LAUSR

Interest in endoscopic transnasal access has increased with continued technological advances in endoscopic technology. OBJECTIVE The goals of this study were to review the normal anatomy in transnasal endoscopic neurosurgery and outline the anatomical basis for an expanded surgical approach. Defining anatomical aspects of surgical endoscopy helps guide the surgeon by defining normal anatomy of the access vector. METHODS this anatomic study was conducted on 15 adult male cadaver specimen using various microsurgical tools and endoscopic instruments and 1 intraoperative case. The vasculature was injected with colored silicone to aid visualization. Different transnasal approach techniques were used, with angle of endoscope access at 0°, 30°, 45° and 70° accordingly for extensive anatomical mapping. RESULTS the proximity of critical structures is different in each approach degree, a full understanding of the possible structures to be met during transnasal access is described. As a result of the study, anatomical aspects and important structures were outlined, a surgical protocol was defined for minimal risk access in respect to normal anatomy of the area. CONCLUSIONS thorough knowledge of topographic anatomy of the craniovertebral junction is required for performing minimal-risk surgical intervention in this region. It is important to know all anatomical aspects of the transnasal approach in order to reduce the risk of damage to vital structures. Transnasal endoscopic surgery of the craniovertebral junction is a relatively new direction in neurosurgery, therefore anatomical studies such as the one described in this article are extremely important for development of this access method.