Strategies on the treatment of intracranial arteriovenous malformations

Abstract

Surgical treatment of intracranial arteriovenous malformation (AVM) is one of the most difficult tasks for neurosurgeons, especially, for patients with large size AVM or AVM at the eloquent and deep location. Recent advent of endovascular treatment and radiosurgery may replace the role of surgery and decrease the difficulty of treatment of AVM to some extend but not all. Surgical excision with or without preoperative embolization remains the main modality of treatment of intracranial AVMs. However, the procedure of embolization itself also carries certain percentage of risk. Selection of this treatment modality needs to be carefully evluated.For small deep seated AVM and small AVM at the eloquent area, radiosurgery is another therapeutic option. However, the efficacy to achieve obliteration of the AVM by radiosurgery is only 60%-70% in general. Combined embolization and radiosurgery has been advocated as an option for treating large complex AVM. However, current treatment results failed to demonstrate any superiority of the result from this combined treatment.Palliative treatment with partial obliteration of the AVM nidus toreduce arteriovenous shunting is considered to be useful for the decrease of the occurrence of steal phenomenon, however, it may also increase shear stress of the abnormal vascular architecture and resulted in increase rate of hemorrhage.From 1989 to 2011, a total of 367 patients with cerebral AVM were treated at the National Taiwan University Hospital and its’ affiliate hospitals. Of these 367 patients, 143 patients underwent microsurgery as the solo treatment and 214 patients received embolization. In the later group, 25 patients had their AVMs cured after one or multiple sessions of endovascular treatment. The other 189 patients in this group, endovascular treatment can only be applied for the reduction of the flow and the size of the AVM. These patients finally underwent microsurgery as the definite treatment. The treatment morbidity was 11% in microsurgical group and 9% inendovascular group. There were 2 mortalities in surgical group (o.6 %) and 2 in endovascular group (0.9 %).Our current selection criteria for different therapeutic modality and surgical strategy for intracranial AVM will be discussed. Surgical treatment of intracranial arteriovenous malformation (AVM) is one of the most difficult tasks for neurosurgeons, especially, for patients with large size AVM or AVM at the eloquent and deep location. Recent advent of endovascular treatment and radiosurgery may replace the role of surgery and decrease the difficulty of treatment of AVM to some extend but not all. Surgical excision with or without preoperative embolization remains the main modality of treatment of intracranial AVMs. However, the procedure of embolization itself also carries certain percentage of risk. Selection of this treatment modality needs to be carefully evluated. For small deep seated AVM and small AVM at the eloquent area, radiosurgery is another therapeutic option. However, the efficacy to achieve obliteration of the AVM by radiosurgery is only 60%-70% in general. Combined embolization and radiosurgery has been advocated as an option for treating large complex AVM. However, current treatment results failed to demonstrate any superiority of the result from this combined treatment. Palliative treatment with partial obliteration of the AVM nidus toreduce arteriovenous shunting is considered to be useful for the decrease of the occurrence of steal phenomenon, however, it may also increase shear stress of the abnormal vascular architecture and resulted in increase rate of hemorrhage. From 1989 to 2011, a total of 367 patients with cerebral AVM were treated at the National Taiwan University Hospital and its’ affiliate hospitals. Of these 367 patients, 143 patients underwent microsurgery as the solo treatment and 214 patients received embolization. In the later group, 25 patients had their AVMs cured after one or multiple sessions of endovascular treatment. The other 189 patients in this group, endovascular treatment can only be applied for the reduction of the flow and the size of the AVM. These patients finally underwent microsurgery as the definite treatment. The treatment morbidity was 11% in microsurgical group and 9% inendovascular group. There were 2 mortalities in surgical group (o.6 %) and 2 in endovascular group (0.9 %). Our current selection criteria for different therapeutic modality and surgical strategy for intracranial AVM will be discussed.