Magnetically controlled growing rods in early onset scoliosis

Outcome of distraction-based growing rods at graduation: a comparison of traditional growing rods and magnetically controlled growing rods

INTRODUCTION

Distraction-based growing rods have been considered as an alternative surgical option for the operative treatment of EOS. TGR has been challenged by MCGR, which is reported to have the advantage of non-invasive lengthening with fewer planned returns to theatre. This study explores the radiographic outcomes, Unplanned Returns to the Operating Room (UPROR) and complication profile of both the procedures at the end of the planned growing rod treatment with either TGR or MCGR.

METHODS

We included all the EOS cases from the PSSG database that underwent either TGR or MCGR with spine-based proximal anchors, followed up to the time of graduation. Any crossover or hybrid procedures were excluded. 549 patients (409 TGR and 140 MCGR) were eligible for review. We measured the coronal curve magnitude, Kyphosis, T1-T12, T1-S1 and L1-S1 lengths at 4 time points (before and after the index surgery and before and after the definitive surgery).

RESULTS

The TGR group were slightly younger at the time of the index procedure (7 years for TGR vs. 8.5 years for MCGR, p < 0.001). We noted an improvement in all radiological parameters after the growing rod implantation. The spinal lengths increased through the lengthening period, while the coronal curve magnitude and the kyphosis increased. The kyphosis normalized following the final fusion, the coronal curve magnitude reduced further with a further increase in spinal lengths. The final follow-up from the time of the index implantation to the definitive surgery was 5.1 years (IQR 3.8) in TGR and 3.5 years (IQR 1.65) in the MCGR groups. The total number of complications was fewer in the MCGR group. The overall risk of UPROR was lower in the MCGR group and implant breakage was less in the MCGR group by 4.7 times.

CONCLUSIONS

This study confirms the equivalence of both the distraction-based growing rods systems from the radiological stand-point, during the lengthening phase and at the time of the definitive surgery. The TGR was more kyphogenic during the lengthening period. The complications and UPROR were fewer in the MCGR groups.

Increased lengthening frequency does not adversely affect the EOSQ scores in magnetically controlled growing rod surgeries in 133 subjects followed to final fusion

PURPOSE

Magnetically Controlled Growing Rod (MCGR) allows frequent outpatient rod lengthening when treating Early Onset Scoliosis (EOS) patients. But there is lack of expert consensus on the optimal MCGR lengthening interval. EOS 24-Item Questionnaire (EOSQ) is validated for assessing health-related quality of life (HrQOL), family burden, and satisfaction. This is the first study assessing how MCGR lengthening intervals affects patient-perceived outcomes.

METHODS

This is a multicentred cohort study with subjects recruited from 2012 to 2018 and followed till fusion. EOS subjects who underwent MCGR surgeries were grouped into high, medium or low lengthening interval subgroups based on 16 and 20 week cut-offs. Repeated measure analysis was performed on EOSQ's specified 12 domains. EOSQ results were taken: before index surgery, after index surgery, and prior to definitive treatment. Demographic, clinical and radiographic data were included in model adjustment.

RESULTS

133 subjects with mean follow-up of 3.5 (± 1.3) years were included, with 60 males and 73 females; 45 idiopathic, 23 congenital, 38 neuromuscular, and 27 syndromic patients. Mean Cobb angle at surgery was 67° (± 22°) with mean age of 8.3 (± 2.5) years. Between groups, clinical and radiographic parameters were comparable. Higher EOSQ scores in medium lengthening interval subgroup was present in fatigue (p = 0.019), emotion (p = 0.001), and parental impact (p = 0.049) domains, and overall score (p = 0.046). Trendline contrast between subgroups were present in general health (p = 0.006) and physical function (p = 0.025) domains.

CONCLUSION

Patient-perceived outcome improvements appear similar between lengthening interval subgroups. All MCGR lengthening intervals were tolerated by patients and family, with no negative impact observed.

