Multimodal ultrasound evaluation of asymptomatic ulnar nerve dislocation at the cubital tunnel.

Background: Ultrasonography has received broad acceptance as an effective peripheral nervous imaging examination. Shear wave elastography (SWE) can quantitatively assess the stiffness of nerves; however, little research has been conducted on elastography for ulnar nerve dislocation. The purpose of this study was thus to investigate the characteristics of multimodal ultrasound, including high-resolution ultrasonography and SWE, for asymptomatic ulnar nerve dislocation at cubital tunnel. Methods: In this prospective cross-sectional study, 41 participants were recruited in Shandong Provincial Hospital Affiliated to Shandong First Medical University in July 2022. The inclusion criteria for participants were being in good health and being 18-60 years of age. Meanwhile, the exclusion criterion was a history of upper limb pain or fractures, peripheral neuropathy, or systemic or immunological diseases. Finally, 38 participants were enrolled. Two ultrasound doctors measured the maximum diameter, the maximum cross-sectional area (CSA), and the shear modulus of the ulnar nerve at the cubital tunnel independently. Another two ultrasound doctors determined whether dislocation was present during dynamic elbow flexion and extension and divided the elbows into a dislocation group and a control group. The descriptive statistics and independent sample Results: Ulnar nerve dislocation was observed in 15.8% (12/76) of the ulnar nerves. There was no significant difference in the maximum diameter between the dislocation group (0.194±0.022 cm) and the control group (0.181±0.023 cm) (t=1.888; P=0.063). The CSA and SWE of the ulnar nerve were 0.064±0.009 cm Conclusions: Multimodal ultrasound consisting of high-resolution ultrasonography combined with elastography can comprehensively and quantitatively evaluate the morphological changes and mechanical properties of the dislocated ulnar nerve and monitor disease progress.