Single wire versus double wire loops for median sternotomy closure: experimental biomechanical study using a human cadaveric model.

BACKGROUND: Healing of median sternotomy requires reliable sternal fixation. Although both single and double wire kits are commercially available, no experimental study has compared the two closures in a human cadaveric model. We used a recently described human experimental cadaveric model to compare the stability of the closures.
METHODS: Sixteen fresh adult human cadaveric sternal plates with adjacent ribs were fixed with custom designed spiked stainless steel clamps and attached to a biomechanical testing device. Single No. 5 peristernal and double peristernal closures were tested. The stability of the unions was tested using perpendicular, repetitive force loads increasing from 0 to 800 Newtons at a rate of 0.5 mm/second.
RESULTS: The two study groups did not differ in age or sex. No clamp failures or damage to the specimens occurred. The double peristernal closure exhibited a significantly lower permanent displacement than the single wire group, suggesting a superior strength and stability of that closure.
CONCLUSIONS: To the extent to which this human cadaveric model resembles in vivo median sternotomy, these data suggest that the biomechanical stability of the peristernal double wire closure may exceed that of single wires.