Fig. 1

Resection a middle cerebellar peduncle and pontine tegmentum cavernous malformation by full neuroendoscopic telovelar approach. A CT imaging shown a small hematoma in the right fourth ventricle, middle cerebellar peduncle and pontine tegmentum. B MRI SWAN sequence suggested a cavernous malformation; C patient in the lateral prone position with the head fixed in a head-holder and slightly flexed; D a midline suboccipital craniotomy was performed, and the posterior arch of C1 was preserved; E under neuroendoscopic view, the inferior edge of the tonsils, uvula, PICA and obex was exposed. F The tela choroidea, inferior medullary velum and floor of the fourth ventricle were visualized and protected. G The hematoma in the fourth ventricle was exposed and removed. H The hematoma in the middle cerebellar peduncle was exposed and removed. I A small, cavernous malformation in the pontine tegmentum was identified and removed. J The cavity was checked after the operation. K Postoperative CT scan shown the hematoma was removed completely. L Histopathological examination revealed a cavernous malformation