Assessment and diagnostic methods of internal nasal valve: Systematic review and meta-analysis

Background: Accurate methods are needed to evaluate the anatomy of the internal nasal valve (INV), yet there is currently no ideal measurement technique. Our systematic review aims to establish a comprehensive INV assessment tool, compare different INV diagnostic tools, and establish the most ideal measurement technique for the evaluation of the INV. Methods: A systematic review and meta-analysis were conducted following the PRISMA guidelines, and the study was recorded in PROSPERO under reference number CRD42023407950. A systematic search was performed in PubMed, MEDLINE, The Cochrane Library (Cochrane Databases of Systematic Reviews), and the Cochrane Register of Controlled Trials (CENTRAL) for studies assessing INV that were conducted between 1996 and 2023. Result: Of the 421 total database searches, 23 studies were found, covering a total of 974 patients (6 studies assessed the accuracy of different diagnostic methods, with 2 of these studies comparing two different diagnostic modalities, and 17 studies measured INV angle). Based on the STROBE tool for quality appraisal the mean score was 16.92 ± ± 2.29, indicating a moderate quality. When comparing INV angle values from preoperative and postoperative records as obtained from CT readings, results showed no significant differences between the pre- and postoperative values (MD = -1.8, 95% CI, -4.8 to 1.2, p = .227). Conclusion: Acoustic rhinometry has the highest accuracy, followed by rhinomanometry then CT scan then endoscopy. Meta-analysis showed no significant differences between the pre- and postoperative values and a significant heterogeneity in the reported INV angle values across studies.