**8.3 Stereotactic radiosurgery for cAVMs**

High-energy beams of photons or protons to a defined volume containing cAVM nidus are stereotactically focused, and it induces progressive thrombosis of lesions by fibrointimal hyperplasia and subsequent luminal obliteration (**Figure 5**). The time between treatment and obliteration is referred to as the latency period, and it varies from 1 to 3 years. One has to wait for radiosurgery till the hematoma resolves. The factors influencing the obliteration rate of cAVM are cAVM size, target determination, angio-architecture and haemodynamics, cAVM location (hemispheric better) and radiation dosage. Stereotactic radiosurgery for cAVMs has disadvantages of the risk of hemorrhage in latency period and individual variability to radiosensitivity and neurological deficit.

The neurological deficit after radiosurgery is observed in 5.37% of the cases, and it was permanent in 1.46%. The mortality was 1.6%, and it is mainly due to the bleeding in the latency period [24].

The other complications after radiosurgery are radiation necrosis, which causes new neurologic deficits and seizures, and around 8% of the patients develop the parenchymal lesions, cranial nerve deficits, seizures, headaches and cyst formation [25]. The incidence of complications is related to cAVM location and the volume treated. Thalamic, basal ganglionic and brainstem locations are prone to development of deficits after radiosurgery [26]. The risk of complications is also related to


#### **Table 8.**

*Complication of microvascular surgery.*


*(Heros RC, Korusure K, Diebuild PM. Surgical excision if cerebral arteriovenous malformations. Neurosurgery. 1990;***26***:570-577).*

#### **Table 9.**

*Spetzler-Martin grading and patient's outcome after microsurgery* [22, 23]*.*

*Cerebral Arteriovenous Malformation from Classification to the Management DOI: http://dx.doi.org/10.5772/intechopen.86659*

**Figure 5.** *Percentage of cAVM obliteration according to the nidus size (mm) by radiosurgery [25].*

the radiation dose directed to the surrounding tissue and is increased in large brain AVMs that require larger treatment volumes [27]. Repeated radiosurgery is associated with increased complications [28].
