Quantifying the Elasticity Properties of the Median Nerve during the Upper Limb Neurodynamic Test 1

Abstract

Background. The upper limb neurodynamic test 1 (ULNT1) consists of a series of movements that are thought to detect an increase in neuromechanical sensitivity. In vivo, no trail was made to quantify the association between the nerve elasticity and different limb postures during ULNT1. Objectives. (1) To investigate the relationship between nerve elasticity and limb postures during ULNT1 and (2) to investigate the intra- and interoperator reliabilities of shear wave elastography (SWE) in quantifying the elasticity of median nerve. Methods. Twenty healthy subjects (mean age: 19.9 ± 1.4 years old) participated in this study. The median nerve was imaged during elbow extension in the following postures: (1) with neutral posture, (2) with wrist extension (WE), (3) with contralateral cervical flexion (CCF), and (4) with both WE and CCF. The intra- and interoperator reliabilities measured by two operators at NP and CCF+WE and intraclass correlation coefficients (ICCs) were calculated. Results. The intraoperator ( ICC = 0.72 – 0.75 ) and interoperator ( ICC = 0.89 – 0.94 ) reliabilities for measuring the elasticity of the median nerve ranged from good to excellent. The mean shear modulus of the median nerve increased by 53.68% from NP to WE+CCF. Conclusion. SWE is a reliable tool to quantify the elasticity of the median nerve. There was acute modulation in the elasticity of the median nerve during the ULNT1 when healthy participants reported substantial discomfort. Further studies need to focus on the elasticity properties of the median nerve in patients with peripheral neuropathic pain.

In Vivo Effects of Joint Movement on Nerve Mechanical Properties Assessed with Shear-Wave Elastography: A Systematic Review and Meta-Analysis

“…The modified Downs and Black checklist score varied from 9 to 13. Five studies showed good quality (more than 11 points) [49,[52][53][54][55], and 11 showed fair quality (8-11 points) [36,37,50,[56][57][58][59][60][61][62][63]. None of the included studies scored below 9 points.…”

“…The characteristics of the 16 included studies are shown in Tables 2 and 3. In the upper extremity, the median nerve (MN) was assessed in six studies [36,37,55,[61][62][63], while the ulnar nerve (UN) was explored in three studies [37,57,60]. In the lower extremity, the sciatic nerve (SN) and the tibial nerve (TN) were evaluated in six studies [49,50,53,54,58,59] and four studies [36,52,54,56], respectively.…”

“…In the lower extremity, the sciatic nerve (SN) and the tibial nerve (TN) were evaluated in six studies [49,50,53,54,58,59] and four studies [36,52,54,56], respectively. The MN was most commonly imaged in the forearm [36,37,55,61,62], followed by the proximal elbow [36,37], and lastly at the carpal tunnel level [63]. The UN was evaluated in the elbow region in three studies [37,57,60], and one study also reported data at the forearm level [37].…”

Toward peripheral nerve mechanical characterization using Brillouin imaging spectroscopy

“…Nerve elasticity is a biologically important but understudied concept. This property refers to the ability of nerves to stretch and deform in response to mechanical stress while maintaining their function and structure 1 . Nerve elasticity is particularly important in the peripheral nervous system, where nerves are exposed to a wide range of mechanical stresses and strains as they traverse the body and in the setting of trauma 2 .…”

“…This property refers to the ability of nerves to stretch and deform in response to mechanical stress while maintaining their function and structure. 1 Nerve elasticity is particularly important in the peripheral nervous system, where nerves are exposed to a wide range of mechanical stresses and strains as they traverse the body and in the setting of trauma. 2 Nerves’ mechanical properties are also essential for research and development of neural grafts for peripheral nerve regeneration.…”