MAUDE Adverse Event Report: K2M, INC. MESA 2 DEFORMITY UNIPLANAR SCREW; SIZE 6.5X40 MM; THORACOLUMBOSACRAL PEDICLE SCREW SYSTEM

Model Number	6201-36540
Health Effect - Clinical Code	No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	12/09/2020
Type of Reportable Event	Serious Injury
Event or Problem Description
A physician reported that a patient underwent revision surgery to replace a mesa 2 deformity uniplanar screw which did not retain a rod, leading to rod migration approximately six-weeks after implantation post op through imaging.
Additional Manufacturer Narrative
Visual inspection: the screw was in the unlocked position upon receipt.Loss of anodization can also be observed.Functional inspection: the screw was able to be locked and unlocked as intended.Complaint history records review could not be performed as a valid lot code was not provided and could not be obtained.According to the complainant, the outer collet was flush with the inner collet prior to unlocking/removing the subject screw.Screws placed at the most caudal end of the construct are subjected to more stress.Although no trauma was reported, it is possible that normal post-operative patient activities introduced unanticipated loading in the most caudal level of the construct, which may have surpassed the capture strength of the screw and resulted in rod slippage.Additionally, it was reported that there was 3 mm of rod overhang length.At least 5 mm of rod overhang from the most proximal and distal screw is recommended in the mesa 2 surgical technique guide.
Event or Problem Description
A physician reported that a patient underwent revision surgery to replace a mesa 2 deformity uniplanar screw which did not retain a rod, leading to rod migration approximately six-weeks after implantation post op through imaging.

• Brand Name: MESA 2 DEFORMITY UNIPLANAR SCREW; SIZE 6.5X40 MM
• Common Device Name: THORACOLUMBOSACRAL PEDICLE SCREW SYSTEM
• Manufacturer (Section D): K2M, INC.; 600 hope parkway se; leesburg VA 20175
• MDR Report Key: 11181530
• Report Number: 3004774118-2021-00014
• Device Sequence Number: 14474595
• Product Code: NKB
• UDI-Device Identifier: 10888857169173
• UDI-Public: 10888857169173
• Combination Product (Y/N): N
• Initial Reporter Country: NZ
• PMA/510(K) Number: K143334
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Reporter Type: Manufacturer
• Report Source: health professional
• Initial Reporter Occupation: Physician
• Type of Report: Initial,Followup
• Report Date (Section B): 06/22/2021

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?: Yes
• Operator of Device: Health Professional
• Device Model Number: 6201-36540
• Device Catalogue Number: 6201-36540
• Device Lot Number: KPKT
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 03/19/2021
• Initial Date Received by Manufacturer: 12/20/2020
• Supplement Date Received by Manufacturer: 05/30/2021
• Initial Report FDA Received Date: 01/15/2021
• Supplement Report FDA Received Date: 06/22/2021
• 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: Required Intervention