Long-Term Results of Gamma Knife Radiosurgery for Trigeminal Neuralgia

Objective: Although the short- to medium-term efficacy of Gamma Knife therapy for drug-resistant essential trigeminal neuralgia has been reported, long-term evaluations are limited. We evaluated patient data obtained at least 10 years post-treatment and examined the significance of this treatment using new end points.

Methods: Among 249 consecutive patients with essential trigeminal neuralgia who were treated with Gamma Knife radiosurgery (retrogasserian target/4-mm single isocenter/90 Gy at 100%) at our institution between January 2003 and October 2011, 103 patients who were followed up for at least 10 years (mean, 174 [120-219] months) after treatment and whose data were amenable to accurate evaluation, were included in this retrospective study. Herein, we used the Barrow Neurological Institute (BNI) pain intensity scale as a clinical evaluation method for pain and the BNI numbness scale to evaluate complications (namely facial dysesthesia).

Results: The initial and final follow-up pain attack cessation (BNI pain intensity score I-IIIa) rate was 82.5% (85 of 103) and 58.2% (60 of 103), respectively. Furthermore, sensory impairment (BNI numbness score ≥ II) at the last follow-up was observed in 24.3% (25 of 103) of the cases, while very bothersome status (BNI numbness score IV) was observed in 2.9% of the cases.

Conclusions: Gamma Knife radiosurgery for essential trigeminal neuralgia showed good therapeutic effects during long-term follow-up. Serious complications of significant concern in the short- to mid-term follow-up, resolved spontaneously. Therefore, the indications for treatment should be expanded to include patients who strongly desire Gamma Knife therapy.