Morphological and functional changes of the geniohyoid muscle in elderly patients after hip fracture surgery: comparison of ultrasound images with a focus on swallowing function

Abstract

Abstract Background: The geniohyoid muscle (GH) plays an important role for the hyo-laryngeal movements during swallowing. The purpose of this study was to clarify whether the muscle mass and contraction (shortening) of the GH change in elderly patients after hip fracture surgery using ultrasound imaging. Methods: The participants were 25 women over 65 years of age who underwent hip fracture surgery. The participants were divided into two groups based on the results of swallowing assessment by water drinking: one with normal swallowing function (NSF) and the other with suspected decline in swallowing function (DSF). The sagittal cross-sectional area (SA) of the GH and the shortening rate (SR) were compared at two time points: immediately and two weeks after surgery. Wilcoxon's signed rank test was performed for the comparison of the SA and SR between two time periods in all patients. Wilcoxon's signed rank test was also used for the intra-group comparison between the NSF and the DSF immediately and two weeks after surgery. The Mann-Whitney U test was used for the comparison between the NSF and the DSF, with respect to changes in the SA and SR at two time points. Results: The SA of the GH decreased significantly at two weeks after surgery in both groups, regardless of swallowing function, and tended to decrease more in the NSF group. The rate of shortening did not change significantly at two weeks after surgery. However, the DSF group showed a significant decrease in intra-group comparison between two time points, and showed a significantly lower values than the NSF group in the inter-county comparison. The participants in the NSF group showed two types of changes: worsening and improvement in the shortening rate of the GH during the two-week postoperative period. Conclusions: Atrophy of the GH were observed in both NSF and DSF groups, suggesting the importance of continuous swallowing assessment in the elderly individuals during their perioperative period, even for those whose swallowing function are within normal limits.