Sciatic nerve lesions occur only rarely in cardiac surgery patients. T
o evaluate potential causes for sciatic neuropathy, we reviewed the ca
rdiac surgery performed at one institution during the last 15 years an
d found only six instances of sciatic neuropathy. We examined medical
records for these six patients for potential etiologic factors and det
ermined that four of the six patients had undergone prolonged periods
of intra-aortic balloon pump therapy with a catheter placed through th
e femoral artery ipsilateral to the sciatic nerve lesion, and the othe
r two patients had an ipsilateral femoral artery occlusion. In additio
n, four of the six patients had severe symptomatic peripheral vascular
disease, and one of the other patients had severe and prolonged perio
perative hypoxia. Although all these patients had pure sciatic neuropa
thy clinically, two of the four patients studied with electromyography
had evidence of damage to the femoral nerve or quadriceps muscles ips
ilaterally. In addition to the neurogenic changes, there were electrom
yographic findings suggestive of muscle ischemia. These results indica
te that patients undergoing cardiac surgery may be at risk for develop
ment of a sciatic neuropathy if they have compromised blood flow throu
gh the femoral artery together with another cause for tissue hypoxia.
Furthermore, asymptomatic ischemia of the femoral nerve or quadriceps
muscles may occur in this clinical setting.