Characterizing Use of Growth-friendly Implants for Early-onset Scoliosis: A 10-Year Update

Current Concepts in the Treatment of Early Onset Scoliosis

Despite many surgical advances in the treatment of early onset scoliosis (EOS) over the past two decades, this condition remains a challenge to address. While otherwise healthy children can have EOS, many of these patients have complicated comorbidities making proper treatment algorithms extraordinarily difficult. Non-operative measures can be successful when initiated early, but are many times utilized as a delay tactic until growth-friendly operative procedures can be safely performed. This article will summarize the current concepts in the treatment of EOS with a focus on the surgical advances that have recently been made.

Proximal foundation anchor variations and their correlation with unplanned return to the operating room (UPROR) in children with EOS treated with magnetically controlled growing rods (MCGR)

INTRODUCTION

The evolution of MCGR technique has led to modifications in the configuration of the proximal construct to decrease the incidence of implant-related complications (IRC) and revision surgeries. However, there is no data characterizing the performance of the most used configurations reducing the risk of complications.

METHODS

487 patients were identified from an international multicenter EOS database.

INCLUSION CRITERIA

EOS patients, primary dual MCGR, complete radiographs, and minimum of 2-year follow-up. 76 patients had incomplete X-rays, 5 had apical fusions, and 18 had inconclusive complications, leaving 388 patients for review. A digital spine template was created to document UIV; number of levels; number, type, and location of anchors; as well as implant configuration. First available postoperative and latest follow-up radiographs were reviewed by two senior surgeons and two spine fellows. UPROR due to IRC was defined as any change in proximal anchors between the postoperative and final follow-up radiographs.

RESULTS

The most common proximal construct configuration: UIV at T2 (50.0%) with 17.5% UPROR, followed by T3 (34.0%) with 12.1% UPROR; number of levels was three (57.1%) with 16.8% UPROR and two (26.0%) with 17.0% UPROR; number of proximal anchors was six (49.9%) with 14.1% UPROR and four (27.0%) with 18.3% UPROR. The most common anchors were all screws (42.0%) with 9.9% UPROR, and all hooks (26.4%) with 31.4% UPROR (P < 0.001). The construct with the lowest rate of UPROR was a UIV at T2, with six anchors (all screws) across three levels (42 cases), with 0% UPROR. Other construct combinations that yielded 0% UPROR rates were UIV of T3, six anchors (all screws) across three levels (25 cases), and a UIV of T3 with six anchors (screws and hooks) across three3 levels (9 cases).

CONCLUSION

Proximal anchor configuration impacts the incidence of UPROR due to IRC in MCGR. UIV at T2 and T3 compared to T4, and the use of all screws or combination of screws and hooks compared to all hooks were associated with a lower UPROR rate. The most common construct configuration was T2 UIV, three levels, six anchors, and all screws. The use of a combination of six anchors (screws or screws and hooks) across three levels with a UIV at T2 or T3 was associated with a lower UPROR rate. Additional research is needed to further evaluate the variables contributing to configuration selection and their association with IRC.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Prognostic Level III.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Unplanned return to the operating room (UPROR) occurs in 40% of MCGR patients at an average of 2 years after initial implantation

PURPOSE

This study calculated the rates of Unplanned Return to the Operating Room (UPROR) in early-onset scoliosis patients who had no previous spine surgery and underwent Magnetically Controlled Growing Rod (MCGR) implantation.

METHODS

We reviewed surgical, radiographic, and UPROR outcomes for EOS patients treated with the MCGR implant < 12 years + 11 months of age, had complete preop/postop major curve measurements, and had complete MCGR details.

RESULTS

376 patients underwent MCGR implantation at a mean age of 7.7 years (1.8-12.9). Diagnoses included 106 (28%) idiopathic, 84 (22%) syndromic, 153 (41%) neuromuscular, and 33 (9%) congenital. The mean preop-cobb was 76.7° (9-145°), and an immediate postop correction was 41% (0-84%). We found that 38% (142/376) of patients experienced an UPROR prior to the maximal actuator length being achieved. UPROR occurred at mean 2 years (3 days-5 years) after initial implantation. Of the 142 patients who experienced UPROR there were 148 complications that lead to an UPROR. The most common reason for UPROR was anchor (55/148: 37%) or MCGR implant related (33/148: 22%). Wound related (22/148:15%), Neuro related 4/148: 3%), and other (34/148: 23%) accounted for the remaining UPROR occurrences.

