Introduction: Parieto Occipital Avms are not easy to be classified because there is no such separating sulcus on the lateral hemisphere. The sylvian fissure divides these two lobes arbitrarily. Due to their complex vascular architecture and the intimate relationship of the optic radiationand visual cortex , as well as proximity to motor cortex, parieto occipital lobe AVMs are surgically challenging.

Methods: 15 parieto occipital lobe AVMs were retrospectivelly studied regarding to their historical records, image findings, surgical records and outcome. A avarage age of 34 year old, and 8 female and 7 male patients, were operated from 2000 to 2015 , all of them classified as Spetzler II (10 cases), Spetzler I (3 cases), Spetzler III (2 cases). The main symptom :hemorrhage in 7 patients, visual epileptic crisis in 3 cases, headache in 3 cases and progressive deficit in 2 cases. Five were previously submited a series of endovascular treatment and 1 radiosurgery before bleeding.

Results: All cases were submitted to a large parieto occipital craniotomy, in the last 3 cases the craniotomy was marked guided by neuronavigation. The evoked potential was used to identify the motor area, as well as cortical stimulation was alo used. The geniculo calcarine artery and parieto occipital artery was the main feeding, and the first vessels to be occluded during the parallel and vertical dissection. Transient visual impairment was observed in 3 patients, permanent in 2 patients, transient motor deficit in one patient. No mortality was observed.

Conclusions: The large craniotomy for the parieto occipital AVms may be useful in order to identify the anatomical landmarks, and to facilitate the conic dissection and oclusion of feedings. We must keep in mind that the main arteries are the geniculo calcarin and parieto occipital arteries, and we can have branches innerly from posterior choroidal arteries.

Patient Care: to make better the plan to resect the parieto occipital AVM

Learning Objectives: 1-Sistematic organization to accomplish total removal of parieto occipital lobes AVMs

References: Yasargil MG. Special surgical considerations. In Yasargil(ed): Microneurosurgery. Vol IIIB, AVM of the brain, clinical considerations, general and special operative techniques, surgical results, nonoperative cases, neuroanesthesia. Stuttgart,George Thieme Verlag, 1988, 56-58, 164-167. Wanebo JE, Ojeman JG, Dacey RG. Supratentorial lobar arteriovenous malformations. In: Stieg P, Batjer HH, Samsom D. Intracranial Malformations. Informa Healthcare, 2007, new York, Chapter 16, pp 215-241 Lawton MT. Parieto occipital malformations. In Lawton M (ed): Seven AVMs, tenets and techniques for resection. Thieme Medical Publishers, New York, 2014, Chapter 13, pp 115 to 150.