Chemosensory Dysfunction and Recovery in Endoscopic Endonasal Skull Base Surgery

The investigators hypothesize that patients undergoing endoscopic endonasal skull base surgery experience clinically meaningful and modifiable disruptions in postoperative chemosensory function and quality of life, and the investigators further hypothesize that olfactory training in the postoperative period may significantly hasten normalization of patients' chemosensory perturbations. This tailored prospective study seeks to fulfill a significant gap in the understanding of the characteristics, implications, and treatment options for postoperative olfactory and gustatory impairment following endoscopic endonasal skull base surgery.

All study team members and study participants are blinded as to which olfactory training kit (treatment vs placebo) the participants received.

Participants receive placebo olfactory training kits that only contain medium chain triglycerides that lack any discernible odor

Participants receive treatment olfactory training kits that contain essential oils that have scents (lavender, lemon, clove, eucalyptus)

Participants perform olfactory training using sticks filled with unscented medium chain triglycerides.

Olfactory function as determined using the commercially available "Sniffin' Sticks" olfactory testing kit. Olfactory function is tested in three domains: threshold, discrimination, and identification. For threshold testing, the most dilute concentration of odorant that the participant is able to reliably detect is determined. In discrimination testing, the participant is evaluated on their ability to discern the unique scent among three scented sticks. In identification testing, the patient names the smells using a multiple choice form which offers four definitions for every Sniffin' stick, only one of which is correct.

Pre-operative visit (baseline), 2 weeks post-operative, 1 month post-operative, 3 months post-operative

Quality of life questionnaire. Score range 0-60, where higher score is worse and indicates more onerous symptoms.

Pre-operative visit (baseline), 2 weeks post-operative, 1 month post-operative, 3 months post-operative, 6 months post-operative

Change in Quality of Life as assessed by the ODOR (Olfactory Dysfunction Outcomes Rating) questionnaire

Quality of life questionnaire. Score range 0-112, where higher score is worse and indicates greater degree of olfactory dysfunction.

Pre-operative visit (baseline), 2 weeks post-operative, 1 month post-operative, 3 months post-operative, 6 months post-operative

Quality of life questionnaire. Score range 0-100, where higher score is better, indicative of less burden on quality of life.

Pre-operative visit (baseline), 2 weeks post-operative, 1 month post-operative, 3 months post-operative, 6 months post-operative

Quality of smell and taste as indicated on a visual analog scale. Score range 0-100, where higher score is better and indicative of better smell and taste function.

Pre-operative visit (baseline), 2 weeks post-operative, 1 month post-operative, 3 months post-operative, 6 months post-operative

Inclusion Criteria: English Speaking preoperative diagnosis of benign sellar or parasellar skull base pathology Exclusion Criteria: preoperative diagnosis of malignant sellar or parasellar skull base pathology history of endoscopic sinus surgery history of skull base surgery history of radiation therapy or other local treatments for the management of facial, sinonasal, or cranial pathologies history of chronic rhinosinusitis history of neurocognitive disorder history of intrinsic chemosensory pathology history of cardiac pacemaker history of gastrectomy