Treatment of early onset spinal deformities with magnetically controlled growing rods: a single centre experience of 30 cases

PURPOSE: The treatment of early onset scoliosis continues to be a major challenge, even when using motorized growth-sparing implants. We report on 30 cases operated on with magnetically controlled growing rods (MCGRs) at our institution, analyzing radiological parameters and complications, comparing our results with the literature and presenting a special implant fixation technique. A separate focus highlights the challenges of conversion from previous non-motorized implants. METHODS: Consecutive case series. The nature and effects of complications were recorded for all patients. Radiographic evaluations were performed for patients with a minimum follow-up of two years. Separate analyses were carried out for patients who were previously treated with non-motorized growth-sparing implants RESULTS: There were 12 documented complications in 11/30 (37%) patients leading to 13 unplanned returns to the operating room. In all, 18/30 patients had a minimum follow-up of two years. Major curve and main kyphosis, as well as T1 to T12 and T1 to S1 distances significantly improved with MCGR implantation, however, less in patients converted from previous growth-sparing surgical treatment. While the achieved correction of the major curve was maintained, there was a loss of kyphosis correction with subsequent implant lengthening. Gain in implant length decreased with increasing number of extensions. CONCLUSION: Despite improved patient’s comfort, MCGR show a considerable complication rate. Coronal plane deformities can be well controlled, but diminished implant lengthening is already apparent within two years after MCGR implantation. Central databases should help to clarify unresolved aspects and optimize the treatment of these young patients. LEVEL OF EVIDENCE: IV