Endoscopic transoral-transclival approach to the brainstem and surrounding cisternal space: Anatomic study

OBJECTIVE: The purpose of this study was to review the endoscopic anatomic features of the anterior brainstem and surrounding cisternal spaces via a transoral-transclival approach. METHODS: Fifteen adult human cadaveric heads, obtained from 10 fresh cadavers and 5 formalin-fixed cadavers, were used to demonstrate both the feasibility of an endoscopic transoral-transclival intradural approach and its exposure potential. To analyze the exact extension of a safe entry zone through the clivus, 20 skull bases were used to obtain anatomic measurements. RESULTS: The transoral approach was performed without maxillotomy or mandibu- lotomy and with a clival opening of 20 by 15 mm. Such a limited clival and dural opening allowed the insertion of the endoscope and instruments, full visualization of the anterolateral brainstem and cisternal spaces around it, and reconstruction of all anatomic layers by means of a paraendoscopic technique. CONCLUSION: The endoscopic transoral-transclival approach enables full access to the anterolateral brainstem and to the cisternal space around it. The use of the endoscope has the potential to reduce the need for a wider cranial base opening and the danger of postoperative complications.