LEVEL OF EVIDENCE

Prognostic Level III.

Comparison of traditional growth rods and magnetically controlled growing rods in early-onset scoliosis: a case-matched mid term follow-up study

PURPOSE

Early-onset scoliosis (EOS) has always been a challenging situation for spine surgeons. The aim of treatment is to control the direction of curve progression to allow for the complete development of lungs. Among all the growth constructs available, traditional growth rods (TGR) and magnetically controlled growth rods (MCGR) are most widely used. The MCGR has been introduced a few years back and there is a dearth of long-term follow-up studies. The purpose of this study is to compare the effectiveness of TGR and MCGR for the treatment of EOS.

METHODS

All patients of EOS managed with either TGR or MCGR were included in the study. The patients managed with other methods or having follow-up < 2-years were excluded from the study. A total of 20 patients were recruited in the MCGR group and 28 patients were recruited in the TGR group. Both groups were matched by etiology, gender, pre-operative radiological parameters, and complications including unplanned surgeries.

RESULTS

The mean age in our study was 7.90 years in the MCGR group and 7.46 years in the TGR group. The mean duration of follow-up in the MCGR group was 50.89 months and in the TGR group 94.2 months. Pre-operative cobb's angle in the coronal plane and T1-S1 were comparable in both groups with a mean cobb's angle of 65.4 in MCGR and 70.5 in TGR. The mean T1-S1 length in the MCGR group was 36.1cms and in the TGR group was 35.2 cms (p = 0.18). The average increase in T1-S1 length was 1.3 cm/year in the TGR group and 1.1 cm/year in the MCGR group (p > 0.05). The TGR patients underwent 186 open lengthening surgeries and 11 unplanned surgeries for various complications. The MCGR group has 180 non-invasive lengthening with only 4 unplanned returns to OT for various causes.

CONCLUSION

The curve correction was similar in both TGR and MCGR groups. The average T1-S1 length achieved on final follow-up was similar in both groups. The MCGR patients have attained similar correction with fewer invasive procedures and lesser complications compared to the TGR group.

Patients treated by magnetic growing rods for early-onset scoliosis reach the expected average growth

INTRODUCTION

Magnetic controlled growing rods (MCGRs) are one of the most common procedures to treat early-onset scoliosis (EOS). One of the major concerns is that patients treated with MGCR do not reach an adequate height with MGCR. The present study has one of the largest sample sizes of EOS patients treated by MGCR. This study aims to demonstrate the efficacy of the treatment with MGCR in EOS patients, comparing our results with the estimated growth.

METHODS

Patients were consecutively enrolled from July 2011 to July 2022. The same surgical equipe performed all the procedures. The mean length of the patients was assessed by X-ray (T2-T12 and T2-S1 distance) by a team of expert radiologists. The estimated growth by Dimeglio was compared with the mean elongation obtained by year.

RESULTS

65 patients were included. 16 patients underwent final surgery. In group 1, patients reached a growth of 3.6 ± 8.7 mm (T2-T12) and 9.6 ± 27.6 mm (T2-S1). In group 2, patients grew 5.4 ± 5.7 mm (T2-T12) and 9 ± 9 mm (T2-S1).81% of the estimated elongation during the treatment was obtained during the first surgery. The difference between Dimeglio's estimated growth and the value obtained by MGCR was -4.3 ± 8.7 mm(T2-T12) and -12.3 ± 12.2 mm (T2-S1) in group 1 (p < 0.001) and -1.1 ± 4.2 mm (T2-T12) and -6.6 ± 6.0 mm (T2-S1) in group 2 (p = 0.001).

CONCLUSIONS

MGCR patients reached and overlapped the growth target according to the score by Dimeglio. However, the value of growth tended to reduce over the years. Lastly, obtaining the most significant elongation possible at the first surgery is mandatory, comprising 81% of the total value.

