Surgical and Endovascular Treatment for Spinal Arteriovenous Malformations

Abstract

Spinal arteriovenous malformation (AVM) is a broad term that constitutes diverse vascular pathologies. To date, various classification schemes for spinal AVM have been proposed in literature, which helped neurosurgeons understand the pathophysiology of the disease and determine an optimal treatment strategy. To discuss indications and results of surgical and endovascular interventions for spinal AVM, this article refers to the following classification proposed by Anson and Spetzler in 1992: type I, dural arteriovenous fistula (AVF); type II, glomus intramedullary AVM; type III, juvenile malformations; and type IV, perimedullary AVF. In general, complete obliteration of the fistula is a key for better outcome in type I dural and type IV perimedullary AVFs. On the other hand, in type II glomus and type III juvenile malformations, functional preservation, instead of pursuing angiographical cure, is the main goal of the treatment. In such cases, reduction of the shunt flow can alleviate clinical symptoms. Proper management of spinal AVM should start with neurological examination and understanding of angioarchitectures, which provide critical information that guides the indication and modality of intervention. Finally, close collaboration of the microsurgical and endovascular teams are mandatory for successful treatment.

Fig. 1.

A representative case of mid-thoracic type I spinal dural arteriovenous fistula. A 65-year-old man presenting with lower extremities weakness and sensory disturbance below T11 dermatome. A: T₂-weighted sagittal magnetic resonance image demonstrating abnormal flow voids dorsal to the spinal cord (arrowheads) below T8 vertebral level. B: A selective angiogram of the right T9 segmental artery demonstrating spinal DAVF (white arrow) fed by the radiculomeningeal artery. Perimedullary draining vein pierced the dura at the right T9 dural root sleeve (black arrow). C: Three-dimensional fusion image of rotational angiography and computed tomography of the thoracic spine. Dorsal view indicated the point where the draining vein entered intradurally (black arrow). D–G: Intraoperative images (D, F) coupled with images from indocyanine green videoangiography (E, G). Right T9 partial hemilaminectomy and dural incision identified the point where the draining vein entered intradurally (arrows in D and E). After the draining vein was cut (F), abnormal blood flow in the arterialized vein disappeared (G). Note, T9 dorsal nerve root was preserved (arrowheads in F). H: Three-dimensional reconstruction of computed tomography, a dorsal view of the thoracic spine, showing area of the bone window on the right T9 lamina. Postoperative course was uneventful. Patient’s symptoms remarkably improved after the operation. Rt.: right.

Fig. 2.

A representative case of extradural spinal arteriovenous fistula (AVF) successfully treated by sole intradural drainer occlusion. A 59-year-old man presenting with progressive pain and weakness in the lower extremities as well as urinary retention. A: Preoperative sagittal T₂-weighted magnetic resonance (MR) image reveals intramedullary hyperintensity of the thoracolumbar spinal cord. B: Preoperative MR angiograpm reveals an epidural venous lake located outside the spinal canal (arrow). C, D: Time course images of the preoperative selective angiograms of the left L1 segmental artery. AVFs (black arrowheads in C), an epidural venous lake (asterisks), a draining vein (white arrowheads in D), and dilated spinal veins (white arrow in D) are visualized. Black arrow in D indicates the entry points of the draining vein crossing the dura. E, F: Intraoperative photographs coupled with images from indocyanine green (ICG) video angiography. The dura matter is indicated by black arrows. A draining vein penetrating the dura matter (arrowheads) and a dilated spinal vein (white arrows) were observed after hemilaminectomy of T12. ICG video angiography clearly identified the penetration site at the dorsolateral wall of the dural sac. The draining vein was coagulated and resected intradurally. G, H: Postoperative MR images 6 months after surgery. Sagittal T₂-weighted image (G) shows a decreased hyperintensity signal. MR angiogram reveals obliteration of the epidural venous lake, and the draining vein has disappeared. Figures were obtained and modified with permission from the following reference and rearranged: Niizuma et al., 2013.

Fig. 3.

A case of thoracic juvenile malformations treated by transarterial embolizations followed by open surgery. A, B: Preoperative selective angiograms through right T5 intercostal (A) and left descending scapular (B) arteries demonstrating arteriovenous fistulas along the left T5 root sleeve (arrows). An enlarged epidural venous plexus was apparent. C, D. Selective angiogram after endovascular interventions. Arteriovenous shunts and enlarged venous structures were not evident through selective angiography of the right T5 intercostal (C) and left descending scapular (D) arteries. E, F. Preoperative (E) and postoperative (F) axial T₂-weighted magnetic resonance images of the thoracic spinal cord. Note, engorged vein compressing the spinal cord (arrowheads in E) disappeared after the endovascular interventions (F). Open surgery followed the endovascular treatments and eliminated residual shunt flow. Figures were obtained and modified with permission from the following reference and rearranged: Elkordy et al. 2015.

Fig. 4.

A case of craniocervical junction type IVb perimedullary arterioveous fistula (AVF) presented with subarachnoid hemorrhage. A: Three-dimensional reconstruction image of the left vertebral artery rotational angiogram (posterior view) demonstrating perimedullary AVF (asterisk) fed by the anterior spinal (white arrowheads), C2 radiculomedullary (white arrow), and C1 radiculopial (black arrow) arteries. B: Open surgery was performed with suboccipital craniectomy and C1 hemilaminectomy (note, the rostral side of the patient is displayed at the bottom of the picture). A radiculopial artery was identified as one of the feeding arteries (black arrow). C, D: Ventrally located AVFs were successfully managed with endoscopic assistance. The anterior spinal (white arrowheads in C) and C2 radiculomedullary (white arrows in D) arteries were clearly visualized in endoscopic views. Figures were obtained and modified with permission from the following reference and rearranged: Endo et al. 2014.