Long-term olfactory outcome after nasoseptal flap reconstructions in midline skull base surgery

Background: The nasoseptal flap (NSF) is a universally used surgical technique to cover defects of the skull base after extended sinonasal surgery. Long-term follow-up of complications, sequelae, and smell function is largely unknown. Objective: The main objective of this study was to investigate monorhinal olfaction after transsphenoidal skull base surgery. Methods: Patients who underwent skull base surgery for midline lesions (craniopharyngioma and pituitary tumors) by using a NSF, also referred to as the Haddad flap, were assessed for their long-term outcome. Endoscopic examination was conducted and the bilateral "Sniffin' Sticks" test was performed before surgery. Each side was tested separately in the postoperative follow-up consultation. Results: Twenty patients were included in the study. No flap failures were observed. One anterior perforation and one small posterior septal perforation were found during long-term follow-up. None of the patients had nasal breathing impairment, whereas two patients had nose bleeds. A significant decrease in olfactory function was observed on the flap donor side in four patients (20%) compared with that observed in one patient (5%) on the opposite side. Conclusion: NSF reconstructions for midline lesions were efficient and safe in the long term. Olfactory impairment on the donor side was frequently encountered. Although subclinical, these findings justified a monorhinal smell testing before surgery, which possibly prevented bilateral smell impairment in patient with preexisting single-sided olfactory loss.