The Shilla growth guidance technique for early-onset spinal deformities at 2-year follow-up: a preliminary report

Shilla Growth Guidance Surgery for Early Onset Scoliosis: Predictors of Optimal Versus Suboptimal Performers

BACKGROUND

The Shilla Growth Guidance surgery (SGGS) aims to correct a child's spinal deformity while allowing continued spinal growth. Our study used a multicenter early-onset-scoliosis database to determine significant predictors of best candidates.

METHODS

The Pediatric Spine Study Group multicenter database was analyzed for all patients who had undergone SGGS and had a minimum follow-up of 2 years. Patients without radiographic measurements preoperatively, postoperatively, and at the latest follow-up, as well as patients with myelo gibbus deformities, were excluded. These radiographs were evaluated for major curve, spinal length, and other parameters. Multivariate regressions were conducted to assess the effects of these parameters on the following 4 outcomes: (1) percent of initial curve correction, (2) scoliosis curve progression after surgery per year, (3) at least 1 unplanned SGGS-related reoperation, and (4) T1-S1 height change per year from 1st postoperative erect to final available follow-up.

RESULTS

Included were 105 children; the average follow-up was 4.8±2.4 years. Scoliosis etiologies included neuromuscular (n=36; 34%), syndromic (n=31; 30%), idiopathic (n=30; 29%), and congenital (n=8; 8%). Average preoperative, 1st postoperative erect, and latest follow-up major curves measured 69, 32, and 49 degrees, respectively. Average T1-S1 postoperative height change per year was 7±9 mm and average overall T1-S1 height change was 24±35 mm. Forty-eight (46%) patients had C-shaped and 57 (54%) had S-shaped curves; 59 (56%) patients underwent ≥1 SGGS-related reoperation. Multivariate Cox-proportional hazard test revealed younger age at index surgery [hazard ratio (HR)=0.83, P=0.028] and S-shaped curves (HR=0.43, P=0.014) were associated with ≥1 reoperation. Further analysis revealed age younger than 7 years (HR=0.48, P=0.021) was correlated with an increased risk of SGGS-related reoperation. The preoperative major curve was not significantly associated with any outcome measure. A reoperation-free survival rate of 50% corresponded to 3.5 years.

CONCLUSION

SGGS instrumentation in patients younger than 7 years and patients with an S-shaped curve were associated with SGGS-related unplanned surgical interventions. Despite younger age being associated with likely complications, this procedure still benefits these children and provides significant curve correction while allowing growth.

LEVEL OF EVIDENCE

Level III.

A Novel Dynamic Growth Rod Inducing Spinal Growth Modulation for the Correction of Spinal Deformities

Background

Growth rods are the gold standard for treating early-onset scoliosis (EOS). However, current treatments with growth rods do not optimize spinal growth in EOS patients, and frequent distraction surgeries significantly increase complications, imposing considerable economic and psychological burdens on patients. An improved growth rod is urgently required to address the need for dynamic growth and external regulation.

Methods

This study designed a novel growth rod (NGR) with unidirectional sliding and external regulation capabilities. By establishing a three-dimensional model of the EOS spine, we simulated the implantation of traditional growth rods (TGR) and NGR. We applied a compressive load of 400 N to test axial stiffness and a moment of 1 NM to assess bending stiffness under six different conditions. Additionally, we evaluated the range of motion (ROM) of the spinal joints, and the distribution of Von Mises stress in vertebrae, intervertebral discs, and the growth rods, and calculated the axial force, moment, fatigue life, and strain energy of the device.

Results

NGR exhibits higher axial compression and torsional stiffness than TGR and the Intact group. Additionally, Von Mises stress values for NGR are higher than those for TGR across all operating conditions, albeit with slightly lower total strain energy than TGR. Although Von Mises stress in NGR concentrates near the screw fixation, the fatigue life remains adequate for basic living requirements.

Conclusion

Overall, NGR demonstrates superior stiffness and stress distribution. NGR's distraction-based implant features a unidirectional sliding component with a spring-driven mechanism for dynamic correction and a novel non-invasive extension mechanism to reduce infections. Compared to leading EOS implants, NGR offers improved stability, showing promise for enhancing EOS surgical interventions.

Breaking the "law of diminishing returns" with novel, staged, unilateral magnetically controlled growing rods to guided growth surgery for severe, progressive infantile scoliosis

PURPOSE

Infantile scoliosis presents a significant challenge due to high risk of pulmonary complications and morbidity. While dual growing rod constructs are often utilized, they are not always feasible in a young patient with a severe curve. In this study, we present a series of eight patients treated with a unilateral magnetically controlled growing rod (uMCGR) construct later converted to guided growth surgery (GGS).

METHODS

A multicenter database was queried for patients with progressive infantile scoliosis treated with uMCGR before later conversion to GGS. A minimum of 2 year follow-up was required for inclusion. Curve magnitude, trunk growth, revisions, and complications were tracked at all time points.

RESULTS

Eight patients were included in the study. Mean age at index surgery was 4.1 years, while conversion to GGS occurred at average 7.9 years and final follow-up was at 10.5 years of age. At index procedure, major curve averaged 77.1°, which improved to 45.4°. Major curve increased to 48.4° prior to conversion, then improved to 30.9°. Major curve averaged 36.8° at final follow-up, for a maintained curve correction of 52.3%. T1-12 height and T1-S1 height averaged 15.4 and 21.5 cm at index procedure and increased to 20.6 and 32.7 cm at final follow-up. Nine revisions were performed in 6 patients, and no patient showed evidence of premature fusion.

CONCLUSIONS

Treatment of severe progression infantile scoliosis with this staged protocol provided excellent curve correction with continued trunk growth through treatment, without evidence of the "Law of Diminishing Returns".

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.

A novel approach to surgical treatment of adolescent idiopathic scoliosis in skeletally immature patients

Purpose

Describe the surgical technique and experience using the LSZ growing system in skeletally immature patients for two-stage surgical treatment of adolescent idiopathic scoliosis (AIS).

Methods

Eleven skeletally immature patients who underwent two-stage surgical treatment of AIS in our center were retrospectively analyzed. Patients initially treated with the LSZ growing system were observed for an average of 40.5 months (range 23-64 months) and for 4 years after planned replacement of the LSZ growing system with a standard pedicle screw system.

Results

The average preoperative angle of the main thoracic curve was 64.55 ± 3.21°, and that of the lumbar curve was 46 ± 5.52°. After instrumentation using the LSZ growing system, the thoracic curve was corrected to 17.63 ± 5.14°, and the lumbar curve to 9.2 ± 5.45°. The correction percentages were 72.52 ± 8.35 and 80.59 ± 10.77, respectively. After planned replacement of the LSZ system with a pedicle screw system, the angle of the thoracic curve changed to 11.45 ± 4.84°, and the lumbar curve to 6.4 ± 4.72°. The percentages of final correction were 82,1 ± 7,91 and 85,64 ± 5,47, respectively. The difference in the "LSZ growth coefficient" was 0.063 ± 0.037, which indicates continued growth of the spine along the instrumented region. None of the patients had neurological or infectious complications.

Conclusion

Our study demonstrates the safety and effectiveness of 2-stage treatment of AIS using the LSZ system, which allows for spine growth during the period between stages.

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.

The efficacy of bracing in the treatment of progressive early-onset scoliosis

Serial casting as one of the applications to treat early-onset scoliosis has been reported efficiently to improve deformity, but no report has focused on the efficacy of braces in the treatment of congenital early-onset scoliosis and comparison with progressive idiopathic early-onset scoliosis. Patients with progressive EOS treated with braces in our institution with a minimum of 4 years follow-up were reviewed. Two groups according to the etiological diagnosis were analyzed and compared: the congenital scoliosis (CS) group and idiopathic scoliosis (IS) group. The success cases and the failure cases were also compared. 27 patients with an average main Cobb angle of 38.19° (20-55) underwent initial bracing at an average age of 55.7 months (24-108), the average follow-up time was 76.19 months (49-117). In IS group the main Cobb angle was corrected to 18.69 ± 12.06° (48.61%) following the first bracing; the final Cobb angle was 23.08 ± 22.15°(38.76%) after brace removal. In CS group the main Cobb angle was corrected to 33.93 ± 10.31°(17.1%) following the first bracing and 37.93 ± 14.74°(3.53%) after brace removal. Both coronal chest width and T1-T12 height increased dramatically from pre-bracing to the last follow-up. Patients diagnosed as IS tended to have a better result in main Cobb angle correction than that of CS (P = 0.049). By the time of last follow-up, 8 patients had undergone surgery, and the operation time was postponed by 68.88 ± 26.43 months. For patients with progressive early-onset scoliosis, bracing is an efficient nonsurgical alternative to casting, and some of them can be cured; if not, eventual surgical intervention can be delayed for a period of time without restrictions on the thoracic cavity.

