Yang Yang, Xu Xinlin, Zhuang Peiyun
Department of Voice, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China.
Department of Voice, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China.
J Voice. 2024 Jul 24. doi: 10.1016/j.jvoice.2024.07.003.
This research aims to discern the evolving nature of the biomechanical properties of vocal fold scarring by calculating Young's modulus for the vocal fold cover layer, the body layer, and the structure as a whole. The study also investigates the potential of diffusion tensor imaging (DTI) for determining these biomechanical characteristics quantitatively.
A total of six adult female Beagles were divided into two groups (A and B groups) for the creation of unilateral vocal fold scar models, each group containing three subjects. Five months postmodel creation, larynxes were excised and placed within a 9.4T BioSpec MRI system (Bruker, Germany) for scanning. Subsequently, the vocal folds were segregated from the larynx. In A group of Beagles, the vocal fold cover layer and body layers were separated, whereas in B group they remained intact. All samples were then subjected to cyclic tensile testing using an Instron MicroTester 5948, with Young's modulus computed for the vocal fold cover layer and body layers in the A group and for the intact vocal fold in the B group. Differences in the overall Young's modulus between the vocal fold scarred side and the healthy side were analyzed, and a Pearson correlation analysis was performed between DTI parameters and the outcomes of the stress-strain experiments.
A statistically significant discrepancy in the overall Young's modulus was identified between the scar and healthy sides of the vocal fold (P = 0.0401). The Young's modulus also displayed a significant difference between the scar and healthy sides of the vocal fold cover layer (P = 0.0241). No meaningful divergence was observed in the elastic modulus between the scar and healthy sides of the vocal fold body layer (P > 0.05). Postseparation, Young's modulus for both the cover and body layers of the scarred vocal fold were less than that of the same layers on the healthy side. However, Young's modulus of the entirety of the vocal fold on the scar side was greater than that of the whole vocal fold on the healthy side. The fractional anisotropy (FA) of the vocal fold cover layer had a significant correlation with the elastic modulus (r = 0.812, P = 0.050), as did the Tensor trace (r = -0.821, P = 0.045). The FA of the vocal fold body layer showed no significant correlation with the elastic modulus (r = -0.725, P = 0.103), while the Tensor trace demonstrated a significant correlation (r = 0.911, P = 0.012).
Biomechanical alterations in vocal fold scars demonstrate a closer association with adhesion bands, thus emphasizing the importance of adhesion band loosening for the restoration of vibratory function within vocal fold scarring. DTI emerges as a potent noninvasive quantitative instrument for assessing these biomechanical changes, as well as for quantitatively gauging the severity of vocal fold scarring.
本研究旨在通过计算声带覆盖层、体层以及整个结构的杨氏模量，来识别声带瘢痕生物力学特性的演变性质。该研究还调查了扩散张量成像（DTI）在定量确定这些生物力学特征方面的潜力。
总共6只成年雌性比格犬被分为两组（A组和B组）以创建单侧声带瘢痕模型，每组包含3只实验对象。造模后5个月，切除喉部并置于9.4T BioSpec MRI系统（德国布鲁克公司）中进行扫描。随后，从喉部分离出声带。在A组比格犬中，将声带覆盖层和体层分离，而在B组中它们保持完整。然后使用Instron MicroTester 5948对所有样本进行循环拉伸测试，计算A组声带覆盖层和体层以及B组完整声带的杨氏模量。分析声带瘢痕侧与健康侧之间整体杨氏模量的差异，并对DTI参数与应力 - 应变实验结果进行Pearson相关分析。
声带瘢痕侧与健康侧之间在整体杨氏模量上存在统计学显著差异（P = 0.0401）。声带覆盖层瘢痕侧与健康侧之间的杨氏模量也显示出显著差异（P = 0.0241）。声带体层瘢痕侧与健康侧之间在弹性模量上未观察到有意义的差异（P > 0.05）。分离后，瘢痕化声带的覆盖层和体层的杨氏模量均小于健康侧相同层的杨氏模量。然而，瘢痕侧整个声带的杨氏模量大于健康侧整个声带的杨氏模量。声带覆盖层的分数各向异性（FA）与弹性模量具有显著相关性（r = 0.812，P = 0.050），张量迹（Tensor trace）也是如此（r = -0.821, P = 0.045）。声带体层的FA与弹性模量无显著相关性（r = -0.725, P = 0.103），而张量迹显示出显著相关性（r = 0.911, P = 0.012）。
声带瘢痕中的生物力学改变与粘连带显示出更紧密的关联，从而强调了粘连带松解对恢复声带瘢痕内振动功能的重要性。DTI成为一种强大的非侵入性定量工具，可用于评估这些生物力学变化，以及定量测量声带瘢痕的严重程度。
