Anatomical Cadaveric Study of the Most Medial Osteotomy in En Bloc Subtotal Temporal-Bone Resection

Background: En bloc subtotal temporal-bone resection (STBR) is a surgical technique used for the removal of temporal-bone malignancies. STBR requires a skull-base team and remains a challenging procedure. Numerous reports describe the classical STBR technique. From a microsurgical anatomical standpoint, en bloc STBR consists of three approaches: the high-cervical, subtemporal–infratemporal fossa, and retromastoid–paracondylar approaches. However, few reports detailing resection of the most medial bone in this procedure have been published, although it is the most technically challenging aspect of en bloc STBR. Objectives: In this study, we focused on the anatomical details of resection of the most medial bone in en bloc STBR, and we discuss the surgical nuances involved. Methods: Dissections were performed on 10 formalin-fixed cadaveric specimens. Following the subtemporal–infratemporal fossa and retromastoid–paracondylar approaches, resection of the medial portion to complete en bloc STBR was examined. Results: To achieve en bloc STBR, we had to safely remove the bone within a triangular area anterior to the jugular fossa, posterior to the posterior genu of the petrous segment of the internal carotid artery, and directly above the carotid ridge on the medial side of the styloid process base. The region to be resected had mean (range) dimensions of 1.59 (1.2–2.5) mm anteriorly, 1.65 (1.2–2.5) mm posteriorly, and 1.0 (0.8–1.2) mm medially, with a total area of 0.76 (0.47–1.46) mm2. Conclusion: En bloc STBR is a complex and technically demanding procedure, with the medial bone being the most challenging component to resect. To minimize the most medial triangular bony region, meticulous bone removal is necessary from three directions: 1) from the middle cranial fossa, 2) from the posteroinferior aspect after separation of the jugular bulb venous wall from the jugular fossa, and 3) from anterolateral aspect after anterior displacement of the petrous carotid artery. Thorough bone removal in this region enabled the successful completion of en bloc STBR. This study emphasizes the importance of understanding the anatomical features of the medial bone for en bloc resection. It aims to contribute to the refinement of surgical techniques for temporal-bone resection. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany