Comment on “Nomogram to Predict the Risk of External Auditory Canal Stenosis After Endoscopic Surgery: A Retrospective Study”

Dear Editor,

We read with keen interest the study by Yao et al, which presents a nomogram-based prediction model for external auditory canal stenosis (EACS) following endoscopic surgery. ¹ Their effort to integrate clinical and biochemical risk variables into a multivariate predictive framework is commendable. However, the study leaves several critical areas underexplored, warranting caution in the clinical application of the proposed tool.

First, the study relies on retrospective data and dichotomization of continuous variables such as triglycerides (TG) and systemic inflammatory indices. While this approach improves interpretability, it may significantly reduce statistical power and ignore important dose-response relationships. ² For instance, the arbitrary thresholding of systemic inflammatory response index (SIRI) and TG using receiver operating characteristic (ROC)-derived cutoffs limits the ability to model incremental risk changes and could lead to misclassification bias in borderline cases.

Second, the definition of postoperative EACS based solely on isthmus diameter (<4 mm) using ImageJ software raises concerns. Without preoperative imaging or standardized intraoperative measurements, attributing canal narrowing to the index surgery risks misclassification. ³ Although the authors mention that patients with prior EACS were excluded, intraoperative variability in bony canal shaping or stent usage could still confound the diagnosis of new-onset stenosis. Furthermore, no inter-rater reliability assessment of EAC measurements was conducted, which could affect the consistency of diagnostic classification.

Third, the study identifies hypertriglyceridemia and elevated SIRI as independent risk factors, implying a mechanistic link between dyslipidemia, inflammation, and fibrosis. However, this remains speculative in the absence of longitudinal lipid profile changes or histopathological validation. The correlation between TG and fibrotic markers is supported by indirect evidence and extrapolated from cardiovascular and orthopedic literature. No serum cytokine levels (eg, IL-6, TNF-α) or fibrosis biomarkers were measured to substantiate this pathophysiological link in the otologic context.

In addition, while the nomogram achieved strong area under the curve (AUC) values (0.89 training, 0.88 testing), the calibration and clinical utility analyses (decision curve analysis [DCA] and clinical impact curves [CIC]) would benefit from external validation in an independent, prospective cohort. The study’s reliance on a single surgeon’s operative data limits generalizability, particularly given the operator-dependent nature of endoscopic ear surgery. Moreover, the proposed interventions for high-risk patients—such as postoperative stenting—were not assessed for feasibility or effectiveness within the study framework.

In summary, while the nomogram demonstrates promising predictive accuracy, limitations in design, measurement validity, and unaddressed confounding factors restrict its immediate clinical utility. Future prospective multicenter studies with pre- and postoperative imaging, histologic validation, and intervention analysis are essential to confirm its predictive and translational value.

Rachana Mehta, MScClinical Microbiology, RDC, Manav Rachna International Institute of Research and Studies, Faridabad, Haryana, India Ranjana Sah, MDDepartment of Paediatrics, Dr D. Y. Patil Medical College Hospital and Research Centre, Dr D. Y. Patil Vidyapeeth (Deemed-to-Be-University), Pimpri, Pune, Maharashtra, India Department of Public Health Dentistry, Dr D. Y. Patil Dental College Hospital and Research Centre, Dr D. Y. Patil Vidyapeeth (Deemed-to-Be-University), Pimpri, Pune, Maharashtra, India