Sensitivity, specificity, and surgical impact of somatosensory evoked potentials in descending aorta surgery.
BACKGROUND
We evaluate the efficiency of multilevel somatosensory evoked potential (SEP) monitoring for intraoperative re-establishment of blood flow to the spinal cord in 63 patients undergoing descending aorta repair.


METHODS
The presence of critical vessels in a cross-clamped aortic segment was ascertained by a 15 minute SEP observation period while the segment between the clamps was vented to drain out the collateral flow.


RESULTS
SEPs influenced the surgical strategy in 17 cases (27%): use of the Biomedicus in 1 traumatic rupture; critical vessel reimplantation or distal clamp replacement in 13 cases of segmental spinal ischemia; and hastening the procedure or proximal clamp replacement in 3 cases of left carotid ischemia. There were no cases of unexplained multilevel SEP abnormalities. Immediate paraplegia was observed in 2 cases (1 pre-existing; 1 forecast by a 199-minute period of SEP absence due to segmental ischemia); 2 patients presented delayed paraplegias despite unchanged intraoperative SEPs, and 1 case presented a transient paraplegia due to lower motoneuronal involvement.


CONCLUSIONS
SEPs efficiently identified critical vessels to be reimplanted in order to avoid immediate paraplegia. However, systematic additional vessel reimplantation, if technically feasible, and prolongation of SEP monitoring during the postoperative period with careful blood pressure control are needed to prevent delayed paraplegia.
Guerit
J M
JM
Cliniques Universitaires Saint-Luc, U.C.L. Brussels, Belgium. guerit@nchm.ucl.ac.be
Witdoeckt
C
C
Verhelst
R
R
Matta
A J
AJ
Jacquet
L M
LM
Dion
R A
RA
D000328:Adult; D017545:Aortic Aneurysm, Thoracic / Q000601:surgery*; D003250:Constriction; D005073:Evoked Potentials, Somatosensory; D006801:Humans; D007511:Ischemia / Q000517:prevention & control*; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010264:Paraplegia / Q000517:prevention & control; D011183:Postoperative Complications / Q000517:prevention & control*; D012039:Regional Blood Flow; D012680:Sensitivity and Specificity; D013116:Spinal Cord / Q000098:blood supply*; D016896:Treatment Outcome