Referral of pain from dural stimulation in man
✓ Electrical stimulation of the dura was carried out in 25 patients using chronically implanted electrodes to determine areas of referred pain. Referred pain occurred over areas supplied by all divisions of the trigeminal nerve and the upper three cervical spinal nerves. No pattern of pain referral could be established on the basis of electrode positions determined from bone landmarks on the skull. It is suggested that these findings may be explained either by a greater overlap of the dural nerves than had been previously recognized, or by an overlap of the connections of the cervical nerves and the trigeminal nerve in the dorsal horn of the cervical spinal cord. Both of these mechanisms seem to be operative to some degree. Bilateral and contralateral pain was also elicited; whether this was due to stimulation of the bilateral termination of the dural nerves near the midline or of the bilateral central projections of these dural nerves is not clear. Contralateral referral of pain from dural points widely separated from the midline, however, suggests that some contralateral central projections do exist. The authors conclude that head pain of dural origin has limited clinical usefulness because of the lack of consistent specificity in its referral pattern.