Diverse approaches to scoliosis in young children

LIV selection in 'tweener' patients treated with magnetically controlled growing rods vs. posterior spinal fusion

PURPOSE

The purpose of this study was to compare the LIV selection in 'tweener' patients treated with MCGR or PSF.

METHODS

A multicenter pediatric spine database was queried for ambulatory patients ages 8-11 years treated by MCGR or PSF with at least 2-year follow-up. The relationship between the LIV and preoperative spinal height, curve magnitude, and implant type were assessed. The relationship between the touched vertebrae (TV), the last substantially touched vertebrae (LSTV), the stable vertebrae (SV), and the LIV were evaluated.

RESULTS

One hundred and fifty-nine patients met inclusion criteria. Preoperative curve magnitude was similar between groups (MCGR 68 ± 19.0° vs. PSF 66 ± 17.2°, p = 0.6). Preoperative curve magnitude was associated with LIV, as larger curves were associated with a more caudal LIV (p = 0.0004). Distribution of the LIV was more varied in PSF compared to MCGR. L3 was the LIV in 43% of MCGR patients compared to 27% of PSF patients. A thoracic LIV was more common in the PSF group (PSF 13% vs. MCGR 1.2%, p = 0.0038). The LIV was cephalad to the SV in 68% of PSF compared to 48% of MCGR patients (p = 0.02).

CONCLUSION

The majority of LIV selection in 'tweener' patients was at L3 or below regardless of surgical strategy, likely driven by curve magnitude. However, 'tweener' patients treated with PSF had more cephalad LIV selections compared to patients treated with MCGR. Potential LIV differences should be considered when selecting MCGR vs. PSF in 'tweener' patients.

LEVEL OF EVIDENCE

III.

Outcome of distraction-based growing rods at graduation: a comparison of traditional growing rods and magnetically controlled growing rods

INTRODUCTION

Distraction-based growing rods have been considered as an alternative surgical option for the operative treatment of EOS. TGR has been challenged by MCGR, which is reported to have the advantage of non-invasive lengthening with fewer planned returns to theatre. This study explores the radiographic outcomes, Unplanned Returns to the Operating Room (UPROR) and complication profile of both the procedures at the end of the planned growing rod treatment with either TGR or MCGR.

METHODS

We included all the EOS cases from the PSSG database that underwent either TGR or MCGR with spine-based proximal anchors, followed up to the time of graduation. Any crossover or hybrid procedures were excluded. 549 patients (409 TGR and 140 MCGR) were eligible for review. We measured the coronal curve magnitude, Kyphosis, T1-T12, T1-S1 and L1-S1 lengths at 4 time points (before and after the index surgery and before and after the definitive surgery).

RESULTS

The TGR group were slightly younger at the time of the index procedure (7 years for TGR vs. 8.5 years for MCGR, p < 0.001). We noted an improvement in all radiological parameters after the growing rod implantation. The spinal lengths increased through the lengthening period, while the coronal curve magnitude and the kyphosis increased. The kyphosis normalized following the final fusion, the coronal curve magnitude reduced further with a further increase in spinal lengths. The final follow-up from the time of the index implantation to the definitive surgery was 5.1 years (IQR 3.8) in TGR and 3.5 years (IQR 1.65) in the MCGR groups. The total number of complications was fewer in the MCGR group. The overall risk of UPROR was lower in the MCGR group and implant breakage was less in the MCGR group by 4.7 times.

CONCLUSIONS

This study confirms the equivalence of both the distraction-based growing rods systems from the radiological stand-point, during the lengthening phase and at the time of the definitive surgery. The TGR was more kyphogenic during the lengthening period. The complications and UPROR were fewer in the MCGR groups.

