Colloid Cyst: Transcallosal Approach
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I would like to use this video to describe the indications for removal of colloid cyst via the transcallosal approach. This is a 56 year-old female who presented with headaches and progressive memory dysfunction. However, on MRI evaluation she did not demonstrate any significant ventriculomegaly. The cause of her symptoms can be potentially because of the mass effect of the colloid cyst on the forniceal bodies. Due to lack of significant ventriculomegaly, the transcallosal approach versus the endoscopic approach may be more reasonable. You can also see the location of mass within the roof of the third ventricle. A right-sided transcallosal approach was attempted. In this case, the patient was placed in the supine position and linear or a curvilinear incision can be used. Here's the location of the coronal suture. The incision is two third in front and one third behind the coronal suture. If the patient's head is placed in a neutral supine position anatomical orientation during the surgery, especially in the ventricle can be more accommodating. However, gravity retraction cannot be exploited for mobilization of the hemisphere. The latter is more possible if the head of the patient is in the lateral position. Neuronavigation was used to guide the trajectory of the operation. Small craniotomy was elevated on roofing the superior sagittal sinus. The dura was opened in curvilinear fashion. You can see the reflection of the hemisphere away from the midline. Untethering of the parasagittal vein is also demonstrated as suture was placed within the superior faux to mobilize the sinus away from the operative corridor. The inter hemispheric space was entered. Neuronavigation was used to guide our operative trajectory and minimize unnecessary dissection. The cingulate gyrus was sharply dissected and the pericallosal arteries were identified. You can see the glistening surface of the corpus callosum compared to the darker color of the cingulate gyrus. Obviously these two structures should not be mistaken for each other. Neuronavigation was reused to direct our operative trajectory in the exact location of the callosotomy. Additional dissection of the hemispheres, obvious the need for use of fixed retractors. Small carensotomy, almost a centimeter in length was used. You can see that the septum pellucid that is herniating into our operative corridor. If this problem arises, septum pellucidum should be finished striated in order to decompress the contralateral ventricle. Here's the fenestration of the septum. Now you can see that the pellucidum is no longer herniating into our operative corridor. You can see the right foramen of Monro, I used a piece of glove to slide around the brain and minimize the risk of injury to the brain from the friction at the surface of the carotenoids. Only small part of the cyst is often apparent. However, mobilization of the choroid plexus will further reveal the capsule of the cyst. Upon opening the capsule the cyst is readily decompressed, and now the capsule can be mobilized away from the choroid plexus and circumferential dissection of the capsule would allow its gross total removal. It is specially important that the capsule is disconnected exactly at the level of the choroid plexus so no residual capsule is left behind. Following complete removal of the cyst wall, which is almost disconnected completely here. The third ventricle will be inspected for any residual capsule wall. Here's the last attachment of the capsule to the anterior roof of the third ventricle. You can see that I have avoided fixed retractors. Here's the space within the third ventricle, no residual capsule wall is apparent. You can see the fenestration of the septum. The small extent of the callosotomy. MRD magnified view of the operative corridor without the use of fixed retractors. A ventricular catheter was placed in this case, since some bleeding within the ventricle was encountered during cyst removal. An immediate post-operative scan reveals gross total resection of the mass without any complication. Thank you.
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