Long-Term Outcomes of Orthonasal, Retronasal Olfactory and Gustatory Functions in Patients Undergoing Surgery for...

This study aimed to evaluate the long-term effects of upper airway surgery on olfactory (orthonasal and retronasal) and gustatory functions in patients with obstructive sleep apnoea syndrome (OSAS). Sensory outcomes were compared between surgically treated patients and newly diagnosed OSAS patients who had not received surgery or Positive Airway Pressure (PAP) therapy. In addition, the influence of surgical technique on investigated parameters was analyzed.

This prospective study included 49 patients aged 18-75 years with OSAS, divided into a surgical group (n = 25) and a control group (n = 24). The surgical group had undergone at least one of the following procedures more than 1 year prior: anterior palatoplasty, expansion sphincter pharyngoplasty, lateral pharyngoplasty, tongue base coblation, or epiglottopexy. Orthonasal olfaction was assessed using the Connecticut Chemosensory Clinical Research Centre (CCCRC) test; retronasal olfaction using a validated 20-item powder-based test; and gustatory function with taste strips for sweet, salty, sour, and bitter.

There were no significant differences between the surgery and control groups in terms of age, apnoea-hypopnoea index (AHI), retronasal olfactory scores, orthonasal threshold, identification, mean CCCRC scores, or gustatory scores (p = 0.218, 0.912, 0.464, 0.111, 0.952, 0.423, and 0.738, respectively). In contrast, a strong and statistically significant correlation was found between retronasal and mean CCCRC scores (Spearman's r = 0.653, p < 0.001).

Upper airway surgery does not appear to adversely affect long-term olfactory or gustatory function in OSAS patients. The high correlation between orthonasal and retronasal scores supports their combined use in sensory evaluation. These findings suggest that surgery is safe with regard to smell and taste perception.