Dissection and Removal of the Tumor

Lateral dissection is facilitated by the internal decompression and debulking of the tumor. In this phase, we can clearly identify the massa intermedia delimitating the most anterior part of the tumor, and we proceed with aspiration and fragmentation of the tumor using the surgical…the ultrasonic surgical aspirator that is an extremely effective tool to achieve this goal in the least invasive possible way because it fragments and aspirates progressively the tumor mass. You can see that the movements of the surgical aspirator are very, very small and very, very careful. Avoid to put the surgical aspirator too deep.

At the end of the internal decompression, we arrive in the depth to expose the inlet of the cerebral aqueduct. Here it is very clear the inlet of the cerebral aqueduct. We can identify the tectal plate and the tumor that is still adherent to the tectal plate that is widely opened with the posterior bulging from the tumor. We can clear the entrance of the sylvian aqueduct and identify more posterior remnants of the tumor that are adherent to the most internal part of the quadrigeminal plate.

After identification of the sylvian aqueduct, we continue our internal decompression of the tumor. We separate the inner core from the external pseudo capsule, and in order to limit as much as possible the risk of bleeding or lesion to the internal cerebral vein that at this part are located very close to the surgical field, as you can see in the right lower part immediately behind the self-retaining retractor. After dissection of other parts of the tumor, we apply again the surgical aspirator aspirating the blood, fragmenting the tumor tissue, and reducing progressively the tumor mass in the posterior half of the tumor. That is certainly the most difficult and complex part to remove completely because of the adhesions to the most posterior of the tela choroidea and of the possible tractions that you have to exert on the internal cerebral vein.

The technique of using the surgical aspirator is very clear. You can, again, see that the movement of the ultrasonic surgical aspirator are very slow, that the surgical aspirator does not penetrate into the tumor. It remains on the surface aspirating progressive layers of tumors. And without creating very deep areas of lack of tissue and just progressing slowly on larger surfaces in order to keep the light on the area where the surgical aspirator is applied and avoid excessive penetration of the instrument into the tumor mass. The left sucker can aspirate the tumor far from the normal brain, and the surgical aspirator can progressively fragment and aspirate the tumor tissue that has been carefully separated from the normal tissue, limiting as much as possible the risk of damage to normal tissue.

In this phase, of course, we are working in an area with a very significant and important venous afferents so we can have significant bleeding at this point and we have to manage them very carefully. But in this case, we were able to identify all major vessels, and we were able to remove the most important lateral remnants of the tumor quite easily because of the very nice light that we can bring even on the most lateral part of the third ventricle because of the wide opening of the choroid fissure. The importance of the complete and effective opening of the choroid fissure is very, very clear in these videos because it is very clear the control that we have of the most lateral part of the tumor that comes from the left thalamus and the control that we have on the most posterior part of the tumor that is always in good vision during the procedure and throughout the surgical steps.

The tumor is now almost completely devitalized and the bleeding is very much reduced if compared to the initial steps of the surgery. And the bleeding doesn’t come from the tumor anymore but may come from venous afferents that can be damaged during the surgical maneuvers of traction and dissection and that, of course, oblige us to remain very careful in the dissection and identification of the most posterior part of the tumor removal. We continue with progressive fragmentation and aspiration of the tumor mass that is still easy to identify in our microscope. You see that the bleeding, fortunately, at this point is relatively easy to control by simple aspiration and then the application of bipolar cautery is not very frequent. The small remnant can be identified and aspirated on the left thalamus with a good clearing of this area as well.

And at the end of the surgery, we can see nice clearing of the tumor of the left thalamus at the point of origin. Due to some bleeding, we prefer to leave in place the most posterior aspect of the tumor capsule, and we proceed with the identification of the small remnants that are close to the inlet of the cerebral aqueduct. Here we can see the most posterior part of the sylvian aqueduct and we can clearly identify some tumor remnants attached to the ependyma of the inner part of the quadrigeminal plate that is very much opened posteriorly by the presence of the tumor. You can see that our actions are very delicate and superficial.