AAHS ASPN ASRM - 2013 Annual Meeting - American Association ...

ASPN Scientific Paper Presentations A
A Method for Preoperative Evaluation of Brachial Plexus Birth Injuries
Institution where the work was prepared: Miami Children's Hospital, Miami, FL, USA
Ilker Yaylali, MD, PhD; Israel Alfonso, MD; John. A. I. Grossman, MD; Miami Childrens Hospital
Objective:
To describe and report the results of a new technique to evaluate the severity of brachial plexus birth injuries.
Background:
Currently, preoperative clinical examination is the only method to select candidates for early brachial plexus reconstruction surgery after birth injury. Stimulation
of the cervical spinal cord activates the corresponding á-motoneurons thus producing compound muscle action potential (CMAP). This technique allows assessment
of nerve conduction velocity and amplitude of CMAP.
Method:
The spinal cord is stimulated from the surface by placing an electrode (anode) midline at the level of the 5th cervical spine apophysis; and the cathode on the
lateral surface of the neck at the same level. The stimulation is performed using 100 mAmps for 0.2 ms. CMAPs were recorded from the supraspinatus, deltoid,
biceps, and triceps muscles. Axonal loss was calculated by the following formula: 100 – (injured side amplitude/healthy side amplitude) X 100. Myelin
loss was calculated by: 100 – (healthy side conduction velocity/ injured side conduction velocity) X 100. The average combined axonal and myelin loss was
calculated by adding axonal and myelin loss from each muscle and dividing by 8.
Material:
We studied 66 infants (36 female, 30 male) with brachial plexus birth injuries. Mean age at the time of evaluation was 6 months. Every infant underwent a
clinical evaluation at the time of the study. Fifty patients were selected for surgery based on the clinical evaluation. All operated cases had significant nerve
disruption. Results: The average combined axonal and myelin loss in patients who underwent surgery was 47.98% (sd 24.1%) and 20.18% (sd 12.3%) in
patients not requiring surgery. Average combined axonal and myelin loss was significantly different between surgical and nonsurgical cases (p