Objective       To investigate the clinical significance of subtemporal transtentorial approach under CT bone window neuronavigation to excising the tumor in the petroclival region.        Methods       We compared 16 patients not using navigation system to 27 patients using navigation system in our department from June 2008 to June 2013. All the patients underwent resection of the tumor in the petroclival region by subtemporal transtentorial approach.        Results       In the 16 patients not using navigation system

there were 2 cases of sigmoid sinus injury

2 cases of intracranial infection

1 case of subcutaneous effusion

and no case of recurrence and death in 3~5 year following-up. In the 27 patients using navigation system

there were 4 cases of intracranial infection

2 cases of subcutaneous effusion

and no case of recurrence and death in 1~3 year following-up. In the group former

6 patients (37.5%) underwent total tumorectomy under a microscope

8(50.0%) subtotal tumorectomy and 2(12.5%) partial tumorectomy. In the latter group

16 patients (59.3%) underwent total tumorectomy under a microscope

10 (37.0%) subtotal tumorectomy and 1 (3.7%) partial tumorectomy. There was significant difference in the rate of total tumorectomy between the 2 groups (P0.05).         Conclusion       CT bone window neuronavigation is accurate for positioning. Intraoperative real-time navigation helps to perform safe abrasion of the petrous bone

increase the exposure range safely

and reduces injuries of the sigmoid sinus

bony semicircular canal and neurological functions

improving the prognosis of the patients.