Histological Study Of Extralarynx Muscles With Similar Eletromyography Characteristics Of The Posterior Cricoarytenoid Muscle And The Lateral Cricoarytenoid Muscle

Objective : Larynx plays a critical buffering role in the balance between the surrounding environment and the internal environment.Intrinsic laryngeal muscles are responsible for diverse function including breathing,swallowing,and vocalization.Laryngeal cancer is one of the common malignant tumors in head and neck cancer.There are varying degrees of impairment in multiple functions,such as swallowing,breathing,and vocalization occurred in the patients with laryngeal surgery,radiotherapy and /or chemotherapy.In order to recover and rebuild the larynx function,laryngeal transplantation and vocal cord reconstruction by sternohyoid muscle flap have already been studied and applied in research and clinical setting.The electrophysiological characteristics of the internal laryngeal muscle,the superior hyoid muscles,and inferior hyoid muscles have been clarified.Mylohyoid muscle,thyrohyoid muscle,and lateral cricoarytenoid muscle have similar electrophysiological characteristics.Geniohyoid muscle,Sternothyroid muscle,and the posterior cricoarytenoid muscle present similar electrophysiological features.In this paper,the differences of histomorphology between the internal laryngeal muscle and the hyoid muscle(superior and inferior)have been explored,which would provide a potential and feasible surgical approach for the reconstruction of the new glottis.Methods: Use 10 healthy adult dogs,5 males and 5 males,with an average weight of 11.86 Kg.Take posterior cricoarytenoid muscle as the intrinsic laryngeal abductor,lateral cricoarytenoid muscle as intrinsic laryngeal adductor;mylohyoid muscle and geniohyoid muscle as suprahyoid muscles;thyrohyoid muscle and sternothyoid muscle as infrahyoid muscles.In this study,samples were divided into two categories: 1)lateral cricoarytenoid muscle replacement group: mylohyoid muscle,thyrohyoid muscle,and lateral cricoarytenoid muscle;2)posterior cricoarytenoid muscle replacement group: geniohyoid muscle,sternothyoid muscle,and posterior cricoarytenoid muscle.The two groups analyzed by Hematoxylin-eosin staining,Masson’s trichrome stain,and ELISA,The image analysis system quantitatively analyzed the differences of muscle fiber cross-sectional area,collagen fiber cross-sectional area,muscle fiber cross-sectional area/collagen fiber cross-sectional area and muscle fiber diameter between the arytenoid lateral muscle replacement group and the arytenoid posterior muscle replacement group.Results: 1.lateral cricoarytenoid muscle group: there is a significant difference(p<0.05)in the muscle fiber cross-sectional area(CSA),collagen fibrils CSA,the ratio of muscle fiber CSA and collagen fiber CSA,and myofiber diameter of these three types of muscles.There is no signifcicant difference in the concentration of MHC between the Mylohyoid muscle and the Lateral cricoarytenoid muscle(P=0.950);The difference in the concentration of MHC between the Thyrohyoid muscle and the Lateral cricoarytenoid muscle(P<0.05)2.posterior cricoarytenoid muscle: in the comparison of muscle fiber CSA and muscle fiber diameter,there is no significant difference between sternohyoid muscle and posterior cricoarytenoid muscle.(muscle fiber CSA P =0.754,diameter P= 0.531).The other two parameters are significantly different between these two groups(P<0.05).Conclusion: in the Lateral cricoarytenoid muscle group,the differences of histomorphology are significantly different among Mylohyoid muscle and the Lateral cricoarytenoid muscle;there have differences in histological characteristics and the concetration of MHC between the Thyrohyoid muscle and the Lateral cricoarytenoid muscle;.In the posterior cricoarytenoid muscle,Geniohyoid muscle is significantly different from the Posterior cricoarytenoid muscle;There is no enough evidence to approve that the sternothyroid muscle is significantly different from posterior cricoarytenoid muscle.