Olfactory Function and Surgery of the Lateral Nasal Wall - Systematic Review

This study aimed to comprehend the influence of surgery on the lateral nasal wall, primarily focusing on the inferior turbinates, and its impact on olfactory function. A systematic review was carried out utilizing electronic databases like PubMed, Cochrane (including various registers and databases), and Web of Science. No restrictions were imposed on publication year or language. The PRISMA criteria guided study selection, and predefined inclusion and exclusion criteria were employed. Risk of bias assessment for randomized controlled trials (RCTs) utilized the "Revised Cochrane risk-of-bias tool for randomized trials (RoB 2)," while Hawker et al. scale evaluated the quality of non-RCT studies. The review encompassed nine studies after rigorous selection and bias assessment. All studies unanimously demonstrated improved olfactory function following surgery on the inferior turbinate. Different surgical techniques and olfactory assessment methods were employed across studies. Evaluation encompassed pre- and post-surgery olfactory measurements. Most studies employed the Visual Analogue Scale (VAS) and commercial smell test kits (like Sniffin' Stick Test). The Nasal Obstruction Symptom Evaluation (NOSE) scale was used in two studies, and the butanol threshold test in one. Olfactory improvement was measured through enhanced patient numbers or nasal cavities, often expressed via VAS scores. One study utilized both patient count and VAS scores. A few studies also employed NOSE scale and olfactory threshold measurements. All studies consistently concluded that olfactory function post-surgery was superior to preoperative measures. The collective evidence strongly suggests that surgery on inferior turbinates has a positive impact on olfactory function, as indicated by the studies reviewed. Nonetheless, for a comprehensive understanding of surgical efficacy, future research should incorporate randomized controlled trials featuring control groups. This would facilitate the establishment of optimal surgical techniques for specific indications and the formulation of practical guidelines.