As many of you may have read by now Senator Kennedy was awake at the time of his surgery to remove the malignant tumor from his brain. What does this mean? What is awake craniotomy (been awake during the time the cranium/ skull is open?)
I thought in this post I shall discuss awake craniotomy. As you know during most surgeries, patients are under deep general anaesthesia. We try to reach a plane of anaesthesia so that they feel no pain and also have no recollection of any events during the surgery. Sometimes though especially in brain surgeries we actually want them to be awake during at least a part of the surgery.
Why you may ask. Well take the case of Senator Kennedy, his tumor was in a location which is very near to eloquent areas of the brain (parts of the brain which control language/ memory/ movements of the opposite arm and leg that is his tumor was near the language and motor cortex). So in cases like these the surgeon wants you awake during a part of the procedure so that he can test that these functions are indeed intact. The patient is asked to speak, talk aloud or move the opposite arm or leg). This assures the surgeon that he is not near these vital areas of the brain and once he maps them out he can avoid them.
At times we do what is called cortical mapping. With the help of an electric probe, the surgeon touches parts of the brain near the region of interest (in this case a brain tumor), if when the probe is touched the patient has a language arrest or his hand or leg move, we know these are vitals parts of the brain. In this way we are able to map all the parts of the brain hence the name cortical mapping.
Awake craniotomy requires special type of anaesthesia and preparation. At times what is done is that the anaesthesia is turned off after the surgeon has cut open the skull and then the patient is woken up. Once the mapping has been carried out, the anaesthesia is restarted and the patient falls back asleep and then the surgeon continues with the surgery. Awake craniotomy is also carried out during deep brain stimulation (DBS) surgery for Parkinson’s disease.
I shall discuss DBS in a separate post.
Nitin Sethi, MD