Comparison of ultrasound with electrodiagnosis of scapular winging: A prospective case control study

Objective: Compare high-resolution ultrasound (HRUS) and electrodiagnostic examination (EDX) in the diagnostic workup of patients with scapulae alatae.

Methods: 27 patients with scapulae alatae and 41 healthy subjects (HS) and underwent a standardized clinical examination (CEX), EDX and HRUS. We measured the thickness of the serratus anterior (SER), rhomboid major and trapezius muscles and the diameter of the long thoracic (LTN), dorsal scapular and spinal accessory nerves (SAN).

Results: Twenty patients showed medial winging and six patients showed lateral winging on CEX. One patient had both lateral and medial winging. In patients with medial winging, the SER muscle was thinner and the LTN diameter was larger on the symptomatic side compared with the asymptomatic side and with the dominant side in HS. In this group, both EDX and HRUS detected abnormalities of SER muscle/ LTN with sensitivity of 65%, and with specificity of 100% and 57%, respectively. EDX and HRUS detected abnormalities of the trapezius muscle/ SAN with sensitivity of 60% and 40%, and specificity of 91%, and 86 % a, respectively. There was no significant difference between the two methods.

Conclusion: HRUS can contribute to the diagnostic workup of scapulae alatae by demonstrating atrophy of muscles and enlargement in nerve diameter.

Significance: HRUS supplements EDX in the diagnostic workup of scapulae alatae.