A Systematic Review of the Electrodiagnostic Assessment of Neonatal Brachial Plexus Palsy

Figures

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  Figure 1:. Schematic of the brachial plexus anatomy.

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  Figure 2:. Representative images of the clinical appearance of neonatal brachial plexus palsy: A) mild, C5-C6 spinal nerve roots; B) intermediate, C5-C7 spinal nerve roots; C) severe, C5-Th1 spinal nerve roots (image adapted from [29]).

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  Figure 3:. Classification of brachial plexus injury based on pathological outcomes (modified from [12]).

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  Figure 4:. Schematic of electrophysiological response, A) Compound action potential (CAP) describing the parameters: amplitude (A), duration of the negative spike (D1), duration of the positive spike (D2), latency to the start of the potential from stimulus artifact (L1), and latency to peak potential (L2) and B) H-reflex, a late response measure when the stimulus directly stimulates the motor nerve fibers (adapted from [40]).

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  Figure 5:. Linear correlation of A) ulnar nerve motor nerve conduction velocity (r = 0.80, R2 = 0.91, CI = 0.71-0.84) and B) median nerve sensory nerve conduction velocity (r = 0.71, R2 = 0.50, CI = 0.58-0.80) with gestational age (adapted from) [30].

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  Figure 6:. Age-relationship of conduction velocity in injured brachial plexus. A) ulnar nerve conduction velocity and B) median nerve sensory nerve conduction velocity (adapted from [44]).

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  Figure 7:. Representative neonate electromyography recordings used to identify brachial plexus injury type by examining motor unit action potentials (adapted from [39]).

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  Figure 8:. Representative electrophysiological recordings in a 2-day old piglet of axonal denervation (adapted from [45]).

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  Figure 9:. Schematic of C5, C6, and C7 nerve roots (i.e., upper brachial plexus) innervation to the biceps muscle before and after injury of the neonate. A) Schematic showing the involvement of all the nerve roots (blue) to the biceps muscle at birth. B) Schematic showing damage to C5-C6 (red thunderbolt) nerve roots leads to zero to limited involvement of the C5-C6 motoneuron to the biceps muscle (grey) and central adaptation from C7 motoneuron pool (green) to the muscle biceps (modified from [47]).