Department of Rehabilitation Medicine, Daegu Fatima Hospital, Daegu, Republic of Korea.
Department of Physical Medicine and Rehabilitation, Ulsan University Hospital, University of Ulsan College of Medicine, 877, Bangeojinsunghwndo-ro, Dong-gu, Ulsan, 44033, Republic of Korea.
Sci Rep. 2020 Sep 24;10(1):15607. doi: 10.1038/s41598-020-72757-2.
There are conflicting hypotheses regarding the initial pathogenesis of carpal tunnel syndrome (CTS). One hypothesis characterizes it as inflammation of the median nerve caused by compression, while another hypothesis characterizes CTS as non-inflammatory fibrosis of the subsynovial connective tissue (SSCT). This study aimed to investigate the differences in the ultrasonography parameters before and after a steroid injection, which is effective for CTS, to elucidate the initial pathogenesis of CTS and the mechanisms of action of the injected steroid. Fourteen hands from 14 healthy participants and 24 hands from 24 participants with mild CTS were examined. Dynamic movement and morphology of the median nerve before and after steroid injection were measured. There was no significant difference in the normalized maximal distance of the median nerve, which reflects the degree of fibrosis in the SSCT indirectly, during finger and wrist movements before and after the injection among patients with CTS (p > 0.05). Among the parameters that indirectly reflects the degree of median nerve compression, such as normalized maximal change in the aspect ratio of the minimum-enclosing rectangle (MER), maximal change in the median nerve perimeter, and maximal value of the median nerve cross-sectional area (CSA), statistically significant differences were not observed between values of the normalized maximal change in the aspect ratio of the MER and maximal change in the median nerve perimeter, during finger and wrist movements recorded before and after the injection in patients with CTS (p > 0.05). However, multivariate logistic regression analysis revealed that the change in the normalized maximal value of the median nerve CSA, according to finger and wrist movement was correlated with the administration of the steroid injection (p < 0.05). In conclusion, compared to that noted before steroid injection, the median nerve CSA noted during finger and wrist movements changed significantly after injection in patients with mild CTS. Given the improvement in median nerve swelling after steroid injection, but no improvement in the movement of the median nerve during finger and wrist movements, median nerve swelling due to compression (rather than fibrosis of the SSCT may be the initial pathogenesis of early-stage (mild) CTS, and the fibrous changes around the median nerves (SSCT) may be indicative of secondary pathology after median nerve compression. Further studies are required to validate the findings of our study and confirm the pathogenesis of CTS.
对于腕管综合征（CTS）的初始发病机制存在相互矛盾的假说。一种假说将其特征描述为正中神经受压引起的炎症，而另一种假说将 CTS 特征描述为滑膜下结缔组织（SSCT）的非炎症性纤维化。本研究旨在探讨类固醇注射后对 CTS 有效的超声参数的变化，以阐明 CTS 的初始发病机制和注射类固醇的作用机制。检查了 14 名健康参与者的 14 只手和 24 名轻度 CTS 参与者的 24 只手。测量类固醇注射前后正中神经的动态运动和形态。在接受 CTS 治疗的患者中，注射前后手指和手腕运动期间，间接反映 SSCT 纤维化程度的正中神经最大距离的归一化最大值（NRMD）没有显著差异（p>0.05）。在间接反映正中神经压迫程度的参数中，如最小包络矩形（MER）的归一化最大纵横比的最大变化、正中神经周长的最大变化和正中神经截面积（CSA）的最大值，在接受 CTS 治疗的患者中，注射前后手指和手腕运动记录的 MER 最大纵横比的归一化最大变化和正中神经周长的最大变化值之间没有观察到统计学上的显著差异（p>0.05）。然而，多元逻辑回归分析显示，根据手指和手腕运动，NRMD 的最大变化与类固醇注射的给药相关（p<0.05）。总之，与注射前相比，轻度 CTS 患者注射后手指和手腕运动期间的正中神经 CSA 明显变化。鉴于类固醇注射后正中神经肿胀的改善，但手指和手腕运动期间正中神经运动没有改善，由于压迫导致的正中神经肿胀（而不是 SSCT 的纤维化）可能是早期（轻度）CTS 的初始发病机制，而正中神经周围的纤维性变化（SSCT）可能是正中神经受压后的继发病理。需要进一步的研究来验证我们的研究结果并确认 CTS 的发病机制。
