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Craniopharyngioma: Pterional Approach

March 25, 2016

Transcript

Let's review the transcranial methodology for resection of suprasellar craniopharyngiomas. This is using the terminal approach. This is a 41 year-old male who presented with progressive history of visual dysfunction. MRI evaluation revealed a super cellar mass, partially cystic with multiple nodules causing significant involvement of the optic apparatus. Nodule is located slightly toward the left side and therefore a left sided perianal craniotomy was attempted. Let's go ahead and review the details of the exposure. The roof of the orbit was reduced using drilling so that the subfrontal approach is unobstructed by the inferior edge of the craniotomy. The lateral aspect of this sphenoid wing and the area of the tarion was also resected. Here's removal of the lateral sphenoid wing. Here's the drilling over the roof of the orbit, all the gyrations and protuberances in this area are drilled flat. So they will not interfere with our subfrontal trajectory toward the perichiasmatic area. I can see the final result. Most of those gyrations are drilled flat. Gel foam soaked with thrombin is used to achieve hemostasis. I minimize placing too much bone wax in this area that can also interfere with the subfrontal trajectory. The dura is open in a curvilinear fashion. You see, most of the exposure is frontal, very small amount of the temporal area is exposed. Here's the Sylvian fissure. Brain appears relatively relaxed. Elevation of the frontal lobe can expose the tumor cyst as well as the optical carotid sisters for early drainage of CSF, providing additional route for brain relaxation. The cyst of the tumor was also fenestrated within the inter optic space. The lateral convexity of the brain was covered with a piece of telfer to protect against thermal injury from the intense light of the microscope. Sylvian fissure was dissected using standard techniques described in other videos within the Atlas. A round knife was used to open the distal more superficial thick arachnoid band of the Sylvian fissure. Driller forceps were next used to carefully dissect the thick superficial arachnoid bands. This method is quite efficient, protects the thin walled veins. Next micro scissors are used to open the Sylvian fissure from inside to outside technique again, I stay deep within the fissure more distally and then dissect from deep to superficial to be able to atraumatically separate the inter digitating frontal and temporal opercular. In the inside to outside technique you can see, I start deep and go superficial. Here is the spreading action of the forceps working from deep to superficial, Then micro scissors complete the job. Next I work along the posterior subfrontal area to further remove the tumor capsule around the ipsilateral optic nerve so that the nodule can be exposed. Working within the retro carotid space to drain the septations within the cyst. Here's the carotid artery. The cyst capsule is also removed when deemed safe. Here's working within the inter-optic space. Dissecting the capsule, the tumor from subfrontal area. I can see there is a separation or dissection plane between the capsule of the tumor and the arachnoid bands. Dynamic retraction is used. Now I divert my attention toward the nodule of the tumor that is adherent to the area of the hypothalamus, The pool of the cyst wall. Again, affecting the contralateral optic nerve is removed. Next a pituitary stock has to be identified and the tumor adherent to the stock has to be dissected. Here is the nodule of the tumor adherent to the area of the hypothalamus. I inspected the section planes and visibility of course, to remove all the nodule without injury to the area of the hypothalamus. All the perforating vessels are obviously protected. It's contralateral carotid artery and optic nerve. Some of the perforating vessels, reasonable operative trajectory without the use of fixed retractors. Here's the pituitary stock using sharp dissection, the tumor is being mobilized away from the stock while preserving the stock. Working posterior to this stock to inspect any evidence of residual tumor. was also dissected and some of the capsule of the cyst is being dissected. And using sharp dissection for removal of the capsule from the posterior aspect of the optic nerve. One has to look through a very steep inferior to superior operative trajectory to dissect the nodule from the area of the hypothalamus. Again, I continue right now to dissect the tumor capsule. This contralateral third nerve, dissection of the capsule away from this nerve. Again, inspecting the retro carotid space, working on both sides of the carotid artery, I had to level the skull base to maximize resection of the cyst wall. Obviously gross to remove the wall, is not possible. However, I tend to remove as much of the wall as possible safely. Here's the nodule, at least part of it that has been dissected from hypothalamus. Here's another piece of the nodule that has been dissected from the hypothalamus small piece of the tumor capsule is left behind over the hypothalamus to avoid hypothalamic injury. Here, you can see the hypothalamus, the nodule of the tumor. Very adherent in this area. Continue to dissect the tumor Further inspection reveals no gross residual tumor mass. All the perforating vessels are protected. Posterior arachnoid third nerve, nice anatomy of the skull-based ipsilateral optic nerve. Carotid artery and olecranoid process, beautiful anatomy of the periachiasmatic area, intact pituitary stock. Looking through tore the interpeduncular cistern. As our artery S-C-A-N-P-C-A-R also demonstrated small piece of the capsule that was left adherent to the hypothalamus. You can see minimal amount of injury to the brain in the absence of fix retractor blades. The dura was closed. Post-operative MRI revealed gross total removal of the mass, preservation of the pituitary stock, no evidence of residual tumor on the coronal image. However, small perforator stroke unfortunately occurred. This could be because of vasospasm related to manipulation of the tumor capsule. However luckily this patient did not suffer from any sequelae related to this infarct and made an excellent recovery with resolution of his preoperative visual deficits. Thank you.

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