Complications classified according to lesion location, grade, and amount of Onyx injected
| AVM S-M Grade | Location | Amount of Onyx Injected | Complication | Clinical | Treatment | Outcome |
|---|---|---|---|---|---|---|
| 3 | Right frontoparietal | 3.4 mL 1st Session | Intracerebral hemorrhage due to rupture of a feeding artery while retrieving the microcatheter (Marathon) | Immediate deterioration | Urgent craniotomy | AVM closed, severe disability |
| 4 | Right thalamic | 2 mL 2nd Session | Extravasation of contrast from small feeder due to puncture with guidewire | Left hemiparesthesia | Conservative | Mostly resolved; left with mild hypoesthesia (good recovery) |
| 4 | Right frontal | 7 mL 2nd Session | Small intracerebral hemorrhage due to extravasation of Onyx from vessel | Left hemiparesis | Conservative | Resolved in 3 months (good recovery) |
| 3 | Left temporal | 5.3 mL 1st Session | Subarachnoid hemorrhage due to forced retrieval of catheter from Onyx cast that passed SONIC third marker | Dysphasia | Conservative | Mild dysphasia resolved within 6 months (good recovery) |
| 4 | Left parietal | 2 mL 3rd Session | Small intracerebral hemorrhage 2 days after treatment, most probably due to venous occlusion | No new deficit | Conservative | (Good recovery) |
| 3 | Right parietal | 6.7 mL 1st Session | Small intracerebral hemorrhage due to venous congestion, after complete occlusion in 1 session (Fig 3) | Left proprioception deficit | Conservative | Resolved in 2 weeks, complete occlusion on angio follow-up (good recovery) |
| 3 | Left fronto-opercular | 4 mL 1st Session | Intracerebral hemorrhage due to venous congestion, after complete occlusion in 1 session | Seizure and right hemiparesis | Urgent craniotomy for hematoma evacuation | Mild short memory deficit (good recovery) |