PURPOSE: Patient selection for migraine surgery is the most important variable to ensure successful outcomes. From verbal and written descriptions alone, it can be difficult to understand patients pain/trigger patterns. In our experience, a superior method to visualize pain is to ask patients to draw where the pain originates and where it radiates. We have found that there are pathognomonic pain patterns for all trigger sites that should be considered in patient selection. We typically do not operate on patients with atypical pain diagrams, as we believe they are poor candidates for surgery. There is a small subset of these atypical patients who undergo surgery based on other strong clinical findings. In this study, we attempt to quantify this clinical experience.
METHODS AND MATERIALS: One-hundred six patients were prospectively enrolled in this study and asked to complete pain diagrams at screening. Diagrams were analyzed and categorized by 2 independent, blinded reviewers: (1) typical—pain over the distribution of a nerve with expected radiation; (2) intermediate—pain over the distribution of the nerve with atypical radiation; and (3) atypical—pain outside of normal nerve distribution and atypical radiation. Surgical outcomes were documented using pre and postoperative migraine headache index (MHI) calculation. MHI between subcategories was compared using unpaired t tests.
RESULTS: MHI improvement was on average 73% ± 38% in the typical, 78% ± 30% in the intermediate, and 30% ± 40% in the atypical pain drawing group. Mean follow-up was 14.1 months. Inter-rater reliability was 94.3% with κ of 0.8984. There was no significant difference in MHI between the typical and intermediate groups. However, there was a significant difference in MHI between the typical and atypical (P = 0.03) and the intermediate and atypical groups (P ≤ 0.01). The chance of achieving MHI improvement >30% in the atypical group was only 20%. A subgroup analysis of atypical pain drawings was performed to establish criteria for classification as atypical: (1) facial pain that is drawn in other areas than the frontotemporal trigger site distribution (ie, drawn at cheek, jaw, chin, anterior neck); (2) pain that starts at a location that does not correspond to a known trigger site; and (3) diffuse pain that is not localized to a trigger site.
CONCLUSION: This study suggests that surgical outcomes for patients with atypical pain patterns are significantly inferior when compared to normal or close to normal patterns. As we continue to develop algorithms to screen patients for migraine surgery, patient self-created pain drawings should be considered as an effective, cheap, and easy to interpret tool to determine candidacy for surgery.