at Wake Forest University Baptist Medical Center.

Methods: Between 1999 and 2013, 152 patients underwent repeat GKRS at Wake Forest, 125 of whom were available for long-term follow-up. A retrospective chart review and telephone interviews were conducted to determine background medical history, dosimetric data, outcomes, and adverse effects of the procedure.

Results: Eighty-four percent of patients achieved at least Barrow Neurological Institute (BNI) IIIb pain relief, with 46% achieving BNI I. The 1-, 3-, and 5-year rates of BNI I pain relief were 63%, 50%, and 37%, respectively. The 1-, 3-, and 5-year rates of BNI IIIb or better pain relief were 74%, 59%, and 46%, respectively. One patient experienced bothersome numbness and 2 patients developed anesthesia dolorosa. The dominant predictive factors for pain relief were facial numbness after the first GKRS and a positive pain response to the first GKRS.

Conclusion: Repeat GKRS is an effective method of treating recurrent trigeminal neuralgia. Patients who have facial numbness after the first treatment and a positive pain response to the first GKRS are significantly more likely to respond well to the second treatment.

FIGURE 1.

Flow diagram depicting the determination of patient eligibility. GKRS, Gamma Knife radiosurgery.

FIGURE 2.

Time to BNI II to V failure and BNI IV to V following second GKRS. Kaplan-Meier curve for maintenance BNI I and BNI IIIb pain relief after the second GKRS. BNI, Barrow Neurological Institute; GKRS, Gamma Knife radiosurgery.

FIGURE 3.

Time to BNI IV/V failure following second GKRS by IIIb or greater response to initial GKRS. Kaplan-Meier curves for maintenance of at least BNI IIIb pain relief after the second GKRS by pain relief after initial GKRS (BNI I-IIIb vs BNI IV-V). Patients with a good outcome (BNI I-IIIb) after the first GKRS were significantly more likely to have durable pain relief than those who did not respond to the first GKRS (BNI IV-V). BNI, Barrow Neurological Institute; GKRS, Gamma Knife radiosurgery.

FIGURE 4.

Time to BNI IV/V failure following second GKRS by concurrent diagnosis of multiple sclerosis. Kaplan-Meier curves for maintenance of at least BNI IIIb pain relief after the second GKRS depending on a past history of multiple sclerosis. Although those without MS appeared to be more likely to maintain pain relief after the second GKRS on univariate analysis, there was not a significant relationship on multivariate analysis. BNI, Barrow Neurological Institute; GKRS, Gamma Knife radiosurgery; MS, multiple sclerosis.