Early experience of MAGEC magnetic growing rods in the treatment of early onset scoliosis

Elevated blood metal ion levels in patients undergoing instrumented spinal surgery: a systematic review and meta-analysis

BACKGROUND CONTEXT

Elevated blood metal levels have been reported in patients after spinal surgery using metallic implants. Although some studies have suggested an association between heightened blood metal concentrations and potential adverse effects, estimates of the incidence of abnormal metal levels after spinal surgery have been inconsistent.

PURPOSE

The aims of this systematic review and meta-analysis were to assess: (1) mean differences in blood metal ion levels between patients undergoing spinal fusion surgery and healthy controls, (2) odds of elevated blood metal ion levels after surgery compared to presurgery levels, and (3) pooled incidence of elevated blood metal ions overall and by metal type.

STUDY DESIGN

Systematic review and meta-analysis.

PATIENTS SAMPLE

The patient sample included 613 patients from 11 studies who underwent spinal surgery instrumentation.

OUTCOME MEASURES

Blood metal ion concentrations and the incidence of patients with elevated metal levels compared with in those the control group.

METHODS

A comprehensive search was conducted in PubMed, EMBASE, Scopus, and Cochrane Library to identify studies reporting blood metal ion levels after spinal fusion surgery. Mean differences (MD), odds ratios (OR), and incidence rates were pooled using random effects models. Heterogeneity was assessed using I2 statistics, and fixed-effects models were used if no heterogeneity was detected. Detailed statistical analysis was performed using the Review Manager version 5.4 software.

RESULTS

The analysis included 11 studies, with a total of 613 patients. Mean blood metal ion levels were significantly higher after spinal fusion surgery (MD 0.56, 95% CI 0.17-0.96; I2=86%). Specifically, titanium levels were significantly elevated (MD 0.81, 95% CI 0.32-1.30; I2=47%). The odds of elevated blood metal ions were higher after surgery (OR 8.17, 95% CI 3.38-19.72; I2=41%), primarily driven by chromium (OR 23.50, 95% CI 5.56-99.31; I2=30%). The incidence of elevated chromium levels was found to be 66.98% (95% CI 42.31-91.65).

CONCLUSION

In conclusion, blood metal ion levels, particularly titanium and chromium, were significantly increased after spinal fusion surgery compared to presurgery levels and healthy controls. Approximately 70% of the patients exhibited elevated blood levels of chromium and titanium.

Is posterior vertebral arthrodesis at the end of the electromagnetic rod lengthening program necessary for all patients? Comparative analysis of sixty six patients who underwent definitive spinal arthrodesis and twenty four patients with in situ lengthening rods

PURPOSE

Magnetically controlled growing rods (MCGR) should be removed or changed at most two years after their implantation in the treatment of patients with early-onset scoliosis (EOS) (Safety notice July 2021). However, in the face of patients at high risk of intraoperative complications and relying on the principle of auto-fusion of the spine, some surgeons would prefer a more wait-and-see attitude. The aim of this study was to report on patients who did not undergo final fusion at the end of the lengthening program with MCGR and to compare them with those who did.

METHODS

This was a multicenter study with ten centres. We collected all graduate patients with EOS who had received MCGR between 2011 and 2022.

RESULTS

A total of 66 patients had final fusion at the end of the lengthening program and 24 patients kept MCGRs in situ. The mean total follow-up time was 66 months (range, 25.3-109), and the mean follow-up time after final lengthening was 24.9 months (range, 3-67.7). Regarding the main curve and thoracic height, there was no significant difference in the percentage of correction over the whole follow-up between the two groups (p = 0.099, p = 0.176) although there was a significant difference between the end of lengthening and the last follow-up (p < 0.001). After completion of the lengthening program, 18 patients who had final fusion developed 24 of the 26 recorded complications (92.3%).

CONCLUSION

Contrary to the manufacturer's published safety notice, not all patients systematically benefited from the removal of the MCGRs. Although arthrodesis significantly improved the scoliotic deformity, no significant difference was found in terms of radiographic outcome between patients who underwent spinal fusion and those who kept the MCGRs in situ.

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.

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

Autofusion With Magnetically Controlled Growing Rods: A Case Report

Magnetically controlled growing rods (MCGRs) are an effective alternative to traditional growing rods (TGRs) in the treatment of early-onset scoliosis (EOS), with comparable deformity correction despite fewer planned reoperations. This case report presents a unique case of autofusion in a patient with tetraplegic cerebral palsy, thoracic myelomeningocele, and EOS who was treated with dual MCGR instrumentation and underwent serial lengthening procedures for four years. We detail the operative and radiographic findings in a novel case of autofusion encountered after MCGR placement to treat EOS. An eight-year-old female with tetraplegic cerebral palsy causing a 94° right thoracic neuromuscular scoliosis was treated with dual MCGRs; she then underwent serial lengthenings every four months. At 12 years of age, during MCGR explantation and posterior spinal fusion, dense heterotopic autofusion was encountered around the MCGR instrumentation, limiting further deformity correction. The benefits of MCGRs make them an appealing alternative to TGRs for the treatment of EOS. Although the theoretical risk of autofusion in MCGRs is low, recent case reports propose autofusion as a possible reason for MCGRs' failure to lengthen.

Outcomes Evaluating Quality of Life and Their Measurement Properties in Early-onset Scoliosis: A Systematic Review

INTRODUCTION

Early-onset scoliosis (EOS) is a spinal deformity affecting children under the age of 10. Understanding the impact of EOS on quality of life can be achieved through appropriate patient/carer-reported outcome measures (PROMs). The aim of this systematic review was to identify, evaluate and summarize the evidence for the measurement properties of health-related quality of life (HR-QoL) outcome measures in the EOS population.

METHODS

A 2-stage search methodology was conducted across the PubMed, MEDLINE, EMBASE, EMCARE, PsychINFO, and CINAHL databases. Search 1 identified PROMs used to evaluate the quality of life in EOS, and search 2 identified studies of the measurement properties of these PROMs. Two reviewers performed searching, study screening and selection and assessed studies for risk of bias using the Consensus-based Standards for the selection of health Measurement INstruments (COSMIN) Risk of Bias checklist. One reviewer performed data extraction. Evidence for each measurement property per PROM was summarized and evaluated using a modified GRADE approach.

RESULTS

Search 1 identified 19 (10 disease-specific, 9 generic) PROMs that have been used to assess HR-QoL or a relevant domain in the EOS population. Search 2 identified only one PROM (the 24-item Early-Onset Scoliosis Questionnaire, EOSQ) with eligible studies (n=4) evaluating measurement properties. There is low-quality evidence for sufficient content validity, very low-quality evidence for sufficient reliability and low-quality evidence for sufficient criterion validity, specifically regarding the pulmonary function domain) of the EOSQ. Construct validity and responsiveness were rated as indeterminate. There were no studies on measurement error.

CONCLUSIONS

Our search strategy found that measurement properties have only been evaluated for one PROM, the EOSQ. There is low-quality evidence for sufficient measurement properties for the EOSQ in patients under the age of 10 with EOS. Further research is needed to improve the quality of evidence for EOSQ measurement properties and investigate other PROMs in this population.

LEVEL OF EVIDENCE

Level II.

Trends in the Utilization of Implants in Index Procedures for Early Onset Scoliosis From the Pediatric Spine Study Group

INTRODUCTION

Because of the relative rarity of Early Onset Scoliosis (EOS) cases, patient registries were developed to combine clinical information from multiple institutions to maximize patient care and outcomes. This study examines the history and trends regarding the use of growth-friendly devices for index surgical procedures in EOS patients within the Pediatric Spine Study Group database.

METHODS

All index growth-friendly implants were queried from registry inception until October 2020. EOS etiology, device/implant type, and geographic area/institution for each procedure were recorded.

RESULTS

From 1994 to 2020, 2786 patients underwent index surgery at a mean age of 6.2±2.9 years. There were 908 traditional growing rods (TGR) (32.3%), 922 vertical expandable prosthetic titanium rib devices (VEPTR) (33.1%), 5 hybrid VEPTR/TGR (0.18%), and 951 magnetically controlled growing rods (MCGR) (34.2%) index implants. Fifty-six different institutions reported an index implant, and 5 accounted for 823 (30%) of the cases during the study period. Institutions in the Northeast accounted for more index implants than other regions of the United States. There was a 40% increase in index implant insertions annually when comparing 1994 (3 implants/1 center) to 2018 (234 implants/56 centers), ( P <0.001). Beginning in 2009, there was a 90.9% decrease in the number of TGR/VEPTR procedures (2009: 156 implants/32 centers; 2019: 22 implants/49 centers P =0.001), and a 479% increase in MCGR (2009: 1 implant/1 center; 2018: 197 implants/34 centers ( P =0.005). The overall number of growth-friendly index procedures performed in 2019 (150/49 centers) decreased 34.5% when compared to 2018 (234/48 centers).

CONCLUSION

The number of growth-friendly implants reported in the Pediatric Spine Study Group registry as the initial surgical management of EOS increased markedly over the past 20 years. MCGR is currently the predominant type of device utilized for index surgical procedures by group members, surpassing the use of VEPTR and TGR in 2014. There was a significant decrease in index growth-friendly procedures in 2019 compared to 2018.

LEVEL OF EVIDENCE

Level IV.

Comparison of surgical interventions for the treatment of early-onset scoliosis: a systematic review and meta-analysis

OBJECTIVE

Several growth-preserving surgical techniques are employed in the management of early-onset scoliosis (EOS). The authors' objective was to compare the use of traditional growing rods (TGRs), magnetically controlled growing rods (MCGRs), Shilla growth guidance techniques, and vertically expanding prosthetic titanium ribs (VEPTRs) for the management of EOS.

