Kenning, Tyler

BACKGROUND: The lingual process of the sphenoid bone (LP) and the petrolingual ligament (PLL) surround laterally the internal carotid artery within the middle cranial fossa (MCF). OBJECTIVE: To study the LP and the PLL and anatomical variations considering their relationships with different structures and landmarks within the MCF, especially oriented toward the endoscopic endonasal approaches. METHODS: Seventy-two sides of dry skulls and 20 sides of embalmed specimens were studied. The measurements of the LP and the PLL were obtained, considering important landmarks in the MCF. RESULTS: The LP had a mean length and height of 5 mm and 3 mm, respectively. Its distance from the foramen lacerum was 6 mm, from the foramen ovale 10 mm, foramen rotundum 15 mm, and petrous apex 9 mm. In 44 sides (61.11%), the LP partially closed the lateral aspect of the carotid sulcus; in 17 sides (23.61%), it was found as a near-ring; and in 11 sides (15.2%), it was considered rudimentary. Considering the PLL, its length and height were, respectively, 9 mm, and 4 mm. CONCLUSION: The LP and PLL separate the carotid artery at the inferior aspect of Meckel's cave and constitute important landmarks for endoscopic endonasal approaches to Meckel's cave and MCF, and their identification and removal is essential for internal carotid artery mobilization in this area.

Abstract BACKGROUND The nasoseptal flap is the main pedicled flap used for endoscopic cranial base reconstruction. For large anterior cranial base defects, the anterior edge is a concern for the nasoseptal flap reach. OBJECTIVE To present a surgical technique that completely releases the vascular pedicle of the nasoseptal flap from the sphenopalatine artery (SPA) foramen improving considerably the reach of the flap. METHODS A patient with left anterior cranial base fracture involving the posterior table of the frontal sinus, who presented with cerebrospinal fluid leak and contused brain herniation to the ethmoid and frontal sinuses. Unilateral endoscopic endonasal anterior cranial base reconstruction was performed with left sided nasoseptal flap. The nasoseptal flap pedicle was dissected and completely released from the SPA foramen. The flap was left attached only to the internal maxillary artery (IMAX) vascular bundle. RESULTS The flap covered the entire left anterior cranial base, from the planum sphenoidale to the posterior table of the frontal sinus. There was complete obliteration of the cerebrospinal fluid fistula postoperatively with resolution of the radiographic pneumocephalus and the patient's rhinorrhea. CONCLUSION The complete release of the nasoseptal flap pedicle from the SPA foramen is feasible and remarkably improves the reach of the flap. It also increases the reconstructive area of the flap since the entire septal mucosa can be used for reconstruction and the pedicle length is based exclusively upon the SPA/IMAX.