Anterior Vertebral Body Tethering (AVBT) in the Treatment of Adolescent Idiopathic Scoliosis: A Retrospective Study

Background/Objectives: Anterior Vertebral Body Tethering (AVBT) is a relatively novel minimally invasive surgical technique for the treatment of adolescent idiopathic scoliosis (AIS) that enables deformity correction of the spine diminishing vertebral motion reduction caused by the standard posterior spinal fusion approach. This paper reports the introduction of a new technical variant of AVBT, with the aim of evaluating its effectiveness on the correction of both axial and coronal spinal deformity. Methods: A single-centre single-surgeon retrospective cohort study was conducted. AVBTs were performed between 2020 and 2024. Radiographical values, surgical details, and complications of 67 patients affected by AIS were compared before surgery, immediately after surgery, and at the most recent follow-up. Results: Postoperative results have revealed a statistically significant coronal curve correction of 29.85% in the main thoracic (MT) curves (from mean preoperative width of 54.81 ± 11.86° to 38.45 ± 10.19°) and of 26.93% in the thoracolumbar (TL/L) curves (from 35.15 ± 11.83° to 25.69 ± 10.50°) in line with that obtained by the standard technique. Coronal correction at the most recent follow-up was maintained. Postoperative axial rotation reduction was found to be statistically significant in the main thoracic (MT) curves (from mean Nash-Moe value of 1.84 ± 0.71 to 1.36 ± 0.73), with a further decrease at the most recent follow-up compared with preoperative values. Improvement in other radiographical measures did not reach statistical significance and the complication rate was comparable to the standard technique. Conclusions: The extent of coronal correction in patients treated with the proposed modified AVBT technique is satisfactory and in line with results from studies testing the standard AVBT technique. The findings of this study seem to suggest that this technical variant of AVBT is effective in the correction of both axial and coronal deformity, with a surgical complication rate comparable to the standard technique.

Autofusion in early-onset scoliosis growing constructs: occurrence, risk factors, and impacts

PURPOSES

Autofusion (AF) during growing rod (GR) instrumentation for early-onset scoliosis (EOS) has been reported, but AF incidence, causation, and clinical implications remain unknown. This article aims to (1) quantify frequency and severity of AF, (2) determine risk factors for AF, and (3) assess the influence of AF on final curve correction and spinal lengthening.

METHODS

EOS patients were prospectively enrolled (2016-2021). Patients underwent evaluation, GR implantation, lengthenings, and posterior spinal fusion (PSF). Cobb angle and spinal length measurements were collected. AF was assessed and graded, with grades I-II being low-grade and III-V being high-grade. Exposure analysis quantified risk factors' impact via odds ratios and Pearson regression correlates. Statistical significance was p ≤ 0.05 or ≥ 0.95.

RESULTS

28 patients, with variable EOS diagnoses, were included. On average, GR were implanted at 8.54-year-old and lengthened over 4.66 years. 53.6% of patients received magnetically controlled GR (MCGR) and 46.4% traditional GR (TGR). The average construct bridged 13.4 levels. Over the lengthening period, for all indications, patients averaged 2.9 total open procedures. Curves corrected from 68.5º preoperatively to 35.3º after index GR to 35.6º after PSF. Spinal length increased from 30.0 cm preoperatively to 33.9 cm after index GR to 39.5 cm after PSF. AF grading was: 28.6% Grade I, 25.0% Grade II, 17.9% Grade III, 25.0% Grade IV, and 3.6% Grade V. Idiopathic EOS tended to have lower AF grades (p = 0.37). AF risk factors included GR age < 8 (10.4×, p = 0.01), any interval open procedures (6.3×, p = 0.05), and residual curve > 30º after index GR (13.7×, p = 0.02). Protective factors included preoperative spinal length of > 30.0 cm (0.11×, p = 0.01) and index MCGR (0.16×, p = 0.03). Maintenance of Cobb angles from index GR through PSF was relatively better in low-grade patients (p = 0.08). Spinal length gained was no different between low- and high-grade AF (p = 0.50).

CONCLUSIONS

This largest-to-date evaluation found AF is nearly ubiquitous in GR constructs, but with variable severity. Both risk factors and protective factors coincide with AF. Ultimately, even in high-grade AF, curve correction was maintained, and spinal lengthening was achieved.

LEVEL OF EVIDENCE

Level II-prospective cohort study.