CONCLUSION

In conclusion, the MCGR UPROR rate was 142/376 (38%) after an average of 2 years post implantation. At 2-year follow-up, only 20% of MCGR patients had experienced an UPROR. However, between 2 and 5 years, the development of an UPROR increased precipitously with only 39% of MCGR patients remaining UPROR free at 5 years post MCGR implantation. The most common reason for UPROR was related to anchor or MCGR implant-related complications. This information can be utilized to set realistic expectations about the need and timing of future surgical procedures with patients and their families.

Do Rib-Based Anchors Impair Chest Wall Motion in Early Onset Scoliosis (EOS)?

Purpose

There is a concern in pediatric surgery practice that rib-based fixation may limit chest wall motion in early onset scoliosis (EOS). The purpose of this study is to address the above concern by assessing the contribution of chest wall excursion to respiration before and after surgery.

Methods

Quantitative dynamic magnetic resonance imaging (QdMRI) is performed on EOS patients (before and after surgery) and normal children in this retrospective study. QdMRI is purely an image-based approach and allows free breathing image acquisition. Tidal volume parameters for chest walls (CWtv) and hemi-diaphragms (Dtv) were analyzed on concave and convex sides of the spinal curve. EOS patients (1-14 years) and normal children (5-18 years) were enrolled, with an average interval of two years for dMRI acquisition before and after surgery.

Results

CWtv significantly increased after surgery in the global comparison including all EOS patients (p < 0.05). For main thoracic curve (MTC) EOS patients, CWtv significantly improved by 50.24% (concave side) and 35.17% (convex side) after age correction (p < 0.05) after surgery. The average ratio of Dtv to CWtv on the convex side in MTC EOS patients was not significantly different from that in normal children (p=0.78), although the concave side showed the difference to be significant.

Conclusion

Chest wall component tidal volumes in EOS patients measured via QdMRI did not decrease after rib-based surgery, suggesting that rib-based fixation does not impair chest wall motion in pediatric patients with EOS.

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.

Diagnostic and therapeutic strategies in early onset scoliosis: A current concept review

Substantial advances in the treatment of early onset scoliosis (EOS) over the past two to three decades have resulted in significant improvements in health-related quality of life of affected children. In addition to classifications that address the marked heterogeneity of this patient population, increasing understanding of the natural history of the disease, and new implants and treatment techniques have resulted in innovations unlike any other area of pediatric orthopedics. The growing understanding of the interaction between spinal and thoracic growth, as well as dependent lung maturation, has had a lasting impact on the treatment strategy of this potentially life-threatening disease. The previous treatment approach with early corrective fusion gave way to a growth-friendly concept. Despite the steady development of new growth-friendly surgical treatment options, whose efficacy still needs to be validated, as well as a revival of conservative growth control with serial casts and/or braces, the psychosocial burden of the long lasting and complication-prone treatments remains high. As a consequence, EOS still represents one of the greatest pediatric orthopedic challenges.

Failure to lengthen consensus for the magnetically controlled growing rod (MCGR)

INTRODUCTION

MCGR lengthening has become an important innovation in treating patients with EOS. An alternative to traditional growing instrumentation, a single surgical procedure is necessary for insertion of the construct, followed by non-invasive lengthening in the outpatient setting. With every new technology emanates a new complication to troubleshoot. Failure to lengthen in the MCGR is a significant cause of revision surgery. Currently, no consensus exists on how to define a MCGR lengthening failure, what steps are necessary after a failure to lengthen, and what factors determine these next steps. The primary goal of this study was to establish a consensus on how to define and navigate a MCGR that fails to lengthen.

METHODS

A series of 3 surveys were distributed to 49 early onset scoliosis surgeons with 37 responses between December 2021 and April 2022. Consensus was defined as at least 70% agreement.

