Therapy Modalities of Neonatal Brachial Plexus Palsy
The first known description of neonatal brachial plexus palsy (BPP) dates from 1779 when Smellie reported the case of an infant with bilateral arm weakness that resolved spontaneously within a few days after birth. In the 1870s, Duchenne and Erb described cases of upper trunk nerve injury, attributing the findings to traction on the upper trunk, now called Erb’s palsy (or Duchenne-Erb’s palsy). In 1885, Klumpke described injury to the C8-T1 nerve roots and the nearby stellate ganglion that now bears her name.
Many cases of BPP are transient, with the child recovering full function in the first week of life. A smaller percentage of children continue to have weakness leading to long-term disability from the injury. The mainstay of treatment for these children is physical and/or occupational therapy in concert with a regular home exercise program. A select few patients may benefit from surgical intervention in the early stages to improve innervation of the affected muscles. Others benefit from tendon transfers performed later to improve shoulder and (sometimes) elbow function.
Numerous other nonsurgical treatments, including electrical stimulation and botulinum toxin injections, also may prove effective in the treatment of children with BPP. In view of the variability in presentation, treatment options, and outcome measures, a multidisciplinary approach to the care of the infant with BPP is recommended.
Neuromuscular electrical stimulation
- Neuromuscular electrical stimulation (NMES) is used widely for children with BPP. NMES is a modality in which muscles are stimulated by pulsating alternating currents. The 2 main forms used are threshold and functional electrical stimulation (FES). The former can begin when the patient is young; it involves the application of low-frequency currents to the muscle. This technique has been reported to increase blood flow and possibly muscle bulk but has not been studied rigorously. FES involves stimulation with a higher-frequency current, causing the muscle to contract and the arm to move.
- The stimulator needs to be titrated with assistance from the child to allow for sufficient muscle contraction and the avoidance of pain. Many children can cooperate sufficiently with this procedure by age 3 years, and the technique is helpful in prompting weak muscles to contract in functional situations. NMES has been reported in the literature as useful for facilitating muscle contraction and is used widely to minimize atrophy of affected muscles. No large studies have been published on the use of NMES with BPP, and its effect on reinnervation is not clear.
Botulinum toxin A therapy
- Botulinum toxin A (BoNT-A) therapy is being used by several facilities to improve the flexibility of shoulder internal rotators. It is also used in the treatment of co-contractions, with the toxin administered to temporarily paralyze the functioning muscles/groups in order to allow weak muscles to become stronger. The usefulness of this intervention still is being studied.
- A retrospective cohort study by Michaud et al supported the effectiveness of BoNT-A therapy in neonatal brachial plexus palsy (BPP). The study involved 59 patients with the condition, who underwent a total of 75 injection procedures in 91 muscles and/or muscle groups. Results included improvements in ROM for active and passive shoulder external rotation following shoulder internal rotator injections. In 67% of patients who received triceps injections, active elbow flexion improved and was sustained after the toxin was no longer active, and in 45% of patients who were being considered for surgery, the operation was modified, postponed, or avoided, after BoNT-A treatment.