Olfactory changes after endoscopic endonasal transsphenoidal approach for skull base tumors

Objectives/Hypothesis The increased number of endoscopic endonasal transsphenoidal approaches (EETSA) has been associated with sinonasal complications such as olfactory dysfunction. Current studies have compared preoperative and postoperative olfactory function according to surgical type and age. Study Design Retrospective review of medical records at a tertiary referral center. Methods Patients were divided into two groups according to surgical type and into four groups according to age. The two surgical groups were defined based on the bilateral nasoseptal flap technique (group A: right conventional nasoseptal flap and left modified nasoseptal rescure flap; group B: bilateral modified nasoseptal rescue flap). The four age groups were ≤ 30, 31-45, 46-60, and ≥ 61 years. Patients underwent preoperative olfactory function evaluation using a visual analogue scale (VAS), the Connecticut Chemosensory Clinical Research Center Test (CCCRC), and the Cross-Cultural Smell Identification Test (CCSIT). Repeat testing was performed 6-months postoperatively. Results A total of 226 patients who underwent binostril four-hand EETSA were included in this study. In both groups A and B, the olfactory function was significantly decreased according to CCCRC and CCSIT scores (P < 0.05). The VAS scores were significantly decreased in both groups (P < 0.05). The symptom scores and olfactory test results were significantly changed in >30-year-old patients who had undergone EETSA. Conclusion EETSA might contribute to olfactory dysfunction independent of surgery type. In addition, age may affect the restoration of olfaction after EETSA. Patients who plan to undergo EETSA must be informed that their olfaction may be impaired.