Abstract
Carpal tunnel syndrome is a compression neuropathy of the median nerve at the wrist. Deviated wrist posture has been linked to work-related carpal tunnel syndrome, yet it is unclear how posture changes carpal tunnel (CT) size and shape. In addition, it is not clear how these factors contribute to median nerve compression. PURPOSE: 1) to evaluate errors associated with 3D reconstruction from MR images and 2) to develop individual models to predict posture-related changes in CT volume. METHODS: Axial MR images were used to create wrist models of 6 individuals. Each carpal tunnel was modeled as a modified cylinder consisting of two surfaces; one for the carpal arch and one for the transverse carpal ligament (TCL) and flexor retinaculum complex. Carpal bone motions were applied to the CT surfaces to predict changes in tunnel dimensions and orientation with wrist deviation relative to neutral (30° flexion to 30° extension). RESULTS: “Land marked” volumes, those contained by the anatomical boundaries of the CT, were significantly smaller than volumes reconstructed directly from MRI in all postures (by an average of 977 mm3). Land marking improved the between-individual consistency of measurements, and suggested that previous studies may have overestimated CT volume by as much as 20–30%. Comparison of internal and external measures, in the neutral posture, revealed that land marked volume and average cross-sectional area were more closely related to wrist width (adjusted R2 of 0.76 and 0.88, respectively) than wrist circumference (adjusted R2 of 0.25 and 0.19, respectively). Model predicted volumes were not significantly different than land marked volumes determined from MRI reconstruction (6% decreases in flexion and extension). CONCLUSION: These data suggest posture-related changes in CT volume are likely not sufficient to explain CT pressure changes with wrist posture, and support incorporation of carpal tunnel contents. Supported by NSERC grant #217382.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
