Histologic study of the growth of the subglottis after interruption of the circular structure of the cricoid

In a previous study in growing rabbits it was demonstrated that after resection of a ventral part of the cricoid the lumen of the subglottic airway developed normal size during further growth up to the adult stage. Histologic investigations of these cases suggest that a subepithelial network of elastic fibres, ventrally suspended to the thyroid and the tracheal rings, ensures the airway lumen and prevents the development of a subglottic stenosis. Resection of a ventral part of the cricoid including the adjacent soft tissue lining of the airway causes an irreversible loss of the supporting elastic layer and the formation of scar tissue resulting in a stenosis. It was concluded that the larynx and trachea can be considered as an inner, elastic tube (= conus elasticus) lined with epithelium, suspended to an outer, segmented cartilaginous tube. At the level of the subglottis an intact conus elasticus is of more importance for the normal development of the airway lumen in young rabbits than an intact ventral half of the cricoid ring.     

A morphometric study of the growth of the subglottis after endolaryngeal trauma

In young rabbits the growth of the subglottis was studied over a period of 20 weeks following an endolaryngeal trauma. This lesion of the larynx at the age of 4 weeks resulted in the development of a stenosis in the adult stage. The stenosis appeared to be caused by a specific change in the pattern of growth leading up to an anterior narrowing ('pear'-like) of the cricoid ring and a conspicuous thickening of the subepithelial layer.     

A histologic study of the growth of the subglottis after endolaryngeal trauma

In young rabbits the histologic features of the growth of the subglottis were studied after an endolaryngeal trauma. This lesion of the larynx leading to a subglottic stenosis, caused specific pathologic changes of the cricoid cartilage and the subepithelial tissues. Activation of chondrocytes resulted in proliferation and regeneration of destructed cartilage. The normal subepithelial structures were replaced by granulation tissue differentiating into a thick fibrous scar and into cartilage. This ectopic cartilage together with the repaired cricoid formed a composite thickened 'ring'-like cartilaginous structure in the adult stage.     

Differential effects of endolaryngeal trauma upon the growth of the subglottis

In young rabbits (4-week-old) the growth of the subglottis was studied after an endolaryngeal soft tissue trauma. The injury induced the formation of a subglottic stenosis. In contrast to earlier observations on endolaryngeal trauma extending into the cricoid cartilage, the cricoid developed normally to the adult size and shape at 24 weeks. Similar to the earlier findings, the subepithelial layer showed considerable thickening as the result of formation of scar tissue, ectopic cartilage and fatty tissue with interruption of the elastic tunica (= conus elasticus). It was concluded that after endolaryngeal trauma in rabbits two types of subglottic stenosis can develop, determined by the depth of the injury.     

A study of endotracheal tube injury to the subglottis

An endotracheal tube presses against distinct pressure points within the airway. These areas are the shaft of the tube against the arytenoids and posterior cricoid and the cuff-tube tip in the trachea. An ulcerative injury occurs at these interfacing points from motion occurring between tube and tissue. Minimizing this inherent movement is possible by tube modification and, in the presented animal model, prevents injury.     

Rosai-Dorfman disease of the subglottis

A case of subglottic narrowing caused by an extranodal deposit of sinus histiocytosis in a 29-year-old man is reported. The characteristic features of Rosai-Dorfman disease, such as massive painless cervical lymphadenopathy, fever, raised erythrocyte sedimentation rate and raised white cell count, were all found to be absent. However, typical histological features, such as diffuse lymphoplasmacytic infiltrate, Russel bodies, foamy histiocytes and histiocytes with emperipoiesis, confirmed the diagnosis. Rosai-Dorfman disease is an uncommon disorder and its presentation with progressive subglottic narrowing is extremely rare. Our experience in the management of this condition is reported and the review of literature is discussed.     

Inflammatory pseudotumor of the subglottis

Summary A rare case of an idiopathic inflammatory pseudotumor of the larynx is described. Management consisted of midline vertical thyrotomy with anterior cricoid splitting, excision of the subglottic tumor and temporary stenting of the lumen with a siliconized tube. While these lesions are benign, the therapeutic consequences of misdiagnosis can be serious. Effective treatment consists of surgical excision, which results in a permanent cure.     