Predictive Parameters for Chêneau Brace Efficacy in Patients with Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective consecutive cohort study.

OBJECTIVE

For patients with mild to moderate adolescent idiopathic scoliosis (AIS), bracing is the standard therapy to prevent progression of deformity. Still, not all patients benefit from treatment in the same way. Therefore, predictive parameters are needed to determine if patients are likely to benefit from brace therapy.

METHODS

Fourty-five AIS patients treated with a Chêneau brace were evaluated retrospectively. Inclusion criteria were based on SRS-criteria. Whole spine X-rays were performed pre-brace, in-brace, and at least 6 months after termination of brace treatment. Gender, age, Risser's sign, vertebral rotation determined by Nash and Moe grading system, in-brace correction and in-brace time per day were parameters evaluated. Treatment success and failure groups were compared to determine possible predictive parameters for successful brace treatment.

RESULTS

Chêneau brace treatment was successful preventing curve progression in 69%. We found significant differences between success and failure group concerning age (14 ± .22 vs 12.4 ± .4; P < .001) and Risser's sign (1.71 ± .16 vs .5 ± .17; P < .001) at beginning of brace treatment. Most significantly, initial in-brace curve correction was correlated with successful outcome after brace treatment (r = .64 (P < .001)).

CONCLUSIONS

As one of few studies adhering to the criteria defined by the Scoliosis Research Society our study shows reliable predictive parameters for Chêneau brace treatment success in patients with AIS. Data shown in this paper will help to differentiate AIS patients who are likely to benefit from adequate bracing therapy from those who could rather benefit from early surgical treatment.

Perioperative Complications and Health-related Quality of Life Outcomes in Severe Pediatric Spinal Deformity

STUDY DESIGN

Prospective multicenter cohort study.

OBJECTIVE

To evaluate perioperative complications and mid-term outcomes for severe pediatric spinal deformity.

SUMMARY OF BACKGROUND DATA

Few studies have evaluated the impact of complications on health-related quality of life (HRQoL) outcomes in severe pediatric spinal deformity.

METHODS

Patients from a prospective, multicenter database with severe pediatric spinal deformity (minimum of 100 degree curve in any plane or planned vertebral column resection (VCR)) with a minimum of 2-years follow-up were evaluated (n=231). SRS-22r scores were collected preoperatively and at 2-years postoperatively. Complications were categorized as intraoperative, early postoperative (within 90-days of surgery), major, or minor. Perioperative complication rate was evaluated between patients with and without VCR. Additionally, SRS-22r scores were compared between patients with and without complications.

RESULTS

Perioperative complications occurred in 135 (58%) patients, and major complications occurred in 53 (23%) patients. Patients that underwent VCR had a higher incidence of early postoperative complications than patients without VCR (28.9% vs. 16.2%, P =0.02). Complications resolved in 126/135 (93.3%) patients with a mean time to resolution of 91.63 days. Unresolved major complications included motor deficit (n=4), spinal cord deficit (n=1), nerve root deficit (n=1), compartment syndrome (n=1), and motor weakness due to recurrent intradural tumor (n=1). Patients with complications, major complications, or multiple complications had equivalent postoperative SRS-22r scores. Patients with motor deficits had lower postoperative satisfaction subscore (4.32 vs. 4.51, P =0.03), but patients with resolved motor deficits had equivalent postoperative scores in all domains. Patients with unresolved complications had lower postoperative satisfaction subscore (3.94 vs. 4.47, P =0.03) and less postoperative improvement in self-image subscore (0.64 vs. 1.42, P =0.03) as compared to patients with resolved complications.

CONCLUSION

Most perioperative complications for severe pediatric spinal deformity resolve within 2-years postoperatively and do not result in adverse HRQoL outcomes. However, patients with unresolved complications have decreased HRQoL outcomes.