A Novel growth guidance system for early onset scoliosis: a preliminary in vitro study

PURPOSE

The purpose of the study was to describe a novel growth guidance system, which can avoid metal debris and reduce the sliding friction forces, and test the durability and glidability of the system by in vitro test.

METHOD

Two major modifications were made to the traditional Shilla system, including the use of ultra-high molecular weight polyethylene (UHMWPE) gaskets to avoid direct contact between the screw and rod, and polishing the surface of the sliding part of the rod. We tested the durability of the system by a fatigue test, which the samples were test on the MTS system for a 10 million cycle of a constant displacement. Pre and post-testing involved weighing the UHMWPE gaskets and observing the wear conditions. The sliding ability were measured by a sliding displacement test. The maximum sliding displacement of the system was measured after a 300 cycles of dynamic compressive loads in a sinusoidal waveform.

RESULTS

After the fatigue test, all the UHMWPE gaskets samples showed some of the fretting on the edge of the inner sides, but its still isolated and avoided the friction between the screws and rods. There was no production of metallic fretting around the sliding screws and rods. The average wear mass of the UHMWPE gaskets was 0.002 ± 0.001 g, less than 1.7% of the original mass. In the sliding test, the novel growth guidance system demonstrated the best sliding ability, with an average maximum sliding distance(AMSD) of 35.75 ± 5.73 mm, significantly better than the group of the traditional Shilla technique(AMSD 3.65 ± 0.46 mm, P < 0.0001).

CONCLUSION

In conclusion, we modified the Shilla technique and designed a novel growth guidance system by changing the friction interface of sliding screw and rod, which may significantly reduce the metallic debris and promote spine growth. The fatigue test and sliding dislocation test demonstrated the better durability and glidability of the system. An in vivo animal experiment should be performed to further verify the system.

A novel growth-friendly system alleviates pulmonary dysplasia in early-onset scoliosis combined with thoracic insufficiency syndrome: Radiological, pathological, and transcriptomic assessments

Background

The posterior procedure utilizing growth-friendly techniques is the golden standard for patients with early-onset scoliosis combined with thoracic insufficiency syndrome (EOS + TIS). Pulmonary hypoplasia is the main cause of dying prematurely in the EOS + TIS. This study assessed the therapeutic impact of a novel growth-friendly system on the pulmonary development of piglet's EOS + TIS model.

Methods

The animal procedure period lasts 12 weeks, of which the construction of the EOS + TIS was performed at 0-8 weeks, and implantation of a novel growth-friendly system was applied at 8-12 weeks. During the animal procedure, X-rays and CT were performed to observe scoliosis, thorax, and lungs. After 12 weeks, pathological changes in lung tissue were assessed using HE and IHC staining. RNA-seq characterized novel growth-friendly system-associated differentially expressed genes (DEGs) and validated using RT-qPCR, western blotting, and IHC.

Results

Implantation of the novel growth-friendly system increased body weight, body length, and total lung volume, as well as decreased the coronal and sagittal Cobb angles for the EOS + TIS model. It also ameliorated EOS + TIS-induced thickening of the alveolar wall, increased alveolar spaces, and decreased alveolar number and diameter. In lung tissue, a total of 790 novel growth-friendly system-associated DEGs were identified, and they were mainly involved in the regulation of immune, inflammatory, calcium transport, and vascular development. Among these DEGs, BDKRB1, THBS1, DUSP1, IDO1, and SPINK5 were hub genes, and their differential expression was consistent with RNA-seq results in lung tissues.

Conclusion

The novel growth-friendly system has mitigated scoliosis and pulmonary hypoplasia in the EOS + TIS model. We further elucidate the molecular mechanisms underlying the amelioration of pulmonary hypoplasia.

Dual Growing Rods and the Apical Control Technique for Treating Congenital Early-Onset Scoliosis: Lessons Learned

BACKGROUND

Congenital early-onset scoliosis (CEOS) is characterized by a spectrum of vertebral anomalies, including formation failures and segmentation failures at the apex segment, which makes CEOS different from other etiologies of early-onset scoliosis. To date, studies on patients who have graduated from CEOS treatment using traditional dual growing rods (TDGR) have been scarce, and the preliminary results of TDGR with or without the apical control technique (ACT) have varied. We therefore compared the final outcomes of patients with CEOS who graduated from TDGR with or without the ACT.

METHODS

A retrospective study of patients with CEOS who had graduated from TDGR treatment performed from 2007 to 2020 was conducted. Graduation included final fusion or observation after reaching skeletal maturity. Patients were divided into the ACT-TDGR group (apical vertebrectomy and/or hemivertebrectomy with short fusion and TDGR) and the TDGR-only group. Demographic characteristics, radiographic data, patient-reported clinical outcomes, pulmonary function, and complications were analyzed.

RESULTS

A total of 41 patients with CEOS were enrolled: 13 in the ACT-TDGR group and 28 in the TDGR-only group. The lengthening intervals were longer in the ACT-TDGR group (mean [and standard deviation], 1.26 ± 0.66 years) than in the TDGR-only group (0.80 ± 0.27 years). The preoperative main curve was larger in the ACT-TDGR group (80.53° ± 19.50°) than in the TDGR-only group (64.11° ± 17.50°). The residual curve was comparable between groups (26.31° ± 12.82° in the ACT-TDGR group compared with 27.76° ± 15.0° in the TDGR group) at the latest follow-up. The changes in apical vertebral rotation and thoracic rotation were significantly larger in the ACT-TDGR group. Patients had comparable T1-12 and T1-S1 heights, pulmonary function, and 22-item Scoliosis Research Society (SRS-22) scores at the latest follow-up. The mean number of mechanical-related complications per patient was lower in the ACT-TDGR group (0.77 ± 0.73) than in the TDGR-only group (1.54 ± 1.43). Seventeen patients underwent final fusion.

CONCLUSIONS

In this small-scale study, we observed that both ACT-TDGR and TDGR-only could correct the deformity while allowing for spinal growth in patients with CEOS. ACT-TDGR yielded better correction in severe cases and did not have a deleterious effect on spinal height. A large number of cases will be needed to validate the clinical value of the ACT.

LEVEL OF EVIDENCE

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

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.

The Generational Differences in Growth-Friendly Treatment Utilization for Early-Onset Scoliosis

Background: The development of new growth-friendly techniques for treating early-onset scoliosis (EOS) has resulted in a rapidly changing landscape of available treatment strategies. There is no literature revealing how a surgeon's years in practice (YIP) is related to the EOS techniques they learned in fellowship and how their YIP influences their decision-making in selecting EOS constructs. The purpose of this study was to assess how a surgeon's fellowship training and their years in practice (YIP) might affect which treatments they use in practice as well as attempt to gain insight into their decision-making process for such treatments. Methods: A 25-question survey was electronically delivered to 144 surgeons who treat EOS, and 87 (60%) responded. Surgeons were divided into two groups: a younger group (YG) with 0-10 YIP and an older group (OG) with >10 YIP. Growth-friendly techniques queried included serial casting, traditional growing rods (TGR), Vertical Expandable Prosthetic Titanium Rib (VEPTR), non-VEPTR rib constructs, Magnetically Controlled Growing Rods (MCGR), and Shilla. A Chi-square analysis was used to determine differences between the YIP groups with regard to which techniques surgeons learned in fellowship and which techniques they use in practice. Results: One hundred percent (38/38) of the YG surgeons were fellowship-trained versus 87.8% (43/49) of the OG surgeons. More YG versus OG surgeons received fellowship training in serial casting (84.2% vs. 38.8%, p<0.001), TGR (94.7% vs. 63.3%, p<0.001), VEPTR (65.8% vs. 28.6, p<0.001), non-VEPTR rib constructs (55.3% vs. 16.3%, p<0.001), and MCGR (47.4% vs. 2%, p<0.001). OG surgeons were more likely to use TGR in the last 3 years, with 26% of YG versus 6% of OG surgeons never utilizing TGR and 5% of YG versus 31% of OG surgeons performing TGR cases > 10 times (p=.004). Regarding treatment preferences, more YG surgeons (84.2% vs. 39.6%, p<0.001) preferred to delay intervention until final fusion rather than use any growth-friendly techniques. Furthermore, YG surgeons see a limited need for growth-friendly constructs other than MCGR. Conclusions: YG surgeons were more likely to learn growth-friendly techniques in fellowship than OG surgeons, though in their practices, the groups use growth-friendly techniques at similar rates. Compared to OG surgeons, YG surgeons prefer performing definitive fusions over utilizing any growth-friendly surgical techniques. Key Concepts•The landscape of treatment options for early-onset scoliosis has changed significantly over the past few decades.•Aside from younger surgeons' proclivity to use magnetically controlled growing rods at higher rates than older surgeons, the two groups reported using other growth-friendly treatments at similar frequencies.•Younger surgeons were more likely than older surgeons to prefer waiting to perform a single definitive fusion rather than using a growth-friendly technique to treat early-onset scoliosis.

