Benefits of fixing 3 proximal vertebral bodies vs. 2 in the treatment of early-onset scoliosis with growing rods

Additional proximal fixation for growing rods in early-onset scoliosis (EOS) may offer a more effective and safer option for severe scoliosis patients with hyper-kyphosis. Here, we compared the outcomes of EOS patients treated with growing rods in which 6 proximal anchor points on 3 vertebrae were used vs. 4 proximal anchor points on 2 vertebrae. The records of patients with EOS treated surgically from January 2016 to December 2017 were retrospectively reviewed. In the Proximal 4 group, 2 vertebral bodies were anchored proximally with 4 anchor points; in the Proximal 6 group, 3 vertebral bodies were anchored proximally with 6 anchor points. Forty-two patients (mean age 5.11 ± 1.93 years) were included; 22 Proximal 4 group, 20 Proximal 6 group. Mean follow-up was 40.86 ± 13.49 months. The decrease in main curve Cobb angle postoperatively was significantly greater in the Proximal 6 group (33.22° vs. 19.08°) (P < 0.05). Cobb thoracic kyphosis (TK) was significantly decreased postoperatively in the Proximal 6 group (mean 20.70°); no significant decrease occurred in the Proximal 4 group. The main curve Cobb angle decrease at last follow-up was significantly greater in the Proximal 6 group (37.84° vs. 24.23°) (P < 0.05). Cobb TK was significantly decreased at last follow-up in the Proximal 6 group (mean 25.17°, P < 0.05); no significant decrease occurred in the Proximal 4 group. Instrument complications were lower in the Proximal 6 group (15.00% vs. 45.45%) (P < 0.05). No proximal junctional kyphosis was noted. Fixing 3 proximal vertebral bodies with 6 anchors improves radiographic outcomes of EOS treated with growing rods, and has a lower rate of screw pull-out.