Journal of Clinical Neuroscience 68 (2019) 333–335 Contents lists available at ScienceDirect Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn Tools and techniques Craniotomy and direct access microcatheterization for preoperative embolization of a complex, high grade intracranial arteriovenous malformation Daniel M.S. Raper, David Asuzu, M. Yashar S. Kalani, Min S. Park ⇑ Department of Neurosurgery, University of Virginia, Charlottesville, VA, USA a r t i c l e i n f o Article history: Received 30 March 2019 Accepted 27 May 2019 Keywords: Arteriovenous malformation Endovascular Onyx Surgical technique Transarterial embolization a b s t r a c t The optimal management of complex, Spetzler-Martin Grade 5 arteriovenous malformations (AVMs) remains a challenge, despite the availability of endovascular, surgical and radiosurgical treatment options. In cases requiring treatment due to progressive neurological deficit or recurrent hemorrhage, preoperative embolization may be an extremely useful adjunct to definitive surgical resection, and is usually accomplished via the transarterial route using liquid embolysate. However, this treatment approach often mandates access to distal arterial pedicles that can be technically challenging by standard endovascular approaches. This video describes a left parietal craniotomy for direct access microcatheterization and embolization of an otherwise endovascularly inaccessible Spetzler-Martin Grade 5 AVM prior to definitive surgical resection. The case was performed in the hybrid operative suite with biplane intraoperative angiography. Technical considerations, operative nuances and outcomes are reviewed. Ó 2019 Elsevier Ltd. All rights reserved. 1. Case report A 64 year old man with a history of a left parieto-occipital AVM, previously treated 10 years ago with staged partial embolization and staged stereotactic radiosurgery, presented with three episodes of low volume intraventricular hemorrhage over the course of 1 month. He had mild left sided weakness and a partial right homonymous hemianopsia. Imaging revealed moderate volume IVH, as well as post-procedural changes from prior partial Onyx embolization of the AVM. DSA revealed a large residual left parieto-occipital AVM, fed by enlarged distal left MCA branches, left pericallosal and callosomarginal arteries, and enlarged distal left PCA branches, with minor contribution from a left posterior choroidal artery and bilateral middle meningeal arteries. There was both superficial and deep venous drainage via ectatcic, dilated draining veins Fig. 1. After multidisciplinary discussion, a strategy of craniotomy and staged, direct stick partial embolization was devised. Surgical indications for this patient were: 1) High grade AVM with recurrent IVH, which was 2) unable to be treated via traditional endovascular means. The planned procedure was a combined procedure in the OR with intraoperative biplane angiography, utilizing a craniotomy ⇑ Corresponding author at: Department of Neurosurgery, University of Virginia Health System, Box 800212, Charlottesville, VA 22908, USA. E-mail address: mp2tq@hscmail.mcc.virginia.edu (M.S. Park). https://doi.org/10.1016/j.jocn.2019.05.052 0967-5868/Ó 2019 Elsevier Ltd. All rights reserved. with a view to direct stick microcatheterization of the major distal MCA arterial pedicle. This allowed the surgical team the ability to continue with traditional open surgical resection if necessary, and served as the first stage of a staged approach with the goal of safe, total resection of the AVM. A long 5F arterial sheath was placed in the left common femoral artery prior to positioning. The patient was positioned in the lateral park bench position with the left parietal area exposed, and a U shaped incision was planned using stereotactic neuronavigation. Neuromonitoring leads were placed for measurement of SSEPs, MEPs, and EEG. A left parietal paramedian craniotomy was turned in the usual fashion and the dura was opened to expose the AVM. ICG angiography revealed that a large cortical vein traversing the surgical field continued to drain in the venous phase, indicating that it was an important vein involved in drainage of normal functional brain and must be preserved. ICG also confirmed the distal MCA pedicle that we had identified on the preoperative DSA, which branched to give supply to a posterolateral portion of the AVM. The proximal trunk of this vessel was first dissected circumferentially, and a temporary aneurysm clip was placed on the vessel while the patient was monitored for 15 min for changes in neuromonitoring. After this time, the temporary clip was replaced for a permanent AVM clip. Temporary clips were then placed on each of the distal MCA branches, and these were also circumferentially dissected. A #4-0 Nurolon tie was looped around the proximal