Novel dual: rod plate system for EOS improves vertebral wedging and permits spinal growth

BACKGROUND

To determine whether single-stage, growth-friendly instrumentation with a plate-rod spinal system (PRSS) can substantially correct the deformity of EOS at surgery and continue to rectify the deformity throughout the growth period.

METHODS

An observational study of 35 children with EOS treated by PRSS between February 2000 and October 2010 during a mean follow-up of 72 months. The mean age at surgery was 7 years. X-rays were taken preoperatively and postoperatively and at each follow-up. The Cobb angle, the apical vertebral wedge angle (AVWA), remaining rod lengths, maximal thoracic kyphosis and total T1-S1 heights were measured and compared.

RESULTS

Thirty-one patients, 9 boys and 22 girls, with a mean age of 7 years were completed follow-up. The Cobb angle changed from 64° to 36° after initial surgery and 26° at the last follow-up. The mean AVWA was 15° postoperatively and 5° at the last follow-up. The mean rod tail reserve length decreased from 53 mm immediately after surgery to 12 mm at the last follow-up. The mean preoperative maximum thoracic kyphosis was 41° and changed to 35° and 30° postoperatively and at latest follow-up, respectively. The mean preoperative T1-S1 height for all 32 patients was 52 mm acute lengthening and 122 mm of lengthening by the end of follow-up, respectively.

CONCLUSION

The PRSS provided immediate correction of most of the deformity at surgery and continued to rectify remaining scoliosis during the growth period. AVWA may be a useful method for monitoring the function of the PRSS in EOS.

Dual Growing Rods Combined With the Apical Convex Control Pedicle Screw Technique Versus Traditional Dual Growing Rods for the Surgical Treatment of Early-Onset Scoliosis: A Case-Matched 2-Year Study

BACKGROUND

Combination of apical control convex pedicle screws (ACPS) with traditional dual growing rods (TDGRs) had better apex control ability for early-onset scoliosis (EOS); however, there is a paucity of studies on the ACPS technique.

OBJECTIVE

To compare 3-dimensional deformity correction parameters and complications between the apical control technique (DGR + ACPS) and TDGR in the treatment of EOS.

METHODS

A retrospective case-match analysis consisting of 12 cases of EOS treated with the DGR + ACPS technique (group A) from 2010 to 2020, and matched with TDGR case (group B) at a ratio of 1:1 by age, sex, curve type, major curve degree, and apical vertebral translation (AVT). Clinical assessment and radiological parameters were measured and compared.

RESULTS

Demographic characteristics, preoperative main curve, and AVT were comparable between groups. The correction ability of the main curve, AVT, and apex vertebral rotation were better in group A at index surgery ( P < .05). The increase in T1-S1 and T1-T12 height was large in group A at index surgery ( P = .011, P = .074). The annual increase in spinal height was slower in group A, but without significant difference. The surgical time and estimated blood loss were comparable. Six complications occurred in group A, and 10 occurred in group B.

CONCLUSION

In this preliminary study, ACPS seems to provide better correction of apex deformity, while attaining the comparable spinal height at 2-year follow-up. Larger cases and longer follow-up are needed to achieve reproducible and optimal results.

Concave and convex growth do not differ over tethered vertebral segments, even with open tri-radiate cartilage

PURPOSE

To assess the following hypotheses related to vertebral body tethering (VBT): 1. VBT is associated with asymmetric (concave > convex) increases in height over the instrumented vertebra. 2. The instrumented Cobb angle improves following VBT surgery with growth.

METHODS

This is a retrospective case series of pediatric patients from a multicenter scoliosis registry treated with VBT between 2013 to 2021.

INCLUSION CRITERIA

patients with standing radiographs at < 4 months and ≥ 2 years after surgery. Distances between the superior endplate of the UIV and the inferior endplate of the LIV were measured at the concave corner, mid-point, and convex corner of the endplates. The UIV-LIV angle was recorded. Subgroup analyses included comparing different Risser scores and tri-radiate cartilage (TRC) closed versus open using student t-tests.

RESULTS

83 patients met inclusion criteria (92% female; age at time of surgery 12.5 ± 1.4 years) with mean follow-up time of 3.8 ± 1.4 years. Risser scores at surgery were: 0 (n = 33), 1 (n = 12), 2 (n = 10), 3 (n = 11), 4 (n = 12), and 5 (n = 5). Of the 33 Risser 0 patients, 17 had an open TRC, 16 had a closed TRC. The UIV-LIV distance at concave, middle, and convex points significantly increased from immediate post-op to final-follow-up for Risser 0 patients, but not for Risser 1-5 patients. Increases in UIV-LIV distance were not significantly different between concave, middle, and convex points for all groups. There was no significant improvement or worsening in UIV-LIV angle for any group.

CONCLUSION

At a mean of 3.8 years following VBT, 33 Risser 0 patients demonstrated significant growth in the instrumented segment, though there was no difference between concave or convex growth, even for patients with open TRC.

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.

Implant-Related Complications Do Not Interfere with Corrections with the Shilla Technique in Early Onset Scoliosis: Preliminary Results

Growth-preservation techniques are utilized in early onset scoliosis (EOS) cases requiring surgical intervention. The Shilla technique corrects the deformity by reducing additional surgeries with its growth-guidance effect. As with other techniques, various problems can be encountered following the administration of the Shilla technique. The aim of this study was to examine the effect of complications encountered with the Shilla treatment on correction and growth. Sixteen patients with a follow-up period of at least one year after receiving Shilla growth guidance for EOS were included in this retrospective study. No complications occurred, and no unplanned surgery was required in 50% of the cases. Of the remaining eight patients with postoperative implant-related complications (50%), six (37.5%) required unplanned surgery; this consequently caused implant failure in the proximal region in five cases (31.25%) and deep tissue infection around the implant in one case (6.25%). Deformity correction, spine length, and quality-of-life scores significantly improved in EOS through Shilla growth guidance. In terms of spinal growth and deformity correction, there were no significant differences between patients with implant-related problems and individuals without occurrences. Although implant-related problems were detected in our dataset and corresponding unexpected surgeries were necessary, these complications had no significant unfavorable influence on correction and spine growth.

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.

Thoracic insufficiency syndrome: Approaches to assessment and management

Thoracic insufficiency syndrome (TIS) was described in 2003 as the inability of the thorax to support normal respiration or lung growth. TIS includes a broad and disparate group of typically degenerative thoracospinal conditions. Although TIS arises due to a heterogeneous group of disorders and thus its incidence is not well quantified, general approaches to management and treatment exist. Evolving imaging techniques and measurements of health-related quality of life augment tests of pulmonary function to quantify disease burden, longitudinally and pre- and post-intervention. Intervention is primarily via growth-sparing surgery, for which several device options exist, to preserve vertical growth prior to a definitive spinal fusion at skeletal maturity.

The preliminary outcomes of vertebral body tethering in treating adolescent idiopathic scoliosis: a systematic review

PURPOSE

VBT is a novel alternative to spinal fusion surgery to treat skeletally immature AIS and was approved to correct idiopathic scoliosis in August 2019 by US Federal Drug Administration (FDA). To systemically review the preliminary outcomes of vertebral body tethering (VBT) in treating adolescent idiopathic scoliosis.

METHODS

The electronic databases PubMed, EMBASE, and Web of Science were queried up to January 2022 for articles regarding VBT. Basic characteristics of patients, changes of radiographic parameters in coronal and sagittal planes, and clinical outcomes of surgical treatment of VBT including complication and revision rates were summarized.

RESULTS

Twenty five studies met the inclusion criteria. Most studies (23/25) included patients with only skeletal immaturity. The average % correction of the main/tethered curve at final follow-up, and % correction of thoracic kyphosis at final follow-up were reported to be 15.6-106.5% and - 31.8 to 20.0%, respectively. The most common complications for VBT were tether breakage (n = 145;21.3%), pulmonary complications (n = 49; 6.9%), and overcorrection (n = 30; 4.2%). The revision rate was 13.1%.

