Comparative analysis of ultrasound and electrophysiological studies in mild ulnar neuropathy at the elbow

Introduction. Nerve conduction study (NCS) is the main component of instrumental diagnostics of ulnar neuropathy at the elbow (UNE). In recent years, ultrasound (US) examination has become increasingly important, allowing the identification of the site of compression, dynamic examination, and assessment of the structures surrounding the nerve. Aim. To compare the results of NCS and US in patients with clinical signs of UNE. Materials and methods. The NCS and US data were analyzed in 93 patients with clinical signs of mild (86 patients) and moderate (7 patients) UNE. Standard NCS studies and US of the ulnar nerve were analyzed. Results. Electrophysiological changes corresponding to UNE were detected in 48 (51.5%) examined patients, ultrasound changes in 50 (54%). The groups with positive and negative NCS and US results did not differ in the main anthropometric characteristics and disease duration. When the left ulnar nerve is involved, nerve conduction study and ultrasoun are often positive; the presence of m. anconeus epitrochlearis in the retroepicondylar groove is often accompanied by negative nerve conduction study results. The ulnar nerve CSA is characterized by an inverse correlation with the amplitude of the ulnar nerve sensory response, motor nerve conduction velocity at the elbow and compound muscle action potential amplitude recorded from abductor digiti minimi muscle. The maximum ulnar nerve CSA at the elbow differs in patients with different UNE severity (p = 0.0001). Conclusions. In the group of patients, which was characterized by a predominance of patients with mild cubital tunnel syndrome, NCS and ultrasound results are highly consistent. The identified factorial interactions indicate the need for a comprehensive approach to diagnosing ulnar nerve lesions, taking into account the lateralization of the process and the specific anatomical features.

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