A comparison of growth among growth-friendly systems for scoliosis: a systematic review.

Background Context: The optimal method for surgical treatment of early onset scoliosis is currently unknown. Although the aim of growth-friendly systems is to reduce the curve and maintain growth, there is no consensus on how to measure spinal growth during and after the treatment. Different measurements of different segments (T1-S1, T1-T12, instrumented length) are used for different time points to evaluate growth. The aim of this review is to assess what measurements are used and to compare the growth-friendly systems based on spinal growth during treatment.

Methods: The electronic MEDLINE, EMBASE, and Cochrane databases were systematically searched for original articles that reported growth for traditional growing rods (TGR), vertical expandable prosthetic titanium rib expansion technique (VEPTR), Shilla, magnetically controlled growing rods (MCGR), and Luque-trolley systems. All measurements were recorded, and weighted averages calculated in centimeter per year were compared.

Results: We included 52 studies (26 TGR, 12 MCGR, 6 VEPTR, 4 Luque trolley, 1 Shilla, and 3 mixed). Often only one segment was reported (T1-S1 length in 22 studies, T1-T12 length in two studies, and instrumented length in five studies). The remaining 22 studies reported T1-S1 length in combination with T1-T12 length (15 studies) or instrumented length (eight studies). Spinalgrowth achieved by initial correction only was a considerable 3.9 cm (based on 34 studies) as well as the spinal growth achieved by the final fusion surgery (2.3 cm in four studies). To specifically assess growth achieved with the system, length gain after initial surgery and before final fusion in growth system graduates was considered. Only four TGR studies reported on this "true" spinal growth with 0.6 and 0.3 cm/y in the T1-S1 and T1-T12 segment, respectively.

Conclusions: Reporting on spinal growth is currently inadequate and does not allow a good comparison of different techniques. However, all systems often report growth similar to Dimeglio's T1-S1 spinal growth of 1 cm/y. It should be recognized though that a considerable portion of the reported spinal growth is the result of the initial and final surgical correction and not due to the growth-friendly implant.