Assessment of spinal cord integrity during thoracoabdominal aortic aneurysm repair.
BACKGROUND
Monitoring motor-evoked potentials (MEPs) is an accurate technique to assess spinal cord integrity during thoracoabdominal aortic aneurysm (TAAA) repair, guiding surgical strategies to prevent paraplegia.


METHODS
In 210 consecutive patients with type I (n = 75), type II (n = 103), and type III (n = 32) TAAA surgical repair was performed using left heart bypass, cerebrospinal fluid drainage, and MEPs monitoring.


RESULTS
Reliable MEPs were registered in all patients. The median total number of patent intercostal and lumbar arteries was five. After proximal aortic crossclamping, MEP decreased below 25% of base line in 72 patients (34%) indicating critical spinal cord ischemia, which could be corrected by increasing distal aortic pressure. By using sequential clamping it appeared that in 43% of type I and II cases spinal cord circulation was supplied between T5 and L1, and 57% between L1 and L5. In type II and III cases cord perfusion was dependent upon lower lumbar arteries in 16% and pelvic circulation in 8%, necessitating reattachment of these segmental arteries. In 9% of patients critical ischemic MEP changes occurred without visible arteries, requiring aortic endarterectomy and selective grafting. One patient suffered early paraplegia and 2 delayed, and 2 patients had temporary neurologic deficit (5 of 210; 2.4%).


CONCLUSIONS
In patients with TAAA, blood supply to the spinal cord depends upon a highly variable collateral system. Monitoring MEPs is an accurate technique for detecting cord ischemia, guiding surgical tactics to reduce neurologic deficit (2.4%).
Jacobs
Michael J
MJ
Department of Surgery, University Hospital of Maastricht, The Netherlands. m.jacobs@surgery.azm.nl
Elenbaas
Ted W
TW
Schurink
Geert W H
GW
Mess
Werner H
WH
Mochtar
Bas
B
D000328:Adult; D000368:Aged; D000784:Aortic Dissection / Q000401:mortality / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality / Q000601:surgery*; D017545:Aortic Aneurysm, Thoracic / Q000401:mortality / Q000601:surgery*; D003097:Collateral Circulation / Q000502:physiology; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007431:Intraoperative Complications / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009460:Neurologic Examination; D011379:Prognosis; D015203:Reproducibility of Results; D020760:Spinal Cord Ischemia / Q000503:physiopathology / Q000517:prevention & control*