Growing rod techniques in early-onset scoliosis

How will early onset scoliosis surgery affect my child's future as a young adult? A follow-up study using patient-reported outcome measures

PURPOSE

Using patient-reported outcome measures (PROMs), this study was undertaken to determine how well patients with early onset scoliosis (EOS) fare in adulthood.

METHODS

Among eight healthcare centers, 272 patients (≥ 18 years) surgically managed for EOS (≥ 5 years) completed the Scoliosis Research Society (SRS)-22r, Functional Assessment of Chronic Illness Therapy-10 (FACIT-Dyspnea-10), and Short Form (SF)-12. Functional and demographic data were collected.

RESULTS

The response rate was 40% (108/272). EOS etiologies were congenital (45%), neuromuscular (20%), idiopathic (20%) syndromic (11%), and unknown (4%). All patients scored within normal limits on the FACIT-Dyspnea-10 pulmonary (no breathing aids, 78%; no oxygen, 92%). SF-12 physical health scores and most SRS-22r domains were significantly decreased (p < 0.05 and p < 0.001, respectively) compared with normative values. SF-12 and SRS-22r mental health scores (MHS) were lower than normative values (p < 0.05 and p < 0.02, respectively). Physical health PROMs varied between etiologies. Treatment varied by etiology. Patients with congenital EOS were half as likely to undergo definitive fusion. There was no difference between EOS etiologies in SF-12 MHS, with t scores being slightly lower than normative peers.

CONCLUSION

Good long-term physical and social function and patient-reported quality of life were noted in surgically managed patients. Patients with idiopathic EOS physically outperformed those with other etiologies in objective and PROM categories but had similar MHS PROMs. Compared to normative values, EOS patients demonstrated decreased long-term physical capacity, slightly lower MHS, and preserved cardiopulmonary function.

LEVEL OF EVIDENCE

Level IV Case Series.

Evaluation of crankshaft phenomenon after posterior fusion for early onset scoliosis using an inverse trigonometric function: a multicenter retrospective cohort study

PURPOSE

The crankshaft phenomenon (CSP) is a corrective loss after posterior surgery for early onset scoliosis (EOS). However, an accurate method for CSP evaluation has yet to be developed. In this study, we evaluated pedicle screw (PS) length and rotation angle using an inverse trigonometric function and investigated the prevalence of the CSP.

METHODS

Fifty patients from nine institutions (mean age 10.6 years, male/female ratio 4:46) who underwent early definitive fusion surgery at ≤ 11 years of age were included. The rotation angle was calculated as arctan (lateral/frontal PS length) using radiography. Measurements were taken at the apex and lower instrumented vertebra (LIV) immediate, 2-, and 5-year postoperatively. CSP was defined as a rotation angle progression ≥ 5°. We divided patients into CSP and non-CSP groups and measured the demographic parameters, Risser grade, state of the triradiate cartilage, major coronal Cobb angle, T1-T12 length, T1-S1 length, and presence of distal adding-on (DAO). We compared these variables between groups and investigated the correlation between the measured variables and vertebral rotation. Logistic regression analysis investigated factors associated with CSP.

RESULTS

The rotation angle progressed by 2.4 and 1.3° over 5 years for the apex and LIV, respectively. CSP occurred in 15 cases (30%), DAO in 11 cases (22%), and CSP and DAO overlapped in 4 cases (8%). In the CSP group, the T1-T12 length was low immediate postoperatively. The rotation angle was negatively correlated with preoperative height (r = - 0.33), T1-T12 length (r = - 0.35), and T1-S1 length (r = - 0.30). A lower preoperative T1-T12 length was associated with CSP (odds ratio: 0.996, p = 0.048).

CONCLUSIONS

CSP occurred in 30% of patients with EOS who underwent definitive fusion. The presence of CSP was associated with a lower preoperative T1-T12 length.

LEVEL OF EVIDENCE

Diagnosis, level IV.

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.

The Minimally Invasive Bipolar Fixation for Pediatric Spinal Deformities: A Narrative Review

Growing rod techniques are increasingly used for early-onset scoliosis in children. Unfortunately, they are associated with many complications, particularly neuromuscular scoliosis, favored by the poor general condition of these patients and the fragility of their osteoporotic bones. Furthermore, these interventions are often iterative and usually followed by vertebral fusion at the end of growth. This is a review of the literature on a recent fusionless technique, minimally invasive bipolar fixation, which is more stable than the traditional growing rod techniques and less aggressive than vertebral arthrodesis. It allows the avoidance of arthrodesis, owing to the solidity of the construct and the stability of the results, leading to progressive spinal stiffening that occurs over time. The results of this technique have been published with a long follow-up period and have confirmed that it can completely replace posterior vertebral arthrodesis, especially in the most complicated scoliosis. Because it preserves growth, this technique should be recommended for early-onset scoliosis before the age of 10 years. The use of a self-expanding rod can avoid the need for repeated surgery, thereby reducing the risk of complications and the overall cost of treatment.

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.

Long-term outcomes of ilio-sacral screws in minimally invasive bipolar fusionless technique for neuromuscular scoliosis: a retrospective study in 167 patients

INTRODUCTION

Pelvic fixation in patients with neuromuscular scoliosis is difficult, due to their fragile general condition and poor bone quality. Many techniques have been described, associated with high rates of mechanical complications. The objective of this work was to evaluate the mechanical complications and long-term radiological results of ilio-sacral screw pelvic fixation.

MATERIALS AND METHODS

167 consecutive patients with neuromuscular scoliosis who underwent minimally invasive bipolar fixation with ilio-sacral screw pelvic fixation were retrospectively reviewed. The instrumentation consisted in a bilateral sliding rods construct extended from T1 to the sacrum, anchored proximally by double-hook claws and distally by ilio-sacral screws through a minimally invasive approach. Mechanical complications and radiographic measurements (angle of the major coronal curve, pelvic obliquity, lumbar lordosis) were evaluated preoperatively, postoperatively, and at the last follow-up.

RESULTS

Mean operative age was 12 ± 3 years, and follow-up 6.4 years (3.0-10.4 years). Pelvic obliquity decreased from 20° preoperatively to 5° (77% correction) at last follow-up, Angle of the major coronal curve from 75° to 36° (52% correction), and lumbar lordosis from 28° to 38°. 16 mechanical complications in nine patients occurred: screw prominence (n = 1), connector failure (n = 4), screw malposition (n = 11). Unplanned surgery was required in seven cases, two were managed during rod lengthening, seven did not require treatment.

CONCLUSION

In this series of neuromuscular patients operated by ilio-sacral screws as pelvic fixation, the results were stable with a mean follow-up of more than 6 years and the complication rate was reduced comparatively to the literature.

LEVEL OF EVIDENCE: 4

Outcomes and Safety of Traditional Growing Rod Technique in the Treatment of Early-onset Dystrophic Scoliosis Secondary to Type 1 Neurofibromatosis With Intraspinal Rib Head Dislocation in Children

PURPOSE

The purpose of this study was to investigate the outcomes and safety of traditional growing rod (TGR) in the treatment of early-onset dystrophic scoliosis secondary to type 1 neurofibromatosis (NF1-EOS) with intraspinal rib head dislocation (IRH) in children.

