Minimum 2-Year Experience with Magnetically Controlled Growing Rods for the Treatment of Early-Onset Scoliosis: A Systematic Review

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.

Clinical and radiological results of final fusion in patients who underwent lengthening with magnetically controlled growing rods. About 66 patients with a mean follow-up of 5 years

PURPOSE

The aim of this study was to evaluate the effects of definitive arthrodesis on frontal and sagittal spine balance in EOS patients treated with MCGR, as well as the complications associated with this procedure and the outcome at last follow-up.

METHODS

This was a multicentre study in 10 French centres. All patients who underwent posterior spinal arthrodesis after completion of MCGR treatment, regardless of age, etiology of scoliosis between 2011 and 2022, were included.

RESULTS

A total of 66 patients who had a final fusion after the lengthening programme were included in the study. The mean follow-up time was 5.5 ± 1.7 years (range: 2.1-9). The mean follow-up time after arthrodesis was 24 ± 18 months (range: 3-68) and the mean age at arthrodesis was 13.5 ± 1.5 years (range: 9.5-17). The main and secondary curves were significantly (p < 0.005 and p = 0.03) improved by arthrodesis (16.4° and 9° respectively) and stabilised at the last follow-up. The T1-T12 and T1-S1 distances increased by 8.4 mm and 14 mm with spinal fusion, with no significant difference (p = 0.096 and p = 0.068). There was no significant improvement in the rest of the parameters with arthrodesis, nor was there any significant deterioration at last follow-up. After final fusion, there were a total of 24 complications in 18 patients (27.3%) that routinely led to repeat surgery.

CONCLUSION

Final fusion after MCGR provides satisfactory additional correction of the main and secondary curves and a moderate increase in the T1-T12 distance but has no impact on sagittal balance and other radiological parameters. The post-operative complication rate is particularly high in patients at risk of complications.

LEVEL OF EVIDENCE

Level 4.

Clinical and radiographic evolution of graduate patients treated with magnetically controlled growing rods: results of a French multicentre study of 90 patients

PURPOSE

The purpose of this study was to investigate patients with early-onset scoliosis (EOS) who completed their electromagnetic lengthening rod program to assess the demographics of this population and to analyze the evolution of clinical and radiological parameters and the occurrence of complications.

METHODS

This was a multicenter study with 10 French centers. We collected all patients with EOS who had undergone electromagnetic lengthening between 2011 and 2022. They had to have reached the end of the procedure (graduate).

RESULTS

A total of 90 graduate patients were included. The mean follow-up time over the entire period was 66 months (25.3-109). Of these, only 66 patients (73.3%) underwent definitive spinal arthrodesis at the end of the lengthening phase, whereas 24 patients (26.7%) kept their hardware in situ with a mean follow-up time from the last lengthening of 25 months (3-68). Patients had an average of 2.6 surgeries (1-5) over the entire follow-up. Patients had an average of 7.9 lengthenings for a mean total lengthening of 26.9 mm (4-75). Analysis of the radiological parameters showed a percentage reduction in the main curve of 12 to 40%, depending on the etiology, with an average reduction of 73-44°, and an average thoracic height of 210 mm (171-214) for an average improvement of 31 mm (23-43). There was no significant difference in the sagittal parameters. During the lengthening phase, there were a total of 56 complications in 43 patients (43.9%; n = 56/98), of which 39 in 28 patients (28.6%) resulted in unplanned surgery. In the graduate patients, there were a total of 26 complications in 20 patients (22.2%), all of which resulted in unscheduled surgery.

CONCLUSION

MCGR, allow to decrease the number of surgeries, to progressively improve the scoliotic deformity and to reach a satisfactory thoracic height at the price of an important complication rate linked in particular to the complexity of the management of patients with an EOS.

LEVEL OF EVIDENCE II

Minimum 3-year experience with vertebral body tethering for treating scoliosis: A systematic review and single-arm meta-analysis

PURPOSE

Over the past 12 years, vertebral body tethering (VBT) has been gradually promoted for treating scoliosis, but there are few published studies, with only short-term follow-up. This study aimed to systematically review VBT efficacy and safety for treating scoliosis.

