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This report is being resubmitted for an incident that occurred earlier.Four separate rods were returned for evaluation, indicating that the rods broke bilaterally.The fracture surfaces of all the rods is consistent with fatigue fracture.There are some gouges and scratches along each rod but only minor scratches in the area of the fracture.It was observed that all of the rods have been bent in multiple locations.One of the possible risks associated with pedicle screw systems is device component fracture.No x-rays images could be provided and therefore the construct itself could not be evaluated.These rods were used in a deformity construct and were subject to high stres s.It was stated that the fracture occurred in the lower thoracic spine which is in the area of the thoracolumbar junction.This junction is a natural transition from the mobfle lumbar spine to the relatively immobile thoracic spine.This transition also results in high stress concentrations.Additionally, all of the rods were observed to have multiple bends.Bending plastically deforms the rod and can lead to notching which can create a stress riser and affect the fatigue strength of the rod.It's possible that excessive rod bendlngf contouring, or excessive in-vivo forces contributed to the reported issue.However, the exact cause of the rod breakage cannot be determined.
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