Department of Radiology, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, Iran.
Arch Iran Med. 2010 Nov;13(6):516-21.
Carpal tunnel syndrome is a common peripheral entrapment neuropathy. The purpose of this study is to determine whether high resolution ultrasonography can be an alternative diagnostic method to nerve conduction study in grading the severity of carpal tunnel syndrome.
A total of 164 wrists of 82 patients, bilaterally, were enrolled in the study. The cross-sectional area of the median nerve at the carpal tunnel inlet and outlet was measured in all patients with electrophysiologically confirmed carpal tunnel syndrome. All patients had nerve conduction study performed one week before ultrasonography. Then, comparisons between ultrasonography and nerve conduction study were made. The grading severity according to nerve conduction study was used as a gold standard reference.
The mean median nerve cross-sectional area at the tunnel inlet was 11.4±1.7 mm² for the carpal tunnel syndrome affected wrist and 5.78±0.9 mm² for the normal wrist (P<0.001). The mean median nerve cross-sectional area at the tunnel outlet was 9.9±1.2 mm² for the affected wrist with carpal tunnel syndrome and 4.7±0.7 mm² for the normal wrist (P<0.001).The best cutoff value of cross-sectional area at the tunnel inlet and outlet was 8.5 mm². The difference in cross-sectional area of the median nerve in mild, moderate and severe carpal tunnel syndrome was not statistically significant (P=0.2) neither in the carpal tunnel inlet nor outlet.
Based on this study, cross-sectional area of median nerve ultrasonography has a diagnostic value to confirm or exclude carpal tunnel syndrome, but could not be used for grading its severity.
腕管综合征是一种常见的周围神经嵌压性疾病。本研究旨在确定高分辨率超声是否可以替代神经传导研究，作为一种分级腕管综合征严重程度的诊断方法。
本研究共纳入 82 例双侧患者的 164 只腕关节。所有电生理确诊为腕管综合征的患者均测量正中神经在腕管入口和出口处的横截面积。所有患者在超声检查前一周均进行神经传导研究。然后，比较超声和神经传导研究。根据神经传导研究进行分级严重程度作为金标准参考。
腕管综合征受累腕关节的隧道入口处正中神经横截面积为 11.4±1.7mm²，正常腕关节为 5.78±0.9mm²（P<0.001）。腕管综合征受累腕关节的隧道出口处正中神经横截面积为 9.9±1.2mm²，正常腕关节为 4.7±0.7mm²（P<0.001）。隧道入口和出口处横截面积的最佳截断值为 8.5mm²。轻度、中度和重度腕管综合征患者正中神经横截面积的差异在入口和出口处均无统计学意义（P=0.2）。
基于本研究，正中神经超声横截面积具有确认或排除腕管综合征的诊断价值，但不能用于分级其严重程度。
