Metal implants and bone are screwed together in order to help bone fractures heal faster or to correct skeletal malpositions. When it comes to this, the depths of the drill holes are usually measured mechanically by hand. Handling the gauging tool is time consuming, cumbersome and highly prone to errors. However, it is essential for a successful outcome of the healing process that the screws match exactly with the depths of the drill canals. A wrong screw length can still be corrected, provided that it is detected by x-ray confirmation during surgery. Additional x-ray exposures and the repeated corrections impose a burden on both patients and the medical team. However, a certain percentage of falsely determined screws is likely to escape detection and will put the healing process at risk.
"Intelli-Drill" measures the length of the drill canal during drilling with precision and does so in one work step. A solid-borne sound sensor records the oscillations which occur when the drill passes through the various a layers of bone and registers the time until the drill reemerges from the bone. Parallel to the oscillatory profile, the length of the pathway is also measured. The distance between the site where the drill is applied for drilling and is later pulled out of the bone is then exactly identical to the depth of drill canal.
Hundreds of thousands interventions of this kind are applied in Germany alone, worldwide there are several million. The method presented can be applied in surgery or in nonmedical areas. This invention is addressed to manufacturers of medical devices and surgical instruments.
Osteosynthesis, surgery, measurement engineering
Surgical measurement engineering, solid-borne sound, bone fractures, orthopedics
Licensing, sales, cooperation and further development
University Bremen, Bremen Institute for Metrology, Automation and Quality Science (BIMAQ),
and Roland Klinik, Bremen