Association Between Shoulder Subluxation and Surgical Intervention in Birth Brachial Plexus Palsy

Background and/or Objectives: To examine the association between shoulder subluxation and primary and secondary surgical interventions in birth brachial plexus palsy.

Design: retrospective cohort

Setting : Multidisciplinary Brachial Plexus Clinic in tertiary care hospital

Participants : 114 patients undergoing screening ultrasound for shoulder subluxation at 3 months of age

Interventions: not applicable

Main Outcome Measures: ultrasound alpha angle, passive range of motion external rotation (PROM-ER), Active Movement Scale score for external rotation (AMS-ER), intervention with onabotulinum toxin injections and casting (BTX-cast), surgical intervention with nerve reconstruction and/or tendon transfer

Results: Of the 114 patients undergoing screening shoulder ultrasound, 98 patients (86%) had shoulder subluxation. 59% had alpha angle ≥ 40 degrees, which is the institutional criteria for intervention with BTX-cast to correct subluxation. Among the 98 patients with shoulder subluxation on initial screening, 30 went on to have nerve reconstruction and 27 underwent tendon transfer. This was notably higher compared to patients without subluxation on initial screening ultrasound, of which only 4 had nerve reconstruction and 2 had tendon transfer. In the cohort who underwent BTX-cast, 52% went on to require surgical intervention and had worse PROM-ER and AMS-ER compared to those who did not undergo BTX-cast

Conclusions: Shoulder subluxation in birth brachial plexus injuries is associated with worse PROM-ER and AMS-ER scores. If shoulder subluxation is severe enough to require treatment with BTX-cast, then the patients are more likely to undergo surgical intervention in the future. Further research is needed to understand the predictive factors for interventions.