Endoscopic Endonasal Approach to the Lateral Wall of the Cavernous Sinus: A Cadaveric Feasibility Study

Abstract

Objective: A transcranial extradural approach to the middle cranial fossa (MCF) requires separation of the dural layers of the lateral wall of the cavernous sinus. The authors tested the feasibility of an endonasal approach for this separation. Methods: A cadaveric feasibility study was conducted on the sides of 14 dry skulls and 10 fresh cadaveric heads. An endonasal, transsphenoidal, transpterygoid approach was taken to the MCF. The maxillary struts and medial greater wing of the sphenoid below the superior orbital fissure were drilled with transposition of the maxillary nerve. The lateral cavernous dural layers were split at the maxillary nerve with separation of the temporal lobe dura and exposure of the MCF bony base. The integrity of the cranial nerves and inner and outer dural layers of the lateral cavernous wall was checked. Different measurements of bony landmarks were obtained. Results: The integrity of the dural layers of the lateral cavernous wall and the cranial nerves were preserved in 10 heads. The mean area of the bony corridor was 4.68 ± 0.97 cm 2 , the V2-to-V3 distance was 15.21 ± 3.36 mm medially and 18.21 ± 3.45 mm laterally, and the vidian canal length was 13.01 ± 3.06 mm. Conclusions: Endonasal endoscopic separation of the lateral cavernous dural layers is feasible without crossing the motor cranial nerves, allowing better exposure of the MCF.

Middle cranial fossa trigeminal schwannoma resection through endoscopic transnasal maxillary sinus approach: A case report and literature review

“…Conventional skull base surgical approaches, such as the lateral approach of the middle cranial fossa or anterior transpetrosal approach, are usually used to resect middle cranial fossa lesions but are often too invasive. Notably, these approaches could result in significant surgical complications with narrow operative corridors ( 23 ), including occlusion obstacles, temporalis muscle atrophy, facial lesions, peripheral facial paralysis and temporal lobe retraction ( 8 ), whereas endoscopic surgery has an advantage over these approaches in this regard ( 24 ). Endonasal endoscopic procedures were first used for pituitary surgery and their use has been gradually extended to other regions; in particular, these procedures are now the major approach for operating on lesions located in the skull base, including the orbit ( 25 ), parasellar space ( 26 ) and Meckel's cave ( 27 ).…”

Resection of Pituitary Tumor with Lateral Extension to the Temporal Fossa: The Toothpaste Extrusion Technique

“…Decisions about approaches often depend on tumor size, location, and operator experience. Tumors extending lateral to the carotid (e.g., Knosp grade 2 or higher) often present challenges during transsphenoidal approaches, requiring extended endoscopic techniques [11][12][13]. Similarly, lesions extending lateral and beyond cranial nerves create a challenge endonasally [1][2]14].…”