Evaluating consensus and uncertainty among treatment options for early-onset scoliosis: new generation and international perspectives

PURPOSE

It is currently unknown how treatment preferences differ between a senior group of U.S. spinal surgeons, a new generation of U.S. surgeons, and non-U.S. surgeons with regard to the treatment of early-onset scoliosis (EOS). The purpose of this study was to evaluate clinical consensus and uncertainty among treatment options for patients with EOS to understand how they compare between these three cohorts.

METHODS

11 senior pediatric spinal deformity surgeons in the U.S., 12 "junior" surgeons in the U.S., and 7 surgeons practicing in non-U.S. countries were invited to complete a survey of 315 idiopathic and neuromuscular EOS case scenarios. Treatment options included: conservative management, distraction-based methods, growth guidance/modulation, and arthrodesis. Consensus was defined as ≥ 70% agreement, and uncertainty was < 70%. Chi-squared and multiple regression analyses were performed to evaluate the associations between case characteristics and consensus for different treatments.

RESULTS

Although all 3 cohorts of surgeons chose conservative management most frequently, the non-U.S. cohort of surgeons chose distraction-based methods more often, particularly for neuromuscular cases. In both U.S. surgeon cohorts, there was consensus for conservative management in idiopathic patients aged 3 or younger regardless of other factors, whereas non-U.S. surgeons selected distraction-based methods for some of these patients.

CONCLUSION

Just as research studies are being conducted to find approaches to optimally manage the EOS population, future research efforts should focus on identifying the reasoning behind treatment preferences in different cohort of surgeons, as this will allow the interexchange of information which can ultimately improve EOS care.

LEVEL OF EVIDENCE

V.

Early-onset scoliosis: a narrative review

Early-onset scoliosis (EOS) is defined as any spinal deformity that is present before 10 years old, regardless of etiology.

Deformity must be evaluated based on the intercorrelation between the lungs, spine, and thorax.

Curvatures of early-onset have increased risk of progression, cardiorespiratory problems, and increased morbidity and mortality.

Progression of the deformity may produce thoracic insufficiency syndrome, where a distorted thorax is unable to support normal respiratory function or lung growth.

Management and treatment of EOS should pursue a holistic approach in which the psychological impact and quality of life of the patient are also taken into consideration.

Growth-friendly surgical techniques have not met the initial expectations of correcting scoliotic deformity, promoting thoracic growth, and improving pulmonary function.

A comparison of the post-fusion outcome of patients with early-onset scoliosis treated with traditional and magnetically controlled growing rods

AIMS

The aim of this study was to compare the clinical and radiological outcomes of patients with early-onset scoliosis (EOS), who had undergone spinal fusion after distraction-based spinal growth modulation using either traditional growing rods (TGRs) or magnetically controlled growing rods (MCGRs).

METHODS

We undertook a retrospective review of skeletally mature patients who had undergone fusion for an EOS, which had been previously treated using either TGRs or MCGRs. Measured outcomes included sequential coronal T1 to S1 height and major curve (Cobb) angle on plain radiographs and any complications requiring unplanned surgery before final fusion.

RESULTS

We reviewed 43 patients (63% female) with a mean age of 6.4 years (SD 2.6) at the index procedure, and 12.2 years (SD 2.2) at final fusion. Their mean follow-up was 8.1 years (SD 3.4). A total of 16 patients were treated with MCGRs and 27 with TGRs. The mean number of distractions was 7.5 in the MCGR group and ten in the TGR group (p = 0.471). The mean interval between distractions was 3.4 months in the MCGR group and 8.6 months in the TGR group (p < 0.001). The mean Cobb angle had improved by 25.1° in the MCGR group and 23.2° in TGR group (p = 0.664) at final follow-up. The mean coronal T1 to S1 height had increased by 16% in the MCGR group and 32.9% in TGR group (p = 0.001), although the mean T1 to S1 height achieved at final follow-up was similar in both. Unplanned operations were needed in 43.8% of the MCGR group and 51.2% of TGR group (p = 0.422).

