Effect of segmental artery ligation on the blood supply of the thoracic spinal cord during anterior spinal surgery: A quantitative histomorphological fresh cadaver study

Abstract

Study Design. Human cadaver quantitative morphometric analysis of the blood vessels in the spinal cord after ligation of segmental arteries. Objectives. To investigate the effect of ligation of segmental arteries on the quantity and density of the blood vessels in the spinal cord. Summary of Background Data. Ligation of segmental arteries is often used in the anterior approach for correction scoliosis. However, whether or not segmental artery ligation is liable to deny the spinal cord an adequate blood supply, thus leading to paraplegia, still remains controversial. Methods. Eleven fresh cadavers were divided into control, unilateral, and bilateral groups. For the unilateral and bilateral groups, 5 segmental vertebral arteries (T7-T11) were ligated unilaterally and bilaterally, respectively. Then, the number and density of blood vessels at different levels in the 3 groups were measured. Results. Compared to that of the corresponding level in the control group, the number of blood vessels at T5 to L1 all decreased in the ligation groups. And significant differences were found at T8 (82.80 ± 16.36), T10 (77.80 ± 19.80), and T11 (99.20 ± 14.85) levels, compared to those of the corresponding levels in the control group: T8 (175.80 ± 8. 31), T9 (176.40 ± 32. 33), T10 (171.40 ± 9. 73), and T11 (189.20 ± 15. 92). Further decrease was found at each corresponding level in the bilateral group, and significant differences were found at T8 (65.80 ± 15.55), T9 (24.80 ± 13.43), T10 (0), T11 (0), and T12 (0) levels. Similar results were obtained with regard to the density of blood vessels. Significant differences were found at T11 (1.246 ± 0.112) and L1 (1.349 ± 0.109) in the unilateral group, and T9 (0.260 ± 0.088), T10 (0), T11 (0), T12 (0), and L1 (0.147 ± 0.117) in the bilateral group compared to those of the corresponding levels in the control group: T9 (1.810 ± 0.202), T10 (1.833 ± 0.175), T11 (2.308 ± 0.335), T12 (2.510 ± 0.617), and L1 (2.193 ± 0.033). Conclusions. This study suggests that the more levels the ligation encompasses, the higher the risk of spinal cord damage. Therefore, caution should be taken when several segmental arteries are to be ligated in the clinical setting. What is more, bilateral ligation, which is worse than unilateral ligation, can lead to a significant decrease in the number and density of blood vessels of the spinal. © 2005, Lippincott Williams & Wilkins, Inc.