Two stage posterior surgery using temporary Magnetically Controlled Growing Rod for severe and rigid Adolescent Idiopathic Scoliosis: A retrospective single-centre cohort study.

INTRODUCTION

To evaluate clinical and radiographic outcomes in patients with severe, rigid Adolescent Idiopathic Scoliosis (AIS) (Cobb angle >100°, flexibility index <30 %) treated using a two-stage posterior-only approach with temporary Magnetically Controlled Growing Rods (MCGR).

MATERIAL AND

METHODS

Between 2019 and 2024, nine patients (eight Lenke 1, one Lenke 3; mean age 15 years; BMI 18.8) underwent staged posterior correction. The first stage included high-density pedicle screw fixation (1.92 screws/vertebra), multiple Ponte osteotomies (mean 4.7), and placement of a concave-side MCGR fixed proximally and distally with a custom construct ("Sistema Quadro"). Postoperative distraction was performed daily for approximately 14 days using an External Remote Controller, achieving a mean rod lengthening of 18.2 mm. The second stage consisted of MCGR removal and definitive posterior spinal fusion.

RESULTS

The main Cobb angle improved from 107.6° to 35.4° (p < 0.0001), corresponding to a mean correction of 65.9 %, obtained in three phases: intraoperative distraction (52.5 %), postoperative lengthening (24.5 %), and final fusion (23 %). Trunk height increased by 9.5 cm and thoracic height by 5.4 cm. Coronal balance improved (25.7 mm-14.4 mm; p = 0.32), as did the clavicle angle (4.4°-0.8°; p = 0.0005). SRS-22 scores rose from 3.3 to 4.4 (p = 0.0011). An inverse correlation was observed between BMI and rod lengthening (PCC = -0.7304; p = 0.026). No complications occurred.

DISCUSSION AND

CONCLUSIONS

A two-stage posterior technique utilizing temporary MCGRs, combined with the "Sistema Quadro" construct and a three-phase correction strategy, offers a safe, effective, and well-tolerated surgical approach for severe, rigid AIS. This method facilitates gradual, controlled deformity correction, optimizes clinical and radiographic outcomes, and minimizes perioperative complications.