The Value Of Ultrasonographic Measurements Of The Median Nerve In The Diagnosis Of Carpal Tunnel Syndrome: A Meta-analysis

Objective:Carpal tunnel syndrome(CTS)is the most common form of peripheral nerve entrapment,the main symptoms are numbness in the fingers and wrist swelling,conservative treatment can be choosed and the prognosis is pretty good if diagnosed early.If not promptly treated,CTS may cause permanent damage and greatly affect the work and life.The diagnosis of CTS is based mainly on patient's history,clinical findings and electrophysiological studies,and neural electrophysiological examination is accepted as the gold standard.Although electrophysiological examination often indicates the level of lesion,it does not provide spatial information about the nerve or its surroundings that could help in determining etiology and choosing different operative approaches.So imaging techniques have been shown to be of value in the diagnosis of carpal tunnel syndrome.Magnetic resonance imaging(MRI)is expensive,relatively time-consuming,and still not wildly available,although it has good correct discrimination of the soft tissue.In recent years,with the rapid development of ultrasonic technology,ultrasonography has become increasingly widespread in the field of musculoskeletal.High-resolution sonogtaphy has emerged as feasible,non-invasive imaging tool for diagnosing carpal tunnel syndrome.Many studies have been done to assess the value of quantitative sonograpgy in the diagnosis of CTS.These studies were mainly concerned with investigating the sonography features of median nerve in carpal tunnel,including increased cross-sectional area,median nerve swellingratioand,flattening ratio and so on.Most researchers used cross-sectional area as the evaluation parameter,but there are differences in the diagnostic accuracies reported.In this paper,evidence-based medicine methods have been employed to combine data from various articles published which studied on value of ultrasonographic measurements of the median nerve in the diagnosis of carpal tunnel syndrome.we gathered these information to assess the diagnostic accuracy of cross-sectional area measured by ultrasonography.Methods:Using "Carpal tunnel syndrome","ultrasonography"(or "sonography","ultrasound",et al)as key words,extensive literature search of Pubmed,Medline,the Cochrane Library,CNKI,Wanfang data,Weipu data from 1990 to 2016 were performed.Clinical trials in English and Chinese studying on ultrasonographic measurement of CSA in diagnosis of carpal tunnel syndrome were selected based on the inclusion criteria and exclusion criteria set in advance.Then qualities of the included articles were assessed using QUADAS tool.Subsequently,true positive number(TP),false positives number(FP),true negative number(TN),false negative number(FN)and information about background or design of the studies were appraised and extracted directly or indirectly.Software Stata 12.0 vision was used to perform all statistical analysis.Bivariate random effects model were chose.The heterogeneity of all included articles was tested using Q statistics and I2 statistics,and if there existed high heterogeneity,to explore the source of heterogeneity,meta-regression and subgroup analysis were conducted.Then the sensitivity,specificity,negative likelihood ratio,positive likelihood ratio,diagnostic odds ratio were summarized,summary receive operating characteristic(SROC)curve was drawn and calculate Area UnderCurve(AUC).Finally,Publication bias were judged by certain funnel plot using Deek's test.Results:Nineteen studies were selected meeting the inclusion criteria and exclusion criteria in this Meta-analysis,including 16 in English and 3 in Chinese.A total of 2640 subjects(number of wrists)enrolled,with 1575 in the case group(number of wrists),and 1065 in the control group(number of wrist).There existed high heterogeneity between the included studies(P=0.000,I2=95%,95%CI:92%-99%).The results of meta-regression and subgroup analysis indicated that the subjects in the control group were healthy wrist of patients with CTS or wrists of healthy people,the level and method of measuring cross-area of median nerve,whether the study was blinded,the number of subject,transducer frequency may all be related to the heterogeneity in this study.A pooled sensitivity of 0.88(95%CI0.83-0.91),a pooled specificity of0.88(95%CI0.81-0.93),a pooled positive likelihood ratio of7.6(95%CI4.6-12.3),a pooled negative likelihood ratio of0.14(95%CI0.14-0.19),a pooled DOR of 43.66(95%CI:25.26-75.47)were calculated by meta-analysis.The AUC were 0.93(95%CI0.91-0.95),which indicated that the diagnostic method was effective.The Deeks funnel plot demonstrated the publication bias may exist.Conclusion:Meta-analysis suggests that the sensitivity and specificity ofultrasonographic measurements of the median nerve in the diagnosis of carpal tunnel syndrome is fairly high.As a lower cost,non-invasive examination,ultrasonography can also provides spatial information of carpal tunnel.It is of some value in the diagnosis of CTS,and can be used as effective supplementary diagnostic method.However,uniform diagnostic criteria of ultrasonography in the diagnosis of CTS is not established until now,many factors may effects veracity of diagnosis such as the choice of research objects and the method of measurement.To explore further and confirm it's diagnostic value,as well as establish a certain diagnostic criteria,more supports from rigorously designed large-scale diagnostic tests are desired.