CASE 3—2005 Risk and Benefits of Cerebrospinal Fluid Drainage During Thoracoabdominal Aortic Aneurysm Surgery

Repair of descending thoracic and thoracoabdominal aortic aneurysms (TAAAs) is associated with a substantial risk of perioperative spinal cord ischemia that may or may not lead to permanent postoperative paralysis. Several techniques that aim to increase the ischemia tolerance time of the spinal cord during the period of aortic cross-clamping have been described in the literature.1 Hypothermia, left heart bypass, various shunts, myriad drugs, and cerebrospinal fluid (CSF) drainage have all been used alone or in combination to potentially improve neurologic outcome after surgery. CSF drainage and distal aortic perfusion have been shown to lower the incidence of neurologic complications after repair of type I and type II TAAAs. 2 Distal aortic perfusion increases distal aortic pressure, and CSF drainage decreases CSF pressure. These techniques potentially lead to an augmentation of spinal cord perfusion pressure during the period of aortic cross-clamping. However, CSF drainage can be associated with potentially serious complications, including fracture of the catheter during removal, catheter-associated meningitis, and/or temporary abducens nerve palsy, among others. 3 Also, epidural hematoma at the catheter insertion site can complicate the clinical assessment of postoperative spinal ischemic injury. 4 Intracranial subdural hematomas, with excessive CSF drainage, have also been reported and are associated with significant morbidity and mortality. 5 Subsequently, some authors have challenged the efficacy of CSF drainage and question the acceptable risk: benefit ratio of the technique. 6,7