Single-site botulinum toxin type A injection for elimination of migraine trigger points

Background.-Botulinum toxin may be effective in suppressing migraine. Most injection regimens utilized have involved multiple sites. Purpose.-To evaluate prospectively the effect of botulinum toxin type A injections into the corrugator supercilii muscles alone on the frequency and severity of migraine. Methods.-Twenty- nine patients (24 women, 5 men) with migraine were enrolled in the study. Average age was 45 years (range, 24 to 63). The frequency (number of migraines per month) and intensity (recorded on an analog scale of 1 to 10, 10 being most severe) of headache were recorded before and after treatment. Twenty-five units of botulinum toxin type A was injected into each corrugator supercilii muscle, for a total of 50 units. Results.-At 2 months, 24 (83%) of 29 patients reported a positive response to the injection of botulinum toxin type A (P <.001). Sixteen patients (55%) reported complete elimination of headache (P <.001), 8 (28%) experienced significant improvement (at least 50% reduction in frequency or intensity) (P <.04), and 5 (17%) did not notice a change in headache. The duration of efficacy of the botulinum toxin type A injections ranged from 6 to 12 weeks, with an average of 8 weeks. In patients who had improvement in migraine but not complete elimination, the headache frequency decreased from 6.4 to 2.1 per month on average (P <.04), and the intensity decreased from 8.6 to 6.1 (P <.04). Conclusion.- These results support the hypothesis that focal injection of botulinum toxin type A may be an effective therapy for migraine.