Integrity of craniofacial plating systems after multiple sterilization procedures.

Purpose: To determine the effect of multiple autoclave sterilization cycles on the integrity of titanium plates and screws used in craniofacial reconstruction.

Materials And Methods: Torque to fracture was evaluated for 36 titanium 6AL-4V (Ti 6/4) screws divided evenly into 3 groups and tested as machined (control), after 10 cycles of autoclaving or after 50 cycles of autoclaving. Sterilization was carried out by autoclaving for 15 minutes followed by 8 minutes of drying at 270 degrees to 272 degrees F. The maximum torque attained before fracture was recorded. Rotating beam specimens were crafted from single lots of Ti 6/4, commercially pure titanium grade 4 (CP4) and commercially pure titanium grade 2 (CP2), and then subjected to testing in a standard rotating beam device as machined (control), after 10 cycles of autoclaving or after 50 cycles of autoclaving. The cycles required to fracture the specimen at a given applied stress were recorded for each material and for the number of autoclavings carried out before testing.

Results: Although there was a trend toward decreased strength and increased ability to fracture with increased number of autoclave cycles, this did not reach statistical significance. Torque to fracture testing for 7 mm Ti 6/4 screws showed no significant difference in the maximum torque reached before fracture between controls, those screws that had been autoclaved 10 times (P < .500 +/- 5.70) and those that had been autoclaved 50 times (P < .398 +/- 4.08). Rotating beam specimens of Ti 6/4, CP4, and CP2 showed no significant difference in cycles to fracture regardless of the number of sterilization cycles to which the material was subjected.

Conclusions: Repeated cycles of autoclaving had no significant effect on the integrity of titanium plates and screws routinely used in craniofacial surgery.