RESULTS

37 of 49 surgeons (75%) responded to the first survey, and all 37 surgeons responded to the following two surveys (100%). Consensus statements were reached on 25% of questions (3/12) from survey 1, 40% of questions (4/10) on survey 2, and 100% of questions (5/5) on survey 3. The questions that reached consensus are detailed in Table 1. Consensus steps to navigate a rod that fails to lengthen 1 mm (97%) in the office include retrying during the same visit (78%), changing technique in the office (88%), and not adjusting the interval between lengthening appointments (78%). Table 1 Items that reached consensus from each survey (12 total) Survey Question Response, Consensus Percentage 1 If a rod does not lengthen, do you try again in that office visit?​ Yes, 78% 1 All modes of XR are equivalent when determining failure to lengthen? Yes, 70% 1 If you are unsuccessful at lengthening, you should change the lengthening interval? No, 78% 2 Re-lengthening a rod following a failure to lengthen one should change their technique? Yes, 88% Reposition patient, 100% Alternate rods, 90% No traction in OR, 92.6% 2 Is a MCGR non-operational following 3 consecutive visits where the rod failed lengthening? Yes, 100% 2 Considerations when determining next steps with a non-operational rod? Skeletal Age, 100% Curve Progression, 97% Curve Stiffness, 93.8% Family Convenience, 83% Chronologic Age, 77% Time from Last Lengthening, 70% 2 Can an APP follow your protocol for a rod that has failed to lengthen? Yes, 81% 3 Are you comfortable using either clunk or stall to describe the phenomena of the internal clutch failing within the actuator when lengthening? Yes, 97.3% 3 Clunk/stall try again before an adjustment? Yes, 81% 3 Define failure to lengthen? Less than 1 mm length achieved, 97% 3 After two failure to lengthen events do you discuss next surgical steps?​ Yes, 97% 3 Once a rod had been classified as non-operational (no longer lengthening despite interventions) do you consider the underlying diagnosis when making next step decisions? Yes, 97% CONCLUSION: Best clinical practice guidelines using a Delphi method established a consensus on defining failure to lengthen in a MCGR (less than 1 mm), appropriate responses to failure to lengthen (re-attempt to lengthen and re-position patient) and a definition for a non-functional MCGR (failure to lengthen 3 consecutive times). This consensus will help standardize research on this important problem.

LEVEL OF EVIDENCE

V-expert opinion.

Changes in sagittal balance and pre-existing junctional angle influence development of proximal junctional kyphosis in growth guidance systems for early-onset scoliosis

PURPOSE

Proximal junctional kyphosis (PJK) has been reported to occur at a rate of about 30% in traditional growing rods (GR) and magnetically controlled growing rods (MCGR). Growth guidance systems (GGS) have non-rigid, gliding fixation along rods, which may mitigate PJK. There have been no studies done in shilla around PJK, hence this study aimed to assess the occurrence, risk factors, and timeline of PJK.

METHODS

A prospective, multicenter database was queried for EOS patients who underwent surgery utilizing GGS.

INCLUSION CRITERIA

< 10 years at index surgery and > 2 year follow-up.

RESULTS

Sixty-five patients (thirty-six female) met inclusion criteria. Mean age at index surgery was 6.2 y/o (2-9); mean follow-up was 66 m. Most common etiologies were syndromic (n = 23). Mean thoracic kyphosis at pre-op was 41.8°, post-op was 35.5°, and final was 42.2°. Mean PJA at pre-op was 6.15°, post-op 1 was 4.2°, and final was 15.6°. Incidence of PJK at post-op was 35% and final was 43%. Pre-op sagittal balance and change in sagittal balance from pre-op to post-op were associated with post-op PJK (p = 0.05, 0.02). Change in spinal height from pre-op to post-op was associated with PJK at final (p = 0.04). Interestingly, increased PJA at pre-op was significantly associated with decreased PJK at post-op and final (p = 0.01, 0.03).

CONCLUSION

PJK was identified in 43% of patients post-operatively after GGS for EOS. Pre-op PJA was negatively correlated with an increased incidence of PJK. Changes in sagittal balance, in either direction, was the strongest predictor for development of PJK post-operatively.

Radiographic and clinical outcomes after definitive spine fusion for skeletally immature patients with idiopathic scoliosis

PURPOSE

To assess the intermediate-term radiographic and clinical outcomes of skeletally immature idiopathic scoliosis (IS) patients that underwent definitive fusion (DF).

