## 4 Discussion  
In this study, a significant reduction in the radial-ulnar translation distance of the MN during finger movement was observed in patients diagnosed with CTS. This observation is further supported by the notable findings that both radial-ulnar velocity and magnitude velocity were significantly reduced in the CTS group. These findings provide robust support for the hypothesis that fibrosis and adhesions within the SST significantly limit the mobility of the MN within the confines of the carpal tunnel, thereby impeding the smooth motion of this important neural structure [3; 18]. In particular, this study represents a pioneering effort as it marks the first attempt to meticulously measure both the transverse displacement and velocity of the MN through the use of a state-of-the-art DL model, specifically the CTS detection model. This approach introduces a new dimension to the study of CTS and its impact on MN dynamics. Typically, the diagnosis of obstructive neuropathies such as CTS has relied primarily on dynamic US imaging, a technique in which the entrapped nerve exhibits atypical spatiotemporal changes due to the motion of adjacent tissues. A meta-analysis dedicated to the evaluation of MN mobility in CTS patients using US imaging revealed interesting findings. In particular, it was shown that CTS patients had consistently reduced MN displacement compared to the healthy controls. The aggregate results of this analysis showed that the standardized mean difference (SMD) was \(-\)1.612 (95% confidence interval [CI]; \(-\)3.173 to \(-\)0.051) during finger flexion or hand grip [31]. Although the reductions in MN displacement in the dorsopalmar and radioulnar axes did not reach statistical significance within the CTS group, the SMD values were \(-\)0.795 (95% CI: \(-\)1.886 to 0.295) and \(-\)0.855 (95% CI: \(-\)2.068 to 0.358), respectively [31]. There are 12 previous studies that investigated transverse MN displacement using US imaging, and they showed heterogeneous methodologies. Eight of them compared static images during finger extension and flexion [14; 20; 21; 22; 23; 25; 38; 39], two used particle tracking via the speckle tracking method [17; 40], and one of them introduced a novel algorithm to measure the MN motion area [41]. However, these methods often require the labor-intensive manual tracing of the trapped nerves, and most studies evaluate MN motion only at the initial and final frames, which might not have adequately captured the real-time displacement and dynamics of the MN during finger motion. Only one study used a DL model to quantify the centroid offset of the  
Figure 5: The X velocity and the magnitude velocity were significantly lower in the CTS group than in the control group. The Y velocity showed no significant difference between the two groups. MN during finger movement [27]. Various previous studies have reported the transverse MN displacement at the radioulnar axis and the dorsopalmar axis (Tables 2 and 3). In the present study, as in many other studies, MN displacement in the radioulnar axis was significantly lower in the CTS group than in the control group. On the other hand, in the present study, the displacement in the dorsopalmar axis showed no significant difference between the groups in the present study. As described by [PERSON] et al., the MN is pulled to the radial side by the flexor tendons during finger flexion [22], so the movement on the radioulnar axis might be more susceptible to adhesions with the SSCT and the flexor tendons. In the present study, we successfully assessed not only MN displacement but also MN velocity and demonstrated its reduction in the CTS group, especially in the radioulnar axis. This analysis serves to provide a more nuanced understanding of MN dynamics in the context of CTS and offers the tantalizing prospects of real-time US assessments. Importantly, the results of this study fit seamlessly with previous studies of MN mobility, further validating the robustness of these findings.