Oral Posters: Values and Outcomes in Spine Surgery

Presented by: E. Rebich - View Audio/Video Presentation (Members Only)

Author(s):

A. Aminian(1), E. Rebich(1)

(1) Children's Hospital Orange County, Orthopedic Sugery, Orange, CA, United States

Abstract

The treatment of adolescent idiopathic scoliosis (AIS) with hybrid constructs has been widely reported in recent literature. Apical pedicle screw implantation can be challenging in pediatric population, so sublaminar bands can be used to limit some of the potential neurological complications with malpositioned screws. Bands allow safe fixation with greater laminar surface area, especially in apical vertebral bodies (AVB) with dysplastic pedicles. Additionally, bands require no image guidance and decreased blood loss. The dual band used has one shared malleable lead allowing fast bilateral band fixation with one pass under the lamina. Also different band connector designs allowed distinct corrective forces to be applied. So offset derotation (OD) connectors on the concave AVB and low profile (LP) connectors on the convex contralateral AVB were used. Both connectors allowed translational forces, but the OD connector also enabled derotation of the AVB around the rod. We hypothesized that a hybrid construct with two different band connectors at the apex would achieve correction of coronal and sagittal deformities with minimal loss of correction over time.
A single-center, single-surgeon IRB-approved retrospective cohort data was collected from December 2014 to August 2016. Twenty AIS patients aged 10-21 years were consented with Lenke curve types 1-3. Patients with prior spinal surgery, MRI abnormalities, neuromuscular, thoracogenic, cardiogenic scoliosis were excluded. Posterior releases with osteotomies were performed. Hooks were used at the proximal aspect of the construct and pedicle screws placed distally with bands along the apex of the curve.
Radiographic analysis was performed using Surgimap® software for 1 year follow-up in 16 patients. Postoperatively, thoracic kyphosis [T4-T12] improved from 26°± 11.6 to 35.0° ± 6.7, with a lordosis change [L1-L5] of 58.9° ± 10.9 to 62.0° ± 9.7. For hypokyphotic patients, [N=5], kyphosis improved from 11.8°± 5.5 to 33.0° ± 5.1, with a lordosis change of 50.2° ± 5.2 to 64.8° ± 6.3, showing a gain higher than literature values. Overall, the mean coronal correction rate was 32% for UPPER, 69% for MAIN, 64% for LUMBAR curves. There was no loss of correction in UPPER thoracic curves, improvement of 6.3 degrees in MAIN thoracic and a loss of 0.3 degrees in LUMBAR curves. The mean operative time was 239.5 ± 25.1 min, with an average blood loss of 367.5 ± 90.7 mL. Wilcoxon tests showed a significant gain in kyphosis post-operatively, p = 0.008, followed by significant decrease in Cobb angle p< .0001. There were no peri-operative complications. No proximal or distal junctional kyphosis was observed.
This study showed the effectiveness and safety of a unique hybrid band system in correcting coronal deformity and restoring thoracic kyphosis. Sublaminar bands are a safe and effective option for scoliosis correction. This study is limited by the fact this is a single center, single surgeon, retrospective study with 1-year follow-up. This cohort will be followed to confirm the preliminary results.

Figure A&B