Evaluation of the ulnar nerve with shear-wave elastography: a potential sonographic method for the diagnosis of ulnar neuropathy

Abstract

This study was designed to verify whether shear-wave elastography (SWE) can be used to differentiate ulnar neuropathy at the cubital tunnel from asymptomatic ulnar nerve or medial epicondylitis. An additional aim was to determine a cutoff value to identify patients with ulnar neuropathy. Methods: This study included 10 patients with ulnar neuropathy at the cubital tunnel as confirmed with electromyography (three women and seven men; mean age, 51.9 years), 10 patients with medial epicondylitis (nine women and one man; mean age, 56.1 years), and 37 patients with asymptomatic ulnar nerve and lateral epicondylitis (21 women and 16 men; mean age, 54.0 years). Each patient underwent SWE of the ulnar nerve at the cubital tunnel, distal upper arm, and proximal forearm. Results: Patients with ulnar neuropathy at the cubital tunnel exhibited significantly greater mean ulnar nerve stiffness at the cubital tunnel (66.8 kPa) than controls with medial epicondylitis (21.2 kPa, P=0.015) or lateral epicondylitis (33.9 kPa, P=0.040). No significant differences were observed between patients and controls with regard to ulnar nerve stiffness at the distal upper arm or the proximal forearm. A stiffness of 31 kPa provided 100% specificity, 80.0% sensitivity, 100% positive predictive value, and 83.3% negative predictive value for the differentiation between ulnar neuropathy and medial epicondylitis. Conclusion: Cubital tunnel syndrome is associated with a stiffer ulnar nerve than lateral or medial epicondylitis. SWE seems to be a new, reliable, and simple quantitative diagnostic technique to aid in the precise diagnosis of ulnar neuropathy at the cubital tunnel.

Post-Operative Assessment of Ulnar Nerve Tension Using Shear-Wave Elastography

“…ENMG allows the functional analysis of peripheral nerve conduction, and currently represents the key diagnostic modality, providing details about the degree of myelin dysfunction and axonal loss [ 13 ]. However, this examination also presents some disadvantages, as it is time-consuming, can be painful, and carries a risk of false negative results [ 4 , 10 ]. Magnetic resonance imaging (MRI) is another helpful tool to evaluate soft tissues and determine the location of the injury, but it gives no indication about the severity of a neuropathy, and can only be used to confirm the diagnosis [ 4 ].…”

“…High-resolution ultrasound imaging has gained attention recently as a complementary investigatory tool of the peripheral nervous system, as many clinically important nerves are located superficially and are easily accessible for this type of examination [ 10 , 13 , 14 ]. Conventional B-mode ultrasound can provide information regarding the site of the lesion, the eventual loss of the normal fascicular architecture, abnormal nerve cross-sectional areas (CSAs) or echogenicity, increased vascularity, reduced or excessive nerve mobility, or anomalous anatomical structures causing nerve injury [ 8 , 9 , 10 , 11 , 12 , 13 ]. In several previous studies, patients with ulnar neuropathy at the elbow have been shown to have an increased CSA when compared with healthy control groups, but the cutoff above which CSA is considered pathological varies between authors [ 2 , 3 , 4 , 5 , 15 , 16 ].…”

“…Therefore, patients with compressive neuropathy at the elbow have increased stiffness values in SWE, with the cutoffs varying from 31 kPa to 61 kPa [ 2 , 3 , 17 ]. Some authors believe that ultrasound, or more specifically SWE, will become part of the routine examination for the diagnosis of ulnar neuropathy at the elbow, in support of ENMG, or even alone [ 1 , 2 , 3 , 5 , 8 , 10 , 17 , 18 ].…”

“…Shear-wave elastography (SWE) is a recently developed ultrasound imaging technology that provides quantitative values of soft tissue stiffness, including in the muscle, tendon and nerve. It improves the diagnostic performance of ultrasound imaging for various neuropathies involving the median, sciatic, tibial and ulnar nerves [ 10 ]. This technique may find application for surgeons as an instrument to detect when peripheral nerves are exposed to mechanical overload after nerve transposition or end-to-end neurorrhaphy.…”

Diagnosis of ulnar nerve entrapment anterior to the medial epicondyle by ultrasound elastography and diffusion tensor imaging with fiber tractography: a case report

“…However, electroneuromyography also has some disadvantages as it is time consuming, can be painful, and has a limited sensitivity. High-resolution ultrasound imaging has gained attention recently as a complementary diagnostic test for peripheral nerve injuries [ 9 ]. Conventional ultrasound can provide information about the anatomical site of the lesion and changes in morphology and echogenicity of the nerve: loss of the nerve’s normal fascicular architecture, and increased/decreased nerve CSA or echogenicity in B-mode; increased nerve vascularity in color Doppler; and abnormal anatomical structures (e.g., accessory muscle) causing nerve injury [ 9 ].…”