METHODS

A retrospective review of patients with IS who were Risser 0 with open tri-radiate cartilages at the time of DF with minimum 5-year follow-up. Outcomes included Scoliosis Research Society (SRS)-30 scores, major Cobb angle, pulmonary function tests (PFTs), and unplanned returns to the operating room (UPROR). Adding-on was defined as progression of the major Cobb angle > 5° or tilt of the lowest instrumented vertebra > 5°.

RESULTS

Thirty-two patients (78% female, mean age 12.2 ± 1.3 years old, mean preoperative major Cobb 64.8° ± 15.9) were included. Of these patients, 20 (62.5%) experienced adding-on and 6 (18.8%) required a revision surgery to correct their progressive spinal deformity. Adding-on was associated with lower 5-year postoperative SRS scores for appearance (3.7 ± 0.7 vs 4.4 ± 0.3, p = 0.0126), mental health (4.2 ± 0.6 vs 4.6 ± 0.3, p = 0.0464), satisfaction with treatment (4.0 ± 0.8 vs 4.7 ± 0.4, p = 0.0140), and total score (4.0 ± 0.4 vs 4.4 ± 0.2, p = 0.0035). The results of the PFTs did not differ between groups. Patients experienced an average of 0.53 UPROR/patient.

CONCLUSION

DF in skeletally immature patients results in a high rate of adding-on, which adversely affects Health-Related Quality of Life. However, reoperation rates, both planned and unplanned, remain lower when compared to patients undergoing growth-friendly treatment.

Rib-to-spine and rib-to-pelvis magnetically controlled growing rods: does the law of diminishing returns still apply?

PURPOSE

The Law Of Diminishing Returns (LODR) has been demonstrated for traditional growing rods, but there is conflicting data regarding the lengthening behavior of Magnetically Controlled Growing Rods (MCGR). This study examines a cohort of patients with early-onset scoliosis (EOS) with rib-to-spine or rib-to-pelvis-based MCGR implants to determine if they demonstrate the LODR, and if there are differences in lengthening behaviors between the groups.

METHODS

A prospectively collected multicenter EOS registry was queried for patients with MCGR with a minimum 2-year follow-up. Patients with rib-based proximal anchors and either spine- or pelvis-based distal anchors were included. Patients with non-MCGR, unilateral constructs, < 3 lengthenings, or missing > 25% datapoints were excluded. Patients were further divided into Primary-MCGR (pMCGR) and Secondary-MCGR (sMCGR).

RESULTS

43 rib-to-spine and 31 rib-to-pelvis MCGR patients were included. There was no difference in pre-implantation, post-implantation and pre-definitive procedure T1-T12 height, T1-S1 height, and major Cobb angles between the groups (p > 0.05). Sub-analysis was performed on 41 pMCGR and 19 sMCGR rib-to-spine patients, and 31 pMCGR and 17 sMCGR rib-to-pelvis patients. There is a decrease in rod lengthenings achieved at subsequent lengthenings for each group: rib-to-spine pMCGR (rho = 0.979, p < 0.001), rib-to-spine sMCGR (rho = 0.855, p = 0.002), rib-to-pelvis pMCGR (rho = 0.568, p = 0.027), and rib-to-pelvis sMCGR (rho = 0.817, p = 0.007). Rib-to-spine pMCGR had diminished lengthening over time for idiopathic, neuromuscular, and syndromic patients (p < 0.05), with no differences between the groups (p > 0.05). Rib-to-pelvis pMCGR neuromuscular patients had decreased lengthening over time (p = 0.01), but syndromic patients had preserved lengthening over time (p = 0.65).

CONCLUSION

Rib-to-spine and rib-to-pelvis pMCGR and sMCGR demonstrate diminished ability to lengthen over subsequent lengthenings.

