Functional Swallowing Units (FSUs) as organs-at-risk for radiotherapy. PART 1: Physiology and anatomy. (January 2019)

• Record Type: Journal Article
• Authors: Gawryszuk, Agata; Bijl, Hendrik P.; Holwerda, Monique; Halmos, Gyorgy B.; Wedman, Jan; Witjes, Max J.H.; van der Vliet, Anton M.; Dorgelo, Bart; Langendijk, Johannes A.
• Is Part Of: Radiotherapy and oncology. Volume 130(2019)
• Page Start: 62
• Page End: 67
• Publication Date: 2019-01
• Subjects: SWOARs Swallowing Organs At Risk -- HLE Hyolaryngeal Elevation -- TBR Tongue Base Retraction -- FSUs Functional Swallowing Units -- FOM Floor of Mouth -- THM Thyrohyoid Muscles -- PDS Posterior Digastric/Stylohyoid Muscles Complex -- LPM Longitudinal Pharyngeal Muscles -- HSG Hyoglossus/Styloglossus Muscles Complex -- GGS Genioglossus Muscles Complex -- ITM Intrinsic Tongue Muscles -- NTCP Normal Tissue Complication Probability; Head and neck cancer -- Swallowing organs at risk -- (Chemo)radiation -- Hyolaryngeal elevation -- Tongue base retraction; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2018.10.028
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: Hyolaryngeal Elevation and Tongue Base Retraction are crucial swallowing components. Additional swallowing structures are defined based on swallowing physiology. Swallowing sparing strategies should probably reach beyond pharyngeal constrictors. Abstract: Background and purpose: When optimising radiotherapy treatments today, the pharyngeal constrictor muscles and the larynx are usually regarded as the swallowing organs at risk (SWOARs). The purpose of this study was to identify and describe additional, previously undefined groups of muscles (functional units) involved in crucial components of swallowing (hyolaryngeal elevation (HLE), tongue base retraction (TBR) and tongue motion), and to emphasise their relevance in radiation-induced dysphagia. Material and methods: Based on available literature on human anatomy and swallowing physiology, the functional units of muscles involved in HLE, TBR and tongue motion have been identified and described. Results and conclusion: Functional swallowing units (FSUs) were defined as groups of swallowing muscles sharing their function, that are in close proximity to each other. Seven FSUs involved in HLE, TBR and tongue motion were identified: floor of mouth, thyrohyoid muscles, posterior digastric/stylohyoid muscles complex, longitudinal pharyngeal muscles, hyoglossus/styloglossus muscles complex, genioglossus muscles, intrinsic tongue muscles. The swallowing physiology and anatomy of the FSUs described in this paper will lead to a greater understanding of radiation-induced dysphagia mechanisms and, consequently, to an improvement in the development of swallowing sparing strategies. This article (PART 1) serves as the theoretical foundation for a subsequent article (PART 2), which provides detailed delineation guidelines for FSUs.