Evaluation of the lengthening of the magnetically controlled growing rods in juvenile and early-onset scoliosis - 22/12/24

Doi : 10.1016/j.otsr.2024.104117

Stefan Hemmer ^a, Raphael Trefzer ^a, Tobias Renkawitz ^a, Lukas Baumann ^b, Wojciech Pepke ^a,⁎
^a Department for Orthopaedics, Heidelberg University Hospital, Heidelberg, Germany
^b Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany

^⁎Corresponding author.

En prensa. Pruebas corregidas por el autor. Disponible en línea desde el Sunday 22 December 2024

Abstract

Introduction

The treatment of early onset scoliosis (EOS) has seen significant advancements, particularly with the introduction of magnetically controlled growing rods (MCGR). However, a discrepancy between reported and actual rod lengthening during treatment has raised concerns.

Hypothesis

This retrospective study aims to investigate the disparity between reported and actual lengthening of MCGR and to identify factors contributing to the failure of the lengthening process.

Material and methods

Radiographs of the whole spine taken immediately before and after surgery were used for measurements. Documented rod lengthening read from the external remote controller (ERC) was used for analysis. The distraction procedure was classified as failed when the quotient of the measured distraction of MCGR actuators on radiographs and the declared lengthening of the rods using the ERC device was less than 0.3.

Results

Analysis of fifty patients with idiopathic and neuromuscular scoliosis revealed a diminishing discrepancy between ERC-reported lengthening and radiographic measurements after the sixth distraction (p < 0.05), with noticeable failures occurring after the eighth procedure (quotient of mm X-ray/mm ERC of less than 0.3). The bending of MCGRs played a crucial role, with a higher failure rate observed on the convex side of the spinal curve (p = 0.045). Additionally, postoperative thoracic kyphosis (TK) demonstrated a potential association with distraction failure, suggesting altered spinal alignment might affect the efficacy of MCGR treatment.

Discussion

The study emphasizes the importance of precise MCGR bending and vigilant monitoring, especially on the convex side of the spinal curve. We discovered a notable difference between expected and real rod lengthenings, especially after multiple procedures. This emphasizes the importance of closely monitoring MCGR treatments for accurate scoliosis management in young patients.