Shilla Growth Guidance System

Traditional growing rods require repeated planned operations to lengthen them. The Shilla concept aimed to avoid this by "guiding" growth instead of driving it: the surgeon corrects and fuses the curve apex, then places sliding screws at the top and bottom that grip the rod loosely enough to let the vertebrae move along it as the child grows. The hope was continued spinal growth with far fewer operations. Like other guided-growth ideas, it is conceptually attractive and was developed by an experienced paediatric team.

The originating group reported reasonable outcomes, including a key five-year follow-up study, and the technique clearly reduces the number of planned lengthening operations. But independent scrutiny has raised important questions. A central concern is how much growth the system actually permits: one study found that Shilla achieved only around a third of the expected normal spinal growth, and commentaries have questioned whether guided growth truly matches the growth promotion of traditional or magnetic growing rods. Comparative studies of Shilla against growing rods have reached mixed conclusions, and a published exchange of letters in the literature directly debates the interpretation of a study comparing Shilla with magnetic rods — a clear sign that the evidence is contested rather than settled. There are also reports of inflammatory particulate debris around the unlocked sliding screws, echoing wider concerns about metal debris from sliding spinal implants. The fair summary is that Shilla reduces the number of operations but may allow less growth than hoped, and that the overall evidence base is modest and disputed.

Shilla sits within a family of "growth-friendly" strategies that also includes traditional growing rods, magnetic growing rods, and other guided-growth systems. No single approach has emerged as clearly superior; each trades off the number of operations, the amount of growth achieved, and the risk of device-specific problems. Systematic reviews and meta-analyses comparing these strategies exist, but the quality of the underlying studies is limited, which is why specialist units weigh the choice individually for each child. Shilla's particular trade-off — fewer operations, but possibly less growth — is exactly the kind of judgement that belongs with an experienced early-onset scoliosis team.

I do not use the Shilla growth guidance system. Early-onset scoliosis surgery is a specialised paediatric field, and these growth-friendly techniques belong with the small number of units that perform and study them. My honest reading of the evidence is that Shilla is a legitimate but contested option: it delivers on reducing the number of operations, but questions about how much growth it truly preserves, and about debris from the sliding components, remain unresolved. Families considering it deserve a balanced account and specialist assessment rather than either enthusiasm or dismissal.

• —McCarthy RE, et al. Clin Orthop Relat Res. 2010. Shilla concept validated in an animal model. PMID 19693636
• —McCarthy RE, et al. J Pediatr Orthop. 2014. Shilla technique, 2-year preliminary human report. PMID 23934092
• —McCarthy RE, et al. J Bone Joint Surg Am. 2015. Shilla at minimum 5-year follow-up. PMID 26446965
• —Sucato DJ. J Bone Joint Surg Am. 2015. Commentary: does guided growth match growth promotion? PMID 26446973
• —Luhmann SJ, et al. J Pediatr Orthop. 2017. Shilla vs growing rods in children under 10. PMID 27043203
• —Luhmann SJ, et al. Spine Deform. 2017. Radiographic outcomes: Shilla vs traditional growing rods. PMID 28622904
• —Nazareth A, et al. Spine Deform. 2020. Shilla achieves only ~1/3 of normal T1-S1 growth. PMID 32096132
• —Haapala H, et al. Spine. 2020. Shilla vs magnetically controlled growing rods in neuromuscular/syndromic EOS. PMID 32858743
• —Kim G, et al. J Neurosurg Pediatr. 2022. Systematic review and meta-analysis of surgical interventions for EOS. PMID 36152334
• —Toth JM, et al. Eur Spine J. 2022. Inflammatory particulate debris around unlocked sliding screws. PMID 35695968
• —Wilkinson JT, et al. J Pediatr Orthop. 2019. Curve modulation and apex migration at 5-year follow-up. PMID 31393297