Targeted Peripheral Nerve-Directed Onabotulinumtoxin A Injection is an Effective Long-Term Therapy for Migraine Headache

Background: Onabotulinumtoxin A (Botox) is an FDA-approved treatment for chronic migraine headaches (MH) that involves on-label, high-dose administration across 31 anatomic sites. Anatomically-specific peripheral nerve trigger sites have been identified that contribute to MH pathogenesis and are amenable to both Botox injection and surgical decompression. These sites do not always correlate with the on-label FDA-approved injection pattern, but represent a more targeted approach. The efficacy of anatomically-directed trigger site Botox injection, as an independent long-term therapeutic option, has not been investigated.

Methods: A retrospective review was completed for 232 patients with MH. Sixty-six patients elected to proceed with diagnostic Botox injections. Of these, 24 continued long-term therapeutic Botox injections while 42 matriculated to surgery. Outcomes were tracked.

Results: Therapeutic long-term trigger site-directed Botox injection resulted in significant improvement in migraine headache index (MHI) (53.5+/-83.0, p<0.006), headache days/month (9.2+/-12.7, p<0.0009) and migraine severity (2.6+/-2.5, p<0.00008) versus baseline. MHI improved from the initiation of diagnostic injections to the establishment of steady-state injections (p<0.002), and further improved over time (p<0.05, mean follow-up 615 days) with no desensitization observed. Decompressive surgery resulted in significant improvement in MHI (100.8+/-109.7, p<0.0000005), headache days/month (10.8+/-12.7, p<0.000002), migraine severity (3.0 +/- 3.8, p<0.00001), and migraine duration in hours (16.8+/-21.6, p<0.0007). MHI improvement with surgery was better than long-term Botox injection (p<0.05).

Conclusions: Though inferior to surgical decompression, anatomically-directed therapeutic trigger site Botox injection is an effective therapy for MH as an alternative to non-site-directed Botox injection with decreased dosage requirements and the potential for decreased cost.