OBJECTIVE:To investigate the surgical indications, approaches, techniques and prognosis of microsurgical treatment for the brain stem cavernous malformation. METHODS:The clinical data of 16 cases of brain stem cavernous malformation removed microsurgically was retrospectively studied. CT, MRI, and DSA were examined in all the patients preoperatively. As for the location of the lesions, 4 lesions were situated in mesencephalon and pons, 11 in pons, and 1 in medulla oblongata. The average diameter of lesions was 1.3±0.4 cm. The lesions were removed via midline suboccipital transcerebellomedullary fissure and the fourth ventricle (7 cases) , occipital transtentorial (1 case) approach, subtemporal or temporal suboccipital transtentorial approach (4 cases) , and suboccipital retrosigmoid approach (4 cases). The lesions removal were guided with neuroelectrophysiological monitoring and neuronavigation. RESULTS:All the patients had history of hemorrhage, ataxia, and cranial nerve deficits and/or motor or sense dysfunction. The lesions in mesencephalon and pons were removed via subtemporal or temporalsuboccipital transtentorial approach, or by occipital transtentorial approach. The lesions in pons were mainly removed by midline suboccipital transcerebellomedullary fissure and the fourth ventricle approach. Lesions in anterolateral of pons might be operated by suboccipital retrosigmoid approach. Lesions in medullar oblongata were removed by midline suboccipital transcerebellomedullary fissure and the fourth ventricle approach. All the lesions were removed radically under microscope and no death occurred. All the cases were followed up from 4 to 48 months. There was no recurrence or bleeding after operation. CONCLUSION:For brainstem cavernous malformation, the individual microsurgical approach, guidance of intraoperative neuroelectrophysiological monitoring and neuronavigation are the important pledge of successful outcome of operation.