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 Spinal Cord Ischemia Associated with High Aortic Clamping: Methods of Protection

1. Anatomy of the blood supply to the spinal cord

2. Pathophysiology of spinal cord ischemia and reperfusion

  • Hemodynamic changes.
  • Ischemic injury.
  • Reperfusion injury.
  • Delayed onset paraplegia.

3. Methods of protection

  • Experimental results of spinal cord protection (including the role of cerebrospinal fluid drainage, systemic hypothermia, hypothermic perfusion, regional cooling, barbiturates, superoxide dismutase, calcium channel blockers, prostaglandins, papaverine, MK-801, monoclonal antibodies, fluosol-DA, opiate antagonists, aminosteroids).
  • Clinical results of spinal cord protection (including the role of aortic cross-clamp time, reimplantation of intercostals arteries, bypass or shunt, evoked potentials, spinal fluid drainage, hypothermia).

References

Huynh TT, Miller CC 3rd, Safi HJ. Delayed onset of neurologic deficit: significance and management. Semin Vasc Surg 2000;13:340-4.

This review discusses the significance and management of delayed-onset neurologic deficit. The pathophysiology of delayed-onset neurologic deficit after thoracoabdominal aortic aneurysm repair, the various factors known to increase the risk of spinal cord ischemia, as well as the different intraoperative adjuncts to improve spinal cord protection are presented.

Cambria RP, Davison JK. Regional hypothermia with epidural cooling for spinal cord protection during thoracoabdominal aneurysm repair. Semin Vasc Surg 2000;13:315-324.

The authors present a method for providing regional cord hypothermia with epidural cooling during TAA repair. Technical considerations with epidural cooling and the clinical results obtained in their experience are discussed.

Coselli JS, LeMaire SA, Schmittling ZC, Koksoy C. Cerebrospinal fluid drainage in thoracoabdominal aortic surgery. Semin Vasc Surg 2000;13:308-314.

The purpose of this randomized clinical trial was to evaluate the impact of cerebrospinal fluid drainage (CSFD) on the incidence of spinal cord injury after extensive thoracoabdominal aortic aneurysm (TAAA) repair. Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits. The authors conclude that perioperative CSFD reduces the rate of paraplegia after repair of extent I and II TAAAs.

de Haan P, Kalkman CJ, Jacobs MJ. Pharmacologic neuroprotection in experimental spinal cord ischemia: a systematic review. J Neurosurg Anesthesiol 2001;13:3-12.

In this article, the literature on pharmacological neuroprotection in experimental SCI is systematically reviewed to assess the neuroprotective efficacy of the various agents. The results suggest that numerous agents may protect the spinal cord from transient ischemia. However, poor temperature management and lack of statistical power severely weakened the evidence. The authors conclude that clinical evaluation of pharmacological neuroprotection in surgical procedures that carry a risk of ischemic spinal cord damage is not justified on the basis of this analysis.

Robertazzi RR, Cunningham JN Jr. Intraoperative adjuncts of spinal cord protection. Semin Thorac Cardiovasc Surg 1998; 10:29 -34.

After a brief discussion of the etiology of spinal cord ischemia, the authors present several intraoperative interventions and strategies, which address the multifactorial nature of cord injury. The role of adequate distal aortic perfusion, cerebrospinal fluid drainage, pharmacological agents such as papaverine and steroids, as well as the role of circulatory arrest and profound hypothermia are analyzed.

Posted June 2010