Surgical Classification of Radical Temporal Bone Resection and Transcranial Tympanotomy: A Retrospective Study from the Neurosurgical Perspective

A Combined Exoscopic and Endoscopic Approach for Radical Temporal Bone Resection and Usefulness of the Endoscopic Approach to the Medial Aspect of the Temporal Bone

Radical temporal bone resection (TBR) for lateral skull base malignancies is technically challenging because of the vital anatomical structures located at the medial part of the temporal bone and their limited exposure. A possible solution is to adopt an additional endoscopic approach for medial osteotomy to reduce blind spots. The authors aimed to describe a combined exoscopic and endoscopic approach (CEEA) for cranial dissection in radical TBR and to determine the usefulness of the endoscopic approach to the medial aspect of the temporal bone. Having utilized the CEEA in for cranial dissection in radical TBR since 2021, the authors included 5 consecutive patients who underwent the procedure between 2021 and 2022. All surgeries were successful and resulted in no significant complications. The additional use of an endoscope improved visualization of the middle ear in 4 patients and that of the inner ear and carotid canal in 1 patient, enabling precise and safe cranial dissection. Furthermore, surgeons experienced reduced intraoperative postural stress with CEEA than with a microscopic approach. The main advantage of CEEA in radical TBR was the extension of the viewing angles of the endoscope, which allowed observation of the medial aspect of the temporal bone and limited tumor exposure and injury to vital structures. Given the other benefits of exoscopes and endoscopes, including compact size, ergonomics, and surgical field accessibility, CEEA proved to be an efficient treatment option for cranial dissection in radical TBR.

Combined Exoscopic and Endoscopic Technique for Craniofacial Resection

We determined the feasibility of the combined exoscopic-endoscopic technique (CEE) as an alternative to the microscope in craniofacial resection (CFR). This retrospective study was conducted at a single institution and included eight consecutive patients with head and neck tumors who underwent CFR between September 2019 and July 2021. During the transcranial approach, microsurgery was performed using an exoscope in the same manner as in traditional microscopic surgery, and an endoscope was used at the blind spot of the exoscope. The exoscope provided images of sufficient quality to perform microsurgery, while the sphenoid sinus lumen was the blind spot of the exoscope during anterior (n = 3) and anterolateral CFR (n = 2), and the medial aspect of the temporal bone was the blind spot of the exoscope during temporal bone resection (n = 2). These blind spots were visualized by the endoscope to facilitate accurate transection of the skull base. The advantages of the exoscope and endoscope include compact size, ergonomics, surgical field accessibility, and equal visual experience for neurosurgeons and head and neck surgeons, which enabled simultaneous transcranial and transfacial surgical procedures. All the surgeries were successful without any relevant complications. CEE is effective in transcranial skull base surgery, especially CFR involving simultaneous surgical procedures.

Variations of en Bloc Resection for Advanced External Auditory Canal Squamous Cell Carcinoma: Detailed Anatomical Considerations

Currently, only lateral temporal bone resection (LTBR) and subtotal temporal bone resection (STBR) are widely utilized for the surgical treatment of advanced squamous cell carcinoma of the external auditory canal (EAC-SCC). However, there are few descriptions of variations on these surgical approaches. This study aimed to elucidate the variations of en bloc resection for advanced EAC-SCC. We dissected the four sides of cadaveric heads to reveal the anatomical structures related to temporal bone resection. From the viewpoint of surgical anatomy, surgical patterns of temporal bone cutting can be divided into four categories: conventional LTBR, extended LTBR, conventional STBR, and modified STBR. Extended LTBR is divided into four types: superior, inferior, anterior, and posterior extensions. Several extension procedures can be combined based on the extension of the tumor. Furthermore, en bloc resection with the temporomandibular joint or glenoid fossa increases the technical difficulty of a surgical procedure because the exposure and manipulation of the petrous segment of the internal carotid artery are limited from the middle cranial fossa. Surgical approaches for advanced SCC of the temporal bone are diverse. They require accurate preoperative evaluation of the tumor extension and preoperative consideration of the exact line of resection to achieve marginal negative resection.