Cerebrospinal Fluid Leakage Due to Dural Thinning after Endoscopic Pituitary Tumor Resection.

Sellar reconstruction is important for preventing cerebrospinal fluid (CSF) leakage after transsphenoidal pituitary surgery. This report describes how, despite standard sellar reconstruction, CSF exudation resulted from dural thinning at the anterior skull base, outside the intrasellar area manipulated during pituitary tumor resection. A 76-year-old man underwent endoscopic transsphenoidal surgery for a pituitary tumor extending toward the anterior skull base. After opening the sellar floor, intractable bleeding from the anterior intercavernous sinus occurred during bone removal at the anterior skull base. Pseudocapsule-based extracapsular resection was completed after stopping the bleeding. On the 10th postoperative day, the patient developed CSF rhinorrhea complicated by marked pneumocephalus, and emergency endoscopic repair of the CSF leak was performed. CSF leakage originated from the thinned dura at the anterior skull base located outside the intrasellar area manipulated during tumor resection. The thinned dural area at the anterior skull base coincided with the site of intractable bleeding of the anterior intercavernous sinus during bone removal in tumor resection. The thinned anterior skull base dura was covered with fascia, overlaid with fat, and closed with the nasoseptal flap. Endoscopic CSF leak repair was successful. Severe damage to the anterior intercavernous sinus can cause extensive exposure of the single-layered inner meningeal dura, where thinning might result in CSF exudation. Therefore, use of autologous tissues to cover and reinforce the severely damaged area of the anterior intercavernous sinus might help prevent postoperative CSF exudation.