Motor strokes sparing the leg: different lesions and causes

A considerable number of patients develop stroke without involvement of the lower limb. However, there are few reports about the motor syndrome when the leg is spared.

To study clinical findings, causative factors, and lesion topography in stroke patients with a motor deficit sparing the leg.

We studied 895 patients with paresis sparing the leg from the 3,901 patients enrolled in the Lausanne Stroke Registry. They were compared with 1,644 stroke patients with paresis involving the leg, by means of univariate and multivariate analysis.

Eight hundred forty-four infarcts (94.3%) and 51 hemorrhages (5.7%) led to weakness sparing the leg. Different sites of lesion were found, but the majority were caused by superficial infarcts. Almost half of the lesions were confined to superficial branches of the middle cerebral artery territory, with 276 (30.8%) in the anterior (superior) and 138 (15.4%) in the posterior (inferior) middle cerebral artery. More than half of the infarcts had a presumed embolic source from large-artery disease or from the heart. In comparison with patients with paresis involving the leg, patients without leg involvement had a lower prevalence of small-artery disease (P<.001), but a higher prevalence of migraine (P<.001), transient ischemic attack (P = .001), atherosclerosis without stenosis (P = .005), large-artery disease (P<.001), and left hemispheric strokes (P<.001). They also had a lower frequency of hemorrhagic stroke.

Patients without leg involvement had different stroke lesions and causes and were characterized by more superficial infarcts mainly caused by emboli from large-artery disease and atherosclerosis without stenosis.