Pain Maps from Facial Pain Patients Indicate a Broad Pain Geography

Abstract

Two hundred consecutive female patients, who were referred to a university-based facial pain clinic, were asked to mark all painful sites on sketches showing the contours of a human body in the frontal and rear views. The drawings were analyzed with transparent templates containing 1875 (frontal view) and 1929 (rear view) square cells of equal size. The average patient scored 71.8 cells in the frontal and 99.7 cells in the rear view (corresponding to 3.8% and 5.2% of the maximum possible scores). In individual patient drawings, however, up to 42.7% and 44.9% of all cells were marked. Only 37 cases (18.5%) exhibited pain that was limited to the trigeminal system. An analysis of the pain distribution according to the arrangements of dermatomes revealed three distinct clusters of patients: (1) pain restricted to the region innervated by the trigeminal nerves (n = 37); (2) pain in the trigeminal dermatomes and any combination involving the spinal dermatomes C2, C3, and C4, but no other dermatomes (n = 32); and (3) pain sites involving dermatomes in addition to the ones listed above (n = 131). Mean ages in the three clusters were 38.7, 35.5, and 37.5 years, respectively (p = 0.62, n.s.). Widespread pain existed for longer durations (median, 48 months) than conditions involving local and regional pain (median, 24 months) (p = 0.02, s.). Our findings showed that among a great percentage of persistent facial pain patients the pain distribution is more widespread than commonly assumed, and that the persistence of pain in the regional and widespread pain presentations is significantly greater than in cases with pain limited to the trigeminal system.