A systematic review of the methodology of sonographic assessment of upper limb activities-associated carpal tunnel syndrome

Background Various upper limb activities were speculated to be associated with the development of carpal tunnel syndrome (CTS). Nonetheless, there are currently no standardization on the uses of parameters in CTS assessments, nor are there any conclusive findings regarding the usefulness of various sonographic measurements in studies of different upper limb activities. In this review, we intend to evaluate the methodology of assessing Carpal Tunnel Syndrome (CTS) induced by upper limb activities with ultrasonographic technique and provide corresponding suggestions. Methods Clinical studies on the association between upper limb activities and prevalence of CTS using ultrasonography were recruited in a database research on the basis of a procedural selection criteria and reviewed. The following qualitative items were extracted: characteristics of studies, scanning methods, selection of sonographic parameters and related article findings. Results Eleven studies were qualified for this review. Three studies were computer keyboard typing-related, five studies were electronic device-related, and three studies were wheelchair-related. All sampled articles included cross-sectional area (CSA) at the pisiform level. The swelling ratio (SR) and flattening ratio (FR) at the hamate level are also used in most studies in addition to the CSA at the pisiform level. The effectiveness of such parameters are subjected to various confounding factors such as age, weight, BMI and wrist anthropometrics, suggesting CSA and SR with sufficient levels had significant values as sonographic parameters. Values of parameters were found affecting symptomatic signs and hand dominance. Conclusion Ultrasound scan is a suitable tool to assess the relationship between upper limb activity and CTS. CSA at the pisiform level, SR and the FR at the hamate levels are generally suitable in upper limb associated-CTS investigations. Specific study designs are required to eliminate different confounding factors accordingly.