Visual, dimensional, material and functional analysis could not be performed as the device was not returned.However, x-ray images were provided for evaluation.Post-op images show that four blockers migrated out of the screw head.There is no failure of the screws.Additionally, the rod does not appear to be through the top right side of the construct.Per the surgical technique, there should be approximately 4mm of rod overhanging the screw.Upon further review, it has been determined that the rods are not manufactured by stryker.Device and complaint history records were reviewed, and no relevant manufacturing issues or similar complaints were identified.Per surgical technique: distraction- ensure all blockers are inserted but not tightened using the 4mm blocker inserter.Create distraction on the concavity of the deformity with the distractor.Once the construct is in the right position, lock the blockers with the 4mm blocker driver to maintain the correction.In situ bending- great care must be taken during in situ bending not to overload the bone implant interface.Also care must be used not to acutely notch the rod, which may weaken the implant.Ensure that the closure screws are not completely tightened during rotation maneuvers or the compression/distraction process.Internal fixation devices, such as rods, hooks, screws, wires, etc., which come into contact with other metal objects, must be made from like or compatible metals.Because different manufacturers employ different materials, varying tolerances and manufacturing specifications, and differing design parameters, components of the system should not be used in conjunction with components from any other manufacturer¿s spinal system.Any such use will negate the responsibility of stryker spine for the performance of the resulting mixed component implant.Using different manufacturer implants is one of the contributing factors to blockers loosening post-op.It was also reported that the blockers were tightened during final distraction.This may have contributed to blockers loosening post-op as when the distraction is released the rods and screw may change the position.The root cause of the reported event is multifactorial and include: using stryker implants with other incompatible system.Surgeon putting too much force through instrumentation.Too short of a rod placed in construct.Final tightening of the blocker during distraction.
|