| Objective: Laryngeal carcinoma is one of the common malignant tumors in head and neck region. Total laryngectomy still has its irreplaceable position as a treatment for advanced laryngeal and hypopharyngeal carcinoma which is the most basic and most safety procedure.Phonation function was lost permanently after total laryngectomy. There have been a lot of ways to rehabilitate phonation at home and abroad. But an ideal method that reconstruct breathing, swallowing and pronunciation all three functions at the same stage has not yet appeared so far-This study is to study synchronous electromyograhic features of suprahyoid muscles(anterior digastric muscle AD, posterior digastric muscle PD, stylohyoid muscle SHM, mylohyoid muscle MH and geniohyoid muscle GH) , infrahyoid muscles (sternohyoid muscle SH, sternothyoid muscle ST, thyrohyoid muscle TH, ) and intrinsic laryngeal muscles (lateral cricoarytenoid muscle LCA, and posterior cricoarytenoid muscle PCA) under the circumstances of eupnea, deep breath, swallowing and phonation. Select the exterior laryngeal muscles whose myoelectric feathers are similar to lateral cricoarytenoid muscle or posterior cricoarytenoid muscle. In this animal experiment,hyoid bone and exterior laryngeal muscles which myoelectric feathers are similar to lateral cricoarytenoid muscle or posterior cricoarytenoid muscle were used to reconstructe the structure and function of larynx and discuss the reconstruction method of I period after total laryngectomy.Methods: The study including three parts. Part one: electromyograhic studies of suprahyoid muscles and infrahyoid muscles in dogs. Part two: new glottic reconstruction after total laryngectomy: animal experiment, anesthesia and preoperative care. Part three: anesthesia for total laryngectomy and neo-glottic reconstruction on experimental dogs. The methods of part one: synchronous electromyograhic features of 13 dogs were observed under the circumstances of eupnea, deep breath, swallowing and phonation, including of time taken in advance of myoelectricity , peak amplitude, contraction activity lasting,amplitude of action potential, action potential duration. Compare synchronous electromyograhic features of suprahyoid muscles to infrahyoid muscles in 5 dogs randomized.The relation of myoelectricity of laryngeal muscle and laryngeal function was analyzed as well. The methods of part two: in early experiments, 13 adult dogs underwent total laryngectomy plus tracheostomy in order to investigate perioperative nursing and rearing. A comparative study was carried out between two kinds of anesthesia to explore a proper anesthesia for total laryngectomy and neo-glottic reconstruction on experimental dogs.After stable anesthesia, skilled care and feeding were possessed, total laryngectomy plus neo-glottic reconstruction started: 7 adult dogs underwent low order tracheotomy and total laryngectomy. Then trachea - pharyngeal anastomosis was formed as a new glottis preliminary.The new abductor, adductor were respectively made of hyoid muscles and pharyngeal constrictor muscles to open and close the glottis.A conventional postoperative care was implemented after surgery. The methods of part three: Thirteen adult dogs undergoing total laryngectomy and neo-glottic reconstruction were randomly divided into two groups. First dosage: Group A:3% pentobarbital sodium (1ml/kg, intraperitoneal injection). Group B: 5% pentobarbital sodium (0.25ml/kg, im) combined with sumianxin? (0.05ml/kg, im).Results: The results of part one:? AD, PD, STH, MH, GH, SH,ST and PCA discharge during inspiratory phase, while TH and LCA discharges during expiratory phase. All the above muscles have a reinforced discharge in condition of deep breath. During the inspiratory phase GH is synchronized with PCA, and the wave shape, amplitude timing and intensity of myoelectricity of GH are similar to those of PCA respectively, and TH is synchronized with LCA during the expiratory phase.?during swallowing,AD, PD,STH,ME,GH,TH and LCA show an intensive synchronous discharge.The myoelectricity of PCA is suppressed while myopotential can be detected during intermission. GH and STH show obsolete myoelectricity activities. During swallowing MH, GH and TH are synchronized with PCA; and the wave shape, amplitude timing and intensity of MH, GH and TH are similar to those of PCA respectively.?during phonation, AD, PD, SH, ST, TH and PCA show an intensive synchronous discharge, while emergence