METHODS

A systematic review of electronic databases, including Ovid MEDLINE and Cochrane, was performed. Outcomes of interest included correction of Cobb angle, T1-S1 distance, and complication rate, including alignment, hardware failure and infection, and planned and unplanned reoperation rates. The percent changes and 95% CIs were pooled across studies using random-effects meta-analysis.

RESULTS

A total of 67 studies were identified, which included 2021 patients. Of these, 1169 (57.8%) patients underwent operations with TGR, 178 (8.8%) Shilla growth guidance system, 448 (22.2%) MCGR, and 226 (11.1%) VEPTR system. The mean ± SD age of the cohort was 6.9 ± 1.2 years. The authors found that the Shilla technique provided the most significant improvement in coronal Cobb angle immediately after surgery (mean [95% CI] 64.3% [61.4%-67.2%]), whereas VEPTR (27.6% [22.7%-33.6%]) performed significantly worse. VEPTR also performed significantly worse than the other techniques at final follow-up. The techniques also provided comparable gains in T1-S1 height immediately postoperatively (mean [95% CI] 10.7% [8.4%-13.0%]); however, TGR performed better at final follow-up (21.4% [18.7%-24.1%]). Complications were not significantly different among the patients who underwent the Shilla, TGR, MCGR, and VEPTR techniques, except for the rate of infections. The TGR technique had the lowest rate of unplanned reoperations (mean [95% CI] 15% [10%-23%] vs 24% [19%-29%]) but the highest number of planned reoperations per patient (5.31 [4.83-5.82]). The overall certainty was also low, with a high risk of bias across studies.

CONCLUSIONS

This analysis suggested that the Shilla technique was associated with a greater early coronal Cobb angle correction, whereas use of VEPTR was associated with a lower correction rate at any time point. TGR offered the most significant height gain at final follow-up. The complication rates were comparable across all surgical techniques. The optimal surgical approach should be tailored to individual patients, taking into consideration the strengths and limitations of each option.

Magnetically controlled growing rods in the management of early onset scoliosis: a systematic review

Background

Early onset scoliosis (EOS) presents in patients younger than 10 years. Magnetically controlled growing rods (MCGR) were developed as an outpatient distraction system for EOS, allowing to avoid multiple surgeries. This systematic review investigated the efficacy and feasibility of MCGR in EOS.

Methods

This systematic review was conducted according to the PRISMA guidelines. PubMed, Google scholar, Embase, and Scopus were accessed in May 2022. All the clinical trials which investigate the role of MCGR for early onset scoliosis were accessed. Only studies reporting data in patients younger than 10 years with a preoperative Cobb Angle greater than 40° were eligible. The following data was extracted at baseline and at last follow-up: mean kyphosis angle, overall mean Cobb angle, mean T1–S1 length. Data from complication were also collected.

Results

Data from 23 clinical studies (504 patients) were included in the present study. 56% (282 of 504) were females. The average length of the follow-up was 28.9 ± 16.0 months. The mean age of the patients was 8.7 ± 1.9 years old. The mean BMI was 17.7 ± 7.6 kg/m². The mean kyphosis angle had reduced by the last follow-up (P = 0.04), as did the overall mean Cobb angle (P < 0.0001), while the overall T1–S1 length increased (P = 0.0002). Implant-associated complications, followed by spinal alignment failure, wound healing ailments, pulmonary complications, progressive trunk stiffness, persistent back pain, and fracture.

Conclusion

The management of EOS remains challenging. The current evidence indicates that MCGR may be effective to distract the spine and model the curve in EOS.

Developments, Focuses, and Trends in Early-Onset Scoliosis From 2005 to 2020: A Systematic Bibliometric Analysis

OBJECTIVE

Although several studies have been reported on early-onset scoliosis (EOS), a bibliometric analysis is still lacking. A systematic bibliometric analysis will enable researchers to understand the scope of the research topics, identify research focuses and key literature, and predict future research directions.

METHODS

Literature data were retrieved from the Web of Science Core Collection database. The Web of Science Results Analysis and Citation Report were used to analyze the reported studies in different views. CiteSpace and VOSviewer were used for further analysis, including a cooperation network analysis of the authors, institutions, countries and/or regions, discipline and journal analysis, reference co-citation analysis, and keyword co-occurrence analysis.

RESULTS

The final analysis included 674 relevant studies reported from 2005 to 2020. During the study period, the field of EOS has expanded rapidly. Multiple cooperation was found among the authors, institutions, and countries and/or regions, with some making great contributions. The results of the reference co-citation analysis showed that the studies had several main focuses, including the growing rod (GR), magnetically controlled GR, an EOS 24-item questionnaire, and a growth evaluation.

CONCLUSIONS

From 2005 to 2020, surgical treatment has remained the focus of research in the EOS field. The magnetically controlled GR is the latest research focus, which might become more comprehensive in the future. The Gr has remained the most popular topic, and potential new surgical techniques might require improvement to become the favored techniques. In addition, assessing the health-related quality of life and growth parameters of patients with EOS have become a popular topic.

Outcomes evaluating quality of life and their measurement properties in early-onset scoliosis: protocol for a systematic review

INTRODUCTION

Early-onset scoliosis (EOS) is a rare spinal deformity affecting children under the age of 10. Both the condition and its treatment have associated morbidity and can impact quality of life. Understanding this impact can be achieved by using appropriate patient-reported and/or carer-reported outcome measures. The aim of the review described in this protocol is to evaluate the evidence on measurement properties relevant to health-related quality of life outcomes in the EOS population. The focus will be on outcome measures relevant to patients undergoing treatment of EOS under the age of 10.

METHODS/ANALYSIS

This protocol is reported in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol and COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) methodology. The MEDLINE, EMBASE, EMCARE, PubMed, PsychINFO and CINAHL databases will be searched using a two-stage search strategy. The first stage will identify measures of HRQoL used in EOS through screening of titles and abstracts. The second stage will assess the measurement properties of those measures identified through screening of full-text articles. The measurement properties of interest are the 'reliability', 'validity' and 'responsiveness' of the instrument. Only English language articles will be considered. Two reviewers will independently review the search results against the eligibility criteria, perform data extraction and assess for risk of bias, with disputes handled by a third reviewer. Data will be quantitatively pooled where possible or reported as a narrative synthesis. The summarised results for each measurement property will be rated against the criteria for good measurement properties following the COSMIN methodology. Two reviewers will assess the body of evidence for each measurement property using modified Grading of Recommendations, Assessment, Development and Evaluation guidelines.

ETHICS AND DISSEMINATION

No ethical approval is required for this review and the results will be submitted for publication in peer-reviewed publications.

PROSPERO REGISTRATION NUMBER

CRD42020219721.

Quality of Life Among Patients with Early-Onset Scoliosis Treated with Magnetically Controlled Growing Rods-Early-Term Results

BACKGROUND

The term "early-onset scoliosis" (EOS) refers to spinal deformities that develop before the age of 10 years. The aim of surgical treatment for EOS is stopping the progression of the curvature, maintaining the correction, ensuring the maximum growth of the vertebrae, and ensuring that the vertebrae remain mobile. Using magnetically controlled growing rods (MCGRs) in the treatment of EOS is intended to protect the patient from the negative effects of repetitive surgeries, increase patient compliance and satisfaction, and increase the speed of return to normal social life. Our aim was to report the early radiological evaluation findings and detect the changes in the quality of life of patients and their parents after the diagnosis of EOS and treatment with MCGRs.

METHODS

We performed a retrospective clinical study (level 4 case series) of 20 patients with a surgical indication for the treatment of EOS. The 20 patients had undergone treatment with MCGRs and lengthening procedures at 3-month intervals from August 2014 to August 2016. The mean patient age at surgery was 7.9 years (range, 4-10 years), and the mean length of follow-up was 14.9 months (range, 6-30 months). The preoperative, early postoperative, and final follow-up radiographs of all patients were obtained. The Cobb angle, thoracic kyphosis, spinal height, thoracic height, sagittal balance, coronal balance, shoulder balance, and pelvic balance were measured from the radiographs. All the patients had undergone preoperative and final follow-up respiratory function tests, and all the patients completed the Early Onset Scoliosis 24-item questionnaire (EOSQ-24). The outcome measures were the Cobb angle, thoracic kyphosis, spinal height, thoracic height, sagittal balance, coronal balance, shoulder balance, and pelvic balance. All the patients had undergone preoperative and final follow-up respiratory function tests, and the parents of every patient completed the Turkish version of the EOSQ-24.

RESULTS

The preoperative, early postoperative and final follow-up mean Cobb angles were 56.6° (range, 38°-93°), 30.5° (range, 13°-80°), and 33.5° (range, 14°-86°), respectively. These findings showed statistically significant improvement in the Cobb angle (P < 0.05). The thoracic height was also significantly increased. The preoperative, early postoperative, and final follow-up mean height was 181 mm (range, 123-224 mm), 200 mm (range, 164-245 mm), and 212 mm (range, 167-248 mm), respectively (P < 0.05). The measurements for spinal height had also increased significantly, with preoperative, early postoperative, and final follow-up values of 219 mm (range, 213-366 mm), 315 mm (range, 260-402 mm), and 338 mm (range, 261-406 mm), respectively (P < 0.05). The thoracic kyphosis measurement was 41° (range, 5°-65°) preoperatively, which had decreased significantly to 32.5° (range, 0°-53°) at the final follow-up (P < 0.05). Our measurements showed no statistically significant differences in the coronal and sagittal balance, pelvic balance, or shoulder balance. No significant differences were found between the preoperative and postoperative respiratory function test results. The assessment of the EOSQ-24 scores had demonstrated significant improvements in the mean scores at the final follow-up (P < 0.05). When different categories in the EOSQ-24 were evaluated separately, no statistically significant differences were found between the preoperative and final follow-up scores for general health, pain and discomfort, respiratory function, movement capability, physical function, or effects on daily life (P > 0.05). However, the exhaustion and energy levels, emotional state, effect of the disease on the parents and patient, and parent satisfaction scores had increased significantly from the preoperative assessment to the final follow-up (P < 0.05). The financial effect had decreased significantly at the final follow-up compared with the preoperative values (P < 0.05). Four patients had developed complications requiring further treatment, and none of the patients had developed infection that required surgical intervention.

