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STA-MCA Bypass for Carotid Occlusion

December 11, 2014


This video reviews the principles of superficial temporal artery to middle cerebral artery revascularization technique for symptomatic carotid artery occlusion. This is a 56 year old female, who presented with persistent left-sided hemispheric hypoperfusion syndrome. You can see the spec studies and the caliber of the STA branches. Patient underwent the relatively linear incision of the left temporal area. The superficial temporal artery was carefully dissected subcutaneously. Let's go ahead and review some of the basic principles here. The distal end of the STA branch, within the incision has been identified. Switchers are used to mobilize the scalp laterally and posteriorly. I use the spreading action of the scissors to dissect the scalp layers. The soft tissues are carefully dissected. The branches of the STA are carefully protected. You can see the Clamps here I used to gently elevate the scalp flap after the flap is dissected from the STA. And then I use the knife just over there. Mosquito or a Kelly clamps to further extend the incision of the scalp more inferiorally. Here's the STA. And you can see the Kelly clamps or the mosquito clamps are used to spread and dissect the sculpture superior to the STA. Next, the clamps elevate the skull flap while the knife is used to further extend the incision. This maneuver is quite efficient and safe in exposing the STA. We're now reaching just close to the root of the zygoma. Small branches of the STA are isolated, coagulated and cut. This should not be avulsed to protect the lumen of the STA. The STA is not yet disconnected more distally. Here's a temporal branch of the STA that is circumferentially dissected. It is next, And I get it using fine sutures and then disconnect it. All these measures, again, enhance the safety and the health of the STA, as a donor vessel. The STA is gently elevated and obviously disconnected along it's inferior aspect. Pieces of papaverine in soft gelfoam are used to bathe the STA during the entire process. The root of the STA is especially well mobilized In this case the cotton is soaked in papaverine where we use to cover the STA. I use a piece of glove to wrap the STA and mobilize it out of the working zone of the surgeon, during performance of the craniotomy. You can see a cut piece of glove, Which will wrap around the STA, along most of its length. And two sutures are placed along the ends of this wrap, so that the STA is adequately covered and mobilized out of the working zone, during performance of the craniotomy. Additional sutures may be placed to completely enclose the STA with the plastic wrap. Again, papaverine irrigation is used. The incision may be extended more posteriorly if necessary for further exposure and a larger craniotomy especially if the preoperative CTA demonstrates presence of a nice recipient vessel, more posterior to the route of the STA. I usually cut the temporalis muscle in a cruciate fashion. Disconnect the temporalis muscle from the superior temporal line. Again, you can see the STA mobilized out of our working zone and out of harm's way during drilling. A suction device may be placed permanently into the operative space to keep the area clear of fluids during microsurgery The dura is also open in a cruciate fashion. And again remembering that the STA will pass through the craniotomy and the dura to reach the peer. And therefore the dural opening and craniotomy should consider the transosseous and transdural route of the STA. Here's a donor vessel, a healthy and a large caliber one is isolated. Again, papaverine solution is used for irrigation, so that the lumen of the vessel is relaxed. Piece of colored plastic is used as the background to allow easier identification of the suture line. Small perforating vessels of this segment may need to be sacrificed. Here's a piece of gelfoam soaked in papaverine, placed on the recipient vessel while the end of the donor STA vessel is prepared. temporary clip was placed across the root of the STA. The distal end of the STA is now disconnected, while bipolar forceps are used to coagulate the end of the STA away from the end that will be used for anastomosis. Heparin irrigation is used to clear the lumen of the donor vessel. All the adamant tissue and soft tissues are cleared, from the end of the donor vessel. Again, the entire length of the STA is not prepared, just the end that will be used for anastomosis The end of the donor vessel is also fish mouthed, to enhance and expand the area of the anastomosis. Temporary clips are applied to the segment of the recipient vessel. And we're just about ready to start the arteriotomy on the M4 branch. Here You can see the arteriotomy. Five to six millimeter, is quite adequate. The arteriotomy should be as linear and non-jagged as possible. Small piece of tubing may be used to keep the lumen of the vessel patent and avoid placing sutures inadvertently on the wrong side or edge of the arteriotomy. I don't routinely use this tube anymore. This is one of our early cases. The arteriotomy was slightly expanded in this case. 9-O sutures were used to close the heel and the toe of the arteriotomy. Here's the suture for the heel Here's the suture for the toe of the arteriotomy and anastomosis The edges of the vessel are minimally manipulated to avoid any trauma to the edges of the arteriotomy or to the edges of the end of the donor vessel. Next I use 10-O interrupted suturing technique to complete the anastomosis on both sides of the arteriotomy. Some of the last sutures, may be placed before and not as laid down, so that adequate visualization of the lumen isn't available. Here's a nice anastomosis line on this edge of the arteriotomy. next, the donor vessel is mobilized, and the other anastomosis line is also complete and enclosed. Again interrupted sutures, 10-O sutures, are placed. I manipulate only the ends of the suture, not their midsection to avoid their breakage. Heparin irrigation is used during the entire process. Here's the final product. We'll go ahead and restore flow. Some bleeding from the anastomosis line is expected. Pieces of gelfoam are placed around the anastomotic line to achieve hemostasis, ICG angiogram demonstrates, a nice patent donor and recipient vessels. Obviously the dural closure, has to consider the transdural route of the donor vessel. And also the bone flap should be carefully designed to avoid any strangulation of the donor vessel. Here's the dural closure and the post-operative angiogram in this case demonstrates a very patent, robust STA. Providing ample amount of flow to the distal MCA branches. And this patient did not suffer from any ischemia and has not further suffered from any of her preoperative TIA episodes. Thank you.

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