Importance of extrasegmental vessels for spinal cord blood supply in a chronic porcine model.
OBJECTIVE
Our purpose was to investigate the interaction of the important components of spinal cord blood supply in the pig model to enable its use for future studies of spinal cord protection.


METHODS
Twenty-five juvenile pigs (20-22 kg) underwent serial intercostal (IC) or lumbar artery (LA) ligation until disappearance of motor evoked potentials (MEPs). Pigs underwent sequential craniocaudal IC/LA ligation alone (n=5); following clamping of both subclavian arteries (n=4), or clamping of the median sacral artery (MSA, n=4). Animals also underwent serial caudocranial clamping of LA/IC alone (n=4); preceded by clamping of the subclavian arteries (n=4), or of the MSA (n=4). Results were verified by Tarlov's scores and perioperative angiography.


RESULTS
All animals with MEP loss suffered postoperative paraplegia. Groups were equivalent with regard to stable arterial pressures (64.6+/-3.1 degrees C) throughout the experiment, temperature (36+/-1.1 degrees C) and other physiological parameters. Mean number of clamped IC/LA before MEP loss for cranio-caudal clamping direction was 12.8+/-0.8 for segmental arteries isolated, 9+/-0.8 if both subclavian arteries were ligated previously and only 4.3+/-0.5 IC if the median sacral artery was clamped before. Mean number of clamped LA for caudo-cranial clamping direction was 5.8+/-0.9 for segmental lumbar arteries, 5.5+/-0.6 LA if both subclavian arteries were ligated previously and 3.5+/-0.6 if the median sacral artery was clamped before.


CONCLUSIONS
This study confirms the importance of lumbar and MSA arteries to cord viability. It documents the interaction of the subclavian and MSA (roughly equivalent to the hypogastric arteries in humans) with segmental vessels in providing spinal cord blood supply. It also provides the physiologic basis for use of the pig model for studies of spinal cord protection in aortic surgery.
Department of Cardiothoracic Surgery, Mount Sinai School of Medicine/New York University, New York, NY 10029, USA. ju.strauch@gmx.de
Justus T
JT
Strauch
David
D
Spielvogel
Alexander
A
Lauten
Ning
N
Zhang
Howard
H
Shiang
Donald
D
Weisz
Carol A
CA
Bodian
Randall B
RB
Griepp
D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D017545:Aortic Aneurysm, Thoracic / Q000601:surgery*; D001794:Blood Pressure; D002908:Chronic Disease; D004195:Disease Models, Animal; D019054:Evoked Potentials, Motor; D016343:Monitoring, Intraoperative / Q000379:methods; D010100:Oxygen / Q000097:blood; D010264:Paraplegia / Q000209:etiology / Q000517:prevention & control; D012039:Regional Blood Flow; D013116:Spinal Cord / Q000098:blood supply*; D020760:Spinal Cord Ischemia / Q000209:etiology / Q000517:prevention & control*; D013552:Swine
D010100:Oxygen