CONCLUSION

VBT could effectively and safely correct spinal deformity in skeletally immature patients with AIS and preserve the motion and growth of the spine. However, VBT has a relatively high complication and revision rates. Therefore, surgeons should cautiously consider VBT for treating AIS. Future research efforts are needed to lower the complication and revision rates. Whatever, VBT is still in its infancy and may have a promising future as a non-fusion solution for AIS.

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.

Early-onset scoliosis: a narrative review

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

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

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

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

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

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

A Modified Self-Growing Rod Technique for Treatment of Early-Onset Scoliosis

Surgical treatment of early-onset scoliosis (EOS) remains challenging as no definitive surgical technique has emerged as the single best option in this varied patient population1-3. Although the available surgical techniques may differ substantially, they all share the same goals of achieving and maintaining deformity correction, allowing physiological spinal growth, and reducing the number of operations and complications. Herein, we present a modified self-growing rod technique that represents a valid alternative to the existing surgical procedures for EOS.

DESCRIPTION

The patient is positioned prone on a radiolucent table, and the spine is prepared and draped in a standard fashion. A posterior midline skin incision is made from the upper to the lower instrumented level. Subperiosteal exposure of the spine is carried out, ensuring that capsules of the facet joints are spared. Pedicle screws are inserted bilaterally at the cranial and caudal ends of the instrumentation. Fixation with pedicle screws of at least 3 levels at the top and bottom end is usually advised; in nonambulatory patients with pelvic obliquity, caudal fixation can be extended to the pelvis with bilateral iliac screws. Sublaminar wires are positioned bilaterally at every level between the cranial and caudal ends of the instrumentation and are passed as medially as possible to avoid damage to the facet joints. Four 5-mm cobalt-chromium rods are cut, contoured, and inserted at each end of the construct. Ipsilateral rods are secured with use of sublaminar wires, making sure that they overlap over a sufficient length to allow for the remaining spinal growth. Correction of the deformity is achieved with use of a combination of cantilever maneuvers and apical translation by progressive and sequential tightening of the sublaminar wires. The wound is closed in layers over a subfascial drain. The patient is allowed free mobilization after surgery. No postoperative brace is required.

ALTERNATIVES

Nonoperative alternative treatment for EOS includes serial cast immobilization and bracing4. Alternative surgical treatments include traditional growing rods5, magnetically controlled growing rods6, the vertical expandable prosthetic titanium rib-expansion technique7, and the Shilla technique8. The use of compression-based systems (i.e., staples or tether)9 or early limited fusion has also been reported by other authors.

RATIONALE

The main advantage of our technique is that it relies on physiological spinal growth and does not require surgery or external devices for rod lengthening, which is particularly beneficial in frail patients with a neuromuscular disease in whom repeated surgery is not advised. Segmental fixation by sublaminar wires allows good control of the deformity apex during growth. Concerns regarding early fusion of the spine have not been confirmed in our mid-term follow-up study10.

EXPECTED OUTCOMES

This technique allows correction of the deformity and continuous spinal growth in the years following surgery. At 6.0 years postoperatively, the average main curve correction was reported to be 61% and the average pelvic obliquity correction was 69%. The spine was reported to lengthen an average of 40.9 mm (range, 14.0 to 84.0 mm) immediately postoperatively, and the T1-S1 segment was reported to continue growing at 10.5 mm/year (range, 3.6 to 16.5 mm/year) thereafter10. The most common complication is rod breakage at the thoracolumbar junction, which seems to be more common in patients with idiopathic or cerebral palsy EOS and during the pubertal growth spurt10.

IMPORTANT TIPS

Subperiosteal exposure of the spine should be carried out, making sure to preserve facet joints in the unfused area of the spine.Achieve segmental fixation with use of sublaminar wires at every level and pedicle screws at the top and bottom ends of the instrumentation.If pelvic imbalance is present and the patient is nonambulatory, pelvic fixation with iliac screws is advised.First round correction of the deformity is achieved with a cantilever technique; correction fine-tuning can be performed by tightening sublaminar wires.Consider utilizing thicker rods in cases of idiopathic or cerebral palsy EOS.

ACRONYMS AND ABBREVIATIONS

EOS = early-onset scoliosisAP = anteroposteriorEV = end vertebraSSEP = somatosensory evoked potentialsMEP = motor evoked potentialsPJK = proximal junctional kyphosisSMA = spinal muscular atrophyCP = cerebral palsyPACU = post-anesthesia care unit.

A comparison of the inflammatory host response to particulate debris adjacent to unlocked and locked screws of a growth guidance system for early onset scoliosis

PURPOSE

The SHILLA™ Growth Guidance system is a stainless-steel rod and screw system used for Early Onset Scoliosis which incorporates a unique flanged set screw designed to capture the rod, while allowing it to slide as the patient grows. Concomitant with this design is the potential for generation of wear debris and for an inflammatory host response. We hypothesized that the magnitude of the host response adjacent to the unlocked screws and rods would be greater than the host response to the locked rod/screws.

METHODS

Seven tissue samples adjacent to locked (3) and unlocked screws (4) from three SHILLA patients (mean implantation time of 19 post-operative months) with infantile idiopathic scoliosis were obtained as part of an explant analysis protocol during a PMDA-approved clinical trial in Japan. Gross appearance, high-resolution radiographs, and histology were assessed. ISO Standard 10993 Part 6 was used to assess the host response.

RESULTS

All three locked screw had no metallosis. In contrast, metallosis for unlocked screw tissue samples were rated as "ubiquitous" (2/4), "focal" (1/4), or "absent" (1/4). Microscopic metallic debris was found intracellularly and within interstices of fibrous connective tissues more frequently adjacent to unlocked screws compared to locked screws. Cell type and population scoring consistently showed a modestly larger inflammatory response (macrophages) in the unlocked tissue samples.

CONCLUSIONS

The peri-prosthetic tissue response to the unlocked rods/screws had a higher reactivity grade (slight reaction, Δ = 4.0) per ISO 10993 Part 6 compared to the locked screws in three patients with the SHILLA™ Growth Guidance scoliosis system.

Anterior vertebral body tethering for idiopathic scoliosis in growing children: A systematic review

BACKGROUND

The management of idiopathic scoliosis (IS) in skeletally immature patients should aim at three-dimensional deformity correction, without compromising spinal and chest growth. In 2019, the US Food and Drug Administration approved the first instrumentation system for anterior vertebral body tethering (AVBT), under a Humanitarian Device Exception, for skeletally immature patients with curves having a Cobb angle between 35° and 65°.

AIM

To summarize current evidence about the efficacy and safety of AVBT in the management of IS in skeletally immature patients.

METHODS

From January 2014 to January 2021, Ovid Medline, Embase, Cochrane Library, Scopus, Web of Science, Google Scholar and PubMed were searched to identify relevant studies. The methodological quality of the studies was evaluated and relevant data were extracted.

RESULTS

Seven clinical trials recruiting 163 patients were included in the present review. Five studies out of seven were classified as high quality, whereas the remaining two studies were classified as moderate quality. A total of 151 of 163 AVBT procedures were performed in the thoracic spine, and the remaining 12 tethering in the lumbar spine. Only 117 of 163 (71.8%) patients had a nonprogressive curve at skeletal maturity. Twenty-three of 163 (14.11%) patients required unplanned revision surgery within the follow-up period. Conversion to posterior spinal fusion (PSF) was performed in 18 of 163 (11%) patients.

CONCLUSION

AVBT is a promising growth-friendly technique for treatment of IS in growing patients. However, it has moderate success and perioperative complications, revision and conversion to PSF.

Clinical Results of Corrective Cast and Brace Treatment for Early-onset Scoliosis: The Effectiveness of Long-term Cast Treatment That Extends into Children's Schooldays

BACKGROUND

Cast and brace treatment is a conservative treatment for early-onset scoliosis (EOS). We analyzed the clinical results of this treatment when extended into patients' schooldays.

METHODS

Twenty-two children with EOS underwent alternatively repetitive cast and brace treatment (ARCBT). Cast was applied under general anesthesia and remained for some weeks, and the brace was continuously worn, which was repeatedly applied when scoliosis progressed. The change in the major curve angle, requirement for surgical intervention, and complications of ARCBT were analyzed.

RESULTS

Six patients had idiopathic scoliosis (IS), 9 had syndromic scoliosis (SS), and 7 had neuromuscular scoliosis. Cast treatment started at 4.9±2.1 years of age, and the patients were followed up for 8.3 years. The average total number of cast applications was 5.5 per patient. The mean major scoliosis angle was 45.4±12.5 degrees at the first visit; this was corrected to 26.5±8.7 degrees at the first cast application and progressed to 75.4±22.1 degrees at the final visit. Nine patients whose scoliosis progressed finally underwent surgery. The mean age at surgery was 11.0 years (range, 8.8 to 13.1 y), and the mean period from first cast application to surgery was 6.1 years (range, 5.0 to 8.9 y). Four patients' IS rapidly progressed after 9 years of age, and all of them underwent final fusion surgery with a correction rate of 56.9%. Among patients with SS, 1 final fusion, and 2 growth-friendly surgeries were performed at a mean age of 9.2 years; the correction rate was 21.5%. Among patients with neuromuscular scoliosis, 2 final fusion surgeries were performed at a mean age of 11.3 years; the correction rate was 30.7%. The cast-related complication rate was 5.0%, and most complications were skin problems.

