Pediatric Spine Foundation

Title: Five or more proximal anchors and including upper end vertebra (UEV) protects against reoperation in distraction-based growing rods

Authors: Liam Harris, Lindsay M. Andras, Gregory M. Mundis, Paul D. Sponseller, John B. Means, Growing Spine Study Group, David L. Skaggs

Journal: Spine Deformity

Date: March 03, 2020

Excerpt: Five or more anchors are associated with lower rates of device failure. Proximal anchor placement at or above the UEV resulted in a significant decrease in rates of proximal extension of the construct. The UEV is the point closest to the head where affected spine curvature ends.

Keywords: Early onset scoliosis, Growing rod, Growth friendly, VEPTR, Proximal anchor, Pedicle screw, Rib hook

Summary:

Purpose

The purpose of this study is to examine the impact of anchor placement and other factors on complication and revision rates. This study, conducted on 353 patients with early onset scoliosis (EOS) who underwent surgery using growth-friendly treatment, is the largest study to date on this topic.

Results

  • 77 patients (21.8%) experienced anchor failure by pulling out of or off of bone. Patients with 5 or more proximal anchors experienced lower anchor pullout rates than patients with less than 5 anchors.
  • 40% (141/353) of patients experienced proximal implant failure and 264 reoperations were performed in these 141 patients.
  • Kyphosis data was available for 198 patients. 23.2% (46/198) of these patients required proximal extension, extending the surgical construct farther up the spine towards the head. Preoperative kyphosis and change in thoracic kyphosis were not associated with anchor pullout or proximal revision rates.
  • Initial instrumentation ending below the upper end vertebrae (UEV) of kyphosis was associated with higher rates of reoperation; 28.9% (20/69) compared to 20.1% (26/129) for those instrumented at or above the UEV.
  • Type of anchor used, and type of growth friendly implant used, did not have an impact on rates of anchor pullout or reoperations.

Discussion Points

  • Having five or more proximal anchors can help protect against anchor pullout in patients with EOS. Placing the anchors at or above the UEV can also reduce the need for additional surgeries.
  • Number of reoperations, complications, and returns to the operating room are some of the most important factors in patient satisfaction and cost of treatment. Therefore, the use of 5+ proximal anchors and instrumentation at or above the UEV may improve patient satisfaction. These findings can be valuable for surgeons treating early onset scoliosis and can help improve patient outcomes.