Beyond the gut: spectrum of magnetic surgery devices

Since the 1970s, magnetic force has been used to augment modern surgical techniques with the aims of minimizing surgical trauma and optimizing minimally-invasive systems. The majority of current clinical applications for magnetic surgery are largely centered around gastrointestinal uses-such as gastrointestinal or bilioenteric anastomosis creation, stricturoplasty, sphincter augmentation, and the guidance of nasoenteric feeding tubes. However, as the field of magnetic surgery continues to advance, the development and clinical implementation of magnetic devices has expanded to treat a variety of non-gastrointestinal disorders including musculoskeletal (pectus excavatum, scoliosis), respiratory (obstructive sleep apnea), cardiovascular (coronary artery stenosis, end-stage renal disease), and genitourinary (stricture, nephrolithiasis) conditions. The purpose of this review is to discuss the current state of innovative magnetic surgical devices under clinical investigation or commercially available for the treatment of non-gastrointestinal disorders.

Update on the Diagnosis and Management of Early-onset Scoliosis

PURPOSE OF REVIEW

In this article, we review the most recent advancements in the approaches to EOS diagnosis and assessment, surgical indications and options, and basic science innovation in the space of early-onset scoliosis research.

RECENT FINDINGS

Early-onset scoliosis (EOS) covers a diverse, heterogeneous range of spinal and chest wall deformities that affect children under 10 years old. Recent efforts have sought to examine the validity and reliability of a recently developed classification system to better standardize the presentation of EOS. There has also been focused attention on developing safer, informative, and readily available imaging and clinical assessment tools, from reduced micro-dose radiographs, quantitative dynamic MRIs, and pulmonary function tests. Basic science innovation in EOS has centered on developing large animal models capable of replicating scoliotic deformity to better evaluate corrective technologies. And given the increased variety in approaches to managing EOS in recent years, there exist few clear guidelines around surgical indications across EOS etiologies. Despite this, over the past two decades, there has been a considerable shift in the spinal implant landscape toward growth-friendly instrumentation, particularly the utilization of MCGR implants. With the advent of new biological and basic science treatments and therapies extending survivorship for disease etiologies associated with EOS, the treatment for EOS has steadily evolved in recent years. With this has come a rising volume and variation in management options for EOS, as well as the need for multidisciplinary and creative approaches to treating patients with these complex and heterogeneous disorders.

Surgical Treatment of Spinal Deformities in Pediatric Orthopedic Patients

Scoliosis and Scheuermann's disease are common spinal deformities that affect a substantial population, particularly adolescents, often impacting their quality of life. This comprehensive review aims to present a detailed understanding of these conditions, their diagnosis, and various treatment strategies. Through an extensive exploration of current literature, the review discusses the etiology of these spinal deformities and the use of diagnostic tools such as X-rays and MRI. It further delves into the range of treatment options available, from conservative approaches such as physiotherapy and bracing to more invasive surgical interventions. The review underscores the necessity of an individualized treatment approach, taking into account factors such as the patient's age, the severity of the curvature, and overall health. This all-encompassing perspective on scoliosis and Scheuermann's disease will aid in evidence-based decision making in their management with the goal of improving patient outcomes.

Changes in research quality and surgical trends at the international congress on early-onset scoliosis

PURPOSE

The founding of the International Congress for Early Onset Scoliosis (ICEOS) and first annual meeting in 2007 represented a significant milestone in advancing the care of patients with EOS. Due to the complexity and rarity of EOS, this annual conference is the premiere venue for physicians, researchers, and advanced practice providers to identify and understand the best treatments for children with EOS. This study examines the trend of various treatment modalities presented at ICEOS and the changes in research quality since its inception.

METHODS

Podium presentations from the 2007 through 2021 ICEOS annual meetings were reviewed to determine the number of study patients, use of a study group, and key features of study design. Treatment strategies being evaluated were recorded and included non-operative treatments (casting/bracing), traditional growing rods (TGR), vertical expandable prosthetic titanium rib (VEPTR), Shilla growth guidance, magnetically controlled growing rods (MCGR), and vertebral body tethering (VBT). Linear regressions were performed to analyze changes in research topic and study group utilization.

