Abstract
We studied the protective effects of intrathecally administered lidocaine against
ischemic spinal cord injury during surgery. Seven patients (mean age 63.7 years, male:female
= 6:1) with descending thoracic aortic aneurysms underwent reconstructive surgery.
Following intrathecal lidocaine administration (10 ml), the operation was performed
under femorofemoral bypass with an oxygenator. The aorta was cross-clamped at the
distal end of the descending thoracic aorta and the proximal end of the lesions. The
cross-clamping time was 47.1 ± 23.3 minutes (mean ± SD). The operative procedure was
total replacement of the descending thoracic aorta in five cases and patch closure
in two. There were no operative deaths but paraparesis developed in two cases of total
replacement. Neurological deficit was transient and disappeared in one case. In the
other case, with 88 minutes of normothermic aortic cross-clamping, paraparesis gradually
improved but was persistent after 7 months of follow-up. Graft anastomosis at the
distal aortic arch was time consuming in this case and presumably caused prolonged
spinal cord ischemia. Intrathecal administration of lidocaine was likely to reduce
ischemic spinal cord injury and increase tolerance of the spinal cord to ischemia
caused by prolonged aortic cross-clamping. This method was considered to provide a
useful assistance to expand the safety limit of spinal cord ischemia in surgical reconstruction
of the descending thoracic aorta requiring aortic occlusion. Tissue protective effects
of intrathecal lidocaine administration may be further augmented by combining with
deep hypothermia.
