The endoscopic approach to the neck: a review of the literature, and overview of the various techniques.

BACKGROUND: The endoscopic surgical approach to the neck has reached the head and neck surgeons' view with a certain delay, compared to other fields of endoscopic procedures. This may be attributed to the tight work space and plenty of vital structures in the operating field. Since study groups described first attempts with endoscopic or video assisted removals of thyroid glands in the late nineties, selective neck dissections on animal models or cadaveric dissections were performed in 2003. METHOD: The review consists of a Medline Search regarding the terms of endoscopic, video- assisted neck dissections, excision of neck lesions, thyroidectomy and submandibular resection and minimal access surgery. The three main procedures (selective neck dissection, submandibular resection and thyroidectomy) are described and reviewed in the following test. RESULTS: Various techniques have been performed successfully and led to good clinical results. The studies described in literature other than for thyroidectomy often do not exceed the level of small series or case-reports. CONCLUSION: With a good proof of indication gasless lifting techniques, video assisted endoscopical techniques and subcutaneous approaches with gas filling procedures are feasible in neck surgery. All methods depending on the surgeons' experience describe no significantly extended operation times, a better and faster wound-healing and an optimized cosmetic outcome, compared to open approaches. Surgeons should always be aware of the limitations of the minimal invasive techniques regarding the complications or modifications during neck dissection/thyroidectomy.

Distribution of mucins and antimicrobial substances lysozyme and lactoferrin in the laryngeal subglottic region.

The subglottic region of the larynx is of high clinical relevance with regard to infections and malignancies. Little is known about the distribution of mucins and antimicrobial substances in this area. In this study, we have investigated the mucin distribution in the normal subglottis of the larynx. Moreover, we analysed the expression of lysozyme and lactoferrin in this area. Therefore, the subglottic region of 34 larynges was investigated immunohistochemically with different antibodies to mucins and antimicrobial substances. The epithelium reacted positive with antibodies to mucins MUC1 (34/34), 5AC (26/34), 5B (10/34), 7 (8/34), 8 (10/34) and 16 (19/34); submucosal glands were positive to mucins MUC1 (34/34), 5B (10/34), 7 (8/34), and 16 (19/34); high columnar epithelial cells and serous parts of subepithelial seromucous glands were also positive for lysozyme (34/34) and lactoferrin (34/34). The results show that human subglottic epithelium and subepithelial submucosal glands produce a broad spectrum of mucins that is almost comparable with that in other areas of the respiratory tract. We hypothesize that the mucin diversity of the subglottis has an impact on positive functional consequences during vocal production and antimicrobial defence. This antimicrobial defence is supported by synthesis and secretion of antimicrobial substances such as lysozyme and lactoferrin. Moreover, knowledge of the observed distribution pattern of mucins in the subglottis can be a useful tool for a classification of subglottic laryngeal carcinomas.

Anatomical definition of the subglottic region.

BACKGROUND: Due to laryngeal neoplasia, as well as infectious and autoimmune diseases, the subglottic region is of great clinical relevance. However, descriptions of the subglottic structures are inconsistent. The aim of our study was to present a precise analysis of the subglottic region and derive functional and clinical conclusions. METHODS: Histological, histochemical and immunohistochemical investigations as well as scanning electron microscopy were performed and combined with injection techniques applied to the subglottic region of the larynges of 33 body donors. RESULTS: The three-dimensional extensions of the subglottic region were newly defined: the inferior arcuate line of the vocal cord was defined as the cranial border. The lower margin of the cricoid is the caudal border. Craniolaterally, the elastic cone and, further caudally, the cricoid form the border. Therefore, the definition presented comprises heretofore unnamed ventral and dorsal parts of the lower larynx. The subglottic region can be described as cylindrical, becoming smaller in the cranial direction, following the elastic cone. The ventral boundary is formed by the median part of the cricothyroid ligament (ligamentum conicum), the dorsal part by the cricoid cartilage. The walls of the subglottis are divided into three or four layers composed of collagenous and elastic fibres in which seromucous glands are embedded. Subglottic blood vessels including a tight subepithelial capillary plexus were delineated. CONCLUSION: The new definition of the subglottic extensions presented is helpful and essential for precise laryngeal tumour classification. The results indicate that the boundaries are unlikely to counteract tumour progression in the subglottis. Furthermore, the findings suggest that these structures contribute to temperature regulation of breath, protection against inflammation as well as breath frequency and depth-dependent mucus secretion.

TFF peptides in the human false vocal folds of the larynx.

TFF peptides (formerly P domain peptides, trefoil factors) are typical secretory products of mucin-producing cells and are thought to influence the rheological properties of mucous gels. We investigated the localization of these peptides in the human false vocal folds of the larynx, also known as the ventricular folds or vestibular folds. An analysis of TFF peptide mRNA by RT-PCR and TFF protein by Western blot detected TFF1 and TFF3, but not TFF2. Immunohistochemistry revealed TFF1 to be associated with the secretory product of goblet cells and mucous parts of subepithelial seromucous glands. TFF3 occurred in columnar epithelial cells of the mucosa and in serous cells and excretory duct cells of seromucous glands. These peptides may play a role in the rheological function of mucus secreted onto the true vocal folds and are thus important constituents of vocal production.

