Carpal tunnel syndrome treatment and the subsequent alterations in tendon and connective tissue dynamics

Does endoscopic carpal tunnel release during distal radial fracture fixation improve outcomes? A randomized controlled trial

This study investigated the functional outcome of prophylactic carpal tunnel release during distal radial fracture fixation. A total of 60 patients undergoing anterior locking plate fixation for a distal radial fracture were randomized into two groups: one having prophylactic endoscopic carpal tunnel release and the other serving as a control. Functional outcomes were assessed using the Patient-Reported Wrist Evaluation, Quick Disabilities of the Arm, Shoulder, and Hand, EuroQol 5-Dimension 5-Level questionnaire, Boston Carpal Tunnel Questionnaire, Pain Numerical Rating Scale, grip strength and finger-to-palm distance over a 12-month period. The study found no significant differences in overall functional outcomes or complications between the groups.Level of evidence: I.

Grip Force Modulation on Median Nerve Morphology Changes

Compression on the median nerve can lead to carpal tunnel syndrome (CTS), and median nerve indicators measured from ultrasound images can be used for CTS diagnosis. The aim of this study was to investigate the relationship between grip force modulation and dynamic morphological changes of the median nerve. We used a digital grip dynamometer to measure grip force while simultaneously conducting ultrasound examinations. Ultrasound images were sampled for both the dominant and nondominant hands of all participants (n = 20) during a baseline condition at approximately 0% maximum voluntary force (MVF), during sustained grip force conditions at 25%, 50%, 75%, and 100% MVF, and during the return to a relaxed state (≈0% MVF) directly following each grip force condition. Regardless of hand dominance, grip force level, and grip force modulation, median nerve cross-sectional area (MNCSA) during the grip tasks was smaller relative to the initial baseline condition without grip force. With respect to shape change, the median nerve became more flattened, including increased longitudinal diameter (D1) and decreased vertical diameter (D2), when grip force was relaxed compared to the preceding sustained grip force condition for the dominant hand; however, there were no significant shape changes for the nondominant hand. As morphological changes to tissue result in strain, our results indicate that median nerve injury development may be associated with more hand usage (dominant hand, grip exertion, and grip force modulation), and further suggests the evaluative potential for median nerve dynamics within the carpal tunnel.

The median nerve´s system of connective tissue distal to the pronator teres to the carpal tunnel

BACKGROUND

Connective tissue serves a role beyond mere spatial filling. Furthermore, there is increasing evidence that connective tissue plays an important role in the pathogenesis of conditions such as carpal tunnel syndrome (CTS). According to our hypothesis, the median nerve (MN) is surrounded by a system of connective tissue distal to the pronator teres and extending up to, and including, the carpal tunnel.

METHODS

To visualize the connective tissue surrounding the median nerve, we dissected the forearms of 15 body donors from pronator teres to the carpal tunnel, created plastination slices stained with Periodic Acid-Schiff (PAS), and injected ink into the seen spaces. We verified our findings with a segmentational analysis of radiological data of 10 healthy individuals.

RESULTS

We macroscopically describe the median nerve´s system of connective tissue (MC) distal to the pronator teres and up to and including the carpal tunnel. This system creates, connects, and separates spaces. At least from the pronator teres to the carpal tunnel it also creates subspaces from proximal to distal. For the MC, we established a mean cross-sectional area of 153.1 mm2 (SD=37.15) in the carpal tunnel. The median nerve consistently resides at the center of this MC, which further connects to flexor muscles of the forearm, and to the radius bone. In the carpal tunnel, the MC creates subspaces inside. There, it also acts as the outermost internal layer enveloping flexor tendons, and the MN.

DISCUSSION

The term MC does not negate but orders the existence of other "connectives", like subsynovial connective tissue, endo-, epi- or perineuria, epimysia, periostea, or peritendinea, to a hierarchy related to the median nerve. Diseases of the MN are common. Knowing the anatomy of the MC and how it relates to MN function may help clinicians recognize and understand conditions like CTS.

Dynamic Ultrasound Assessment of Median Nerve Mobility Changes Following Corticosteroid Injection and Carpal Tunnel Release in Patients With Carpal Tunnel Syndrome

Decreased median nerve (MN) mobility was found in patients with carpal tunnel syndrome (CTS) and was inversely associated with symptom severity. It is unclear whether MN mobility can be restored with interventions. This study compared the changes in MN mobility and clinical outcomes after interventions. Forty-six patients with CTS received an injection (n = 23) or surgery (n = 23). Clinical outcomes [Visual Analogue Scale; Boston Carpal Tunnel Questionnaire (BCTQ), which includes the Symptom Severity Scale and Functional Status Scale; median nerve cross-sectional area; and dynamic ultrasound MN mobility parameters (amplitude, and R² value and curvature of the fitted curves of MN transverse sliding)] were assessed at baseline and 12 weeks after the interventions. At baseline, the BCTQ-Functional Status Scale and median nerve cross-sectional area showed significant inter-treatment differences. At 12 weeks, both treatments had significant improvements in BCTQ-Symptom Severity Scale and Visual Analogue Scale scores and median nerve cross-sectional area, but with greater improvements in BCTQ-Functional Status Scale scores observed in those who received surgery than in those who received injections. MN mobility was insignificantly affected by both treatments. The additional application of dynamic ultrasound evaluation may help to discriminate the severity of CTS initially; however, its prognostic value to predict clinical outcomes after interventions in patients with CTS is limited.