Safety of human olfactory mucosal biopsy for the purpose of olfactory ensheathing cell harvest and nerve repair: a prospective controlled study in patients undergoing endoscopic sinus surgery

Background: Nasal olfactory mucosa is an accessible source of olfactory ensheathing cells for spinal cord regeneration. However, safety of the biopsy technique and the effects on sense of smell and nasal function have not been robustly assessed in the form of a prospective controlled study. Methodology: National Health Service ethical approval was granted for this study of 131 patients. The primary outcome measure was olfactory function and the secondary outcomes included postoperative complication rates as well as the SNOT 22, NOSE scale scores and surgeon reported (Lund-Kennedy score) nasal function outcomes. Results: 65 patients underwent functional endoscopic sinus surgery (FESS) and superior turbinate biopsy, and 66 patients underwent FESS only as the control group. There was no significant difference in complication rates between the two groups. All Olfactory function outcomes were unaffected following olfactory biopsy. We demonstrated that the patient's quality of life and nasal patency as well as surgeon reported outcome measurements remain unaffected following olfactory harvesting. Conclusions: We have uniquely provided level 2a evidence for the safety of endoscopic biopsy of olfactory mucosa, which does not affect nasal function or the sense of smell compared to standard FESS without biopsy.