Delayed paraparesis after posterior spinal fusion for congenital scoliosis: a case report.

INTRODUCTION: Although multimodal intraoperative neuromonitoring (IONM), which has high sensitivity and specificity, is typically performed during spinal deformity surgery, neurological status may deteriorate with delay after surgical maneuvers. Here, we report a rare case of delayed postoperative neurological deficit (DPND) that was not detected by IONM during posterior spinal fusion (PSF) for congenital scoliosis. CASE PRESENTATION: A 14-year-old male presented with congenital scoliosis associated with T3 and T10 hemivertebrae. Preoperative Cobb angle of proximal thoracic (PT) and main thoracic (MT) curves were 50° and 41°, respectively. PSF (T1-L1) without hemivertebrectomy was performed, and the curves were corrected to 31° and 21° in the PT and MT curves, respectively, without any abnormal findings in IONM, blood pressure, or hemoglobin level. However, postoperative neurological examination revealed complete loss of motor function. A revision surgery, release of the curve correction by removing the rods, was immediately performed and muscle strength completely recovered on the first postoperative day. Five days postoperatively, PSF was achieved with less curve correction (36° in the PT curve and 26° in the MT curve), without postoperative neurological deficits. DISCUSSION: Possible mechanisms of DPND in our patient are spinal cord ischemia due to spinal cord traction caused by scoliosis correction and spinal cord kinking by the pedicle at the concave side. Understanding the possible mechanisms of intra- and postoperative neural injury is essential for appropriate intervention in each situation. Additionally, IONM should be continued to at least skin closure to detect DPND observed in our patient.

Comparison and Evaluation of the Accuracy for Thoracic and Lumbar Pedicle Screw Fixation in Early-Onset Congenital Scoliosis Children.

BACKGROUND: Compared to adult scoliosis, correcting scoliosis in children often presents greater challenges. This is attributed to two key factors. Firstly, it involves accounting for the growth potential of children. Secondly, the thinner pedicles in children can complicate screw insertion, particularly when dealing with existing deformities. The utilization of intraoperative navigation technology offers a modest improvement in the precision of screw placement but does come with the drawback of increased radiation exposure. The aim of this study is to investigate and assess the accuracy of manually inserting pedicle screws in the thoracic and lumbar spine to rectify deformities in children with early-onset congenital scoliosis. METHODS: In this retrospective study, 26 hospitalized patients diagnosed with early-onset congenital scoliosis between December 2014 and December 2019 were selected. The cohort comprised 16 boys and 10 girls, aged between 2 and 10 years, with an average age of 4.68 ± 2.42 years. Pedicle screw fixation was applied in the segment spanning from T1 to L5. Pedicle screws were inserted manually, guided by the positioning of the C-arm and anatomical markers. The assessment of pedicle screw placement was based on the distance of penetration into the medial, lateral, or anterior bone cortex of the vertebral body, including the pedicle, categorized into three grades: Grade 1 (placement <2 mm), Grade 2 (placement between 2-4 mm), and Grade 3 (placement >4 mm). Grade 1 indicates accurate pedicle screw placement, while Grades 2 and 3 signify abnormal pedicle screw placement. Complications related to pedicle screw insertion were also recorded, both during and after the surgical procedure. RESULTS: A total of 173 pedicle screws were inserted in this study, with an average of 6.65 screws per patient. Accurate screw placement was achieved in 143 cases (82.7%), while 30 pedicle screws were found to be abnormal. Among the abnormal screws, 24 were categorized as Grade 2 (13.9%), and 6 as Grade 3 (3.5%). Grade 2 abnormalities were distributed across 20 thoracic vertebrae and 4 lumbar vertebrae, while Grade 3 abnormalities affected 5 thoracic vertebrae and 1 lumbar vertebra. When comparing the lumbar and thoracic vertebral regions, a significant difference in the rate of abnormal screw placement was observed (χ2 = 5.801, p < 0.05). The rate of abnormal screw placement was higher in the thoracic vertebral region with abnormal vertebral bodies than in the lumbar vertebral regions. Furthermore, a statistically significant difference in the rate of abnormal screw placement was found between the concave and convex sides (χ2 = 23.047, p < 0.05). The concave side of the abnormal vertebral body had a higher rate of abnormal screw placement (55.6%, 15/27) compared to the convex side (20.1%, 7/34), and this difference was statistically significant (p < 0.05). Throughout the intraoperative and postoperative follow-up period, spanning from 12 to 56 months, only one patient experienced issues with wound healing, and no complications related to pedicle screw placement occurred, such as hemopneumothorax, pedicle fracture, nerve root injury, aortic injury, screw loosening, pullout or breakage, or spinal cord injury. CONCLUSIONS: In children under 10 years of age with early-onset congenital scoliosis, the freehand placement of thoracic and lumbar pedicle screws demonstrates a high level of accuracy. Moreover, complications associated with pedicle screw insertion are infrequent following surgery. It is advisable to exercise caution when placing pedicle screws in thoracic vertebral bodies and morphologically abnormal vertebral bodies, with particular attention to the concave side when screw placement is required in these regions.