METHODS

From September 2006 to June 2020, 21 patients with NF1-EOS were treated with TGR. The patients comprised 13 boys and 8 girls with a mean age of 7.1±1.5 years. Two patients had IRH-induced nerve injury [American Spinal Injury Association (ASIA) grade D]. No neurological symptoms were found in the other patients. The intraspinal rib proportion, apical vertebral rotation, apical vertebral translation, coronal main thoracic curve, trunk shift, thoracic kyphosis, lumbar lordosis, sagittal balance, and T1-S1 height were measured before and after TGR implantation and at the last follow-up. Complications were also evaluated.

RESULTS

The mean follow-up time was 3.4±2.0 years. An average of 3.1 times (range: 1 to 8 times) lengthening procedures were performed in each patient. The intraspinal rib proportion was significantly lower postoperatively than preoperatively (22±11% vs. 33±18%, respectively; P <0.001), and no significant correction loss was found at the last follow-up (24±12%, P= 0.364). Compared with the measurements before TGR implantation, the major coronal curve and T1-S1 height after TGR implantation and at the last follow-up were significantly different ( P <0.05). Significant correction of apical vertebral translation, thoracic kyphosis, lumbar lordosis, and sagittal balance were noted after TGR implantation, and no significant correction loss was found at the last follow-up ( P >0.05). Ten complications occurred in 7 patients. Two patients with nerve injury recovered after the operation. No neurological complications were found during the follow-up.

CONCLUSIONS

TGR is a safe and effective therapy for NF1-EOS with IRH where there was no direct compression of the spinal cord, which was confirmed by preoperative magnetic resonance imaging. Through this procedure, IRH could be partly removed from the spinal canal.

LEVEL OF EVIDENCE

Level III.

Comparative efficacy and complications of single and dual growing rods for early-onset scoliosis: an updated meta-analysis

PURPOSE

This updated meta-analysis aimed to compare single and dual growing rods, including both traditional growing rod and magnetically controlled growing rod (MCGR) used in the treatment of early-onset scoliosis (EOS) with regard to deformity correction, spinal growth, and complications.

METHODS

This meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using articles extracted from PubMed, EMBASE databases, and Cochrane Library databases. Only articles reporting the complications and the imaging parameters before and after growing rods in the patients diagnosed with EOS were included. We extracted and statistically analyzed the data deemed relevant for this study, and used the Newcastle-Ottawa Scale to assess the risk of bias in each study. Data synthesis and statistical analyses were performed using R software.

RESULTS

Fifteen eligible articles containing 409 participants (n = 185, single growing rods; n = 224, dual growing rods) were identified. The meta-analysis found no significant differences in the preoperative and postoperative major Cobb angle, T1-S1 distance, thoracic kyphosis, and coronal balance between single and dual rods groups. The final follow-up major Cobb angle (P = 0.01; standardized mean difference, - 0.42 [95% confidence interval (CI), - 0.74 to - 0.10]; I² = 23%) was significantly smaller in dual rods group than single-rod group. However, no significant differences in the correction rate of angle (major Cobb angle and kyphosis angle) and changes in the T1-S1 distance between the two groups were observed. Moreover, there were no significant differences in the metalwork failure, infection, or proximal junctional kyphosis between single and dual rods groups. However, total complications (P = 0.03; risk ratio (RR), 0.79 [95% CI, 0.63-0.98]; I² = 29%) and distraction failure in MCGR (P = 0.04; RR, 0.38 [95% CI, 0.14-0.98]; I² = 11%) were significantly lower in dual rods group than single-rod group.

CONCLUSION

This updated meta-analysis found that patients with dual growing rods had fewer complications, especially distraction failure in MCGR, than those with single growing rod. However, none of deformity correction, spinal growth, or other complications differed between single and dual growing rods. Therefore, we believe that dual growing rods do not provide strong advantages over single growing rod in the treatment of EOS.

Re-evaluating consensus and uncertainty among treatment options for early onset scoliosis: a 10-year update

PURPOSE

Consensus and uncertainty in early onset scoliosis (EOS) treatment were evaluated in 2010. It is currently unknown how treatment preferences have evolved over the past decade. The purpose of this study was to re-evaluate consensus and uncertainty among treatment options for EOS patients to understand how they compare to 10 years ago.

METHODS

11 pediatric spinal surgeons (similar participants as in 2010) were invited to complete a survey of 315 idiopathic and neuromuscular EOS cases (same cases as in 2010). Treatment options included the following: conservative management, distraction-based methods, growth guidance/modulation, and arthrodesis. Consensus was defined as ≥ 70% agreement, and uncertainty was < 70%. Associations between case characteristics and consensus for treatments were assessed via chi-squared and multiple regression analyses. Case characteristics associated with uncertainty were described.

RESULTS

Eleven surgeons [31.7 ± 7.8 years of experience] in the original 2010 cohort completed the survey. Consensus for conservative management was found in idiopathic patients aged ≤ 3, whereas in 2010, some of these cases were selected for surgery. There is currently consensus for casting idiopathic patients aged 1 or 2 with moderate curves, whereas in 2010, there was uncertainty between casting and bracing. Among neuromuscular cases with consensus for surgery, arthrodesis was chosen for patients aged 9 with larger curves.

CONCLUSION

Presently, preferences for conservative management have increased in comparison to 2010, and casting appears to be preferred over bracing in select infantile cases. Future research efforts with higher levels-of-evidence should be devoted to elucidate the areas of uncertainty to improve care in the EOS population.

LEVEL OF EVIDENCE

Level V.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Level V-expert opinion.

Unmatched rod contouring at the proximal end predisposes to occurrence of junctional kyphosis in early-onset scoliosis patients undergoing traditional growing rods treatment

STUDY DESIGN

A retrospective case series.

OBJECTIVE

To investigate whether unmatched rod contouring at the proximal end predisposed to the occurrence of proximal junctional kyphosis (PJK) in early-onset scoliosis (EOS) patients after traditional growing rods (TGR) treatment. TGR treatment has become a mainstay of treatment for EOS patients. PJK is one of the most common alignment-related complications.

METHODS

A consecutive series of EOS patients who had undergone TGR treatment were retrospectively reviewed. They were divided into PJK and non-PJK groups according to the occurrence of PJK or not. Demographic data, surgical strategies, and radiographic parameters were recorded and compared between groups. Proximal junctional angle (PJA) was defined as the angle between the caudal endplate of the UIV and the cephalad endplate of the second supradjacent vertebra above the UIV, while proximal rod contouring angle (PRCA) was defined as the angle of proximal rod contouring, which was represented by the angle between the cephalad endplate of the UIV and the caudal endplate of the second vertebra caudal to the UIV. Unmatched proximal rod contouring was regarded if the postoperative PRCA-PJA difference was greater than 5°.

