January 07, 2016
Supraorbital craniotomy through the eyebrow incision is quite effective for reaching lesions along the anterior skull base and parasellar areas. I'm going to use the case of one of my patients, a 52 year-old male, who presented with severe headaches but no evidence of hemorrhage on CT or lumbar puncture. However, on CT angiogram was noted to have questionable vascular abnormality along the anterior skull base. And a subsequent angiogram demonstrated an early draining vein as you can see at the tip of my arrow, most consistent with ethmoidal arteriovenous fistula. The 3D angiogram here can also elucidate this early draining vein along the anterior aspect of the faux. Because of the evidence of early cortical venous drainage, the risk of intracranial hemorrhage was noted to be significant. And therefore this patient underwent disconnection of his fistula. This small lesion along the anterior faux is quite ideal for an eyebrow incision. The patient is placed in supine position in the skull clamp. The incision for the eyebrow is just above the eyebrows, you can see not within the eyebrow. As coagulation of the follicles in the subcutaneous space during the incision can cause Alopecia, if the incision is made directly in the eyebrow. Also the supraorbital notch is identified and incision is placed just lateral to the notch, the incision is extended just slightly more laterally. This slight extension of incision provides ample amount of space for the key hole for placement of the burr hole. It is quite cosmetically acceptable as well. The head is turned approximately 45 degrees or slightly more in this case because we're trying to reach the anterior midline. Incision is completed just above the eyebrow. If the coagulation within a subcutaneous spaces minimize as much as possible, a Colorado needle on the bovie cautery is used to avoid aggressive coagulation of the subcutaneous structures and incision is extended all the way to the bone and the pericranium, which joins the Periorbital just around the rim is also disconnected. The supraorbital nerve is identified, released and obviously protected. The nerve has to be unroofed. So it can be released. Every few millimeter of incision here is quite important for extending reach of the craniotomy. The superior temporal line is illustrated here. Here's the handling of the fat pad. The frontalis branches of the facial nerve are most likely coarsening in this direction and therefore I cut the soft tissues anterior to them. Here's the area of the keyhole. Here's the frontal parts of zygoma. Most likely these are some of the branches of the frontalis nerve that are being protected. Dissection is kept just anterior to that. And here's the reflection of the fat pad posteriorly and also unveiling of the keyhole for placement of the initial burr hole. A lumbar drain was used in this case to decompress the dura over the initial burr hole caused a small tear in the dura. The craniotomy here does not require removal of the orbital rim as we're directing our attention into the really more medially and the lesion is very anterior. Therefore the rim was not removed as the lesion was not along the parasellar area. Small supraorbital craniotomy is elevated. After elusion of the bone flap, you can appreciate the exposure. You can see various number of fish hooks that mobilize the scalp as much as possible. Here's elevation of their frontal lobe gently. Stealth was used to identify the location of the fistula using CT angiogram. Dynamic retraction is necessary now to expose the medial aspect of faux, which should be just about here. You can see there arterialized draining vein, as well as some of the fistula within the faux. I'm going to go ahead and disconnect the vein here that most likely is arterialized and also coagulate some of the feeders within the faux. It was another vein that was suspicious, slightly more anteriorly and inferiorly that was disconnected. Here is an artery within the faux, which is most likely part of the fistula. The postoperative angiogram revealed no further residual early draining vein. And this patient was discharged on the first post operative day without any complications or discomfort often associated with arterial craniotomy due to disconnection of the temporalis muscle. Thank you.
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