Squamous cell carcinoma of the subglottis

STUDY DESIGN: A retrospective study over a 25-year period of patients with laryngeal carcinoma treated by the Department of Otolaryngology at Wake Forest University. METHODS: The boundaries of the subglottis were defined as 5 mm below the free edge of the true vocal folds extending to the inferior border of the cricoid cartilage. All were staged according to American Joint Committee on Cancer: stages I and II were considered early and stages III and IV as late. Patients were grouped by treatment modality of surgery alone, surgery and radiotherapy, radiotherapy alone, and radiotherapy with surgical salvage. RESULTS: Fifteen patients represented 1.4% (15/1098) of laryngeal cancers diagnosed within that period. All patients had squamous cell carcinoma of the subglottis of which 20% (3/15) had early-stage disease (T1-T2) and 80% (12/15) had late-stage disease (T3-T4). Overall 3-year survival was low (25%) and is attributed to a high incidence of advanced-stage disease with a high rate of extralaryngeal spread and/or metastasis, especially to the lungs and paratracheal nodes. CONCLUSIONS: To improve earlier detection by primary care physicians and otolaryngologists and to improve treatment outcome, awareness of subglottic carcinoma and its appropriate evaluation is critical in the patient presenting with hoarseness and/or stridor. Radiation therapy treatment to include the low and upper mediastinal compartments to cover local/regional extralaryngeal involvement is advocated as well as paratracheal lymphatic neck dissection and thyroidectomy in surgically treated lesions.     

兔环状软骨裂开喉气管成形术对环状软骨生长发育的影响

目的：探讨兔环状软骨前后裂开对环状软骨生长发育的影响。方法：将兔环状软骨前后正中裂开,8个月后测量环状软骨内径,计算其管腔面积。结果：与对照组比较,实验组兔环状软骨管腔面积较对照组差异无统计学意义。结论：环状软骨裂开喉气管成形术对环状软骨的生长发育无显著影响。     

声门下型喉鳞状细胞癌的临床探讨

目的 探讨声门下型喉鳞状细胞癌(简称鳞癌)的临床特点、淋巴转移规律、治疗模式及预后相关因素.方法 回顾性分析中国医学科学院肿瘤医院头颈外科1970-2005年初治的36例声门下型喉鳞癌患者的临床资料,其中Ⅰ期6例,Ⅱ期9例,Ⅲ期8例,Ⅳ期13例.单纯放疗8例,单纯手术18例,手术加放疗10例.分析不同分期、不同治疗方式的生存情况.采用Kaplan-Meier法计算生存率,Log-Rank法作差异检验,不同组间率的比较采用卡方检验.结果 除3例患者无瘤状态下失访外,其余33例均随访5年以上或至死亡.5年生存率为58.2％,其中Ⅰ、Ⅱ、Ⅲ、Ⅳ期5年生存率分别为66.7％、66.7％、62.5％、30.8％,Ⅰ～Ⅲ期与Ⅳ期两组比较差异有统计学意义(x2=3.955,P＜0.05);单纯放疗、单纯手术、手术加放疗的5年生存率分别为43.8％、66.7％、51.9％.淋巴转移率为25.0％ (9/36),阳性淋巴结主要分布在Ⅵ区,其次为Ⅱ区.NO、N+患者的5年生存率分别为66.7％、20.8％,两组差异有统计学意义(x2 =6.466,P＜0.05).结论 声门下型喉鳞癌预后相对较差.喉全切除术是该型喉鳞癌主要的治疗方式,仅部分早期患者可行单纯放疗或喉部分切除术.局部晚期患者在手术同期应行颈部Ⅱ～Ⅳ区及Ⅵ区的淋巴清扫术.     

Microbial flora of the subglottis in intubated pediatric patients

Infection of the intubated subglottis is felt to be one of the many factors involved in the pathogenesis of acquired cicatricial subglottic stenosis. The precise role of infection is unclear and the microbial flora has not been established. An analysis of subglottic culture material, from 22 intubated pediatric patients undergoing tracheotomy, has been performed to establish the nature of the subglottic microbial flora. Fifty-nine isolates were found, including 19 types of organisms. The number of isolates per patient ranged from one to eight, with an average of 2.7 isolates per patient. The most common isolates in the 22 patients were α-hemolytic Streptococcus viridans (17 isolates-77%), Neisseria sp. (6 isolates-27%), Pseudomonas sp. (5 isolates-22%), and coagulase negative Staphylococcus sp. (5 isolates-22%). This data indicates that colonization of the subglottis in intubated pediatric patients is polymicrobial in nature. α-Hemolytic Streptococcus viridans and Neisseria sp. were most common, with a shift in cultured flora towards Pseudomonas sp. in patients intubated for more than 10 days. In view of this, antimicrobial therapy may be of benefit in preventing acquired cicatricial subglottic stenosis.     

