Efficacy of Anterior Vertebral Body Tethering in Skeletally Mature Children with Adolescent Idiopathic Scoliosis: A Preliminary Report

Abstract

Background: Anterior vertebral body tethering (AVBT) offers a dynamic fusion less correction option for children with adolescent idiopathic scoliosis (AIS). Few existing clinical studies evaluating novel AVBT in skeletally immature children have questioned the midterm efficacy with concerns of overcorrection and curve progression with remaining growth. The current study investigates the effect of this technique in skeletally mature children (Risser ! 4 and Sanders ! 7) with AIS with limited remaining growth potential.Methods: We evaluated skeletally mature children with AIS who underwent the AVBT technique for a single structural major curve between 408 and 808 with !50% flexibility on dynamic radiographs and a minimum of 1 year of follow-up. Pertinent clinical and radiographic data collected include skeletal maturity, curve type, Cobb angle, sagittal parameters, and a patient-reported outcome measure Scoliosis Research Society-22 (SRS-22) questionnaire.Results: All 10 children were female with a mean age of 14.9 6 2.7 years at the time of surgery. The mean followup was 24.1 6 3.6 months. The mean Risser and Sanders scores were 4.2 6 0.6 and 7.2 6 0.6, respectively. Three patients had major thoracic curves, and 7 patients had thoracolumbar/lumbar curves. Cranial and caudal instrumented levels were T5 and L4. Mean preoperative Cobb's angle was 52.08 6 11.68 and was corrected to 15.98 6 6.88 on the first erect postoperative radiograph, with stabilization of corrected curve at the 1-year follow-up (mean Cobb's angle of 15.38 6 8.78). Mean preoperative and postoperative SRS-22 scores were 78.0 6 3.2 and 92.5 6 3.1, respectively (P , .01). No complications were noted until the last follow-up.Conclusion: Our preliminary experience with this novel AVBT as an alternative technique to fusion to stabilize progressive idiopathic scoliosis in skeletally mature children is promising.

Vertebral Body Tethering in 49 Adolescent Patients after Peak Height Velocity for the Treatment of Idiopathic Scoliosis: 2–5 Year Follow-Up

“…Yet, in the limited studies inclusive of more skeletally mature patients, overcorrection rates were reduced while maintaining acceptable rates of clinical success in the more mature patient. Hegde et al reported on 10 skeletally mature patients (Sanders ≥7) and found a 71% correction rate of the major Cobb with no incidence of re-operation or conversion to fusion at latest follow-up [ 20 ]. Alanay et al assessed VBT outcomes stratified by Sanders skeletal maturity and found 55% correction of the major Cobb with no incidence of mechanical complications or overcorrection in the Sanders 6–7 cohort as compared to a 60% mechanical complication rate and 80% overcorrection rate in the Sanders 2 cohort in their study [ 2 ].…”

The timing of tether breakage influences clinical results after VBT

“…Furthermore, it allows for a good correction on the sagittal plane [3] and it may prevent adjacent segment degeneration [4,5], a common downfall of spine fusion. VBT can be employed both in its growth-modulating form for skeletally immature patients (VBT-growth modulation, VBT-GM) and as a tissue remodelling technique in patients who are approaching or have reached skeletal maturity (VBT-anterior scoliosis correction, VBT-ASC) [6][7][8]. Growth modulation is regulated by the Hueter-Volkmann principle [9,10], while tissue remodelling follows the principles of Wolff's law.…”

Minimum 3-year experience with vertebral body tethering for treating scoliosis: A systematic review and single-arm meta-analysis

“…Further studies should be performed on the follow-up results from the time of VBT surgery up to when the patients are skeletally mature, or even longer, and on the poor outcome after VBT that leads to the eventual conversion to PSF. 43…”

“…VBT can achieve certain deformity correction during the initial operation, control the patient's spinal growth potential, and make the concave side grow faster than the convex side, thereby realizing continuous correction during subsequent spinal growth while controlling the progression of deformity (Figure 2). Sixteen studies reported the major curve pre-and post-operation and at final follow-up 13,14,22,23,25,[28][29][30][31]34,35,37,38,41,43,45 (Figure 3). Ten studies reported kyphosis angle pre-and post-operation and at final follow-up 13,14,23,28,30,34,37,38,41,45 (Figure 4).…”