This is important in decompression procedures for both disc herniation and for spinal stenosis (narrowing of the spinal canal or nerve root opening). Removing disc material pressing on the nerve root is the goal of nerve root decompression. Restoring blood flow to the area at the same time helps with the healing process.
In the case of spinal stenosis, interruption of blood supply is the major problem. In both cases, restoring free arterial blood flow is a good endpoint for decompression.