Onabotulinum toxin type A injection into the triceps unmasks elbow flexion in infant brachial plexus birth palsy

Abstract

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.

The Effectiveness and Safety of Botulinum Neurotoxin in Obstetric Brachial Plexus Injury: A Systematic Review and Meta-Analysis

“…We identified 49 articles in the initial search, of which 13 met our inclusion criteria ( Figure 1 ), including 11 case series [ 10 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ] and 2 cohort studies [ 40 , 41 ]. Overall, 347 patients with OBPI were treated with BoNT.…”

“…Out of the 13 included studies, 2 studies did not report their participants’ operation history before BoNT injection [ 32 , 35 ] and 6 studies did not report average dose of BoNT injection [ 10 , 34 , 35 , 36 , 37 , 39 ]. The operation history means any sort of surgery intended to relieve the symptoms of OBPI done before the trials.…”

“…Hence, they scored high risk of bias for not clearly reporting the clinical information of participants. Four articles did not clarify the last time of outcome measurement after BoNT injection [ 36 , 37 , 39 , 40 ]. The four articles had different last follow-up time points for each individuals, and they only reported the mean of the last follow-up time.…”

“…Two studies [ 36 , 39 ] reported the Toronto score for active elbow flexion. No significant improvement in active elbow flexion was found after BoNT, and the heterogeneity reached statistical significance (SMD, 1.099; 95% CI, −0.053 to 2.252, I 2 = 71.3%; Figure 7 ).…”

“…No significant difference were found in the deltoid (SMD, 0.675; 95% CI, −0.599 to 1.949, I 2 = 50.8%; Figure 8), biceps brachii (SMD, 0.225; 95% CI, −0.633 to 1.083, I 2 = 26.2%; Figure 9), and triceps brachii (SMD, 1.354; 95% CI, −1.493 to 4.202, I 2 = 90.8%; Figure 10) after BoNT. Two studies [36,39] reported the Toronto score for active elbow flexion. No significant improvement in active elbow flexion was found after BoNT, and the heterogeneity reached statistical significance (SMD, 1.099; 95% CI, −0.053 to 2.252, I 2 = 71.3%; Figure 7).…”