Microsurgical Resection of an Intracranial Dural Arteriovenous Fistula
Main Text
Table of Contents
Intracranial dural arteriovenous fistulas (dAVFs) are abnormal shunts between the meningeal arteries supplying the dura mater and the venous sinuses or cortical veins.1 These lesions represent 10–15% of all intracranial vascular malformations.2 DAVFs can be classified into different types based on their angioarchitecture and venous drainage patterns. Type I dAVFs involve a direct connection between the dural arteries and venous sinuses, with benign clinical outcomes.3 In contrast, types II, III, and IV dAVFs are associated with more aggressive features, such as retrograde venous drainage (RVD) and cortical venous reflux (CVR), and can lead to an aggressive clinical course, with a high risk of an intracranial hemorrhage, venous hypertension, and neurological deficits.4,5 Even in cases of dAVFs without CVR, treatment may be required for patients experiencing intolerable symptoms, such as severe headache, intractable tinnitus, ophthalmoplegia, and/or decreased vision.6
Endovascular embolization is frequently the first-line treatment for dAVFs, as it allows for targeted occlusion of the fistulous points with minimal invasiveness. However, in cases where endovascular approaches have failed or are deemed unsuitable due to the angioarchitecture of the fistula, microsurgical resection remains a viable and potentially curative option.7,8 This approach involves the precise identification and obliteration of the fistulous points and associated vessels, thereby eliminating the abnormal shunt and restoring normal cerebral hemodynamics.9
This video outlines the surgical steps involved in the microsurgical resection of an intracranial dAVF in a 74-year-old male patient, highlighting the importance of meticulous planning, intraoperative imaging, and precise dissection techniques. The patient has previously undergone embolization, but recurrence occurred despite the initial treatment and patient symptoms liked headaches and weakness restarted. A decision was made to perform microsurgical resection of dAVF. The video provides a comprehensive illustration of this procedure, emphasizing the value of microsurgery as a definitive treatment modality for these challenging clinical scenarios.
Preoperative imaging, such as computed tomography (CT) angiography is thoroughly reviewed to determine the location, angioarchitecture, and venous drainage patterns of the dAVF. The surgical procedure begins with patient positioning and preparation. The patient is set up in a supine position with the head higher than the heart level. A skin incision is made in a straightforward manner. The neuronavigation systems are employed to precisely localize the dAVF and plan the optimal craniotomy size and trajectory. To reach the surgical site, a solitary parietal burr hole is created at the predetermined position determined by preoperative imaging and surgical planning. The bone is carefully extracted using a craniotome, through a continuous circular incision that starts and ends at the burr hole. This creates a bone flap that can be temporarily repositioned during the procedure.
Upon completion of the craniotomy, the surgical team proceeds to elevate the flap, revealing unexpected adhesions that warranted a shift to microscopic visualization for enhanced control and clarity. Following the establishment of bleeding control, the surgical team proceeds with the opening of the dura mater. Upon opening the dura, the fistula points are found to be localized more laterally than anticipated. This unexpected anatomical presentation underscores the rationale for performing a wider dural opening, as the precise location of the fistula points cannot always be predicted with 100% accuracy.
However, the surgical procedure unfolds with an unexpected revelation. Upon the initial dural exposure, the two fistula points were immediately encountered, leading to their inadvertent sectioning during the dural opening. Despite this unforeseen occurrence, additional pathological vascular connections are identified. Intraoperative indocyanine green (ICG) angiography is employed to assess vascular flow within the identified vessels. By integrating fluorescence imaging with navigational guidance, the potential locations of fistulas are carefully examined for their anatomical significance. The confirmation of the drainage of veins and the supply of arteries helps to determine the exact locations for intervention. Subsequent excision is performed. The cessation of vascular perfusion in the draining veins, confirmed by ICG angiography, signifies the successful closure of the fistula points. Given the comprehensive nature of the surgical approach and the successful disruption of multiple pathological connections, the prognosis for the patient is deemed highly favorable.
After the successful resection of the dAVF, the final step involves closing the surgical site. The dura is carefully closed using sutures to prevent cerebrospinal fluid leakage. The previously removed bone flap is repositioned and secured in place using titanium plates and screws. The subcutaneous tissue and skin are closed in layers using absorbable and non-absorbable sutures, respectively.
