A Report of Two Cases of Planum Sphenoidale Injuries With Cerebrospinal Rhinorrhea Following Office Balloon Dilation of the Sphenoid Ostium: Lessons Learned.

Balloon-assisted dilation (BAD) of paranasal sinus ostia is a Food and Drug Administration (FDA)-approved minimally-invasive procedure used to treat medically refractory chronic rhinosinusitis. Several large cohort studies have reported relatively-low complication rates with BAD. Thus, users of this technology may perceive this to be a safer alternative to formal dissection of the frontal and sphenoid sinus and perform these as office-based procedures. Here, we present 2 patients who underwent BAD of the sphenoid sinus and developed cerebrospinal fluid leak (CSF) leaks with pneumocephalus. Both patients had thinning of the planum sphenoidale in generously-pneumatized sphenoid sinuses. Although BAD is considered safe, review of the current literature demonstrates that serious complications can occur. These case reports demonstrate the potential for skull base injury, particularly in hyper-pneumatized sphenoid sinuses with dehiscent bone. Preoperative anatomic evaluation is crucial to identify at-risk patients. During BAD, trauma to critical structures may cause CSF leak and result in pneumocephalus. This knowledge is important for improving surgical decision-making and patient counseling.Level of Evidence: III.