RESULTS

This study finally included 73 patients. The mean age at the index surgery was 6.5 ± 2.2 years (range, 2-10 years). Mean follow-up lasted 5.0 ± 1.7 years (range, 2-9 years). They received mean 4.6 ± 1.6 lengthening procedures. There were 13 patients who were observed with PJK (18%). In comparison with the non-PJK group, the PJK group showed a larger preoperative major curve (82 ± 21° vs 70 ± 17°, P = 0.041) and global kyphosis (57 ± 6° vs. 44 ± 15°, P = 0.044). In addition, the PJK group had significantly larger postoperative PJA (10 ± 3 vs. 5 ± 3, P<0.001) and greater postoperative PJA-PRCA (6 ± 3 vs. 3 ± 3, P = 0.031). The proportion of patients with unmatched proximal rod contouring in PJK group was significantly higher than that in the non-PJK group (69% vs. 25%). Multiple logistic regression showed that preoperative GK>50°, postoperative PJA>10 and postoperative unmatched proximal rod contouring were the risk factors in predicting PJK after TGR treatment.

CONCLUSION

Approximately 18% EOS patients experienced PJK after TGR treatment. Unmatched proximal rod contouring may be an independent risk factor of PJK occurrence, in addition to greater preoperative GK and larger postoperative PJA.

LEVEL OF EVIDENCE: 3

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

Background

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

Methods

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

Results

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

Conclusion

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

Effects of combined adjustable Halo-pelvic fixation brace on cervical spine alignment in patients with severe rigid spinal deformity

Objective

To evaluate the effect of continuous traction with a combined adjustable Halo-pelvic fixation brace on the cervical spine alignment in patients with severe rigid spinal deformity and analyze its related factors.

Methods

We conducted a retrospective cohort study of 21 patients with severe rigid spinal deformity treated in our department between 2015 and 2019. All subjects received combined adjustable Halo-pelvic fixation brace traction before secondary orthopedic surgery. The influence of the Halo-pelvic fixation brace on the cervical spine alignment was evaluated by measuring the parameters of lateral cervical X-ray at three time points: before traction, at the end of traction, and 6 months after orthopedic surgery. The correlation between parameter changes and total traction duration was analyzed to explore factors influencing cervical alignment.

Results

The C2L-C7L angle was 22.40 ± 15.91° before traction, which decreased to 5.91 ± 6.78° at the end of traction but increased to 14.51 ± 10.07° after orthopedic surgery (BT vs ET p < 0.005, ET vs AOS p < 0.005, BT vs AOS p < 0.005). Accordingly, C2L-C7U angle, C2L-C6L angle, C2L-C6U angle, C2L-C5L angle, C7 or T1 slope, C2-C7 SVA, SCA, C2-T1 Ha, C0 slope, and C0-C2 angle also changed similarly to C2L-C7L angle. Furthermore, moderate correlation was observed between C2L-C7L angle and total traction volume (r = 0.563, p = 0.008) and SCA and traction duration (r = 0.525, p = 0.015). However, no significant correlation was found between other cervical alignment parameters and total traction volume and traction duration.

Conclusions

The continuous traction of a combined adjustable Halo-pelvic fixation brace can affect the cervical spine alignment of patients with severe rigid spinal deformity and straighten the physiological curvature of the cervical spine. However, the sagittal alignment gradually recovers after the traction, without any adverse effects on the orthopedic surgery and global balance after the operation; therefore, this apparatus is worthy of wide application.

How much does depth matter? Magnetically controlled growing rod distraction directly influenced by rod tissue depth

PURPOSE

Magnetically controlled growing rod (MCGR) for the treatment of early-onset scoliosis (EOS) is a relatively innovative technique. MCGR benefits over traditional growing rods are known but limitations and complications are being revealed. The purpose of this study was to examine the importance of tissue depth on rod lengthening.

METHODS

A single-institution retrospective review of 72 MCGR patients was performed. Ultrasound measured rod distraction. Differences in programmed and actual distraction, and complications were recorded. Tissue depths and achieved length were averaged and used to construct a regression to account for variability.

RESULTS

Percentage of std and offset orientation rod lengthening relative to the programmed distraction was inversely proportional to rod depth (std R = 0.50, p = 0.002) (offset R = 0.60, p < 0.001). Expected std rod lengthening achieved decreased by 1.46%/mm depth. Expected offset rod lengthening achieved decreased by 1.68%/mm depth. 28 pts (38.9%) sustained complications. Age, sex, BMI, standard tissue depth, and/or offset tissue depth had no predictive ability with respect to complications sustained (overall model R = 0.31, p = 0.36).

CONCLUSION

In a series of EOS surgical patients treated with MCGRs, the relationship between percentage of programmed lengthening achieved as well as total lengthening was inversely proportional to tissue depth of the rod. There was a trend towards increasing frequency of complications recorded with decreasing tissue depth though this was not significant. These data can help with surgical planning during MCGR placement.

Minimally Invasive Surgery for Neuromuscular Scoliosis: Results and Complications at a Minimal Follow-up of 5 Years

STUDY DESIGN

A prospective study.

OBJECTIVE

The aim of this study was to report the results of an alternative technique to growing rods (GR) for neuromuscular scoliosis using a minimally invasive fusionless surgery with a minimum of 5 years' follow-up.

SUMMARY OF BACKGROUND DATA

Conservative treatment is not effective in progressive neuromuscular scoliosis. Early surgery using GR is increasingly advocated to control the deformity while preserving spinal and thoracic growth before arthrodesis. These techniques still provide a high rate of complications.

METHODS

The technique relies on a bilateral double rod sliding instrumentation anchored proximally by four hooks claws and distally to the pelvis by iliosacral screws through a minimally invasive approach. The clinical and radiological outcomes of 100 consecutive patients with neuromuscular scoliosis who underwent this fusionless surgery with a minimum follow-up of 5 years were reviewed.

RESULTS

6.5 ± 0.7 years after initial surgery, six patients were lost of follow-up and 11 died of unrelated raison. Of the 83 remaining patients at latest follow-up, mean Cobb angle was stable to 35.0° which correspond to 61% correction of the initial deformation. Mean pelvic obliquity was 29.6° (0.3°-80.0°) preoperatively and 7.2 (0.2°-23.5°) at latest follow-up. Correction of the hyper kyphosis remained stable. Skeletal maturitywas reached in 42 of 83 patients (50.6%). None of these patients has required spinal fusion. The global complication rate was 31.3%.

CONCLUSION

The outcomes of this minimally invasive fusionless technique at 5 years follow-up showed a stable correction of spinal deformities and pelvic obliquity over time, with a reduced rate of complication. The arthrodesis was not required for all patients at skeletal maturity. This technique could be a good alternative to arthrodesis for neuromuscular scoliosis.Level of Evidence: 3.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Outcomes and Complications in Management of Congenital Myopathy Early-Onset Scoliosis

BACKGROUND

Congenital myopathies (CMs) are complex conditions often associated with early-onset scoliosis (EOS). The purpose of this study was to investigate radiographic outcomes in CM patients undergoing EOS instrumentation as well as complications. Secondarily, we sought to compare these patients to a population with higher prevalence, cerebral palsy (CP) EOS patients.

METHODS

This is a retrospective study of a prospectively collected multicenter registry. The registry was queried for EOS patients with growth-sparing instrumentation (vertical expandable prosthetic titanium ribs, magnetically controlled growing rods, traditional growing rod, or Shilla) and a CM or CP diagnosis with minimum 2 years follow-up. Outcomes included major curve magnitude, T1-S1 height, kyphosis, and complications.