CONCLUSIONS

Our study showed that insertion of a MCGR is a safe procedure for treatment of EOS to correct the deformity and improve function in daily life. This method reduces the need for repetitive surgery and the likelihood of complications associated with other treatments. Thus, treatment with MCGRs increases patient satisfaction and facilitates patient compliance.

Magnetically Controlled Growing Rods: Influence on Intraoperative Fluoroscopic Imaging: A Case Report

CASE

A 7-year-old boy with severe congenital scoliosis and impending thoracic insufficiency syndrome underwent uneventful single magnetically controlled growing rod (MCGR) insertion and removal of his ipsilateral rib-based distraction implants at our institution. Intraoperative fluoroscopy imaging revealed an artifactual bend (S-distortion) of the rod actuator after placement. This artifact was eliminated by moving the image intensifier further from the patient.

CONCLUSION

We attributed the S-distortion to influences of magnetic fields within the MCGR actuator onto the image intensifier. Surgeons should be aware of such implications which can lead to misleading imaging artifacts. This is a first reported case of such incident with MCGR.

Management and results of early-onset scoliosis with dual magnetically controlled growing rods: Additional preliminary results of spinal fusion surgery

OBJECTIVES

The aim of this study was to evaluate the clinical and radiographic outcomes and complications of dual magnetically controlled growing rods (MCGRs) in the treatment of early-onset scoliosis (EOS) and to investigate the results of patients with definitive spinal fusion following MCGR.

PATIENTS AND METHODS

A total of 15 patients (7 males, 8 females; mean age: 8.7±1.7 years; range, 6 to 10 years) with EOS who underwent dual MCGR and were prospectively followed between February 2013 and March 2019 were included in this retrospective study. The Cobb angle, thoracic kyphosis, and the length of the spine between T1-T12 and T1-S1 were measured on preoperative, postoperative, and follow-up radiographs. The 24-Item Early-Onset Scoliosis Questionnaire (EOSQ-24) was used to assess the functional outcomes before and after the operation. All complications during the treatment were recorded.

RESULTS

The mean follow-up was 27.8±10.4 (range, 12 to 60) months. The mean curve correction immediately after the index surgery and latest follow-up was 47.6% and 42.4%, respectively (p>0.05). At the last follow-up, there were no significant changes in mean Cobb and kyphosis angles. The mean T1-T12 length increase was 26.2±7.1 (range, 16 to 40) mm, while the mean T1-S1 length increase was 43.3±15.0 (range, 24 to 70) mm. Complications developed in four (26.6%) of 15 patients. Definitive spinal fusion surgery was performed in seven patients. Total mean Cobb angle difference between the final follow-up and fusion surgery was 9.3° (p=0.016) and kyphosis angle difference was -2.1° (p=0.349). After fusion surgery, total lengthening in T1-T12 and T1-S1 distance was 10.5 mm (p=0.036) and 15.0 mm (p=0.022), respectively. A significant increase in all subdomain scores of the EOSQ-24 (p<0.05), except for financial impact, was recorded in all patients.

CONCLUSION

Dual MCGR technique is an effective, reliable, and robust treatment alternative for primary EOS. However, surgeons should be aware of the relatively high rate of complications. In addition, residual deformity can be corrected successfully with definitive surgery.

Fracture mechanisms in Ti and Co-Cr growing rods and impact on clinical practice

The widely used treatment of early onset scoliosis based on fusionless spinal instrumentation with growing rods suffers from severe complications due to premature rod failure. Only few studies have explored the fracture mechanisms in single rod constructs, while clinical practice urgently needs guidance. The objectives of this study are (i) to determine the failure mechanisms in Ti-6Al-4V alloy, Ti Cp 2 and Co-Cr alloy rods, and (ii) to propose strategies to reduce the risk of rod fracture. For this purpose, seven rods from three patients treated for early onset scoliosis were characterized by preoperative, pre-fracture X-rays and after-fracture X-rays. Fracture surface analysis, performed using scanning electron microscopy, revealed similar failure mechanisms for all rods, independent of composition and diameter. Fracture is caused by fatigue, associated to repeated bending action in the anteroposterior direction. Cracking initiates at multiple sites. Three-point bending fatigue tests on Ti-6Al-4V bent rods confirmed the fracture scenario. A beam bending model indicates that the failure process is controlled by the combination of cyclic vertical and horizontal forces with amplitudes from 200 N to 400 N and from 70 N to 150 N, respectively. Strategies to minimize fracture involve adaptations of material properties and rod geometry to scoliosis characteristics, including sagittal alignment, and spine behavior.

Early Complications in Vertical Expandable Prosthetic Titanium Rib and Magnetically Controlled Growing Rods to Manage Early Onset Scoliosis

OBJECTIVES

The aim of this study is to examine whether surgical treatment of early onset scoliosis (EOS) with magnetically controlled growing rods (MCGRs) or a vertical expandable prosthetic titanium rib (VEPTR) resulted in fewer short-term (24 months) complications and reoperations.

BACKGROUND

EOS is a challenging problem for spine surgeons that has been managed with different growth-friendly instrumentation systems. Although rib-based devices encourage spinal growth via regular lengthening, the high rate of complications and reoperations leads us to use spine-based devices such as MCGRs to mitigate this concern.

METHODS

A total of 35 EOS patients were included in the study. Twenty patients were included in the VEPTR group, and 15 patients were included in the MCGR group. Demographic data and 2 years of postoperative complications and reoperations were reviewed retrospectively. As secondary outcomes, radiographic outcomes were reported preoperatively and 1 year after surgery. Indications for this technique and complications were collected from the charts.

RESULTS

Demographic data showed no significant differences between the 2 groups. Significant differences were found in the complications rate at 2 years, with 65% complications in the VEPTR group and 13.3% complications in the MCGR group (P < .001). The reoperation rate at 2 years was also significantly higher in the VEPTR group, with 50% versus 13.3% in the MCGR group (P = .0009). As secondary outcomes, radiological parameters such as main curve Cobb angle correction (P = .001) and apical vertebral translation (P = .002) were significantly higher in the MCGR group. Significant differences were also found in sagittal profile parameters; T1-T12 and T1-S1 were significantly higher in the MCGR group (P < .001).

CONCLUSIONS

According to our results, VEPTR has significantly higher complication and reoperation rates at 2 years postsurgery compared with MCGR.

LEVEL OF EVIDENCE

4.

Minimum 5-Year Follow-up on Graduates of Growing Spine Surgery for Early Onset Scoliosis

INTRODUCTION

After discontinuation of growth friendly (GF) surgery for early onset scoliosis, patients undergo spinal fusion or continued observation. This last planned treatment is colloquially called "definitive" treatment, conferring these patients as "graduates" of a growing program. The 5-year radiographic and clinical outcomes of this cohort are unknown.

METHODS

An international pediatric spine database was queried for patients from a GF program (spine or rib-based) with minimum 5-year follow-up from last planned surgery (GF or spinal fusion). Radiographs and charts were reviewed for main coronal curve angle and maximum kyphosis as well as occurrence of secondary surgery.

RESULTS

Of 580 graduates, 170 (29%) had minimum 5-year follow-up (37% male). Scoliosis etiology was congenital in 41 (24%), idiopathic 36 (21%), neuromuscular 51 (30%), and syndromic 42 (25%). Index surgery consisted of spine-based growing rods in 122 (71%) and rib-based distraction in 48 (29%). Mean age at index surgery was 6.8 years, and patients underwent an average of 5.4 lengthenings over an average of 4.9 years (range, 6 mo to 11 y). Last planned treatment was at an average age of 11.8 years (range, 7 to 17 years). Last planned treatment consisted of spinal fusion in 114 patients, 47 had growing implants maintained, 9 had implants removed. Average follow-up was 7.3 years (range, 5 to 13 y).When compared from postdefinitive treatment to 2-year follow-up, there was noted progression of the coronal curve angle (46±19 to 51±21 degrees, P=0.046) and kyphosis (48±20 to 57±25 degrees, P=0.03). However, between 2 and 5 years, no further progression occurred in the coronal (51±21 to 53±21 degrees, P=0.26) or sagittal (57±25 to 54±28 degrees, P=0.93) planes. When stratified based on etiology, there was no significant coronal curve progression between 2- and 5-year follow-up. When comparing spinal fusion patients to those who had maintenance of their growing construct, there was also no significant curve progression.Thirty-seven (21%) underwent at least 1 (average, 1.7; range, 1 to 7) revision surgery following graduation, and 15 of 37 (41%) underwent 2 or more revision surgeries. Reason for revision was implant revision (either GF or spinal fusion) in 34 patients, and implant removal in 3. On an average, the first revision was 2.5 years after the definitive treatment plan (range, 0.02 to 7.4 y). In total, 15 of 37 (41%) revisions occurred over 2 years following the final decision for treatment plan, and 7 of 37 (19%) occurred 5 or more years after the definitive treatment.Patients who underwent spinal fusion as a definitive treatment strategy were more likely to undergo revision surgery (27%) than patients who had their GF implants maintained (11%) (P=0.04).

CONCLUSIONS

Five years following "graduation" from growing surgery for early onset scoliosis, there is progression of curve magnitude in both the coronal and sagittal planes up to 2 years, with no further progression at 5 years. A total of 21% of patients undergo at least 1 revision surgery, and average time to revision surgery is over 2 years from last planned surgery. Risk of revision surgery was higher in patients who underwent a spinal fusion as their definitive treatment strategy.

LEVEL EVIDENCE

Level III-retrospective comparative.

TYPE OF EVIDENCE

Therapeutic.

