Alternative Surgical Approaches to Juvenile Idiopathic Scoliosis/Adolescent Idiopathic Scoliosis Correction: Anterior Vertebral Body Tethering and Posterior Dynamic Deformity Correction

Introduction: Anterior Vertebral body tethering (AVBT) and Posterior Dynamic Deformity Correction (PDDC) have gained popularity as fusion alternatives for the treatment of juvenile/adolescent idiopathic scoliosis (JIS/AIS). Reviewing newer techniques for scoliosis correction may limit the need for performing rigid fusions. In this study, PDDC is represented by a minimally invasive deformity correction, or Mid-C, system. Given the novelty of these techniques, limited evidence comparing VBT and Mid-C exists to date.

Aims/

Objectives: To provide evidence that VBT and PDDC approaches merit future research as fusion-alternative treatment methods for skeletally immature patients with JIS/AIS.

Methods: A single-center retrospective analysis of AIS or JIS patients who underwent AVBT or PDDC from 2015-2020 with a 2-year follow-up. Patients were dichotomized as VBT or Mid-C. Independent sample t-tests and chi-square analysis were used to compare demographics, pulmonary outcomes, revision analysis, and changes in early onset scoliosis (EOSQ) responses. Analysis was conducted on pre and post-pulmonary function tests to determine the change in forced vital capacity (FVC), forced expiratory volume (FEV1), respiratory volume (RV), and Total Lung Capacity (TLC). Changes in major Cobb angle, minor Cobb angle, and Sagittal Kyphosis from the preoperative to postoperative radiographic analysis were evaluated from baseline and two-year standing full-body plain radiographs.

Results: 22 patients with AIS/JIS who underwent AVBT or PDDC surgery with two-year follow-up (11 VBT, 11 Mid-C) were included in this cohort. The Mid-C group had significantly higher demographics than the VBT group (age: 12.9 vs. 11.2, p=0.004) and (height: 165.7 vs. 154.5, p=001). In pulmonary outcomes, neither the VBT nor Mid-C group had significantly different changes in FVC, FEV1, RV, and TLC from baseline-post op. The Mid-C group displayed a higher incidence of revisions than VBT (72.7% vs. 18.2%, p< 0.01). Radiographic analyses revealed a significant decrease in the change in baseline-postop minor Cobb angle for the Mid-C group compared to the VBT group (VBT: -18.4° vs. Mid-C: -9.7°, p=0.026).

Conclusions: Anterior vertebral body tethering and posterior dynamic deformity correction as alternatives to fusion demonstrate similar deformity correction, pulmonary outcomes, and quality of life scores from baseline to 2 years postop. Although, the Mid-C group has a risk ratio of 3.99 for requiring an unplanned return to the OR. VBT and PDDC both exhibit successful techniques for scoliosis correction, without the need for rigid fusion which often leads to decreased mobility.