Forty-two patients with tic douloureux underwent posterior fossa craniectomy and microvascular decompression (MVD) or partial rhizotomy of the trigeminal nerve and were followed an average of 25 months after operation. Thirty-six patients were found to have anatomical distortions of the nerve by an artery, vein, bony prominence, or a combination of factors, and 30 patients (83%) of this groups hav remained pain-free postoperatively. Six patients had no discernible pathological condition at the time of operation and underwent partial trigeminal rhizotomy. No patient underwent repeated MVD or rhizotomy, although 4 patients whose pain recurred after MVD underwent rhizotomy at a second operation. Eight of the 10 patients treated by rhizotomy are currently pain-free. The overall success rate of the entire group is 90%; 2% experienced a complication, and there was 1 perioperative death. Seventy-eight patients with tic douloureux who underwent 92 percutaneous radiofrequency trigeminal gangliolysis (PRTG) procedures were evaluated on average of 56 months postoperatively. Sixty-eight per cent of these patients when evaluated 1 year postoperatively were pain-free. However, only 35% of the PRTG procedures resulted in continued pain relief 5 years after operation. Twelve of the 78 patients (15%) required repeat gangliolysis because of recurrent tic pain. Considering all 78 patients treated with 92 PRTG procedures, 64% were pain-free at follow-up examination. PRTG was associated wtih an 8% risk of complications, which included anesthesia dolorosa, corneal anesthesia with keratitis, and significant facial paresthesias. Both PRTG and MVD have advantages. MVD should be considered because: (a) it attacks what is believed to be the primary etiology of tic douloureux, (b) the trigeminal nerve is preserved, (c) postoperative pain relief dose not depend upon the production of sensory deficit, and (d) it may have a greater potential for producing long-lasting pain relief. However, PRTG has other advantages: (a) it avoids the risks of craniectomy, (b) it is repeated easily if tic pain recurs, (c) morbidity is minimal and there is essentially no risk of mortality, and (d) it is much less expensive.