Contrary to widely held beliefs, the gene encoding proteolipid protein (PLP), the major structural protein of central nervous system myelin, is expressed in Schwann cells and their tumors. Proteolipid mRNA was identified in human acoustic neuromas and in rat and rabbit sciatic nerves using a human PLP cDNA as a probe. Proteolipid protein itself was shown to be present in human and rat sciatic nerve Schwann cells by immunofluorescence microscopy and by Western blot analysis using antisera raised to a synthetic PLP polypeptide. Although easily detected in the Schwann cell body, PLP was not detected in the peripheral myelin itself, suggesting that the PLP is preferentially excluded from this portion of the Schwann cell membrane.

The improved survival of patients sustaining massive head injuries has increased the number of temporal bone fractures being managed by otolaryngologists and neurosurgeons. We performed a prospective analysis of 35 patients with head injury with temporal bone trauma. The major emphasis of this study was to investigate the incidence, management, and outcome of facial nerve injury in such patients and to evaluate the importance of electrodiagnostics in the surgical management of the facial nerve. The results of this study indicate an incidence of fracture type, hearing loss, and facial nerve paralysis similar to that already recorded in the literature. This study underscores the importance of evoked electromyography, or electroneuronography, in assessing facial nerve function. Electroneuronography provided the indications for surgical intervention for facial paralysis. All patients having surgery for facial paralysis as determined by electroneuronographic findings had pathology of the facial nerve.

Osteomyelitis of the skull base is the most severe form of malignant otitis externa. As a result of having treated 13 patients with skull base osteomyelitis over a 4-year period, we have developed a method of staging and monitoring this malady using gallium and technetium scanning techniques. Stage I is localized to soft tissues, stage II is limited osteomyelitis, and stage III represents extensive skull base osteomyelitis. All stages are treated with appropriate antipseudomonal antibiotics. The duration of therapy depends upon the clearing of inflammation as shown on the gallium scan. Each case must be looked at independently and not subjected to an arbitrary treatment protocol.

AlloDerm is a suitable material for TM grafting. This product is especially valuable in revision surgery in which the availability of appropriate autologous grafting material is limited.