How frequent should the radiographic examination be to monitor magnetically controlled growing rods? A retrospective look two to seven years postoperatively

PURPOSE

Magnetically controlled growing rods (MCGR) allow more frequent outpatient lengthenings to better mimic the physiological growth. The assessment of distractions with radiographs raised concerns regarding ionizing radiation exposure in growing children. The aim was to assess the necessity of radiographs after every lengthening of MCGR.

METHODS

A retrospective analysis of 30 consecutive patients (19F, 11 M) treated in a single institution between 2011 and 2017. Planned radiographs were taken based on a protocol, updated over the years to involve less frequent acquisitions. Unplanned radiographs were obtained after a patient complaint or a significant clinical examination finding. Outcome measures were preoperative and postoperative radiographic measurements, and complications such as proximal and distal junctional kyphosis and failure, rod or actuator breakage, collapse of previously achieved height or failure to lengthen and worsening of deformity.

RESULTS

Mean age at surgery was 7.5 (4-11) years. Mean follow-up was 45 (24-84) months. Mean number of lengthenings and radiographs per patient were 14.4 (8-23), and 13.2 (5-46), respectively. Nine patients (30%) experienced a total of 13 mechanical complications. Almost all complications were detected in unplanned radiographs. The probability of detecting a mechanical complication was significantly lower (p < 0.00001) in planned radiographs.

CONCLUSIONS

Radiographs taken after routine lengthenings of MCGR are not likely to reveal any significant finding, since only 0.9% of planned radiographs displayed a mechanical complication. Exposing growing children to radiation with an intention of checking the MCGR device after every lengthening could not be justified. Obtaining post-lengthening radiographs with a decreased frequency and after a significant complaint or clinical finding may be considered.

Complications of dual growing rod with all-pedicle screw instrumentation in the treatment of early-onset scoliosis

BACKGROUND

Treatment of early-onset scoliosis (EOS) is still a challenge to patients, families, and surgeons. Previous studies have indicated that EOS patients are at high risk for complications following growth-friendly surgery. This study was performed to evaluate the results and complications of all-pedicle screw dual growing rod instrumentation in the treatment of EOS.

METHODS

In an IRB-approved retrospective study, we searched the electronic medical records of our institution for all patients who underwent posterior spinal instrumentation for scoliosis between March 2014 and March 2017. Patients under the age of 10 at the time of surgery who were treated with a growth-friendly technique were then selected. Patients with incomplete records and less than 2 years of follow-up were excluded. Charts, operative notes, clinic visits, and radiographs were extracted. Radiographs were reviewed, and the main curve Cobb angle, thoracic kyphosis, pelvic tilt, pelvic incidence, sacral slope, and proximal junctional angles were measured. We specifically looked for any intra-operative or post-operative complications. Statistical analysis was performed to determine the risk factors of complications.

RESULTS

A total of 42 patients with a mean age of 4.8 ± 2.1 years (range, 1.5-8 years) were included in the final analysis. Patients were followed for a median of 34 months (range, 24-55). The major curve was corrected from a mean of 42.9° ± 10.7° to 28.8° ± 9.6° at the latest follow-up. Proximal junctional angles and thoracic kyphosis increased significantly during the follow-up period (both P values < 0.001). A total of 7 complications (17%) were observed. Four patients (10%) developed superficial surgical site infections, all of which resolved with antibiotics and one round of surgical debridement. Three cases (7%) of proximal junctional kyphosis (PJK) were encountered during the study period, none of which required revision surgery. Pre-operative thoracic kyphosis was the only significant risk factor for the development of PJK.

CONCLUSIONS

Our findings suggest that in settings without access to magnetically controlled growing rods, dual growing rods with all-pedicle screw instrumentation is still a viable treatment strategy with comparable results and complications. The most common complications are infection and PJK, with the latter being associated with a larger pre-operative thoracic kyphosis.

Correction of the spine with magnetically controlled growing rods in early onset scoliosis : A pre-to-post analysis of 21 patients with 1‑year follow-up

BACKGROUND

Several studies have emphasized that the magnetically controlled growing rod (MCGR) technique decreases complications and costs and could be considered a safe procedure for treating patients with early onset scoliosis (EOS). To the best of our knowledge, the sagittal profile of patients with an implanted MCGR has not been sufficiently studied before.

OBJECTIVE

The objectives of this study were twofold: firstly, to evaluate the influence of MCGR on the coronal, sagittal and axial planes. Secondly, to analyze changes of cervical alignment post-MCGR implantation.

MATERIAL AND METHODS

This was a retrospective study of patients with EOS who underwent MCGR from 2012 to 2018. Patients were included if they presented with a thoracic or lumbar curvature greater than 40° (Cobb angle) and Risser's sign 0. Global analysis of all patients was reported. Patients were stratified preoperatively by thoracic alignment into a hypokyphotic or kyphotic group. Furthermore, the study population was divided into an anteriorly aligned group and a posteriorly aligned group. Sagittal alignment parameters and parameters of coronal and axial plane were measured and the preoperative to postoperative change was compared then analyzed 1 year after surgery. No external funding was procured for this research and the authors' conflicts of interest are not pertinent to the present work.

RESULTS

A total of 21 patients were included in the study. There was a significant coronal correction of the structural and compensatory curves (p < 0.01). Before and after surgery, the coronal C7 plumbline was unchanged and remained within the normal range. Postoperatively, a significant derotation of the apical vertebra in thoracic and lumbar curves was observed (p < 0.05). Global analysis of the sagittal profile revealed a significant decrease of TK (p < 0.001) and T9SPi (p = 0.002) with a simultaneous significant increase of T1T3 angle (p = 0.015) and T1T4 angle (p = 0.015). No significant changes of the sagittal parameters of cervical, lumbar and spinopelvic parameters were noted. Among all groups, cervical parameters did not reveal any statistically significant changes. At 1‑year follow up the T1T3 angle (p = 0.01) and T1T4 angle (p = 0.03) were significantly increased. All other measured parameters of sagittal, coronal and axial profile were unchanged.

CONCLUSION

The implantation of MCGR had a significant impact on the sagittal profile. Notwithstanding, no further compensatory mechanisms of the cervical spine and pelvis had to be recruited to safeguard sagittal alignment.

Continuous lengthening potential after four years of magnetically controlled spinal deformity correction in children with spinal muscular atrophy

Magnetically controlled growing rods (MCGR) are commonly implanted for the treatment of early-onset scoliosis. While most authors report favorable short-term results, little is known about long-term deformity correction. This prospective cohort study assesses spinal deformity control in a homogeneous spinal muscular atrophy (SMA) patient group treated with MCGR implants, a standardized lengthening protocol and a minimum follow-up of four years. 17 SMA patients with progressive scoliosis were treated with MCGR implanted parallel to the spine with rib-to-pelvis fixation. Radiologic measurements were performed before and after MCGR implantation and during external lengthening procedures. These included measurements of the scoliotic curve, kyphosis, lordosis, pelvic obliquity and the spinal length. Additional clinical data of the complications were also analyzed. 17 children (mean age 7.4 years) were surgically treated and underwent a total of 376 lengthenings. Complication rates were 3.5% in respect to all interventions or 41% of the patients had complications during 3.5% of the lengthening sessions. The initial implantation significantly reduced the main scoliotic curve by 59%, with the correction remaining constant throughout the follow-up. Pelvic obliquity was also significantly and permanently corrected by 72%, whereas kyphosis and lordosis were not influenced. The spinal length could be significantly increased mostly during the first year of treatment. Bilateral implantation of MCGRs for correction of spinal deformity in children with SMA showed no decrease of the lengthening potential during a four-year follow-up. Therefore, the previously described ‘law of diminishing returns’ could not be applied to this patient population.

Level of Evidence/Clinical relevance: Therapeutic Level IV.

Early-Onset Scoliosis Treated With Magnetically Controlled Growing Rods

The recently developed magnetically controlled growing rod (MCGR) system has gained popularity because it limits additional surgical lengthening procedures and promises reduction of the complication rate previously reported for the traditional growing rods. A retrospective single-center study was performed. Demographic and complications data were recorded. A statistical analysis was conducted to quantify the effect of MCGR placement and of subsequent lengthening on the Cobb angle, T1-T12 kyphosis, and the distances from T1-T12 and T1-S1. Twenty-four patients met the inclusion criteria. Six had idiopathic scoliosis and 18 patients had nonidiopathic scoliosis (neuromuscular and syndromic scoliosis). Nine patients underwent primary MCGR placement, and 15 had the traditional growing rods removed and replaced with MCGRs. The mean age at surgery and at last follow-up was 6.3 years and 8.8 years, respectively. The mean follow-up was 29.2 months. The MCGR placement significantly reduced the Cobb angle and kyphosis by an average of 21.33° and 10.79°, respectively. The T1-T12 and the T1-S1 distances increased an average of 1.19 and 1.89 cm/year, respectively, during the follow-up period. The average percentage of achieved-to-intended distraction was 65% on the concave side and 68% on the convex side at last follow-up. There were 9 postoperative complications in 8 (33%) patients, 6 of whom had nonidiopathic scoliosis. The MCGR system is reliable and effective in the treatment of patients affected by early-onset scoliosis. [Orthopedics. 2020;43(6):e601-e608.].

The potential of spring distraction to dynamically correct complex spinal deformities in the growing child

Purpose

Current treatment of progressive early onset scoliosis involves growth-friendly instrumentation if conservative treatment fails. These implants guide growth by passive sliding or repeated lengthenings. None of these techniques provide dynamic correction after implantation. We developed the spring distraction system (SDS), by using one or multiple compressed springs positioned around a standard sliding rod, to provide active continuous distraction of the spine to stimulate growth and further correction. The purpose of this study was to determine feasibility and proof of concept of the SDS.

