MONITORING OF THE MOTOR PATHWAY DURING SPINAL SURGERY

Paraplegia caused by irreversible lesions of the spinal cord is one of the major possible complications after scoliosis surgery. Several mon itoring methods have been proposed but none are completely satisfactor y. Since 1986 the authors assessed motor pathways during scoliosis sur gery, using electrical stimulation of the motor cortex and lower limb muscle recordings (tibialis anterior muscle). Twenty-seven patients we re included in this study: 25 with idiopathic scoliosis and 2 with dor sal kyphosis. Recordings in anesthetized patients with hypothermia wer e performed before and after spinal derotation during the surgical pro cedure. Magnetic cortical stimulation was carried out in ten awake pat ients before and after surgery. Reproducible responses were obtained i n 22 patients under anesthesia. In eight patients no difference of the latency of the muscle response was detected before and after the corr ection of the spinal angulation. In 14 patients the increase of latenc y ranged from 0.4 ms to 5.2 ms. No correlation was found between the s lowing of motor conduction and the magnitude of spine correction. No c entral neurologic complications were seen after surgery, The authors c oncluded that their study demonstrated that motor pathway assessment i n anesthetized patients can be performed at different times during the surgical procedure, This technique should help in the future monitori ng spinal function during scoliosis surgery.