2025 Proffered Presentations
S344: ANATOMICAL STEP-BY-STEP DISSECTION OF COMPLEX SKULL BASE APPROACHES FOR TRAINEES: MEDIAL CAVERNOUS SINUS WALL RESECTION
A. Yohan Alexander1; Ramin A Morshed, MD2; Carlos D Pinheiro Neto, MD, PhD1; Maria Peris-Celda, MD, PhD1; 1Mayo Clinic; 2University of California San Francisco
Introduction: Resecting the medial wall of the cavernous sinus (MWCS) maximizes the chance of biochemical cure in patients with functioning pituitary adenomas. This technique, however, may be challenging for trainees to understand given the complexity of sellar anatomy and sequence of surgical steps. This study aims to provide an anatomically oriented, step-by-step guide for MWCS resection with representative clinical cases and videos.
Methods: On 10 sides of five formalin-fixed, latex-injected specimens, endoscopic endonasal transsellar-transcavernous approaches followed by resection of the MWCS were performed using a 0-degree endoscope. Key surgical steps were documented in 3D on illustrative specimens. Dissections were supplemented with representative case applications and videos demonstrating the technique in step-by-step fashion.
Results: Steps involved in resecting the MWCS include a sphenoidotomy, a sellar osteotomy that exposes the periosteal dura overlying the MWCS ipsilateral to the lesion, an inferior intercavernous incision of periosteal dura that begins in midline of the inferior intercavernous sinus and is carried laterally and superiorly to expose the ipsilateral cavernous sinus, incision of the meningeal dura covering the pituitary gland, removal of tumor (simulated by removing the lateral one-third of the pituitary gland), incisions at the roof and floor of meningeal layer that meet posteriorly (thus freeing the MWCS from its medial attachments), and, lastly, sharp disconnection of the sellar ligaments which tether the MWCS laterally. The MWCS is then removed. Videos of two illustrative cases – one growth hormone secreting adenoma and one ACTH secreting adenoma – are also presented to illustrate the intraoperative key surgical steps and the clinical utility of this technique.
Conclusion: We present the surgical steps involved in resection of the MWCS in a step-by-step fashion with surgically oriented anatomical dissections. Further, we depict when MWCS resection would be indicated with two illustrative clinical cases.
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