The endonasal midline inferior intercavernous approach to the cavernous sinus: technical note, cadaveric step-by-step illustration, and case presentation

Purpose Traditional endoscopic endonasal approaches to the cavernous sinus (CS) open the anterior CS wall just medial to the internal carotid artery (ICA), posing risk of vascular injury. This work describes a potentially safer midline cellar entry point for accessing the CS utilizing its connection with the inferior intercavernous sinus (IICS) when anatomically present.Methods The technique for the midline intercavernous dural access is described and depicted with cadaveric dissections and a clinical case.Results An endoscopic endonasal approach exposed the periosteal dural layer of anterior sella and CS. The IICS was opened sharply in midline through its periosteal layer. The feather knife was inserted and advanced laterally within the IICS toward the anterior CS wall, thereby gradually incising the periosteal layer of the IICS. The knife was turned superiorly then inferiorly in a vertical direction to open the anterior CS wall. This provided excellent access to the CS compartments, maintained the meningeal layer of the IICS and the medial CS wall, and avoided an initial dural incision immediately adjacent to the ICA.Conclusion The midline intercavernous dural access to the CS assisted by a 90 degrees dissector-blade is an effective modification to previously described techniques, with potentially lower risk to the ICA.