Endoscopic skull base surgery II: a new animal model for surgery of the posterior fossa.

The field of skull base surgery has been influenced by a general philosophy that currently exists in modern surgical practice favoring less invasive means of managing surgical disease. Adapting techniques developed by general surgeons and other surgical subspecialists, skull base surgeons are now experimenting with endoscopy to resect tumors, manage vascular lesions, and manipulate critical intracranial structures. Lesions formerly requiring significant soft tissue dissection and craniotomy for exposure are now potentially amenable to treatment via a keyhole approach. As in other surgical specialties, however, a reliable animal model is necessary for experimentation with and development of new endoscopic techniques in the skull base. The swine provides just such a model, primarily due to craniofacial and skull base relationships that are analogous to humans. We have focused on the posterior skull base of the swine in this experiment: Via a retrosigmoid craniotomy we opened the dura of the posterior fossa and used endoscopes to visualize and manipulate the critical structures in this area. The cerebellum and midbrain were appreciated, as were cranial nerves V, VII, VIII, IX, X, and XI. Blood vessels on the surface of the midbrain were also identified. This experience further supports the use of the swine as an appropriate animal model for endoscopic skull base surgery.