January 16, 2015
There are circumstances where actually more than one vessel can be the cause of trigeminal neuralgia. This is particularly important when one large offending compressive vessel is found along the shoulder of the nerve, and discoloration is noted and often the surgeon may abandon looking further underneath or, just along the medial aspect of the nerve to find another offending vessel. So I do recommend that if you find a vessel that is along the superior shoulder of the nerve and it's very convincingly the cause of trigeminal neuralgia, you look further beneath, superficial, and also anterior to the nerve, just to see if there's another compressive vessel that could also be the secondary cause of trigeminal neuralgia. In other words, finding one convincing vessel does not necessarily mean that no further search for another vessel could be done. So let's go ahead and discuss the case of a 42-year-old male who presented with left sided V2 and V1 trigeminal neuralgia. As you can see on this axial MRI, there is, a hint of some vascular abnormality along the nerve on the left side, and potentially a vascular loop just above the nerve. This patient underwent a left-sided retromastoid craniotomy. You can see the dural opening along the transverse and sigmoid sinuses. And you can see the junction of the tentorium and petrous bone. You can see the large superior petrosal vein that I most often preserve as using dynamic retraction and the suction apparatus as a tool to perform dynamic retraction obviates, most often obviates the need for sacrifice of the vein. So here is the right-sided superior petrosal vein as well as the trigeminal nerve that is being exposed. The arachnoid membranes in their region often are very thick, and therefore the surgeon has to persist and identify the vascular loop underneath these very thick arachnoid membranes. Here, you can see that above the, or a vein, there is a large vascular loop causing a significant impression and discoloration. However, further inspection underneath the nerve, before we pad the first large artery, which we're doing here right now. So after we pad this one, we'll go ahead and look underneath the nerve and we'll be able to find another compressive vessel that could also be causing trigeminal neuralgia. You can see how I maneuver the Teflon to mobilize the superior cerebellar artery branch away from the superior shoulder of the nerve. However, further inspection along the more superficial and inferior aspect of the trigeminal nerve revealed another vessel that could potentially be the cause of trigeminal neuralgia. And it's best in this situation, to also mobilize and pad the artery to prevent any possible chance of pain recurrence in the circumstances.
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