The Morphology Observation of Posterior Cricoarytenoid Muscle Myofiber in Patients with Idiopathic Vocal Fold Paralysis / 听力学及言语疾病杂志

Objective To investigate the morphology change of posterior cricoarytenoid muscle myofiber in patients with idiopathic vocal fold paralysis and to provide experimental evidence for the clinical treatment of idio‐pathic vocal cord paralysis .Methods Thirty -nine cases of vocal fold paralysis patients were recruited into and di‐vided into 2 groups :idiopathic vocal cord paralysis group(n=16) ,and traumatic vocal cord paralysis group(n=23) . Both groups were further divided into 3 subgroups:0 .5~1 year(5 cases and 7 cases) ,>1~2 years(5 cases and 10 cases) ,>2 years(6 cases and 6 cases) .Part of posterior cricoarytenoid muscle(PCAM ) were acquired from all of vo‐cal cord paralysis patients .Normal human posterior cricoarytenoid muscles were treated as the control group (n=5) . They were all stained with Masson three-color staining ,the fiber crosssectional area of muscle tissue and collagen connective tissue were quantitatively analyzed with the image pro plus analysis system .Differences of two observa‐tion indexes were compared with each other among groups and subgroups .Results The number of myofibers was decreased ,but the numbers of the collagen fibers was increased with the onset time course extension ,the ratio of cross sectional area of myofibers to those of collagen fibers was progressively decreasd with increased time course of denervation and more decrease within 1 year .There was obvious difference between the control group and 0 .5~1 year ,>1~2 years ,>2 years subgroup of idiopathic vocal cord paralysis (P1~2 years subgroup and >2 years subgroup ,the trend of shrinking still existed .Com‐pared two observation indexes of traumatic vocal cord paralysis with the same period subgroup indexes of idiopathic vocal fold paralysis ,there was no significant difference about these two observation indexes (P>0 .05) .In some special cases with 10 years duration in idiopathic vocal cord paralysis group ,the posterior cricoarytenoid muscle at‐rophy fibrosis was not serious .However ,in some case which the course lasted for only 1 .5 years ,the muscle atrophy was very obvious .There were great individual differences among idiopathic vocal cord paralysis patients .Conclusion If there is no recovery after half year treatment ,for PCA muscle function recovery ,the recurrent laryngeal nerve injury repair surgery could be considered to carry out within 1 year .In some cases with long disease duration (>2 years) ,they may still have the muscle morphological basis for nerve repair .

The mRNA Expression of Different Muscle Fibre Types in Denervated Rat Musculus Cricoarytenoideus Posterior / 听力学及言语疾病杂志

Objective To investigate the expression of the mRNA of muscle fibre types in the denervated post cricoarytenoid(PCA)muscle of rat.Methods Unilateral recurrent laryngeal nerve of eight rats were removed.Eight rats were used as controls.The mRNA expression of heavy chain myosin of PCA muscle fibre subtypes was measured with real-time quantitative RT-PCR in control rats and denervated rats 40 days after denervation.Results Compared to the control group,there were no significantly differences in mRNA expression of each muscle subtype between two groups.The ratio of MyHC type I to IIB was increased significantly(P=0.018).Conclusion The increased ratio of MyHC subtype I to IIB suggests the decreased contraction power of denervated PCA muscle.

EXPERIMENTAL STUDIES ON THE REINNERVATION OF POSTERIOR CRICOARYTENOID MUSCLE BY THE UPPER BRANCH OF PHRENIC NERVE / 第二军医大学学报

The purpose of this work was to reestablish the respiratory abduction of the paralyzed vocal cord through reinnervation of the posterior cricoarytenoid (PCA) muscle by partial phrenic fibres.In fifteen adult cats the adductor branch of the recurrent laryngeal nerve (RLN) of the right side was cut and its distal end ligated, while its proximal end was implanted into the PCA muscle belly.The whole RLN was then transected in the tracheo-esophageal groove and its distal stump anastomosed to the upper branch of the phrenic nerve.Direct laryngoscopy showed that the inspiratory abduction of the paralyzed vocal cord recovered within 40 d in all cats.80 d later, a larger abducent motion of the glottis was observed on the reinnervated side.Abduction was caused by reinnervation of the PCA muscle from phrenic motoneurons, as demonstrated by laryngeal electromyography and histological testings.The function of the diaphragm was preserved as revealed by monitoring of the intrathoracic pressure.