RESULTS

Sixteen patients with CM were included. Six (37.5%) children with CM experienced 11 complications by 2 years. Mean major curve magnitude for CM patients was improved postoperatively and maintained at 2 years (P<0.01), with no significant increase in T1-S1 height or maximum kyphosis(P>0.05). Ninety-seven patients with CP EOS were included as a comparative cohort. Fewer CP patients required baseline respiratory support compared with CM patients (20.0% vs. 92.9%, P<0.01). Fifty-four (55.7%) CP patients experienced a total of 105 complications at 2 years. There was no evidence that the risk of complication or radiographic outcomes differs between cohorts at 2 years, though CP EOS patients experienced significant improvement in all measurements at 2 years.

CONCLUSIONS

EOS CM children face a high risk of complication after growing instrumentation, with similar curve correction and risk of complication to CP patients.

LEVEL OF EVIDENCE

Level III.

Two-staged posterior osteotomy surgery in complex and rigid congenital scoliosis in younger than 10 years old children

Background

Congenital scoliosis caused by failure of multiply vertebral segmentation with concave fused rib or unsegmented bar combined with contralateralhemivertebra is usually rigid and produces enormous asymmetric growth. Fusionless techniques have less advantage and come with some complications. Paucity of data was reported for children with complex congenital scoliosis using two-staged osteotomy surgery.

Methods

From 2006 to 2016, 11 patients less than 10 years old undergoing two staged osteotomy surgery for complex rigid congenital scoliosis were retrospectively reviewed. The analysis included age at initial surgery, second surgery and at the latest follow-up, and complications. Changes in coronal major curve, thoracic kyphosis, lumbar lodorsis, apex vertebra translation, T1-T12 length, T1-S1 length, trunk shift, and SVAwere included in radiological evaluation.

Results

In all, the mean follow-up was 72.5 ± 23.8 (42 to 112) months. The mean flexibility of the spine was 17.4 and 17.8 % before two surgeries. The mean age at the initial surgery was 6.6 ± 2.6 (2.5–10) years. The mean fusion level was 4.6 ± 1.3 (2 to 6) segments. The mean scoliosis improved from 67.4° to 23.7° after initial surgery and was 17.4° at the latest follow-up. The average increase of T1-S1 length was 0.92 cm per year. No patients had neurological complications.

Conclusions

Two-staged osteotomy surgery including hemivertebrae resection or Y-shaped osteotomy can achieve good radiological and clinical outcomes without severe complications. This procedure can be an option of treatment for complex congenital scoliosis.

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.

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

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

How to Select the Lower Instrumented Vertebra in Traditional Growing Rods Index Surgery

BACKGROUND

There are still no consensus criteria on how to select the lower instrumented vertebra (LIV) for traditional growing rods (TGRs) at index surgery. The aim was to evaluate whether the criteria used for adolescent idiopathic scoliosis fusion adapts to early onset scoliosis (EOS).

METHODS

Retrospective analysis of prospectively longitudinal collected data in a consecutive cohort of patients with EOS treated with TGR, expanding from index surgery to 2 years after graduation. The LIV was analyzed regarding its relation to the stable vertebra (SV), substantially touched vertebra (STV), and not STV (NSTV). Failure of LIV selection was considered when revision surgery with distal extension was needed during follow up, due to adding on (ΔLIV tilt > 10°).

RESULTS

A total of 25 patients met inclusion criteria. Mean age was 8.6 ± 3 (at index surgery), 15.1 ± 1.8 (at graduation), and 17.8 ± 1.6 (at final follow up). The most frequent LIV at index surgery was L3 (13/25); in 13 cases, STV was selected as LIV; in 7, it was NSTV; and in 5, SV on the standard postero-anterior radiographs. During follow up, a significant increase in the mean LIV tilt (P = .049) and distal junctional angle (P = .017) was found. Nine of the 25 patients (36%) developed adding on: 20% (1/5) of those with LIV at SV, 38.5% (5/13) at STV, and 42.8% (3/7) at NSTV. Of those 9 cases of adding on, only four needed distal extension (mean LIV tilt = 17.6°): 2 STV patients (15.4%), and 2 NSTV patients (28.6%). None of the patients with the LIV chosen at SV needed distal extension due to adding on.

CONCLUSIONS

The more cranial the selection of the LIV above the SV, the higher the risk of adding on and of revision surgery with distal extension during follow up. Saving motion segments could be justified by choosing STV as LIV because the need for distal extension is not high, and it can be scheduled during lengthening procedures or at graduation surgery.

LEVEL OF EVIDENCE

4.

CLINICAL RELEVANCE

Choosing the correct LIV in TGR index surgery is crucial to have a secure distal foundation, control and correct the deformity during growth, and save distal segments to allow growth and mobility.

Factors Related to Instrumentation Failure in Titanium Mesh Reconstruction for Thoracic and Lumbar Tumors: Retrospective Analysis of 178 Patients

Purpose

To investigate risk factors for instrumentation failure (IF) in titanium (Ti) mesh reconstruction for thoracic and lumbar tumors.

Patients and Methods

The clinical data of patients with thoracic or lumbar tumors who received Ti mesh reconstruction via the posterior approach in our hospital from 2013 to 2018 were analyzed retrospectively. The observation indexes included sex, age, BMI, the vertebra resection mode, the number of resected vertebral segments, application of bone cement, radiotherapy, chemotherapy, revision or primary surgery, and primary tumor metastasis. Correlations between these factors and IF were analyzed by Kaplan–Meier survival and logistics regression analyses.

Results

The 178 patients included 108 males and 70 females with a mean age of 48.09±16.21 (6–78) years and a mean follow-up period of 51.18 (24–90) months. The data showed that 17 patients (9.55%) were inflicted with IF, involving the thoracic vertebra in 11 cases, thoracolumbar vertebrae (T12–L1) in 2 cases, and lumbar vertebrae in 4 cases. The mean interval between surgery to IF was 35.18±14.17 (14–59) months. Univariate analysis showed that total vertebral body resection, the number of resected vertebral segments, radiotherapy and multiple tumor resection were potential factors for IF, while multivariate analysis showed that only total vertebral body resection, the number of resected vertebral segments and radiotherapy were independent factors.

Conclusion

Total vertebra resection, the number of resected vertebral segments (≥2) and radiotherapy before and after operation were significant risk factors related to IF.

Traditional Dual Growing Rod Technique in the Management of Early Onset Scoliosis and Its Effects on Spinal Growth and Lung Development: The Mid-Term Prospective Results

OBJECTIVE

The purpose of this study was to investigate the safety and effectiveness of the traditional dual growing rod (TDGR) technique, using only pedicle screws for fixation with more frequent lengthening while evaluating scoliosis correction in the growing spine, spinal growth rates, and the differences in lung volumes.

PATIENTS AND METHODS

In this single-centre prospective study, 27 patients with a follow-up of over three years were included in the study. Only pedicle screws were used as foundations for fixation. Routine lengthening procedures were performed every six months. Data were recorded including the age of initial surgery, gender, number of lengthenings, follow-up, and complications. The Cobb angle of the major curve, kyphosis angle, T1- S1 length, space available for lung (SAL) ratio, coronal and sagittal balance, and the height of all patients were measured and recorded preoperatively, immediately postoperatively, and finally before and after every lengthening.