METHODS

PubMed, Web of Science, Embase, and the Cochrane Library were searched for studies on VBT treatment of scoliosis published up to November 2021. Two researchers independently screened the literature, extracted data, and assessed the risk of bias in included studies. Data on clinical efficacy, unplanned reoperations, and complications were extracted. The meta-analysis was performed with R 4.1.0.

RESULTS

Twenty-six studies involving 1045 patients were included in the meta-analysis. The correction rate of major curve immediately post-operation was 46.6% ± 13.8% (16%-69%) and that at final follow-up was 53.2% ± 17.9% (16%-79%). The single-arm meta-analysis results of all included studies showed that VBT was effective in general. The overall clinical success rate was 73.02% (95% confidence interval [CI]: 68.31%-78.05%). The pooled overall unplanned reoperation rate was 8.66% (95% CI: 5.53%-13.31%). The overall incidence rate of complications was 36.8% (95% CI: 23.9%-49.7%). The subgroup analysis based on follow-up time indicated that patients with follow-up time >36 months had increased clinical success rate, unplanned reoperation rate, and incidence rate of complications compared with those with <36 months' follow-up time. The preliminary results showed that after 36 months of follow-up, only 7.17% (95% CI: 4.81%-10.55%) of patients required posterior spinal fusion (PSF) surgery and nearly 93% of patients avoided spinal fusion surgeries.

CONCLUSIONS

The current evidence from at least 3-year follow-up in different countries indicates that VBT is an effective surgical approach for treating scoliosis, with 73.88% of patients achieving clinical success. Nevertheless, about one in seven patients (15.8%) required unplanned reoperations, but only 7.17% required PSF. About half (52.17%) of the patients experienced complications. Due to the limitation of the study number and quality, our conclusion may be biased and requires verification by further studies with longer follow-up times.

The Efficacy of Single-Stage Correction by Posterior Approach for Neglected Congenital Scoliosis: Comparative Analysis According to the Age of Surgical Intervention

Background: A single-stage correction for congenital scoliosis through a posterior-only approach is a commonly used surgical technique. However, there are few studies on the surgical treatment effect of posterior single-stage correction in patients with neglected congenital scoliosis. Methods: Patients who underwent a single-stage posterior correction for congenital scoliosis with a minimum follow-up of 2 years were divided into three groups based on age: Group A (7−11 years), B (12−18 years) and C (>18 years). A comparison of surgical, radiological, and clinical outcomes was performed for three groups. Results: The Cobb angle changed form 75 ± 18° to 37 ± 18° with a correction rate of 53%. Group A showed a significantly higher correction rate than Group B and C (all p < 0.001). The amount of blood loss in Groups B and C was significantly larger than that of Group A (p = 0.015). Pulmonary complications were significantly higher in Group C (p = 0.007). Conclusions: A single-stage correction with pedicle screws through a posterior-only approach achieved a significant correction with improved outcomes, even in neglected cases. However, the early correction for younger patients was still more beneficial in terms of bleeding loss, complications, and flexible curve correction.

Is there an indication for surgery in patients with spinal deformities? - A critical appraisal

Background

High-quality evidence exists to support physiotherapy and brace treatment for scoliosis and other spinal deformities. However, according to previous systematic reviews, it seems that no evidence exists for surgery. Nevertheless, the number of research articles focussing on spinal surgery highly exceeds the number of articles focussing on conservative treatment.

Objective

The purpose of this study is to conduct an updated search for systematic reviews providing high-quality evidence for spinal surgery in patients with spinal deformities.

Method

A narrative review including PubMed and the Cochrane database was conducted on April 12, 2020, with the following search terms: (1) spinal deformities, surgery, systematic review and outcome; (2) kyphosis, surgery, systematic review and outcome; (3) Scheuermann's disease, surgery, systematic review and outcome, and (4) scoliosis, surgery, systematic review and outcome.

