April 21, 2016
This is a good video that describes microvascular decompression surgery for Hemifacial spasm and at the same time, review some of the management strategies to avoid complications and control bleeding from a torn Superior Petrosal Sinus. This is a 62 year-old female with longstanding right-sided hemifacial spasms. MRI evaluation revealed presence of a vascular loop at the area of the seven and eighth cranial nerve complex near the brainstem. Patient subsequently underwent a right-sided Retromastoid Craniotomy. Here's the exposure of the seven and eighth complex. Here's one of the distal vascular loops along the cisternal segment of the vessel, obviously most likely this is not the offending vessel. The offending vessel is much closer to the root exit zone of the seventh cranial nerve. However, as you can see, the vector of retraction should be parallel to the ninth cranial nerve and not parallel to the eighth cranial nerve to avoid any risk to the brainstem auditory evoked responses. In addition, because of the vitreous retraction was not appropriate, aggressive amount of cerebellar retraction was necessary, and this led to the avulsion of the superior petrosal sinus. One of my fellows was conducting this initial part of the operation. Here you can see the sudden gush of venous bleeding. This case appropriate help was summoned. I inspected the direction of the flow of the venous bleeding, suspected that the superior petrosal sinus was convulsed. Here you can see the location of the vein at the petrotentorial junction. The vein was coagulated. Bleeding was rarely controlled. Here you can see the tentorium bit respond, a very inferior to superior operative trajectory to reach this area that is not usually exposed during MVD for Hemifacial Spasm. Next the ninth cranial nerve was identified. Here you can see the vector of retraction is pretty much parallel to the ninth cranial nerve. Here's the root exits of the seventh cranial nerve. Here's the eighth, here's the seventh cranial nerve that discoloration at the root exit zone of the nerve is quite apparent. Here you can see the vascular dupe. Obviously the pathology is now found. Here's another look, at the discoloration at the level of the facial nerve near the brainstem. Piece of shredded Teflon is placed to create a barrier between the offending vessel and the root exits zone or the seventh cranial nerve further inspection reveals Northern sub other offending vessels around the nerve. Here's a final reconfiguration of the Teflon patch. Dynamic retraction is used to protect the eighth cranial nerve. In this case, because it was this relatively tortuous vessel and some distance between the vessel and the root exits on upon decompression, on mobilization of the artery. I use some fibrin glue to make sure that the Teflon patch is immobilized and is not going to be displaced in a delayed fashion. Here's the fiber and glue patching the Teflon implant down. This the final result of this operation. Here's a more demagnified view, all our operative corridor through the retro mastered approach, very small craniectomy was utilized in this case, you are a closure standard fashion in this case, watertight and the postoperative CT scan reveals the expected findings of a small Teflon patch without any other complicating features. And this patient made an excellent recovery with resolution of her preoperative hemifacial spasms. Thank you.
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