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Original research
Endovascular treatment for traumatic scalp arteriovenous fistulas: results with Onyx embolization
  1. Guilherme Dabus,
  2. Raffaella Pizzolato,
  3. Eugene Lin,
  4. Andreas Kreusch,
  5. Italo Linfante
  1. Division of NeuroInterventional Surgery, Baptist Cardiac and Vascular Institute and Baptist Neuroscience Center, Miami, Florida, USA
  1. Correspondence to Dr G Dabus, Division of NeuroInterventional Surgery, Baptist Cardiac and Vascular Institute, 8900 N Kendall Drive, Miami, FL 33176, USA; guilhermed{at}baptisthealth.net

Abstract

Background Arteriovenous fistulas of the scalp (S-AVFs) are rare lesions and may occur spontaneously or secondary to trauma. The use of Onyx for the treatment of S-AVFs is not well established at this time. We discuss three cases of traumatic S-AVFs treated successfully with Onyx embolization alone or in association with coils.

Methods The database of patients treated at the Baptist Cardiac and Vascular Institute, Miami, Florida, was reviewed. All patients with traumatic S-AVFs treated with Onyx were included.

Results Two men and one woman with progressive enlarging pulsatile mass with bruit or tinnitus had angiographic evidence of S-AVF and were treated. In two patients the S-AVFs were secondary to hair transplantation. They were treated with Onyx-18 embolization as the single treatment modality. One patient with S-AVF resulting from temporomandibular joint arthroscopy was treated with coils and subsequent Onyx-34 embolization. In one patient, transarterial microcatheterization and injection of Onyx-18 was performed. In another patient, the intra-arterial approach was prevented by arterial vessel tortuosity. Therefore, access to the fistula was obtained through direct puncture of a large frontal vein; contrast injection confirmed the positioning of the needle within the draining vein of the AVF and Onyx-18 was then injected while the outflow vein was compressed. In the third patient in this series, coils were deployed to allow safer and more controlled injection of Onyx-34. No procedure related complications were noted. Post-embolization angiography demonstrated successful and complete occlusion of the AVF immediately after treatment. Follow-up revealed complete resolution of the symptoms.

Conclusions Our experience in this small series indicates that endovascular treatment of S-AVFs with Onyx is rapid, safe, and highly effective.

  • Arteriovenous Malformation
  • Embolic
  • Fistula
  • Intervention
  • Liquid Embolic Material

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Introduction

Arteriovenous fistulas of the scalp (S-AVFs) (known also as cirsoid aneurysms) are rare abnormal arteriovenous communications between arterial branches from the external carotid artery and draining veins within the subcutaneous fatty layer of the scalp. They may occur spontaneously or secondary to a variety of traumas. Hair transplantation, arthroscopic temporomandibular joint (TMJ) surgery, and acupuncture are several of the known causes of traumatic S-AVFs. They result in a deforming pulsatile mass associated with bruits, tinnitus, headaches, local pain, epilepsy,1 hemorrhage, and scalp necrosis. In the past, surgery was the primary treatment for these lesions, alone2–12 or in combination with endovascular treatment.13 ,14 Endovascular embolization has been used with increasing frequency as the initial treatment of head and neck vascular lesions.15–22 Onyx is a non-adhesive viscous embolic agent approved by the Food and Drug Administration for the treatment of intracranial arteriovenous malformations. Its use for S-AVFs has not been well established.

In this report, we describe three cases of traumatic S-AVFs successfully treated with Onyx embolization as the sole treatment modality or as an adjunct after coil deployment.

Methods

The database of patients treated at the Baptist Cardiac and Vascular Institute, Miami, Florida, was reviewed. Approval from our institutional review board was obtained. All patients with traumatic S-AVFs that were treated with Onyx were included.

Results

Between 2010 and 2012, three consecutive patients with traumatic S-AVFs were treated with Onyx embolization as a single treatment modality or in combination with coil placement at our institution. Two patients developed S-AVFs as a complication of hair transplantation. Another patient developed the S-AVF after arthroscopic TMJ surgery. All patients presented with a progressive enlarging pulsatile mass with associated bruit or tinnitus.

Case No 1

A man in his early 30s presented with an enlarging pulsating mass of his left forehead and an increasingly audible bruit. His only medical history was undergoing hair implantation at the age of 28 years. On examination he was found to have a prominent and painless left scalp pulsatile mass with an audible bruit at one of the sites of the hair transplant (figure 1).