CONCLUSIONS

Long-term ARCBT extended into schooldays might be effective for IS. This should be considered as a time-saving treatment option for EOS.

LEVEL OF EVIDENCE

Level IV-case series.

Prospective Follow-up Report on Anterior Vertebral Body Tethering for Idiopathic Scoliosis: Interim Results from an FDA IDE Study

BACKGROUND

Anterior vertebral body tethering (aVBT) has emerged as a novel treatment option for patients with idiopathic scoliosis. We present the results from the first U.S. Food and Drug Administration (FDA) Investigational Device Exemption (IDE) study on aVBT.

METHODS

In this prospective review of a retrospective data set, eligible patients underwent aVBT at a single center from August 2011 to July 2015. Inclusion criteria included skeletally immature patients with Lenke type-1A or 1B curves between 30° and 65°. Clinical and radiographic parameters were collected, with the latter measured by an independent reviewer.

RESULTS

Fifty-seven patients (49 girls and 8 boys), with a mean age (and standard deviation) of 12.4 ± 1.3 years (range, 10.1 to 15.0 years), were enrolled in the study. The patients had a mean of 7.5 ± 0.6 levels tethered, the mean operative time was 223 ± 79 minutes, and the mean estimated blood loss was 106 ± 86 mL. The patients were followed for an average of 55.2 ± 12.5 months and had a mean Risser grade of 4.2 ± 0.9 at the time of the latest follow-up. The main thoracic Cobb angle was a mean of 40.4° ± 6.8° preoperatively and was corrected to 18.7° ± 13.4° at the most recent follow-up. In the sagittal plane, T5-T12 kyphosis measured 15.5° ± 10.0° preoperatively, 17.0° ± 10.1° postoperatively, and 19.6° ± 12.7° at the most recent follow-up. Eighty percent of patients had curves of <30° at the most recent follow-up. The most recent Scoliosis Research Society (SRS) scores averaged 4.5 ± 0.4, and scores on the self-image questionnaire averaged 4.4 ± 0.7. No major neurologic or pulmonary complications occurred. Seven (12.3%) of 57 patients had a revision: 5 were done for overcorrection and 2, for adding-on.

CONCLUSIONS

Anterior VBT is a promising technique that has emerged as a treatment option for patients with immature idiopathic scoliosis. We present the results from the first FDA-approved IDE study on aVBT, which formed the basis for the eventual Humanitarian Device Exemption approval. The findings affirm the safety and efficacy of this technique and suggest opportunities for improvement, particularly with respect to reoperation rates.

LEVEL OF EVIDENCE

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

Complications in growth-friendly spinal surgeries for early-onset scoliosis: Literature review

BACKGROUND

The treatments for early-onset scoliosis (EOS), defined as curvature of the spine with onset before 10 years of age, continue to pose a great challenge for pediatric orthopedics. The treatment goals for EOS include minimizing spinal deformity while maximizing thoracic volume and pulmonary function. Different surgical techniques have different advantages and drawbacks; however, the two major concerns in the management of EOS are repeated surgeries and complications.

AIM

To review the current literature to assess the safety of EOS surgical treatment in terms of the rate of complications and unplanned surgeries.

METHODS

In January 2021 two independent reviewers systematically searched three electronic medical databases (PubMed, the Cochrane Library, and Embase) for relevant articles. Every step of the review was done according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Due to the heterogeneity of articles and topics after data analysis, a descriptive (synthetic) analysis was performed.

RESULTS

A total of 2136 articles were found. Forty articles were included in this systematic review, after applying our inclusion and exclusion criteria. EOS surgery has a varying but high rate of complications. The most frequent complications were categorized as implant (54%), general (17%), wound (15%) and alignment (12%). The rate of complications might have been even higher than reported, as some authors do not report all types of complications. About 54% of patients required unplanned surgeries due to complications, which comprised 15% of all surgeries.

CONCLUSION

The literature concerning the definitions, collection, and interpretation of data regarding EOS surgery complications is often difficult to interpret. This creates problems in the comparison, analysis, and improvement of spine surgery practice. Additionally, this observation indicates that data on the incidence of complications can be underestimated, and should be interpreted with caution. Awareness of the high rate of complications of EOS surgery is crucial, and an optimal strategy for prevention should become a priority.

[Nonfusion procedures in pediatric scoliosis]

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

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

PURPOSE

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

METHODS

Systematic literature review.

RESULTS

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

CONCLUSION

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

One-way self-expanding rod for early-onset scoliosis: early results of a clinical trial of 20 patients

PURPOSE

Progressive early-onset scoliosis raises major challenges for surgeons, as growth must be preserved. With traditional growing rods, the need for repeated surgery is associated with numerous complications, high costs, and heavy psychosocial burden on the patient and family. We assessed the safety and efficacy of a new one-way self-expanding rod (OWSER).

METHODS

This prospective single-centre phase 2 study included two groups of children with progressive EOS treated by the OWSER in 2016-2017: Ten received a unilateral construct to treat progressive non-neuromuscular curves and 10 others a bilateral construct for neuromuscular scoliosis. Clinical and radiological data were assessed at surgery and 3, 6, 12, 18 months later. The primary endpoint was success defined as the absence of repeated surgery at 12 months.

RESULTS

In the non-neuromuscular group, rod expansion occurred in 5 of 10 patients [95% CI 19-81]; in the five other patients, rotational conflict inside the domino prevented rod expansion, four of them required surgery within the first 12 months. Rod expansion occurred spontaneously and during monthly traction sessions in all 10 neuromuscular patients [95% CI 69-100], without mechanical or device-related complications. Residual pelvic obliquity was improved by -3° [- 6.0 to 9.5] at 18 months. Lung function improved in the non-neuromuscular group.

CONCLUSION

In neuromuscular diseases, the OWSER bilateral construct seems to be safe and less aggressive. Used as unilateral construct in non-neuromuscular group, it was less effective. Accordingly, we recommend the bilateral construct for all aetiologies. That device could avoid further surgery and reduce the rate of complications after long follow-up.

Shilla Growth Guidance Compared With Magnetically Controlled Growing Rods in the Treatment of Neuromuscular and Syndromic Early-onset Scoliosis

STUDY DESIGN

Retrospective review of consecutive series of patients treated at two institutions.

OBJECTIVE

The aim of this study was to compare the health-related quality of life (HRQoL) and surgical outcomes of Shilla growth guidance and magnetically controlled growing rod (MCGR) treatment in patients with syndromic and neuromuscular early-onset scoliosis (EOS).

SUMMARY OF BACKGROUND DATA

Knowledge of the outcomes of Shilla instrumentation is limited.

METHODS

We identified 13 children treated with Shilla and 18 children treated with MCGR with syndromic or neuromuscular EOS (major curve ≥45 degree) before the age of 10 years with minimum 2-year follow-up. Outcome parameters included clinical data, radiographic as well as HRQoL outcomes (EOSQ-24 questionnaire).

RESULTS

Mean preoperative major curves were 64 degree (range, 45-108 degree) in the Shilla group and 58 degree (range, 45-85 degree) in the MCGR group (P = 0.151). At final follow-up, mean major curves were 31 degree (range, 9.4-54 degree ) and 30 degree (range, 16-53 degree), respectively (P = 0.392). The mean major curve correction was 45% in the Shilla group and 48% in the MCGR group during the follow-up (P = 0.383). Spinal (T1-S1) and T1-T12 growth were significantly better (P = 0.006 and 0.042) in the MCGR than in the Shilla group during the distraction period. At final follow-up, 11 (85%) children in the Shilla group and 17 (94%) in the MCGR group had achieved T1-T12 length of ≥18 cm (P = 0.202). There were significantly more surgical procedures in the MCGR group (mean 2.6 vs. 1.4, P = 0.034) with no difference in the number of complications (P = 0.768). EOSQ24 domains were similar at final follow-up.

CONCLUSION

Shilla growth guidance provided similar correction of spinal deformity, equal number of complications, but with significantly less surgical procedures in patients treated for EOS when compared with MCGR instrumentation. MCGR provided with slightly better spinal growth during the distraction period. There were no significant differences between the quality of life assessments.

