|Year : 2014 | Volume
| Issue : 6 | Page : 263-266
Treat high cervical spinal arteriovenous malformation with Cyberknife radiosurgery
Yu-Fen Huang1, Chun-Ming Yen1, Chiung-Chyi Shen2, Jia-Wei Lin3, Wen-Yu Cheng4
1 Department of Neurosurgery, Taichung Veterans General Hospital, Taiwan, Republic of China
2 Department of Neurosurgery, Taichung Veterans General Hospital; Faculty of Medicine, School of Medicine, National Yang-Ming University, Taiwan, Republic of China
3 Department of Neurosurgery, CyberKnife Center, Wang Fang Hospital, Taiwan, Republic of China
4 Department of Neurosurgery, Taichung Veterans General Hospital; Institute of Molecular biology, National Chung Hsing University; Department of Physical Therapy, Hung Kuang University, Taichung, Taiwan, Republic of China
|Date of Submission||16-Jun-2014|
|Date of Decision||09-Jul-2014|
|Date of Acceptance||25-Jul-2014|
|Date of Web Publication||19-Dec-2014|
Dr. Wen-Yu Cheng
Department of Neurosurgery, Taichung Veterans General Hospital, #1650, Taiwan Boulevard, Section 4, Taichung 40705, Taiwan
Republic of China
Source of Support: None, Conflict of Interest: None
This paper describes the use of CyberKnife radiosurgery in the treatment of accidentally found cervical spinal arteriovenous malformation (AVM). We present the case of a patient with cervical spinal AVM, who developed progressive neck pain, gait disturbance, urine and stool incontinence 2 weeks after the fell down accident. The patient underwent CyberKnife radiosurgery. After CyberKnife radiosurgery for 2 years, the patient's neck pain diminished and was able to keep the walk without any assistance. The management of cervical spinal AVM varies. This patient demonstrated a successful treatment of cervical spinal AVM with CyberKnife radiosurgery.
Keywords: CyberKnife, spinal arteriovenous malformation, stereotactic radiosurgery
|How to cite this article:|
Huang YF, Yen CM, Shen CC, Lin JW, Cheng WY. Treat high cervical spinal arteriovenous malformation with Cyberknife radiosurgery. J Med Sci 2014;34:263-6
|How to cite this URL:|
Huang YF, Yen CM, Shen CC, Lin JW, Cheng WY. Treat high cervical spinal arteriovenous malformation with Cyberknife radiosurgery. J Med Sci [serial online] 2014 [cited 2019 Oct 22];34:263-6. Available from: http://www.jmedscindmc.com/text.asp?2014/34/6/263/147253
| Introduction|| |
Spinal arteriovenous malformation (AVM) is an uncommon entity which compromise about 4% of primary intraspinal masses. The treatments of spinal AVM in the past included microsurgical resection, embolization, or both. However, some cases cannot be managed with conventional manners by virtue of AVM size, eloquent location or complex angioarchitecture. We presented our successful case treated by CyberKnife radiosurgery who was a 66-year-old male patient whose spinal AVM along the foramen magna and upper cervical spine regarding as high-risk lesion whether surgery or embolization.
| Case Report|| |
The 66-year-old man is a Taiwanese, who had no systemic disease before. He fell down from the tree 1 month ago prior to admission, there is not any neurological deficit on that movement. Unfortunately, he felt progressive neck pain while extension and gait disturbance 2 weeks later, urine and stool incontinence ensued. Neurological examination revealed: Positive Hoffman sign, positive Babinski sign, absent of babocavernous reflex. Numbness sensation below T1 dermatone. Bilateral legs muscle power grade 2. Under the impression of cervical spine injury, cervical spine magnetic resonance imaging (MRI) was arranged. Surprisingly, worm-like appearance of flow void signal intensity markedly noted at C1-2 level of the dural sac and extending into C7 level. Besides, hyper-intensity signal of C3-T2 level of spinal cord in T2-weighted image, and hypo- to isointense in T1-weighted image also noted [Figure 1]. For more information, computed tomography angiography (CTA) was also arranged [Figure 2]. Type I spinal AVM with secondary cord ischemia was diagnosed. After detailed evaluation, surgery and endovascular embolization were suggested, but the patient refused. He wish noninvasive treatment. Therefore, he underwent CyberKnife stereotactic radiosurgery (SRS) in August, 2007. Three-dimensional CTA scanning was acquired which registered using a normalized mutual information algorithm. The patient was positioned supine in a standard vacuum conformed immobilization device. A dose of 22 Gy was prescribed to the 56% isodose and delivered in three fractions on the nidus at C1 level, and 18 Gy was prescribed to the 60% isodose and delivered in two fractions on the nidus at C2 level. Skull 6D tracking mode and a 7.5 mm collimator were used. Our treatment details were listed [Table 1] and delivery depicted [Figure 3] and [Figure 4].
