Sometimes, it may be necessary to block off a blood vessel as the primary means of treating a problem. If that blood vessel supplies the brain, doing so might result in a stroke. However, at the base of the brain, there can be connecting vessels which can take over the blood supply. Because we are not certain, in some patients, that these connections are sufficient, we do a test beforehand. This testing involves temporarily blocking off the blood flow in the vessel we are interested in permanently blocking.
We do this with a small, soft balloon placed in the artery. With the balloon in place and inflated, we can then perform a neurological examination on the patient to make sure there is no problem. If the blood flow is insufficient, the patient will start to develop neurological impairment, such as weakness, loss of sensation, speech problems, etc.
When this happens, the balloon is deflated to restore the normal blood flow. Depending upon these results, we can then decide on the most appropriate course of therapy.