[Subdural haemorrhage following lumbar spinal drainage during repair of thoraco-abdominal aneurysm].

Physicians in charge of patients undergoing thoracic or thoraco-abdominal aneurysmectomy, frequently use lumbar spinal drainage of the cerebrospinal fluid (CSF) to prevent paraplegia. Whereas the profit of this technique is a much debated question, we report 2 case reports of delayed sub-dural hemorrhage, after lumbar spinal drainage of CSF. Cross clamping of the aorta decreases the spinal cord artery pressure, increases the cerebral pressure and by alterations of distribution of the venous return, is responsible for an increase of the CSF pressure. This increase of the CSF pressure decreases the spinal cord driving pressure. Lumbar spinal drainage of CSF aims to improve the spinal cord driving pressure close to the normal (where driving pressure = aortic pressure - CSF pressure). The two case reports have to be added to the liability of a method of prevention that, as attractive that it is, did not give the proof of its efficiency to decrease the frequency and/or the severity of paraplegia after thoracic or thoraco-abdominal aneurysmectomy. At this time, this technique should be reserved to the patients with documented risk, as it is possible using preoperative spinal cord arteriography. The insertion and the withdrawal of the catheter must be done in the usual conditions of medullar puncture with regard to anticoagulant and antiplatelet agents