The human false vocal folds -- an analysis of antimicrobial defense mechanisms.

Inflammatory processes often lead to pathologic changes in the area of the larynx. A moistening function of the false vocal folds has been described frequently. Up to now we have little knowledge of the role of the false vocal folds in protection against pathogenic agents. The present study analyzes the structures of the false vocal folds in their relations to antimicrobial defense mechanisms. Investigations were performed on false vocal folds of larynges from 34 cadavers using histologic, histochemical and immunohistochemical methods. Seromucous glands, together with epithelial and goblet cells of the folds, synthesize a complex mucus layer. In all of the investigated samples this layer contains carbohydrates including N-acetyl-glucosamine, N-acetyl-galactosamine, galactose, mannose, fucose, and sialic acids. Furthermore, antimicrobial peptides like lactoferrin, lysozyme, alpha and beta defensins are also found in these structures. IgA, produced by plasma cells in the false vocal folds, is frequently integrated in the secretory product. Synthesized mucins, antimicrobial peptides and immunoglobulins form a specialized protective substance that is secreted mainly at the true vocal folds. Here the layer functions to lubricate the true vocal folds, resulting in positive functional consequences during vocal production. Moreover, together with immunocompetent cells, the protective layer seems to play a major role in antigen defense and prevents invasion of pathogenic agents.

Bevacizumab induces regression of vestibular schwannomas in patients with neurofibromatosis type 2.

Bilateral vestibular schwannomas are the hallmark of neurofibromatosis type 2 (NF2), and these tumors impair hearing and frequently lead to deafness. Neurosurgical intervention, the only established treatment, often damages the vestibular nerve. We report 2 cases in which treatment with bevacizumab (for 3 months in one case and 6 months in the other) induced regression of progressive vestibular schwannomas by more than 40% and substantially improved hearing in the patient treated for 6 months. Bevacizumab therapy may thus provide an effective treatment for progressive vestibular schwannomas in patients with NF2.

Amifostine is a potent radioprotector of salivary glands in radioiodine therapy. Structural and ultrastructural findings.

BACKGROUND AND PURPOSE: Salivary gland impairment following high-dose radioiodine treatment is well recognized. Since differentiated thyroid cancer has a good prognosis, reduction of long-term side effects is important. This study investigates the radioprotective effects of amifostine in salivary glands of rabbits receiving high-dose radioiodine therapy so as to obtain deeper insight in changes on the cellular and ultrastructural level. MATERIAL AND METHODS: A total of 20 rabbits were investigated. High-dose radioiodine therapy applying 1 GBq (131)I was performed in 16 animals. Eight of these 16 animals received 200 mg/m(2) body surface amifostine prior to high-dose radioiodine therapy. Four additional rabbits served as controls, two receiving amifostine, the other two no treatment at all. Subsequently, salivary glands (submandibular and parotid glands, respectively) of all animals were examined by light and transmission electron microscopy. RESULTS: Parenchymal damage of both parotid and submandibular glands, specially acinar structures comprising cell organelles and nuclei, of animals pretreated with amifostine was much less pronounced than in animals without amifostine pretreatment. CONCLUSION: The results indicate that parenchymal damage in salivary glands induced by high-dose radioiodine therapy can significantly be reduced by amifostine. Therefore, amifostine therapy may increase quality of life in patients with differentiated thyroid cancer after radioiodine treatment.

Region-specific immunological response of the different laryngeal compartments: significance of larynx-associated lymphoid tissue.

The occurrence of primary extranodal marginal-zone B-cell lymphoma [of the mucosa-associated lymphoid tissue (MALT) type] has only been described in the supraglottic region, implying that preexistent organized lymphoid tissue is present at that site only. To date, studies have not established clearly whether organized MALT shows a site-related distribution in the larynx. The supraglottic region of the false vocal folds and the subglottis from 87 unselected cadavers with no known history of nasal, oral, pharyngeal, laryngeal, tracheal, or esophageal disease were examined for the presence of organized MALT. Organized lymphoid tissue was found with the cytomorphological and immunophenotypic features of MALT in 100% of false vocal folds of children and in more than 90% of adolescents, decreasing to 7.1% in persons in their sixth decade, whereas MALT was completely absent in the subglottis in all age groups. The results explain why primary extranodal marginal-zone B-cell lymphoma has only been described in the supraglottic region but is absent in the subglottis. Moreover, the results suggest a region-specific immunological response of the different laryngeal areas as reflected in clinical observations and animal studies. However, the impact on presence or absence of laryngeal MALT awaits clarification.