MAUDE Adverse Event Report: ALPHATEC SPINE INC POLYAXIAL SCREW, 6.5 MM X 45 MM (TI-6AL-4V ELI); PEDICLE SCREW SYSTEM

Model Number	47000-065-045
Health Effect - Clinical Code	No Code Available (3191)
Date of Event	08/04/2016
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
The proximal portion of the returned arsenal polyaxial screw is currently being evaluated.A follow up report with results of the investigation will be submitted upon completion.
Event or Problem Description
During revision surgery for an unrelated issue (patient condition, coronal imbalance) the polyaxial screw located in the right l5 was found broke just below the tulip.The fracture was not visible on post-op x-ray and appears to have occurred post-operatively and after fusion occurred.The threaded shaft could not be removed and remains entrapped within the l5.
Additional Manufacturer Narrative
Review of the device history records revealed no manufacturing, processing or design related irregularities.The implant was found to be properly manufactured and released in accordance with the device master record.The proximal portion of the broken pedicle screw retrieved from the patient was returned to alphatec for evaluation.The screw shank was fractured at the most proximal portion of the screw shank neck, at the transition to the spherical head.The screw body (or tulip) exhibits noticeable signs of wear where the blue anodize has been worn off the body and a bright polished surface remains.It is unknown whether the removal of the anodize occurred in vivo or whether it was caused during the removal of the specimen, but the anodize wear does not indicate any compromise of the implant since it is not accompanied by any gouging or indication of damage.The polyaxial head remains locked with respect to the angle of the remainder of the bone screw shank and there are no obvious signs of damage to any other portion of the returned implant (with the exception of the broken screw shank).The fracture pattern is consistent with fatigue failure, exhibiting a largely smooth surface with striations where the crack propagated under fatigue until the crack was substantial enough that tearing of the remaining material occurred.The failure pattern and overall appearance of the failed screw shank aligns with the failures seen on screws subjected to standard fatigue testing, which is specifically designed to assess fatigue strength of the screw shank.The side of the screw shank from which the fracture initiated aligns with the portion of the screw body where wear appears to have removed the anodize; based on the angle of the screw shank, it appears that the fracture initiated on the caudal side of the screw - this aligns with clinical findings that 75% of screw breakage occurs on the caudal side (studies have shown that screw shanks have higher axial stress on the caudal side compared with the cephalic side).Additionally, since this was the caudal-most screw, this screw would have been anchoring the construct and thus would have been under more stress than screws higher in the construct.The complaint report states that the patient had successfully fused, and the surgeon suspected that the failure occurred following fusion.This is supported by the fact that no other hardware failures were present.Additionally, the failure was not visible on x-ray during post op visits, which indicates that it was either not present (i.E.Had not yet failed at the time of follow up) or occurred when the construct was no longer subject to significant motion (i.E.The patient had fused).The failure would likely have gone unnoticed entirely, but the patient had returned for an unrelated revision surgery during which the entire construct was removed, resulting in the failure being observed.The failure is in line with the expected failure modes predicted during product testing, and the implant does not appear to have failed prior to providing the necessary stabilization to allow the patient to achieve fusion.Despite the existence of a fusion mass, various strains and loads are still transferred to the implant.The patient was apparently suffering from coronal imbalance (reason for the revision surgery) therefore, uneven loads would have been placed on the existing hardware, likely leading to the failure.

• Brand Name: POLYAXIAL SCREW, 6.5 MM X 45 MM (TI-6AL-4V ELI)
• Common Device Name: PEDICLE SCREW SYSTEM
• Manufacturer (Section D): ALPHATEC SPINE INC; 5818 el camino real; carlsbad CA 92008
• MDR Report Key: 5943653
• Report Number: 2027467-2016-00069
• Device Sequence Number: 18991632
• Product Code: NKB
• UDI-Device Identifier: 00844856070745
• UDI-Public: 00844856070745
• Combination Product (Y/N): N
• Initial Reporter State: SD
• Initial Reporter Country: US
• PMA/510(K) Number: K133221
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2015
• Device Explanted Year: 2016
• Reporter Type: Manufacturer
• Report Source: company representative
• Initial Reporter Occupation: Other
• Type of Report: Initial,Followup
• Report Date (Section B): 08/12/2016

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Operator of Device: Physician
• Device Model Number: 47000-065-045
• Device Catalogue Number: 47000-065-045
• Device Lot Number: 7413907
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 08/20/2016
• Type of Report(Section G): FDA Requested
• Initial Date Received by Manufacturer: 08/20/2016
• Supplement Date Received by Manufacturer: Not provided
• Initial Report FDA Received Date: 09/12/2016
• Supplement Report FDA Received Date: 11/08/2016
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Patient Sequence Number: 1
• Outcome Attributed to Adverse Event: Hospitalization
• Patient Age: 66 YR