Blood Flow Unaffected by Spinal Stenosis
To study the acute effects of different degrees of spinal stenosis on neural-tissue blood flow and spinal-evoked potentials, 24 pigs were randomized into three groups of eight pigs: a control group with 0% stenosis, a 25% stenosis group, and a 50% stenosis group.
A 75% stenosis group was added when results of the randomized experiment had been analyzed.
Double-level spinal stenosis was introduced by placement of stenosing bands around the dural sac at L4 and L6. Neurologic function was monitored by sensory- and motor-evoked potentials. Regional blood flow (RBF) was measured in the stenotic segments between the bands and other regions of neural tissue by radioactive microspheres, before and after induction of stenosis.
Blood supply of the spinal cord and nerve roots in the segments between two central stenoses is preserved immediately after stenosis introduction by way of the segmental nerve pathway, even if nerve conduction is impaired.
Jespersen SM, Christensen K, et al. Spinal cord and nerve-root blood flow in acute double-level spinal stenosis. Spine
, Dec. 1997;22(24), pp2900-10.