A Study of Polish Family with Scoliosis and Limb Contractures Expands the MYH3 Disease Spectrum.

A disease associated with malfunction of the MYH3 gene is characterised by scoliosis, contractures of the V fingers, knees and elbows, dysplasia of the calf muscles, foot deformity and limb length asymmetry. The aim of this study was to identify the cause of musculoskeletal deformities in a three-generation Polish family by exome sequencing. The segregation of the newly described c.866A>C variant of the MYH3 gene in the family indicates an autosomal dominant model of inheritance. The detected MYH3 variant segregates the disease within the family. The presented results expand the MYH3 disease spectrum and emphasize the clinical diagnostic challenge in syndromes harbouring congenital spine defects and joint contractures.

Analysis of the factors affecting the loss of correction effect in patients with congenital scoliosis after one stage posterior hemivertebrae resection and orthosis fusion.

BACKGROUND: To analyze the factors affecting the loss of correction effect in patients with congenital scoliosis after one stage posterior hemivertebra resection, orthosis, fusion and internal fixation. METHODS: Thirty-nine patients with congenital scoliosis (CS) who underwent one-stage posterior hemivertebra resection, orthosis, fusion and internal fixation were retrospectively included in Hebei Children's Hospital General demographic information of patients was collected. Preoperative and postoperative imaging indicators were compared, Including cobb Angle of the main curvature of the spine, segmental Cobb Angle, compensatory cephalic curve, compensatory curve on the caudal side, segmental kyphosis, coronal balance, sagittal balance, thoracic kyphosis, lumbar lordosis, and apical vertebra translation. Correlation analysis is used to evaluate the factors affecting the loss of judgment and correction effect, and the correlation indicators are included in the multi-factor Logistics regression. RESULTS: In terms of radiographic indicators in the coronal plane, compared to preoperative values, significant improvements were observed in postoperative Cobb Angle of main curve (8.00°±4.62° vs. 33.30°±9.86°), Segmental Cobb angle (11.87°±6.55° vs. 31.29°±10.03°), Compensatory cephalic curve (6.22°±6.33° vs. 14.75°±12.50°), Compensatory curve on the caudal side (5.58°±3.43° vs. 12.61°±8.72°), coronal balance (10.95 mm ± 8.65 mm vs. 13.52 mm ± 11.03 mm), and apical vertebra translation (5.96 mm ± 5.07 mm vs. 16.55 mm ± 8.39 mm) (all P < 0.05). In the sagittal plane, significant improvements were observed in Segmental kyposis Angle (7.60°±9.36° vs. 21.89°±14.62°, P < 0.05) as compared to preoperative values. At the last follow-up, Segmental kyphosis Angle (6.09°±9.75° vs. 21.89°±14.62°, P < 0.05), Thoracic kyphosis (26.57°±7.68° vs. 24.06°±10.49°, P < 0.05) and Lumbar lordosis (32.12°±13.15° vs. 27.84°±16.68°, P < 0.05) had statistical significance compared with the preoperative department. The correlation analysis showed that the correction effect of the main curve Cobb angle was correlated with fixed segment length (rs=-0.318, P = 0.048), postoperative segment Cobb angle (rs=-0.600, P < 0.001), preoperative apical vertebra translation (rs = 0.440, P = 0.005), and spinal cord malformation (rs=-0.437, P = 0.005). The correction effect of segmental kyphosis was correlated with age (rs = 0.388, P = 0.037). The results of the multivariate logistic regression analysis revealed that postoperative segmental Cobb angle > 10° (OR = 0.011, 95%CI:0.001-0.234, P = 0.004), associated spinal cord anomalies (OR = 24.369, 95%CI:1.057-561.793, P = 0.046), and preoperative apical translation > 10 mm (OR = 0.012, 95%CI:0.000-0.438, P = 0.016) were influential factors in the progression of the main curve Cobb angle. CONCLUSION: The one-stage posterior hemivertebra resection and short-segment corrective fusion with internal fixation are effective means to treat congenital scoliosis. However, attention should be paid to the loss of correction and curve progression during follow-up. Patients with spinal cord malformation and a large preoperative apical vertebra translation have a greater risk of losing the correction after surgery.

