Aims

To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod.

Aims. Magnetically controlled growing rod (MCGR) systems use non-invasive spinal lengthening for the surgical treatment of early-onset scoliosis (EOS). The primary aim of this study was to evaluate the performance of these devices in the prevention of progression of the deformity. A secondary aim was to record the rate of complications. Patients and Methods. An observational study of 31 consecutive children with EOS, of whom 15 were male, who were treated between December 2011 and October 2017 was undertaken. Their mean age was 7.7 years (2 to 14). The mean follow-up was 47 months (24 to 69). Distractions were completed using the tailgating technique. The primary outcome measure was correction of the radiographic deformity. Secondary outcomes were growth, functional outcomes and complication rates. Results. The mean Cobb angle was 54° (14° to 91°) preoperatively and 37° (11° to 69°) at the latest follow-up (p < 0.001). The mean thoracic kyphosis (TK) was 45° (10° to 89°) preoperatively and 42° (9° to 84°) at the latest follow-up. The mean T1–S1 height increased from 287 mm (209 to 378) to 338 mm (240 to 427) (p < 0.001) and the mean sagittal balance reduced from 68 mm (-76 to 1470) preoperatively to 18 mm (-32 to 166) at the latest follow-up. The mean coronal balance was 3 mm (-336 to 64) preoperatively and 8 mm (-144 to 64) at the latest follow-up. The mean increase in weight and sitting and standing height at the latest follow-up was 45%, 10% and 15%, respectively. The mean Activity Scale for Kids (ASKp) scores increased in all domains, with only personal care and standing skills being significant at the latest follow-up (p = 0.02, p = 0.03). The improvements in Cobb angle, TK and T1-S1 heights were not related to gender, the aetiology of the EOS, or whether the procedure was primary or conversion from a conventional growing rod system. A total of 21 children developed 23 complications at a rate of 0.23 per patient per year. Seven developed MCGR-specific complications. Complications developed at a mean of 38 months (3 to 67) after the initial surgery and required 22 further procedures. Children who developed a complication were more likely to be younger, have syndromic EOS, and have a single-rod construct (6.9 versus 9.3 years, p = 0.034). Conclusion. The progression of EOS can be controlled using MCGRs allowing growth and improved function. Younger and syndromic children are more likely to develop complications following surgery. Cite this article: Bone Joint J 2018;100-B:1187–1200

Aims. Magnetically controlled growing rods (MCGRs) allow non-invasive correction of the spinal deformity in the treatment of early-onset scoliosis. Conventional growing rod systems (CGRS) need repeated surgical distractions: these are associated with the effect of the ‘law of diminishing returns’. The primary aim of this study was to quantify this effect in MCGRs over sequential distractions. . Patients and Methods. A total of 35 patients with a maximum follow-up of 57 months were included in the study. There were 17 boys and 18 girls with a mean age of 7.4 years (2 to 14). True Distraction (TD) was determined by measuring the expansion gap on fluoroscopy. This was compared with Intended Distraction (ID) and expressed as the ‘T/I’ ratio. The T/I ratio and the Cobb angle were calculated at several time points during follow-up. Results. The mean follow-up was 30 months (6 to 57). There was a significant decrease in the mean T/I ratio over time (convex rod at 3 months 0.81, . sd. 0.58 vs 51 months 0.17, . sd . 0.16, p = 0.0001; concave rod at 3 months 0.93, . sd. 0.67 vs 51 months 0.18, . sd. 0.15, p = 0.0001). A linear decline of the mean T/I ratios was noted for both convex rods (r. 2. = 0.90, p = 0.004) and concave rods (r. 2. = 0.81, p = 0.015) over 51 months. At the 24-month follow-up stage, there was a significant negative correlation between the mean T/I ratio of the concave rod with weight (r = -0.59, p = 0.01), age (r = -0.59, p = 0.01), and BMI of the child (r = -0.54, p = 0.01). Conclusions. The ‘law of diminishing returns’ is also seen after serial distraction using MCGR. Compared to previously published data for CGRS, there is a gradual linear decline rather than a rapid initial decline in lengthening. In older, heavier children a reduced distraction ratio in the concave rod of the MCGR device is noted over time. Cite this article: Bone Joint J 2017;99-B:1658–64

Aims

The aim of this study was to compare the surgical and quality-of-life outcomes of children with skeletal dysplasia to those in children with idiopathic early-onset scoliosis (EOS) undergoing growth-friendly management.