Effect of partial cricotracheal resection and extended cricotracheal resection for severe laryngotracheal stenosis / 中华耳鼻咽喉头颈外科杂志

To assess the outcomes of partial cricotracheal resection (CTR) and extended cricotracheal resection (ECTR) for severe laryngotracheal stenosis. From November 2009 to September 2017, 18 patients underwent CTR and ECTR at the Department of Otorhinolaryngology Head and Neck Surgery, Tangdu Hospital, Air Force Medical University for severe laryngotracheal stenosis were reviewed retrospectively. There were 12-male and 6-female patients, with the age ranged from 4 to 56 years (median 25 years). The causes were postintubation in 11 cases, cervical trauma in 4, idiopathic in 3. The stenosis located in subglottic and tracheal (12), glottic and subglottic and tracheal (3), subglottic (2), and glottic and subglottic (1). Two patients had concurrent unilateral vocal cord palsy.One patient had undergone previous endoscopic balloon dilation and 8 patients had previous laryngotracheal reconstruction. The stenosis was graded according to modified Myer-Cotton classification as follows: Ⅲb (1), Ⅲc(1), Ⅳa (2), Ⅳb (12), Ⅳc (2). The surgical outcomes and complications were recorded. Among 18 patients,11 of the 12 patients undergoing CTR were decannulated. Five of the 6 patients undergoing ECTR were decannulated. Resected airway length ranged from 1.5 to 4.0 cm (median 2.8 cm). Surgical complications included infection of incision wound in 2 cases, anastomotic granulation in 2, cervical subcutaneous emphysema in 1, aspiration in 1, and unilateral arytenoid prolapse in 1. No recurrent laryngeal nerve injury or tracheoesophageal fistula occurred. The median follow up was 11 months. CTR is efficient for severe subglottic and upper tracheal stenosis while ECTR is efficient for subglottic stenosis extended to the glottis. Both procedures also provide a salvage therapy for patients with previous failed treatments.

Study on decellularized laryngeal scaffold in dogs / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To explore the survivorship and character of decellularized laryngeal scaffold in pectoralis major muscle flap in canine.</p><p><b>METHODS</b>Eighteen donor larynx in experimental group were decellularized by perfusing sodium dodecyl sulphate. Three of them were used to detect the character of histology. The other fifteen ones were embedded in right pectoralis major muscle flap of acceptor canine. Donor larynx in control group were not perfused. Other experimental procedure was the same as experimental group. The specimens were harvested at two weeks, one month and two months after operation, respectively. Macroscopic view, histological examination and trypan blue staining were performed in the experimental group and control group.</p><p><b>RESULTS</b>The size of the specimens decreased remarkably into disappearance in control group, there was statistical significance between the experimental group and the control group (which used least significant difference t test P < 0.05). There was only little neutrophils and lymphocytes infiltrating around the laryngeal scaffold at 2 weeks in the experimental group. One month after operation, loose connective tissue begin to form around the laryngeal scaffold. After two months of transplantation, the connective tissue became thicker and the number of blood vessels increased than before. There was a large number of lymphocytes and neutrophil infiltration around the laryngeal specimens in the control group at 2nd week. The perichondrium in the control group was damaged at one month post operation. The cartilage cells could not be detected two months after surgery. The survival rate of cartilage cell between experimental group (86.8% ± 3.2%) and the control group (88.6% ± 3.1%) did not show statistical significance before implantation (χ(2) = 0.19, P > 0.05). The survival rate of cartilage cell decreased insignificantly in experimental group while the survival rate declined obviously in the control group at two weeks and one month after operation, the difference had statistical significance (χ(2) were respectively 5.52 and 20.55, P were respectively < 0.05 and < 0.01), the survival rate of cartilage cell in experimental group was (65.8% ± 2.6%) at two months after operation, while the cartilage cell all disappeared in control group.</p><p><b>CONCLUSIONS</b>Perfused decellularation technique can construct a low immunogenicity laryngeal cartilage scaffold which can survive in the chest muscle package and establish a good blood supplement. The decellularized laryngeal scaffold could be used as a biological scaffold for whole laryngeal reconstruction.</p>

Biomechanical study on decellularized laryngeal scaffold in dogs / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To evaluate the biomechanical characteristics of the decellularized laryngeal scaffold.</p><p><b>METHODS</b>Ten Chinese adult dogs were randomly divided into two groups: perfusion group (n = 5) and control group (n = 5). The acellular larynx scaffold was obtained from dogs through cranial thyroid arteries perfusion with detergents. Comparative examinations were performed by the macroscopic view, histological view (hematoxylin and eosin stain, Alcian blue stain and Masson stain), scanning electron microscope (SEM) and biomechanical properties between perfusion group and control group.</p><p><b>RESULTS</b>Macroscopic view showed that the decellularized laryngeal scaffold appeared pale asphyxia. HE stain indicated that there were little acellular traces of muscle and mucosa. Alcian blue stain, Masson stain and scanning electron microscope (SEM) suggested that there were no obvious changes about glycosaminoglycan and collagen. The compressive modulus of thyroid cartilage was (1.06 ± 0.07) MPa (x(-) ± s) in experimental groups and (1.15 ± 0.11) MPa in control group, showing no significant difference (t = 1.424, P > 0.05), neither in compressive modulus of annular cartilage (1.68 ± 0.11) MPa in experimental groups and (1.67 ± 0.09) MPa in control group (t = 0.185, P > 0.05). The tensile strength of thyroid cartilage between experimental (5.74 ± 0.88) MPa and control groups (6.18 ± 1.33) MPa did not have the statistical significance (t = 0.627, P > 0.05).</p><p><b>CONCLUSION</b>These results indicate that perfusion method can construct a perfect biomechanical acellular larynx scaffold which could be a better selection for laryngeal reconstruction with tissue engineering method.</p>

