Intracranial Mucocele following Iatrogenic Cerebrospinal Fluid Leak Repair

Objectives Iatrogenic cerebrospinal fluid (CSF) leaks are now commonly repaired using endoscopic approaches with high success rates. Mucocele formation is a rare complication associated with these repairs. Here, we describe a large iatrogenic ethmoid mucocele, occurring post-CSF leak repair with significant intracranial extension. Salient features of the evaluation, diagnosis, and management are presented with suggestions for prevention.

Methods Case report and review of the literature.

Case Report An otherwise healthy 57-year-old man with chronic rhinosinusitis and nasal polyposis (CRSwNP) presented after undergoing an ethmoidectomy and balloon sinuplasty at an outside hospital complicated by an iatrogenic CSF leak. A defect of the left anterior ethmoid roof was repaired intraoperatively at the time of injury. Although the patient was without recurrent CSF leak or central-type symptoms, his CRSwNP necessitated a CT scan which demonstrated extensive sinonasal polyposis, pansinusitis, and extrusion of a cystic lesion through a bony dehiscence of the left ethmoid skull base. MRI demonstrated an intracranial mucocele with mass effect. The patient subsequently underwent a combined rhinology/neurosurgery endoscopic resection of the mucocele with skull base defect repair. Pathology was consistent with a mucocele. The patient did well postoperatively, and MRI at 1 year demonstrated no recurrence of the intracranial mucocele.

Conclusion Complications relating to repair of sinonasal CSF leaks can include mucocele formation with significant intracranial extension. Surgical technique and appropriate graft orientation may reduce the risk of occurrence. In cases of significant intracranial extension, marsupialization alone may be insufficient, as only complete removal of the cyst lining will prevent recurrence above the level of the skull base repair. A combined team approach is suggested with the decision for endoscopic versus open approach based on individual case characteristics.