Brain Biopsy of a Suspected Cerebellar Lymphoma
So the case we are operating on is a 72-year-old lady who developed some severe gait ataxia. She has had an MRI which shows this contrast enhancing lesion which is adjacent to the fourth ventricle. And we suspect primary CNS lymphoma, so we opted for a biopsy, which - which will be in navigated frameless biopsy using the brainlab system. And our trajectory, you can see here - around 1 cm below the transverse sinus, so no need to injure that. And then we're going right into the contrast enhancing lesion, and our target will be at the level of the fourth ventricle so we don't hit the brainstem.
That's outside the 5mm target deviation. That's not good.
So now we've set up the biopsy device, and we have an estimated target deviation below 1 mm - so it's pretty accurate. And now we’ll confirm the trajectory using the needle. Good.
So the next step, we’ll do the skin incision and do the burr hole. So in this case, there’s some subcutaneous fat tissue and some of the neck muscles that we have to go through.
So now we’re drilling the bone. So in this case the dura has been perforated while drilling, which is not much of a problem, but it’s not the usual kind of procedure.
So now we have the surface of the cerebellum exposed. I'll coagulate where the needle goes into the tissue, using bipolar coagulation. So now, you see the needle in a trajectory. The - the pink - the pink square is the place where the biopsy is being taken. So now we insert the needle, you go forward, just a little. And now we're approaching the contrast enhancing tissue. You can see it in the upper right image. So we stop here, and then we took the first - take the first biopsy here.
So here we have our first specimen.
So now we're going a little bit deeper into - right into the lesion. Our philosophy is to biopsy the margin from normal tissue to the lesion and then do a biopsy within the lesion, and maybe we can have some macroscopic changes already, so we know that we are in the right place. So the second specimen looks a little different but...
Okay, so now, we are going a little deeper right into the lesion. Now we're right in the center. So here we don't have a sample. We’ll try to get one again. So here's the next sample, which looks a little - little different from the previous one. So we’ll take the last biopsy here, and then we - then we won't go any deeper, and on the way back, we’ll get some more specimens. Go out a little. Sample number 4. Now we go back a little more, and do two or three more biopsies, and then we're done. Sample number 6.
So this - this sample looks a little more translucent than normal brain tissue, so we can be quite sure that it's pathological tissue that we obtained.
Okay now we're going for the last biopsy. This looks more like normal tissue, so this tells us that the navigation is right, and we were most probably in the right spot.
Okay so the last step is to do some irrigation. If there was any bleeding, then the water drops would leak out of the needle, so if nothing happens, we can be quite sure there is no hemorrhage in the biopsy spot.
So this sample for example shows some fluorescence here, so we know we’re - we've been inside the contrast enhancing tissue. Let's take a look at one of the samples right from the center. So this is sample number 5, which is right from the center of the lesion, and it shows some fluorescence, so here we also know we're inside the contrast enhancing tissue.
As you have seen, we had an uneventful surgery - no signs for bleeding. The patient woke up very well, is going to the postanesthesialogical care unit for 2 hours, and then going back to the normal ward. As you've seen, we've experienced them some minor troubles because her shoulder was in the way of the camera for the navigation system. So we always had to push down the shoulders, so the camera was able to to detect all the navigation markers and the - the biopsy needle.