1.　Embolization of Extracanal/dural Arteriovenous Fistulas

Department of Radiology, Oita University Hospital
Hiro Kiyosue

Abstract
Spinal dural and extradural arteriovenous fistulas (AVFs) are rare spinal/paraspinal vascular lesions that can be roughly divided into two categories of intra-spinal canal lesions and extra-spinal canal lesions. Intracanal lesions include spinal dural AVFs and epidural AVFs. Extracanal lesions consist of various pathologies including several types of paraspinal AVF/ Ms and vertebrovertebral AVFs. All of these lesions can cause serious neurologic symptoms including myelopathy, radiculopathy and spinal or subarachnoid hemorrhage depending on their angioarchitechure. The spinal dural AVF and epidural AVFs with perimedullary drainage frequently cause progressive myelopathy, most of which can be treated by transarterial embolization with NBCA or ONYX. Complete occlusion for the spinal epidural AVFs with paravertebral drainage often requires transvenous embolization with or without transarterial liquid embolization. Early diagnosis and treatment of spinal dural/epidural AVFs is mandatory because clinical outcomes are related to the duration of symptoms. Extracanal lesions can also be treated by endovascular techniques with transarterial and/or transvenous approaches. Precise evaluation of the angioarchitectures and knowledge of spinal vascular anatomy is essential for successful treatment of spinal dural and extradural arteriovenous fistulas.

Key words

• Spinal artery
• Spinal arteriovenous fistula
• Spinal vein

2.　Interventional Radiology for Spinal Arteriovenous Malformations and Fistulae

Department of Radiology, Ohashi Medical Center, Toho University
Yuo Iizuka
Department of Radiology, National Center for Child Health and Development
Yoshiyuki Tsutsumi
Department of Neurosurgery, Seisho Hospital
Yoshifumi Konishi

Abstract
The final outcome of spinal cord vascular malformation (SCVM) is directly related to the prompt diagnosis and treatment of the abnormality. The primary objective of any therapeutic modality should be to obtain a neurologically normal patient, free of future risks in relation to the SCVM. Cure of spinal arteriovenous malformation is seldom obtained without morbidity. In patients in whom a complete cure is not possible at an acceptable level of risk, partial targeted embolization can be proposed with the aims of arresting or improving the clinical situation or modifying the natural history of the disease. Partial targeted embolization will obliterate the weak portion of the angioarchitecture, such as pseudo-aneurysms and varices resulting from previous hemorrhage, reduce the nidus volume, or slow down the flow through the malformation to decongest the venous drainage. These maneuvers improve the venous drainage of the normal spinal cord, often with beneficial effect. Our team’s embolic agent of choice is N-butyl cyanoacrylate (NBCA). Precious deposition of glue in the pathological network will not lead to any neurological deficit, as it will respect the spinal cord. The embryological and functional spinal cord micro vascular anatomy is essential.

Key words

• Spinal arteriovenous malformation
• Embolization
• N-butyl cyanoacrylate

3.　Embolization for Spinal Neoplasms

Department of Radiology and Radiation Oncology, Niigata University School of Medicine
Shoichi Inagawa, Yosuke Horii, Norihiko Yoshimura

Abstract
Embolization for spinal neoplasms is mainly employed preoperatively to reduce adverse blood loss during the surgery, especially total en bloc spondylectomy (TES). We review the frequency of spinal neoplasms, indication and efficacy of TES and preoperative embolization, features of spinal vascular anatomy, technical aspects of embolization, adjuvant embolization for giant cell tumor of spinal vertebrae, and future perspectives based on our experience with these issues to enhance understanding on the side of subscribers. Preoperative embolization is not indicated for all neoplasms in the spinal column but for hypervascular ones as its efficacy was reported mainly with the latter subset of tumors. Features of spinal vascular anatomy are as follow: feeding arteries of the spinal vertebrae are fine in their caliber and directly arise from the aorta; they give rise to arteries feeding the spinal cord; they are connected with each other via abundant collateral anastomoses. Technical aspects of embolization are described in relation to these anatomical characteristics: for example, one should not be content to find that Adamkiewicz artery is not depicted in the arteriography of the target segmental arteries, but should go further to locate which segmental artery gives rise to Adamkiewicz artery.

Key words

• Spinal vertebral neoplasm
• Embolization

4.　Percutaneous Vertebroplasty (PVP) for Vertebral fractures

Department of Radiology, Kansai Medical University, Takii Hospital
Atsushi Komemushi, Satoshi Suzuki, Akira Sano, Koshi Ikeda, Keita Utsunomiya, Yoko Harima
Department of Interventional Radiology, Kansai Medical University, Hirakata Hospital
Shuji Kariya, Miyuki Nakatani, Rie Yoshida, Yumiko Kono
Naoki Kan, Yutaka Ueno, Asami Yoshida, Noboru Tanigawa

Abstract
Percutaneous vertebroplasty is an interventional technique involving a fluoroscopically guided injection of polymethylmethacrylate (PMMA) through a needle inserted into a weakened vertebral body. The technique has been investigated as an option to provide mechanical support and symptomatic relief in patients with osteoporotic vertebral compression fracture or in those with osteolytic lesions of the spine, i.e., multiple myeloma or metastatic malignancies. Multiple obser vational studies have shown almost uniformly excellent results with Percutaneous Vertebroplasty, with moderated to marked pain relief experienced by 75- 95% of patients. Similar results in the treatment of metastatic fractures have also been reported. However, a bias towards overestimation of the treatment benefits is possible when relying on this form of evidence. In 2009, NEJM published the results of the first two randomised blinded trials comparing Percutaneous Vertebroplasty with a sham intervention, namely, local anesthetic infiltration of skin, subcutaneous and periosteum. Both trials reported no statistically significant benefit of Percutaneous Vertebroplasty over placebo. In this article, we will introduce the latest evidence of vertebroplasty.

Key words

• Vertebroplasty
• Vertebral compression fracture
• Pain relief