CONCLUSION

In this retrospective, single-centre review, there were no significant differences in major curve correction or gain in spinal height at fusion. Although the number of planned procedures were fewer in patients with MCGRs, the rates of implant-related complications needing unplanned revision surgery were similar in the two groups. Cite this article: Bone Joint J 2022;104-B(2):257-264.

The STRYDE limb lengthening nail is susceptible to mechanically assisted crevice corrosion: an analysis of 23 retrieved implants

Background and purpose - We noted several adverse events in patients in whom the first version of the STRYDE limb-lengthening nail (NuVasive Specialized Orthopaedics, San Diego, CA) had been implanted. Pain, osteolysis, periosteal reactions, and cortical hypertrophy at the nail junction were noted. Here, we present the analysis of 23 retrieved STRYDE implants.Materials and methods - We undertook visual inspection of the retrieved nails and screws, mechanical evaluation of the junction, micro-CT analyses, microscopic inspection of the bushing, screws, screw holes, and separated parts of the implants. Positive material identification (PMI) and energy-dispersive X-ray spectroscopy (EDS) were used to analyze the chemical composition. The hardness of the material was also investigated.Results - 20/23 retrieved nails had visible signs of corrosion, i.e., discoloration at the telescopic junction. Micro-CT verified corrosion attacks in 12/12 scanned bushings. Corrosion, predominantly mechanically assisted crevice corrosion, was observed at the locking screws and screw holes in 20/23 nails. Biological material inside the nail was observed in addition to oozing from the junction of 2 nails during hardware removal, which was experimentally reproducible. Notably, the mechanical construction of the bushing changed from PRECICE P2 to STRYDE nails.Interpretation - STRYDE nails are not hermetically sealed, and liquid can pass the bushing. Biodur 108 itself is corrosion resistant; however, mechanically assisted crevice corrosion of the bushing, locking screws, and screw holes may be aggravated due to manufacturing aiming for increased strength and hardness of the alloy.Observing several adverse events, we recently published a nationwide cross-sectional analysis of all 30 STRYDE limb- lengthening nails (NuVasive, Specialized Orthopedics, San Diego, CA) that were implanted in Denmark (Rölfing et al. 2021a). 27/30 STRYDE nails have now been removed and we present data from metallurgical analysis of 23 of the retrieved implants.

[Nonfusion procedures in pediatric scoliosis]

The treatment of early onset scoliosis (EOS) in children is a complex and demanding challenge in the treatment of spinal deformities. Conservative treatment with physiotherapy is indicated in mild forms with a Cobb angle from 10° and additionally a corset treatment with a Cobb angle of more than 20°. After exhaustion of the conservative measures or a progression of spinal scoliosis of 10° or deformities of more than 35°, a surgical approach should be considered in order to prevent respiratory insufficiency as well as severe postural and thoracic deformities. In situations where growth is still ongoing fusion operations can lead to stunted growth, a crankshaft phenomenon or degeneration of alignment. Meaningful alternatives to a fusion are so-called growing rods as a distraction-based nonfusion technique, e.g. traditional growing rods (TGR) and magnetically controlled growing rods (MCGR) or as a further method a vertical expandable prosthetic titanium rib (VEPTR) device. The advantages and disadvantages of each operative procedure must be considered with respect to the risk profile of each patient and the experience of the surgeon in order to guarantee the best possible treatment.

Understanding the implant performance of magnetically controlled growing spine rods: a review article

PURPOSE

Early-Onset Scoliosis (EOS) (defined as a curvature of the spine ≥ 10° with onset before 10 years of age) if not properly treated, can lead to increased morbidity and mortality. Traditionally Growing Rods (TGRs), implants fixated to the spine and extended every 6-8 months by surgery, are considered the gold standard, but Magnetically Controlled Growing Rods (MCGRs) avoid multiple surgeries. While the potential benefit of outpatient distraction procedure with MCGR is huge, concerns still remain about its risks, up to the release of a Medical Device Alert (MDA) by the Medicines and Healthcare Regulatory Agency (MHRA) advising not to implant MCGRs until further notice. The aim of this literature review is to (1) give an overview on the use of MCGRs and (2) identify what is currently understood about the surgical, implant and patient factors associated with the use of MCGRs.

