Growing Rod Surgery

In a very young child, the spine, chest and lungs are still developing, and the growth of the chest in the early years is essential for healthy lungs. A large, progressive scoliosis in a small child threatens both the shape of the spine and the space the lungs need to grow — a problem sometimes called thoracic insufficiency. Fusing the spine at this age would stop the deformity but also stop growth, leaving a short trunk and small chest. The rationale for growing rods is to avoid that dilemma: to control and partly correct the curve while deliberately allowing the spine to keep growing underneath the rods. Growing rods are generally considered when a young child's curve is large and progressing despite, or is unsuitable for, casting and bracing, and where preserving growth of the spine and chest is a priority. The goal is not a final correction, but to manage the curve through the growing years until the child is old enough for a definitive operation, if one is needed.

This is what is generally done, although techniques vary between surgeons and centres. Anchors — screws or hooks — are fixed to the spine at a strong point above the curve and another below it, leaving the curved section in between spanned but not fused. One or two rods (dual rods are common) connect the top and bottom anchors and hold the spine in a corrected position. Crucially, the rods are designed to be lengthened as the child grows. With traditional growing rods, this is done through small repeat operations roughly every six months, in which the rods are surgically distracted a little to keep pace with growth. With magnetically controlled growing rods, the rod contains a small internal magnet-driven mechanism, and it can be lengthened without an operation — in an outpatient clinic, using an external magnetic device, which avoids the repeated anaesthetics and incisions. In both systems the aim is periodic, gentle lengthening over years, and the spine is usually not fused until the end of the process.

Studies show that growing rods correct a large part of the curve — commonly around 50 to 70 percent initially — while allowing continued growth of the spine and chest, and preserving lung development better than an early fusion would. Both traditional and magnetically controlled rods work on the same principle, and the magnetic systems have the clear advantage of avoiding repeated surgical lengthenings. The literature is also honest about the challenges. There is a "law of diminishing returns": each successive lengthening tends to gain a little less height than the last, as the tissues stiffen and the spine partly auto-fuses. Complication rates are high across all growing-rod systems — frequently reported in the region of 44 to 58 percent — including anchors pulling out, rods breaking, and a bend developing above the construct; and magnetic rods specifically can develop mechanical failure of the lengthening mechanism and wear of the metal (metallosis), which has been found in many rods when they are removed. At the end of growth many children have a final, definitive fusion, though some well-aligned graduates can avoid it.

Growing rod treatment is best understood as a years-long programme rather than a single operation, and the family is supported closely throughout. After the first operation the child recovers over a few days in hospital and gradually returns to normal activity, usually with some activity precautions to protect the anchors. Then comes the lengthening phase: with traditional rods this means short, planned procedures every few months; with magnetic rods it means brief, non-invasive clinic visits to lengthen the rod, often with no anaesthetic. Throughout, the child is followed closely with reviews and X-rays to track growth, curve control and the health of the anchors. Families should expect regular visits over several years, and to be prepared for the possibility of unplanned procedures if a complication such as a broken rod or loosened anchor occurs. At the end of the growing phase, a discussion is had about whether a final fusion is needed.

Growing rod treatment is effective at preserving growth, but it is honestly a high-maintenance, complication-prone treatment, and the team explains this fully. Risks include infection (higher with repeated procedures), anchors pulling out, rods breaking, junctional bends developing, and — with magnetic rods — failure of the lengthening mechanism and metal wear. Repeated anaesthetics are a consideration with traditional rods, which magnetic rods help to reduce. The whole approach is a trade-off: accepting the burden and risks of a multi-year, multi-procedure treatment in order to protect spinal and lung growth in a very young child. This page is educational and does not recommend or advise for or against surgery in any individual case.

• —Dual growing rods for the treatment of early-onset scoliosis. (PMC6407943)
• —Traditional dual growing rod technique in early-onset scoliosis and its effects on spinal growth and lung development: mid-term prospective results. (PMC8038906)
• —Comparative efficacy and complications of single and dual growing rods for early-onset scoliosis: updated meta-analysis. (PMID 36509886)
• —Sankar WN et al. Lengthening of dual growing rods and the law of diminishing returns. (PMID 21336236)
• —Growing rods in early-onset scoliosis: the current scenario (review). (PMC10372050)
• —Cheung KM et al. Magnetically controlled growing rods for early-onset scoliosis: a preliminary report. (PMID 26192879)
• —Radiological outcomes of magnetically controlled growing rods for early-onset scoliosis: a multicenter study. (PMC10970737)
• —Thakar C et al. Systematic review of complications associated with magnetically controlled growing rods. (PMID 29675673)
• —Magnetically controlled growing rod for early-onset scoliosis: systematic review and meta-analysis. (PMID 30716487)
• —Cheung JP et al. Frequent small distractions with a magnetically controlled growing rod and avoidance of the law of diminishing returns. (PMID 28031501)
• —Metallosis is commonly associated with magnetically controlled growing rods: results from a multicentre explant database. (PMID 33544222)
• —Analysis of explanted magnetically controlled growing rods from seven UK spinal centres. (PMID 28459777)
• —Final fusion after growing-rod treatment for early-onset scoliosis: is it really final? (PMID 27852908)
• —Is final fusion necessary for growing-rod graduates? A systematic review and meta-analysis. (PMC9837500)
• —Lung function after growing rod surgery for progressive early-onset scoliosis: a preliminary study. (PMID 22340310)
• —Surgical treatment of early-onset scoliosis: traditional growing rod vs magnetically controlled growing rod vs VEPTR. (PMC11721779)