Onabotulinumtoxin A (BOTOX) is known to be an FDA-approved therapy for chronic migraine headaches (MHs) that comprises high-dose administration over 31 anatomic sites.

Anatomically precise peripheral nerve trigger sites have been recognized that contribute to the pathogenesis of MH and are responsive to both BOTOX injection and surgical decompression. These sites do not continually connect with the on-label FDA-approved injection pattern but signify a more focused approach. There is lack of evidence demonstrating the effectiveness of peripheral nerve–directed BOTOX injection as an independent long-term therapeutic option.

Lately, a group of investigators described the technique for peripheral nerve–directed therapeutic long-term BOTOX injection. A retrospective review was done involving 223 patients with MH. A total of 66 patients were selected to continue with diagnostic BOTOX injections. Out of these 64, 24 continued long-term therapeutic BOTOX injections, whereas 42 enrolled in surgery. Tracking of outcomes was done.

The prime outcomes involved showed notable 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) compared to baseline. The improvement was also noticed in MHI from the initiation of diagnostic injections to the establishment of steady-state injections (P < 0.002). It further improved over time (P < 0.05, mean follow-up 615 days) with no desensitization. Decompressive surgery produced meaningful 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 found to be better than long-term BOTOX injections (P < 0.05)

Although targeted peripheral nerve–directed BOTOX injection was found to be inferior to surgical decompression, preliminary data confirmed it to be an effective primary therapy for MH.  It may act as a possible alternative to non-directed BOTOX injection with decreased dosage needs and probably reduced cost.