Results

No reviews containing prospective controlled or randomised controlled studies were found providing evidence for surgery.

Conclusions

A general indication for spine surgery just based on the Cobb angle is not given. In view of the long-term unknown variables and the possible long-term complications of such treatment, a surgical indication for patients with spinal deformities must be reviewed on an individual basis and considered carefully. A current systematic review appears necessary in order to be able to draw final conclusions on the indication for surgery in patients with spinal deformities.

Clinical implications

In view of the increasing number of surgeons with an affiliation to industry, the indication for surgery needs to be given by independent conservative specialists for spinal deformities in order to provide an objective recommendation.

Diagnosis and treatment of congenital scoliosis

Background: Congenital scoliosis is caused by anomalies of the vertebra, such as hemivertebra or unsegmented bar, which result in asymmetric growth of the spine. The disruption of vertebra development during embryogenesis may be accompanied by other congenital multi-organ anomalies. The progression of the scoliotic curve may also hinder the development of other organs.Current Concepts: Hemivertebra excision and short spinal fusion have demonstrated favorable outcomes. However, the need for spinal growth and lung development has led to new treatment modalities. Growth-friendly surgeries, such as with a growing rod or vertical expandable rib-based distraction device, have demonstrated good results with curve correction while maintaining spinal growth. Although the outcome of conservative treatment for congenital scoliosis is questionable, casting may be effective as a “time-buying strategy” to delay the need for surgery.Discussion and Conclusion: It is essential to decide on a treatment plan considering the progression of the curve and growth of the spine and lungs through an individualized approach.

A biomechanical study on the effect of lengthening magnitude on spine off-loading in magnetically controlled growing rod surgery: Implications on lengthening frequency

Purpose: To assess whether the magnitude of lengthening in magnetically controlled growing rod (MCGR) surgeries has an immediate or delayed effect on spinal off-loading. Methods: 9 whole porcine spines were instrumented using two standard MCGRs from T9 to L5. Static compression testing using a mechanical testing system (MTS) was performed at three MCGR lengthening stages (0 mm, 2 mm, and 6 mm) in each spine. At each stage, five cycles of compression at 175N with 25 min of relaxation was carried out. Off-loading was derived by comparing the load sustained by the spine with force applied by the MTS to the spine. Micro-CT imaging was subsequently performed. Results: The mean load sustained by the vertebral body before lengthening was 39.69N, and immediately after lengthening was 25.12N and 19.91N at 2 mm and 6 mm lengthening, respectively; decreasing to 10.07N, 8.31N, and 8.17N after 25 minutes of relaxation, at 0 mm, 2 mm, and 6 mm lengthening stages, respectively. There was no significant difference in off-loading between 2 mm and 6 mm lengthening stages, either instantaneously (p = 0.395) or after viscoelastic relaxation (p = 0.958). CT images showed fractures/separations at the level of pedicle screws in six spines and in the vertebral body's growth zone in five spines after 6 mm MCGR lengthening. Conclusion: This study demonstrated MCGRs cause significant off-loading of the spine leading to stress shielding. 6 mm of lengthening caused tissue damage and microfractures in some spines. There was no significant difference in spine off-loading between 2 mm and 6 mm MCGR lengthening, either immediately after lengthening or after viscoelastic relaxation.

