Modified three-dimensional brain model for study of the trans-sylvian approach.

The trans-sylvian approach is one of the most frequently employed neurosurgical procedures, but it is difficult for medical students to understand the approach stereoscopically. A three-dimensional model equipped with an arachnoid membrane and sylvian vein was developed which can be repeatedly used to simulate surgery for the education of medical students and residents in the trans-sylvian approach. The model was prepared using existing models of the skull bone, brain, and cerebral artery. Polyvinylidene chloride film, commonly used as plastic wrap for food, was adopted for the arachnoid membrane, and wetted water-insoluble tissue paper for the arachnoid trabeculae. The sylvian vein was prepared by ligating woolen yarn with cotton lace thread at several sites. Students and residents performed the trans-sylvian approach under a microscope, and answered a questionnaire survey. Using this model, simulation of division of the arachnoid membrane and arachnoid trabeculae, and dissection of the sylvian vein was possible. In the questionnaire, the subjects answered 8 questions concerning understanding of the stereoscopic anatomy of the sylvian fissure, usefulness of the simulation, and interest in neurosurgical operation using the following ratings: yes, very much; yes; somewhat; not very much; or not at all. All items rated as 'yes, very much' and 'yes' accounted for more than 70% of answers. This model was useful for medical students to learn the trans-sylvian approach. In addition, repeated practice is possible using cheap materials, which is advantageous for an educational model.