Influence on spinal cord blood flow and function by interruption of bilateral segmental arteries at up to three levels: experimental study in dogs.

STUDY DESIGN Segmental arteries were interrupted bilaterally at up to three levels to study the influence on spinal cord blood flow (SCBF) and function in dogs. OBJECTIVES Considering the need to limit blood loss during surgery for spinal tumors, such as total en bloc spondylectomy, we studied the SCBF and function after experimental interruption of segmental arteries at up to three levels. SUMMARY OF BACKGROUND DATA Interruption of bilateral segmental arteries at three consecutive levels (T11, T12, and T13) has reduced blood flow to the vertebral body of T12 by one fourth of the control flow, but effects on the spinal cord have not been determined. METHODS SCBF was measured in spinal cord gray matter at T12 using a hydrogen clearance method after ligation of bilateral segmental arteries at 1 to three levels (T11, T12, and T13) in 6 dogs. Spinal cord function was evaluated by spinal cord evoked potentials, motor-evoked potentials, and neurologic assessment in 6 dogs. RESULTS SCBF at T12 decreased to 92.4%, 87.8%, and 84.6% of control flow after ligation of bilateral segmental arteries at T12, T11 plus T12, and T11-T13, respectively. Spinal cord evoked potentials and motor-evoked potentials showed no significant changes in any dog after ligation at three levels. No neurologic degradation was observed in any dog. CONCLUSIONS Interruption of bilateral segmental arteries at three levels did not damage spinal cord function in dogs, suggesting that in patients, preoperative embolization at three levels to reduce blood loss during surgery for spinal tumors would not compromise spinal cord function.