Retrospective Cohort Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Feb 28, 2016; 8(2): 192-199
Published online Feb 28, 2016. doi: 10.4329/wjr.v8.i2.192
Impaired swallowing mechanics of post radiation therapy head and neck cancer patients: A retrospective videofluoroscopic study
William G Pearson Jr, Alisa A Davidoff, Zachary M Smith, Dorothy E Adams, Susan E Langmore
William G Pearson Jr, Department of Cellular Biology and Anatomy, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, United States
William G Pearson Jr, Department of Otolaryngology, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, United States
Alisa A Davidoff, Zachary M Smith, Dorothy E Adams, Sargent College, Boston University, Boston, MA 02118, United States
Susan E Langmore, Department of Otolaryngology Head and Neck Surgery, Boston University School of Medicine, Boston, MA 02118, United States
Author contributions: All authors contributed to this study in accordance with the standard proposed by International Committee of Medical Journal Editors; Pearson WG Jr and Langmore SE designed the research study; Pearson WG Jr, Davidoff AA, Smith ZM and Adams DE performed the research; Pearson WG Jr analyzed the data and wrote the paper with input from all other authors.
Institutional review board statement: The study was reviewed and approved by the Boston University School of Medicine Institutional Review Board.
Informed consent statement: The Boston University School of Medicine Institutional Review Board approved a waiver of informed consent due to the use of existing clinical data collected in a manner that subjects cannot be identified, and the added risk of the invasion of privacy and possible compromise of confidentiality introduced by obtaining consent.
Conflict-of-interest statement: All the authors have no conflict of interest related to the manuscript.
Data sharing statement: Data were collected and analyzed under a research protocol approved by the Boston University School of Medicine Institutional Review Board that waived consent due to the added risk of the invasion of privacy and possible compromise of confidentiality introduced by obtaining consent. These data were first reported in the doctoral dissertation of William G Pearson, Jr., with the copyright belonging to the author.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: William G Pearson Jr, PhD, Assistant Professor of Cellular Biology and Anatomy, Medical College of Georgia at Georgia Regents University, 1120 15th Street, CB-1101, Augusta, GA 30912, United States. wpearson@gru.edu
Telephone: +1-706-7213811 Fax: +1-706-7216120
Received: July 31, 2015
Peer-review started: August 1, 2015
First decision: September 28, 2015
Revised: October 24, 2015
Accepted: December 18, 2015
Article in press: December 18, 2015
Published online: February 28, 2016
Abstract

AIM: To determine swallowing outcomes and hyolaryngeal mechanics associated with post radiation therapy head and neck cancer (rtHNC) patients using videofluoroscopic swallow studies.

METHODS: In this retrospective cohort study, videofluoroscopic images of rtHNC patients (n = 21) were compared with age and gender matched controls (n = 21). Penetration-aspiration of the bolus and bolus residue were measured as swallowing outcome variables. Timing and displacement measurements of the anterior and posterior muscular slings elevating the hyolaryngeal complex were acquired. Coordinate data of anatomical landmarks mapping the action of the anterior muscles (suprahyoid muscles) and posterior muscles (long pharyngeal muscles) were used to calculate the distance measurements, and slice numbers were used to calculate time intervals. Canonical variate analysis with post-hoc discriminant function analysis was performed on coordinate data to determine multivariate mechanics of swallowing associated with treatment. Pharyngeal constriction ratio (PCR) was also measured to determine if weak pharyngeal constriction is associated with post radiation therapy.

RESULTS: The rtHNC group was characterized by poor swallowing outcomes compared to the control group in regards to: Penetration-aspiration scale (P < 0.0001), normalized residue ratio scale (NRRS) for the valleculae (P = 0.002) and NRRS for the piriform sinuses (P = 0.003). Timing and distance measurements of the anterior muscular sling were not significantly different in the two groups, whereas for the PMS time of displacement was abbreviated (P = 0.002) and distance of excursion was reduced (P = 0.02) in the rtHNC group. A canonical variate analysis shows a significant reduction in pharyngeal mechanics in the rtHNC group (P < 0.0001). The PCR was significantly higher in the test group than the control group (P = 0.0001) indicating reduced efficiency in pharyngeal clearance.

CONCLUSION: Using videofluoroscopy, this study shows rtHNC patients have worse swallowing outcomes associated with reduced hyolaryngeal mechanics and pharyngeal constriction compared with controls.

Keywords: Swallow mechanics, Post radiation, Head and neck cancer, Fluoroscopy, Anatomy

Core tip: Quality videofluoroscopic imaging of barium swallows is useful to determine swallowing outcomes for safe and efficient swallowing, conventional kinematics, and underlying functional anatomy associated with outcomes. This retrospective study of radiation therapy head and neck cancer (rtHNC) patients compared with age and gender matched controls and found that swallowing outcomes were significantly worse in rtHNC patients. Conventional kinematics indicated a reduction in laryngeal elevation. Computational analysis of swallowing mechanics using coordinate data of anatomical landmarks is here used to visualize impaired functional anatomy associated with poor outcomes in order to suggest particular targets for rehabilitation.