LEVEL OF EVIDENCE

3.

Treatment of early-onset scoliosis: techniques, indications, and complications

The treatments for early-onset scoliosis (EOS) remain great challenges for spine surgeons. This study aimed to comprehensively review the treatments for EOS, especially the advancements made in the last decade. Current studies on EOS were retrieved through a search on PubMed, UpToDate, the Web of Science Core Collection and Scopus were reviewed. The most pertinent information related to the current treatments for EOS was collected. The foci of treatments for EOS have included creating a well-developed thoracic cavity, improving lung volume, and improving pulmonary function. Conservative treatments include bracing, casting, halo-gravity traction, and physiotherapy. Serial casting is the most effective conservative treatment for EOS. Surgical treatments mainly include growth-friendly techniques, which are generally classified into three types according to the amount of correction force applied: distraction-based, compression-based, and growth-guided. The distraction-based systems include traditional or conventional growing rods, magnetically controlled growing rods, and vertical expandable prosthesis titanium ribs. The compression-based systems include vertebral body stapling and tethering. The growth-guided systems include the Shilla system and modern Luque trolley. In addition, some newer techniques have emerged in recent years, such as posterior dynamic deformity correction (ApiFix). For EOS patients presenting with sharp deformities in a long, congenital spinal deformity, a hybrid technique, one-stage posterior osteotomy with short segmental fusion and dual growing rods, may be a good choice. Hemivertebra resection is the gold standard for congenital scoliosis caused by single hemivertebra. Although the patient's growth potential is preserved in growth-friendly surgeries, a high complication rate should be expected, as well as a prolonged treatment duration and additional costs. Knowledge about EOS and its treatment options is rapidly expanding. Conservative treatments have specific limitations. For curves requiring a surgical intervention, surgical techniques may vary depending on the patients' characteristics, the surgeon's experience, and the actual state of the country.

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.

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

BACKGROUND

Growth-friendly treatment of early-onset scoliosis (EOS) has changed with the development and evolution of multiple devices. This study was designed to characterize changes in the use of growth-friendly implants for EOS from 2007 to 2017.

METHODS

We queried the Pediatric Spine Study Group database for patients who underwent index surgery with growth-friendly implants from July 2007 to June 2017. In 1298 patients, we assessed causes of EOS; preoperative curve magnitude; age at first surgery; patient sex; construct type; lengthening interval; incidence of "final" fusion for definitive treatment; and age at definitive treatment. α=0.05.

RESULTS

From 2007 to 2017, the annual proportion of patients with idiopathic EOS increased from 12% to 33% (R=0.58, P=0.006). Neuromuscular EOS was the most common type at all time points (range, 33% to 44%). By year, mean preoperative curve magnitude ranged from 67 to 77 degrees, with no significant temporal changes. Mean (±SD) age at first surgery increased from 6.1±2.9 years in 2007 to 7.8±2.5 years in 2017 (R=0.78, P<0.001). As a proportion of new implants, magnetically controlled growing rods increased from <5% during the first 2 years to 83% in the last 2 years of the study. Vertically expandable prosthetic titanium ribs decreased from a peak of 48% to 6%; growth-guidance devices decreased from 10% to 3%. No change was seen in mean surgical lengthening intervals (range, 6 to 9 mo) for the 614 patients with recorded lengthenings. Final fusion was performed in 88% of patients who had undergone definitive treatment, occurring at a mean age of 13.4±2.4 years.

CONCLUSIONS

From 2007 to 2017, neuromuscular EOS was the most common diagnosis for patients treated with growth-friendly implants. Patient age at first surgery and the use of magnetically controlled growing rods increased during this time. Preoperative curve magnitude, traditional growing rod lengthening intervals, and rates of final fusion did not change.

LEVEL OF EVIDENCE

Level II.

Current status of the magnetically controlled growing rod in treatment of early-onset scoliosis: What we know after a decade of experience

The magnetically controlled growing rod (MCGR) has had approximately 10 years of clinical experience worldwide. Clinical effectiveness to control early-onset scoliosis is consistent even at final surgery. MCGRs have significantly lower relative percentage of infection or wound complications as compared to traditional growing rods. Most common complications include foundation failure and failure of distraction. Contouring of the rod especially at the proximal segment while accommodating for the straight actuator remains a difficult task and its failure may lead to proximal junctional kyphosis. Unique complications of MCGR include clunking, temporary diminishing distraction gains, and metallosis. Temporary reductions in distraction gains are observed as the MCGR lengthens but return to normal baseline distraction gains after rod exchange. Lack of standardization for rod configuration, distraction strategies and decisions of whether to keep the rods in situ, remove without fusion surgery or to perform spinal fusion at skeletal maturity will require further study.

Anterior Vertebral Body Tethering for Adolescent Scoliosis with Growth Remaining: A Retrospective Review of 2 to 5-Year Postoperative Results

BACKGROUND

Anterior vertebral body tethering (VBT) is an early treatment option for progressive scoliosis in pediatric patients, allowing for continued deformity correction during normal growth. We report postoperative radiographic and clinical outcomes for patients treated with VBT.

METHODS

This clinical and radiographic retrospective review of 31 consecutive patients included an analysis of preoperative, perioperative, and postoperative details, including the Lenke classification; Cobb angle measurements of the proximal thoracic, main thoracic, and lumbar curves; the sagittal profile; and skeletal maturity. Successful outcomes were defined by a residual curve of ≤30° in skeletally mature patients who did not undergo a posterior spinal fusion (PSF).

RESULTS

Of the 31 patients treated, 29 met the inclusion criteria, and 2 were lost to follow-up. The mean patient age (and standard deviation) at the time of the surgical procedure was 12.7 ± 1.5 years (range, 10.2 to 16.7 years), with most patients classified as Risser grade 0 or 1 (52%) and Sanders stage 3 (32%). A mean of 7.2 ± 1.4 vertebral levels were instrumented, with a minimum preoperative Cobb angle of 42°. At the latest follow-up, 27 patients had reached skeletal maturity (Sanders stage ≥7) and 20 patients exhibited a curve magnitude ≤30°, for a success rate of 74%. A suspected broken tether occurred at ≥1 level in 14 patients (48%). Two patients underwent PSF and 4 had tether revision. The overall revision rate was 21% (6 of 29).

CONCLUSIONS

This study shows the success and revision rates as well as the impact of a suspected broken tether on the procedural success of VBT. Despite our patient population being slightly more mature at the time of the surgical procedure compared with previous studies, we had a higher success rate and a lower revision rate. A PSF was avoided in 93% of patients, indicating that VBT may be a reliable treatment option for adolescent scoliosis in skeletally immature individuals.

LEVEL OF EVIDENCE

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

Growth guidance constructs with apical fusion and sliding pedicle screws (SHILLA) results in approximately 1/3rd of normal T1-S1 growth

STUDY DESIGN

Retrospective, multicenter.

OBJECTIVE

To investigate clinical outcomes in particular T1-S1 growth in patients with SHILLA instrumentation independent of inventor's reports. Guided growth with apical fusion and sliding pedicle screws (GGC/SHILLA) is an alternative to distraction-based growing rods for the treatment of EOS. A recent report of patients treated with GGC primarily at the center where the procedure was invented reported surprisingly good spinal growth similar to normal growth.

METHODS

Retrospective review of EOS patients treated with GGC between 2007 and 2013 was performed from a multicenter database prior to final fusion. Inclusion criteria were < 10 years at index surgery and minimum 2-year follow-up. Patients with GGC performed at the inventor's institution or prior spinal instrumentation were excluded. Predicted normal T1-S1 change during the growth period was calculated for each patient based on Dimeglio's growth rates.

RESULTS

20 patients (mean age at surgery: 5.7 years) with the following diagnoses met inclusion criteria: syndromic (N = 9), neuromuscular (N = 5), idiopathic (N = 3) and congenital (N = 3). Preoperative mean Cobb was 77° (range 33°-111°). Mean increase in T1-S1 length from preoperative to postoperative was 51.5 mm, and change from postoperative to final follow-up was 21.8 mm (4.2 mm/year) which was 36% of predicted growth. 15/20 (75%) patients underwent 21 revision surgeries most commonly for implant complications (N = 26) and 8/20 (40%) underwent definitive fusion at a mean of 5.1 ± 1.2 years after guided growth surgery.

CONCLUSION

This study constitutes the largest case series of patients with EOS treated with GGC outside of the inventor's institution. The change in T1-S1 observed through the follow-up period in EOS patients treated with GGC was approximately 1/3rd of predicted normal growth, and less than 1/3rd of growth reported in previous reports. Similar curve correction and complication rates but less T1-S1 growth during the growth period were found compared to prior GGC (SHILLA) series.

