Behrooz A Akbarnia,1 Kenneth Cheung,2 Hilali Noordeen,3 Paul Sponseller,4 Matthew Shaw,3 Gokhan Demirkiran,5 Muharrem Yazici,5 Hazem Elsebaie,6 George Thompson,7 Charlie Johnston,8 John Emans,9 David Skaggs,10 Growing Spine Study Group11

1San Diego Center for Spinal Disorders CA, USA; 2 University of Hong Kong , China; 3 Royal National Orthopaedic Hospital; 4Johns Hopkins Medical Institutes, Baltimore, MD; 5 Hacettepe University, Turkey; 6University of Cairo, Egypt; 7 Rainbow Babies and Children’s Hospital, OH, USA; 8 Texas Scottish Rite Hospital, TX, USA; 9Boston Children’s Hospital, MA, USA; 10Children’s Hospital of Los Angeles, CA, USA; and 11Growing Spine Foundation, WI, USA.

Objectives: Early results of magnetically controlled growing rods (MCGR) have been promising. The purpose of this study was to perform the first case-matched comparison of traditional growing rods and MCGR patients with minimum 2-year follow-up.

Methods: MCGR patients were selected based on: age younger than 10 years; major Cobb angle of more than 30º; T1–T12 less than 22 cm; no previous spine surgery; and more than 2-year follow-up. Each MCGR patient was matched to a TGR patient by aetiology, sex, single versus dual rods, preoperative age, and preoperative major Cobb angle. Aetiologies were classified by idiopathic, congenital, neuromuscular, and syndromic.

Results: MCGR patients had a mean pre-operative age of 6•8 years (range 3•2–10•4 years) and mean follow-up of 2•5 years (range 1•9–3•0 years). Mean follow-up was greater for patients with traditional growing rods by 1•6 years. Distribution of aetiologies included four neuromuscular patients, four syndromic patients, three idiopathic patients, and one congenital patient. Major Cobb correction was similar between MCGR and TGR patients throughout treatment. Annual T1-S1 growth was 7•1 mm per year for MCGR and 10•6 mm per year for TGR patients. TGR patients had a total of 69 surgeries. MCGR patients had a total of 17 surgeries.

Conclusions: Major curve correction was similar between patients MCGR and TGR patients throughout treatment. MCGR patients had 52 fewer surgical procedures than TGR patients. Annual T1-S1 growth was slightly greater in TGR patients compared to MCGR patients.