Iatrogenic Cerebrospinal Leak Arising from a Persistent Fonticulus Frontalis

Congenital midline nasal anomalies are rare; however, when present the typical result is a glabelar mass that presents in childhood. The persistence of an asymptomatic fonticulus frontalis in an adult is thought to be a rare event. We report a case of a 71-year-old man with chronic rhinosinusitis who underwent image-guided endoscopic sinus surgery including Draf 2A frontal sinusotomy. During frontal sinus dissection, a suspected cerebrospinal fluid leak was encountered anteromedial to the right frontal ostium. Image-guided navigation demonstrated the defect was not adjacent to the cribriform plate. The defect was repaired intraoperatively using a free mucosal graft from the septum. Upon review of the sagittal and axial CT imaging, the patient was noted to have a persistent fonticulus frontalis that was encountered while enlarging the medial aspect of the frontal ostium. This case calls attention to the potential relevance of a persistent fonticulus frontalis as a risk factor for cerebrospinal fluid leak in adults undergoing endoscopic sinus surgery. Identification of this anatomic variant should be considered during the preoperative assessment.

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