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.

Curve Modulation and Apex Migration Using Shilla Growth Guidance Rods for Early-onset Scoliosis at 5-Year Follow-up

BACKGROUND

The Shilla procedure was designed to correct and control early-onset spinal deformity while harnessing a child's remaining spinal growth. It allows for controlled axial skeletal growth within the construct, avoiding the need for frequent surgeries to lengthen implants. We hypothesized that curve characteristics evolve over time after initial apex fusion and placement of the Shilla implants. The purpose of this study was to identify trends in curve evolution after Shilla implantation and understand how these changes influence ultimate outcome.

METHODS

A single-center, retrospective review of all patients with Shilla implants in place for ≥5 years yielded 21 patients. Charts and radiographs were reviewed to compare coronal curve characteristics preoperatively, postoperatively, and at last follow-up to note changes in the apex of the primary curve. Also noted were the development of adjacent compensatory curves, the overall vertical spinal growth, and the need for definitive spinal fusion once skeletal maturity was reached.

RESULTS

Of the 21 patients, the curve apex migrated caudally in 12 patients (57%) and cephalad in 1 patient (5%), with a mean migration of 2.7 vertebral levels. Two patients (10%) developed new, significant compensatory curves (1 caudal and 1 cephalad). All patients demonstrated spinal growth in T1-S1 length following index surgery (mean, 45 mm). At skeletal maturity, 10 patients underwent definitive posterior spinal fusion and instrumentation, and 3 underwent implant removal alone.

CONCLUSIONS

This study constitutes the longest follow-up of Shilla patients evaluating curve and implant behavior. Results of this review suggest that the apex of the fused primary curve shifts in approximately 62% of patients, with nearly all of these (92%) involving a distal migration. Compensatory curves did develop after Shilla placement as well. Overall, these findings represent adding-on distal to the apex after Shilla instrumentation rather than a crankshaft phenomenon about the apex. A better understanding of spinal growth mechanics and outcomes after Shilla placement may improve our ability to appropriately select patients and instrumentation levels.

LEVEL OF EVIDENCE

Level III.

Biomechanical Analysis of a Growing Rod with Sliding Pedicle Screw System for Early-Onset Scoliosis

Early-onset scoliosis (EOS) remains a challenging condition for which current nonfusion surgeries require iterative lengthening surgeries. A growing rod with sliding pedicle screw system (GRSPSS) was developed to treat spinal deformities without repeated operative lengthening. This study was performed to evaluate whether GRSPSS had similar stability as a conventional pedicle screw system to maintain deformity correction. A serial-linkage robotic manipulator with a six-axis load cell positioned on the end-effector was utilized to evaluate the mechanical stability of the GRSPSS versus conventional fixed scoliosis instrumentation. Ten skeletally mature thoracic female Katahdin sheep spines (T4-L1) were subjected to 2.5 Nm of flexion-extension (FE), lateral bending (LB), and axial rotation (AR) in 2° increments for each state. The overall range of motion (ROM), apical segment ROM, and stiffness were calculated and reported. A two-tailed paired t-test was used to detect significant differences (p < 0.05) between the fixed group and GRSPSS fixation. There were no significant differences in overall range of motion (ROM), apical segment ROM, or stiffness for FE or LB between the GRSPSS group and fixed group. In AR, the GRSPSS group showed increased ROM compared to the fixed group for the overall spine (36.0° versus 19.2°, p < 0.01) and for the instrumented T8-T10 segments (7.0° versus 2.9°, p=0.02). Similarly, the fixed rod elastic zone (EZ) stiffness was significantly greater than the GRSPSS EZ stiffness (0.29 N/m versus 0.17 N/m, p < 0.001). The space around the rod allows for the increased AR observed with the GRSPSS fusion technique and is necessary for axial growth. The GRSPSS fusion model shows equivalent flexion and LB stability to current fusion models and represents a stable fusion technique and may allow for longitudinal growth during childhood.

In Patients with Early-Onset Scoliosis, Can Growing Rods Be Removed Without Further Instrumentation? An Evidenced-Based Review

Early-onset scoliosis (EOS) is defined by the presence of spinal deformity in children 10 years of age or younger. Left untreated, patients with EOS are at high risk for thoracic insufficiency and early demise. This article provides a critical review of a recent prospective cohort study of children with EOS: "Graduation Protocol After Growing-Rod Treatment: Removal of Implants without New Instrumentation Is Not a Realistic Approach," by Kocyigit and colleagues (J Bone Joint Surg Am. 2017;99(18):1554-1564). Treatment for EOS requires deformity correction while accommodating the growing spine. Dual growing rod implantation is a well-described technique that consists of the placement of two telescoping rods anchored to vertebrae proximal and distal to the apex of the curve. Multiple lengthening procedures are then performed as the child grows. Management of the endpoint of growing rod treatment remains controversial, with high complication rates associated with final fusion. As an alternative to final fusion or implant retention, Kocyigit and colleagues examined the removal of growing rods without spinal fusion and found that this procedure resulted in substantial worsening of the deformity in nine out of ten patients. This treatment group was terminated on ethical grounds. We believe this important result demonstrates that the removal of implants without fusion is an unacceptable treatment strategy that leads to poor outcomes.

Surgical growth guidance with non-fused anchoring segments in early-onset scoliosis

PURPOSE

Surgical treatment of early-onset scoliosis (EOS) requires a balance between maintained curve correction and the capacity for spinal and thoracic growth. Spinal fusion creates irreversible conditions that prevent the implementation of further treatment methods. Our hypothesis was that non-fused anchors in growth guidance show a comparable outcome as the technique described in the literature, which involves spondylodesis of the anchoring segments.

METHODS

This retrospective study analysed 148 surgeries in 22 EOS patients (11 female, 11 male) over a 15-year period. Patients underwent surgery with non-fused anchors and growth guidance techniques. Scoliosis, kyphosis, growth and anchoring segments were measured. For the latter, a new measuring technique was developed. Complications were recorded and classified.

RESULTS

The mean Cobb angle reduced from 73.5 ± 24.4° to 28.4 ± 16.2° (60.2 ± 22.9%, p < 0.001) at the last follow-up. Spinal growth T1-S1 and T1-T12 were 41.1 ± 23.3 mm and 24.9 ± 16.6 mm (p < 0.001), respectively. Growth at the cranial and caudal anchoring segment was 1.5 mm/segment/year and 1.9 mm/segment/year, respectively. A total of 63 complications were documented in 20 patients, with 40 requiring unplanned revision surgery. Definitive spondylodesis was performed in three patients.

CONCLUSION

Patients demonstrated a significant spinal growth including the anchoring segments. A comparable correction in Cobb angle and the type of complications was noted, although the rate of device-related complications was higher. No permanent impairment was reported. The rate of device-related complications is acceptable and outweighed by the significant degree of growth preservation and more flexible and individualised treatment strategy for patients with EOS. These slides can be retrieved under Electronic Supplementary Material.

Preliminary Study of a New Growing Rod System in Immature Swine Model

BACKGROUND

Growing rod techniques have been demonstrated to be a valuable treatment in early-onset scoliosis; however, repeated surgeries and general anesthesia cannot be avoided.

METHODS

This study included 12 immature swine that were randomly assigned to receive either a novel growing rod system (experimental group) or a traditional growing rod system (control group). Lengthening was undertaken at 4-week intervals, for a total observation period of 12 weeks. Radiography, computed tomography, and motion analysis of the spine were conducted to evaluate rod extension, growth and nonfusion of the spine, and fixation.

RESULTS

One swine (control group) was excluded from the analysis because of a deep wound infection at 1 week after the initial operation. No complications were observed in the remaining 11 swine. In the experimental group, the average lengthening operation lasted 12.1 ± 3.1 minutes, and average incision length was 1.1 ± 0.2 cm; both values were significantly less compared with the control group (P < 0.001). No significant between-group differences in mean trunk length, body mass, or thickness of cephalad-instrumented or caudad-instrumented vertebrae and intervertebral disks were present before the initial operation or at the final assessment (12 weeks after operation; P > 0.05). Spinal growth and motion of instrumented spinal segments were conserved.

CONCLUSIONS

The novel growing rod system is safe and effective in immature swine, preserving spine growth potential and involving less surgical trauma.

Comparison of Intended Lengthening of Magnetically Controlled Growing Rods: Ultrasound Versus X-Ray

BACKGROUND

In the treatment of early onset scoliosis (EOS), there has been a trend to use magnetically controlled growing rods (MCGR) in order to reduce the number of surgeries. To confirm the amount of lengthening, spine radiographs were required. Recently, ultrasound (US) has been added to monitor lengthening of MCGR to avoid radiation exposure. Our aim was to determine whether US is as accurate as plain radiography (x-ray) in determining the amount of length achieved at individual MCGR lengthening episodes.

