Clinical neurophysiological assessment of children with sacral anomalies

Clinical neurophysiological investigations were carried out in 8 children with various forms of sacral dysplasia. No EMG activity was found in leg muscles in two children with complete sacral agenesis, even though pelvic floor activity was preserved in one of these. The external anal sphincter and puborectalis were examined in all cases, and it was easy to demonstrate neuropathic changes in individual motor unit potentials by attenuation of their low frequency components. There was only a loose association between any pelvic floor neuropathy and the level of the bony defect in the sacrum, confirming recent reports. Trans-cutaneous stimulation of the spinal nerve roots in the lumbar canal was carried out in four children. Unilateral slowed conduction in L5 roots corresponded with the clinical signs in one patient, and absent innervation of leg muscles was confirmed in the two children with complete agenesis. Normal L1-L4 conduction times were found in a child with no clinical signs. Early assessment of children with sacral anomalies is important in order to prevent secondary complications. Clinical neurophysiological investigations are useful in delineating the different patterns of neurological involvement, especially in the pelvic floor, and the results complement those obtained with imaging techniques.