Figure 1

The patient presented, post hair transplant, with an enlarging pulsating mass of his left forehead and an increasingly audible bruit. CT angiography (A) revealed the presence of a vascular conglomerate, suspicious for an arteriovenous fistula of the scalp (S-AVF) (arrow). (B) Left external carotid injection confirming the presence of an S-AVF (arrow). The lesion was accessed through direct puncture (C). (D) Post-embolization angiogram confirming complete occlusion of the AVF.

Selective internal and external angiography demonstrated the presence of a hyperplastic, tortuous, left superficial temporal artery with communication to a large left superficial frontotemporal vein. Treatment of the AVF was initially attempted by the intra-arterial approach. However, the tortuosity of the superficial temporal artery prevented access with a microcatheter to the fistula. Given the location of the AVF, access was then obtained through direct puncture of a large frontal vein with a 21 G butterfly needle. Contrast injection confirmed the positioning of the needle within the draining vein close to the fistulous connection. Onyx-18 liquid embolic material was then injected while the vein was compressed to successfully close the draining vein and, retrogradely, fill the fistulous connection and the feeding artery.

Post-embolization external carotid angiography demonstrated complete occlusion of the AVF. A 5 month follow-up visit demonstrated complete resolution of the pulsatile mass on the forehead with no evidence of bruit.

Case No 2

A man in his early 40s presented to the emergency department with a progressively growing pulsatile occipital mass, with a bruit noted especially when he was attempting to sleep on his right side. The only medical history was a hair transplant done 2 months prior to presentation. CT angiography of the head and neck demonstrated a mass of serpiginous vessels superficial to the right occipital bone in the scalp (figure 2).

Figure 2

The patient presented, post hair transplant, with an enlarging pulsating mass of his right occipital region and an increasingly audible bruit. CT angiography demonstrated a mass of serpiginous vessels superficial to the right occipital bone in the scalp (A). (B) Right external carotid injection confirming the presence of an arteriovenous fistula of the scalp (S-AVF) (single arrow). Note that there is transosseous drainage into the right sigmoid sinus (double arrows). (C) Post-embolization angiogram confirming complete occlusion of the AVF.

He underwent selective internal and external angiography that confirmed the presence of an S-AVF localized in the occipital region with the arterial supply predominantly from a branch of the right occipital artery in addition to inflow from the left occipital artery. Superselective angiography was performed with a microcatheter which was positioned in the distal branch of the right occipital artery at the level of the fistulous connection. Onyx-18 liquid embolic material was then injected to successfully close the AVF.

Post-embolization bilateral carotid angiography demonstrated complete occlusion of the AVF immediately after Onyx-18. A 2 month follow-up visit demonstrated complete resolution of the pulsatile mass with no evidence of bruit.

Case No 3

A woman in her early 60s underwent bilateral TMJ arthroscopy. The only complication noted during the procedure was bleeding from the left TMJ. Over the course of 3 months after her operation, she developed left-sided pulsatile tinnitus with noted a palpable fistula in the left preauricular area. CT and CT angiogram of the head and neck demonstrated an AVF from the left superficial temporal artery to the left superficial temporal vein at the level just lateral to the left TMJ (figure 3).

Figure 3

The patient presented, post temporomandibular joint arthroscopy, with pulsatile tinnitus and bruit over the left temporal region. CT angiography (A) and diagnostic cerebral angiography (B) were performed demonstrating the presence of an AVF (arrow in A and B). (C) Immediate complete occlusion of the AVF post-embolization. The symptoms resolved immediately. At the 1 year follow-up, the patient was symptom free and diagnostic cerebral angiography revealed no evidence of recurrence (D).

Selective internal and external angiography was subsequently performed that confirmed the presence of a large AVF arising from the left superficial temporal artery and draining into a large superficial temporal vein that ultimately drained into the left jugular vein. Superselective angiography was performed with a microcatheter that was advanced and positioned within the superficial temporal artery. A total of three coils were than deployed in the foot of the draining vein to decrease flow, allowing for safer and more controlled injection of liquid embolic agent. Onyx-34 was then injected through the microcatheter to completely occlude the fistula which was confirmed by post-embolization angiography. Her pulsatile tinnitus resolved immediately after the procedure. Follow-up cerebral angiographies at 1 year demonstrated no recurrence of the AVF.

