Next generation of growth-sparing techniques: preliminary clinical results of a magnetically controlled growing rod in 14 patients

Abstract

SUMMARY: Growth-sparing techniques are commonly used for the treatment of progressive EOS. The standard growing rod (GR) technique requires multiple surgeries for lengthening. The preliminary results of MCGR has shown the comparable outcomes to standard GR without the need for repeated surgery which can be expected to reduce the overall complication rate in GR surgery. INTRODUCTION: Growing rod technique (GR) has been a viable alternative for the treatment of progressive early onset scoliosis (EOS). However, a high complication rate associated with GR has been attributed to frequent surgeries required for lengthening. The safety and efficacy of a non-invasive Magnetically Controlled Growing Rod (MCGR) has been previously reported in a porcine model. We are reporting the preliminary clinical results of the use of this device. METHODS: Multicenter prospective review of early clinical and radiographic data of EOS patients underwent MCGR surgery. Patients who had at least 3 distractions were included. The technique was not significantly different from standard GR surgery. Distractions were performed in clinic without anesthesia or analgesics. The “Target” length (the intended distraction amount in mm which is set on the external magnet) and “Achieved” length (The distraction measured in mm on post distraction radiograph) were also recorded for each distraction. RESULTS: Patients (N=14, F=7,M=7) had mean age of 8y10m (3y6m to 12y7m) and underwent 14 index surgeries, single rod (SR) in 5, dual rod (DR) in 9 and 68 distractions. Diagnosis was idiopathic 5, neuromuscular 4, congenital 2, syndromic 2 and NF one. Mean FU was 9 months (4-15). Average distraction achieved was 4.2 mm per patient. The average time between index surgery and the first distraction was 66 days (28-185) and thereafter was 43 days (23-184). Complications included superficial infection in 1 (SR), prominent implant in 1 (DR) and minimal loss of initial length in 3 (21%) index surgery (all SR). Partial loss of distraction was observed following 14 of the 68 distractions (1 in DR,13 SR). This loss was regained in subsequent distractions. There was no neurologic deficit or implant failure. CONCLUSION: Preliminary results indicate that MCGR appears to be safe and provided the distraction comparable with standard GR procedure without the need for repeated surgeries. No major complications have been observed in the short follow up period …