METHODS

Systematic literature review.

RESULTS

Surgical factors such as use of single rod configuration or incorrect rod contouring might affect early failure of MCGRs. Patient's older age and higher BMI are correlated with rod slippage. Wear debris and distraction mechanism failure may result from implant design and iteration.

CONCLUSION

Despite the complications reported, this technology still offers one of the best solutions to spine surgeons dealing with severe EOS. Lowering the complication rate by identifying risk factors for failure is possible and further studies in this direction are required. Once the risk factors are well described, some of these can be addressed enabling a safer use of MCGRs.

Comparison of Magnetically Controlled Growing Rods with Other Distraction-Based Surgical Technologies for Early-Onset Scoliosis: A Systematic Review and Meta-Analysis

BACKGROUND

Severe and progressive early-onset scoliosis (EOS) has a serious prognosis including cardiopulmonary compromise. Growth-friendly technologies are the current surgical standard of care. Magnetically controlled growing rods (MCGRs) are newer implants with the potential for better quality of life and cost savings; however, they have not been well compared with the traditional distraction-based implants. The objective of this study was to compare the surgical outcomes, complications, metal ion levels, quality-of-life outcomes, and cost of MCGRs with other distraction-based surgical technologies for the treatment of EOS.

METHODS

The MEDLINE, Embase, and Web of Science databases were searched. Record screening and data abstraction were completed in duplicate. Summary outcomes were calculated in a meta-analysis, if heterogeneity was appropriate, using a fixed-effects model.

RESULTS

This systematic review and meta-analysis included 18 studies. MCGRs were as clinically effective as other distraction-based technologies, with no significant difference in the Cobb angle at the latest follow-up (mean difference [MD], 1.20°; 95% confidence interval [CI], -1.80° to 4.20°; p = 0.43) and a significantly lower complication rate (odds ratio, 0.42; 95% CI, 0.25 to 0.71; p = 0.001). Quality of life measured using the EOSQ-24 (24-Item Early-Onset Scoliosis Questionnaire) was better in the MCGR group compared with other technologies (MD, 2.18; 95% CI, 0.40 to 3.95; p = 0.02). Serum titanium levels were 2.98 ng/mL (95% CI, 1.41 to 4.55 ng/mL; p = 0.0002) greater in patients with MCGRs, but the clinical impact is unclear. MCGRs had greater cost for the device and insertion but became cost-neutral or cost-effective compared with other technologies by 4 years postoperatively.

CONCLUSIONS

MCGRs are clinically equivalent and cost-effective in the long term compared with other distraction-based technologies for the treatment of EOS.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Distraction-to-stall Versus Targeted Distraction in Magnetically Controlled Growing Rods

BACKGROUND

Consensus is lacking regarding the lengthening procedures in magnetically controlled growing rods (MCGR), and no studies have compared the outcome between different distraction principles. The purpose of the present study was to compare distraction-to-stall with targeted distraction and identify variables associated with achieved distraction.

METHODS

We performed a 2-center retrospective study of all children treated with MCGR from November 2013 to January 2019, having a minimum of 1-year follow-up and undergoing a minimum of 3 distractions. Exclusion criteria were single-rod constructs and conversion cases. In group 1 (21 patients), we used a distraction-to-stall (maximum force) principle where each rod was lengthened until the internal magnetic driver stopped (clunking). In group 2 (18 patients), we used a targeted distraction principle, where the desired distraction was entered the remote control before distraction. In both groups we aimed for maximal distraction and curve correction at index surgery. Achieved distraction was measured on calibrated radiographs and compared between the 2 groups using a linear mixed effects model. Univariate and multivariate analyses were performed to identify variables associated with achieved distraction within the first year.

