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Giant Pituitary Adenoma: Principles for Resection

August 13, 2016

Transcript

Let's review the technical principles for resection of giant pituitary adenomas, as well as nuances for maximizing resection. This is a 52 year-old male who presented with significant visual decline and mild confusion. MRI evaluation revealed a giant pituitary macroadenoma with significant hypothalamic and visual apparatus compression. Endonasal transanal resection was attempted. You can see the floor of a sellae is significantly expanded. The bone is relatively thin, readily removed via pituitary rongeurs. This was the initial exposure by one of my fellows. Exposure is reasonable, however, it's most likely inadequate. The dura was open in a cruciate fashion. The tumor extruded under pressure part of the tumor was removed. Ring currettes were utilized for further tumor debulking. Suction maybe utilized also to further remove the gelatinous tumor. You can see there is fair amount of tumor on the periphery of the sellae, that remains intact. Upon my arrival, I continue to further expand on the removal before additional tumor resection is attempted. Again, it's critical for maximal tumor resection of larger tumors that the bony exposure is very extensive and expands from one cavernous sinus to the other. The most common factor for subtotal resection of a pituitary macroadenoma is inadequate bony removal at the floor of the sellae. Significant amount of further bony removal was necessary. You can see the amount of dura that is now exposed upon additional bony resection. Here, you can see further bony removal anteriorly all the way to the level of tuberculum. Here's the margin of further dural exposure. Dural incisions were extended to the periphery of exposure and edges of the bony removal. You can see the amount of tumor that was hiding under the dural edges. So the first challenge is making sure bony removal is adequate and provides ample amount of space for resecting the tumor at the level of the periphery as you can see here. The limiting factor for allowing the middle of the tumor to descend is the residual tumor at the periphery of the tumor bulk. Now that the peripheral portion of the tumor can be resected, the middle of the tumor is much easier to handle. First, the posterior and the lateral portions of tumor are removed, and last, the more anterior and middle portion of the tumor are removed. The order of these steps is important so that the diaphragm does not descend prematurely and obstruct the view to the residual tumor along the lateral aspect of the resection cavity. Here again is my attempt to remove the tumor on the lateral aspect of the tumor bulk. As the lateral portions of the tumor are removed, the middle and anterior part of the tumor are also tackled and diaphragma sellae appears in view. Here's removal of the tumor within the middle of the resection cavity. This part of the tumor can be quite adherent to the diaphragma sellae. Here's diaphragma sellae. So the first challenge was adequate bony removal. The second challenge was making sure the portions of the tumor are removed in a specific order, and the third challenge is handling the very patulous and redundant diaphragma sellae without leading it to its injury. There's ample amount of tumor hiding within the faults of the redundant diaphragma sellae. These giant tumors to diaphragma is very much expanded and stretched and therefore is very patulous and one has to be able to handle these redundant faults so that the tumor that is hiding more superiorly and within the faults are adequately handled. Ample amount of irrigation is used to clear the operative field. Some of the tumor in this area has to be removed especially within the suprasellar cisterns. You can see the suction device is removing that portion of the tumor. I'm using the ring curette as a dynamic retractor to mobilize the diaphragm out of my way and be able to reach into the faults of the resection cavity Piece of carotenoid may be used to cover the diaphragma, therefore protecting the diaphragm from the suction device. As the diaphragm is mobilized, the suction device and its angled forms are used to remove the tumor within the hidden operative spots. Here's specially the portion of the tumor that is hiding within a very prominent diaphragmatic fault. Here is most likely the medial wall of the cavernous sinus. Here is, at the tip of the arrow, you can see that adequate bony removal allows careful examination and inspection of the medial cavernous sinus wall so the tumor removal is adequate. Inadequate removal and blind curetting often leads to subtotal tumor removal. Here's the medial cavernous wall on the left. I'm satisfied with the external resection laterally. You can see how the carotenoid is rolled around as I work within the faults of the diaphragm. Here's the more anterior aspect of the diaphragm as it attaches to the tuberculum. There is no necessary residual tumor. Furthermore, the posterior aspect of the resection cavity is inspected. No obvious residual tumor is apparent. Here is a more panoramic view of the intrasellar contents. The diaphragm is mobilized posteriorly. No obvious tumor is apparent. By the end of the resection usually the diaphragm is aggressively herniating through the sellae. Here is another sign that the dissection is complete. Here's using hydroscopy to inspect the diaphragmatic faults. No residual tumor is apparent within the diaphragmatic faults. This is a really nice maneuver to look within the faults and assure complete removal of the tumor mass. Very effective, atraumatic fashion to handle the diaphragm. The closure in this case involved a dural allograft inlay. Since the exposure was relatively extensive in this case, and a nasal slap or flap was available. The flap was also used to cover the skull-based defect. Here's the postoperative MRI, which revealed aggressive, gross total removal of the tumor. Again, the important points in this video, are number one, adequate bony removal. Number two, removal of the tumor in different portions of the tumor bulk in a specific order. In other words, first laterally, posteriorly, and ultimately, superiorly and anteriorly. The third important principle is handling the patulous diaphragm so that the diaphragmatic faults are adequately inspected for aggressive tumor removal. Thank you.

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