Clinical Effectiveness of Peripheral Nerve Blocks for Diagnosis of Migraine Trigger Points.

Background: With a 13 percent global prevalence, migraine headaches are the most commonly diagnosed neurologic disorder, and are a top five cause of visits to the emergency room. Surgical techniques, such as decompression and/or ablation of neurovasculature, have shown to provide relief. Popular diagnostic modalities to identify trigger loci include handheld Doppler examinations and botulinum toxin injection. This article aims to establish the positive predictive value of peripheral nerve blocks for identifying therapeutic surgical targets for migraine headache surgery.

Methods: Electronic medical records of 36 patients were analyzed retrospectively. Patients underwent peripheral nerve blocks using 1% lidocaine with epinephrine and subsequent surgery on identified migraine headache trigger sites. Patients were grouped into successful and unsuccessful blocks and further categorized into successful and unsuccessful surgery subgroups. Group analysis was performed using paired t tests, and positive-predictive value calculations were performed on subgroups.

Results: The preoperative Migraine Headache Index of patients with positive blocks was 152.71, versus 34.26 postoperatively (p < 0.001). Each index component also decreased significantly: frequency (22.11 versus 15.06 migraine headaches per month; p < 0.001), intensity (7.43 versus 4.12; p < 0.001), and duration (0.93 versus 0.55 days; p < 0.001). The positive-predictive value of diagnostic peripheral nerve blocks in identifying a migraine headache trigger site responsive to surgical intervention was calculated to be 0.89 (95 percent CI, 1 to 0.74).

Conclusions: To the authors' knowledge, this is the first study to investigate the positive-predictive value of peripheral nerve blocks as used in the diagnostic workup of patients with chronic migraine headaches. Peripheral nerve blocks serve as a reliable clinical tool in mapping migraine trigger sites for surgical intervention while offering more flexibility in their administration and recording as compared to established diagnostic methods. .

Clinical Question/level Of Evidence: Diagnostic, IV.