|Figure 1: T2-weighted MR image showed flow void signal lesion at C1-2 and extending to C7, hyperintensity signal also noted from C3 to T2. Axial view showed engorged vessel mainly in the dural sac|
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|Figure 2: CT angiography of the neck with IV contrast. Engorged vascular structure in the spinal canal along the foramen magna and upper C-spine. The white arrow point out feeding artery from the right vertebral artery at C1-2 level from medially through the right neuroforamen of C1-2 into the spinal canal|
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|Figure 3: Screenshot of a treatment plan for a C1 Type I spinal arteriovenous malformation treated with 22 Gy delivered in 3 sessions|
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|Figure 4: Screenshot of a treatment plan for a C2 Type I spinal arteriovenous malformation treated with 18 Gy delivered in 2 sessions|
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He tolerated the treatment well, and his symptoms did not progress. According to the acute radiation morbidity scoring system, the patient's condition was classified as grade 2 due to the need of steroid treatment. Follow-up MRI at our clinic was performed at 3, 8, 12 and 24 months posttreatment. Improvement of neurological symptoms was apparent during the 2 years. He can walk without any assistance. His bilateral legs muscle power recovered to grade 4. Numbness sensation persisted, but only restricted on bilateral legs and sacrum region. Additionally, the patient still had urine incontinence and need intermittent catheterization by himself.
Posttreatment MRI was repeated at 3, 8, 12 and 24 months and showed a gradual reduction of AVM volume. In addition, vascularity of the AVM also significantly decreased as determined by the size and number of flow voids [Figure 4]. Throughout the follow-up period, there is no bleeding episode or chronic radiation-related toxicity.
| Discussion|| |
The term spinal AVMs, which technically refers to a subset of spinal vascular malformations. They are categorized into four groups:  Type I: Dural AVM, also known as dural AV fistula (AVF). Type II: Intramedullary glomus-type AVM. Type III: Juvenile-type intra + extramedullary AVM. And Type IV: Direct extramedullary AVF.
The type shown in our case is Type I, that is, dural AVM. This is the most-common type (80%) of spinal AVM.  They usually occur in patients older than 40-year-old. Males (80-90%) are more common than females. Site of pathology in these lesions is within the dural root sleeve. Venous drainage of the AVF is by a high-pressure, low-flow arterialized vein intradurally. Symptoms arise because the AVF causes venous congestion and hypertension, resulting in poor perfusion of the spinal cord. Cord involvement may be distant to the fistula. Hence, we can find hyperintensity signal at C3-T2 cord in T2-weighted-image in our patient which is distant to the C1-2 nidus.
The goal of treatment is isolation and obliteration of the fistula and draining veins, which normalizes venous pressure and corrects venous hypertension. In the tradition, two different therapeutic modalities are adopted: Embolization of the feeding vessel via endovascular techniques and direct surgical ligation. In this case, the site of AVF is mostly in the ventral part of high cervical spine, direct surgical exposure is dangerous. Our patient's lesion located in an extremely eloquent area of central nervous system and its location made surgical approach is difficult, microsurgical ablation present high-risk complications. Type I spinal AVM is usually amenable to endovascular techniques using glue, nevertheless if dural fistula cannot completely eliminate it will come back. Spinal angiography is the gold standard exam for the diagnosis and therapeutic planning, but the patient feared this exam. We gave up spinal angiography and embolization due to patient's desire and complex angioarchitecture of AVM by MRI, which was believed difficult for an endovascular treatment. MRI are useful in the screening to locate the lesion (demonstrating its relation with the spinal cord and the meningeal spaces) and to show evidence of bleeding, swelling, atrophy, venous thrombosis, or intramedullary cavities. , On the conclusion of multidisciplinary discussion, we took a neoteric treatment, that is, radiosurgery into consideration [Figure 5].
|Figure 5: (a~d) posttreatment 3, 8, 12, 24 months magnetic resonance imaging (MRI) follow-up showed a gradual reduction of the size of arteriovenous malformation (AVM) and significant decreased vascularity. (e). Axial view of MRI showed nearly disappearance of AVM in the dural sac|
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CyberKnife SRS has used to treat selected spinal cord AVMs since 1997, preliminary result demonstrates its feasibility and apparent safety for selected intramedullary spinal cord AVMs.  We extended its utilization for dural AVM to our case. The underlying mechanism of action for radiosurgery is thought to be gradual endothelial hyperplasia of the abnormal vasculature, which in turn, leads to progressive narrowing and eventual vessel occlusion.  When smaller than 2.5 cm in diameter, subsequent obliteration occurs in 80-85% of AVMs over a 2-3 years period. , The major drawback to radiosurgery is that, until the AVM is obliterated (the latency period), patients remain at risk for hemorrhage. , In this case, CyberKnife SRS reduced successfully the volume and vascularity of AVM and significantly improved neurological function. On regular follow-up MRI, we also found gradually subsided hyperintensity signal of C3-T2 cord and believed that venous hypertension relieved after radiosurgery. We are also privileged that patient have hemorrhage-free follow-up period.
| Conclusion|| |
Although this is our first experience of CyberKnife radiosurgical ablation of spinal AVM, excellent outcome is detected whether in clinical symptoms or radiological manifestation. Patients who are unsuitable for conventional therapies, or when conventional therapies are refused, the CyberKnife system provided delivery of noninvasive, painless, and efficacious treatment which results in hemorrhage-free and radiation-free injury during the follow-up period.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]