The Scratch Collapse Test for Diagnosis and Treatment of Trigger Sites for Migraine Surgery.

Diagnosis of trigger sites for migraine surgery relies on history to detect a constellation of symptoms and secondarily, nerve blocks, imaging studies, and Doppler probe examination. The scratch collapse test (SCT) has been described for localization of compressive neuropathies in the upper and lower extremities. In this study, we hypothesized that the SCT could also be used to diagnose trigger sites for surgical planning in migraine surgery. Eleven consecutive patients presenting for migraine surgery, and four patients presenting with recurrent headaches and secondary trigger sites after initial successful migraine surgery were examined with the SCT using a standard protocol to assess involvement of bilateral sites I, II, IV, V, and VI, with the carpal tunnel as a negative control. The SCT was positive bilaterally at sites I, II, IV, V, and VI for all patients presenting primarily for migraine surgery, regardless of trigger sites localized by history and other secondary modalities. The SCT, however, correlated with secondary trigger sites localized through history and examination for patients presenting with recurrent migraine headaches after previous primary surgery. The SCT is not reliable for localization of trigger sites in patients presenting primarily for migraine surgery. This likely relates to central sensitization of migraine headaches, leading to global cutaneous allodynia in the head and neck. In patients with recurrent migraine headaches, abrogation of central sensitization following the initial surgery allows diagnosis of secondary trigger sites through the SCT.