Table 3:

Complications classified according to lesion location, grade, and amount of Onyx injected

AVM S-M GradeLocationAmount of Onyx InjectedComplicationClinicalTreatmentOutcome
3Right frontoparietal3.4 mL 1st SessionIntracerebral hemorrhage due to rupture of a feeding artery while retrieving the microcatheter (Marathon)Immediate deteriorationUrgent craniotomyAVM closed, severe disability
4Right thalamic2 mL 2nd SessionExtravasation of contrast from small feeder due to puncture with guidewireLeft hemiparesthesiaConservativeMostly resolved; left with mild hypoesthesia (good recovery)
4Right frontal7 mL 2nd SessionSmall intracerebral hemorrhage due to extravasation of Onyx from vesselLeft hemiparesisConservativeResolved in 3 months (good recovery)
3Left temporal5.3 mL 1st SessionSubarachnoid hemorrhage due to forced retrieval of catheter from Onyx cast that passed SONIC third markerDysphasiaConservativeMild dysphasia resolved within 6 months (good recovery)
4Left parietal2 mL 3rd SessionSmall intracerebral hemorrhage 2 days after treatment, most probably due to venous occlusionNo new deficitConservative(Good recovery)
3Right parietal6.7 mL 1st SessionSmall intracerebral hemorrhage due to venous congestion, after complete occlusion in 1 session (Fig 3)Left proprioception deficitConservativeResolved in 2 weeks, complete occlusion on angio follow-up (good recovery)
3Left fronto-opercular4 mL 1st SessionIntracerebral hemorrhage due to venous congestion, after complete occlusion in 1 sessionSeizure and right hemiparesisUrgent craniotomy for hematoma evacuationMild short memory deficit (good recovery)