An extended lumbar posture narrows a degenerative stenotic spinal canal to a critical threshold, leading to direct mechanical compression or indirect vascular compression of the nerve roots and/or cauda equina 4) 5).
The location of the symptoms (above the knees for neurogenic claudication; below the knees for vascular claudication) as well as the symptom alleviators (sitting for neurogenic claudication; standing for vascular claudication). However, alleviation of symptoms with standing alone has a moderate correlation with vascular claudication; its presence could direct physicians toward a vascular workup rather than neurogenic investigations.
Certain constellations of symptom attributes are more strongly associated with each type of claudication.
The presence of symptoms that are triggered with standing, relieved with sitting, located above the knees and have a positive shopping cart sign represent strong evidence that a patient has intermittent neurogenic claudication rather than vascular claudication. On the other hand, a patient with symptoms that are relieved with standing alone and located below the knees is much more likely to have vascular than neurogenic claudication 6).