Study design: Segmental arteries including the level of Adamkiewicz artery were interrupted bilaterally for up to 4 levels to study the effects on spinal cord blood flow and neurologic function in dogs.
Objective: To examine how many ligations of bilateral segmental arteries including the level of Adamkiewicz artery cause ischemic spinal cord dysfunction.
Summary of background data: Interruption of bilateral segmental arteries at >or=5 consecutive levels without the level of Adamkiewicz artery has been reported to risk producing ischemic spinal cord dysfunction in dog model. However, the effects of ligating including the level of Adamkiewicz artery have not been elucidated.
Methods: The 25 dogs in which Adamkiewicz artery originated from L5 level were taken in this study. There were 15 dogs divided into 5 groups: sham group, no ligation; group 1, ligation of bilateral segmental arteries at 1 level (L5); group 2, at 2 levels (L4-L5); group 3, at 3 levels (L4-L6); and group 4, at 4 levels (L3-L6). Spinal cord blood flow at the L5 spinal cord segment by laser-Doppler flowmetry, and spinal cord-evoked and compound muscle action potentials were measured simultaneously until 10 hours after ligation. Neurologic function was assessed using a modified Tarlov grading system 1 week after operation in 10 other dogs divided into 2 groups: 3 pairs group, ligation at 3 levels (L4-L6); 4 pairs group, at 4 levels (L3-L6).
Results: Spinal cord blood flow was 98.2%, 76.1%, 66.6%, 61.4%, and 53.5% in the sham group, groups 1, 2, 3, and 4, respectively, 10 hours after ligation. Abnormal spinal cord-evoked and compound muscle action potentials were observed in 1 out of 3 dogs in group 4. Postoperative neurologic evaluation identified all 5 dogs in 3 pairs group and 4 in 4 pairs group as having grade 5. There was 1 dog in 4 pairs group that had grade 4.
Conclusion: Interruption of bilateral segmental arteries at >or=4 consecutive levels including the level of Adamkiewicz artery risks producing ischemic spinal cord dysfunction.