Olfactory functions after transsphenoidal pituitary surgery: Endoscopic versus microscopic approach

Objectives/Hypothesis: Olfactory disturbances could be observed following transsphenoidal pituitary surgeries. To our knowledge, no previous comparative studies on olfactory functions after transsphenoidal endoscopic and microscopic approaches have been performed. Study Design: Prospective study comparing olfactory functions between endoscopic and microscopic transsphenoidal pituitary surgery. Method: Twenty-five patients operated on with the endoscopic approach and 25 patients operated on with the microscopic transsphenoidal approach have been evaluated. The Smell Diskettes Olfaction Test was used during the preoperative period, 1 month after the operation, and 6 months after the operation. In addition, the relationship between intraoperative cerebrospinal fluid leakage from the pituitary and postoperative synechiae formation with olfaction system was evaluated. The results were analyzed using the Friedman test, Mann-Whitney test, and Chi-Square test. Results: In the endoscopic group, there were two hyposmic patients and no anosmic patients. In the microscopic group, there were 13 hyposmic patients and five anosmic patients. The data was statistically different between both groups (P < 0.05). Cerebrospinal fluid leakage was observed in nine patients in the endoscopic group and in 10 patients in the microscopic group. There was no statistically significant difference between cerebrospinal fluid leakage and olfactory disturbances in both groups (P > 0.05). Synechia was observed in nine patients in the microscopic group and in only one patient in the endoscopic group. There was a statistically significant difference between the presence of synechia and olfactory disturbances (P < 0.05). Conclusions: This is the first study to seek the difference between the endoscopic and microscopic transsphenoidal approaches on the olfactory system during pituitary surgery. The obtained results indicate that an endoscopic approach seems to be more advantageous than a microscopic approach for protecting olfactory system and function.