[Results of microsurgical decompression in trigeminal neuralgia.].

INTRODUCTION

From 1 August 1983 to 6 June 1992, 284 patients underwent decompression of the trigeminal root in the rear part of the skull as treatment for tic douloureux. According to preoperative diagnosis and intraoperative inspection, a space-occupying process was the cause of the typical neuralgia in 13 cases (4 meningiomas, 3 epidermoid tumours, 3 acoustic neuromas and 2 trigeminal neuromas). In 271 cases (95.4%) microsurgical vascular decompression according to Jannetta was carried out.

METHODS

The majority of patients were between 45 and 75 years of age. The follow-up period ranged from 10 months to 9.3 years (average 59.45 months). The results of the long-term investigations are based on standardized questionnaires completed by 202 patients. Of the total of 271 patients operated upon by Jannetta's technique, 261 (96.3%) were free of pain immediately after the operation. The main causes of failure were misdiagnosis (myoarthropathy, cluster headache) and incorrect indications (encephalomyelitis disseminata, trigeminal neuropathy following peripheral lesion). In 3 cases vascular displacement and complete decompression of the trigeminal root were impossible because the basilaris was exceptionally long.

RESULTS

In the long term, 87.6% of the patients operated on remained free of pain or improved sufficiently to require no further carbamazepine medication. Relapses developed in 7.4% of cases, and except for operative revision and rhizolysis of the trigeminal root in a case of relapsed trigeminal neuralgia, thermo-controlled high-frequency lesion of the gasserian ganglion was carried out in a second operation. The complications of the Jannetta operation were hypoacusis and anacusis (4%), hyposmia (1%), dizziness (3.5%) and chronic subdural haematoma (1 case). Neither postoperative bacterial meningitis nor any lethality was recorded. In 94.5% of cases the patients expressed positive opinions of the operation and its results, while 4% regretted having the operation and 1.5% were undecided. The question as to whether the operation had significantly improved the quality of life was answered in the affirmative by 88.4% of the patients.

DISCUSSION

In summary, the long-term results confirm that microsurgical vascular decompression can be offered as the method of choice for treatment of trigeminal neuralgia in younger patients, and in older patients when cardiopulmonary risk factors and cerebrovascular processes can be eliminated. Alternative methods are high-frequency lesionsing of the gasserian ganglion according to Sweet and chemorhizolysis of the gasserian ganglion, but these must be restricted exclusively to the treatment of typical trigeminal neuralgia with tic douloureux. Persistent neuropathic pain caused by atraumatic or drug-induced lesion to the trigeminal nerve cannot be positively influenced either by surgical decompression or by destructive operations on the gasserian ganglion.