RESULTS

The average follow-up time was 46.3 months (36-64 months). The correction rate was 69.5% for Cobb angle and 43.2% for kyphosis between preoperative and final follow-up period. The time between two lengthenings was 6.9 months, and the mean T1-S1 length increase was 1.78 cm per year. The SAL ratio increased from 0.885 preinitially to 0.985 at the last follow-up. The complication rate was determined as 9.6% in 187 procedures. Acceptable improvements were determined in the specified parameters with low complication rates with the use of this technique.

CONCLUSION

The TDGR technique with proximal and distal pedicle screws as anchors is a safe and effective treatment for deformity control in selected patients with early onset scoliosis (EOS). Repetitive surgical interventions are the negative side of this technique.

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

4.

Revision risk after pediatric spinal deformity surgery: a nationwide study with 2-year follow-up

BACKGROUND CONTEXT

Revision risk after pediatric spine surgery is not well established and varies between deformity etiologies.

PURPOSE

To report the 2-year revision risk following surgery for primary pediatric spinal deformity in a nationwide cohort and to evaluate potential risk factors and reasons for revision surgery.

DESIGN

Retrospective nationwide cohort study.

PATIENT SAMPLE

A national registry study of all pediatric spinal deformity patients undergoing surgery during 2006-2015 (n=1310).

OUTCOME MEASURES

Two-year revision risk.

METHODS

All patients ≤21 years of age undergoing spinal deformity surgery in Denmark during 2006-2015 were identified by procedure and diagnosis codes in the Danish National Patient Registry (DNPR). Data on revision surgery were retrieved from the DNPR. Patients were categorized in six groups according to etiology. Medical records were reviewed for reason for revision in all patients. Potential risk factors for revision were assessed with multiple logistic regression analyses and included age, etiology, sex, Charlson comorbidity index (CCI), and growth-preserving treatment.

RESULTS

Patients were categorized according to etiology: idiopathic deformity (53%), neuromuscular deformity (23%), congenital/structural deformity (9%), spondylolisthesis (7%), Scheuermann's kyphosis (5%), and syndromic deformity (3%). Of 1,310 included patients, 9.2% underwent revision surgery within 2 years and 1.5% was revised more than once. Median time to revision was 203 (interquartile range 35-485) days. The multivariable logistic regression found significantly higher odds ratio (OR) for revision in patients with growth-preserving treatment (OR=5.1, 95% confidence interval [CI] 2.6-10.1), congenital deformity (OR=2.7, 95% CI 1.3-5.3), spondylolisthesis (OR=3.5, 95% CI 1.9-6.7), Scheuermann kyphosis (OR=3.9, 95% CI 1.9-8.3), and CCI score ≥3 (OR=2.5 95% CI 1.1-5.6). The most common reason for revision was implant failure (32.5%) followed by residual deformity and/or curve progression (15.8%).

CONCLUSIONS

In this nationwide study, the 2-year revision risk after primary pediatric spinal deformity surgery is 9.2%. Risk factors for revision are etiology of congenital deformity, spondylolisthesis, Scheuermann kyphosis as well as patients with growth-preserving treatment and higher CCI. The most common reason for revision is implant failure.

The first magnetically controlled growing rod (MCGR) in the world - lessons learned and how the identified complications helped to develop the implant in the past decade: case report

Background

The first magnetically controlled growing rod (MCGR) was implanted in 2009. Since then multiple complications have been identified that have helped drive the development of the MCGR and its surgery. The aim of this report is to illustrate how identified complications in the first MCGR helped with developments in the past decade and to report a unique failure mechanism with stud fracture close to the barrel opening.

Case presentation

A 5-year old girl with a scoliosis of 58.5 degrees at T1–9 and 72.8 degrees at T9-L4 had a single MCGR inserted and anchored at T3–4 and L3–4. At postoperative 13 months the MCGR was noted to have lost of distraction between lengthening episodes due to unrestricted turning of the internal magnet. To prevent further loss of distraction, an external magnet was placed outside the skin to prevent the magnet from turning back. The overall balance was suboptimal and after the rod was fully distracted, proximal junctional kyphosis occurred. Subsequently, the MCGR was modified with an internal keeper plate to prevent loss of distraction and a dual set of these rods were implanted when the patient was 9 years old. Extension proximally to C7-T1 was done to manage the proximal junctional kyphosis. Her spinal balance improved and distractions continued. She subsequently developed add-on below and the piston rod was not aligned with the actuator. The lumbar spine was also observed to have autofusion. She subsequently had final fusion surgery performed at the age of 15 from C7-L4 leaving a residual tilt below to avoid fusion to the pelvis. The final extracted rod on the left side indicated the “crooked rod sign” on X-ray and rod dissections revealed a new failure mechanism of stud fracture close to the barrel opening. Body fluids and tissue may infiltrate the rod despite no obvious deformation or fractures resulting in hastened wearing of the threads.

Conclusions

There are various complications associated with MCGRs that are related to rod design and surgical inexperience. Repeated rod stalling is not recommended with potential stud fracture and “crooked rod sign”. Rotor stalling and thread wearing which indicates rod failure still require solutions.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL EVIDENCE

Level III-retrospective comparative.

TYPE OF EVIDENCE

Therapeutic.

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.

Comparing health-related quality of life and burden of care between early-onset scoliosis patients treated with magnetically controlled growing rods and traditional growing rods: a multicenter study

STUDY DESIGN

Multicenter retrospective cohort study.

OBJECTIVES

To compare pre-operative and post-operative EOSQ-24 scores in magnetically controlled growing rods (MCGR) and traditional growing rod (TGR) patients. Since the introduction of MCGR, early-onset scoliosis patients have been afforded a reduction in the number of surgeries compared to the TGR technique. However, little is known about (health-related quality of life) and burden of care outcomes between these surgical techniques.

METHODS

This is a retrospective cohort study using a multicenter registry on patients with EOS undergoing MCGR or TGR between 2008 and 2017. The EOSQ-24 was administered at preoperative and postoperative 2-year assessments. The EOSQ-24 scores were compared between MCGR and TGR as well as preoperatively and postoperatively within each procedure.

RESULTS

110 patients were analyzed in this study (TGR, N = 32; MCGR, N = 78). There were no significant differences in preoperative age, gender, etiology, main coronal curve or maximum kyphosis between TGR and MCGR groups. Patients with TGR had averaged 3.9 surgical lengthenings and MCGR had averaged 7.7 non-invasive lengthenings by the 2-year follow-up. When changes in preoperative to postoperative scores were compared, MCGR had more improvements in pain, emotion, child satisfaction and parent satisfaction than TGR although there were no statistical significance. When analyzed separately, MCGR cohort had improvement in scores for all four domains and four sub-domains; while, TGR cohort only had improvement in financial burden domain and pulmonary function sub-domain.

CONCLUSION

Although there was no statistical significance, the improvement in pain, emotion and satisfaction scores was larger in MCGR than TGR. Since these areas can be influenced more by mental well-being than other sub-domains, the results may prove our hypothesis that compared to TGR, MCGR with reduced number of surgeries have better psychosocial effects.

LEVEL OF EVIDENCE

III.