vessel in order to secure the microcatheter around the arteriotomy site. Next, an 334 D.M.S. Raper et al. / Journal of Clinical Neuroscience 68 (2019) 333–335 Fig. 1. A middle-aged patient with a history of a left parieto-occipital AVM, previously treated 10 years ago with staged partial embolization and staged stereotactic radiosurgery, presented with three episodes of low volume intraventricular hemorrhage over the course of 1 month. This was associated with mild left sided weakness and a partial right homonymous hemianopsia. Imaging revealed moderate volume IVH (A), as well as post-procedural changes from prior partial Onyx embolization of the AVM (B). DSA revealed a large residual left parieto-occipital AVM, fed by enlarged distal left MCA branches, left pericallosal and callosomarginal arteries, and enlarged distal left PCA branches, with minor contribution from a left posterior choroidal artery and bilateral middle meningeal arteries (C). There was both superficial and deep venous drainage via ectatcic, dilated draining veins. After multidisciplinary discussion, a strategy of craniotomy and staged, direct stick partial embolization was devised. The patient was taken to the hybrid OR with intraoperative biplane angiography, where a parietal craniotomy was performed to expose the AVM (D). ICG confirmed the distal MCA pedicle that had been identified on the preoperative DSA, which branched to give supply to a posterolateral portion of the AVM (E). Embolization using Onyx liquid embolysate was performed through direct access to this superficial arterial pedicle. Follow-up DSA demonstrated decreased filling of the posterolateral portion of the AVM (F; comparison of pre- and post-embolization Onyx cast (G, H)). The patient had an unremarkable postoperative course, and was discharged home at his neurological baseline, with a plan to return for subsequent staged direct stick microcatheterization of another MCA pedicle, prior to definitive surgical resection. arterioromy was made in the proximal vessel, and a Marathon microcatheter was advanced under direct vision into the distal branch vessel that directly fed the AVM. Gentle pressure on the outside of the artery with the forceps was used to direct the microcatheter into the appropriate distal branch. Next, the temporary clip on this branch was removed and used to secure the Nurolon tie around the arteriotomy site, securing the microcatheter in place. This clip also functioned to prevent reflux of Onyx. The microcatheter was then further secured with multiple Nurolon ties and staples. At this point, the patient was positioned in the biplane unit and the endovascular portion of the case was performed. Microcatheter injection confirmed that the microcatheter was appropriately positioned within a distal MCA branch feeding the AVM. The clips on the feeding and branch vessel are seen on the subtracted angiographic view and function as a guide to the acceptable extent of reflux of embolysate during the embolization. Embolization using Onyx-18 liquid embolysate was then performed in the standard fashion. Following embolization, unsubtracted fluoroscopic images demonstrate the portion of additional AVM that was able to be embolized. A small amount of reflux of Onyx was seen in the surgical field, which was easily removed with irrigation. The vessels have been expanded by the injection of Onyx embolysate. The microcatheter was then removed, and he craniotomy was closed in the standard fashion. Follow-up DSA demonstrated decreased filling of the posterolateral portion of the AVM. The patient had an unremarkable postoperative course, and was discharged home at his neurological baseline, with a plan to return for subsequent staged direct access microcatheterization of another MCA pedicle, prior to definitive surgical resection. 2. Conclusion The optimal management of complex, Spetzler-Martin Grade 5 arteriovenous malformations (AVMs) remains challenging, despite D.M.S. Raper et al. / Journal of Clinical Neuroscience 68 (2019) 333–335 the availability of endovascular, surgical and radiosurgical treatment options. A combined multimodality surgical and endovascular treatment approach such as the one described in this report allows for more distal penetration of embolysate into difficult to access AVMs, while minimizing the risks associated with reflux and unintended branch occlusion. 335 Funding received None. Declaration of Competing Interest None. 3. Declaration Appendix A. Supplementary data All authors warrant that written release has been obtained prior to submission, from the patient who appears in this surgical video. Should the Journal or Publisher request copies of this written release, we shall provide it in a timely manner. Supplementary data to this article can be found online at https://doi.org/10.1016/j.jocn.2019.05.052.