Abstract Number ‐ 91: A Case of Complex Giant Neck Arteriovenous Malformation Treated with Endovascular Embolization
Authors: Miller Ethan A , Elmashad Ahmed , Krothapalli Neeharika , Ollenschleger Martin , Mehta Tapan 
Published: April 2023

Introduction
Arteriovenous malformations (AVM) of the head and neck are vascular malformations composed of a cluster of connecting arteries and veins that form a central nidus without an intervening capillary network1. They make up 1.5% of vascular malformations and more than 90% of AVMs are located intracranially1. Extracranial AVMs are predominantly located in the head and neck and can manifest with pain, ulcerations, fatal hemorrhage, airway compromise, and cosmetic aberrations1,2.

Methods
We present a case of a 21 year old female with a medical history of multiple suspected neck hemangiomas status post microsurgical and laser resections, with a surrounding port wine stain, who presented to the hospital with growth of one of her posterior neck hemangiomas during and after pregnancy. In the postpartum period she reported increasing neck pain and persistent bleeding from the site. Initially, she was hemodynamically stable and her neurologic exam did not show any focal deficits. She underwent computed tomography angiogram of her neck which showed an extensive dorsal neck AVM with multiple arterial supplies frombranches of the bilateral subclavian, vertebral, and external carotid arteries.Her lesion continued to bleed with a precipitous drop in hemoglobin requiring blood transfusions. Subsequently, she underwent urgentpercutaneousN‐butyl‐2‐cyanoacrylate (n‐BCA) embolizationand endovascular onyx embolization of a left thyrocervical trunk branch.The procedure was completed without complications. Months later, she developed skin exfoliation and underwent successful elective embolization involving vertebral artery branches. This, to reduce profuse venous shunting in the paravertebral venous plexus, avoiding long term spinal cord injury.

Results
The management of complex head and neck AVMs is both challenging and complex. They may pose significant bleeding risk and can become infiltrative within surrounding tissue3. AVMs may be classified as either focal or diffuse. Focal lesions may be curable with resection, whereas diffuse lesions pose a significant challenge, with relapse in 90% of cases3. Head and neck AVMs require expert management and a multidisciplinary approach. The team may consist of neurosurgery, neuro‐endovascular,plastic surgery, and dermatology services. Treatment options include medical management, surgical resection, endovascular and percutaneous embolization. Percutaenous n‐BCA embolization is employed to prevent hemorrhage during surgical resection, or stabilization in acute hemorrhage4,5. This holds especially true when an endovascular approach is difficult; typically due to tortuous vasculature5. Treatment may require a staged target approach, with endovascular or percutaneous embolization prior to surgical excision.

Conclusions
This case highlights the complexities of AVM management and the multidisciplinary approach necessary, to provide optimal care. In this case, we believe that pregnancy could have contributed to the overall change in aggressive nature of the AVM. The patient underwent emergent percutaneous and endovascular embolization to prevent life threatening hemorrhage followed by palliative embolization to avoid long term cervical spinal cord injury due to venous hypertension.