A review of the dhr demonstrated that the mid-c system was manufactured, tested, and released according to apifix specifications.The x-ray demonstrates that the system reached its maximal elongation, which is the weakest point of the rod.Thus, the transverse process below the implant may generate a force acting on the system that can cause the rod breakage.To protect against such force it is necessary to use the trial tool according to the detailed steps as described in the surgical technique guide.The surgery was performed in a minimal invasive approach (mis), which makes it very challenging to verify that the surface below the implant is sufficiently clean from any soft or hard tissue before placing the implant.For this reason, the use of mis technique is not recommended by the company and the surgical technique instructs to perform the surgery with an open midline incision.At the time of this report (aug 2020), the company's incident rate due to implant breakage at maximal elongation is 0.98% and the overall for this category is 6.50%, which is well within the rate reported in the literature for this category ( 0.2%-15.5%) ( cer dms-727 rev r).The risk of the broken rod has been assessed and found to be acceptable (dms#777 rev q1 hazard id 1.8) besides, the company has implemented corrective action resulting in an updated design of the mid-c 125 with elongation of 50 mm, having longer overlap between pole and base which mitigate against cases of maximal elongation.
|