Operative results of thoracoabdominal repair for chronic type B aortic dissection

From January 1991 to May 1994, we have operated on 15 cases of Type B aortic dissection. In 10 of these patients, thoracoabdominal repair was performed. According to Crawford's classification, 2 patients fell into Type I, 6 patients into Type II, and 2 patients into Type III. The aneurysms were exposed through a left thoracotomy extending into the retroperitoneum with the hemidiaphragm divided circumferentially. The operations were performed under femoro-femoral partial cardiopulmonary bypass. In 6 of these cases selective perfusion of the visceral branches was used. The celiac axis was reconstructed in 10 patients, superior mesenteric artery in 9, right renal artery in 7, left renal artery in 6. Abdominal vessels were reconstructed by the "inclusion" technique described by Crawford in 2 patients, by "beveling" the distal prosthetic end in 6 and by the "interposition" technique in 4 patients. Vessels arising from the false lumen were reconstructed by the "interposition" technique. To prevent paraplegia, the evoked spinal cord potentials by direct stimulation of the cord (ESPs-dsc) were monitored perioperatively and the aneurysms were repaired sequentially in segments. In all patients except 2 with Crawford type III aneurysms, spinal cord ischemia was detected by ESPs-dsc. In 7 of these patients, 2 to 8 pairs of intercostal/lumbar arteries (I/L aa.) that arose from the "responsible" aortic segment were reconstructed. Reconstruction techniques included the "inclusion" technique in 2 patients, the "beveling" technique in 1, the "interposition" technique in 1 and the "on lay grafting" technique in 3 patients. One hospital death occurred in a patient who had chronic renal insufficiency and liver cirrhosis preoperatively. Spinal cord injury occurred in 5 patients, including 4 paraparesis and 1 delayed-onset paraplegia. In 2 of these patients, responsible I/L aa., were not reconstructed correctly despite ESPs changes, and injury might have been prevented if reconstruction of the "responsible" arteries had been performed. Thoracoabdominal repair for chronic Type B aortic dissection could be performed safely with an acceptable mortality rate. Spinal cord injury remains an unsolved problem.