High Resolution Ultrasound of Scapulae Alatae - a Prospective Case Control Study

Scapula alata, caused by disturbance in the scapulothoracic stabilizer muscles due to nerve injury, is a relatively rare but also underreported disease. It can lead to years of invalidity of the affected upper extremity, considerable pain and social and emotional consequences for the patients. Unrecognized and misdiagnosed scapula alata and, consequently, wrong or delayed treatment is a general problem in this patient group. Today the diagnosis is based on the clinical examination and the electrophysiological examination. One of the problems is that the electrophysiological examination in a fair part of the patients is not showing any pathology even though the history of the patient and the clinical evaluation are indicating scapula alata.

This study is a single-blinded, prospective, controlled multicentre study. The aim of the study is to investigate whether ultrasound can be used as a supplement to the electrophysiological examination when diagnosing scapula alata. Ultrasound will be used to visualize possible thickening of the cross-sectional area of nerves and the degree and pattern of muscle involvement in patients with scapula alata. By comparing measurements from scapula alata patients with the measurements from healthy controls, we are able to see if ultrasound can distinguish these two groups from each other. Furthermore, we will examine whether the ultrasound measurements correlate with the electrophysiological findings in patients and, when available, compare the ultrasound measurements of muscle thickness with MRI (magnetic resonance Imaging) findings. The use of ultrasound in scapula alata patients may help determine the presence and severity of a nerve lesion and the subsequent degree of muscle involvement and may therefore serve as a supplement to the clinical diagnosis.