Name:
Interhemispheric transcallosal intervenous approach to a pineal region tumor
Description:
Interhemispheric transcallosal intervenous approach to a pineal region tumor
Thumbnail URL:
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Duration:
T00H09M40S
Embed URL:
https://stream.cadmore.media/player/a7e19521-ff8a-4a8a-8e24-cfbcf7f4710c
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/a7e19521-ff8a-4a8a-8e24-cfbcf7f4710c/21-20.mp4?sv=2019-02-02&sr=c&sig=C0GbDmoITA9lj1kSC1NcYrMf%2FPLAEcuBzOzR%2F%2B1YOrg%3D&st=2024-05-04T05%3A00%3A45Z&se=2024-05-04T07%3A05%3A45Z&sp=r
Upload Date:
2021-10-27T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
SPEAKER 1: In this video, we present an interhemispheric transcallosal intervenous approach to a pineal region tumor. This is a case of a 15-year-old boy, with a history of headaches and double vision for a few weeks, without significant past medical history. Exam did highlight an abduction deficit in the right eye and bilateral papilledema. He's otherwise intact. The initial MRI showed up a pineal region tumor causing obstructive hydrocephalus.
SPEAKER 1: The tumor has significant deficient restriction and homogeneous contrast enhancement. There were no other lesions in the brain or the spine. Tumor markers AFP and HCG in blood were within normal limits. The main differential diagnosis in this situation remains germinoma versus pineal blastoma. At this m we decided to perform an endoscopic third ventriculostomy first to address the hydrocephalus, including an endoscopic biopsy with flexible endoscope through a single right frontal burr hole.
SPEAKER 1: The pathologic diagnosis came back as spinal blastoma. So in this context, tumor resection is indicated as a next step in the treatment, followed by craniospinal radiation and chemotherapy. Besides in patients older than five years old with focal disease, gross- total, near-total resection can improve overall survival and should be the goal. Among the options to approach this tumor, we always consider these three approaches for the pineal region, supracerebellar, occipital transtentorial, and the transcallosal intravenous approach.
SPEAKER 1: All these three options were considered valid and feasible for this tumor. However, we opted for the interhemispheric transcallosal and intravenous approach, as it provides a nice view of the plane of the tumor, anterior to the ICVs that is usually where the tumor is going to be attached, and where optimizing the view is always worth considering. Thus, this approach will allows us to have a nice view in front of the venous complex, preserving vermian vein, the central mesencephalic vein, and, of course, both Rosenthal veins.
SPEAKER 1: The patient is positioned in supine with the head turn rightwards, parallel to the floor. So the right hemisphere will fall down, opening the interhemispheric corridor naturally. Under the microscope, the right side is on the bottom of the screen. Thus, anterior is on the right upper corner of the screen. And posterior is left lower corner. The dissection of the interhemispheric fissure places us into the corpus callosum.
SPEAKER 1: Neural navigation is very helpful to drive the callosotomy exactly where we had to defined it preoperatively, right above this planium. This places has him to the left lateral ventricle, apparently. To confirm this, especially before the dissection of the velum interpositum in the midline, we expose also the right lateral ventricle, as we can see. Once we have both lateral ventricles exposed, we move forward with exposure of the tela choroidea in the roof of the third ventricle.
SPEAKER 1: Doing a midline dissection close to the splenium of the corpus callosum is always safe, as a body of the fornices should have already left in the midline and turned into the crus of the fornix in the anterior wall of the atrium. In the dissection of the velum interpositum we can identify all the layers of the tela choroidea. The opening of the upper sheath, exposed the vascular layer with a media posterior choroidal artery that, at this point, has already branches to the thalamus, and is basically supplying the choroid plexus.
SPEAKER 1: In this layer, we will also find both internal cerbral veins. We always take time to dissect the tela and arachnoid. As at the beginning, It may be hard to distinguish the arachnoid from the veins themselves. Once both ICVs come together in midline, is a good anatomical reference to know when the body of the fornix, leaves midline and turning into the crus.
SPEAKER 1: For bigger tumors, where a larger corridor maybe be desirable, opening the rest of the tela anteriorly and interforniceal fissure is also a good option. Finally, once we open the lower sheath of the tela, we expose the tumor. The tumor is broad, moderately vascular, alternating areas that are soft with others that are more fibrous, as expected.
SPEAKER 1: The initial debulking with suction is very efficient and allows us to expose anterior 2/3 of the third ventricle. Besides, we also notice a wide structure that is crossing midline, that should correspond to the superior commissure that surrounds the pineal region, the habenular commissure. The posterior commissure is seen at the bottom right over the tectal plate. This is a nice view that shows both commissures that we find around the pineal region, the superior commissure, habenular commissure, and the posterior commissure in the inferior margin of the pineal region on top of the tectal plate.
SPEAKER 1: The habenular commissure is hard to identify in the pineal region. And is most of the times, embedded into the tumor. But this tumor is relatively small, and has kept it and pushed it superiorly. As we move forward with the dissection and resection, following the tectal plate, we expose the aqueduct, having a nice view that confirms that the resection of the component of the tumor that was blocking it.
SPEAKER 1: Having done the dissection of the tectal plate and exposing the aqueduct, we cover it and protect it with a cottonoid for the rest of the case. We continue with the inspection and the dissection on both sides of the field, where the tumor is attached to the walls of the third. On the margins or periphery of the tumor, this turns more fibrous, as expected.
SPEAKER 1: The dissection, therefore, with suction is not as effective as it was with the soft component. But we can still get a nice, plane on both sides with patience and a gentle dissection. Finally, we leave the last piece to the end, since it was attached to the left internal cerebral vein, as it is seen on the preoperative MRI. We can see the big blue structure in the left side of the surgical field.
SPEAKER 1: In our experience, even small tumors like this one can be really attached to the walls of the vein. This section of the video demonstrates the added value of the interhemispheric atmospheric transcallosal approach for this particular tumor dissection. We're trying to dissect the tumor from the anterior and inferior side of the left intracerebral vein. This side will be hard to expose coming from the posterior approach, especially in the vertical trajectory of the vein, where the tumor is attached.
SPEAKER 1: We dissect the tumor as much as we can, until we lose the nice plane between the tumor and the vein. We insist to make sure there is no good plan that can be dissected. So we decide to trim or to shave the last piece. While constantly maintaining a nice view of the vein as our reference, we continue with coagulation of the tumor, trimming it with micro scissors until we reach the plane with a wall of the vein.
SPEAKER 1: In this part, we take time to make sure we have a good control of the last piece all around it before we cut it out, Taking advantage of the nice view that this approach provides for this particular case. And finally, we coagulate the implantation of the tumor. Thus we get a reasonable gross surgical resection of the tumor.
SPEAKER 1: We inspect the surgical field all around it. We see the right lateral wall with the right ICV, the left lateral wall with the left ICV, and the choroid plexus on the roof of the third ventricle, and finally, the final view of the surgical cavity with both ICVs. The postoperative MRI showed a complete resection of the tumor without complications.
SPEAKER 1: The patient recovered very well. He went home within five days after the surgery, without additional deficits, except for an expected Parinaud syndrome. The pathology confirmed a diagnosis of pineal blastoma. He completed treatment with craniospinal radiation, 23-Gy and 30-Gy boost in the surgical field followed by chemotherapy, with an autologus bone marrow transplant.
SPEAKER 1: Currently, his Parinaud syndrome has resolved. And there is no evidence of tumor recurrence.