RESULTS

A total of 532 abstracts were reviewed. An average of 97.5 ± 81.3 patients were included per study with a significant increase from 42.3 ± 89.7 in 2007 to 337.6 ± 587.4 in 2021 (r² = 0.632, p < 0.001). A total of 130 (24.4%) abstracts resulted from multicenter study groups with the proportion increasing significantly from 13.0% in 2007 to 36.4% in 2021 (p = 0.039, r² = 0.289). The majority (96.2%) of study group-based projects were from either the Growing Spine Study Group (GSSG), Chest Wall and Spine Deformity Study Group (CWSDG), Children's Spine Study Group (CSSG), or the Pediatric Spine Study Group (PSSG). Additionally, a significant increase in studies utilizing patient-reported outcome measures (PROMs) was observed (r² = 0.336, p = 0.023). Significant increases in the proportion of presentations discussing MCGR (r² = 0.738, p < 0.001) and VBT (r² = 0.294, p = 0.037) as surgical treatments were observed.

CONCLUSION

The trends in EOS device implantation observed in registry studies align with the trends in research presented at ICEOS including the increased proportion of studies focusing on MCGR and VBT over the past decade. An attempt to increase the quality of research presented at ICEOS through multicenter study groups, increased patient recruitment, and utilization of PROMs has been seen since its inception.

LEVEL OF EVIDENCE

V.

Risk of ventriculoperitoneal shunt malfunction in operatively treated early onset spinal deformity

PURPOSE

Ventriculoperitoneal (VP) shunt placement is a common neurosurgical procedure performed in patients with early onset scoliosis (EOS). To provide insight into the risks of spine lengthening operations, we investigate the rate of VP shunt complications in patients with EOS undergoing spinal deformity correction interventions.

METHODS

A retrospective review was performed of all patients with EOS at a single institution undergoing spinal deformity correction procedures from 2007 to 2018. Patients having undergone VP shunt implantation prior to deformity correction were included. A minimum of 2-year follow-up was required for inclusion. Clinical records and imaging studies were reviewed.

RESULTS

Nineteen patients with VP shunts underwent Vertical Expandable Prosthetic Titanium Rib (VEPTR) implantation for treatment of early onset spinal deformity. The mean age at shunt placement and spine instrumentation surgery was 13.7 months (1 day to 13 years) and 6.1 years (0.5-15.1) respectively. The diagnoses associated with shunt implantation were: 12 spina bifida, 3 structural defects or obstructions, 2 intraventricular hemorrhage, 1 cerebral palsy, and 1 campomelic dwarfism. During the first 2 years following rib-based insertion, there was a mean of 2.5 expansion/revision procedures (0-5) with no shunt-related complications. The mean length of follow-up in this series was 7.0 years (2.6-13.2). A total of three (16%) patients required shunt revision following their rib-based device insertion, two patients with proximal shunt malfunctions and one with a mid-catheter breakage, at 2.4, 2.6, and 5.6 years, respectively, after rod implantation (Fig. 2). Each of these shunt revisions occurred more than 50 days following an expansion procedure (1.9, 2.9, and 5.7 months, respectively).

CONCLUSION

Growing instrumentation procedures in EOS are associated with low risk for post-operative shunt complications in patients with ventriculoperitoneal shunts. There were no shunt revision procedures performed in the first 2 years following rib-based device insertion. Sixteen percent of patients went on to require a shunt revision at some point during their follow-up, which is comparable to the baseline rate of shunt revision in non-EOS patients.

LEVEL OF EVIDENCE

IV, Case series.

Contraindications to magnetically controlled growing rods: consensus among experts in treating early onset scoliosis

PURPOSE

The purpose of this study was to describe contraindications to the magnetically controlled growing rod (MCGR) in patients with early onset scoliosis (EOS) by establishing consensus amongst expert surgeons who treat these patients frequently.

METHODS

Nine pediatric spine surgeons from an international EOS study group participated in semi-structured interviews via email to identify factors that influence decision making in the use of MCGR. A 39-question survey was then developed to specify these factors as contraindications for MCGR-these included patient age and size, etiology, medical comorbidities, coronal and sagittal curve profiles, and skin and soft tissue characteristics. Pediatric spine surgeons from the EOS international study group were invited to complete the survey. A second 29-item survey was created to determine details and clarify results from the first survey. Responses were analyzed for consensus (> 70%), near consensus (60-69%), and no consensus/variability (< 60%) for MCGR contraindication.

