[Evaluation of ischemic injury of the spinal cord following endoprosthesis implantation in the thoraco-abdominal aorta on a rat model].

INTRODUCTION

Spinal cord ischemia is one of the most dreaded complication which may occur after conventional surgery of the thoraco-abdominal aorta, as well as following endoprostheses implantation. A better understanding of its pathogeny and physiopathology may lead to the introduction of means or measures for its prevention. The widespread utilization of the endovascular management of thoraco-abdominal aortic pathology stimulated the search for new alternatives to overcome the problem.

MATERIAL AND

METHODS

An experimental study was conducted, using Wistar-Lewis rats. Thirty-six animals were employed to assess the spinal cord consequences following the implantation of PTFE endoprosthesis in the thoraco-abdominal aorta. The endoprostheses were introduced through a distal aortotomy and advanced until the limits of the subclavian artery, down to the celiac axis. A similar group of animals underwent the conventional surgical management. To evaluate the neurologic repercussions, a sensor was placed in the spinal cord aimed at the registry of the bioelectric potentials, every two hours, until a limit of eight hours, in subgroups of six animals. Finally, the spinal cord was removed for histological examination.

RESULTS AND DISCUSSION: The collected data revealed that significant ischemic alterations occurred eight hours after the implantation of the endoprostheses and that 48 hours later some signs of recovery could be observed, probably by means of collateral blood flow arising from the spinal cord itself or from branches of the thoraco-abdominal vasculature. However, it must be stressed that these results were obtained in healthy animals, with normal arteries, and that the resistance of the nervous tissues to the ischemia is certainly lower than in individuals with previous arterial pathology.