The microsurgical resection of intracranial dAVFs is a complex and technically demanding procedure that requires a thorough understanding of cerebrovascular anatomy, advanced microsurgical skills, and the judicious use of intraoperative imaging modalities. The successful resection of the intracranial dAVF, in this case, underscores the value of microsurgery as a definitive treatment option, particularly in cases where endovascular embolization has failed. By precisely identifying and resecting the dAVF and its associated vessels, the risk of potentially life-threatening complications, such as intracranial hemorrhage or venous hypertension, is prevented. Furthermore, the video serves as an invaluable educational resource for neurosurgeons in training, as well as a reference for experienced practitioners. It emphasizes the importance of maintaining a high level of vigilance and adaptability during the procedure, as unexpected anatomical variations or adhesions may necessitate adjustments to the surgical approach. In conclusion, the microsurgical resection of intracranial dAVFs remains an important treatment method in the field of neurosurgery.
The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published online.
Citations
- Gupta A, Periakaruppan A. Intracranial dural arteriovenous fistulas: a review. Ind J Radiol Imag. 2009;19(1). doi:10.4103/0971-3026.45344.
- Gandhi D, Chen J, Pearl M, Huang J, Gemmete JJ, Kathuria S. Intracranial dural arteriovenous fistulas: classification, imaging findings, and treatment. Am J Neuroradiol. 2012;33(6). doi:10.3174/ajnr.A2798.
- Borden JA, Wu JK, Shucart WA. A proposed classification for spinal and cranial dural arteriovenous fistulous malformations and implications for treatment. J Neurosurg. 1995;82(2). doi:10.3171/jns.1995.82.2.0166.
- Natarajan SK, Ghodke B, Kim LJ, Hallam DK, Britz GW, Sekhar LN. Multimodality treatment of intracranial dural arteriovenous fistulas in the onyx era: a single center experience. World Neurosurg. 2010;73(4). doi:10.1016/j.wneu.2010.01.009.
- Baharvahdat H, Ooi YC, Kim WJ, Mowla A, Coon AL, Colby GP. Updates in the management of cranial dural arteriovenous fistula. Stroke Vasc Neurol. 2020;5(1). doi:10.1136/svn-2019-000269.
- Choi JH, Jo K Il, Kim KH, et al. Spontaneous angiographic changes in venous drainage patterns related to symptom changes in patients with untreated cavernous sinus dural arteriovenous fistula. Neuroradiology. 2015;57(11). doi:10.1007/s00234-015-1597-2.
- Gross BA, Albuquerque FC, Moon K, McDougall CG. The road less traveled: transarterial embolization of dural arteriovenous fistulas via the ascending pharyngeal artery. J Neurointerv Surg. 2017;9(1). doi:10.1136/neurintsurg-2016-012488.
- Oh SH, Choi JH, Kim BS, Lee KS, Shin YS. Treatment outcomes according to various treatment modalities for intracranial dural arteriovenous fistulas in the onyx era: a 10-year single-center experience. World Neurosurg. 2019;126. doi:10.1016/j.wneu.2019.02.173.
- Sugiyama T, Nakayama N, Ushikoshi S, et al. Complication rate, cure rate, and long-term outcomes of microsurgery for intracranial dural arteriovenous fistulae: a multicenter series and systematic review. Neurosurg Rev. 2021;44(1). doi:10.1007/s10143-019-01232-y.
Cite this article
Czabanka M. Microsurgical resection of an intracranial dural arteriovenous fistula. J Med Insight. 2024;2024(148). doi:10.24296/jomi/148.
Procedure Outline
Table of Contents
- Preparation
- Incision
- Use Navigation to Adjust Approach
- Drill Burr Hole
- Use Craniotome and Remove Bone Flap
- Open Dura
- Widen Exposure
- Identify Fistula
- Use ICG Angiography and Dissect Bridging Veins
- Cauterize and Dissect Fistulized Veins
- Close Dura
- Refix Bone Flap
- Wound Closure
Transcription
CHAPTER 1
Hello, my name is Marcus Czabanka. Today, we are going to operate an arteriovenous fistula in a 74-year-old patient. Here, you can see the images over there. Here, you can see the feeding of this fistula over here via the external carotid artery. And the reason why we operate on this patient is because the patient was embolized before in 2002, and they couldn't really achieve a complete occlusion, and now it has really grown since then. So, the indication now is to microsurgically resect the fistula. For this purpose, we going to do five steps. The first step obviously will be the craniotomy and the approach. The second step will be wide opening of the dura to see as much space as possible. Third step then will be an intraoperative angiography to visualize the fistula. And then the fourth step, we're going to coagulate and cut the fistula, which is then followed by the fifth step, which is the closing of the operative field.