RESULTS

56 surgeons of 173 invited (32%) completed the first survey, and 64 (37%) completed the second survey. Responders had a mean of over 15 years in practice (range 1-45) with over 6 years of experience with using MCGR (range 2-12). 71.4% of respondents agreed that patient size characteristics should be considered as contraindications, including BMI (81.3%) and spinal height (84.4%), although a specific BMI range or a specific minimum spinal height were not agreed upon. Among surgeons who agreed that skin and soft tissue problems were contraindications (78.6%), insufficient soft tissue (98%) and skin (89%) to cover MCGR were specified. Among surgeons who reported curve stiffness as a contraindication (85.9%), there was agreement that this curve stiffness should be defined by clinical evaluation (78.2%) and by traction films (72.3%). Among surgeons who reported sagittal curve characteristics as contraindications, hyperkyphosis (95.3%) and sagittal curve apex above T3 (70%) were specified. Surgeons who indicated the need for repetitive MRI as a contraindication (79.7%) agreed that image quality (72.9%) and not patient safety (13.6%) was the concern. In the entire cohort, consensus was not achieved on the following factors: patient age (57.4%), medical comorbidities (46.4%), etiology (53.6%), and coronal curve characteristics (58.9%).

CONCLUSION

Surgeon consensus suggests that MCGR should be avoided in patients who have insufficient spinal height to accommodate the MCGR, have potential skin and soft tissue inadequacy, have too stiff a spinal curve, have too much kyphosis, and require repetitive MRI, particularly of the spine. Future data-driven studies using this framework are warranted to generate more specific criteria (e.g. specific degrees of kyphosis) to facilitate clinical decision making for EOS patients.

LEVEL OF EVIDENCE

Level V-expert opinion.

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.

Optimizing Expansion Clinic for Patients With Magnetic Controlled Growth Rods

In 2017, members of the Pediatric Spine Study Group reported that 80% of new growth-friendly implants inserted were magnetically controlled growing rods (MCGRs). MCGRs are usually expanded more often than every 6 months, as was general practice with traditional growth rods. The growing volume of expansion visits is managed variably at different centers. Although there is existing research comparing MCGRs with traditional systems for efficacy and complications, there is limited literature regarding how expansion clinics are managed. This article reviews current practices such as scheduling, expansion verification, billing, and other key parameters for running expansion clinics.

[Nonfusion procedures in pediatric scoliosis]

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

Cost-Utility Analysis of Anterior Vertebral Body Tethering versus Spinal Fusion in Idiopathic Scoliosis from a US Integrated Healthcare Delivery System Perspective

Purpose

Anterior vertebral body tethering (VBT) is a non-fusion, minimally invasive, growth-modulating procedure with some early positive clinical outcomes reported in pediatric patients with idiopathic scoliosis (IS). VBT offers potential health-related quality of life (HRQoL) benefits over spinal fusion in allowing patients to retain a greater range of motion after surgery. We conducted an early cost-utility analysis (CUA) to compare VBT with fusion as a first-choice surgical treatment for skeletally immature patients (age >10 years) with moderate to severe IS, who have failed nonoperative management, from a US integrated healthcare delivery system perspective.

Patients and Methods

The CUA uses a Markov state transition model, capturing a 15-year period following index surgery. Transition probabilities, including revision risk and subsequent fusion, were based on published surgical outcomes and an ongoing VBT observational study (NCT02897453). Patients were assigned utilities derived from published patient-reported outcomes (PROs; SRS-22r mapped to EQ-5D) following fusion and the above VBT study. Index and revision procedure costs were included. Probabilistic (PSA) and deterministic sensitivity analyses (DSA) were performed.

Results

VBT was associated with higher costs but also higher quality-adjusted life years (QALYs) than fusion (incremental costs: $45,546; QALYs gained: 0.54). The subsequent incremental cost-effectiveness ratio for VBT vs fusion was $84,391/QALY gained. Mean PSA results were similar to the base case, indicating that results were generally robust to uncertainty. The DSA indicated that results were most sensitive to variations in utility values.

Conclusion

This is the first CUA comparing VBT with fusion in pediatric patients with IS and suggests that VBT may be a cost-effective alternative to fusion in the US, given recommended willingness-to-pay thresholds ($100,000–$150,000). The results rely on HRQoL benefits for VBT compared with fusion. For improved model accuracy, further analyses with longer-term PROs for VBT, and comparative effectiveness studies, would be needed.