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Visual inspection: a screw, two rods and four blocker were returned for evaluation.The rods are concomitant products.Slight deformation was observed on the screw threads.No other visual anomalies were identified.Post-op x-rays were provided showing that a top blocker migrated out of the screw.The remaining 3 blockers are dislodged.Functional inspection: all blockers were able to hold down a test rod in the screw.Device and complaint history records were reviewed, and three complaints appeared for this lot number.All four prs are associated with one event no other similar events were identified for the reported lot number.No further action is required at this time.From the xia 4.5 surgical technique: once the correction procedures have been carried out and the spine is fixed in a satisfactory position, the final tightening of the blockers is performed.To final tighten; use the anti-torque key and the torque wrench: step 1: place the anti-torque key over the screw head.Step 2: place the torque wrench through the anti-torque key until it is guided into the blocker.Step 3: line up the two arrows to achieve the final tightening torque of 8nm.The torque wrench indicates the optimal torque force that must be applied to the implant for final tightening.Note: do not exceed 8nm during final tightening.The anti-torque key must be used for final tightening.The anti-torque key performs two key functions: allows the torque wrench to align with the tightening axis; helps to maximize the torque needed to lock the implant assembly.From the xia ifu: while the expected life of spinal implant components is difficult to estimate, it is finite.These components are made of foreign materials which are placed within the body for the potential fusion of the spine and reduction of pain.However, due to the many biological, mechanical and physicochemical factors which affect these devices but cannot be evaluated in vivo, the components cannot be expected to indefinitely withstand the activity level and loads of normal healthy bone.The most likely root cause of the construct loosening is inconsistency in tightening the blockers.
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