We report 2 cases of microvascular decompression of the nervus intermedius. The current views of aetiology of neuralgia and spasm of the cranial nerves are discussed based on intraoperative observations and electro-optical investigation reported in the literature. The complex anatomy within the sensory system of the facial nerve, and the intersection of its area of supply with that of the glossopharyngeal and vagus nerves are discussed. Surgical treatment is proposed with emphasis on the current preoperative difficulties of interpretation and the intraoperative constant variations in the course of the anterior inferior cerebellar artery.