2025 Proffered Presentations
S096: QUANTITATIVE CADAVERIC COMPARISON OF SURGICAL EXPOSURE IN COMBINED PETROSAL APPROACH V/S EXTENDED RSSO WITH STANDARD KAWASE APPROACH FOR ACCESS TO PETROCLIVAL AND VENTRAL BRAINSTEM REGIONS
Biren K Patel; Leonardo Tariciotti; Alejandra Rodas; Youssef Zohdy; J. Manuel Revuelta Barbero; Erion Jr De Andrade; Justin Maldonado; Samir Lohana; Rodrigo Uribe-Pacheco; Hanyao Sun; Roberto Soriano; Tomas Garzon-Muvdi; C.Arturo Solares; Gustavo Pradilla; Emory University
Introduction: The petroclival and ventral brainstem region present significant surgical challenges due to their deep location and proximity to critical neurovascular structures. Various approaches have been developed to access this area, including the combined petrosal (CP) approach, the extended retrosigmoid suboccipital (RSSO) approach, and the Kawase approach. Each offers unique advantages and limitations. This study aims to quantitatively compare the Combined Petrosal Approach versus the Extended RSSO with the Standard Kawase Approach to aid in surgical decision-making for complex skull base lesions in this region.
Objective: To quantitatively compare the surgical exposure, angle of attack, and volume of operative maneuverability provided by the combined petrosal approach as compared to the extended RSSO approach with the standard Kawase approach for accessing the petroclival region and ventral brainstem.
Methods: We used 4 latex-injected fresh cadaveric head specimens (8 sides). The CP approach was performed on one side and the extended RSSO approach along with Kawase approach was performed on the contralateral side of each specimen. Quantitative measurements included the area of exposure for petroclival region defined by a polygon connecting the following points: the posterior clinoid process, Meckel’s cave, internal acoustic canal, jugular foramen and two variable points (the highest and lowest point on the clivus). For calculating the ventral brainstem exposure, anatomical landmarks included root entry zones of trigeminal and facial nerve and three variable points on the brainstem (lowest medial, highest medial and highest lateral part). Angle of attack was measured at oculomotor foramen, Meckel’s cave, Dorello’s canal, root entry zones of facial nerve and trigeminal nerve. Measurements were taken using a stereotactic navigation system and analyzed statistically to compare the approaches.
Results: The Combined Petrosal approach provided the greatest overall exposure and volume of operative maneuverability, while the extended RSSO approach offered superior angles of attack to the ventral brainstem. The Kawase approach provided the most direct route to Meckel's cave and the upper clivus.
Conclusion: This study provides objective, quantitative data comparing these three surgical approaches. Results can guide surgical decision-making for lesions in the petroclival and ventral brainstem regions, potentially improving patient outcomes by allowing surgeons to choose the most appropriate approach based on lesion location and extent.
Keywords: Combined petrosal approach, extended retrosigmoid approach, Kawase approach, petroclival region, ventral brainstem, skull base surgery, cadaveric study