Researches on anatomical features of subtemporal transtentorial approach with three dimensional virtual reality technique

Objective To evaluate the application of virtual reality technology via the subtemporal transtentorial approach by comparing the virtual three-dimensional (3-D) microanatomy of the temporal bridging veins as part of the resection of tumors across the petrosal crest and the actual microanatomy of the temporal bridging veins in surgery.Methods The experiment included two groups:virtual group (25 cases of tumor crossing petrosal crest),and surgery group.Before operation,imaging data of patient heads obtained from computerized tomographic angiography (CTA),and magnetic resonance angiography (MRA)etc.were loaded into the Dextroscope workstation.After co-registration of the different modalities of imaging data and segmentation of the veins,the dissection of temporal bridging veins was simulated.The anatomical simulation of VR was the same as that done by surgeons in actual anatomy.We compared the number of branches of each vein,and the position of the veins in VR lab and in operation.Results Four basic configurations of veins were found:venous lakes running in the tentorium before emptying the sinuses (16％,8 hemispheres),candelabra of veins uniting to form one large drainage (42％,21 hemispheres),single independent draining veins (18％,9 hemispheres) and multiple independent draining veins (24％,12 hemispheres) in virtual group,and 10 (43.47％),10(43.47％),4 (17.39％) and 6 (26.08％) in surgery group,respectively.The distributions of anatomical terminations of temporal bridging veins were divided into three groups:transverse area (54.35％,50),tentorium area (23.91％,22) and petrosal area (21.74％,20) in virtual group,and 53.33％ (24),26.67％ (12),and 9 (20％) in surgery groupm respectively.The distance from the emptying point of the labbe veins to the sigmoid transverse point was (20.12±2.51) mm,and the proportion of fore-placed type veins of labbe was 8.33％ in virtual group,and that was (24.12 ±3.68) mm,and 0 in surgery group respectively.The anatomical features of labbe veins found during the operation of the 23 patients with tumors extended from middle fossa to posterior fossa and were identical to those seen in presurgical planning.Conclusion Virtual reality technology can accurately simulate the anatomical feature of temporal bridging veins,which facilitates the planning of individual operations in neurosurgery. Key words: Temporal bridging veins;  Virtual reality technology;  Microsurgical anatomy