INTRODUCTION
Vocal cord polyps are one of the most common diseases that cause hoarseness. They are lesions of the larynx that are second only to the vocal cord nodules. Vocal cord polys are the most common laryngeal proliferative lesions as well. They are the products of voice overuse, misuse and abuse. However, vocal cord polys can also be caused from a traumatic vocal cord injury.1,2 Vocal cord polyps are typically unilateral benign lesions, most of which are located at the edge of the anterior 2/3 of vocal folds and can be classified as pedunculated or sessile.3,4 The vocal folds are made up of three major layers from superficial to deep: the epithelium or epithelial tissue, the lamina propria and the vocalis muscle. The most superficial layer is the epithelial layer of the squamous epithelium. The middle section is lamina propria which consists of three layers referred to as superficial, intermediate and deep layers. The superficial layer of the lamina propria is a jelly-like material made up pf elastin and interstitial fluid. The intermediate layer is made up of elastin and the deep layer is mostly collagen, and together they form the vocal ligament. The thyroarytenoid muscle is the deepest layer of the vocal folds and is a muscle which is related to activating chest voice.5
Mechanical vibrations produce strong force during the vocal fold movement, which may lead to vasodilatation of the submucosa of the vocal folds, increased permeability of the vascular wall, and edema.6 The basic lesions occur in the lamina propria and accompanied by vascular changes. The major features of pathological characteristics of vocal fold polyps are increased swelling, inflammation and vascular lesions in the lamina propria layer.7,8 The histological features of vocal cord polys are characterized by their appearances (gelatinous or translucent), fibrous tissue proliferation, and vascular changes (hemangioma-like changes or hemorrhages). The typical pathological changes include diffuse or localized edema, fibrosis, dilated blood vessels, and degeneration of hyaline and basophils in the lamina propria.6,9 Although some small and hemorrhagic vocal cord polyps may recover spontaneously or with conservative treatment, the vast majority of vocal cord polyps require surgical treatment, especially sessile vocal cord polyps.10,11
Surgical management of vocal cord polyps usually includes microlaryngoscopic surgery, electronic flexible laryngoscopic surgery, rigid laryngoscopic surgery, etc. Microlaryngoscopic surgery is mostly performed under general anesthesia at hospital. Electronic flexible laryngoscopic and rigid laryngoscopic surgery can be performed under local anesthesia in an outpatient setting, which have more advantages in the simplicity of treatment.12,13Sessile polyps are less effective and more difficult to treat by surgery than pedunculated polys. Meanwhile, the effectiveness of treatment varies depending on the various histological features of vocal cord polyps. To the best of our knowledge, there is no report on the evaluation of the effectiveness of surgical performance for different histopathological types of vocal cord polyps. Based on the differences of clinical features and histopathological characteristics, we retrospectively analyzed the clinical efficacy of transnasal electronic flexible laryngoscopic vocal fold polypectomy and transoral microlaryngoscopy in the treatment of broad-based sessile vocal cord polyps.