Spine Growth Modulation in Early Adolescent Idiopathic Scoliosis: Two-Year Results of Prospective US FDA IDE Pilot Clinical Safety Study of Titanium Clip-Screw Implant

Spine Deform. 2017 Sep;5(5):314-324. doi: 10.1016/j.jspd.2017.02.004.


Study design: Prospective pilot clinical safety study of novel treatment, consecutive case series from first human use in patients with early adolescent idiopathic scoliosis (AIS).

Objective: The primary purpose was to determine the initial safety of a titanium clip-screw implant system for spine growth modulation. The secondary aim was to document curvatures to 2 years postoperatively.

Summary of background data: Spinal growth modulation was documented in preclinical studies. A prospective pilot clinical safety study was then performed under a Food and Drug Administration (FDA) Investigational Device Exemption (IDE) (www.clinicaltrials.gov Identifier: NCT01465295).

Methods: Six subjects with early AIS underwent thoracoscopic placement of titanium clip-screw devices. Eligibility criteria included only patients at high risk for progression to 50°: single major thoracic curve 25°-40°, age ≥10 years, skeletally immature (Risser 0 plus open triradiate cartilages), and if female, premenarchal. Adverse events (AEs), clinical outcomes, and radiographic measures were documented using Good Clinical Practices.

Results: Six consecutive subjects were enrolled, three females and three males aged 12.1 years (±1.7). AEs included one that was device related-mild device migration at 18 months in the most rapidly progressive curve. Procedure-related AEs were mostly pulmonary. A chylous effusion that met the clinical protocol definition of a serious AE resolved after minimally invasive interventions. Major thoracic curves were 34° (±3°) preoperatively and 38° (±18°) at two years (intrasubject change, 4° ± 18°). At 24 months, curves in 3 patients were >45° and 3 were <40°.

Conclusions: A spine growth modulation system undergoing study under an FDA IDE was determined to be safe. Variability in curve response to the implant was high, ranging from progression to correction. Investigational approval was granted by the US FDA for the next cohort of 30 subjects.

Keywords: Adolescent idiopathic scoliosis; Fusionless; Safety; Spine growth modulation; Titanium.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Child
  • Disease Progression
  • Equipment Safety*
  • Female
  • Humans
  • Male
  • Pedicle Screws*
  • Pilot Projects
  • Prospective Studies
  • Scoliosis / physiopathology
  • Scoliosis / surgery*
  • Spine / growth & development*
  • Spine / surgery
  • Surgical Instruments*
  • Titanium
  • Treatment Outcome


  • Titanium

Associated data

  • ClinicalTrials.gov/NCT01465295