Somatosensory evoked potentials as a means of assessing neurological abnormality in congenital talipes equinovarus

Somatosensory evoked potentials (SSEPs) are a very sensitive measure of the functional integrity of the neuroaxis, including peripheral and central structures. When used in diagnostic mode they can provide additional information regarding the probable areas of dysfunction. SSEPs were recorded from 44 children (64 feet with congenital talipes equinovarus, CTEV), between the ages of 2 to 15 years, who had structural CTEV deformity previously treated by surgery, with no clinical evidence of neurological deficit. SSEPs were elicited after sequential and bilateral stimulation (0.1 ms/5 Hz/10 to 20 mA) of the posterior tibial nerve and the common peroneal nerve and were recorded cortically (P40). In half the children, additional recordings were conducted at the knee (N5), the first lumbar spinous process (N14), and the seventh cervical spinous process (N20). Eighteen children had abnormal responses, four children had non-reproducible responses, and 22 children had normal responses. Analysis of the data at different levels of the nervous system showed that eight children had abnormality at the spinal level. The surgical outcome was influenced by the neurological abnormality, with an excellent or good outcome in 34 of 36 feet with normal neurology and 19 of 28 feet where a deficit was present (p<0.05). These findings support the neurological theory as an etiological factor in CTEV deformity.