Pathological changes in the subsynovial connective tissue increase with self-reported carpal tunnel syndrome symptoms

Blood Flow Changes in Subsynovial Connective Tissue on Contrast‐Enhanced Ultrasonography in Patients With Carpal Tunnel Syndrome Before and After Surgical Decompression

“…Ultrasonography has been commonly used for examining CTS, 16,17 and analyses of the morphologic and functional changes in the subsynovial connective tissue in patients with CTS using high-resolution US has been reported. 7,18 However, to our knowledge, there has been no report concerning blood flow in the subsynovial connective tissue. It is important to evaluate the microcirculation around the carpal tunnel when studying the pathophysiologic mechanisms of CTS because transient ischemia is thought to affect the occurrence of CTS.…”

“…Ultrasonography has been commonly used for examining CTS, and analyses of the morphologic and functional changes in the subsynovial connective tissue in patients with CTS using high‐resolution US has been reported . However, to our knowledge, there has been no report concerning blood flow in the subsynovial connective tissue.…”

“…Although various factors are considered to cause CTS, recent studies have reported that one of the most important factors is a qualitative alteration of subsynovial connective tissue in the carpal tunnel, which leads to an increase in pressure on the carpal tunnel or a microcirculatory disturbance in the median nerve . Some studies have reported that the histopathologic changes in the subsynovial connective tissue in patients with CTS included noninflammatory fibrosis and thickening, whereas others showed thickening of the subsynovial connective tissue in patients with CTS using magnetic resonance imaging and ultrasonography (US) . Although alteration of the microcirculation in the subsynovial connective tissue is considered to be very important in the pathophysiologic mechanisms of CTS, it has been difficult to obtain detailed information about the blood flow in the subsynovial connective tissue in patients with CTS because of the lack of an evaluation method.…”

Ultrasound‐guided hydrodissection decreases gliding resistance of the median nerve within the carpal tunnel

“…The most common histological finding in CTS is noninflammatory fibrosis of SSCT surrounding the tendons in the carpal tunnel. 9,12,33 Several studies suggest that fibrosis leads to decreased motion of the MN within the carpal tunnel. [13][14][15] Freeing the MN from the TCL and surrounding tendons by dissecting the SSCT might result in restoration of the normal kinematics within the carpal tunnel, thereby reducing symptoms.…”

“…5,6 Corticosteroid injections often provide temporary relief, but approximately half of injected patients require further treatment within 1 year. 5,7,8 Previous research has shown that the subsynovial connective tissue (SSCT) surrounding the tendons in the carpal tunnel is thickened and fibrotic in CTS patients compared with normal individuals, [9][10][11][12] and this thickening appears to result in reduced motion of the MN within the carpal tunnel. [13][14][15][16] While the relationship between fibrosis and neuropathy is still unknown, this reduction of mobility can prevent the nerve from moving aside as the tendons move anteriorly during strong grip or pinch.…”