Objective      To discuss microanatomy features of jugular foramen region in suboccipito-retrosigmoidal minimally invasive approach based on virtual reality image model.       Methods      CT and MRI scaning were performed for 15 adult cadaver heads

and then the image data was inputted into Vitrea virtual reality system to establish three-dimensional anatomy model of jugular foramen region. Different minimally invasive suboccipito-retrosigmoidal approaches were simulated by selecting osseous landmark points on the calvaria and skull base. Anatomic exposures in surgical trajectory following alternation of minimally invasive approach were observed

measured and compared.       Results      Routes simulating suboccipito-retrosigmoidal approach for exposure of jugular foramen region passed under the inferior edge of transverse sinus. Spatial sequence of nerves and vessels in the route was displayed clearly. Vertebral artery and posterior inferior cerebellar artery did not show in the route. Lower cranial nerves did not show in route a. Facial-acoustic nerve complex did not show in route b. Three cases of route b did not involve anterior inferior cerebellar artery. Facial-acoustic nerve complex

anterior inferior cerebellar artery

and lower cranial nerves did not show in route c. Measurement and comparative analysis showed that: the volume of route and cerebella involved in route

route broute aroute c (P0.01); and the volumes of anterior inferior cerebellar artery in route

route aroute b (P0.01).       Conclusion      Different minimally invasive routes of suboccipito-retrosigmoidal approach can expose surgical targets effectively

and their combinations have more advantages.