Methods

We developed a versatile, dynamic spring distraction system for patients who would benefit from active continuous distraction. This prospective case series evaluates four patients with exceptional and progressive congenital spine deformities.

Results

Four patients had a mean age of 6.8 years at surgery with a mean follow-up of 36 months (range 25–45). The mean progressive thoracic lordosis, which was the reason for initiating surgical treatment in two patients, changed from 32° lordosis preoperatively to 1° kyphosis post-operatively. During follow-up, this further improved to 32° thoracic kyphosis. In the two other patients, with cervicothorcacic scoliosis, the main coronal curve improved from 79° pre-operatively to 56° post-operatively and further improved to 42°. The mean T1-S1 spine growth during follow-up for all patients was 1.3 cm/year. There was one reoperation because of skin problems and no device-failures.

Conclusion

These early results show the feasibility and the proof of concept of spring-based distraction as a dynamic growth-enhancing system with the potential of further correction of the deformity after implantation.

Lengthening of magnetically controlled growing rods caused minimal pain in 25 children: pain assessment with FPS-R, NRS, and r-FLACC

STUDY DESIGN

Descriptive case series.

OBJECTIVE

The aim of the study is to investigate the pain associated with magnetically controlled growing rod (MCGR) lengthening procedures. MCGRs have gained popularity because they offer non-surgical lengthening procedures in early-onset scoliosis (EOS) instead of semi-annual open surgery elongations with traditional growing rods. Many aspects of MCGR treatment have been investigated, but pain in conjunction with distraction is only sparsely described in the literature.

METHODS

Pain intensity was assessed in 25 EOS patients before, during and after MCGR lengthening procedures in an outpatient setup. They underwent at least two (range 2-16) lengthening procedures prior to this study. The pain intensity was estimated using patient-reported Faces Pain Scale (FPS-R), caregiver-reported pain numeric rating scale (NRS), and NRS and revised Face, Legs, Activity, Cry, Consolability scale (r-FLACC) by two medically trained observers. The inter-rater reliability and correlation between instruments were analyzed.

RESULTS

23 of 25 EOS patients (8- to 16-year old) with mixed etiology were able to self-report pain. The average pain intensity was mild: median 1 (range 0-6) on all four instruments on a 0-to-10 scale. Afterward, 22/25 patients (88%) were completely pain free and the remaining 3 patients had a pain score of 1. MCGR stalling (i.e. clunking) was encountered in 14/25 (56%) of the patients without impact on the pain intensity.

CONCLUSIONS

The average maximum pain intensities during the lengthening procedures were mild and pain ceased within few minutes. The inter-rater reliability was good to excellent for NRS and r-FLACC, and there were high correlations between all the four pain instruments, indicating high criterion validity.

LEVEL OF EVIDENCE

Level IV, case series.

VEPTR Treatment of Early Onset Scoliosis in Children Without Rib Abnormalities: Long-term Results of a Prospective, Multicenter Study

BACKGROUND

In 2007, this prospective study on vertical expandable prosthetic titanium rib (VEPTR) treatment of early onset scoliosis in children without rib abnormalities was initiated. Two-year follow-up results have previously been reported. This study examines whether, at 5-year follow-up, VEPTR continues to control scoliosis and allow spinal growth.

METHODS

A prospective, multicenter, observational cohort design was used. Patients underwent traditional VEPTR implantation ≥5 years before analysis. Preimplantation and last available images were compared, regardless of whether VEPTR remained in vivo. Additional analysis was performed if VEPTR was in vivo ≥5 years.

RESULTS

This study included 59 patients (mean age at VEPTR implantation, 6.1±2.4 y; mean follow-up, 6.9±1.4 y). Currently, 24 patients still have VEPTR, whereas 24 have converted (13 fusions, 6 MCGR, 3 growing rods, 1 hybrid, and 1 Shilla). Three have had VEPTR explanted, 6 are unknown, and 2 have deceased. On last available imaging (n=59; mean follow-up, 4.8±1.9 y), scoliosis improved from 71.8±18.0 degrees preoperatively to 60.9±20.3 degrees (P<0.001) and T1- T12 height increased (15.8±3.2 to 19.3±3.8 cm, P<0.001). T1-S1 height also increased (24.8±4.4 to 31.2±5.3 cm, P<0.001), representing 119% age-matched growth. Composite improvement of scoliosis, T1-T12, and T1-S1 height was achieved in 79% of patients. A subset of 29 patients with VEPTR was analyzed at most recent follow-up ≥5 years while VEPTR remained in vivo (24 patients with VEPTR above, and 5 who later converted to other devices). Mean age at implantation was 5.0±2.2 years, with a mean VEPTR treatment duration of 6.2±1.1 years. Scoliosis improved from preoperatively (69.3±14.5 to 61.6±16.1 degrees, P=0.006), with mild recurrence from postoperative to 5 years. T1-T12 height increased (15.0±3.3 to 18.7±3.3 cm, P<0.001) and T1-S1 height increased (23.7±4.5 to 30.1±4.6 cm, P<0.001), representing 83% age-matched growth. Composite improvement was achieved in 83% of patients. Instrumented sagittal length also increased during this period (21.8±4.2 to 30.3±5.1 cm, P<0.001).

CONCLUSION

At a 5-year follow-up, VEPTR continues to control scoliosis and allow spinal growth.

LEVEL OF EVIDENCE

Level II-prospective cohort, therapeutic study.

Clinical Outcome of Magnetically Controlled Growing Rod in Early-onset Scoliosis: A Systematic Review

STUDY DESIGN

This was a systematic literature review.

OBJECTIVE

To evaluate the efficacy and safety of magnetically controlled growing rod (MCGR) in treating early-onset scoliosis.

SUMMARY OF BACKGROUND DATA

Preliminary studies reported the promising potential of MCGR in deformity correction and spine growth preservation with noninvasive distraction. This study was conducted on the basis of data from published literatures.

MATERIALS AND METHODS

A systematic search from multimedical database was conducted for studies of MCGR. Involved studies should provide at least one of the followings: deformity correction, spine growth, and complication. During treatment period, improvement or progression of scoliosis/kyphosis, annual T1-S1/T1-T12 extension, incidence of complication, and unplanned surgery were summarized and the correlations with term of follow-up were investigated.

RESULTS

In total, 13 studies (n=249) were involved, with an average of 22.2-month follow-up. Scoliosis correction was well maintained, improving from 36.4 degrees at postinitial to 37.1 degrees at last follow-up (P=0.794). Kyphosis progressed from 28.8 degrees at postinitial to 34.4 degrees at last follow-up (P=0.024). Annual T1-S1 and T1-T12 longitudinal extensions were 8.7 and 4.7 mm/year, respectively. As follow-up went on, no significant decline was observed in annual extension of T1-S1 (P=0.4680) or T1-T12 (P=0.8053). The incidences of alignment-related, implant-related, and wound-related complication were 3.5%, 30.1%, and 6.9%, respectively. No significant correlation was observed between occurrence of complication and term of follow-up. The rate of receiving unplanned surgery was 24.3%.

CONCLUSIONS

MCGR is efficient in the maintenance of coronal correction and preservation of spine growth, with loss of sagittal correction and a 24.3% unplanned revision rate.

Staged instrumentation with magnetically controlled growing rods in early-onset scoliosis: indications and preliminary outcomes

BACKGROUND

Severe scoliosis, kyphosis, stiffer curves, short trunk height, and poor bone density are known risk factors for instrumentation failure with traditional growing rods or magnetically controlled growing rods (MCGR). To minimize the risk of instrumentation failure in managing complex early-onset scoliosis (EOS) with MCGR, we propose a strategy for staged MCGR insertion.

METHODS

We performed a single-center retrospective review of all consecutive MCGR cases with 24 months' minimum follow-up. Inclusion criteria included diagnosis of EOS of any etiology with severe and stiff curves in the coronal or sagittal planes, poor bone density, short trunk height (T1-T12 smaller than 150 mm) or previous instrumentation failure managed with staged MCGR. During the first stage, anchor points and halo-gravity were applied, followed by halo-gravity traction. At a second stage, halo-gravity was removed and MCGR were inserted. Outcome measures included pre- and postoperative radiographic measurements and complications.

RESULTS

Seventeen patients with a median age of 7 (range 6-9) years were managed in two stages. Indications for two-stage surgery were short trunk height (T1-T12 height less than 150 mm) in six patients, five poor bone quality, three dislodgement of proximal anchor points in previous instrumentation, and three rigid curves. The rate of unplanned revision surgeries was 11.8%. No infections or traction-related complications were found.

CONCLUSIONS

According to our results, the staged MCGR insertion strategy combined with halo-gravity traction to manage complex EOS yielded a relatively low instrumentation failure rate as compared with the rates previously reported in the current literature. To our knowledge, this is the first study reporting the staged strategy for instrumentation with MCGR.

LEVEL OF EVIDENCE

IV.

A high degree of variability exists in how "safety and efficacy" is defined and reported in growing rod surgery for early onset scoliosis: a systematic review

Established criteria for reporting safety and efficacy have not yet been defined in growing rod surgery for early onset scoliosis. A systematic literature review revealed a high degree of variability in how authors stratified complications and patient outcomes as a means to define safety and efficacy for this challenging patient population.

INTRODUCTION

Several publications have reported the safety and efficacy of traditional growing rods (TGR) and magnetically controlled growing rods (MCGR) using various parameters. Radiographic parameters are most commonly used to measure efficacy, while incidence and type of complications are used to assess safety. A systematic review of peer-reviewed articles was performed to identify whether a consensus exists in how safety and efficacy parameters are reported in EOS patients treated with TGR and MCGR.

HYPOTHESIS

There is no consensus on the parameters used for reporting safety and efficacy in growing rod treatment for early onset scoliosis.

STUDY DESIGN

Systematic literature review.

