Vertebral Body Tethering (VBT) aims to gradually correct scoliosis by utilizing patients' growth, while preserving spine motion. VBT has shown early satisfactory results, while having low complication rates. However, the clinical results and complication profile need to be further defined. We report outcomes at five years post VBT and surgical complications in skeletally immature patients. We reviewed 74 idiopathic scoliosis patients who underwent VBT at a single centre, with a minimum of five-year follow-up. Patients had preoperative, first erect, six-months, one-year, two-year and five-year annual X-rays thereafter. Postoperative data at each of these visits were analyzed. Any interval increases in coronal curve angle equal to or greater than five degrees from the smallest recorded postoperative measure to any other postoperative interval underwent segmental interscrew angle measurements to identify tether breakage. Breakage was suspected when the interscrew angle increased by five degrees or more. Means and standard deviation of specific parameters were calculated. All 74 patients were skeletally immature, the mean age at surgery is 11.8 ± 1.3 years and the mean follow-up time is 63.4 ± 8.4 months. VBT was performed on an average of 7.4 vertebral levels. Instrumented Cobb angle was 48.7° ± 9.2° preop, 17.1° ± 12.3° at the 2-year postop and 25.7° ± 14.0° at the five-year postop. Revision surgery was performed in 12 patients (16.2%). Four patients needed either partial or complete release of the tether due to overcorrection. Two patients needed revision of VBT due to curve progression. Four patients required posterior spinal fusion (PSF) due to curve progression despite VBT. One patient needed a revision of VBT followed by PSF. One patient developed a small dural tear recognized postoperatively, initially treated by a blood patch. This patient complicated by developing an iatrogenic Chiari-like malformation and then needed revision surgery for screw reposition. Forty-nine patients (66%) had a suspected broken tether at the last follow up. The mean time of the first tether breakage is 38.1 ±15 months. In our cohort 66% (49 patients) had a suspected radiological tether break after five years, and 6.8% (five patients) required PSF. VBT offers a significant correction in the coronal and transverse planes postoperatively with a reoperation rate of 16.2 %.
Imbeault et al. (Wed,) studied this question.