January 17, 2015
Posterior fossa surgery for management of glossopharyngeal neuralgia involves transection of cranial nerve nine and microvascular decompression of cranial nerve 10. In this video the neuralgia technique for integral entry-drill dissection is discussed. This is a case of a patient of mine who is a 52 year old male who presented with long standing left sided glossopharyngeal neuralgia. On MRI of the posterior fossa, he demonstrated evidence of vascular loop on the left side, as well as, the right side. He convincingly had symptoms of glossopharyngeal neuralgia with typical triggers and therefore underwent a left sided retro mastoid craniotomy. Here's the incision. The patient is first position in a latter position. The Indian is identified. The root of zygomas identified. A line that joins the two. It estimates the location of the transfer sinus. The mastoid tip and the master group is identified. The groove of the mastoid aligned parallel to that and over it where it crosses the transfer sinus most likely signifies the location of the transfer sigma junction. And therefore we plan a curvilinear incision just below the transfer sigmoid junction. Following completion of the curvilinear incision and reflection of the myocutaneous flap inferiorly. Here you can see a left sided, retro mastoid CP-angle approach. Here's the Pietra spawn turning into the floor of the poster fossa. This is a landmark we use to reach the lower cranial nerves. You can see cranial nerve nine and cranial nerve 10 rootlets. We'll go ahead and do generous microdissection of their acne membranes. You can see cranial nerve nine. That is very distinctly separate from the rest of the lower cranial nerves. You can see the vascular loop, that is very apparent, causing conflict with a knife cranial nerve. We'll go ahead and coagulate and cut the knife nerve close to the brain stem, and we proceed to move the vascular loop, which was close to the choroid plexus that you saw a moment ago. We go ahead and work between the rootless of 10. This is really a nice image of the exit zone of cranial nerve 10 and evidence of discoloration in this area of the nerve. Most likely caused by the neurovascular conflict at the level of the exit zone of the nerve. Here's another rootlet of the 10th cranial nerve. So we're gonna go ahead and decompress both these with shredder piece of Teflon. First, we mobilize the artery, make sure all the perforators are protected. Here is the lower rootlets of 10. I do not transect any of the rootlets of cranial nerve 10 due to risk of swallowing difficulty. We'll go ahead and place a small piece of shredded Teflon between the lower rootlets. And after this vessel is decompressed, we dive our attention to the upper rootlets. So here you can see the artery is rolled over the smaller piece of Teflon. Now we're going to go ahead and put additional piece of Teflon to decompress the brainstem at the level of the upper rootlets. You can see dynamics, retraction, ellos, a very nice exposure of the root exit zone of the tenth cranial nerve without excessive retraction of the surrounding cerebella. Here's really a generous padding and mobilization of the artery over multiple pieces of shredded Teflon. The nerve itself is also insulated. You can see the anatomy of the hypoglossal nerve inferiorly and here is literally the final product, which demonstrates the pathology has been carefully found and decompressed. Here's a higher magnification view of what the product of this decompression should look like. This is a more de-magnified view at the end of the operation. The dura is approximated. The mastoid air cells are generously waxed. A cranioplasty performed and the closure is performed in standard fashion.
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