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Abstract:
Intratemporal lesions of the facial nerve can be divided into operative lesions, lesions due to birth trauma, trauma through the external auditory canal, gunshot injuries, lesions caused by fractures of the temporal bone and lesions due to intratemporal tumours. Bell's palsy and palsies due to inflammation are not included in this paper. The lesions caused by fractures are discussed in more detail. In longitudinal fractures the nerve is always damaged at the site of the geniculate ganglion and not at the pyramidal segment, as accepted until now. Of the lesions caused by tumours the neurinomas are discussed. A very rare case of a combined extra- and intra-temporal neurinoma is presented. The progress of the electrophysiological findings (nerve excitability test, electroneurography) are most important for the indication for exploration of the nerve, especially in lesions due to fracture. Surgery is necessary only in cases of imminent or complete denervation and not in cases of neuropraxia. The methods of intratemporal facial nerve surgery are: 1. anastomoses (cross-over) between the facial nerve and other cranial nerves (IX, XI, XII), 2. decompression, 3. suture (including rerouting), and 4. nerve grafting. The oldest method of anastomosing with the hypoglossal nerve, is a useful technique if other techniques of nerve repair have failed. Since the introduction of transtemporal surgery of the internal canal decompression can bedone from the stylomastoid foramen to the porus acousticus. The end-to-end suture of a severed nerve gives good results. Nerve defects can be corrected by shortening the nerve bed. The following methods are used: 1: rerouting of the pyramidal segment (Bunnel, Martin), 2. rerouting at the stylomastoid foramen (Mundnich), 3. transtemporal rerouting of the first genu (Ganglion geniculi) with preservation of the labyrinth (one case is demonstrated). 4. transmastoidal-translabyrinthine rerouting in cases of a destroyed labyrinth. Nerve grafting is the method of choice with large defects. In the temporal bone special suture techniques are unnecessary. The approximation of the stumps must be free of tension.