METHODS

Four databases were searched on November 10, 2016 to identify all qualified peer-reviewed articles using specific keyword searches. All peer-reviewed articles published in English language reporting any data related to safety and efficacy of the TGR and/or MCGR surgical technique were included. Articles that met the inclusion criteria were scored by modified Downs and Black scoring system (J Epidemiol Community Health 52(6):377-384, 1998) for non-randomized studies. All reported safety and efficacy data were extracted and analyzed.

RESULTS

Search of the databases resulted in 111 unique citations including: PubMed (50), Embase (68 with 21 duplicates), Web of Science (29 with 15 duplicates), and CINAHL (15; all duplicates). Fifty-six of 111 citations were excluded during the review of the titles and abstracts. In addition, 16 citations were excluded at the time of full manuscript review. The remaining 39 articles included 23 TGR (2007-2016) and 16 MCGR papers (2012-2016). The overall Downs and Black score was 63.9 for TGR papers vs. 64.0 for MCGR papers (p = 0.97). Efficacy measures were not consistently reported among the publications. The only consistently reported efficacy parameter in majority (> 90%) of papers was curve size. Complication reporting was highly variable.

CONCLUSION

Major curve size was the only consistent parameter to report efficacy in peer-reviewed TGR and MCGR publications. Since complications were not consistently reported, assessing safety of either treatment was infeasible. Establishing standardized safety and efficacy parameters in growing rod surgery for EOS would improve the quality of future studies and makes comparison of different treatment modalities possible. Indeed, other clinically relevant parameters such as health-related quality of life, pulmonary function, nutritional status, and psychiatric and developmental health should also be considered to improve the future safety and efficacy reporting.

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.

Prospectively collected surgeon indications for discontinuation of a lengthening program for early-onset scoliosis

INTRODUCTION

At some point after children with early-onset scoliosis (EOS) undergo implantation of a distraction construct to control deformity and promote growth, a decision is made to discontinue lengthening. The purpose of this study was to evaluate surgeon indications for discontinuation of a lengthening program and to evaluate patient outcomes.

METHODS

As a part of a multicenter database, surgeons prospectively completed a questionnaire at the completion of growth-friendly treatment. Surgeon indications for discontinuation included patient age, pain/functional status, implant status, and spinal deformity parameters. Patient demographics, scoliosis type, deformity parameters, and length of time in a growing program were queried. Patients were treated with a final fusion or observation, and rate of secondary surgeries was analyzed.

RESULTS

Questionnaires were completed on 121 patients (61% female). EOS etiology was 31% neuromuscular, 43% congenital, 16% idiopathic, and 10% syndromic. Average age at initiation of growing program was 6.8 ± 3.1 years, and average age at discontinuation was 12.7 ± 2.5 years. The most commonly cited indications for discontinuation of a lengthening program included bone age/skeletal maturity (n = 46), patient age (n = 33), and diminishing returns with expansions (n = 33). A larger coronal Cobb angle was found in patients who underwent definitive fusion (65°) when compared with continued observation (55°, p = 0.001). Twenty-nine (24%) patients were initially treated with observation after completion of a growing construct. In this subgroup, at a minimum of 2 years' (average 3.8 years') follow-up, 26/29 (90%) patients remained stable with observation alone; whereas, three (10%) underwent delayed final fusion surgery.

CONCLUSIONS

The most common surgeon-cited indications for discontinuation of a lengthening program in EOS patients are skeletal maturity and patient age. The majority of patients (76%) underwent definitive spinal fusion after discontinuation of a lengthening program; whereas, those treated with observation alone had a survivorship of 90% at a minimum follow-up of two years.

In Vitro Biomechanical Validation of a Self-Adaptive Ratchet Growing Rod Construct for Fusionless Scoliosis Correction

STUDY DESIGN

In vitro biomechanical evaluation of a novel self-adaptive unidirectional ratchet growing rod (RGR) system.

OBJECTIVE

The aim of this study was to propose and biomechanically validate a novel RGR construct in vitro using porcine thoracic spines and calculate the tensile force required to elongate the RGR with springs, without springs, and with soft tissue encapsulation (induced in vivo in rabbits).

SUMMARY OF BACKGROUND DATA

Literature lacks clear consensus regarding the implant of choice for early-onset scoliosis. Multiple systems are currently available, and each has its own advantages and disadvantages. Therefore, studying novel designs that can credibly accommodate growth and curb deformity progression is of principle importance.

METHODS

In vitro biomechanical motion tests were done using six porcine thoracic spines with pedicle screws at T3 and T8. A pure moment of ±5 Nm was loaded in lateral bending (LB) and flexion-extension. Range of motion (ROM) and neutral zone (NZ) of each specimen was determined after connecting the free movable growing rods (FGRs), RGRs, and standard rods (SRs). Tensile tests were done to measure the force required to elongate the RGR with springs, without springs, and with soft tissue encapsulation (induced in vivo in rabbits).

RESULTS

Global ROM, implanted T3-T8 ROM, and the NZ of specimens with FGRs and RGRs were significantly higher than that with SRs. The RGRs favored unidirectional elongation in both LB and flexion. The tensile forces required for elongating the RGR without springs, with springs, and with soft tissue capsulation (by a scaled unit of 3 mm) were 3 ± 1.3 N, 10.5 ± 0.4 N, and 48.4 ± 14.4 N, respectively.

CONCLUSION

The RGR could stabilize and favor unidirectional elongation of the implanted spinal column when appropriate forces were present. There was no device failure as far as we have studied and it is anticipated that, with further safety and feasibility assessment, RGRs could be adapted for clinical use.

LEVEL OF EVIDENCE

N/A.

Magnetically controlled growing instrumentation for early onset scoliosis: Caution needed when interpreting the literature

BACKGROUND

Magnetically controlled growing rods (MCGR) are a novel treatment option for early onset scoliosis (EOS). Although the complication profile with MCGR use has been reviewed, these reviews do not take into account important implants modifications, termed iterations, that were made due to early on postoperative complications is not well reported or understood.

AIM

To assess the effect of MCGR implant iterations on post-operative complications in EOS.

METHODS

A systematic review was performed to identify studies investigating MCGR specifically for the treatment of EOS, refined to those reporting the implant iteration, specifically the incorporation of the keeper plate to the implant design. Articles with mixed implant iteration usage were excluded. Complications following surgery were recorded as well as potential risk factors and compared between implant cohorts.

RESULTS

Although 20 articles were identified for inclusion, 5 included mixed implant iteration leaving a total of 271 patients identified through 15 clinical studies that met inclusion criteria. The average follow-up was 25.4-mo. Pre-keeper plate implants were utilized in 3 studies with a total of 49 patients. Overall, 115 (42.4%) post-operative complications were identified, with 87% defined as major. The addition of the keeper plate significantly decreased the rate of post-operative complications per study (35.7% vs 80.6%, P = 0.036), and the rate of distraction failure (8.1% vs 40.8%, P = 0.02). Unplanned reoperation occurred in 69 (26.7%) patients but was not different between implant iteration cohorts (25.5% without keeper plate vs 27.1% with keeper plate, P = 0.92).

CONCLUSION

MCGR for EOS has a cumulative complication rate of 42.4% but this is significantly reduced to 35.7% when reviewing only keeper-plate enabled implants. However, 25% of published articles included mixed implant iterations. Future studies should discern between implants iterations when reporting on the usage of MCGR for EOS.

Use of a distraction-to-stall lengthening procedure in magnetically controlled growing rods: A single-center cohort study

PURPOSE

The objective of this study was to assess the outcome of patients treated with magnetically controlled growing rods (MCGRs) using a standardized distraction procedure with intended distraction-to-stall and to compare the outcomes between idiopathic and nonidiopathic patients.

METHODS

This was a retrospective single-center cohort study. Conversion cases were excluded. Distractions were performed with 2- to 3-month intervals with the intention of distraction-to-stall on both rods. Distraction length was measured on X-rays every 6 months. Spinal height was assessed using T1-T12 and T1-S1 annual increase.

RESULTS

19 patients (eight idiopathic and 11 nonidiopathic) were included. Mean age at surgery was 9.7 ± 1.9 years, and median follow-up was 1.9 years (interquartile range (IQR): 1.3-2.2). Major curve improved from median 76° (IQR: 64-83) preoperatively to 42° (IQR: 32-51) postoperatively ( p < 0.001) corresponding to a curve correction of 43% (IQR: 33-51). Correction was maintained at 1- and 2-year follow-up. Median annual T1-T12 and T1-S1 height increase were 10 mm (IQR: 6-16) and 11 mm (IQR: 7-33), respectively. A total of 159 distraction procedures were performed; 83.5% of these were distracted-to-stall, and 16.5% were stopped due to discomfort. Median rod distraction per procedure was 2.0 mm (IQR: 1.6-2.7) for the concave side and 1.7 mm (IQR: 1.4-2.5) for the convex side. Five patients had implant-related complications. Patients with nonidiopathic etiology were significantly younger and had lower flexibility compared with idiopathic patients ( p ≤ 0.040). However, we found no statistically significant difference in curve correction, spinal height increase, distraction length, or complications between the two groups ( p ≥ 0.109).

CONCLUSION

MCGR effectively corrected the deformity and increased spinal height using a distraction procedure with intended distraction-to-stall. Five of 19 patients had implant-related complications, and we found no difference in the outcomes between idiopathic and nonidiopathic patients.

Outcomes of Primary and Conversion Magnetically Controlled Growth Rods Are Different at Two-Year Follow-up: Results of North American Release

STUDY DESIGN

Multicenter retrospective review.

OBJECTIVES

To compare the radiographic outcomes and complication rates in patients with primary and conversion magnetically controlled growing rod (MCGR) implants at one and two years after surgery.

SUMMARY OF BACKGROUND DATA

Many initial early-onset scoliosis (MCGR) implantations in the United States were conversions from other types of growth-friendly systems, and the outcome similarities and differences between primary and conversion MCGR implantation procedures are still relatively unknown.