time of PCA is 400-460ms later than that of LCA,and with a lower amplitude. GH and STH show obsolete myoelectricity activities. During phonation MH and TH are synchronized with LCA; and the wave shape, amplitude timing and intensity of MH and TH are similar to those of posterior lateral cricoarytenoid muscle respectively. The results of part two:all dogs survived after surgery, minimum survival time: 14 days; maximum: 67 days; average: 27days. Most dogs died from airway obstruction and asphyxia which due to the incomplete displacement of the tracheostomy tube. One died from premature detubation. One had no explainable cause of death.?Swallowing recovery: all 7 cases (7/7) resumed oral intake. five cases reached?° or ?° swallowing in 6 ?10 days after surgery. The remaining 2 cases used to be ?° or ?° in early days after surgery. The two respectively reached ?°in 21th and 22th days by deglutition training. ?Phonation recovery: 4 (4/7)rehabilitated phonation. Three of them phonated with a howl for the first time in 9th after surgery while tube-plugging, sound like"ha ha", low and thick. Hearing distance: one: 15 metres; the other two: 6 metres. One case could not phonate while tube-plugging after surgery because of mild dyspnea. Granulation blockage in neoglottis was found in 20th after surgery and then was removed.Phonation was recorded the next day. Hearing distance: 11 metres. The remaining three cases suffered breathing obstruction, vomiting, so phonation could not be induced.? Respiration recovery: 4(4/7) rehabilitated nasal respiration while plugging tracheostoma, and one got postoperative decannulation. Plugging was tried from the ninth day after surgery. Four cases could keep on breathing while plugging. There were some reasons that prevent dogs from decannulation: food refusal due to severe bucking; granulation blockage recurrence in neoglottis; long-term complications of cicatricial contracture in neoglottis. One case got postoperative decannulation and survived in good health. The results of part three: GroupA:The anesthesia induction time was on the average 19.7±6.2min.The maintenance of first anesthesia time was 119.6±34.6min.It needed several more injections to keep anesthesia during the surgery and had poor postoperative recovery. GroupB:Induction time was 5.5±1.8min,the maintenance of anesthesia time was 112.5±24.3min for the first.Only adding one more injection (1/2first dose)during the surgery,the maintenance of anesthesia time was prolonged to at least 169.8±20.2min. The dogs reanimated soon after operation.Conclusions:1. During swallowing and phonation MH is synchronized with LCA; and the wave shape, amplitude timing and intensity of myoelectricity of MH are similar to those of LCA respectively. MH can be chosen as the backup muscle for the reestablishment of glottic adducent function.2. During the expiratory phase, swallowing and phonation TH is synchronized with LCA; and the wave shape, amplitude timing and intensity of myoelectricity of TH are similar to those of LCA respectively. TH can be chosen as the backup muscle for the reestablishment of glottic adducent function.3. During the inspiratory phase GH and ST are synchronized with PCA, and the wave shape, amplitude timing and intensity of myoelectricity of GH and ST are similar to those of PCA respectively, so GH and ST can be chosen as the backup muscles for the reestablishment of vocal cord abducens function.4. After total laryngectomy, a larynx frame and new functional glottis with functions of open and close was reconstruct using hyoid bone, cartilage trachea ring,hyoid muscle and pharyngeal constrictor muscles. Most part of experiment dogs can restore the swallowing,pronunciation and respiratory.5. The new larynx reconstructed by the annulus tracheae and hyoid was not firm enough to resist the force of contracting muscles.6. The new abductor muscles replaced by infrahyoid and suprahyoid muscles with the ability to open the glottis. While the new adductor replaced by pharyngeal constrictors doesn't work well to close the glottis due to poor contraction force.7. Pentobarbital sodium combined with sumianxin anesthesia appears to be a satisfactory method to anaesthetize dogs for total laryngectomy and neo-glottic reconstruction.It can decrease induction time, reduce the time and dose of added anesthetics, and obtain a more satisfied anesthesia level and rapid recovery. |
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