Incidental occlusion of right vertebral artery due to Onyx reflux in embolization of vertebral arteriovenous fistula in pediatric patient

CASE PRESENTATION 

A 13-year-old boy was admitted to the emergency room  with a 1-week history of progressive weakness and paresthesias in his upper and lower extremities. There was subarachnoid hemorrhage in anamnesis.  Neurological  examination revealed motor deficit in all extremities: 3/5 right arm, 3/5 left arm, 4/5 right leg, 4/5 left leg.  Digital subtractial angiography  was performed and the result suggested a spinal AV fistula. 

• The angiogram demonstrated a spinal AV fistula with one feeder - the right VA. The nidus of the AVM and congested medullary draining veins were also observed. Endovascular embolization was performed under general anesthesia after heparinization (2000 IU).
• Endovascular treatment was performed with this patient under general anesthesia. 6F catheter was positioned in the vertebral artery and microcatheter Rebar was advanced in a dural feeding artery close to the fistula site

• Afterward, Onyx 20 was slowly injected. We were waiting the reflux and when it occurred, we paused the injection for 2 minutes. We occurred the reflux 5 times before Onyx would advance into the fistula site. Once Onyx glue advanced, it was injected until the draining veins were filled and feeder artery were filled retrograde, thereby completely occluding the fistula. 

• Successful embolization of the nidus supplied from the feeder  with Onyx 2.0ml.  Total occlusion of fistula was achieved

During the removing a rebar microcatheter a small amount(max. Sizes 0,7x0,4cm) of Onyx occluded the vertebral artery. A control angiogram demonstrated occlusion of the vertebral artery

• We aimed to remove the Onyx embolus from the vertebral artery by using a 4x20mm Solitaire retriever. Under fluoroscopic guidance , the Solitaire retriever was deployed within the partially occluded artery

• After waiting 2 minutes, fully opened Solitaire was pulled back into the guiding catheter. The guiding catheter with Solitaire retriever was taken out and the stent inspected. The Onyx embolus was completely removed from the vertebral artery

• The controlled angiography showed full preservation of right vertebral artery

• The patient remained in the intensive care unit (ICU) for one day after the procedure, then he was transferred to neurosurgery department for 4 days and discharged from hospital without any neurological deficit.

DISCLOSURE

• Spinal AV fistula  is a rare lesion that causes neurological morbidity as a result of hemorrhage and/or venous hypertension, arterial steal, or mass effect.  Spinal vascular malformations have been treated surgically and by endovascular embolization. Endovascular treatment is preferred for most of these complex vascular malformations because of the high degree of morbidity associated with surgery.
• In our own case, we preferred  to occlude AVF  endovasculary, it was successfully occluded, however incidental artery occlusion happened. We removed Onyx glue embolus by retriever and fully  recanalisation was achieved.  

REFERENCES

• 1. Spinal Dural Arteriovenous Fistulas     T. Krings and S. Geibprasert        American Journal of Neuroradiology April 2009, 30 (4) 639-648;
• 2.Incidental occlusion of anterior spinal artery due to Onyx reflux in embolization of spinal type II arteriovenous malformation
• Joohyun Kim, Jang-Bo Lee, Tai-Hyoung Cho & Junseok W. Hur;
• Onyx Liquid Embolic System, Medtronic.
• https://europe.medtronic.com/xd-en/healthcare-professionals/products/cardiovascular/peripheral-embolization/onyx.html