Measurement of lower limb blood flow in patients with neurogenic claudication using positron emission tomography

Ten subjects (seven with neurogenic claudication and three control subjects) underwent examination of lower limb muscle blood flow before and after exercise using positron emission tomography.

To investigate the hypothesis that lower limb muscle ischemia was the origin of symptoms in neurogenic claudication.

Patients with neurogenic claudication secondary to spinal stenosis experience lower limb discomfort after exercise similar to that of ischemic claudication. However, they do not have clinical evidence of peripheral vascular disease. The authors postulated that the lower limb discomfort in patients with neurogenic claudication may arise from muscle ischemia due to inadequate dilatation of arterioles in response to exercise, this itself arising secondary to sympathetic dysfunction due to spinal stenosis.

Using O15-labeled water and positron emission tomography measured thigh and leg muscle blood flow response to exercise bilaterally in seven patients with unilateral neurogenic claudication and three control subjects were measured.

The average values obtained for mid-thigh and mid-calf muscle perfusion at rest were 2.57 ml/min/100 g tissue (2.23-3.90) and 2.39 ml/min/100 g tissue (2.03-3.46), respectively. The average values obtained from mid-thigh and mid-calf perfusion after exercise were 4.41 ml/min/100 g tissue (2.8-6.0) and 4.87 ml/min/100 g (2.2-11.7). We found no difference in muscle perfusion between symptomatic and asymptomatic limbs in this group of patients.

These studies suggest that muscle ischemia is not the origin of symptoms in most patients with neurogenic claudication.