Discrete derivative differential circuit driven system and methods for determining the cure of PMMA intraoperatively after implantation of an orthopedic device
AssigneeWavetest, LLC
InventorsCraig E. Morin, Gary E. Myers, Daniel A. Funk, Quang-Viet Nguyen
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Abstract
The invention comprises a system for securing an implant to a bone comprising an implant which is affixed to the bone, a grout or bone cement comprising a composition that cures in an exothermic reaction and which is capable of securing the implant to the bone in a cured state, and a tester which measures temperature over time to detect a rate change of temperature and uses a novel discrete differentiator circuit to determine when the composition reaches cure.
Claims10
A system for securing an implant to a bone, comprising:
- an implant,
- a grout or bone cement in contact with the implant, said grout or bone cement comprising a composition that cures in an exothermic reaction at a temperature x, the grout or the bone cement being capable of securing the implant to the bone in a cured state, and
- a sensor in contact with the grout or bone cement, said sensor continuously monitors derivative of a rate change of the temperature over time of the grout or the bone cement as compared to the ambient temperature to detect the exothermic reaction, and
- the sensor is joined to a cure determinate circuit which includes a discrete derivative differentiator to determine when the rate change of the temperature reaches an inflection point;
- and joined to an indicator that emits a signal in response to a current emitted to the circuit by the sensor to alert the user that the cure is reached.
The system for securing an implant to a bone as set forth in 9, wherein when a new peak value exceeds a pre-determined fraction of a maximum held peak, value a new peak value detector asserts a reset output to clear a clock or counter.
Dependencies are inferred from the claim text.