| Gamma Knife Radiosurgery for Infratentorial Arteriovenous Malformations |
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Seung Hwan Lee, Young Jin Lim, Jun Seok Koh, Tae Sung Kim, Bong Arm Rhee, Gook Ki Kim |
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Department of Neurosurgery, School of Medicine, Kyung Hee University, Seoul, Korea |
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| Abstract |
Objective
Infratentorial arteriovenous malformation is rare disease. Because their lesions are adjacent critical sturucture, noninvasive radiosurgeries are popularly in use as a primary treatment. However, the treatment method is known for its difficulty in giving
sufficient dose of radiation due to adjacent critical structures. It also has been reported to show unfavorable prognosis when the
rebleeding occurs. This study analyzes the treatment results of the patients who had been treated with Gamma Knife Radiosurgery for infratentorial arteriovenous malformation in our gamma knife center.
Materials and Methods: Forty-five patients with infratentorial AVMs underwent gamma knife radiosurgery between June 1992
and December 2004. Presenting symptom, angiographic architecture and radiosurgical plan of these AVMs were evaluated. The group
consisted of 29 male and 16 female patients. Mean age was 31.9 (range 5-61). Mean follow-up period of was 34.2 months
(range 6-138 months).
Results
Anatomical locations of these AVMs included deep cerebellum (20 lesions), thalamopeduncular area (11 lesions), tectopineal area (9 lesions), and midbrain (5 lesions). Thirty-one patients (68.9%) presented with hemorrhage, 9 patients (20.0%)
with headache, 2 patients (4.4%) with seizure, 2 patients (4.4%) with dizziness, and 1 patients (2.3%) with ptosis. Spetzler-Martin Grade was II in 15 patients (33.3%), III in 23 patients (51.1%), IV in 5 patients (11.1%), and V in 2 patients (4.5%). In the analysis of GKRS treatment plans, mean volume was 2645.6mm3
(range 105-25308mm3
) and mean maximal dose was 38.6Gy (range
28.6-60Gy), Marginal dose was 23.1Gy (range 15-24Gy) and Mean isocenter were 2.85 (range 1-9). Upon subsequent followups after the surgery, complete obliteration rate was 7.5% after 1 year, 52.5% after 2 years and 72.5% after 3 years. Rebleeding was
occurred in 2 cases (4.4%) after 44 months and 118 months after surgery respectively；in one of which case the patient died. Adverse
radiation effect was found in 3 cases (6.7%).
Conclusion
In this study, gamma knife radiosurgery for Infratentorial arteriovenous malformation showed lower complete obliteration
rate and more frequent complication occurrence after surgery compared to the treatment for other lesions. Application of standard
radiosurgical dose with sophisticated treatment planning can improve radiosurgical outcome for infratentorial AVMs. |
| Key Words:
Radiosugery, AVM, Infratentorium. |
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