The Spring Distraction System for Growth-Friendly Surgical Treatment of Early Onset Scoliosis: A Preliminary Report on Clinical Results and Safety after Design Iterations in a Prospective Clinical Trial

Abstract

Background: The Spring Distraction System (SDS) is a dynamic growth-friendly implant to treat early onset scoliosis (EOS). Previous SDS studies showed promising results in terms of curve correction and complication profile. Nevertheless, complications did occur, which led to modifications in the implant design. The main iterations were a larger rod diameter and a more sagittal stable sliding mechanism. The purpose of this study was to investigate the performance of these iterations. Methods: All patients treated with the modified SDS and >1 year follow-up were included. Radiographic outcomes, severe adverse events (SAEs), unplanned returns to the operating room (UPRORs) and health-related quality of life (HRQoL) were investigated. Results: Seventeen EOS patients (three congenital, four idiopathic, nine neuromuscular, one syndromic) were included. Mean age at surgery was 9.5 ± 2.5 years. Similar to the first generation SDS, about 50% initial correction was achieved and maintained, and spinal growth was near physiological. Most importantly, SAEs and UPRORs were diminished and favorable with 0.10/patient/year. In addition, HRQoL increased during the first year postoperatively, indicating the implant was well accepted. Conclusion: These preliminary results indicate that the iterations of the SDS are effective in terms of reducing SAEs and UPRORs and increasing HRQoL in patients with EOS.

Health-related quality of life in early onset scoliosis patients treated with the spring distraction system: what to expect in the first 2 years after surgery

“…At UMC Utrecht, SDS treatment is offered to EOS patients with an indication for “growth-friendly” treatment, except in patients with diseases that compromise soft tissue- or bone strength such as osteogenesis imperfecta or Marfan syndrome. The surgical technique for SDS has been described previously [ 5 , 7 , 17 ]. Anchors and rods are implanted comparable to TGR, but the rods are not fixated in side-to-side connectors, but are allowed to slide freely in the connector.…”

“…Statistical significance was set at p < 0.05. The false discovery rate (i.e., the rate of Type I errors due to multiple testing) for the post hoc analyses after analyzing the main effects was controlled at 5% through the Benjamini–Hochberg method, and the adjusted p values were calculated [ 7 ]. All statistical procedures were performed with IBM SPSS Statistics for Windows, Version 27.0.…”

“…1 ). It provides continuous and dynamic distraction forces and achieves stable curve correction and near-normal growth without the need for repetitive surgical or outpatient lengthenings [ 4 – 7 ]. However, the effect of SDS treatment on health-related quality of life (HRQoL) has not yet been characterized.…”

Diagnostic and therapeutic strategies in early onset scoliosis: A current concept review

“…54,55 The available short-term results are encouraging but must stand the test of time. 56,57 With the persistent challenges of surgical growth guidance associated with current techniques, discussion has recently been raised regarding the optimal treatment of an older, biologically more advanced population of patients with EOS, the so-called "tweeners," in whom in addition to growth-friendly approaches primary final fusion may be considered. Based on a three-round survey, consensus (≥70% agreement) was reached among experts in regard of chronological age (8-10 years in girls; 9-11 years in boys), as well as inclusion of Sanders stage (<4).…”

The Risk and Benefits of Various Innovations in Fusion and Fusionless Surgery for AIS

“…In contrast to adolescent scoliosis, early-onset scoliosis requires growth-friendly treatment to allow the spine and chest to grow to adult proportions. As PSF and VBT do not allow for extensive growth, Tabeling et al recently presented a novel growth-friendly system for treating early-onset scoliosis [ 6 ]. In contrast to traditional growing rods, by the application of one or two springs around rods in sliding connectors, the scoliosis is corrected by continuous distraction forces and the spine is kept dynamic.…”