Novel cell proliferation marker for identification of a growth center in the developing human cricoid

BACKGROUND: Developmental histomorphology of the human cricoid cartilage has never been well described. Regional growth centers in the cricoid have been hypothesized, but have never been demonstrated in histological sections. OBJECTIVES: To apply Mib-1 immunostaining, a monoclonal antibody directed at a nuclear proliferation marker, in human cricoids to identify a growth center and to study the changing histomorphology of the developing cricoid. DESIGN: Immunohistochemical Mib-1 studies were performed on postmortem cricoid sections of 2 fetuses (gestational age, 18.5 and 33 weeks), 1 newborn (full term, 41 weeks), and 3 children (aged 1, 4, and 13 years, respectively). Cell counts, surface areas, and organizational patterns of the chondrocytes were studied and described in hemotoxylin-eosin-stained sections. RESULTS: Differential Mib-1 staining was found. The 18.5-week fetus showed diffuse cell proliferation throughout the cricoid. The cricoid sections of the 33-week fetus and 1-year-old child revealed a distinct ring of proliferation in the outer third of the cricoid ring. The 4- and 13-year-old exhibited no cell proliferation. Histomorphologically, with increasing age came chondrocyte hypertrophy, decreasing cell count per standard square, and increasing organization from a scattered to radial columnar pattern. CONCLUSIONS: Growth of the cricoid involves a diffuse pattern of cell proliferation throughout the cricoid in fetal tissue. At term and until age 1 year, the region of proliferation is more restricted to the outer subperichondrial surface. By age 4 years, cell proliferation has stopped. Histomorphologic changes in the developing cricoid include decreasing cell counts per standard unit area, but increasing surface area with age. The aging chondrocytes develop an increasingly organized layout to form a radially arranged columnar pattern similar to that in the growth plate of the developing limb bud.     

Low-grade mucoepidermoid carcinoma of the subglottis treated with organ-preservation surgery

Mucoepidermoid carcinoma of the subglottis is infrequently reported in the literature. This tumor subtype is more commonly associated with the major and minor salivary glands. Mucoepidertoid carcinoma of the larynx can be difficult to diagnose, and there is no consensus as to appropriate management. We report a case of a low-grade mucoepidermoid carcinoma that was confined to the subglottis and treated with organ-preservation surgery. A conservative surgical approach was taken because of the tumor's low-grade histology and its location and in order to preserve the patient's laryngeal function. At follow-up 15 months postoperatively, the patient remained disease-free, and laryngeal function was intact.     

Morphometric and histochemical study of the human vocal muscle

The present study was conducted on vocal muscles removed at autopsy from adult individuals (10 men and 8 women, ages ranging from 48 to 78 years) with no laryngeal disease. Histologic analysis was performed with hematoxylin and eosin staining, and histochemical analysis was performed by nicotinamide-adenine-dinucleotide tetrazolium reductase, succinate dehydrogenase, and acid and alkaline myofibrillar adenosine triphosphatase reactions. The histochemical reactions showed that the muscle consists of slow-twitch oxidative (SO), fast-twitch glycolytic (FG), and fast-twitch glycolytic oxidative (FOG) fibers distributed in mosaic form. The frequencies of SO, FOG, and FG fibers were 40.50%, 54.75%, and 4.75%, respectively. The higher frequency of SO and FOG oxidative fibers characterizes the muscle as having aerobic metabolism, resistance to fatigue, and fast contraction. The mean minimum diameters were 31.37 microm for SO fibers and 36.46 microm for FOG and FG fibers.     

Carcinoma of the subglottis. Results of initial radical radiation

During the 12-year period 1971 to 1982, 23 patients with primary squamous cell carcinoma of the subglottis were treated with initial radical radiation therapy. There were 19 men and four women, with a mean age of 64 years. Five patients had T1 tumors, four had T2, three had T3, and 11 had T4. The actuarial overall and cause-specific survival rates were 26% and 61%, respectively. Local control was achieved with initial radiation therapy in 16 patients (70%). Subsequent local control was achieved in one other patient following surgery for recurrence, giving an ultimate local control figure of 74% (17 of 23 patients). All patients with T1, T2, and T3 disease achieved local control with initial treatment; however, seven of the 11 patients with T4 disease either had residual disease following radiation therapy or developed local recurrence on follow-up.     

The applied anatomy of the anterior commissure and subglottis.

The applied anatomy of the subglottis and anterior commissure is discussed and an attempt made to correlate the histological anatomy with that clinically accessible. It is suggested that although the undersurface of the vocal fold is classified as part of the glottis by the 1972 UICC and AJC staging system, it should be considered as the roof of the subglottis. The anterior commissure, which is probably a small site within the glottis rather than a true area, is histologically difficult to separate from the anterior subglottis. The characteristic microvasculature of the anterior commissure is presented as being possibly relevant to the mode of spread of tumors at this site.     

Morphology of the human larynx. II. The subglottis

The macroscopic staining method was used to display and measure the epithelium of the human subglottic space. Small islands of squamous metaplasia were found in about 40% of the non-smoking, non-bronchitic urban population. There was no age or sex difference, although a highly significant decrease in size of the subglottic space was found in women throughout life.