From 1976 to 1986, 681 patients with drug-refractory trigeminal neuralgia (TN)--typical in 641, symptomatic of multiple sclerosis in 23 and of tumor in 10, atypical in 5, and postherpetic in 2--were treated with various percutaneous procedures. Controlled differential thermocoagulation of the gasserian ganglion and/or retrogasserian rootlets was performed in 533 patients; glycerolization of the trigeminal cistern in 32; and compression of the gasserian ganglion by balloon catheter in 159. Results and complications of each procedure are assessed at a mean follow-up of 6.5 years for thermocoagulation, 5 years for glycerolization, and 3.5 years for compression. The following therapeutic protocol is proposed: 1) in TN patients at first operation: a) gasserian compression (or glycerolization, if experience warrants it) is indicated in all cases of typical TN, unless the 3rd division alone is affected; b) in the latter case and in symptomatic TN, we suggest thermocoagulation; 2) in recurrences: a) after glycerolization or gasserian compression, gasserian compression (or glycerolization) is indicated; b) after thermocoagulation or open surgery, thermocoagulation is suggested.