Retrograde venonidal microsurgical obliteration of brain stem AVM: a clinical feasibility study

The highly eloquent surroundings of brainstem arteriovenous malformations (AVMs) present particular surgical challenges. In the present pilot study we tried to examine whether to occlude the draining vein after control of major feeding arteries and then to coagulate the nidus retrogradely might be a viable concept for brainstem AVMs instead of the traditional perinidal dissection.

A total of five patients harbouring pontine or mesencephalic AVMs were treated at our institution between February 2007 and August 2008. Three of them presented after haemorrhage. In two instances, partial endovascular obliteration was performed prior to surgery. Following exposure and control of major feeders, the principal draining vein was clamped to test tolerance. In none of the cases was major stasis and bleeding from the nidus seen. The draining vein was subsequently coagulated and then stepwise shrinking by retrograde coagulation of the nidus was done. The coagulated nidus was left in place.

The procedure was technically successful in all cases and no major postoperative complication related to the procedure was seen. Control angiography confirmed complete occlusion in all cases.

Due to the usually small size of brainstem AVMs, retrograde coagulation of the nidus without additional resection can be a feasible approach in order to avoid additional damage by circumferential dissection.