Study of pathophysiology for dysphagia by means of quantitative analysis with videofluorogram of swallowing

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 12671672
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Otorhinolaryngology
• Research Institution: KYUSHU UNIVERSITY
• Principal Investigator: UMEZAKI Toshiro KYUSHU UNIVERSITY, Kyushu University, Faculty of Medicine, Associate Professor (80223600)
• Co-Investigator(Kenkyū-buntansha): ADACHI Kazuo Kyushu University, Faculty of Medicine, Assistant Professor (90380386) ; THO Satoshi Kyushu University, Faculty of Medicine, Assistant Professor (20380397)
• Project Period (FY): 2000 – 2002
• Keywords: videofluorogram for swallowing / dysphagia / quantitative analysis / LEDT (delay time of laryngeal elevation) / pharyngeal clearance / ageing / neck dissection / irradiation therapy

Research Abstract

This research has elucidated that the swallowing function is maintained comparatively well even in the aged, judged from the measurement of pharyngeal clearance, and the mean value of the pharyngeal clearance during swallowing in the healthy subjects is 90% or more, which is observed without sexual differences. In the aged over 65 years old, however, the negative correlation was observed between the age and pharyngeal clearance. Also, it became clear that while the vertical position of the larynx at rest descends in proportion to age, delay time of the laryngeal elevation (LEDT) is almost constant up to the 70's ; thus the laryngeal elevation is not delayed because of the compensatory increase of the laryngeal excursion from the bottom at rest to the uppermost position during pharyngeal swallowing in accordance with ageing.
Based on the above-mentioned results, we analyzed the influences of the irradiation to the head and neck cancers and the surgical operation of the head and neck on t he LEDT (excitability of eliciting pharyngeal swallowing) and the pharyngeal clearance during swallowing. Many cases of those showed decrease of the pharyngeal clearance ; especially in the case with radical neck dissection impaired pharynx contraction on the side of neck dissection was observed. The LEDT was prolonged especially in the majority of the irradiation cases. It was confirmed that there were many cases of which swallowing function was deteriorated even without aspiration in those cases. It was suggested from these studies that the decline of propelling force during swallowing was induced by dysfunction of the pharyngeal constrictors caused by the damage of the pharyngeal branch of the vagus nerve in case of the neck operation. It was conceivable that the laryngeal elevation is delayed because of the pharyngeal sensory disturbance by irradiation. We should avoid the expansion of unnecessary dissect of the neck tissue, which become the cause of scar formation and also a damage of the pharyngeal branch of the vagus, and confirm that it is possible to avoid deterioration of the swallowing function by preserving the nerve. It is emphasized that we should pay attention to operation of the head and neck malignant tumor not only to improve the treatment outcomes but to preserve such function proper to head and neck organ as swallowing.