Finite Element Modeling of the Fingers and Wrist Flexion/Extension Effect on Median Nerve Compression

Abstract

Carpal tunnel syndrome (CTS) is the most common pathology among disorders of the peripheral nervous system related to median nerve compression. To our knowledge, there are limited data on the effect of tendon movement on median nerve compression. This study focuses on the understanding of the carpal syndrome by simulating the impact of tendons movement caused by fingers flexion by Finite Element Analysis. Therefore, such modeling is the step toward the development of a personalized technique for value determining median nerve compression. Open-source MRI of the human right hand was used to build patient-specific phalanges of the fingers. Carpal tunnel soft tissues were considered as hyper-elastic materials, while bone structures were considered as elastic ones. The final finite-element model had 40 solid bodies which contacted the joint. Results were obtained for four cases of wrist movements: finger flexion, hand flexion/extension, and wrist extension with subsequent by finger flexion. Compression of the median nerve ranged from 129 Pa to 227 Pa. The results show that compression of the median nerve occurs faster during wrist flexion than during wrist extension or finger flexion. A decrease in compression during finger flexion was noticed with wrist extension followed by finger flexion.

A coupled electro-mechanical approach for early diagnostic of carpal tunnel syndrome

“…Stress was obtained in the median nerve and tendons during finger flexion and during flexion and extension of the hand. The loads in the carpal tunnel caused by finger flexion and extension were shown to be lower than those caused by hand flexion and extension [50,78,79]. The tendons slide along the median nerve and barely press on the nerve when fingers are flexed.…”

“…[41] considered a 3D-printed scaffold for scapholunate ligament reconstruction. It is also good to look at the studies where researchers have created complex models of the carpal tunnel, tendons and fingers [40,43,46,50]. Mouzakis et.…”

“…[53,54] identified the tendon and median nerve properties as isotropic, non-linear, hyperelastic and described their mechanical behavior with Ogden model [55] and determined the parameters α and μ. Our previous work [50] also included modelling of the entire hand, including tendons, carpal tunnel, carpal bones and phalanges. At the same time, soft tissue materials have been defined by the Ogden model with parameters from Main et al study.…”