A Tentorial Cavernous Angioma With Hemorrhage Mimicking a Hypervascular Brain Tumor.

using this instrument since a high-speed drill is unable to create tapping motion. To examine the convenience of a 1-step drill-tap, we measured the amount of time required for fixing 10 screws. In doing so, we recorded that a conventional 3-step and the new 2-step drills required 189 and 112 seconds, respectively. Although the total operative time did not change extensively, the use of this instrument can reduce the fatigue of the operator. Furthermore, the new 2-step drill facilitates operations during which a large number of screws are required, such as during cranioplasty for treating craniosynstosis. Presently, the resorbable system that makes use of an ultrasound can be fixed by 2-steps. However, this system requires expertise because the adjustment of the insertion is determined by the operator. Therefore, the resorbable system that employs a 3-step process is still mainstream. In conclusion, a 1-step drill-tap is convenient for fixing a resorbable screw.