Onabotulinum toxin type A injection into the triceps unmasks elbow flexion in infant brachial plexus birth palsy: A retrospective observational cohort study

• Published in: Medicine (Baltimore) 2020-08, Vol.99 (34), p.e21830-e21830
• Main Authors: Morscher, Melanie A., Thomas, Matthew D., Sahgal, Suneet, Adamczyk, Mark J.
• Format: Article
• Language: English
• Subjects: Arm; Botulinum Toxins, Type A - administration & dosage; Botulinum Toxins, Type A - therapeutic use; Child; Child, Preschool; Clinical Decision-Making; Elbow Joint - physiopathology; Follow-Up Studies; Humans; Infant; Injections, Intramuscular; Muscle, Skeletal - physiopathology; Neonatal Brachial Plexus Palsy - drug therapy; Neonatal Brachial Plexus Palsy - physiopathology; Neonatal Brachial Plexus Palsy - surgery; Neuromuscular Agents - administration & dosage; Neuromuscular Agents - therapeutic use; Observational Study; Range of Motion, Articular - drug effects; Retrospective Studies
• ISSN: 0025-7974; 1536-5964
• DOI: 10.1097/MD.0000000000021830

Brachial plexus birth palsy (BPBP) is a neurologic injury that can result in mild to full paralysis of the affected upper extremity. In severe cases, nerve surgery is often performed before age 1 year. Several studies report gains in elbow flexion with onabotulinum toxin type A (OBTT-A) injections to the triceps; however, its use in infants is not widely reported. The purpose of this study is to present our experience using these injections before 6 months of age to therapeutically unmask elbow flexion and diagnostically guide surgical decision making.This is a retrospective observational cohort study. The cohort included infants with BPBP who received OBTT-A injection to the triceps before age 6 months. Indications for the injections include trace elbow flexion and palpable co-contraction of the biceps and triceps. Elbow flexion was evaluated using the Toronto Test score. Therapeutic success was defined as an increase in post-injection scores. These scores were then used diagnostically as an indication for surgery if the infant did not achieve full elbow flexion by 8 months. A treatment algorithm for OBTT-A triceps injection was developed based on all treatment options offered to infants with elbow flexion deficits seen in the clinic.Of the 12 infants that received OBTT-A triceps injections, 10 (83%) had improved Toronto test elbow flexion scores post-injection. Gains in elbow flexion once attained were maintained. Of the 9 OBTT-A infants with at least 2 years follow-up, 4 achieved full elbow flexion without surgery; the remainder after surgery. No complications with OBTT-A injections were noted and patients were followed on average 6 years. The average age at time of injection was 4 months (range: 2-5 months). Compared to other treatments given, OBTT-A infants tended to present with more elbow flexion than the 4 infants requiring immediate surgical intervention and less elbow flexion than the 16 infants treated conservatively.OBTT-A injection to the triceps in infants with BPBP before 6 months of age therapeutically improved elbow flexion and diagnostically guided surgical decisions when full elbow flexion was not achieved by 8 months of age with no known complications.