Complications in vertebral body tethering: what are the short term effects on patient reported outcomes?

Abstract

Vertebral body tethering (VBT) has continued to gain popularity for the treatment of idiopathic scoliosis (IS); however, complication and reoperation rates have been reported as high as 25%. There is a paucity of data on the clinical and long-term outcomes of VBT. The purpose of this study is to determine how complications from VBT effect patient quality of life (QOL) up to three years after surgery. In this retrospective cohort study, the patients were identified via an analysis of multi-center electronic medical record data from the Pediatric Spine Study Group (PSSG). All patients who underwent VBT for IS were included. The dataset was screened to include only patients who had patient reported outcome data documented both before and after surgery. Patient demographics, surgery dates, complications, Early Onset Scoliosis Questionnaire (EOSQ) scores, and Scoliosis Research Society (SRS) scores were collected. Complications were classified using the modified Clavien-Dindo-Sink (mCDS) complication classification system. The analysis of QOL after surgery was determined comparing survey scores of patients with and without any complication over time. Additional analysis was similarly performed comparing patients with no or mild complications, defined as mCDS grade I and II, to those with severe complications, defined as mCDS grade IIIA or above. The study consisted of 339 total surveys from 81 patients with EOSQ data and 293 total surveys from 101 patients with SRS data. Among the 81 patients with EOSQ data, 15 patients experienced a complication, with eight patients suffering a severe complication. Among the 101 patients with SRS data, 42 patients experienced a complication, and 22 patients suffered a severe complication. When comparing patients with a complication to those with without a complication, patients with complications had significantly lower total EOSQ scores at 2, 2.5, and 3 years after surgery (p = 0.009, 0.001, and < 0.001 respectively); however, there was no difference in total SRS scores at any time point. In comparing patients with severe complications to pts with mild complications/no complication, patients with severe complications had significantly worse total EOSQ at 2, 2.5, and 3 years after surgery (p = 0.018, 0.002, & < 0.001) and SRS scores at 2, 2.5, and 3 years after surgery (p = 0.040, 0.018, 0.010). Patients with any complication from VBT had worse EOSQ scores at 2 years after surgery. Severe complications (mCDS > IIIA) following VBT manifest with decreasing EOSQ and SRS scores over time and become statistically significant at 2 years and beyond. The magnitude of difference in EOSQ and SRS scores between the groups also increases over time. Longer-term follow-up will ascertain whether these poorer QOL outcomes persist at time points greater than 3 years. Long-term follow up will be important following VBT to compare to PSF for improved patient and parent education.