MAUDE Adverse Event Report: APIFIX LTD MID-C 125; POSTERIOR RATCHETING ROD SYSTEM

Model Number MID-C 125

Device Problem Detachment of Device or Device Component (2907)

Patient Problem Insufficient Information (4580)

Event Date 10/20/2021

Event Type  Injury  

Event Description

The patient complained about a"sound in the back" and the x-ray images indicate that the nut of the distal apifix screw has detached.

Manufacturer Narrative

First investigation: production process analysis: a review of the dhr demonstrated that the mid-c system was manufactured, tested, and released according to specification.User (surgeon and patient) information analysis: on the first revision surgery (mdr#3013461531-2021-00037) the implant was replaced to a longer size mid-c rod, however the lower and upper screws from the original surgery were kept in place.In addition, the company requested the doctor to provide x-rays following the first revision to assess the trajectory between the rod and screw.After the second revision surgery, the company also asked the surgeon/distributor to return the failed screw and nut to the company for failure analysis.The company will conduct an inspeaction and further investiagtion of these parts once they are received.Design: the nut coming loose from the screw might result from improper torquing, or from inserting the screw in a wrong trajectory that disables proper nut torquing.The lp pedicle screws incorporate an additional safety mechanism to prevent nut loosening which was implemented according to eco-62.An intentional thread defect is designed into the distal region of the m6 thread so that the nut can be rotated smoothly over the proximal teeth, but hits the defect just before the end of travel.The intentional defect increases the amount of friction between the threads of the pedicle screw and nut to prevent its loosening.This is meant as a secondary safety feature with final torquing of the nut to 7nm being the primary safety feature.Once the nut is threaded on the screw and final torqued past the area of the thread defect, ideally it should not be removed.The surgeon chose not to replace the already implanted screw but only the nut (along with a new mid-c rod).Than he needs to be sure to achieve the proper final nut torquing (tightening) of 7nm to insure adequate locking of the nut with the screw in the abscebce of the threaded post intentional defect that acts as a secondary locking mechanism.Risk assessment: at the time of this report the risk of nut loosening duo to any reason is 0.7%.The total rate for this complication "loss of fixation to bone or connection between implants" is 2.58% and is well within the rate reported in the literature as defined in clinical evaluation report dms-727 rev t.

• Brand Name: MID-C 125
• Type of Device: POSTERIOR RATCHETING ROD SYSTEM
• Manufacturer (Section D): APIFIX LTD; 1 hacarmel street; kochav yokneam bldg; yokneam elit, 20692 07; IS 2069207
• Manufacturer (Section G): APIFIX LTD; 1 hacarmel street; kochav yokneam bldg; yokneam elit, 20692 07; IS 2069207
• Manufacturer Contact: adi prager ; 1 hacarmel street; kochav yokneam bldg; yokneam elit, 20692-07 ; IS 2069207
• MDR Report Key: 12954658
• MDR Text Key: 281909124
• Report Number: 3013461531-2021-00044
• Device Sequence Number: 1
• Product Code: QGP
• Combination Product (y/n): N
• Reporter Country Code: GM
• PMA/PMN Number: H170001
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Foreign,User Facility,Distributor
• Reporter Occupation: Other
• Type of Report: Initial
• Report Date: 12/07/2021

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?: No
• Device Expiration Date: 01/28/2021
• Device Model Number: MID-C 125
• Device Catalogue Number: AFS-125-050
• Device Lot Number: AF-01-069-21
• Initial Date Manufacturer Received: 10/18/2021
• Initial Date FDA Received: 12/07/2021
• Date Device Manufactured: 01/28/2021
• Is the Device Single Use?: Yes
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Initial
• Patient Sequence Number: 1
• Patient Outcome(s): Required Intervention