Growing Rods vs Single Spine Fusion vs Tethering. Who Wins?

In older patients with early onset scoliosis, while magnetically controlled growing rods, single posterior spinal fusion and vertebral body tether all control curves effectively and increase spinal height, there is, according to a new study, a better post-op quality of life with vertebral body tethering than with either single posterior spinal fusion or growing rods. Although, the lowest rate of unplanned revision surgeries was with patients who had been treated with magnetically controlled growing rods.

The study, “Magnetically Controlled Growing Rods (MCGR) Versus Single Posterior Spinal Fusion (PSF) Versus Vertebral Body Tether (VBT) in Older Early Onset Scoliosis (EOS) Patients,” is published in the February 2022 issue of SPINE.

In the study, the researchers collected early outcome data for each of the three procedures. They extracted prospective data from a multicenter registry of 8- to 11-year-old idiopathic early onset scoliosis patients.

“In early onset scoliosis, it is unclear at what age the benefit of growth-sparing strategies outweighs increased risks of surgical complications, compared with single posterior spinal fusion,” they wrote.

The study included 130 idiopathic early onset scoliosis patients. Eighty-one percent of the patients were female. They were all between the ages of 8 and 11 at the index surgery. Of the 130 patients, 28.5% underwent vertebral body tethering, 39.2% magnetically controlled growing rod insertion and 32.3% single posterior spinal fusion.

The vertebral tethering patients were mostly female (p < 0.0005), older in age (p < 0.0005), and more skeletally mature (p < 0.0005). They also had smaller major curves (p < 0.0005).

The researchers measured scoliosis curve, kyphosis, thoracic and spinal height, complications, and quality of life for each patient both before surgery and at the most recent follow-up.

By follow-up, scoliosis curve was corrected 41.1 ± 22.4% in vertebral body tethering patients, 52.2 ± 19.9% in single posterior spinal fusion patients, and 27.4 ± 23.9% in magnetically controlled growing rod patients (p < 0.0005). Not all the vertebral body tether and magnetically controlled growing rod patients were finished with treatment at the most recent follow-up, however.

Among the vertebral body tether patients, there were 10 who had 15 complications, 6 required unplanned surgeries. Among the magnetically controlled growing rod patients, 31 had 45 complications with 11 requiring unplanned surgery. In addition, 6 single posterior spinal fusion patients had 9 complications, 3 leading to unplanned revisions.

After adjusting for age, gender and preoperative scoliosis curve, the researchers found that magnetically controlled growing rods and vertebral tether patients were at an increased risk of needing revision surgery, but only magnetically controlled growing rod patients were at increased risk for unplanned revision compared with single posterior spinal fusion (HR = 5.6, 95% C.I. 1.1-28.4; p = 0.038).

All patients experienced increases in thoracic and spinal height, but only vertebral tether and single posterior fusion patients had improved quality of life.

Study authors included Catherine Mackey, M.D., Regina Hanstein, Yungtai Lo, and Jaime A. Gomez of Montefiore Medical Center. Majella Vaughan of Children’s Spine Foundation, Tricia St. Hilaire and Scott J. Luhmann, M.D., of Washington University School of Medicine as well as Michael G. Vitale, M.D., of Columbia University Medical Center/Morgan Stanley Children’s Hospital, Michael P.  Glotzbecker of Rainbow Babies & Children’s Hospital, and Amer Samdani, M.D., of Shriners Hospital for Children.