Improvement of Pulmonary Function Measured by Patient-reported Outcomes in Patients With Spinal Muscular Atrophy After Growth-friendly Instrumentation

BACKGROUND

Children with spinal muscular atrophy (SMA) sustain a progressive reduction in pulmonary function (PF) related to both muscular weakness and the concomitant effects of spinal deformity on the thorax. Growth-friendly instrumentation is commonly utilized for younger patients with scoliosis and SMA to halt the progression of spinal curvature, but its effect on PF in these patients has not previously been investigated. Using the change in Early Onset Scoliosis 24-Item Questionnaire (EOSQ-24) PF subdomain scores, the authors will investigate whether PF improves in patients with SMA after a growth-friendly intervention.

METHODS

This was a multicenter retrospective cohort study from 2 international registries of patients with SMA undergoing spinal deformity surgery from 2005 to 2015. Data collected were age, sex, degree of major coronal curve, type of growth-friendly construct, forced vital capacity (FVC), and EOSQ-24 scores at the patient's preoperative, 1-year postoperative, and 2-year postoperative visits. Differences in EOSQ-24 PF scores and FVC between baseline and postoperative assessment were examined by paired tests.

RESULTS

A total of 74 patients were identified (mean age, 7.6±2.3 y, major curve 68.1±22.4 degrees, 51.4% female individuals). The mean EOSQ-24 PF scores improved significantly from 70.6 preoperatively to 83.6 at 1 year (P=0.092) and 86.5 at 2 years postoperatively (P=0.020). The scores in patients with rib-based constructs showed steeper increases at 1-year assessments than those in patients with spine-based constructs. The mean paired FVC value decreased from 63.9% predicted preoperatively, to 57.6% predicted at 1 year postoperatively (P=0.035), and 61.9% predicted preoperatively, to 56.3% predicted at 2 years postoperatively (P=0.178).

CONCLUSIONS

Patients with SMA who received growth-friendly instrumentation did experience improvements in PF as measured by EOSQ-24 assessing the caregivers' perception. Given the uncertain reliability of PFTs in this young population, EOSQ-24 is an important tool for measuring improvements in health-related quality of life.

LEVEL OF EVIDENCE

Level III-retrospective study.

Is rod diameter associated with the rate of rod fracture in patients treated with magnetically controlled growing rods?

INTRODUCTION

Few risk factors for fracture in magnetically controlled growing rods (MCGR) have been identified. We hypothesize an increased rate of rod fracture in small diameter rods compared to large diameter rods in patients with early-onset scoliosis (EOS). The purpose of this study was to determine the association between the diameter of MCGR constructs and the rate of rod fracture.

METHODS

Patients with EOS who underwent MCGR implantation-primary or conversion-from 2013 to 2018 were identified from two registries including 40 centers. Rod diameter sizes greater than 5.0 mm or less than or equal to 5.0 mm were defined as "Large" and "Small" rods, respectively. Only dual-rod constructs were included. The primary outcome measure collected was rod fracture at any point in treatment up to the most recent follow-up. Cox regression was utilized for unequal follow-up to compare rate of breakage at the last follow-up between cohorts.

RESULTS

527 patients with 1,054 rods were included. 552 (52.4%) rods had a diameter of less than or equal to 5.0 mm and 461 (43.7%) rods had a diameter of greater than 5.0 mm. 41 (3.9%) rods were missing a recorded rod diameter and were not included in the analysis to determine the association between the rate of fracture and rod diameter. 20 (1.9%) total rod fractures occurred: 9 (1.6%) rods with diameters of ≤ 5.0 mm, 10 (2.2%) rods with diameters of > 5.0 mm, and 1 uncategorized rod (p = 0.529). No difference in the rate of rod fracture or survival distribution was found between rod diameters of > 5.0 mm and ≤ 5.0 mm even after stratification by ambulatory status, major coronal curve, weight, or location of anchors.

DISCUSSION

Rod fracture appears to be a rare event in dual MCGR constructs and rod diameter does not seem to be associated with the incidence or rate of rod fracture. Surgeons may consider other criteria for selecting rod diameter in their patients such as patient size, amount of surgical correction, single vs. dual constructs, and risk of hardware prominence.

Systematic investigation of metallosis associated with magnetically controlled growing rod implantation for early-onset scoliosis

AIMS

To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod.

METHODS

This was a prospective observational study of patients with early onset scoliosis (EOS) treated with MCGRs and undergoing rod exchange who were consecutively recruited between February 2019 and January 2020. Ten patients were recruited (mean age 12 years (SD 1.3); 2 M:8 F). The configurations of the MCGR were studied to reveal the distraction mechanisms, with crucial rod parts being the distractable piston rod and the magnetically driven rotor inside the barrel of the MCGR. Metal-on-metal contact in the form of ring-like wear marks on the piston was found on the distracted portion of the piston immediately outside the barrel opening (BO) through which the piston rod distracts. Biopsies of paraspinal muscles and control tissue samples were taken over and away from the wear marks, respectively. Spectral analyses of the rod alloy and biopsies were performed to reveal the metal constituents and concentrations. Histological analyses of the biopsies were performed with haematoxylin and eosin staining.

RESULTS

Titanium (Ti), vanadium (V), and neodymium (Nd) concentrations in the biopsies taken near the wear marks were found to be significantly higher than those in the control tissue samples. Significantly increased Nd concentrations were also found in the tissues near the barrel of the MCGR. Chronic inflammation was revealed by the histological studies with fibrosis and macrophage infiltration. Black particles were present within the macrophages in the fibrotic tissues.

CONCLUSION

Ti and V were generated mainly at the BO due to metal-on-metal contact, whereas the Nd from the rotor of the MCGR is likely released from the BO during distraction sessions. Phagocytotic immune cells with black particles inside raise concern regarding the long-term implications of metallosis. Cite this article: Bone Joint J 2020;102-B(10):1375-1383.

Diverse approaches to scoliosis in young children

Management of scoliosis in young children needs a comprehensive approach because of its complexity. There are many debatable points; however, only serial casting, growing rods (including traditional and magnetically controlled) and anterior vertebral body tethering will be discussed in this article.Serial casting is a time-gaining method for postponing surgical interventions in early onset scoliosis, despite the fact that it has some adverse effects which should be considered and discussed with the family beforehand.Use of growing rods is a growth-friendly surgical technique for the treatment of early onset spine deformity which allows chest growth and lung development. Magnetically controlled growing rods are effective in selected cases although they sometimes have a high number of unplanned revisions.Anterior vertebral body tethering seems to be a promising novel technique for the treatment of idiopathic scoliosis in immature cases. It provides substantial correction and continuous curve control while maintaining mobility between spinal segments. However, long-term results, adverse effects and their prevention should be clarified by future studies. Cite this article: EFORT Open Rev 2020;5:753-762. DOI: 10.1302/2058-5241.5.190087.

Growth-preserving instrumentation in early-onset scoliosis patients with multi-level congenital anomalies

STUDY DESIGN

Retrospective.

OBJECTIVES

To assess final outcomes in patients with early-onset scoliosis (EOS) who underwent growth-preserving instrumentation (GPI). Various types of growth-preserving instrumentation (GPI) are frequently employed, but until recently had not been utilized long enough to assess final outcomes.

