F wave studies of neurogenic intermittent claudication in lumbar spinal stenosis

Am J Phys Med Rehabil. 2006 Feb;85(2):135-40. doi: 10.1097/01.phm.0000197586.91860.a1.


Objective: Lumbar spinal stenosis (LSS) may result in neurogenic claudication (NC), which is thought to be a result of transient ischemia during exercise. In this study we evaluated the changes in F wave studies before and immediately after walking stress in patients with NC.

Design: Twenty-six patients with LSS who had signs and symptoms of NC and 20 healthy volunteers were included in this study. Routine motor and sensory nerve conduction studies and tibial F wave studies were performed in both groups. Immediately after walking stress test, tibial F wave studies were repeated. Exercise treadmill protocol was used for ambulation. Time to first symptoms and total ambulation time were recorded.

Results: After completion of the baseline electrophysiological examination, a walking stress test was performed using a treadmill, and 16 patients (61.5%) experienced neurogenic claudication during the trial. The mean time to first symptoms was 2.0 +/- 3.5 mins (minimum = 0, maximum = 14). In the control group 18 subjects (90%) completed the trial without any symptoms, and 2 (10%) subjects had to stop at an average of 10 mins because of generalized fatigue. Within 5 mins after the walking stress test, tibial F wave studies were repeated in both groups. There were significant increases in F latency values bilaterally in the patient group (P = 0.001 for both sides) but not in control subjects (P = 0.435 for right side and P = 0.122 for left side).

Conclusion: Our data suggest that F wave studies after walking stress test provide more information for the diagnosis of NC.

MeSH terms

  • Case-Control Studies
  • Electromyography
  • Exercise Test
  • Female
  • Humans
  • Intermittent Claudication / diagnosis
  • Intermittent Claudication / physiopathology*
  • Lumbar Vertebrae / physiopathology*
  • Male
  • Middle Aged
  • Neural Conduction / physiology*
  • Pain Measurement
  • Spinal Stenosis / physiopathology*
  • Tibial Nerve / physiopathology*