DESIGN PERFORMANCE OBJECTIVES:
Better accuracy than competitor’s product
Maintain calibration for a minimum 6 month use life without requiring recalibration
No component failure during 6 month calibration life
DESIGN OBJECTIVES TO MEET PERFORMANCE OBJECTIVES:
Maintain a calibration accuracy of ±5% of set value over 6 month calibration life (competitor’s accuracy is ±10%)
Maintain calibration accuracy for a minimum of 3000 cycles
Maintain calibration accuracy for a minimum of 200 autoclave cycles using a standard steam sterilization cycle
No component failures during any of the above tests
SUMMARY OF RESULTS:
Testing on the three different torque mechanisms used in Bradshaw Medical torque devices was performed by three different large orthopedic companies. Calibrated torque wrenches at various torque settings were provided to these companies. In most cases a minimum of 5 units were provided at each torque value.
Test protocols were developed by each company, in conjunction with Bradshaw Medical, that would meet the requirements for these companies and the performance criteria identified in Bradshaw’s program objectives.
The most stringent protocol was to meet an instrument life analysis of 1320 cycles based on 4 surgeries per month, times 60months, times 5.5 screws tightened per surgery based on historical data. This was developed from their historical utilization of 4 inventory turns per month, 5 years (60 months)estimated instrument life, and an average of 5.5 screws per surgery (1.75 levels per surgery where 1 level = 4 screws and 2 levels = 6 screws. The sample size was identified at 6 units based on FDA guidance for spinal systems. Acceptance criteria indicated all units must meet the cycle and autoclave cycle life testing and maintain the ±5% stated accuracy throughout the test program.
Testing was first performed by tightening 6 screws for each cycle, and repeating this for 200 cycles (1200 clicks). These same units then were subjected to a phase 2 test program which consisted of the following:
Soak parts in Terg-A-Zyme for 15-20 minutes
Rinse by soaking in water for at least 2 minutes
Soak parts in Cidex OPA for 15-20 minutes
Soak in water for 3-5 minutes
Dry at 275 degrees F for 5-7 minutes
Steam Autoclave for 30 minutes at 270°F (132°C) based upon existing steam sterilization time of 25 minutes.
Connect unit to the Instron machine and torque 6 assemblies until click occurs
This was repeated for 200 cycles.
Units tested met the customer’s requirements.
The second customer performed similar testing with the units subjected to 90 autoclave cycles and 4000 clicks with acceptable results. The third customer evaluated 15 units and subjected them to 6 autoclave cycles with 6 clicks after each autoclave, all with acceptable results of ±5% following the test program.
In-house testing has also been performed on an Instron for 3000 straight clicks with results well within the ±5% of set value.
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