The Role Of Ultrasonography In Diagnosis Of Carpal Tunnel Syndrome And Its Clinical Classification

ObjectiveComparing the physical measurement with Preoperative ultrasonography，In order to specifythe reliability of ultrasonography (US)in measuring the median nerve at carpal canal.Toprobe the role of ultrasonography in the diagnosis of carpal tunnel syndrome(CTS) anddistinguishing the clinical classification of CTS.MethodsFrom Oct,2011to Mar,2013,There were seventy patients according with the program ofclinical classification of CTS and therapy(table1) in all that were dignosed by our hospital, Thepatients were classified into mild,moderate and severe set(thirty wrists each).Those patients werediagnosed by US to measure the flattening of the median nerve was as calculated as the ratio ofthe nerve’s major to its minor axis(flattening ratio) and the thickness of the flexor retinaculam,flattening ratio is calculated as the ratio of the major to its minor axis. The medium and heavypatients were treated by operation, while the above-mentioned values could be measured byvernier caliper. The results in before and after operation were compared with t-test in order tospecify the reliability of US in measurement of median nerve.Fifty persons without CTS had the same age and gender with the illness group. All thoseabove-mentioned values were measured by US, the illness group and control group were drawnby the ROC curve to define the threshold value of CTS and study the role of US applied in CTS.The diagnosis threshold value in different classification of CTS was defined by ROC inillness group including light, medium and heavy set, The sensitivity and specificity of clinicalclassification in CTS was revealed through measuring the median nerve and the thickness of theflexor retinaculam by US. ResultUltrasound measurement of carpal tunnel syndrome the median nerve of the flat rate and thethickness of the transverse carpal ligament surgery vernier caliper measurement results compared,no significant difference (P>0.05), ultrasound measurement of the median nerve and thetransverse carpal ligament to have higherreliability.The shape of the median nerve could be revealed directly by Ultrasonography．In mostcases，the hook of the hamate bone was compressed．Another common site was the pisiformbone．Sometimes both two sites could be compressed at the same time．The length of compressednerve was not the same．The nerve flattened at the point compressed，with the proximal nervemostly swelled and the distal nerve thickned ordinarily. Comparison with the data of the controlgroup proved that the quantitative criterias including the flattening ratio at the pisiform bone，thethickness of the flexor refinaculum and the flattening ratio at the hook of the hamate bone weresignificant. ROC showed the cut-off of these criterias were≥2.535，≥0．3cm and≥3.225.According to these cut-off values．Their diagnostic sensitivity were93.3％，94.4％and87.7％respectively, the corresponding specificity were62.0％，90.0％and72.0％．The thickness of theflexor refinaculum and the flattening ratio at the hook of the hamate bone were two highlysensitive and specific criterias.The difference between moderate and severe groups was not statistic significant．Whiledifference between the mild group and the moderate-severe one had statistic significance. Thequantitative criterias including the flattening ratio at the pisiform bone，the thickness of theflexor refinaculum and the flattening ratio at the hook of the hamate bone were significant. ROCshowed the cut-off of these criterias were≥2.92，≥0．43cm and≥3.48. According to thesecut-off values．Their diagnostic sensitivity were85.0％，51.67％and86.67％respectively, thecorresponding specificity were43.3％，90.0％and76.67％．The flattening ratio at the hook ofthe hamate bone was the highly sensitive and specific criterias.ConclusionUltrasonography could not only detect the pathological nerve from its shape，but alsodetermine the existence of CTS by quantitatived iagnostic criterias. Also auxiliary diagnostic significance for carpal tunnel syndrome in patients with Clinical classification, which provides anew reference for the clinical treatment of choice.