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

Background

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

Methods

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

Results

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

Conclusion

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

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

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

Anterior Vertebral Body Tethering for Scoliosis Patients With and Without Skeletal Growth Remaining: A Retrospective Review With Minimum 2-Year Follow-Up

BACKGROUND

Anterior vertebral body tethering (AVBT) has been approved for skeletally immature (IM) adolescent idiopathic scoliosis patients, but the role of AVBT in patients with minimal remaining skeletal growth is controversial. The purpose of this study was to compare minimum 2-year (YR2) outcomes in skeletally IM patients vs those with minimal remaining skeletal growth.

METHODS

Patients with single thoracic AVBT were grouped by their preoperative (PR) skeletal maturity: IM (n = 16, Risser 0-2) vs mature (M, n = 19, Risser 3-5). Outcomes were assessed at PR, first erect (FE), and YR2. Median (range) was compared with nonparametric tests (P < 0.05).

RESULTS

The PR age was 12.5 (9-16) vs 15 (12-18) years with major Cobb 51° (36°-69°) and 49° (40°-69°) for IM and M, respectively. At FE, there was no difference in correction; however, at YR2, the IM group yielded a lower residual curve (15° [-16° to 38°] vs 29° [12°-42°], P = 0.008). Thoracolumbar/lumbar curves were corrected without group differences. Clinically successful correction (<35°) (15 [94%] vs 15 [79%]) and suspected cord breakages (2 [13%] vs 2 [12%]) were similar at YR2. Two overcorrections occurred, both in IM patients. Scoliosis Research Society-22 outcomes at final follow-up were similar between groups. No revision reoperations or conversions to spinal fusion were needed.

CONCLUSIONS

Skeletally IM patients benefit from greater growth-modulated curve correction than M patients, however, at the increased risk of overcorrection. M patients maintained clinically significant correction at latest follow-up. Longer-term follow-up is required to determine durability of outcomes for patients undergoing AVBT who have minimal remaining growth at the time of index surgery.

CLINICAL RELEVANCE

This study is relevant to spine surgeons, spine physiotherapists, and patients with idiopathic scoliosis. It offers evidence of clinical correction of scoliosis in mature patients.

LEVEL OF EVIDENCE: 3

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The application of finite element analysis to determine the optimal UIV of growing-rod treatment in early-onset scoliosis

Objectives: To analyze the stress distribution in the proximal vertebral body and soft tissue of dual growing-rod (GR) with different upper instrumented vertebra (UIV) to determine the optimal UIV.

Methods: A ten-year-old male EOS case treated with GR was selected. Based on spiral computed tomography (CT) scanning performed in 0.6 mm thick slices, a finite element model (FEM) of the preoperative state (M0, the original spine state) of the patient was created. Subsequently, four models with different UIV fixations were numerically analyzed by FEM, including M1 (UIV = T1, i.e., the upper-end vertebrae (UEV) of the upper thoracic curve), M2 (UIV = T2), M3 (UIV = T3) and M4 (UIV = T4, i.e., the lower end vertebrae (LEV) of the upper thoracic curve). Displacement and maximum stress in the proximal vertebral body and soft tissue were measured and compared among the five models.

Results: The spine model was fixed with the sacrum, and the gravity conditions were imposed on each vertebral body according to the research of Clin and Pearsall. The results are as follows:M4 model has the largest overall displacement, while M1 has the least displacement among the four models. Except M2, the maximum normalized stress of UIV increases with the downward movement of UIV. M1 has the lowerest annulus fibrosus stress and highest joint capsule stress, which is characterized by the vertebrae backward leaning, while M4 is the opposite. The supraspinous ligament stress of M3 and M4 is significantly higher than that of M1 and M2. This suggests that UIV downshift increases the tendency of the proximal vertebral bodies to bend forward, thereby increasing the tension of the posterior ligaments (PL).

Conclusion: The UIV of the GR is recommended to be close to the UEV of the upper thoracic curve, which can reduce the stress of the proximal PL, thereby reducing the occurrence of proximal junctional kyphosis (PJK).

Early-onset scoliosis: a narrative review

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

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

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

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

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

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

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Congress Theme: Harmonisation and Diversity

Cite this article: EFORT Open Rev 2020;5:742-742. DOI: 10.1302/2058-5241.5.200202.