Article
Factors influencing the obliteration rate of cerebral arteriovenous malformations after Gamma-Knife radiosurgery
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Published: | April 28, 2011 |
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Objective: To determine the influence of several factors on the chance of obliteration after Gamma-Knife-radiosurgery for cerebral arteriovenous malformations (cAVM).
Methods: Angiographic follow-up (FU) was available for 101 of 162 cAVM in 156 Patients (72 female, 84 male; mean age 35.3 years, range 3-78) that were treated with Gamma-Knife radiosurgery between July 1998 and July 2005 (mean FU-time 37.3 months, range 15-101). 5 of those were re-treatments. Complete clinical FU-information was obtainable for 136 patients. 54 angiomas (33.3%) were previously embolized at least once. Main presenting symptoms were previous hemorrhage (46.9%), seizures (27.7%), sensorimotor deficits (24.7%) and headache (11.1%). Mean volume before treatment was 3.69 cm3 (0.021-12.9 cm3), the Spetzler-Martin-Grades ranged from 1 to 4. The parameters analyzed were previous embolization, patient age and gender, nidus volume and maximum diameter, minimum and maximum dose, previous hemorrhage and the Spetzler-Martin grade.
Results: The angiographically confirmed overall obliteration rate was 72.3%. For patients with previous embolization, it was statistically significant lower than for those without (54.3% vs. 81.8%, p=0.005). Small lesions obliterated more often than mid-sized lesions (77.6% vs. 56.0%, individual p=0.043), but after Bonferroni correction for multiple testing, this was not significant. All other factors had no statistically significant influence. During the latency period, 9 hemorrhages occurred in 8 cAVM (mean time 16.1, range 6-36 months after treatment) resulting in an overall bleeding rate of 6.4% (no permanent morbidity, no mortality). Permanent new neurological deficits occurred in 2 patients (1.5%).
Conclusions: Gamma-Knife radiosurgery is a safe treatment method for cAVM that led to angiographically confirmed obliteration in 72.3% of the study population. Due to its statistically firm negative influence on the probability of obliteration, the indications for pre-radiosurgical embolization should be reconsidered.