title: Predicting the risk of paraplegia after thoracic and thoracoabdominal aneurysm repair.
abstract: BACKGROUND
  Endovascular repair of descending thoracic and thoracoabdominal aortic aneurysms is an appealing alternative to the standard surgical approach, but precludes revascularization of segmental arteries (SAs). For safer surgical and endovascular repairs, an accurate prediction of the risk of paraplegia in relation to the extent of SA sacrifice is needed.
  
  
  METHODS
  From January 1994 to October 2008, 609 patients (mean age, 63 ± 14 years) underwent surgical descending thoracic or thoracoabdominal aortic aneurysm repair without SA reimplantation. Three hundred seventy-six patients (62%) were male; 159 (26%) had urgent or emergent operation; 199 (33%) had previous aortic surgery. Somatosensory- or motor-evoked potential monitoring and cerebrospinal fluid drainage were routinely performed.
  
  
  RESULTS
  Hospital mortality was 10.7% (65 patients). Spinal cord injury (SCI) occurred in 3.4% (21 patients). The extent of resection-expressed as the number of SAs sacrificed (p = 0.007)-and the need for visceral artery reimplantation (p = 0.03) were independent risk factors for paraplegia. Further analysis identified four risk groups (p < 0.0001): fewer than 8 SAs sacrificed (group A, SCI = 1.2%); sacrifice of 8 to 12 SAs with proximal origin in the upper thorax (group B, SCI = 3.7%); 8 to 12 SAs sacrificed beginning in the lower thorax (group C, SCI = 15.4%); and 13 or more SAs sacrificed (group D, SCI = 12.5%). This four-group model more accurately predicts SCI risk than the Crawford classification (goodness of fit c statistic: 0.748 versus 0.640).
  
  
  CONCLUSIONS
  The extent of SA sacrifice is the most powerful predictor of paraplegia risk. For aneurysms of moderate extent, a more distal location involving the abdominal aorta increases the risk of spinal cord injury. Sacrifice of fewer than 8 SAs is associated with a very low paraplegia risk regardless of location.
authors.affiliation: Department of Cardiothoracic Surgery, Mount Sinai School of Medicine, New York, New York 10029, USA. stefanozoli@gmail.com.
authors.forename: Stefano
authors.initials: S
authors.lastname: Zoli
authors.forename: Fabian
authors.initials: F
authors.lastname: Roder
authors.forename: Christian D
authors.initials: CD
authors.lastname: Etz
authors.forename: Robert M
authors.initials: RM
authors.lastname: Brenner
authors.forename: Carol A
authors.initials: CA
authors.lastname: Bodian
authors.forename: Hung-Mo
authors.initials: HM
authors.lastname: Lin
authors.forename: Gabriele
authors.initials: G
authors.lastname: Di Luozzo
authors.forename: Randall B
authors.initials: RB
authors.lastname: Griepp
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017545:Aortic Aneurysm, Thoracic / Q000601:surgery*; D001158:Arteries / Q000601:surgery; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010264:Paraplegia / Q000209:etiology*; D012092:Replantation; D012189:Retrospective Studies; D012307:Risk Factors; D013118:Spinal Cord Diseases / Q000209:etiology*; D055815:Young Adult