![]() Immobilization of each patient for simulation and during treatment was achieved with a thermoplastic head and shoulder mask (Civco, Orange City, IA). For this purpose, Christianen et al 22 recently defined guidelines for SWOARs contouring.īased on these findings, the aim of this retrospective analysis is to evaluate potential relationships between planned dose–volume parameters and observed incidence of acute and late dysphagia in patients with HNC treated with IMRT or VMAT, after a recontouring of the PCs according to these recently published guidelines. 19– 21 These studies obtained different results, maybe, owing to a number of methodological issues and to the ambiguous contouring of the PCs. 14– 18 More authors hypothesized that sparing a portion of the constrictor muscles (PCs), not involved by tumour and not at risk of subclinical disease, might reduce dysphagia. Open questions remain for SWOARs, especially with reference to the delineation modalities of the involved structures to the volumes or the dose constraints to be applied. ![]() Regarding tolerance of the parotid glands, several studies have suggested significant recovery when the mean dose is inferior to 26 Gy. 4– 8 In comparison with three-dimensional-conformal radiation therapy, several studies have shown that IMRT in HNC treatment reduces overall adverse effects such as xerostomia and dysphagia and thus improves QoL, even when chemotherapy is added. Intensity-modulated radiation therapy (IMRT) and rotational intensity-modulated techniques, including volumetric-modulated arc therapy (VMAT), allow for a better dose conformation to target structures while reducing the dose. However, xerostomia and dysphagia often remain relevant side effects for patients with HNC, compromising their quality of life (QoL), as a consequence of radiation damage to the parotid glands and to the organ at risk (OAR) involved in the swallowing process (SWOARs). Several reports show that radiotherapy (RT) with concomitant chemotherapy or altered fractionation schedules improve tumour control and survival rate. Hyoglossus lingual artery middle constrictor stylohyoid triticeal cartilage.In the past decade, substantial progress has been made in the treatment of head and neck cancer (HNC). The fiber arrangement suggested that, besides constriction of the pharynx, the ascending and descending fibers of the middle constrictor can act as an elevator muscle, and the irregular attachments could affect the functions of the muscles and vessels. The ascending and descending fibers rarely reached the top of the pharynx and the thyroid cartilage, respectively. The three groups were inserted into the pharyngeal raphe, and the descending fibers joined the longitudinal pharyngeal muscles. Some fibers attached to the hyoglossus, occasionally to the stylohyoid and the posterior belly of the digastric, but seldom to the lingual artery and the triticeal cartilage in the thyrohyoid ligament. The posteroinferior group fanned out from the posterior part of the greater horn, while the middle constrictor arose internally to the hyoglossus some fibers often passed externally, and their fibers sometimes intersected around the lingual artery, which ran between them. The middle group ascended posterosuperiorly from the greater horn and fanned out. The anterosuperior group ascended posterosuperiorly from the ligament and the lesser horn and fanned out. The middle constrictor arose from the stylohyoid ligament and the hyoid bone, and its fibers were divided into three overlapping groups. The gross anatomies of the pharyngeal and neighboring muscles were examined in 41 cadavers. This study investigated the attachments of the middle constrictor to clarify its configuration and re-examine its functions. Such arrangements make the interrelationships among pharyngeal muscles complicated. The pharyngeal muscles overlap each other and some of their parts have different areas of origin.
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