Abdominal Fat Graft for Reconstruction of the Anterior Skull Base for Endonasal Transsphenoidal Surgery: Technique and Outcomes

Background The transsphenoidal approach is standard of care for the treatment of pituitary adenomas, and is increasingly employed for the surgical management of a variety of anterior skull base tumors. Persistent postoperative cerebrospinal fluid (CSF) leaks can become a major concern, and may result in significant complications including meningitis, pneumocephalus, and potentially intracranial hemorrhage. Postoperative CSF leak rates reported after endoscopic transsphenoidal surgery vary widely, from 0.1 to 17%. We review current and past methods of skull base repair reported in the literature, and report our technique and results which benefit from a 49-year experience with transsphenoidal surgery. We describe the evolution of our standard technique utilizing abdominal fat graft as the primary means of sellar reconstruction and prevention of postoperative CSF leaks.

Methods A recent consecutive series (2008–2017) of 865 patients who underwent 948 endonasal procedures for lesions of the sella and anterior skull base at one center was retrospectively reviewed. Four hundred and thirty (383 endoscopic, 13 microscopic, and 34 combined) patients underwent reconstruction of the sellar defect with an abdominal fat graft. Routine intraoperative or postoperative lumbar drains were not used in this population. Abdominal fat was obtained via a subumbilical incision and divided into small thumbnail sized pieces. Fat graft was coated with wisps of cotton and microfibrillar collagen hemostat (Avitene, Integra, Somerville, New Jersey, United States). Postoperative outcomes were reviewed to evaluate all other complications.

Results Of the abdominal fat grafts performed, 358 (83.3%) were performed for intraoperative CSF leak. Fat grafts were placed for the following diagnoses: 284 adenomas (66.0%), 51 Rathke’s cleft cysts (11.9%), 34 craniopharyngiomas (7.9%), 4 meningiomas (0.9%), 11 arachnoid cysts (2.6%), 6 chordomas (1.4%), 4 inflammatory/autoimmune etiologies (0.9%), 5 other tumors of the sellar region (1.2%), 3 metastatic tumors (0.7%), 2 epidermoids (0.5%), 15 prior CSF leaks (3.5%), 3 revisions for hematoma/visual loss (0.7%), 1 chiasmapexy (0.2%), 1 apoplexy (0.2%), and 6 nondiagnostic samples (1.4%). Twenty patients (4.7%) developed persistent postoperative CSF leaks requiring reoperation with the following diagnoses: seven adenomas (1.6%), seven craniopharyngiomas (1.6%), two arachnoid cysts (0.47%), two prior CSF leaks (0.47%), one meningioma (0.23%), and one Rathke’s cleft cyst (0.23%). Nasal septal flaps were used in conjunction with fat grafts in 42 patients (22 craniopharyngiomas, 7 adenomas, 4 meningiomas, 4 prior CSF leaks, 1 Rathke’s cleft cyst, and 4 other pituitary etiologies). Three patients (0.6%) developed minor abdominal donor-site complications requiring reoperation: one hematoma and two wound complications with one found to have an odd persistent infection with Mycobacterium abscessus.

Conclusion Minimizing postoperative CSF leaks following endonasal anterior skull base surgery is important to decrease morbidity and to avoid a prolonged hospital stay. We present an evolutionary technique of abdominal fat grafting that is effective and safe and include minimal morbidity and expense.