Patient Position: Supine.

Indications: Trigeminal neuralgia (“tic douloureux”), cluster headache, ocular pain, cancer pain, surgical anesthesia, differential neural blockade, prognostic block for neurolytic procedures.

Needle Size: 16-gauge, 32-mm angiocatheter (introducer), 20-gauge curved, blunt Racz-Finch Kit (RFK needle; Radionics, Burlington, MA) is preferred or 22-gauge b-beveled needle, 3-mL syringe, T-connector tubing.

Medications: 0.2% ropivacaine and 2% lidocaine in a 1:1 mixture for block (0.25% bupivacaine or 0.25% levobupivacaine may be substituted for ropivacaine). Total volume of 1 to 2 mL with or without 40 mg methylprednisolone, 4 mg dexamethasone, or 40 mg triamcinolone acetate, plus Omnipaque (Amersham Health, Buckinghamshire, England) (iohexol) water-soluble contrast 240 mg/mL (0.5 mL).

Anatomic Landmarks: The trigeminal ganglion lies in the Meckel cave at the apex of the petrous part of the temporal bone. The mandibular branch exits the foramen ovale and is partly enclosed by a dural cuff (see Fig. 23-3).