Update Onyx embolization for plexiform arteriovenous malformation: Ante-grade drifting technique

Abstract

Objective: The conventional arteriovenous malformation (AVM) Onyx embolization technique is the extrusion Onyx injection technique, with blood-flow control after a certain distance casting through the head end of the microcatheter. This method has elevated periprocedural AVM bleeding complications. In this study, the authors reported safety and efficacy of an updated ante-grade drifting Onyx injection for plexiform AVM embolization.

Methods: Between January 2016 and December 2018, 101 consecutive patients with plexiform AVMs were treated with ante-grade drifting Onyx injection. The patients' clinical status was classified using the modified Rankin Scale (mRS). To measure associations, logistic univariate or multivariate regression analyses were used.

Results: Complete AVM obliteration was achieved in 51.2% (52/101) of patients. Two (2/101, 2.0%) arterial perforations occurred without causing neurological deficits. In univariate and multivariate logistic regression analyses, younger patient age (odds ratio (OR) = 1.06, 95% confidence interval (CI) 1.01-1.12, p = 0.014), haemorrhagic presentation at admission (OR = 7.14, 95% CI 1.52-33.33, p = 0.013) and low Spetzler-Martin grade (OR = 10.00, 95% CI 3.45-25.00, p < 0.001) were significantly correlated with complete obliteration. Pretreatment mRS was correlated with perforation complication (OR = 3.44, 95% CI 1.05-11.29, p = 0.041) in univariate logistic regression analysis but not in multivariate logistic regression analysis (OR = 2.956, 95%CI 0.745, 11.731, p = 0.123). Patients' clinical status was significantly improved after endovascular AVM embolization.

Conclusions: With ante-grade drifting Onyx injection, it was possible to prevent serious bleeding complications and elevated complete embolization rate in plexiform AVMs. Younger patient age, haemorrhagic presentation at admission and low AVM Spetzler-Martin grade were significantly correlated with complete obliteration. Although there is not enough statistical power to show that the pretreatment mRS and the arterial perforation complication have a significant correlation, but its OR value is large, and there may be more data in the future to obtain further conclusion.

Keywords: Arteriovenous malformation; embolization; plexiform; technique.

Figure 1.

Unsubtracted angiogram of the right vertebral artery, lateral view, showing a thalamus arteriovenous malformation (AVM) and intra-nidal penetrating Onyx cast, which was injected using ante-grade drifting technique via the right posterior lateral choroidal artery without any reflux (arrow).

Figure 2.

A 25-year-old man with a ruptured AVM in the right temporal lobe. (a) Right vertebral artery injection, frontal view, showing a grade I AVM fed by temporal branches of right posterior cerebral artery (arrowhead). (b) Super-selective injection after one branch catheterization (arrowhead). (c) Super-selective injection of the second branch catheterization (arrowhead). (d) Unsubtracted image of working angle showing the intra-nidal Onyx cast (arrowheads). (e) Left vertebral artery injection after two branches ante-grade drifting Onyx injection, frontal view, showing complete occlusion of the nidus.

Figure 3.

A 33-year-old man presented with an intracranial haematoma. (a) Left internal carotid artery injection, lateral view, showing a grade II AVM fed by branches of the left anterior and middle cerebral arteries and had a venous aneurysm on the draining vein, which was rupture site (arrowhead). (b) Super-selective injection after the anterior cerebral artery feeding branch catheterization (arrowhead). (c) Super-selective injection after the middle cerebral artery feeding branch catheterization (arrowhead). (d) Left internal carotid artery injection after embolization, lateral view, showing complete embolization of the AVM (arrowheads).