METHODS

Multicenter retrospective review of EOS patients from two multicenter EOS registries identified consecutive EOS patients treated from 2014 to 2017 with a minimum of one-year follow-up. In addition, a subset of these patients who had two-year follow-up were further analyzed.

RESULTS

In total, 383 MCGR patients were identified, of which 272 (71%) were primary (P) and 111 (29%) were conversion (C). Group P patients had significantly greater coronal curves at the time of MCGR implantation and greater initial coronal correction. There was no statistically significant difference in Cobb correction at one year or between follow-up at one and two years. The preimplantation thoracic spine height was identical in both groups, with statistically greater improvement at initial implantation in P than in C patients. Significantly greater height gains were seen in P than in C patients in the one-year follow-up cohort. There was a higher rate of complications in the C group than in the P group; however, the difference was not statistically significant. Overall, most complications were implant-related. No loss of curve correction occurred in either group.

CONCLUSIONS

Patients with primary MCGR insertion can be expected to have greater radiographic correction and spine length gain than those with conversion from growth-friendly instrumentation to MCGR, most likely because of increased spine stiffness in conversion patients. The rate of complications, primarily implant-related, remains higher in conversion than in primary insertion patients.

LEVEL OF EVIDENCE

Level III.

Magnetically Controlled Growing Rods in Treatment of Early-Onset Scoliosis: A Single Center Study With a Minimum of 2-Year-Follow up and Preliminary Results After Converting Surgery

STUDY DESIGN

Case series.

OBJECTIVE

To evaluate complications and radiographic parameters after magnetically controlled growing rod (MCGR) index surgery (IS), during lengthening and following converting surgery (CS) with a minimum of 2-year follow up (FU).

SUMMARY OF BACKGROUND DATA

MCGR are maintaining skeletal growth in treatment of early onset scoliosis (EOS). There is no data regarding correction potential after CS available.

METHODS

Twenty-four cases were included. Two patients with rib and pelvic hook fixation instead of pedicle screws and three patients with previous spinal surgery were excluded from radiographic analysis.

RESULTS

Twenty-one patients received grade 3 or 4 in Classification of Early-Onset-Scoliosis (C-EOS) for main curve severity. The kyphotic modifiers (-) were given to seven and (+) to seven patients. Mean age at IS was 10.5 ± 2.4 years with a mean FU time of 42.3 ± 11.3 months. Deformity correction was only achieved during IS (46%) and CS (36%). During MCGR treatment a 5° loss of correction seen, while 25 mm of T1-S1 length was gained during the lengthening period. An overall average lengthening of 1.6 mm per lengthening procedure was achieved. Possibility to gain length during distractions decreases over time. No major failure of the distraction mechanism was observed, only 16 lengthening procedures failed within a total of 264 lengthening procedures. A total of 19 revision surgeries in 10 patients were observed. Four patients received more than one revision surgery.

CONCLUSION

Applying MCGR results in a revision rate of 0.23 per patient and per one FU year, while making further lengthening procedures obsolete compared with conventional growing rod techniques. Correction of major curve is possible during IS und CS. The law of diminishing returns applies during the period of lengthening.

LEVEL OF EVIDENCE

4.

An Overview of the Current State of Pediatric Scoliosis Management

Historically pediatric scoliosis represents a condition deeply rooted within the origins of orthopedic surgery. Today only a few subspecialized surgeons treat pediatric scoliosis patients. In severe cases surgery can hold progression of and correct pathologic spinal curvature. The goal of this article is to provide an overview of the current state of pediatric scoliosis management. It aims to increase the attention of general physicians and orthopedic surgeons to a niched but rather frequently encountered pediatric pathology to facilitate early recognition and diagnosis. A thorough research of literature was conducted to summarize the different scoliosis types, their etiology and presentation. Classification, normal human growth phases and curve progression risk have been further elaborated. Finally, current treatment options with their benefits, shortcomings and complications were laid out and discussed. Among the etiological groups a focus was put on idiopathic scoliosis, in particular adolescent idiopathic scoliosis as the most frequently encountered subtype.

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

Magnetically controlled growing rods have been used to treat early-onset scoliosis for the last 9 years; however, few studies have been published, with only short-term follow-up. The aim of the present study is to systematically review the outcomes of magnetically controlled growing rods in the treatment of early-onset scoliosis with a minimum of 2-year follow-up. Studies were included if patients with early-onset scoliosis (scoliosis diagnosed before 10 years of age) underwent implantation of magnetically controlled growing rods with a minimum of 2-year follow-up. The literature review and data extraction followed the established preferred reporting items for systematic review and meta-analysis guidelines. Data of distraction frequency, number of distractions, distracted length, Cobb angle, kyphosis, T1-T12 length, and T1-S1 length preoperatively, postoperatively, and at final follow-up were collected. Data regarding complications and unplanned reoperations were also extracted. The mean values of these parameters were calculated, or pooled meta-analysis was performed if available. Ten articles were included in this systematic review, with a total of 116 patients and a follow-up period between 23 and 61 months. The mean preoperative Cobb angle and kyphosis angle were 60.1° and 38.0°, respectively, and improved to 35.4° and 26.1° postoperatively. At final follow-up, the Cobb and kyphosis angles were maintained at 36.9° and 36.0°, respectively. The average preoperative T1-T12 and T1-S1 lengths were 180.6 mm and 293.6 mm, respectively, and increased to 198.3 mm and 320.3 mm postoperatively. T1-T12 and T1-S1 lengths were 212.3 mm and 339.3 mm at final follow-up, respectively. The overall rate of patients with complications was 48% (95% confidence interval [CI], 0.38-0.58) and unplanned reoperation 44% (95% CI, 0.33-0.55) after sensitivity analysis. The current evidence from different countries with a minimum of a 2-year follow-up suggests that magnetically controlled growing rods are an effective technique to treat pediatric scoliosis and promote spine growth. However, nearly half of patients still developed complications or required unplanned reoperations.

[Surgical "no-touch" distraction technique to correct pediatric scoliosis]

OBJECTIVE

Reduction and retention of the scoliotic curve in children with progressive spinal deformities.

INDICATIONS

Progressive neuromyopathic scoliosis which cannot be controlled conservatively (especially by walking disability), and/or development of a thorax insufficiency syndrome (TIS).

CONTRAINDICATIONS

Insufficient soft tissue coverage; body weight < 11.4 kg; body mass index (BMI) > 25 or >50 kg; missing osseous anchoring structures (ribs); adult skeleton (usually age < 12 years at surgery); severe spasticity.

SURGICAL TECHNIQUE

Indirect correction and distraction of the spinal deformity by two extendable, paravertebral telescopic implants, anchored to the cranial ribs and the iliac crest; the spine is not compromised surgically.

POSTOPERATIVE MANAGEMENT

Early functional therapy, no brace; multiple surgical (VEPTR®-system) or externally (magnetically controlled rods) controlled extensions per year.

RESULTS

The surgical paravertebral "no-touch" technique for spine correction is particularly suitable for children with neuromyopathic scoliosis with a body weight > 11.4 kg. Our prospective group of children (n = 45), was treated with a combination of the classic vertical expandable prosthetic titanium rib (VEPTR®) anchored to the ribs and iliac crest combined with a magnetically controlled telescopic implant (MAGEC®). The primary correction of >50% was achieved, while progression was effectively prevented over years. In 495 outpatient lengthening procedures, the rate of implant-associated complications requiring surgery was 3.7%. Of the 45 children, 13 (29%) underwent surgical revision. With the proposed surgical "no-touch" technique for scoliosis correction of pediatric neuromyopathic deformities, an effective reduction of the scoliotic curve can be achieved and maintained. Advantages of the method are a partial retention of spinal flexibility and a reduction of spinal ossifications, which facilitates dorsal spondylodesis as the final treatment.

High Correlation Between Achieved and Expected Distraction Using Magnetically Controlled Growth Rods (MCGR) With Rib to Pelvis Fixation in Pediatric Spine Deformity

PURPOSE

Magnetically controlled implant systems have been established to treat severe progressive spinal deformity in children. The purpose of this study was to evaluate (1) the ratio between achieved and expected distraction length, (2) the complication rate and its risk factors as well as (3) the correlation of the distraction length and the length of the spine.

METHODS

A total of 40 patients with an average follow-up of 34 (14 to 57) months were prospectively included in the study. Children underwent lengthening procedures every three months. The ratio between the distraction lengths was determined by comparing the measured distraction length of the rod on radiographs with the distraction length displayed on the external remote controller for the magnetically controlled growing rod (MCGR). Age, weight, height, and complications were repeatedly recorded.

RESULTS

The analysis of 746 procedures showed the actual distraction to be 94.4% of the expected one. No difference between implants on the concave and convex spinal side was observed. The overall complication rate was 4.6% mainly because of failure of the implant or lack of implant extension, which was directly related to an increased BMI. There was also a strong correlation between achieved implant distraction length and gain in spinal length.

CONCLUSIONS

Our study demonstrates a high ratio (0.94) between achieved and expected distraction length of magnetically controlled spinal rods. The complication rate was low (4.6%) and correlated to a high BMI. The correlation between the achieved implant distraction length and spinal length indicates the efficiency of the MCGR therapy.

LEVEL OF EVIDENCE

Therapeutic Level IV.

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.

Early Onset Scoliosis: Is there an Improvement in Quality of Life With Conversion From Traditional Growing Rods to Magnetically Controlled Growing Rods?

BACKGROUND

Modern treatment of early onset scoliosis (EOS) includes implantation of traditional growing rods (TGR) or magnetically controlled growing rods (MCGR) for posterior-based distraction if nonoperative treatment plans failed. The recent MCGR innovation has largely been expected to improve patient and family burden by avoiding frequent return to the operating room. At least one study has shown no HRQoL difference between TGR and MCGR, but none have specifically investigated a cohort of conversion patients whose families have experienced both.

