OnabotulinumtoxinA injections in chronic migraine, targeted to sites of pericranial myofascial pain: an observational, open label, real-life cohort study

Abstract

Background: OnabotulinumtoxinA has proven its efficacy in reducing the number of headache days in chronic migraine (CM) patients. The usual paradigm includes 31 pericranial injection sites with low dose (5 U) per site. The aim of this study is to present the results obtained using a simpler injection protocol of onabotulinumtoxinA, with injection sites targeted to pericranial myofascial sites of pain.

Methods: Observational, open label, real-life, cohort study. We enrolled 63 consecutive patients fulfilling the diagnostic criteria of CM, and refractory to conventional treatments. The patients were injected using a "follow-the-pain" pattern into the corrugator and/or temporalis and/or trapezius muscles. The doses per muscle were fixed. According to the number of muscles injected, the total dose could vary from 70 to 150 U per session. Patients were considered responders if they had a ≥ 50% decrease in number of headache days in at least two consecutive injection cycles.

Results: Forty one patients (65.1% in intention to treat analysis) responded to treatment. In 70.7% of responders, the effect size was even higher, with a reduction ≥70% in the number of headache days. The associated cervical pain and muscle tenderness, present in 33 patients, was reduced by ≥50% in 31 patients (94%). Triptan consumption dramatically decreased (81%) in responders. The trapezius was the most frequently injected muscle. We observed no serious adverse event. The mean patient satisfaction rate was 8.5/10.

Conclusions: This study provides additional robust evidence supporting the efficacy of onabotulinumtoxinA injections in CM. Furthermore, the paradigm we used, with reduced number of injection sites targeted to pericranial myofascial sites of pain, may provide evidence in favor of the implication of myofascial trigger points in migraine chronicization.

Trial registration: ClinicalTrials.gov Protocol Record I17022 ClinicalTrials.gov Identifier: NCT03175263 . Date of registration: June 7, 2017. Retrospectively registered.

Conflict of interest statement

Competing interests

Danièle Ranoux received honoraria consultancy from Allergan, travel support and educational grants from Allergan, Merz and Ipsen. The other authors have no competing interests to declare. Publication fees for this manuscript are supported by the Teaching Hospital of Limoges, France.

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Figures

Fig. 1

Flow-chart. During a first phase, called adaptation period, we used a follow-the-pain approach in order to determine the optimal injection scheme for each individual. Once the best procedure was determined for each patient, it was reproduced at each subsequent injection session. This adaptation phase could necessitate up to three sessions. The observation period started 8 weeks before the first efficacious injection and ended 2 months after the second consecutive efficacious injection, or in case of inefficacy. Throughout the adaptation and the observation phases, patients kept a headache diary where they were asked to note the days with headache and the use of rescue medication. The extension period included all treatment cycles after the observation phase. During this period, the injector was allowed to modify the dosage and sites of injections