LONG-TERM OUTCOMES OF TRADITIONAL GROWTH-FRIENDLY SYSTEMS VERSUS MAGNETICALLY CONTROLLED GROWING RODS IN MANAGEMENT OF EARLY-ONSET SCOLIOSIS: A META-ANALYSIS

The gold standard in the surgical management of EOS was traditional growth-friendly-rods (TGR). More recently, Magnetically Controlled Growing Rods (MCGR) have attracted great interest as they minimize the need for repetitive lengthening surgeries and have practically replaced TGR. Controversy in the literature persists regarding the long-term outcomes of these technologies. In this meta-analysis, we aimed to compare these systems. A systematic search was performed using major databases. Studies comparing TGR to MCGR in the treatment of EOS were included. Study data including patient demographics, spinopelvic parameters, complications, patient-reported outcomes, and cost of technology were collected, pooled, and analysed for any outcome reported by at least two studies. I 2 statistic was used to assess heterogeneity. 24 studies were included. Of the 1909 patients with EOS, 896 and 1013 were treated with MCGR and TGR, respectively. The average minimum follow-up was 3.28±1.86 years. Average age of patients treated with MCGR was 7.89±1.39 years and with TGR 8.2±2.84. In the pooled analysis of all studies, no significant difference was present in the change in cobb angle, T1-T12 height, T1-S1 height, lumbar lordosis, or coronal balance. MCGR led to a significantly larger reduction in thoracic kyphosis (mean difference (MD)= 8.22°, 95%-CI 1.12, 15.32, p=0.02, I 2 =75%) and sagittal balance (MD=13.87mm, 95% CI 2.4–25.34, p=0.02, I 2 =0%). In the pooled analysis of complications, MCGR had a lower likelihood of at least 1 complication (Odds ratio (OR)=0.32, 95% CI 0.16–0.64, p=0.001, I 2 =47%) and infections (OR=0.2, 95%-CI 0.09–0.47, p=0.0002, I 2 =20%). Differences in implant-related complications, unplanned reoperation, and neurological complications did not reach statical significance. When analyzing studies with at least 3 years of follow-up (n=10 studies), TGR led to a significantly larger reduction in cobb angle (MD= 7°, 95%-CI 3.32–9.11, p<0.0001, I 2 =0%), MCGR had a lower likelihood of infections (OR=0.17, 95%-CI 0.03–0.91, p=0.04, I 2 =0%), and no significant difference was found in the likelihood of at least 1 complication or any implant-related complications. No clinically meaningful difference in patient satisfaction was found based on the EOSQ-questionnaires. For MCGR and TGR respectively, the initial cost of implantation was $51,185 vs. $29,339, the cost after 4 years was $88,694 vs. $95,550, and the cost after 6 years was $133,407 vs. $141,537. Both TGR and MCGR remain relevant and effective in the management of EOS. Both systems are associated with comparable health-related quality of life scores. We demonstrated that in the long term, MCGR reduced the odds of infections, but TGR led to a significantly larger reduction in Cobb angle. While these studies have demonstrated cost-neutrality between both technologies in the long-term, there is new emerging call by manufacturers for MCGR replacement every two years, necessitating a re-evaluation of cost-effectiveness of these technologies.