Cerebrospinal Fluid Drainage Safe in Thoracic Aortic Repairs Using Extracorporeal Circulation

Cerebrospinal fluid (CSF) drainage during thoracic aortic surgery is not associated with a higher incidence of permanent paraplegia or haemorrhagic complications, according to a study presented here on February 2nd at the 39th Annual Meeting of the Society of Thoracic Surgeons.

All patients received extracorporeal circulation using full heparinisation, said lead investigator Albert T. Cheung, MD, of the University of Pennsylvania, in Philadelphia, United States, who evaluated procedures performed between 1993 and 2002.

Surgeons performed thoracic aortic repair in 143 patients with a mean age of 67 years. Surgeons inserted CSF catheters at L3-5 and drained the CSF to maintain pressures of 10-12 mm Hg. For patients without neurological deficit or coagulopathy, the catheters were capped at 24 hours and removed at 48 hours. In patients with delayed onset paraparesis, CSF was drained 24 hours after insertion to reverse the deficit.

The team used CSF drains in 122 thoracoabdominal aortic aneurysms (59 were Crawford type I; 25 were type II; 29 were type III; 9 were type IV) and in 21 descending thoracic aortic repairs (18 aneurysms; 2 traumatic aortic injuries; 1 aortic coarctation). Left atrial-femoral bypass was used in 113 patients, and full cardiopulmonary bypass in 30, with 22 of these requiring hypothermic circulatory arrest.

Time between catheter insertion and anticoagulation averaged 188 minutes. Heparin achieved a maximum activated clotting time of 542 seconds. Mean extracorporeal circulation time was 109 minutes and mean hypothermic circulatory arrest time was 39.4 minutes.

Nine percent of the 143 patients died and 6.3% developed permanent paraplegia. None of the patients developed epidural or spinal haematoma. Catheter-related complications, seen in 3.5% of patients, included temporary abducent nerve palsy in 1 patient; retained catheter fragments in 3 (1 case of meningitis); and 1 case of meningitis with persistent CSF leak. All patients recovered fully without sequelae.

Dr. Cheung noted, however, that the catheter fractured on removal in some patients. He said this appeared to be related to the elasticity of the catheter. The incidence of catheter fracture was reduced when the surgeon who inserted the catheter also removed it, he added.