The SMARTdrill’s unique two motor design with constant feed rate (like a drill press or CNC router) and constant rpm drilling with torque sensing converts the surgeon’s subjective tactile feel into objective visual data. This allows the surgeon and the OR team to analyze and record data in real-time.
The GUI provides continuous real-time depth measurement. The GUI also displays the drilling energy which is related to the area under the curve. Drilling Energy (“DE”) is the energy used by the drill bit to remove an aliquot of bone. DE correlates with bone strength and density. DE also correlates with the pullout strength of the implants used.
This actionable intelligence allows the surgeon to be in complete control. The surgeon controls the depth, preventing plunging past the far cortex or into joint spaces. In addition, the surgeon knows the bone density. This allows the proper selection of the right sized and right type of screw, or other implant, the first time, every time.
Position, Torque, Power and Energy are all displayed in the appropriate boxes. Watch the Power vs Depth Curve as it is produced during bone drilling at: Bone Drilling. The GUI starts at about 17 seconds (the video displays an older version of the GUI).
The instantaneous Position (i.e. depth) and instantaneous Power are displayed in the yellow-circles boxes at the top left. The position is the distance the drill bit that has moved out of the drill guide. This gives the surgeon the ability to accurately estimate the screw size needed (to within 0.5 mm). The Power is derived from the Torque measured on the drill bit as it does the Work of cutting the bone. Converting Torque to Power gives a measure of the amount of Energy being consumed at any given moment in the drilling process. The surgeon can chose to monitor either Position vs Power (green circles) or, as is displayed here Position vs Torque on the moving graph in the large display area. The surgeon stops when the graph drops. This is because the efficiency of the tip of the drill bit is zero, so as soon as the tip breaks through the distal cortex the Torque and the Power drop precipitately. In the hyperlinked video you can see that a 3.2 mm drill bit was used to cut into a bicortical Sawbones block (Bone Drilling).
The SMARTdrill® displays the drilling energy in Joules (J) in the Energy Output Box at the top left of the graphical user interface (see above) to the right of the Position Output Box. In the example pictured, the drilling energy was ~25 J for this 3.2 mm drill bit. On the graph above, 25 J of drilling energy correlates to about 400 N of pullout strength if a 4.5 mm self-tapping screw is secured into this hole. Since SMARTdrill® measures Drilling Energy the surgeon will know how much energy is stored in each screw. Therefore, the surgeon will know when enough screws are placed (from empirical data stored in SMD’s Global Bone Database) to achieve the construct strength that is optimal for healing. For those who want to achieve balanced fixation, they can simply compare the energy stored on each side of the fracture. Finally, the surgeon will be able to rest assured that adequate implant purchase and construct strength have been obtained.
© 2018 Smart Medical Devices, Inc.