Immunological study on decellularized whole laryngeal scaffold / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To evaluate the immunogenicity of the decellularized laryngeal scaffold.</p><p><b>METHODS</b>Twelve perfused, decellularized laryngeal scaffolds were obtained from rabbits through common carotid artery perfusion with detergents. The twelve decellularized laryngeal scaffolds and the twelve fresh larynxes were then implanted in para-laryngeal muscles of rabbits and harvested after two weeks, four weeks, twelve weeks and twenty-four weeks, respectively. Macroscopic view, histological examination and lymphocyte infiltration test were performed.</p><p><b>RESULTS</b>The decellularized larynxes were implanted and preserved the laryngeal extracellular matrix and laryngeal architecture. The decellularized larynx did not show obvious immunological rejection after implanted into the para-laryngeal muscles of the recipient rabbits. The volume of implanted larynx became smaller but retained cartilage scaffold. The larynxes in the control group presented the serious immunological rejection and the majority tissues of the larynxes were disintegrated and substituted by the fibrous connective tissues after four weeks. The peripheral tissues were damaged and necrotic at different degrees. The quantity of the lymphocyte infiltration in the control group was higher than that in the experiment group and the result had the statistical significance (P < 0.01).</p><p><b>CONCLUSIONS</b>Perfused, decellularized technique can construct a low immune laryngeal cartilage scaffold which could be a satisfactory material for laryngeal repair.</p>

A preliminary study on the preparation of perfusion-decellularized laryngeal scaffold and the feasibility of laryngeal muscle reconstruction / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To prepare a decellularized whole laryngeal scaffold by utilizing a perfusion-decellularized technique, reseed cells on it, and construct decellularized laryngeal muscles.</p><p><b>METHODS</b>Perfusion decellularized larynxes were obtained by common carotid arterious perfusion with detergents. Then they were performed by macroscopic view, histological examination, scanning electron microscopy (SEM) and cartilage viability. Decellularized laryngeal scaffold were then reseeded with inducted mesenchymal stem cells (MSCs). Composites were transferred into greater omentums of rabbits after one day's adherence and harvested after eight weeks. Macroscopic view, histological examination and immunohistochemistry were performed.</p><p><b>RESULTS</b>Perfusion larynxes became transparent after two hours. Histology and SEM indicated that perfusion method showed better decullularized effect. More vintages and collagen fibers but no intact cell or nuclei were retained in the decellularized matrix. Porosity measured by Image pro plus 6.0 was 80.4% +/- 3.2% (x +/- s). Chondrocyte vitality assay indicated chondrocyte vitality rate in the perfusion group was 86.9% +/- 1.5%. After eight weeks, vascularization formed and integrated cartilage frameworks still remained. Histological examination could clearly show the presence of muscle bundles and vessels. Immunohistochemical examination indicated that sarcomeric-alpha actin expressed positively in corresponding areas.</p><p><b>CONCLUSIONS</b>It is feasible to reseed MSCs into the decellularized laryngeal muscle matrix for constructing tissue-engineered laryngeal muscles. This in vivo maturation into the omentum could be the first step before in situ implantation of the construct.</p>

Experimental study on tracheal reconstruction using porous titanium rings and free skin flap / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the feasibility and efficacy of the cervical tracheal reconstruction using porous titanium rings and free skin flap.</p><p><b>METHODS</b>Twelve adult mongrel dogs were divided randomly into group I and group lI. A segment of cervical trachea (25 mm, 4 rings, about 2/3 circumference) was resected and a rectangular free skin flap was harvested from abdomen. The flap was sutured to the defect part and supported with two porous titanium rings (group I) or without (group II ). X ray and fiberscopic examinations were performed at the end of the first and the sixth months postoperatively. After six months the dogs were sacrificed and the grafts were examined macroscopically and microscopically.</p><p><b>RESULTS</b>In group I, one dog was sacrificed for wound infection and skin flap necrosis with deflexion of titanium rings in the fifth day postoperatively. The other 5 of 6 survived until the end of six months. X-ray examination showed titanium rings were fastened well without displacement or deformity. Through fiberscopy, the trachea luminal patency was maintained well without stricture, shrinkage or necrosis. Histologic examination showed most of the inner surface of the flap was covered with ciliated columnar epithelium. In group II, 3 of 6 dogs died of suffocation within 24 hours postoperatively. The remaining 3 dogs survived from 7 to 16 days with dyspnea and fiberscopic examination showed narrowed trachea lumens.</p><p><b>CONCLUSIONS</b>Porous titanium rings could recreate the framework for cervical tracheal reconstruction using free skin flap and would be one of the options for tracheal reconstruction.</p>