Palmar bowing of the flexor retinaculum on wrist MRI correlates with subjective reports of pain in carpal tunnel syndrome

Abstract

Purpose:To investigate the utility of palmar bowing of the flexor retinaculum (PBFR) on magnetic resonance imaging (MRI) as an adjunct to presurgical evaluation of carpal tunnel syndrome (CTS). Materials and Methods:The CTS group comprised 48 women with CTS diagnosed from clinical history, physical examination, and electrophysiological findings. Another 21 healthy women with no symptoms of CTS served as controls. The CTS group was divided into four subgroups based on symptom duration. CTS patients were preoperatively assessed for symptom severity using a Likert scale. In both groups, palmar bowing of the flexor retinaculum (PBFR) was measured on MRI. Furthermore, relationships with disease duration, subjective symptom severity, and electrophysiological findings were assessed in the CTS group.Results: Although PBFR increased significantly in all CTS groups when compared to the control group, PBFR in patients who complained of severe pain tended to exceed that in patients with mild to moderate pain. Statistical analysis showed a positive correlation between PBFR and pain severity. In contrast, PBFR did not reflect median nerve function.Conclusion: PBFR as seen on MRI seems to correlate significantly with patients' subjective reports of pain severity.Key Words: carpal tunnel syndrome; magnetic resonance imaging; palmar flexor bowing of flexor retinaculum; pain severity.

Effect of splinting and exercise on intraneural edema of the median nerve in carpal tunnel syndrome—an MRI study to reveal therapeutic mechanisms

“…8 Signal intensity was calculated at three levels: (i) at the distal radioulnar joint where the pronator quadratus muscle was visible over the whole width of the radius (inlet of the carpal tunnel), (ii) at the center of the pisiform bone (mid-tunnel), and (iii) at the hook of hamate (outlet of the carpal tunnel). 9 Palmar bowing of the carpal ligament is also increased in CTS 29,30 and is considered an indirect measure of increased carpal tunnel pressure. 2,11 MRI scans were analyzed by drawing a straight line between the hook of hamate and the trapezium (H-T line) using ImageJ software (Version 1.44 g, National Institutes of Health, Bethesda, MD).…”

“…The bowing ratio of the ligament was defined as the perpendicular distance from the apex of the ligament to the H-T line divided by the length of the H-T line. 29 Since ligament bowing at the pisiform level has previously been shown to be normal in CTS, ligament bowing was only established at the level of the hook of hamate. 31 All MRI scans were coded and an investigator blinded to the group allocation took all measurements (AS).…”

Oxidative stress in subsynovial connective tissue of idiopathic carpal tunnel syndrome

“…34 A recent radiologic/MRI study showed that palmar bowing of the flexor retinaculum (a marker of tenosynovial edematous swelling) is related to the subjective symptoms of CTS. 35 In another pathologic study, the subjective symptoms were associated with MMP-2 activation and angiogenesis at the flexor tenosynovium. 2 Our study shows that a significant positive correlation exists between the subjective symptom severity of CTS and the immunoreactivities of eNOS and NF-␤, which suggests that oxidative stress in subsynovial connective tissues contributes to the subjective symptoms.…”

High-Resolution Imaging of Upper Limb Neuropathies

“…34 The diagnostic yield is higher when combined with secondary findings such as muscular denervation change, bowing of the flexor retinaculum, and flattening of the median nerve compared with the nerve proximal to the carpal tunnel. [34][35][36][37][38] MRI is an excellent tool to evaluate muscular denervation changes. This was used prior to direct high-resolution MRI for primary evaluation of the peripheral nerves.…”