Callosotomy

After adequate exposure of the corpus callosum, we proceed to the callosotomy on the midline deviated on the right side. Corpus callosum can be quite thick, but normally, in case of chronic hydrocephalus, it is thinner than one centimeter, like in this case. We immediately find the ependyma of the lateral ventricle. We proceed to further and careful coagulation of the ependyma in order to coagulate the ependymal vein and avoid remote bleeding during surgery. We realize after callosotomy that we have entered into the left lateral ventricle because we can see the septum pellucidum bulging into the surgical field that identifies the left lateral ventricle.

We proceed deeper with the self-retaining retractors into the lateral ventricle in order to expose the choroid plexus and the left foramen of Monro confirming our presence into the left lateral ventricle. And due to the anatomy and to the distortion of the left foramen of Monro, we prefer to change our strategy and to cross the septum pellucidum and enter into the contra lateral ventricle to obtain better vision of the right foramen of Monro and to start the dissection of the choroidal fissure from the right foramen of Monro.

The septum pellucidum is, again, exposed during surgery. It is coagulated above the septal vein and gently open and gently dissected in order to obtain an opening of the septum itself that is sufficient to expose the choroid plexus of the right lateral ventricle and the foramen of Monro of the right lateral ventricle. The dissection and the coagulation must be careful in order to avoid injury to the contra lateral structures. And after careful identification of the ependyma of the right thalamus and of the choroid plexus of the right ventricle, we proceed to enlargement of the septostomy, coagulation of septal veins that could bleed during the further surgical steps, and section of the septal veins that have been coagulated during the septostomy in order to obtain septostomy that is large enough, exposing correctly the right ventricle, the right choroid plexus, the right foramen of Monro, and the choroidal fissure.