Magnetically Controlled Growing Rods (MCGR) Versus Single Posterior Spinal Fusion (PSF) Versus Vertebral Body Tether (VBT) in Older Early Onset Scoliosis (EOS) Patients: How Do Early Outcomes Compare?

Study Design. Retrospective review of prospective data from multicenter registry. Objective. Compare outcomes of posterior spinal fusion (PSF) versus magnetically controlled growing rods (MCGR) versus vertebral body tethers (VBT) in 8- to 11-year-old idiopathic early onset scoliosis (EOS) patients. Summary of Background Data. In EOS, it is unclear at what age the benefit of growth-sparing strategies outweighs increased risks of surgical complications, compared with PSF. Methods. One hundred thirty idiopathic EOS patients, 81% female, aged 8-11 at index surgery (mean 10.5 yrs), underwent PSF, MCGR, or VBT. Scoliosis curve, kyphosis, thoracic and spinal height, complications, and Quality of Life (QoL) were assessed preoperatively and at most recent follow-up (prior to final fusion for VBT/MCGR). Results. Of 130 patients, 28.5% received VBT, 39.2% MCGR, and 32.3% PSF. The VBT cohort included more females (P<0.0005), was older (P<0.0005), more skeletally mature (P < 0.0005), and had smaller major curves (P < 0.0005). At follow-up, scoliosis curve corrected 41.1 ± 22.4% in VBT, 52.2 ± 19.9% in PSF, and 27.4 ± 23.9% in MCGR (P < 0.0005), however, not all VBT/MCGR patients finished treatment. Fifteen complications occurred in 10 VBTs, 6 requiring unplanned surgeries; 45 complications occurred in 31 MCGRs, 11 requiring unplanned surgeries, and 9 complications occurred in 6 PSFs, 3 requiring unplanned revisions. Cox proportional hazards regression adjusted for age, gender, and preoperative scoliosis curve revealed that MCGR (hazard ratio [HR] = 21.0, 95% C.I. 4.8 - 92.5; P < 0.001) and VBT (HR = 7.1, 95% C.I. 1.4 - 36.4; P = 0.019) patients were at increased hazard of requiring revision, but only MCGR patients (HR = 5.6, 95% C.I. 1.1 - 28.4; P = 0.038) were at an increased hazard for unplanned revisions compared with PSF. Thoracic and spinal height increased in all groups. QoL improved in VBT and PSF patients, but not in MCGR patients. Conclusion. In older idiopathic EOS patients, MCGR, PSF, and VBT controlled curves effectively and increased spinal height. However, VBT and PSF have a lower hazard for an unplanned revision and improved QoL.