CHAPTER 2
Okay, so. We have two – that's a 74-year-old patient with an AV fistula. It was embolized already before, but it recurred. And you can see the two major fistula points on the – on the CT angio that we navigated. One is up here, and the other one should be down here. So, we're going to make our approach right here, then make a rather big one left-sided osteoplastic craniotomy. And then we go look for the fistula, and then we are going to close it. That's our – that's our idea. Yeah, and we're going to start now. Okay, that's our surgical setup. So, we do the skin incision. Okay. Use a very simple straight cut. Okay, that's our approach. I'm going to use the navigation now to show where we're going to do our burr holes and where we're going to plan to do the craniotomy. Okay, you can see – you can see on the left – on the lower row, the left image. You can see the two fistula points, so actually we're going to do our craniotomy a little larger than that, so we have more space. So, we're going to do one burr hole here. Nice. Okay. Okay here, and the other one. Yeah okay, the other one there. So I'm – I'm about to save this bone to pull it back into the burr holes when we close. It's always - gets a mess over this sinus, especially if the patients are older. Okay now we lift the flap after we did the craniotomy. So we put something on the sinus to cover it. I see. Okay. It's interesting. Okay, that's something I didn't expect – all these adhesions. So, I'm going to switch now to the microscope. So I didn't expect these adhesions in these ways, so I prefer to change to the microscope – to have better control and better visualization.
CHAPTER 3
Okay. Okay, now we have some control over the bleeding, so we continue with our opening of the dura. So, now we've done the approach. Now it would be nice to really identify the fistula. Here. There – there they were – these were the fistulas already, right there. We changed them when we opened the dura. That's one way of doing it. There you go. See this? They were not in the midline, but they were over here. I expected the fistula to be more in the midline, but the fistula was actually so far lateral, that I did cut the fistula when I opened the dura. Here we can see some remnants of the fistula, so we're going to check them. So we are going to check the flow in these – in these vessels with ICG angiography. Okay, since I really cannot 100% identify the two major fistula points – there we go. So for this vascular intra – for this intraoperative vascular diagnostic, we use fluorescence, and then we're going to check whether here's the arterial supply. We've already changed the microscope to the fluorescent filter. And I'm also going to use the navigation to check if that might be the point. That should be too deep. Yeah. Perfect. Let's see – yeah, that's draining, that's a draining vein. Just to show you where we are – we are right here on the posterior right. Okay, let's go back. Ah, there we go. Here we might also have a candidate – and here. Oh, here. Okay, cut this vein. Then I cut. Then I cut this vein. Okay, so I think that's it. See, that's the big vein – it's draining over there. Nice. But here, we cut it already. There you go, so it's not draining anymore. Good. Okay that's – so we have cut all the connections in this area between the – the dura and the – and the brain, and we have shown with the ICG that the big draining vein is not perfused anymore. So, surgery should be finished now. We're just going to close. And that's it.
CHAPTER 4
When we opened the dura, they were localized more laterally than I expected them to be. I thought they would be more in the midline, but that's how it is. That's also the reason why... Why we – why we opened the dura over a larger area, because we never can 100% predict where the fistula point really is. But that was interesting – see all the vessels – when I opened the dura, all the vessels that were I think the major feeding vessels. But I expected them to be here, but they were over here. Because – this you cannot always – you cannot say 100% on the angio where the fistula exactly is. So, that's the reason why you have to do big openings – or bigger openings – for these kind of surgeries. Okay, now we close it. That's okay. So now we start – that's the closure. So we put in the bone flap. And now we do the subcutaneous suturing.
CHAPTER 5
The end result of the surgery was good. So we did see in the intraoperative angiography that the big draining vein was not filling anymore, and we were able to cut it. Surgery had one surprise. I think the major surprise was that when we opened the dura, we had already encountered the two fistula points, and we already cut the fistula points by opening the dura. We found other connections between the dura and the brain, and we were able to cut them out, either, so I think the chances are very good that the fistula will be treated now and cured for that patient.