METHODS

GPI "graduates" with multi-level congenital curves were identified. Graduation was defined as a final fusion or 5 years of follow-up without planned future surgeries. Outcomes included radiographic parameters and complications.

RESULTS

26 patients were included. 11 had associated diagnoses; eight had fused ribs. 17 were treated with traditional growing rods, seven with vertically expandable prosthetic ribs, and two with Shilla procedures. The mean GPI spanned 12.3 levels including 10.7 motion segments, age at index surgery was 5.5 years, treatment spanned 7.5 years, and follow-up was 9.2 years. 24 patients underwent final fusion. Mean major curve decreased from 73° to 49° with index surgery (p < 0.01) and remained unchanged through a final follow-up. Final major curve was < 40° in 9 patients (35%), 40°-60° in 11 patients (42%), and > 60° in 6 patients (23%). None worsened throughout treatment. Mean T1-T12 height increased 2.4 cm with index surgery (p = 0.02) and 5.4 cm total (p < 0.01). T1-T12 height increased in all patients and was ultimately < 18 cm in 10 patients (38%), 18-22 cm in 10 patients (38%), and > 22 cm in 6 patients (23%). On average, there were 2.6 complications per patient, including 1.7 implant failures. 12 patients (46%) experienced ≥ 3 complications; four patients (15%) experienced none.

CONCLUSION

We observed successful prevention of deformity progression but substantial residual deformity among GPI graduates with multi-level congenital EOS. Most coronal curve correction was attained during GPI implantation; thoracic height improved throughout treatment. While some favorable results were found, treatment strategies allowing improved deformity correction would be valuable for this challenging population.

LEVEL OF EVIDENCE

Therapeutic-III.

Bone age assessment based on deep convolution neural network incorporated with segmentation

PURPOSE

Bone age assessment is not only an important means of assessing maturity of adolescents, but also plays an indispensable role in the fields of orthodontics, kinematics, pediatrics, forensic science, etc. Most studies, however, do not take into account the impact of background noise on the results of the assessment. In order to obtain accurate bone age, this paper presents an automatic assessment method, for bone age based on deep convolutional neural networks.

METHOD

Our method was divided into two phases. In the image segmentation stage, the segmentation network U-Net was used to acquire the mask image which was then compared with the original image to obtain the hand bone portion after removing the background interference. For the classification phase, in order to further improve the evaluation performance, an attention mechanism was added on the basis of Visual Geometry Group Network (VGGNet). Attention mechanisms can help the model invest more resources in important areas of the hand bone.

RESULT

The assessment model was tested on the RSNA2017 Pediatric Bone Age dataset. The results show that our adjusted model outperforms the VGGNet. The mean absolute error can reach 9.997 months, which outperforms other common methods for bone age assessment.

CONCLUSION

We explored the establishment of an automated bone age assessment method based on deep learning. This method can efficiently eliminate the influence of background interference on bone age evaluation, improve the accuracy of bone age evaluation, provide important reference value for bone age determination, and can aid in the prevention of adolescent growth and development diseases.

Comparison of Effectiveness between Cobalt Chromium Rods versus Titanium Rods for Treatment of Patients with Spinal Deformity: A Systematic Review and Meta-Analysis

Background

Biomechanical properties of rods determine their ability to correct spinal deformity and prevention of postoperative sagittal and coronal changes. The selection of a proper rod material is crucial due to their specific mechanical properties that influence the surgical outcome. The purpose of this study is to compare the effectiveness of cobalt chromium rods versus titanium rods for the treatment of spinal deformity by a systematic review and meta-analysis.

Methods

PubMed, EMBASE, and the Cochrane library were searched for observational and biomechanical studies comparing cobalt chromium and titanium rods in terms of correction rate, thoracic kyphosis, lumbar lordosis, incidence of rod fracture, fatigue life of contoured rod, bending stiffness of rods, and occurrence of proximal junctional kyphosis. The demographic data and mean values of outcomes of interest were extracted from each group and compared by their mean difference as an overall outcome measure. The Review Manager software (RevMan 5.3) was utilized at a 95% significance level.

Results

Eleven eligible studies with 641 participants for 7 observational studies and 35 samples for 4 biomechanical studies were identified. There were no significant differences between cobalt chromium and titanium rods in the correction rate of spinal deformity. Postoperative thoracic kyphosis was well restored in the cobalt chromium group with statistical significance (p value = 0.009). The incidence of rod fracture was high in titanium rods compared to cobalt chromium rods with significant difference (p value = 0.0001). Proximal junctional kyphosis occurs more in the cobalt chromium group with a significant difference (p value = 0.0009). No statistical significance between two materials in terms of lumbar lordosis, fatigue of life, and bending stiffness of rods.

Conclusion

The cobalt chromium rod is better than titanium rod for effective correction of spinal deformity and postoperative stability of the spine. However, the use of cobalt chromium rods is associated with increased risk of proximal junctional kyphosis.

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.

Unplanned return to operation room (OR) following growing spinal constructs (GSCs) in early onset scoliosis (EOS)-a multi-centric study

PURPOSE

To evaluate the incidence and risk factors associated with the unplanned return to OR in EOS.

METHODS

Medical records of 51 patients of EOS operated at three different centres using various types of GSCs were evaluated for complications requiring unplanned surgeries. Data were analysed to find out rate of unplanned surgeries in relation to the aetiology, age and Cobb angle at index surgery, type of implant, cause of unplanned surgery, and management required.

RESULTS

Out of 51 patients, three did not meet inclusion criteria. Forty-eight patients of EOS operated by GSCs with a mean age of 6.7 years (range 2-12 years) with an average follow-up of 67.3 months were studied. There were 30 congenital, 10 idiopathic, 4 syndromic, and 4 neuromuscular cases. Thirty-nine out of 48 patients had one or more unplanned surgeries on follow-up (81.25%). Out of total 248 surgeries following index procedure, 82 were unplanned surgeries (33.06%), including 53 implant revisions, 12 implant-removal, 14 debridement, and 2 flaps. The common complications were 24.14% rod/screw breakage, 42.53% anchor pull-out, 16.09% infections, 6.90% wound dehiscence, and 4.6% neuro deficits. Unplanned surgeries were significantly higher in syndromic (58.8%) and neuromuscular (52.9%) than congenital (27.2%) and idiopathic (37.8%) cases (p < 0.05). Age at index procedure < 5 years had higher unplanned surgeries than age > 5 years (2.5 and 1.23 per patient, respectively,  p < 0.05). Type of implant and initial Cobb angle did not significantly affect the rate of unplanned surgeries (p  > 0.05) CONCLUSION: GSCs in EOS require a frequent revisit to operation room which should be well understood by the surgeon and parents.

Growth-Friendly Implants With Rib Clawing Hooks as Proximal Anchors in Early-Onset Scoliosis

STUDY DESIGN

Retrospective study.

OBJECTIVES

This study retrospectively evaluates the outcome of the surgical treatment of early-onset scoliosis with proximal clawing rib fixation in hybrid growing-rod constructs. The study examines spinal deformity correction with spinal growth maintenance, and the complications associated with this technique.

METHOD

A hybrid rib construct surgery with serial lengthening was utilized for the treatment of 71 patients. Mean age at surgery was 66.6 months and mean time for follow-up was 43.9 months.

