Intracranial microvascular decompression for "cryptogenic" hemifacial spasm, trigeminal and glossopharyngeal neuralgia, paroxysmal vertigo and tinnitus: I. Surgical technique and results.

Intracranial microvascular decompression was performed in 21 out of 24 patients with hyperactive dysfunction of cranial nerves: 8 cases of hemifacial spasm, 12 of trigeminal neuralgia, 3 of glossopharyngeal neuralgia and 1 case of paroxysmal vertigo and tinnitus. In 21 cases an abnormal vascular loop was found to impinge on the root entry zone of the nerve in the brainstem. Dissection of this loop with decompression of the nerve resulted in long-lasting relief of symptoms in all but two patients who presented early recurrence; in one of these a second procedure was eventually successful. In two patients with trigeminal neuralgia a benign tumor of the cerebellopontine angle that had escaped preoperative diagnosis was present. Finally, in one case no compressive lesions were found. From the data of the literature and from our present experience microvascular decompression can be considered a safe as well as an effective procedure, affording a high success rate in conditions often or usually resistant to medical treatment and erroneously considered "idiopathic".