Mucocele formation under pedicled nasoseptal flap

Abstract

The pedicled nasoseptal flap has become an indispensible tool for the reconstruction of skull base defects. This flap is easily harvested, provides a large surface area of vascularized tissue, and has few reported complications. We describe the case of a 60-year-old man who underwent endoscopic, endonasal transsphenoidal surgery with septal flap reconstruction who developed a sphenoid sinus mucocele postoperatively. We also have reviewed the literature for similar findings and discuss this complication in the setting of pituitary surgery and endoscopic skull base repair. Although likely a rare occurrence, mucocele formation after septal flap reconstruction should be recognized and monitored with postoperative nasal endoscopy and radiologic imaging. Reoperation or mucocele drainage may be necessary if symptomatic or in cases of rapid enlargement.

Introduction

A 60-year-old man presented with a 2-year history of visual loss and headache. Brain magnetic resonance imaging (MRI) showed a large partially necrotic sellar and suprasellar mass compressing the optic chiasm. He was subsequently taken to the operating room for endoscopic, endonasal transsphenoidal tumor resection. During the course of complete tumor removal, a cerebrospinal fluid leak developed. The skull base defect was filled with an abdominal fat graft, and the sellar face was reconstituted with a porous polyethylene implant (Porex Surgical, Inc, Newnan, GA) placed beneath the sellar bone margins. The mucosa overlying the sphenoid cavity and clival recess was then removed, and a left-sided septal flap was elevated and rotated into place to cover the skull base defect. The flap was coated with a layer of fibrin sealant (Tisseel; Baxter Healthcare corporation, Deerfield, IL) and supported by several pieces of absorbable gelatin sponge (Gelfoam; Pharmacia & Upjohn, Kalamazoo, MI). No lumbar drain was used during or after surgery. The patient had an unremarkable postoperative course with no evidence of cerebrospinal fluid leak and was subsequently discharged on postoperative day 4. Final pathology was consistent with a follicle stimulating hormone-secreting pituitary adenoma.

The patient did well over subsequent months with resolution of his headaches and visual field deficits. Follow-up MRI performed 4 months after surgery showed complete resection of the tumor but with development of a small mucocele under a portion of the septal flap (Fig. 1). Nasal endoscopy showed an open, fully mucosalized sphenoid cavity, and the patient was asymptomatic with respect to sinonasal symptoms. A second follow-up MRI performed 2 years after surgery again showed no evidence of residual or recurrent tumor. However, along the right inferior portion of the sphenoid cavity, a hyperintense 15 × 15 mm mass, consistent with an enlarging mucocele, was again noted (Fig. 2). Nasal endoscopy showed an unremarkable posterior septectomy defect with the septal flap adherent to the sphenoid wall and skull base. There was, however, a notable prominence along the right sphenoid wall, consistent with the radiologic finding of a sphenoid cavity mucocele (Fig. 3). Given that the patient remained asymptomatic, continued observation was elected.