The incidence and interrelationship of hemivertebra and concomitant cardiac abnormalities in congenital scoliosis.

BACKGROUND: Congenital scoliosis(CS) is associated with multiple organs defect, and cardiac abnormalities have been reported commonly associated with CS. Hemivertebra is caused by the failure of vertebral formation, which is a major constitute of CS. Till now, few studies focus on the incidence and interrelationship of hemivertebra and concomitant cardiac abnormalities in congenital scoliosis. We aimed to analyze the cardiac defect in CS patients with or without hemivertebra, and further explore the incidence of cardiac defect between different types of hemivertebra. METHODS: The ultrasonic cardiography (UCG) results of surgically treated congenital scoliosis (CS) patients between 2015 and 2018 were retrospectively analyzed. Patients were divided into hemivertebra group and non-hemivertebra group according to preoperative CT. Patients with hemivertebra was further divided into sub-group by single/multiple or fully/partially/mixed segmented hemivertebra. Demographic information, radiographic data and cardiac abnormalities were statistically compared between groups. RESULTS: A total of 329 patients were analyzed, including 216 patients with hemivertebra and 113 patients without hemivertebra. UCG results were abnormal in 89 cases (27.1%), including 41 males(12.5%) and 48 females(14.6%). Hemivertebra group had comparable incidence of cardiac abnormalities with non-hemivertebra group (p = 0.517). No significant difference in the incidence of UCG abnormalities between single and multiple hemivertebra group (P = 0.246). Binary logistic regression analysis showed that female sex with multiple hemivertebra was a risk factor for abnormal UCG (P = 0.009, OR = 3.449). Cardiac abnormalities was comparable among fully, partially and mixed segmented hemivertebra group(P = 0.264). In abnormal UCG, 33 patients with hemivertebra had non-valvular abnormalities, and 48.5% (16/33) were septal defects. 28 patients had valvular abnormalities, most of them were mitral valve abnormalities, especially mitral valve redundancy, prolapse and insufficiency(82.1%, 23/28). No significant difference between the incidence of non-valvular and valvular abnormalities in patients with hemivertebra (P = 0.581). CONCLUSIONS: The incidence of abnormal UCG results was approximately 28.2% in CS patients with hemivertebra. Female patients with multiple hemivertebra had a higher risk of UCG abnormalities. Mitral valve abnormalities were the most common abnormality of UCG found in CS patients with hemivertebra. TRIAL REGISTRATION: retrospectively registered.

