Local adjuncts to minimally invasive endoscopic interventions for benign laryngotracheal stenosis: a meta-analysis.

Background: Benign laryngotracheal stenosis is widely managed with minimally invasive endoscopic interventions, such as laser incision or excision scar, and dilation. However, various endoscopic treatments are significantly associated with a high recurrence rate. Local auxiliary measures, including inhalation of steroids, injection of steroids, and local topical application of mitomycin C, have been studied in order to increase the success rate.

Purpose: To compare the efficacy of endoscopic treatments with and without local adjuncts in patients with benign laryngotracheal stenosis, and analyze their clinical outcomes, recurrence, and complications.

Methods: In the meta-analysis, databases including PubMed, EMBASE, OVID, and Web of Science were searched for papers comparing the outcomes of adjunct therapy with non-adjunct therapy in patients with laryngotracheal stenosis. The duplicate publications, reviews, comments or letters, conference abstracts, and case reports were excluded. The random effect model was used for assessing the pooled risk estimates.

Results: Eight studies (1204 cases) referring to two prospective randomized controlled studies, two prospective cohort studies, and four retrospective cohort studies were ultimately included in the meta-analysis. Three delivery modes of adjuncts were identified, including intralesion steroid injection (n = 2), inhaled steroid (n = 2), and topical application of mitomycin C (n = 4). The decreased risk estimates of recurrence rate were detected in patients receiving endoscopic treatments with steroid injection or inhaled steroid, compared with endoscopic interventions alone (P < 0.05). Additionally, patients undergoing adjunct therapies had lower risk estimates of recurrence, compared to those receiving endoscopic procedures alone (P < 0.05), based on the subgroup of prospective cohort studies, subglottis, Mayer-Cotton scale of I-II degree, and stenosis length of < 3 cm. The high heterogeneity of the pooling risk estimates perhaps was due to factors of auxiliary drug, clinical characteristics of patients, and methodology. No discernible difference in the incidence of complication was identified.

Conclusions: Local application of steroids to minimally invasive interventions appear to reduce the recurrence rate of laryngotracheal stenosis. Various adjuncts available, including steroids and mitomycin C, appear to be safe and associated with a low risk estimate of adjuncts-specific complication rate. High quality multi-center randomized controlled studies are needed, with sufficient periods for follow-up and subjective and objective outcome indicators, to properly evaluate the efficacy, safety, and cost-effectiveness of adjuvant drugs.