In terms of all neurosurgical procedures, smoldering disease is a relatively risky procedure that may go relatively smoothly, but may also pose risks after surgery. Most commonly cerebral blood flow has developed a steady state of its own at the time of smoldering disease, and the surgery causes a disturbance in the blood flow and rewires the foreign blood flow, creating a more pronounced disturbance in the original blood flow, called cerebral hyperperfusion syndrome. The result is an already ischemic state in the skull, and the re-bypass leads to an increase in intracranial blood flow, which may lead to bleeding, or may increase later leading to stagnation and infarction of the original blood flow. Common complications such as the risk of bleeding and, more commonly, cerebral infarction, after the effect on the original blood flow, lead to redistribution of blood flow in the brain and the formation of surgical site infarction or primary site infarction. There is also the possibility that after bypass, blood flow may be clear during the surgery, but later in the surgery, small vessels may become occluded, resulting in a less than optimal outcome.