Solved on SIR Connect Feedback on mandibular AVM treatment

This column summarizes patient cases posted to SIR Connect (SIR’s popular online member community), the responses from other SIR members and how that feedback helped the original poster. To see how SIR’s online community can help you, visit SIR Connect at connect.sirweb.org.

Original Post, lightly edited for flow:

bit.ly/34yWViM

The patient is a 14-year-old girl who presented with a left mandibular arteriovenous malformation (AVM) (Cho II/Yakes IIIB). Her symptoms included bleeding and dental problems. The nidus of the AVM is in the body of the mandible where there is a large venous lake with drainage into the left internal jugular vein (IJV). Arterial supply is via the inferior alveolar and facial arteries. In addition to IR, ENT and oral surgery are involved with this case. How would you treat this patient?

What challenges have you faced in treating these lesions?

I still haven't treated this particular AVM. I am planning treatment with ear, nose and throat and oral and maxillofacial surgery. The biggest challenge is safely accessing the large venous lake inside the mandible. Our options include a retrograde transvenous approach through the IJV and direct access through the mandible. Based on feedback from the SIR Connect community, I’ve decided to take a direct access approach.

What prompted you to reach out regarding this case?

Since this will be the first mandibular AVM I’ve treated, I sought advice from more experienced interventionalists. SIR Connect is the next best thing to practicing in an academic setting where such advice can be obtained in person.

What post or posts were most valuable to you and why?

I found them all useful. Joseph Gemmete, MD, FSIR, Brian Strife, MD, and Andrew Maleson, MD, each provided very practical advice regarding access, visualization and embolization. Dr. Strife shared an informative publication on ethanol embolization of AVM.6 My therapeutic plan for this case was guided, in large part, by discussions on SIR Connect.

Additional commentary

Vascular malformations are currently subdivided by their hemodynamic properties, type of predominant channels present and associated syndromes.1–3 AVMs are a subtype of vascular malformations defined as high-flow lesions that involve an anomalous vessel connection at a level larger than capillary.2 These lesions can arise from direct or congenital fistulous connections and are commonly found in the head and neck region, lungs, kidneys, and mesenteric and pelvic circulations.2,4 AVMs often naturally progress and recur after resection, which makes lesion control difficult.5 A vascular anomalies team of specialists is typically required and the standard of care at major referral centers.5 Head and neck AVMs are defined as focal or diffuse, rarely spontaneously regress without treatment and can pose life-threatening challenges due to their infiltrative proximity to vital structures and risk of bleeding.4 Mandibular AVMs are particularly dangerous due to risk of potential spontaneous hemorrhage and complications after tooth extraction.6,7

Destruction of nearby surrounding osseous structures can often occur with craniofacial AVMs.5 According to the article cited by Dr. Strife, almost 50% of AVMs and intraosseous AVMs occur in the head and neck, and pediatric patients make up the majority presenting with mandibular AVMs.6 General indications for AVM treatment include symptoms such as pain, ulceration and hemorrhage, physical deformities interfering with growth and normal activity, and a high-output cardiac state.2 Mandibular AVMs can also be asymptomatic for years or present with swelling, throbbing pain or hemorrhage.5 Dr. Azene’s patient presented with bleeding and dental problems in this case. MRI is typically the gold standard for diagnosis and pre-operative radiographic planning for AVMs, and angiography may be obtained prior to subsequent endovascular intervention.5 The mainstay of temporary control for symptomatic, extensive or otherwise inaccessible mandibular AVMs includes catheter-directed embolization and obliteration of all micro- and macrofistulae through a microcatheter.5 This may be done as primary treatment or pre-operative therapy to reduce the bulk of the resection for more definitive AVM control.5 Embolic and sclerosant agents depend on many factors such as the vascular territory covered, type of abnormality, the possibility of superselective delivery and the occlusive permanence desired.6 Types of agents vary in permanence and may include vascular plugs, coils, tissue adhesives or liquid embolic agents such as the ethanol used in Dr. Azene’s case.6,8 The optimal routes of access to the AVM site may include single or multiple intraosseous direct percutaneous puncture or through transarterial approach.6,9

According to several interventionalists contributing to the discussion on SIR Connect, direct percutaneous puncture into the venous nidus, microcatheter advancement to the site of the AVM and flow control of the external carotid artery provide a safe and efficacious patient outcome in their clinical experience. Several authors such as Drs. Maleson and Strife highlight the utility of scanning the mandible with ultrasound to delineate a route for percutaneous access and the anatomy beneath the thinned cortex of the mandible. One puncture site in the thinnest portion of the bony mandible cortex can allow for safe delivery of sclerosant, filling of the AVM venous lakes and decreased risk of procedural hemorrhage.6 Dr. Strife also discusses alcohol delivery to the venous system fistulous connections and how the theoretical risk of nerve damage due to alcohol in this location is low. Typically, the adverse effects of ethanol embolization include toxicity to intra- and extravascular tissues leading to tissue necrosis.8,10 However, the risk of damage to healthy tissue and vessels may be mitigated with staged therapy in complex lesions, lowering the flow in AVMs to allow for more contact time with sclerosant against the endothelium, precise embolization delivery solely in the AVM nidus and judicious use of less than the total maximum procedural ethanol dose in 1 day (1 ml/kg).8,10 This SIR Connect discussion and future randomized controlled trials may help us further understand the best multidisciplinary approach to managing these lesions as they often warrant long-term follow-up for monitoring of recrudescence and treatment side-effects.  

References:

  1. Enjolras O. Classification and management of the various superficial vascular anomalies: Hemangiomas and vascular malformations.” J Dermatol. 1997;24(11):701–10.
  2. Rosen, et al. Arteriovenous malformations of the viscera and extremities. Handbook of Interventional Radiologic Procedures. 2016:245–257.
  3. Merrow AC, et al. 2014 revised classification of vascular lesions from the International Society for the Study of Vascular Anomalies: Radiologic-pathologic update.” RadioGraphics. 2016;36(5):1494–516.
  4. Rosenberg TL, et al. Arteriovenous malformations of the head and neck. Otolaryngol Clin North Am. 2018;51(1):185–95.
  5. Mulliken JB, et al. Mulliken and Young’s Vascular Anomalies: Hemangiomas and Malformations. 2013.
  6. Wang D, et al. Absolute ethanol embolisation of mandibular arteriovenous malformations following direct percutaneous puncture and release of coils via a microcatheter. Eur J Vasc Endovasc Surg. 2017;53(6):862–69.
  7. Monteiro JLGC, et al. Embolization as the primary treatment for mandibular arteriovenous malformations: An analysis of 50 literature reports and of an illustrative case. J Oral Maxillofac Surg. 2018;76(8):1695–707.
  8. Griauzde J, et al. Endovascular treatment of arteriovenous malformations of the head and neck: Focus on the Yakes classification and outcomes. JVIR. 2020. doi:10.1016/j.jvir.2020.01.036.
  9. Chandra RV, et al. Transarterial embolization of mandibular arteriovenous malformations using ONYX. J Oral Maxillofac Surg. 2014;72(8):1504–10.
  10. Yakes W, Baumgartner I. Interventional treatment of arterio-venous malformations. Gefässchirurgie. 2014;19(4):325–30.

Disclaimer: This column represents the work and opinions of the contributing authors and do not necessarily reflect the views or policies of SIR. SIR assumes no liability, legal, financial or otherwise, for the accuracy of information in this article or the manner in which it is used. The statements made in the column are not intended to set a standard of care and should not to be treated as medical advice nor as a substitute for independent, professional judgment.