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The purpose of this investigation is to evaluate the reported issue of: rod migration.Visual inspection found that locking caps have uneven indentations on the inferior surface where the caps meet the rods.Additionally, there was abrasion visible on the rod consistent with the reported migration event.The wear seen on the locking caps indicates that the rods were not properly aligned with the tulips after final tightening.Abrasive wear along the rod indicates that the rod migrated through the tulip, which is also consistent with improper rod alignment after final tightening.This wear can indicate insufficient locking, hyper lordotic rods, excessive reduction force, or hyper angulated tulips; however, the cause of this event cannot be determined as surgical conditions cannot be replicated.
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