Two series of patients with tic douloureux were followed up after surgery. In one series of 100 patients (Cleveland series) the extradural approach was used and the sensory root of the trigeminus was freed from its dural sleeve and otherwise manipulated; in the other (Copenhagen) series of 100 patients the approach was intradural, was less apt to traumatize the semilunar ganglion, and caused less postoperative sensory impairment. In the combined series, 62% of the patients reported complete relief, 11.5% had mild recurrences, and 26.5 % had severe recurrences. Some degree of sensory loss was present in 26% with successful treatment and in 28.3% of those in whom the treatment failed. Neither surgical trauma to the nerve root nor incision of its dural sleeve were essential to the success of the operation. The critical part of the operation appeared to be a neurolysis or manipulation of the sensory root at the point where it crosses the apex of the pars petrosa of the temporal bone.
Gardner WJ, Miklos MV. RESPONSE OF TRIGEMINAL NEURALGIA TO "DECOMPRESSION" OF SENSORY ROOTDISCUSSION OF CAUSE OF TRIGEMINAL NEURALGIA. JAMA. 1959;170(15):1773-1776. doi:10.1001/jama.1959.03010150017004