Society of Cardiovascular Anesthesiologists

Literature Reviews

Cerebrospinal fluid drainage reduces paraplegia after thoracoabdominal aortic aneurysm repair: Results of a randomized clinical trial

Joseph S. Coselli, MD, Scott A. LeMaire, MD, Cüneyt Köksoy, MD, Zachary C. Schmittling, MD, and Patrick E. Curling, MD, Houston, Texas. J Vasc Surg 2002;35:631-9.

Reviewers: Skandan Shanmugan, Albert T. Cheung, MD
University of Pennsylvania
Philadelphia, PA

Paraplegia and paraparesis remain a frequent complication of thoracoabdominal aortic aneurysm (TAAA) repair and is associated with a mortality rate in the range of 50% to 100%. Strategies to decrease the risk of paraplegia include lower body perfusion with partial left heart bypass, deliberate hypothermia, neurophysiologic monitoring, and lumbar cerebrospinal fluid (CSF) drainage. The objective of lumbar CSF drainage is to improve spinal cord perfusion pressure by preventing the increase in lumbar CSF pressure that is associated with aortic clamping. The efficacy of lumbar CSF drainage for the prevention or treatment of postoperative paraplegia has been reported in the medical literature, but the clinical experience has been confined to isolated case reports or small clinical series. Previous randomized trials designed to test the efficacy of lumbar CSF drainage were inconclusive because of small sample size or suboptimal CSF drainage.

The prospective randomized clinical trial to determine the impact of CSF drainage on neurological deficits was confined to patients undergoing extent I or II TAAA repairs. The operative technique was standardized and conducted with moderate heparinization, mild hypothermia, partial left heart bypass, and reattachment of patent critical intercostal arteries. The study involved 145 patients and excluded patients with previous TAAA surgery, shock, or contradictions to spinal catheter placement. Of the 145 patients entered into the study, 76 (52.4%) were randomized to CSF drainage (CSFD). In the CSFD group, the CSF drain was inserted at the L3 or L4 intervertebral space via a Tuohy needle and CSF was drained for a CSF pressure that exceeded 10 mm Hg. No limitation in the amount of CSF that could be drained was imposed. The endpoints were death, paraplegia, and paraparesis. Neurological evaluation was performed daily until hospital discharge and deficits were scored according to the following scale: 1 = minimal or no motion; 2 = motion not against resistance or gravity; 3 = motion against resistance and gravity without ability to stand/walk; and 4 = ability to stand and walk with assistance. Scores of 1 or 2 were defined as paraplegia, while scores of 3 or 4 indicated paraparesis. The Fisher exact test and a Student t test were used to test for differences between the CSFD and control groups.

Paraplegia or paraparesis occurred in nine of the 69 patients (13%) in the control group compared two of the 76 patients (2.6%) in the CSFD group (P = .026), corresponding to an 80% reduction in the relative risk of postoperative neurological deficits in the CSFD group. Surgery performed without CSFD, total unprotected aortic cross clamp time (clamp time without left heart bypass), and total aortic clamp time were identified as risk factors associated with immediate postoperative paraplegia. Thirty-day mortality rates were 5.3% (four patients) for the CSFD group and 2.9% (two patients) for the control group (P = .68). Mortality rate for patients with deficits was 45.5% and approximately 10 times greater than for those without deficits (4.5%; P = .0003). The CSFD and control groups were well matched with respect to aortic clamp time, partial left heart bypass time, number of reattached intercostal arteries, and established risk factors for paraplegia. Two CSFD catheters occluded during operation and one CSFD catheter was dislodged during transport, but there were no complications directly attributed to the CSFD procedure.

This study by Coselli et al. provided Class I evidence (randomized, controlled trial with a positive outcome) supporting the efficacy of lumbar CSFD for prevention of paraplegia after TAAA repair. Strengths of this study include a standardized modern operative protocol to isolate the independent effects of lumbar CSFD, a large sample size of patients at high risk for postoperative paraplegia, and that it was performed at a center with the largest world-wide experience in the repair of TAAA. Weaknesses of the study may have been that it was performed only at a single center and that patients with extent III TAAA, who were also at risk for postoperative paraplegia, were not included. The study raised important new clinical questions. Is lumbar CSFD the new standard of care for the anesthetic management for TAAA repair? Is lumbar CSFD safe for patients subjected to full anticoagulation for partial left heart bypass with extracorporeal circulatory support? What is the optimal duration for lumbar CSF drainage and what is the optimal target lumbar CSF pressure to minimize the risk of paraplegia? Despite these uncertainties, and considering the morbidity associated with paraplegia, the evidence is mounting that lumbar CSF drainage works and should be considered an important therapy for the prevention or treatment of paraplegia in patients undergoing TAAA repair.

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