Vertebral Growth Around Distal Instrumented Vertebra in Patients With Early-Onset Scoliosis Who Underwent Traditional Dual Growing Rod Treatment

Abstract

Study Design. Retrospective radiographic study. Objective. To investigate the growth of the vertebrae around distal instrumented vertebra (DIV) in patients with early-onset scoliosis (EOS) who underwent dual growing rod (DGR) treatment. Summary of Background Data. Previous studies indicated that DGR was likely to preserve or even stimulate the spinal growth. However, report pertaining to the effect of growing rod on the growth of individual vertebral body is rare. Methods. The EOS patients treated with DGR who had at least four lengthenings and 5-year follow-up were enrolled. Spine radiographs at index surgery and final follow-up were reviewed. The height, width, and depth of vertebral body from DIV–2 to DIV+2, and the height of the adjacent intervertebral space (IVS) were measured. The percentage of growth was calculated. Results. Thirty-one patients (mean age, 6.2 ± 2.5 years old) met the inclusion criteria, 74.2% (23/31) of whom were female. The average follow-up was 6.2 years (range, 5.0–10.4 yr). The measured vertebrae were divided into DIV group (n = 65), DIV- group (DIV-1 and DIV-2, n = 60), and DIV+ group (DIV+1 and DIV+2, n = 47). There were 33, 90, and 78 measured IVSs in DIV, DIV–, and DIV+ group, respectively. The total percentage growth of vertebral height was significantly higher in DIV– group than that in DIV and DIV+ groups (56.6 ± 20.3% vs. 45.6 ± 18.0% and 42.7 ± 16.2%, respectively, P ≤ 0.001). The vertebrae in DIV– group also had the highest annual height growth rate (8.7 ± 2.6% vs. 7.0 ± 2.4% and 6.6 ± 2.0%, respectively, P ≤ 0.001). A significant decrease of IVS height was observed in DIV– and DIV groups (P ≤ 0.001). Conclusion. Traditional DGR with periodical distraction stimulated the longitudinal growth of the two segments immediately above DIV in patients with EOS. DGR technique had a negative effect on the development of intervertebral discs within distracted levels. Level of Evidence: 3

Smaller Intervertebral Disc Volume and More Disc Degeneration after Spinal Distraction in Scoliotic Children

“…In this investigation, intervertebral discs of a prospectively followed cohort of children with spinal muscular atrophy (SMA) and progressive spinal deformity was evaluated before and after MCGR treatment and matched to untreated SMA children. The cohort is, therefore, homogenous to an extent that is hardly ever achieved in other studies involving EOS patients [ 9 , 19 , 20 ]. Furthermore, most children suffering from SMA are treated with GFSI if their life expectancy allows for this [ 21 , 22 ].…”

“…To our knowledge there are few data published on intervertebral disc changes during GFSI or MCGR treatment [ 9 ]. In this investigation, intervertebral discs of a prospectively followed cohort of children with spinal muscular atrophy (SMA) and progressive spinal deformity was evaluated before and after MCGR treatment and matched to untreated SMA children.…”

“…Demirkiran et al [ 26 ] found some disc degeneration after non-fusion spinal distraction in piglets, but postulated that growing rods did not impair disc health. Rong et al [ 9 ] analyzed intervertebral disc space in heterogenous EOS children treated with dual growing rods. A decreased disc space was shown radiologically by the authors over time [ 9 ].…”

“…Rong et al [ 9 ] analyzed intervertebral disc space in heterogenous EOS children treated with dual growing rods. A decreased disc space was shown radiologically by the authors over time [ 9 ]. Several authors have also postulated spinal stiffness and/or autofusion through GFSI [ 4 , 7 ] and our findings support these observations as there is significantly more IDD after MCGR treatment in the same patients, as well as in comparison to age- and disease-matched controls.…”

“…Hasler et al [ 6 ] have described some of the changes seen in lumbar vertebrae on radiographs after GFSI treatment and Lippross et al [ 8 ] reported reduced vertebral body volume using magnetically controlled growing rods (MCGR). To our knowledge, few data have been published on intervertebral disc changes after GFSI treatment [ 9 ] and no data after MCGRs, despite disc mobility ultimately determining spinal flexibility. To shed light on some aspects of the emerging technique of MCGRs, we conducted a prospective study on a homogenous cohort of patients with spinal muscular atrophy (SMA) and spinal deformity.…”