Neural activity generated in the neural placode and nerve roots in the neonate with spina bifida.

Object: The authors conducted a study to determine the neurophysiological capacity of the neural placode in spina bifida neonates and to determine if the spinal nerve roots in these neonates had normal stimulation.

Methods: The authors present a case series of 2 neonates born with open neural tube defects who underwent neural tube closure within 24 hours of birth. Neurophysiological monitoring and electrical stimulation of the placode and nerve roots was performed before and after closure of the neural tube.

Results: Stimulation of nerve roots resulted in evoked electromyographic responses in distinct muscle groups, indicative of the myotome innervation pattern. Stimulation threshold did not change significantly after closure of the placode. Stimulation within the placode generated an alternating pattern of activity in the left and right legs.

Conclusions: Closure of the neural tube did not affect the stimulation threshold of the nerve roots, which remained easily excitable. The viability of the nerve roots suggests that they may be candidates for neural prostheses in the future. The neural placode contains basic neural elements for generating a locomotor-like pattern in response to tonic neural inputs.