RESULTS

The coronal Cobb angle in patients fell from 63.1° preoperatively to 51.6° at the last follow-up, with a correction of 16.8%. The sagittal Cobb angle fell from 66.7° preoperatively to 38° at the last follow-up, with a correction of 42.6%. Coronal balance fell from 22.8° preoperatively to 22.3°, and sagittal balance fell from 35.4 mm preoperatively to 24.39 mm. T1-S1 spine height increased from 248.7 mm preoperatively to 282.4 mm, with a mean change of 1.13 cm per year. No neurological complications were detected.

CONCLUSION

Surgical management for early-onset scoliosis using proximal clawing rib fixation technique is a good choice in terms of safety, ease of placing the proximal anchors, ability to use more than one form of instrumentation, and a lower complication rate.

Understanding Respiratory Restrictions as a Function of the Scoliotic Spinal Curve in Thoracic Insufficiency Syndrome: A 4D Dynamic MR Imaging Study

BACKGROUND

Over the past 100 years, many procedures have been developed for correcting restrictive thoracic deformities which cause thoracic insufficiency syndrome. However, none of them have been assessed by a robust metric incorporating thoracic dynamics. In this paper, we investigate the relationship between radiographic spinal curve and lung volumes derived from thoracic dynamic magnetic resonance imaging (dMRI). Our central hypothesis is that different anteroposterior major spinal curve types induce different restrictions on the left and right lungs and their dynamics.

METHODS

Retrospectively, we included 25 consecutive patients with thoracic insufficiency syndrome (14 neuromuscular, 7 congenital, 4 other) who underwent vertical expandable prosthetic titanium rib surgery and received preimplantation and postimplantation thoracic dMRI for clinical care. We measured thoracic and lumbar major curves by the Cobb measurement method from anteroposterior radiographs and classified the curves as per Scoliosis Research Society (SRS)-defined curve types. From 4D dMRI images, we derived static volumes and tidal volumes of left and right lung, along with left and right chest wall and left and right diaphragm tidal volumes (excursions), and analyzed their association with curve type and major curve angles.

RESULTS

Thoracic and lumbar major curve angles ranged from 0 to 136 and 0 to 116 degrees, respectively. A dramatic postoperative increase in chest wall and diaphragmatic excursion was seen qualitatively. All components of volume increased postoperatively by up to 533%, with a mean of 70%. As the major curve, main thoracic curve (MTC) was associated with higher tidal volumes (effect size range: 0.7 to 1.0) than thoracolumbar curve (TLC) in preoperative and postoperative situation. Neither MTC nor TLC showed any meaningful correlation between volumes and major curve angles preoperatively or postoperatively. Moderate correlations (0.65) were observed for specific conditions like volumes at end-inspiration or end-expiration.

CONCLUSIONS

The relationships between component tidal volumes and the spinal curve type are complex and are beyond intuitive reasoning and guessing. TLC has a much greater influence on restricting chest wall and diaphragm tidal volumes than MTC. Major curve angles are not indicative of passive resting volumes or tidal volumes.

LEVEL OF EVIDENCE

Level II-diagnostic.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

IV.

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

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

INTRODUCTION

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

HYPOTHESIS

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

STUDY DESIGN

Systematic literature review.

METHODS

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

RESULTS

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

CONCLUSION

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

Posterior vertebral column resection for rigid proximal thoracic kyphoscoliosis with broken growing rods in a patient with Desbuquois dysplasia

STUDY DESIGN

Case report.

OBJECTIVE

To describe the importance of preoperative halo-gravity traction and posterior vertebral column resection (PVCR) for severe proximal thoracic kyphoscoliosis associated with Desbuquois dysplasia, after breakage of a growing rod construct. Desbuquois dysplasia is a rare, autosomal recessive chondrodysplasia characterized by short stature, joint laxity, kyphoscoliosis, and characteristic facial dysmorphism. Our 8-year-old patient developed severe, progressive, infantile-onset kyphoscoliosis and had been initially treated with Vertical Expandable Prosthetic Titanium Rib (VEPTR) rods. She subsequently underwent growing rod placement, but the eventual rod fracture resulted in a severe angular kyphosis.

METHODS

Clinical and radiographic case review.

RESULTS

The broken implants were removed, and she was treated with 2.5 months of preoperative halo-gravity traction. She then underwent a T4 PVCR and C7-L4 instrumented posterior spinal fusion. The patient had an uneventful postoperative course without any neurologic problems. Two years postoperatively, correction was well maintained with appropriate alignment and balance without implant breakage.

CONCLUSION

To our knowledge, this is the first report of treatment of spinal deformity associated with Desbuquois dysplasia. Our results suggest that preoperative halo-gravity traction and PVCR are safe and efficacious techniques for severe rigid kyphoscoliosis in the cervicothoracic region associated with broken growing rods in a patient with Desbuquois dysplasia.

LEVEL OF EVIDENCE

Level IV.

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

STUDY DESIGN

Case series.

OBJECTIVE

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

SUMMARY OF BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

4.

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.

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

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

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.

Vertebral Growth Around Distal Instrumented Vertebra in Patients With Early-Onset Scoliosis Who Underwent Traditional Dual Growing Rod Treatment

STUDY DESIGN

Retrospective radiographic study.

OBJECTIVE

To investigate the growth of the vertebrae around distal instrumented vertebra (DIV) in patients with early-onset scoliosis (EOS) who underwent dual growing rod (DGR) treatment.

SUMMARY OF BACKGROUND DATA

Previous studies indicated that DGR was likely to preserve or even stimulate the spinal growth. However, report pertaining to the effect of growing rod on the growth of individual vertebral body is rare.

METHODS

The EOS patients treated with DGR who had at least four lengthenings and 5-year follow-up were enrolled. Spine radiographs at index surgery and final follow-up were reviewed. The height, width, and depth of vertebral body from DIV-2 to DIV+2, and the height of the adjacent intervertebral space (IVS) were measured. The percentage of growth was calculated.

RESULTS

Thirty-one patients (mean age, 6.2 ± 2.5 years old) met the inclusion criteria, 74.2% (23/31) of whom were female. The average follow-up was 6.2 years (range, 5.0-10.4 yr). The measured vertebrae were divided into DIV group (n = 65), DIV- group (DIV-1 and DIV-2, n = 60), and DIV+ group (DIV+1 and DIV+2, n = 47). There were 33, 90, and 78 measured IVSs in DIV, DIV-, and DIV+ group, respectively. The total percentage growth of vertebral height was significantly higher in DIV- group than that in DIV and DIV+ groups (56.6 ± 20.3% vs. 45.6 ± 18.0% and 42.7 ± 16.2%, respectively, P ≤ 0.001). The vertebrae in DIV- group also had the highest annual height growth rate (8.7 ± 2.6% vs. 7.0 ± 2.4% and 6.6 ± 2.0%, respectively, P ≤ 0.001). A significant decrease of IVS height was observed in DIV- and DIV groups (P ≤ 0.001).

CONCLUSION

Traditional DGR with periodical distraction stimulated the longitudinal growth of the two segments immediately above DIV in patients with EOS. DGR technique had a negative effect on the development of intervertebral discs within distracted levels.

LEVEL OF EVIDENCE

3.