Fixing device, installation tool and fixing method of the cranial flap

A fixing method of the cranial flap, comprising the following steps:

• (A) assembling the installation tool;
• (B) setting the assembled installation tool on the connecting rod to complete the assembly of the cranial flap fixation device;
• (C) placing the assembled cranial flap fixation device around cranial flap to be fixed;
• (D) rotating the driving part and driving the loading part to rotate through the over torque protection mechanism until the over torque protection mechanism is separated from the driving part and/or the loading part;
• (E) repeating the step (D) until all the cranial flap fixation devices are evenly screwed around the cranial flap;
• wherein the cranial flap fixation device in the above steps comprises a connecting rod, and an upper disc and a lower disc disposed on the connecting rod, wherein the upper disc and the connecting rod are connected by threads, a fastening hole is set on the upper disc;
• further comprises an installation tool sleeved on the connecting rod, wherein a locking column is disposed on the bottom end of the installation tool, the size of the locking column matches the size of the fastening hole;
• the installation tool comprises a driving part, a loading part and an over torque protection mechanism disposed between the driving part and the loading part, the driving part drives the loading part to rotate by the over torque protection mechanism, the loading part is used for tightening the cranial flap fixation device, when the torque of the driving part acting on the over torque protection mechanism is larger than the threshold value, the over torque protection mechanism will be separated from the driving part and/or the loading part.