Preliminary clinical and radiographic outcomes of a hybrid single MCGR and apical sliding construct in severe early-onset scoliosis.

BACKGROUND: Early-onset scoliosis (EOS) management aims to control deformity while preserving spinal and thoracic growth. While magnetically controlled growing rods (MCGR) reduce the surgical burden, unilateral MCGRs are prone to mechanical failure and lack true 3-dimensional (3D) apical control. Conversely, apical fusion techniques restrict continuous spinal growth.

OBJECTIVE: To evaluate the preliminary clinical and radiological outcomes of a fusionless hybrid construct utilizing a concave single MCGR and a contralateral convex sliding rod with Active Apex Control (APC) in patients with severe EOS.

METHODS: A retrospective review of 20 EOS patients (14 females, 6 males) treated with the hybrid technique and followed for a minimum of 12 months (mean 25 ± 6 months). The mean age at index surgery was 99 months. Radiographic parameters, including major Cobb angle, kyphosis, apical vertebral translation (AVT), apical vertebral rotation (AVR, Nash-Moe), and T1--L5 length, were analyzed preoperatively, at early post-op, and at final follow-up.

RESULTS: The mean major Cobb angle significantly improved from 88° ± 22° preoperatively to 49° ± 18° postoperatively (p = 0.001) and was maintained at 50° ± 15° at the final follow-up (p = 0.658). Mean preoperative hyperkyphosis (61°) was restored to 30° at final follow-up. AVT decreased from 60 to 26 mm postoperatively and was clinically maintained at 32 mm at final follow-up. The transverse plane deformity (AVR) significantly improved postoperatively (p = 0.001) without significant progression during the lengthening period (p = 0.655). Continuous spinal growth was preserved, yielding an acceptable true T1-L5 growth rate of 8 mm/year. Seven patients (35%) required unplanned surgeries.

CONCLUSION: Preliminary results indicate that the hybrid combination of a single concave MCGR and a convex sliding rod is a feasible surgical option for severe EOS. The system provides maintenance of coronal, sagittal, and rotational deformity correction while allowing for continuous spinal lengthening. The unplanned revision rate was 35%, and instances of rod breakage were effectively managed by replacing the broken MCGR with a passive sliding rod.

LEVELS OF EVIDENCE IV: Case series.