Incidence and Surgery Rate of Idiopathic Scoliosis: A Nationwide Database Study

Idiopathic scoliosis is the most common cause of three-dimensional deformities of the spine. Most of the previous studies have been cross-sectional studies to estimate the prevalence in the general population. An age-matched, population-based study is performed using nationwide databases between 2011 and 2015. The incidence rates of idiopathic scoliosis by age group, sex, and region are identified. We also investigate the pattern of medical institution use and the surgery rate of patients with idiopathic scoliosis. Our results show that a total of 268,372 patients were diagnosed with idiopathic scoliosis. The overall incidence was 0.497%, and the incidence for females was 1.44 times higher than for males. By age group, the incidence of adolescent idiopathic scoliosis in patients aged 10–14 years was 0.821% compared to 0.029%, 0.192%, and 0.709% for those patients aged 0–2, 3–9, and 15–19 years, respectively. Both male and female urban populations had higher incidences than rural populations with no age differences at diagnosis. Survival analysis confirmed that 0.7% of diagnosed patients underwent surgical treatment within five years. Understanding the epidemiology of idiopathic scoliosis is helpful in diagnosing high risk patients and monitoring surgical interventions.

Cross-Cultural Adaptation and Validation of the Persian Version of the 24-Item Early-Onset Scoliosis Questionnaire

Study Design

Cross-sectional study.

Purpose

To translate and culturally adapt the original English version of the 24-item Early-Onset Scoliosis Questionnaire (EOSQ-24) to the Persian language as well as assess its reliability and validity.

Overview of Literature

Early-onset scoliosis (EOS) patients with progressive curves require active treatments, such as serial elongation–derotation–flexion casting, bracing, and surgery, which are stressful and expensive. In order to evaluate the impact of EOS and its treatment strategies, it is important to consider the patients and their parents’ quality of life as the clinical and radiological parameters. The EOSQ-24 is a parent-based measure that evaluates the health-related quality of life of patients with EOS and their caregivers/parents. Similar to other widely used questionnaires, EOSQ-24 needs to be translated into other languages to make it usable in populations from different cultures and societies.

Methods

We evaluated the translation and back translation of the EOSQ-24 and made the required revisions as per the analysis performed by the expert committee and an international guideline to adapt it for use in this study. Thereafter, we recruited 100 EOS patients in order to evaluate its reliability and validity. The reliability was assessed with internal consistency. Convergent validity was assessed by comparing the scores of the EOSQ-24 and the 22-item Scoliosis Research Society Questionnaire (SRS-22r). Finally, the known groups validity was assessed as per patient’s sex, curve magnitude, and treatment type.

Results

The Persian EOSQ-24 demonstrated very good internal consistency (Cronbach’s α=0.88). All the items had an acceptable corrected item-total correlation (>0.3). Further, the EOSQ-24 and the SRS-22r scores (p<0.001) were significantly correlated. The EOSQ-24 could discriminate patients with different curve magnitudes.

Conclusions

The Persian EOSQ-24 can serve as a disease-specific instrument with strong validity and reliability in the evaluation of EOS patients. Its applicability in other Persian-speaking countries and regions of the world needs to be investigated further.

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.

Sonography of Magnetically Controlled Growing Rods: A Quality Initiative in the Creation of a Multidisciplinary Clinic

Objective:

The MAGEC (Magnetic Expansion Control) rods were introduced to a medical institution in 2015. The rod expansion procedures were initially evaluated with radiographs. The staff undertook a quality initiative to reduce radiation exposure by utilizing sonography.

Material and Methods:

The radiation dose for a typical visit was measured by examining DICOM imaging data, stored in PACS. Imaging visit time was determined from the difference between times of first radiograph/sonogram before distraction to last radiograph/sonogram after distraction.

Results:

The 21 patients (8 male, 13 female) were an average age of 11.4 ± 2.82 years (age at implant = 7.5 ± 1.94) when evaluated. The average length of time for a radiographic visit was 40.7 ± 20.7 minutes, whereas a sonography visit was 10.7 ± 3.7 minutes. Radiation dose per study visit prior to the introduction of the MAGEC clinic was 0.42 ± 0.39 mSv. Given an ideal patient schedule, the MAGEC clinic could reduce radiation dose by 1.3 to 2.5 mSv annually, with 95% confidence.

Conclusion:

This quality improvement study demonstrated a reduction in radiation exposure and imaging time. The added benefits were providing a successful multidisciplinary imaging clinic and creation of a new exam that aligned with the “ultrasound first” initiative.