Use of botulinum toxin A for drug-refractory trigeminal neuralgia: preliminary report

Botulinum toxin type A (BTX-A) has been used to treat migraine and occipital neuralgia. We report preliminary results of an ongoing study that assesses the efficacy of BTX-A on trigeminal neuralgia (TN) patients refractory to medical treatment.We treated 15 patients (8 men and 7 women) between 28 and 67 years of age who were suffering from drug-refractory TN from February 2008 to January 2010. Symptoms, including pain duration, provoking factors, affected nerve branch, frequency of TN attacks, and severity of pain just before injections, were evaluated 1 week, 1 month, and 6 months after injection. We injected 50 U reconstituted BTX-A solution at the trigger zones. The overall response to treatment was assessed via a 9-point patient global assessment scale and compared with values at baseline. Statistical analysis was performed by the analysis of variance (ANOVA) test for frequency of TN attacks, the Friedman test for severity of pain, and the Wilcoxon signed-rank test for PGA, and all with the use of SPSS software.Eight men and 7 women aged 28-67 years (mean 48.9 y) suffering from TN from 6 months to 24 years all improved regarding frequency and severity of pain attacks; in 7 patients, pain was completely eradicated and there was no need for further medication. In 5 patients, nonsteroidal antiinflammatory drugs were enough to alleviate pain attacks, and 3 patients again responded to anticonvulsive drugs after injection. All patients developed higher pain thresholds after injections. The ANOVA test showed a significant difference in frequency of attacks before injection and at 1 week, 1 month, and 6 months after injection (P.001). Friedman test and pair comparison of pain severity scores with Bonferroni correction adjustment showed a significant difference (P.001) between severity of pain before and after injection. Wilcoxon signed-rank test showed significant improvement in all patients up to 6 months after injection (P.001). Complications included transient paresis of the buccal branch of the facial nerve in 3 patients.This study supports other similar studies and shows that BTX-A is a minimally invasive method that can play a role in treating TN before other more invasive therapies, i.e., radiofrequency and surgery.