METHODS

Retrospective study; inclusion criteria: EOS cases with dual MCGR with minimum 12 months follow-up. Intended lengthening IL (mm), lengthening on US (mm) and x-ray (mm) were documented from medical records for both right and left rods. Primary (no surgery before MCGR) and conversion (other types of instrumentation were replaced with MCGR) cases were reviewed separately. P-values determined with analysis of variance.

RESULTS

Sixteen cases with 100 lengthening episodes met the inclusion criteria. Eleven were primary MCGR cases with 67 episodes. Mean follow-up was 19±5 months. Significant differences were found between IL (3.4±1 mm), US (2.7±1.9 mm), and x-ray (4.1±2.2 mm) (P<0.001). The difference between IL and x-ray was minimal, but statistically significant (P=0.046). US showed statistically lower values than both IL (P=0.001) and x-ray (P<0.001). The mean ratio of x-ray/IL, US/IL, and US/x-ray were 1.1, 0.75, and 0.84, respectively. Five conversion cases had 33 episodes. Mean follow-up was 21±2 months. Significant differences were found between IL (3.4±0.8 mm), US (1.3±0.8 mm), and x-ray (1.7±0.9 mm) (P<0.001) but there was no significant difference between US and x-ray (P=0.283). IL was significantly higher than both US (P< 0.001) and x-ray (P<0.001). The mean ratio of x-ray/IL, US/IL, and US/x-ray were 0.64, 0.41, and 1.1, respectively.

CONCLUSIONS

US can provide confirmatory information of noninvasive lengthening of MCGR. However, US tended to underestimate the achieved length as measured by x-ray in primary cases. Conversion cases demonstrate better concordance between US and x-ray but in these cases less overall length was achieved at each lengthening episode.

LEVEL OF EVIDENCE

Level III.

Surgeon Experience Does Not Change Rate of Perioperative Surgical Complication in Rib-Based Distraction Surgery for Early-Onset Scoliosis

OBJECTIVE

To report on the surgical learning curve in treating early-onset scoliosis with rib-based distraction.

SUMMARY OF BACKGROUND DATA

The idea of a surgical learning curve proposes improved outcomes with experience. Early-onset scoliosis (EOS) is a challenging condition to treat and complication rates are high.

METHODS

All patients from a single experienced spine surgeon's practice who had undergone placement of rib-based distraction constructs between 2002 and 2013 were identified. A retrospective chart review was performed to determine patient characteristics at implantation and follow-up surgeries and complications. The primary outcome was complication rate per surgical encounter. Experience was analyzed both by number of surgical procedures and year in study period.

RESULTS

The surgeon began using rib-based distraction in 2002, and between 2002 and 2013, a total of 101 patients underwent 1,009 implantation or expansion surgeries involving rib-based distraction at a median age of 6 years at implantation (10 months-9.4 years). The median preoperative Cobb angle was 67° (8°-125°; IQR: 57°-76°) and follow-up was a median of 4.4 years (IQR 3.7-5.6 years). Overall, 65.3% of patients experienced complications, including 40 Grade I, 20 Grade II, 126 Grade IIA, and 3 Grade III. Univariate analysis identified a trend toward cumulative number of surgeries relating to a decreased complication rate, with every 50 surgeries decreasing the complication rate by 3% (p = .071). However, multivariate analysis found cumulative number of surgeries and complication rate to not be significantly related (p = .12). Surgeon experience as measured by study time (as both a continuous and categorical predictor) did not achieve statistical significance in either the univariate or multivariate models.

CONCLUSION

This is the largest single-surgeon series of EOS patients treated with rib-based distraction. Surgeon experience defined either as number of procedures or years of experience within the study period did not impact the rate of complications.

Early-Onset Scoliosis: Updated Treatment Techniques and Results

STUDY DESIGN

This is a review of the current literature on early-onset scoliosis (EOS) techniques and treatment written by the Growing Spine Committee of the Scoliosis Research Society.

OBJECTIVES

The Growing Spine Committee of the Scoliosis Research Society sought to update the information available on the definition and treatment of EOS, including new information about existing techniques.

SUMMARY OF BACKGROUND DATA

EOS represents a diverse, heterogeneous, and clinically challenging group of spinal disorders occurring in children under the age of 10. Our understanding of EOS has changed dramatically in the last 15 years, and management of EOS has changed even more rapidly in the last five years.

METHODS

The Growing Spine Committee of the Scoliosis Research Society has embarked upon a review of the most current literature on EOS techniques and treatment.

RESULTS

This white paper provides recent updates on current techniques, including a summary of new modalities, indications, contraindications, and clinical results.

CONCLUSIONS

Although treatment of EOS is still challenging and complicated, the evolution of options and knowledge presents hope for better understanding and management in the future.

LEVEL OF EVIDENCE

Level V.

Two for One: A Change in Hand Positioning During Low-Dose Spinal Stereoradiography Allows for Concurrent, Reliable Sanders Skeletal Maturity Staging

STUDY DESIGN

Prospective survey.

OBJECTIVES

To evaluate the reliability of low-dose stereoradiography compared to standard hand bone age films for assessing Sanders skeletal maturity stage in patients with idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

The Sanders skeletal maturity staging system is a valuable tool in the care of juvenile and adolescent spine scoliosis, but obtaining dedicated hand films adds additional time, radiation, and expense to the clinic visit. A change in patient hand positioning for routine full-length PA spine low-dose stereoradiography may offer a viable alternative.

METHODS

A survey consisting of 30 standard bone age hand films and 26 posteroanterior spine low-dose stereoradiography images (magnified view of hands only) was created in REDCap and distributed to two pediatric spine surgeons and two fellows. The graders were asked to classify the images according to the Sanders skeletal maturity classifications. Images were graded in two trials conducted one week apart. Inter- and intraobserver reliability was assessed using the mean linearly weighted kappa to provide an overall index of agreement.

RESULTS

In Trial 1, the interobserver reliability was similar for both the standard bone age films (κ = 0.82) and for the low-dose stereoradiography films (κ = 0.79) (p = .501). In Trial 2, reliability was similar between imagine modalities and slightly improved for both standard bone age films (κ = 0.85) and low-dose stereoradiography films (κ = 0.82) (p = .192). Intraobserver reliability was strong for both standard films (κ=0.89) and low-dose stereoradiography films (κ = 0.86) (p = .446).

CONCLUSION

A simple change in patient hand positioning for low-dose stereoradiography allows clinicians to simultaneously assess a patient's spinal deformity and skeletal maturity with excellent reliability. Given the frequency of scoliosis surveillance visits, this simple change could lead to significant savings of time, money, and radiation exposure for the growing child.

LEVEL OF EVIDENCE

Level III.

Novel use of telescoping growth rods in treatment of early onset scoliosis: An in vivo and in vitro study in a porcine model

INTRODUCTION

Treatment of early-onset scoliosis (EOS) can be difficult. Various forms of growing rods exist to correct deformity while delaying definitive spinal fusion. The disadvantage of traditional growing rods is need for repeated surgical lengthening procedures. Telescoping growth rods (TelGR) are a prototype new, guided growth technology with a rod mechanism that allows spontaneous longitudinal growth over time without manual lengthening. We hypothesized that the TelGR system will permit unrestricted growth with limited complications through 12 weeks in vivo, and that the range of motion (RoM) in each of three directions and stiffness of the TelGR system would not be significantly different than the rigid rod system in vitro.

MATERIALS AND METHODS

In vivo: Six immature pigs were surgically implanted with TelGR with cephalad fixation at T6-7 and caudal fixation at T14-L1. Radiographs of the involved vertebral segments were measured postoperatively and after 12 weeks. In vitro: A robotic testing system was utilized for flexibility tests in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) of eight immature porcine specimens (T3-T15). Testing was performed on both dual rigid rods and bilateral TelGR with instrumentation at T4-5 and T13-14.

RESULTS

In vivo: Over the 12-week period, the rod length of the TelGR increased an average of 65 mm. In vitro: TelGR demonstrated significantly increased motion in LB and AR RoM compared with rigid rods. No difference was noted in FE RoM.

DISCUSSION

The in vivo results in this study showed expected skeletal growth with spines instrumented with TelGR. In vitro findings of increased RoM in AR and LB suggest that the TelGR system may be less rigid than traditional growing rods. Treatment with TelGR might, if proven efficacious in the clinical setting, decrease the need for repeated surgical intervention compared with traditional growing rods. This study adds to the limited body of biomechanical evidence examining guided growth technology.