Musculoskeletal defects associated with myosin heavy chain-embryonic loss of function are mediated by the YAP signaling pathway.

Mutations in MYH3, the gene encoding the developmental myosin heavy chain-embryonic (MyHC-embryonic) skeletal muscle-specific contractile protein, cause several congenital contracture syndromes. Among these, recessive loss-of-function MYH3 mutations lead to spondylocarpotarsal synostosis (SCTS), characterized by vertebral fusions and scoliosis. We find that Myh3 germline knockout adult mice display SCTS phenotypes such as scoliosis and vertebral fusion, in addition to reduced body weight, muscle weight, myofiber size, and grip strength. Myh3 knockout mice also exhibit changes in muscle fiber type, altered satellite cell numbers and increased muscle fibrosis. A mass spectrometric analysis of embryonic skeletal muscle from Myh3 knockouts identified integrin signaling and cytoskeletal regulation as the most affected pathways. These pathways are closely connected to the mechanosensing Yes-associated protein (YAP) transcriptional regulator, which we found to be significantly activated in the skeletal muscle of Myh3 knockout mice. To test whether increased YAP signaling might underlie the musculoskeletal defects in Myh3 knockout mice, we treated these mice with CA3, a small molecule inhibitor of YAP signaling. This led to increased muscle fiber size, rescue of most muscle fiber type alterations, normalization of the satellite cell marker Pax7 levels, increased grip strength, reduced fibrosis, and decline in scoliosis in Myh3 knockout mice. Thus, increased YAP activation underlies the musculoskeletal defects seen in Myh3 knockout mice, indicating its significance as a key pathway to target in SCTS and other MYH3-related congenital syndromes.

Incidence of cardiac anomalies in congenital vertebral deformity: systematic review and meta-analysis of 2910 patients.

PURPOSE: This study aimed to analyze the overall incidence of cardiac abnormalities in patients with congenital scoliosis and the possible influencing factors. METHODS: PubMed, Embase, and Cochrane Library were searched for relevant studies. The quality of the studies was assessed independently by two authors using the methodological index for nonrandomized studies (MINORS) criteria. The following data were extracted from the included studies: bibliometric data, number of patients, number of patients with cardiac anomalies, gender, types of deformity, diagnostic method, type of cardiac anomaly, location, and other associated anomalies. The Review Manager 5.4 software was used to group and analyze all the extracted data. RESULTS: This meta-analysis included nine studies and identified that 487 of 2,910 patients with congenital vertebral deformity had cardiac anomalies diagnosed by ultrasound (21.05%, 95% CI of 16.85-25.25%). The mitral valve prolapse was the most frequent cardiac anomaly (48.45%) followed by an unspecified valvular anomaly (39.81) and an atrial septal defect (29.98). A diagnosis of cardiac anomalies was highest in Europe (28.93%), followed by USA (27.21%) and China (15.33%). Females and formation defects were factors significantly associated with increased incidence of cardiac anomalies: 57.37%, 95% CI of 50.48-64.27% and 40.76%, 95% CI of 28.63-52.89%, respectively. Finally, 27.11% presented associated intramedullary anomalies. CONCLUSIONS: This meta-analysis revealed that the overall incidence of cardiac abnormalities detected in patients with congenital vertebral deformity was 22.56%. The incidence rate of cardiac anomalies was higher in females and those with formation defects. The study offers guidance for ultrasound practitioners to accurately identify and diagnose the most common cardiac anomalies.

Medium-term and Long-term Follow-up Surgical Outcomes of the 1-stage Posterior-only Lumbosacral Hemivertebra Resection With Short-segment Fusion in Children.

