Routine shoulder ultrasound seen as appropriate for infants with brachial plexus birth palsy

Kevin Little, MD

Progressive shoulder dysplasia in the setting of neonatal brachial plexus palsy has been characterized for more than a century. When this process is encountered in the first year of life, it is termed “infantile dislocation” or “infantile dysplasia” of the glenohumeral joint, which portends more severe consequences in terms of shoulder function and motion. Consequently, the accurate diagnosis of infantile dysplasia is important to guide early interventions to maintain glenohumeral joint congruity and, thus, improve shoulder function. 

This study by Bauer and colleagues expands upon the existing literature regarding which patients will benefit from shoulder ultrasound. Their study demonstrated that 29% of patients in their tertiary referral center brachial plexus clinic had ultrasound findings of glenohumeral dysplasia, defined as an alpha angle of greater than 30° and a PHHD greater than 50%. While this is greater than the initial incidence of 8% noted by Moukoko and colleagues, it is consistent with more recent data presented by Pöyhiä and colleagues, who noted a 30% incidence in their population.

The diagnosis of infantile dysplasia was additionally most common between the 3rd and 6th months of life. Most importantly, this study provides a guide for clinicians to evaluate children with suspected glenohumeral dysplasia. Using a receiver operating characteristic curve, they demonstrate that, in patients with less than 60° of passive external rotation in shoulder adduction, ultrasound showed a sensitivity of 94% and a specificity of 69% for the diagnosis of glenohumeral dysplasia. 

Consequently, it should be the standard practice for clinicians to perform serial examinations (every 3 months or more frequently if deemed necessary) in children with unresolved neonatal brachial plexus palsy, especially during the critical period between the third and sixth month. Any patient with less than 60° of passive external rotation should obtain a dynamic shoulder ultrasound, preferably by an experienced technologist and musculoskeletal radiologist, in both internal and external rotation to fully evaluate the glenohumeral joint for dysplasia. This will help guide appropriate treatment to provide the best chance at maximizing shoulder function for these patients.

References:

Fairbank HAT. Lancet. 2013;doi:10.1016/S0140-6736(00)52017-0.

Moukoko D, et al. J Bone Joint Surg Am. 2004;86 (4):787-793.

Pöyhiä TH, et al. Radiology.2010;doi:10.1148/radiol.09090570.

Waters PM, et al. J Bone Joint Surg Am.1998;80(5):668-677.