Why create Smart Medical Devices? Because it is time. Today SMD is making orthopaedic drills smarter and safer so the potential for patient injury is minimized. Patient safety is the key to a positive surgical outcome. Surgeons strive for it. Hospitals need to achieve it. Government agencies monitor it. Patients demand it.
Despite decades of advancements in orthopaedic implant technology and attention given to being “biologically friendly” and “minimally invasive,” surgeons are still plunging uncontrollably through, and burning bone, with instruments introduced at least 50 years ago. Other than advancements in power options and minor design changes in drill bits there has been little advancement in orthopaedic power tools. Nothing has been developed to minimize either the thermal injury to bone or the collateral damage to surrounding tissues caused by use of these old tools.
With today’s technology, our tools can evolve. The innovators at SMD know that the drill and driver can inform us regarding the bone they are in contact with. We developed the SMARTdrill® to be an infinitely more sensitive device than present handheld drills. By providing a new level of insight regarding drilling energy, bone strength, bone density and thermodynamics, SMARTdrill® allows the surgeon to know important information about the bone being worked on and significantly reduces, if not eliminates, inadvertent human errors while drilling bone.
Plunging has largely been ignored in today’s operating suites because there is no alternative to using the conventional technology and old instruments. Plunging is the Standard of Care. The drill bit plunges first, and then multiple depth gauge plunges occur. Occasionally, vital structures are injured. Because there is no alternative, vascular injuries, compartment syndromes and nerve injuries are rarely reported or tracked. Fortunately, for surgeons and patients, SMD presented its research and demonstrated the potential to eliminate plunge with vTorq™ Technology Solutions to the AO Foundation, promoting them to add teaching components regarding the inherent problems and iatrogenic injuries associated with plunging.
Conversely, to reduce plunge, surgeons push less and slow forward momentum1, hampering optimal performance of the drill bit, resulting in thermal injury or burn to the bone. Decreasing cutting efficiency results in other effects such as slower feed rates, flute clogging and longer heat exposure time, which is known to cause cell death and tissue injury.
The dilemma, when using a conventional drill, is demonstrated by the graph. Each red curve demonstrates the temperature of a specific drill bit as a function of the force applied. At the nadir of each red curve is the minimum temperature (Tmin), achievable with that drill bit. The force at that point is the most efficient force for that drill bit (energy lost as heat = inefficiency).
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, giving the surgeon a thermodynamic win-win!
© 2018 Smart Medical Devices, Inc.