Discussion

Scalp AVFs are uncommon lesions and therefore most of the literature consists of case reports and small case series.1–25 These may occur spontaneously or secondary to a variety of traumas. Hair transplantation and arthroscopic TMJ surgery are some of the known causes of traumatic S-AVFs. They result in a deforming pulsatile mass associated with bruits, tinnitus, headaches, local pain, epilepsy,1 hemorrhage, and scalp necrosis. In the past, surgery was the primary treatment for these lesions, alone2–12 or in combination with endovascular treatment.13 ,14

Hair transplantation is an increasingly popular cosmetic treatment as more than 1.2 billion people are affected by baldness.23 The punch autograft technique is the main technique used and it is considered simple, effective, and safe.3 ,17 In addition, TMJ arthroscopy is largely used for the treatment of TMJ pain and dysfunction. These procedures have been associated with complications, including vascular injuries, which may result in the development of an AVF when both the artery and vein are damaged during the procedure.12 ,17 ,23 ,24

Definitive treatment for these vascular lesions requires occlusion of the arteriovenous shunt. Over the years, different endovascular approaches (ie, transarterial, transvenous, and direct puncture routes) and various embolic agents have been used for the treatment of AVFs as a single modality15–17 ,19 or associated with surgery,13 ,18 with enthusiastic results. Endovascular procedures have gained attention because they allow treatment of vascular lesions at the time of diagnosis. Furthermore, these procedures are less invasive than surgery, which can be complicated, especially for patients with large lesions due to considerable blood loss and an associated large resection area necessitating reconstructive skin procedures.17 Therefore, endovascular embolization has been adopted in our service as the primary modality for the treatment of AVFs. In this study, we reported three cases of traumatic S-AVFs completely cured after endovascular treatment using Onyx. Onyx is a non-adhesive liquid embolic agent (ethylene-vinyl alcohol) dissolved in an organic solvent dimethyl sulfoxide.26 ,27 Its major advantage compared with other liquid embolic agents, such as n-butyl-2-cyanoacrylate, is non-adhesivity and increased predictability and control of deposition, which allows longer injections with controlled reflux and better penetration of the vascular channels.26 ,27 Our results indicate that treatment with Onyx embolization, alone or in combination with coil placement, is safe and effective.

In 2007, Arat et al18 reported nine cases of Onyx embolization of craniofacial vascular malformations, six with AVFs and three with arteriovenous malformations. They gained successful results in treating all AVFs; however, the outcome was less favorable for the three patients with arteriovenous malformations. Recently, Dalyai et al19 described a patient with an S-AVF with a diffuse, serpiginous arterial supply that precluded a transarterial approach. It was successfully embolized exclusively via a femoral transvenous retrograde approach using Onyx with balloon protection. Follow-up angiography at 9 months confirmed complete and persistent angiographic cure of the S-AVF, and CT angiography at 1 year showed persistent resolution of the fistulous vessels. Moreover, Thiex et al20 reported 22 patients with extracranial vascular anomalies, three of whom had traumatic AVFs. They achieved complete embolization with a single stage of Onyx alone in two patients and Onyx after deployment of detachable coils in one patient. The efficacy of the combined Onyx and coil embolization was also described by Burrus et al25 and Dabus et al.28 One of the concerns with regard to Onyx embolization is radiation exposure. In our series, there were no cases of postprocedural alopecia encountered.

The S-AVF approach may be hampered by extreme tortuosity of the external carotid branches. In these cases the fistulous point can be accessed using direct percutaneous puncture and the liquid embolic agent can be safely injected, compressing the venous outflow, allowing retrograde filling of the arterial feeders.29 The effect of the embolization in occluding the AVF and in resolving the initial clinical symptoms is immediate, without the need for multistage embolizations. In our series, no procedure related complications were recorded. At follow-up, none of the symptoms had recurred.

Conclusion

Our small series of patients indicates that endovascular treatment of S-AVFs with Onyx through transarterial or direct puncture is rapid, safe, and highly effective. Additional studies to confirm our findings and to evaluate recurrence in a longer follow-up period are warranted.

References

Footnotes

  • Contributors GD and IL: study concept and design. GD, IL, RP, EL, and AK: acquisition of the data. GD, RP, EL and IL: analysis and interpretation of the data. GD, IL, RP, and EL: drafting of the manuscript. GD and IL: critical revision of the manuscript for important intellectual content. RP, EL, AK, GD, and IL: administrative, technical, and material support. IL and GD: study supervision.

  • Competing interests GD is a consultant for Codman Neurovascular, Covidien Neurovascular, and Reverse Medical. IL is a consultant for Covidien Neurovascular and Stryker.

  • Ethics approval The study was approved by the institutional review board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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