Levels l3-l5 were instrumented in an open procedure of a high bmi patient (39.4).Instrumentation started on left top to left bottom.Once the surgeon got to the right side of the patient, he was having difficulties with all the patient's soft tissue and odd pedicles and decided to abort and complete the procedure with the stealthstation.In order to re-register with the stealthstation, a second spin was performed.The surgeon noticed in the scan that l4 screw was placed inferiorly to the pedicle, whereas during the case, the system displayed the position of the screw in the pedicle.The screw was removed and repositioned.The investigation by the company revealed that the calibration of the screwdriver was not performed as indicated in the xvs user manual.In the first two attempts to calibrate the screwdriver according to the xvs user manual instructions, the system notified the user that the screwdriver is too bent and did not enable the successful completion of calibration.At this point, the screwdriver was calibrated using the calibration method that is designed for fixed instruments and not swiveled instruments.Calibration was completed, however, the risk in this system misuse is that the system may display the tracking information inaccurately.The xvs user manual specifically warns the user not to use bent or flexible tools as this may affect the system's accuracy.Hence, it seems that the cause of the event is system misuse.The investigation results will be reviewed with users in the site and the need to follow calibration instructions will be emphasized.
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