["Skip lesions" in neurological deficits caused by tethered cord syndrome]

The neurological deficits caused by tethered cord syndrome do not necessarily follow a dermatomal pattern of the affected spinal cord from caudal to cephalic fashion. The authors defined these neurological deficits as "skip lesions", and reviewed the neurological deficits in tethered cord syndrome. Among 29 cases, inconsecutive segmental motor weakness in 3 cases, inconsecutive segmental sensory impairment in 6 cases, positive Babinski reflex in 8 cases, supranuclear neurogenic bladder in 3 cases and lumbago or leg pain in 4 cases were observed and they were thought to be compatible with the neurological deficits called "skip lesions". The basic mechanism of this sign is that the cephalic portion of the spinal cord is functionally impaired during flexion of the lumbosacral spine, while the caudal spinal cord with decreased visco-elasticity dose not elongate. Inconsecutive motor-sensory disturbance, accelerated deep tendon reflexes in the lower extremities, positive Babinski or other pathological reflexes in the lower extremities, uninhibited neurogenic bladder, lumbago and pain in the legs were considered to belong to the category of "skip lesions" and they can be treated by the untethering procedure. The authors concluded that preoperative careful insight into the mechanism of "skip lesions" revealed surgical efficacy for the reversible neurological deficits by the untethering procedure, or the efficacy of decompression of the lipoma or neurolysis around the involved spinal nerve roots.