Actuator pin XXXX in magnetically controlled growing rods: two cases.

@entity1 @entity7085 @entity1635 @entity174
BACKGROUND CONTEXT: Magnetically controlled growing rods (MCGRs) are used in the management of @entity1635 ( @entity1635 ). Each MCGR contains a telescopic actuator that serves as the distraction element when stimulated by an external remote controller (ERC), permitting non-invasive lengthening in the outpatient clinic. PURPOSE: This report highlights a subtle cause of MCGR failure. We present the first two reported cases of lengthening pin @entity174 in @entity1 with dual-MCGR constructs. STUDY DESIGN: We present two cases of @entity1 with @entity1635 treated with dual-construct MAGEC (MAGnetic Expansion Control, @entity7085 Technologies Inc, Aliso Viejo, CA, USA) MCGRs. METHODS: A 12-year-old @entity1 presented describing a "popping" sensation in his thoracic spine and resultant grating 36 months following MCGR insertion. RESULTS: A plain radiograph revealed a subtle @entity174 of the lengthening pin within the actuator of the right MCGR. Following identification of this case of implant failure, we reviewed the most recent radiographs of all nine of our @entity1 treated with this MCGR in our institution, resulting in the discovery of bilateral MCGR lengthening pin fractures in an otherwise asymptomatic 11-year-old @entity1 . CONCLUSIONS: Clinicians should have a high index of suspicion of structural implant failure when presented with histories similar to those reported in our first case, or following unsuccessful distraction of MCGRs. In such cases new radiographs should be taken, and all previous images should be reviewed for evidence of this phenomenon. Centers that document MCGR lengthening with ultrasound should obtain plain radiographs every 6 months to evaluate the structural integrity of the implant.
