Idiopathic carpal tunnel syndrome：a saddle-spaded transverse carpal ligament and its ;significances / 中华放射学杂志

ABSTRACT

Objective To explore the MRI characteristics of saddle transverse carpal ligament (TCL)of patients with idiopathic carpal tunnel syndrome (CTS). Methods The clinical diagnosis of 21 cases of idiopathic CTS patients (22 wrists) were retrospectively analyzed and as the idiopathic CTS group. Thirty two patients without CTS symptoms or TCL and volar soft tissue lesions (33 wrist joints) were selected as the control group. Patients in two groups were both conducted with sagittal and axial MRI scan of wrist joint to observe the form of the TCL, determine whether the TCL saddle and calculate the TCL palmar concave curvature and the median nerve compression rate. The differences of the morphology of the TCL of patients in two groups were compared by Chi?square criterion, and the difference of the TCL palmar concave curvature were compared by non parametric test. The relativity of TCL palmar correlation concave curvature and compression ratio of the median nerve of patients with idiopathic CTS was evaluated by the Pearson correlation analysis.Results The sagittal plane of patients with idiopathic CTS was upper, saddle shaped TCL was dented to the palmar and the concave point most frequently located in the hamate hook. Thirty one patients were with saddle shaped TCL (20 patients with idiopathic CTS and 11 patients in the control group) and 24 patients were with non saddle shaped TCL (2 patients with idiopathic CTS and 22 patients in the control group) as the standard of saddle shaped TCL concave 0.25 mm and the difference of the morphology of the TCL of patients in two groups had statistical significance (χ2= 17.791, P<0.01). The median of TCL palmar concave curvature of patients with idiopathic CTS and patients in the control group was 8.49%and 0.00%, respectively, the difference of which was statistically significant (Z=-4.79, P<0.01). The level of the median nerve, the TCL palmar concave curvature [(7.88+4.28)%] and the median nerve compression rate [(39.36 + 19.43)% ] of patients with idiopathic CTS were positively correlated (r=0.714, P<0.01). Conclusions Saddle shaped TCL is the characteristic manifestation of patients with idiopathic CTS. The TCL sagittal concave palm and median nerve compression percentage rate are both helpful to the accurate diagnosis.