METHODS

An EOS database was queried for all patients treated with TGR, MCGR, and those converted from TGR to MCGR who had at least 1 pretreatment and 1 posttreatment HRQoL assessment (EOSQ-24). Data on demographics, diagnoses, and major curve size, as well as EOSQ-24 domain scores were studied.

RESULTS

There were 156 TGR, 114 MCGR, and 32 conversion patients, with an average of 2.0 years between first and final EOSQ-24 surveys. There was no significant difference in outcome in any EOSQ-24 domain between the converts and the other 2 treatment groups. There was a significant post-op improvement in MCGR versus TGR in transfers and energy level (P=0.01; P=0.01).

CONCLUSIONS

Although patient families and their surgeons may subjectively report improved HRQoL after conversion from TGR lengthenings to in-office MCGR lengthenings, these improvements were seen in transfer and fatigue domains, not burden or satisfaction. Although the EOSQ-24 is a well-validated EOS metric, it may not be sensitive enough to overcome the QoL floor-effect associated with the diagnosis itself, or perhaps the improvement in QoL must be assessed over a longer interval to assess meaningful change.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Use of Magnetic Spinal Growth Rods (MCGR) With and Without Preoperative Halo-gravity Traction (HGT) for the Treatment of Severe Early-onset Scoliosis (EOS)

BACKGROUND

Correction of severe scoliosis through distraction-based techniques poses a challenge. Magnetically controlled growing rod (MCGR) hardware complications are common with a 27.8% to 46.7% revision rate in under 2 years. Loss of correction and diminishing returns are the norm. Treatment of severe scoliosis with halo-gravity traction (HGT) before MCGR has not been previously reported. The purpose of this study was to assess initial correction, maintenance of correction, and complication rate in patients with severe scoliosis treated with and without HGT before MCGR.

METHODS

IRB-approved retrospective single site cohort study of a prospectively collected database. Forty-two patients underwent MCGR between 2014 and 2017 at a single site, 12 with prior growing constructs were excluded, 30 patients were included, 12 patients underwent preoperative HGT. Charts were reviewed for demographic, clinical, and radiographic information.

RESULTS

The HGT group had larger major curves averaging 90 (69 to 114) degrees versus 77 (56 to 113) degrees in the non-HGT group P=0.018. Percent correction on preoperative flexibility films were 17% versus 40% for those in the HGT versus non-HGT group, P=0.000. An additional 22% correction of the curve magnitude occurred between the flexibility and in-traction films representing 43% of the total correction achieved, P=0.000, was achieved. EBL, and postoperative major curve and major curve correction were not significant. Thirteen percent of patients experienced complications. Average follow-up was 712 versus 561 days in the HGT versus non-HGT groups.

CONCLUSIONS

Large, rigid curves can achieve equivalent correction to flexible curves with HGT. Forty-three percent of the total correction achieved occurred during traction. Thirty percent of the total correction occurred at implantation of the MCGR in the HGT group versus 28% in the non-HGT group. At most recent follow-up HGT patients had statistically maintained their major curve correction better than non-HGT patients.

LEVEL OF EVIDENCE

Level III-therapeutic study.

Is Magnetically Controlled Growing Rod the Game Changer in Early-onset Scoliosis? A Preliminary Report

BACKGROUND

Magnetically controlled growing rod (MCGR) concept was introduced with the premise of minimizing the repetitive lengthening surgeries, which is default in traditional growing rod (TGR) treatment for early-onset scoliosis (EOS). Despite good radiographic outcomes, previous studies did not compare identical patient groups in terms of etiology and deformity characteristics; therefore, a true comparison of the MCGR and TGR is essential. This study was designed to compare 2 techniques in terms of clinical, radiologic, and health-related quality of life (HRQoL) outcomes.

METHODS

Patients with long sweeping congenital curves who underwent convex growth arrest and concave distraction (with TGR or MCGR) were retrospectively reviewed. Instrumented all-posterior convex growth arrest and concave distraction with growing rod technique were performed. Demographic parameters, follow-up time, number of lengthening procedures, radiographic parameters, number of unplanned surgeries, and complications were recorded. The Early-Onset Scoliosis Questionnaire (EOSQ-24) was used to evaluate HRQoL outcomes.

RESULTS

A total of 20 patients were included (10 MCGR, 10 TGR). No significant differences were found with regard to average age, follow-up time, radiographic parameters, or complications. Overall surgery per patient including index surgery, and planned and unplanned procedures were significantly lower in the MCGR group (8.8 vs. 1.3) (P=0.01). No patient in either group had graduated from growing rod treatment. HRQoL analysis revealed no significant difference between the 2 groups in any specific domain or in the overall score of the EOSQ-24.

CONCLUSIONS

Although equally effective in controlling the deformity and superior in reducing the number of surgeries with comparable complication rates, MCGR does not offer any significant improvement in HRQoL outcomes or the overall complication rate. Despite the obvious advantages, according to this preliminary report, the current technology and technique of MCGR may not be sufficient to be the long-awaited "game changer" in the treatment of EOS.

Two-stage posterior spinal fusion for early-onset scoliosis: Two case reports

RATIONALE

Fusionless techniques for early-onset scoliosis (EOS) have evolved to allow near-normal growth while maintaining the correction achieved during the initial surgery. However, such procedures require repeated surgeries and have increased complication rates. We have developed a 2-stage fusion technique using pedicle screws for EOS to reduce patient burden and complication risk. This series describes the clinical and radiological features of 2 patients with EOS who received 2-stage posterior spinal fusion. This surgical method for EOS represents the first of its kind.

PATIENT CONCERNS

Case 1 was a 10-year-old girl who was diagnosed as having scoliosis with Prader Willi syndrome at the age of 2 years. Her preoperative major curve Cobb angle was 100 degrees at age 10 years. Case 2 was an 11-year-old boy who was found to have scoliosis with 22q11.2 deletion syndrome at the age of 4 years. His preoperative major curve Cobb angle was 77 degrees at age 11 years.

DIAGNOSIS

Whole-spine radiographs were performed to diagnose scoliosis.

INTERVENTIONS

Both patients received 2-stage posterior spinal fusion.

OUTCOMES

Postoperative Cobb angle of the major curve improved to 46 and 48 degrees, respectively. Thoracic height respectively improved from 160 and 148 mm before surgery to 206 and 211 mm at final follow-up. Surgical outcome as evaluated by Scoliosis Research Society-22 patient questionnaires revealed acceptable results without any severe complications.

LESSONS

Based on the present case report, 2-stage posterior spinal fusion for EOS achieves good radiological and clinical outcomes without severe complications.

A novel technique for the subfascial insertion of magnetically controlled growing rods - The Alder Hey technique

Purpose:

In this study, we would like to describe a novel technique for subfascial insertion of magnetically controlled growing rods using chest drain during surgery for early-onset scoliosis.

Materials and Methods:

Posterior approach, surgical dissection to the spine is performed exposing the relevant anatomy to allow placement of pedicle screws always in the distal construct and pedicle screws or hooks in the proximal construct. To allow easy passage of the Magnetic Expansion Control (MAGEC) rod, as well as easy maneuvering of the rod in either the cranial to caudal direction, we use a chest drain of size 24 French diameter as a tunnel. This allows surgeons to fit the nonflexible part of MAGEC rod in the middle of the deformity and cut to length passed through the chest drain from a cranial to caudal position and then chest drain is removed.

Results:

A total of 40 children with early-onset scoliosis had insertion of MAGEC rods using this technique. There were 21 female and 19 male patients. Early-onset scoliosis etiology is idiopathic in 20 patients, neuromuscular in 16 patients, and others in 4 patients. Median age across all groups was 7 years (range 4–13) at the time of surgery. Follow-up ranged from 11 to 56 months with a median of 24 months.

Conclusion:

The use of a chest drain during subfascial passage of magnetically controlled growing rod is a safe, reliable, reproducible novel technique. This shortens overall time of surgery in our experience.

Force Testing of Explanted Magnetically Controlled Growing Rods

STUDY DESIGN

Laboratory analysis of explanted MAGnetic Expansion Control (MAGEC) growing rods.

OBJECTIVE

The aim of this study was to measure the force produced by explanted MAGEC rods compared with new rods and assess the influence of clinical variables.

SUMMARY OF BACKGROUND DATA

MAGEC rods are increasingly used in early-onset scoliosis. Some data are available describing the structure of explanted MAGEC rods, but to date, no study has assessed their function.

METHODS

Explanted MAGEC rods were received from seven UK and one Danish center. The force produced by explanted rods on activation with the external remote controller was measured using a dedicated jig. Forces were compared with two unused rods as well as the manufacturer's defined standard (42 Ibf). Clinical variables were collected from contributing centers where possible and correlated with the force measurements.

RESULTS

Forty-five MAGEC rods from 25 cases were received for analysis. The mean age at insertion was 8.6 years and rods were in vivo for a mean of 2.7 years in predominantly dual rod constructs. Two unused MAGEC rods produced a mean force of 45.3 (0.25) and 50.2 (1.4) Ibf, above the manufacturer's stated standard. Of the 45 explanted rods, 10 (22%) produced force greater or equal to manufacturer's standard, mean 46.7 (2.7) Ibf. Six rods (13%) produced some force but less than the manufacturer's standard, mean 34.8 (3.6) Ibf. Twenty-nine rods (64%) produced no force. The duration the rods were in vivo was significantly negatively correlated with the force produced on testing (r = -0.63, P < 0.005). Of the 12 rods implanted longer than 38 months, none produced any force.

CONCLUSION

This is the first study of the force, and hence likely function, of explanted MAGEC rods. The majority of explanted rods produced no force, while others produced reduced force. These findings raise questions regarding the longevity of the implant and further clinical outcome studies are recommended.

LEVEL OF EVIDENCE

4.