Transchoroidal Approach to Tumors of the Posterior Third Ventricle

Internal Debulking of the Tumor

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In this segment, we perform the longest part of the procedure, voiding of the central part of the tumor in order to allow the dissection of the lateral aspects from the third ventricle walls.

Keywords

  • Internal decompression
  • Ultrasonic surgical aspirator
  • Aspiration
  • Fragmentation
  • Floor of the third ventricle
  • Massa Intermedia
  • Adhesio interthalamica

About this video

Author(s)
Giuseppe Cinalli
Nicola Onorini
First online
07 February 2019
DOI
https://doi.org/10.1007/978-3-030-13673-4_6
Online ISBN
978-3-030-13673-4
Publisher
Springer, Cham
Copyright information
© The Author(s) 2019

Video Transcript

After biopsy of the tumor, we proceed to internal debulking of the tumor mass. We use the ultrasonic surgical aspirator set at 40 or 50 percent of the power both for the power and the aspiration strength. We are facilitated by the presence of a large internal cavity created by the necrotic core of the tumor mass. We work with the ultrasonic aspirator with very slow movements in order to limit the application of it to the superficial parts of the tumor and avoid the deepening of the instrument inside the surgical cavity.

After an initial debulking, we can create a dissection plane between the tumor and the lateral walls of the third ventricle. This maneuver can be a little bit limited by the bleeding of the small vessels that are depending on the vascularization starting from the tela choroidea, but usually, this bleeding can be easy to limit and to control.

We proceed anteriorly in order to identify the anterior pole of the tumor. We can see the massa intermedia that is hiding the most anterior part of the tumor, but massa intermedia can be easily pushed anteriorly in order to gain vision and to gain a larger view of the most anterior part of the third ventricle. We proceed to shrinking also of the mass with coagulation, but as you can see, the dissection is very slow and very careful in order to avoid excessive tractions on the mass.

We identify the anterior pole of the tumor, identifying the next steps, the ependyma of the third ventricle. In this phase, the tumor mass is still creating an obstacle to the identification of the more anterior third ventricle so we proceed to shrinking of the capsule and the devascularization of the outer part of the tumor in order to facilitate this maneuver of identification of the anterior pole of the tumor merging into the third ventricle. We coagulate progressively.

And as you can see, at the end of this procedure, we can finally identify the ependyma of the third ventricle that gives to us the certitude that we have found and identified the anterior pole of the tumor. And we can set this anterior limit by putting a small cotonoid into the third ventricle. And we can proceed with the step of the internal debulking that is certainly the most tedious and longest phase of the tumor because the mass of the tumor is not negligible.

The tumor, fortunately, is hemorrhagic but not very much, and it allows the use of a surgical aspirator coupled with a sucker in order to maintain a clear view of the structure that are aspirated into the surgical aspirator. It is very important in my practice not to go too deep into the tumor with the surgical aspirator in order to avoid, or at least limit as much as possible, the risk of injury of deeper structures. This technique of keeping the surgical aspirator steady at a certain distance from the tumor creates an attraction of the tumor toward the sucker created both by the sucker that is used with the left hand and by the sucker of the surgical aspirator and keeping the instrument far from structures that can be damaged by an excessive penetration of the instrument inside the tumor tissue.

This part, as you can see, is slow. It’s boring. It is, of course, extremely careful and necessitates frequent adjustment of the self-retaining retractors to achieve vision of the most lateral part of the tumor.