RESULTS

Mean age at surgery was 9.5±2.0 years. Etiology of the deformity was congenital/structural (n=7), neuromuscular (n=9), syndromic (n=3), or idiopathic (n=20). Demographics and preoperative characteristics including spinal height (T1T12 and T1S1) did not differ significantly between the groups (P≥0.13). Time interval between distractions were mean 18 days (95% confidence interval: 10-25) shorter in group 1. Implant-related complications occurred in 10/39 patients, 5 in each group. We found no difference in achieved distraction between the groups in the linear mixed effects model. In the multivariate analysis, preoperative major curve angle was the only independent variable associated with achieved distraction.

CONCLUSIONS

In 2 comparable and consecutive cohorts of patients treated with MCGR, we found no difference in achieved distraction between a distraction-to-stall and a targeted distraction principle. Preoperative major curve angle was the only independent predictor of achieved distraction.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Contouring the magnetically controlled growing rods: impact on expansion capacity and proximal junctional kyphosis

OBJECTIVE

To quantitatively determine the relationship between the contouring of the magnetically controlled growing rods (MCGR), their expansion capacity and the risk of developing proximal junctional kyphosis in early onset scoliosis (EOS). MCGRs allow gradual expansion and correction of the spinal deformity in EOS while reducing the need for repeated surgeries. As the expansion of the MCGRs is controlled externally, several factors can impact the discrepancy between the intended and actual expansions of the rods. The expansion capacity of the growing rods as a function of the expanded length has been tested in experimental setups; however, no study has evaluated the role of contouring of the MCGRs on its function and long-term surgical outcome.

METHODS

A total of 25 EOS patients, a total of 48 MCGRs, with right thoracic curves, were studied retrospectively. All patients had two view spinal radiographs at pre-operative, after MCGR implantation, and after 6 lengthening visits. The first post-operative radiographs were used to calculate the 3D contour of the MCGR at the proximal end. 2D ultrasound images before and after lengthening visits were used to measure the rod lengthening at each visit. The relationship between the increase in the rod length and rod curvature was determined. Finally, the rod curvature was correlated to the changes in proximal junctional kyphosis (PJK) angle between the pre-operative and the most recent follow-up, i.e., after 6 visits.

RESULTS

The average rod 3D angle at the proximal end was 13.5° ± 9.7° [0°-37.2°]. The overall increased length after six lengthening visits for the rod at the concave side was 18.8 mm and at the convex side was 16.9 mm. 62% of the patients with a contoured rod at the proximal end developed a PJK exceeding 10° whereas in patients with a straight rod PJK occurred in 9.1%.

CONCLUSIONS

Contouring the MCGR impacts both the mechanics of the rod expansion and the prevalence of PJK in EOS patient population.

Magnetic Controlled Growth Rods in the Treatment of Scoliosis: Safety, Efficacy and Patient Selection

Early-onset scoliosis is defined as a spinal curvature greater than 10° in children prior to 10 years of age. Untreated EOS may lead to progressively severe spinal deformity, impaired pulmonary development, restrictive lung disease, and both increased morbidity and mortality. Limitations of established conservative treatments include inability to correct severe deformity, as well as challenges with compliance when casting and bracing is applied. In addition, surgical treatment in the form of traditional growing rods requires regular surgical lengthenings and is associated with complications inherent with repeated invasive procedures and exposure to general anesthesia. MAGEC is an evolving magnetically controlled growing rod system for the treatment of EOS. After initial implantation, lengthening is achieved non-invasively by using magnetic external remote control. MAGEC offers the potential to control moderate and severe EOS, while avoiding repeated surgical procedures and associated complications. In this review, we examine the results from clinical, radiological and explant studies following the use of MAGEC, in the context of other established and emerging treatments for EOS.