Anterior vertebral body tethering shows mixed results at 2-year follow-up

Study designRetrospective chart review.ObjectiveTo report 2-4-year outcomes of anterior vertebral body tethering (AVBT) for adolescent idiopathic scoliosis (AIS).Summary of background dataAVBT is a relatively new procedure to correct AIS spine curvature and few outcomes studies have been published.MethodsPatients from 2015 to 2017 with 2-year follow-up were included. Successful outcomes were defined as curves 35 degrees or less without revision surgery. We also compared outcomes between thoracic and lumbar ABVT.ResultsThere were 19 AVBTs in 17 patients, 13 thoracic and 6 lumbar. Nine curves (47%) in nine patients (53%) were successful. Preoperative kyphosis averaged 26 degrees in the successful group and 14 degrees in the unsuccessful group (P=0.0337). Immediate correction for lumbar ABVTs (76%) was greater than thoracic ABVTs (43%) (P=0.0140). Correction per level per month was greater in lumbar ABVTs (2.9 degrees vs. 0.1 degrees) (0.0440). Preoperative Sanders Maturity Scale (SMS) was 3.7 for successful cases and 2.5 for unsuccessful cases (P=0.0232). Final SMS was 7.7 for successful cases and 5.7 for unsuccessful cases (P=0.0518). All successful cases and 50% of unsuccessful cases were mature at final follow-up (P=0.0294). There were four (24%) revision procedures, and three involving lumbar AVBTs. There were nine (47%) broken tethers.ConclusionsDespite several final curves>35 degrees, four revisions, and nine broken tethers, the majority of patients (53%) were considered successful. Lumbar ABVTs correct more intraoperatively and faster postoperatively. Patients who are tethered during or slightly after the curve acceleration phase of growth may have more successful outcomes than patients tethered prior to the curve acceleration phase. AVBT requires further study with longer outcomes to define best practices for indications, level selections, and surgical techniques.Level of evidenceIV.

Automated summary

This study reports on the 2-4 year outcomes of anterior vertebral body tethering (AVBT) for adolescent idiopathic scoliosis (AIS) patients. The research found that successful cases had an average preoperative kyphosis angle of 26 degrees, compared to 14 degrees in unsuccessful cases; meanwhile, lumbar AVBT had a higher immediate correction rate (76%) and correction speed than thoracic AVBT.