Risk of early complication following anterior vertebral body tethering for idiopathic scoliosis.

purposeThe purpose of this study was to determine peri-operative morbidity associated with anterior vertebral body tethering (aVBT) for idiopathic scoliosis.

methodOf 175 patients treated with aVBT, 120 patients had 2 year follow up and were included in this study. Prospectively collected clinical and radiographic data was analyzed retrospectively.

resultsPre-operatively, the mean patient age was 12.6 year (8.2-15.7 year), Risser 0-3, with main thoracic scoliosis 51.2° (40-70°). Immediately post-operative, scoliosis improved to 26.9° (6-53°; p < 0.05), at 1-year post-operative was 23.0° (- 11 to 50°; p < 0.01 vs immediate post-op) and at 2-year post-operative was 27.5° (- 5 to 52; p = 0.64 vs immediate post-op). Pre-operative T5-T12 kyphosis was 16.0° (- 23 to 52°), post-operative was 16.9° (- 7 to 44°), at 1-year was 17.5° (- 14 to 61°) and at 2-year was 17.0° (- 10 to 50°; p = 0.72 vs pre-op). All patients underwent thoracoscopic approach, EBL 200 ml (20-900 ml), surgical time 215.3 min (111-472 min), anesthesia time 303.5 min (207-480 min), ICU stay of 0.2 day (0-2 days), and post-operative hospital stay 4.5 days (2-9 days). During the in-hospital peri-operative period, there were no unplanned return to the operating room (UPROR) and there was a 0.8% rate of complication: one pneumothorax requiring reinsertion of chest tube. By 90 days post-operative, there was no UPROR and a 5% rate of complication. Five additional patients developed complications after discharge: one CSF leak treated with blood patch injection in the clinic and resolved, two pleural effusions requiring chest tubes, one superficial wound infection and one pneumonia treated with outpatient antibiotics. By 1-year post-op, there was a 1.7% rate of UPROR and 8.3% rate of complication. Four additional patients developed complications beyond 90 days: two upper limb paresthesia required outpatient medical management, one CSF leak which initially treated blood patch injection in the clinic initially which then required UPROR, and one compensatory lumbar curve add on that was treated with extension of the tether. By 2-years post-op, there was a 6.7% rate of UPROR and 15.8% rate of complication. 9 additional complications developed after 1 year. One curve progression, one keloid scar, one right leg weakness, 4 cable failures and 2 curve overcorrections.

conclusionThis large, multicenter series of aVBT demonstrated a 15.8% complication rate and a 6.7% UPROR rate at 2 year post-operatively. This early study during the learning curve of aVBT found higher rates of CSF leaks and overall complications than would be expected for PSFI at 1 year post-operatively and a higher rate of overall complications and of UPROR than would be expected for PSFI at 2 year post-operatively. As is common with new procedures, the complication rate may fall with further experience.