The teal line, or plunge line, slopes up at a 45 degree angle for a conventional drill. On the red curve, as the force increases the drill bit and bone temperature decrease. But on the plunge line as the force increases the plunge increases, possibly to dangerous levels.
To drill, a certain amount of force must be applied. The surgeon must figure out how much force is enough to ensure that the temperature does not exceed some critical temperature, Tcritical, which should be < 47oC to prevent bone burning. Often it is desirable to select a temperature well below Tcritical to protect adjacent anatomical structures such as nerves.
The optimal trade-off between temperature and plunge occurs at the intersection of the two functions. Studies have demonstrated that experienced surgeons actually ease up on the drill as they anticipate breaching the distal cortex, thereby reducing the plunge1. Of course, there is a thermodynamic trade-off with extra heat being transferred. With conventional technology, the surgeon must always chose between Pmin and Tmin, they cannot have both. Hence the dilemma: to plunge or burn?
The SMARTdrill® limits the plunge to ≤ 0.5 mm, or Pmin. The sloping teal line, or plunge line, becomes a flat line at 0.5 mm. Therefore, the operator can choose the optimal force to drill at (which is greater than Fmin). This results in the lowest possible temperature, Tmin. SMARTdrill® enables the surgeon to chose both Pmin and Tmin.• Enables pre-operative testing of tools • Provides intra-operative cutting performance determination • Virtually eliminates thermal necrosis due to drilling • Gives the surgeon a thermodynamic win-win ➝ Pmin and Tmin
© 2018 Smart Medical Devices, Inc.