Giant MCA Aneurysm: STA-MCA Bypass and Proximal M2 Occlusion
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Giant thrombotic or highly calcified aneurysms may not be safely a minimal to primary clip ligation. In these situations revascularization and proximal ligation or trapping can be quite effective for exclusion of the aneurism and preservation of the distal territories. This is a 62-year-old female who presented with acute speech difficulty and was diagnosed with a giant left sided partially thrombotic calcified MCA aneurysm. The aneurism is very large. It is mainly involving the temporal M2 trunk. It is not actually located at the MC bifurcation. Here's another view of this aneurysm which is somewhat fusiform obviously engulfing the entire M2 trunk. I felt the best methodology to tackle this aneurysm is to perform an STAMCA revascularization to one of the M4 or distal temporal branches followed by proximal occlusion of the M2 trunk. Let's go ahead and review the techniques for an STMCA revascularization procedure. The pathway of this STA was mapped using ultrasonography. This case the parietal branch was noted to be more desirable. Incision was fashioned to be able to expose the Sylvian fissure along this anterior limb for management and proximal occlusion of the M2. Here are the basic techniques for harvestation of the STA. A cuff of soft tissues left around the vessel to protect it. Some off the branches of the STA are obviously transected after adequately coagulated. Here's the frontal branch of the vessel that was disconnected. Here's the artery with this cuff of soft tissue. Muscle loops are used to mobilize the vessel. Here's the final length of the artery. Next, a left frontotemporal craniotomy was performed in the anterior Sylvian fissure was widely dissected after the bypass was completed. This STA can remain in continuity or be transected. However, heparin irrigation of the lumen is necessary to avoid its thrombosis if it is transected early at its distal ant. Here's the temporal lobe, frontal lobe. First part of the operation involves performance of the STMC bypass. A sizable quarter core branch on the temporal side is selected as the recipient vessel. This vessel is adequately skeletonized. You can see some spasm within the vessel due to its manipulation. The spasm is adequately relieved using papaverine soaked, gel fall. Here's the vessel after that spasm is relieved. Temporary clips are used to isolate a short segment of the vessel. An arteriotomy is completed. You can see the lumen of the vessel. Heparin irrigation is used periodically.. The distal end of the donor is cleaned out and fish mouthed as you can see here. The anastomosis is performed using 9-O sutures at the toe and the heel of the anastomosis. Next I use the 10-O suture to complete the two sides of anastomosis in an interrupted fashion. Here's two of the anastomosis. 10-O sutures are now being used to complete the rest of the anastomosis. Here's one of the last sutures for one of the two sides of anastomosis. I do believe the interrupted sutures are more effective than the running ones for STMC anastomosis since the running suture can potentially construct the anastomotic site. Here's the other side of the anastomosis. The needle is turned as it's being advanced through the walls to avoid any tear within the walls of the vessel. I do use burst suppression during the time where the MCA branches temporarily occluded. After the anastomosis is deemed complete temporary clips are removed. Some bleeding from that anastomotic site is expected and is a good sign that the site is patent. I use a piece of cotton to bolster and reinforce the side of the anastomosis. Doppler probe confirms patency of the donor vessel. Next, the MCA and more specifically the M2 branch just proximal to the aneurysm was exposed through the dissection of the Sylvian fissure. Again, the anterior portion of this Sylvian fissure. The sphenoid wing would be here. It's the large thrombotic partially calcified aneurysm and the M2 trunk directly leading into the aneurysm is confirmed and found. Temporary clip was placed across the temporal trunk joining the aneurysm and obviously proximal to the aneurysm. Intraoperative angiogram was performed to assure very small flow within the aneurysm and pittance of the bypass. A permanent clip replaced the temporary clip after intraoperative angiogram confirmed desirable findings. And postoperative angiogram demonstrates complete thrombosis and exclusion of the aneurysm and pittance of the STMC bypass graft. There is no evidence of postoperative ischemia. This aneurysm regressed in follow-up imaging and the patient made an excellent recovery from her operation. Thank you.
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