H6: health effect- clinical code: 4582.Health effect- impact code: 4629.Medical device problem code:1260.Component code: 568.Type of investigation: 3331; 10.Investigation findings: 3243.Investigation conclusions: 22.H10: review of the device history records did not identify any manufacturing or processing related irregularities related to the screw shank geometry, tulip geometry, or other physical features.Qir reports indicate all inspected features were acceptable.Material certs were present from the supplier (in compliance with >135 ksi yield strength requirements for shank) along with all other cofc's.No other indications of misuse or heavy wear on the screw tulip exterior, interfacing helical flange threads, or hexalobe-screwdriver interface were observed during evaluation.Explanted shank is fractured through the neck and into the base of the shank sphere.Collateral surface damage noted on screw shank from improvised explantation.Non atec extraction device is cold welded to the screw shank.Tulip head was separated from the construct via bolt cutters with rod still locked down in the tulip (with set screw).No evidence of set screw cross threading; set screw is securely locked down.It is unknown when the index surgery or revision surgery dates were.Index surgery trajectory and location are also unknown, but screw size (ø9.5mm x 50mm) suggests implantation in the sacropelvic regions.Supporting construct details and patient physical characteristics are also unknown.This failure is consistent with screw failure expectations observed when used in loading conditions that exceed the design parameters set forth in mechanical performance testing.In this instance, the pedicle screw appears to have been exposed to fatigue stresses beyond the performance loads for which it was designed or intended.This can be precipitated by environmental factors such as falls, patient postop weight bearing activity, or other adverse patient events.Other factors that may contribute to complications and adverse reactions (i.E.Construct instability) can include poor fusion development (non-union and/or pseudoarthrosis) or patient bmi.
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