Systematic review of olfactory outcomes after nasoseptal flap harvest for endoscopic skull base surgery: Does using cold steel or olfactory strip preservation matter?

Background Several studies have described techniques aimed at mitigating olfactory dysfunction after nasoseptal flap (NSF) harvest for endoscopic skull base surgery (ESBS). No consensus exists as to whether popular methods including using cold steel (CS) versus electrocautery (EC) or septal olfactory strip (SOS) preservation offer an advantage. This systematic review was performed to examine the impact of these two technical variations of NSF harvest on postoperative olfactory outcomes. Methods Following PRISMA guidelines, PubMed, Scopus, and Web of Science were searched for articles reporting olfactory outcomes in ESBS cases employing an NSF. Original articles focusing on technique variations of the NSF and reporting at least one objective olfactory measure were included. Results Nine studies comprising 610 patients were included. Various, olfactory testing outcomes were reported, and postoperative follow‐up ranged from 6 weeks to 12 months. Three studies, including a randomized controlled trial, compared the use of CS and EC for the superior incision of the NSF. No significant difference was found in objective olfactory function (p > 0.05) when comparing these techniques. Five studies comprising 504 patients reported results from SOS‐sparing. SOS‐sparing technique in NSF harvest demonstrated smell preservation in the postoperative setting when compared with preoperative measures (p > 0.05); however, no direct comparison to non‐SOS‐sparing techniques was made. Conclusion The use of CS as opposed to EC for the superior NSF incision does not appear to confer an advantage in preserving postoperative olfactory function (grade B evidence). SOS preservation may be associated with better olfactory outcomes in NSF harvest (grade C evidence).