BACKGROUND: The objective of this study was to evaluate the medium-term and long-term surgical outcomes of the 1-stage posterior-only lumbosacral hemivertebra resection with short-segment fusion in children. METHODS: This retrospective chart review included 21 children with congenital scoliosis due to lumbosacral hemivertebra who received 1-stage posterior-only hemivertebra resection with short-segment fusion from 2012 to 2016 with at least 5 years of follow-up. Standing anteroposterior and lateral radiographs of the spine were compared preoperatively, postoperatively, and at last follow-up. Radiographic evaluation included measured changes in segmental scoliosis and lordosis, compensatory scoliosis, thoracic kyphosis, lumbar lordosis, trunk shift, and sagittal spinopelvic alignment. RESULTS: There were 12 boys and 9 girls with a mean age of 6.5±3.2 years. The mean follow-up period was 6.7±1.3 years. The mean fusion level was 2.7±0.9 segments. The mean segmental scoliosis was 29±6 degrees preoperatively, 9±3 degrees (correction rate of 71%) postoperatively ( P <0.05), and 7±3 degrees (correction rate of 76%) at the latest follow-up. The compensatory curve of 26±12 degrees was spontaneously corrected to 14±8 degrees (correction rate of 47%) at last follow-up ( P <0.05). Trunk shift was significantly improved on both coronal (53%) and sagittal (56%) planes after surgery ( P 0.05) and stable at follow-up. The sagittal spinopelvic alignment was balanced in all cases. There were no neurological or infectious complications. CONCLUSIONS: It is safe and effective to perform 1-stage posterior-only lumbosacral hemivertebra resection with short-segment fusion, which can significantly correct the segmental scoliosis, prevent the compensatory curve progress and improve the trunk shift. This strategy also can save motion segments and avoid long lumbar fusion. Medium-term and long-term follow-up outcomes are satisfactory. LEVEL OF EVIDENCE: Level III.

Overview of Gene Special Issue "Genetic Conditions Affecting the Skeleton: Congenital, Idiopathic Scoliosis and Arthrogryposis".

In this Special Issue of Genes entitled "Genetic Conditions Affecting the Skeleton: Congenital, Idiopathic Scoliosis and Arthrogryposis", evidence is presented which suggests that congenital, idiopathic scoliosis, and arthrogryposis share similar overlapping, but also distinct etiopathogenic mechanisms, including connective tissue and neuromuscular mechanisms [...].

Bi-allelic MYH3 loss-of-function variants cause a lethal form of contractures, pterygia, and spondylocarpotarsal fusion syndrome 1B.

Arthrogryposis is a consequence of reduced fetal movements and arises due to environmental factors or underlying genetic defects, with extensive genetic heterogeneity. In many instances, the genes responsible are involved in neuromuscular function. Missense variants in the gene encoding embryonic myosin heavy chain (MYH3) usually cause distal arthrogryposis. Recently, mono-allelic or bi-allelic MYH3 variants have been associated with contractures, pterygia, and spondylocarpotarsal fusion syndrome 1 (CPSFS1A and CPSFS1B). Here we describe three fetuses presenting in the second trimester with a lethal form of arthrogryposis and pterygia and harbouring bi-allelic variants in MYH3. One proband was compound heterozygous for a missense change and an extended splice site variant, a second proband had a homozygous frameshift variant, and a third proband was homozygous for a nonsense variant. Minigene assays performed on the first fetus showed that the missense and extended splice site variants resulted in aberrant splicing, likely resulting in near complete loss of full-length MYH3 transcript. This study shows that loss of MYH3 is associated with a lethal arthrogryposis phenotype and highlights the utility of minigene assays to assess splicing.

Predictors of perioperative blood loss in primary posterior hemivertebra resection for pediatric patients with congenital scoliosis.

Several studies have elucidated the risk factors of intraoperative bleeding. However, the total blood loss (visible and hidden loss) and related risk factors were seldom reported. In this study, we aimed to identify predictors of massive blood loss in posterior hemivertebra resection for pediatric patients. Clinical records were retrospectively reviewed for 108 pediatric patients who underwent primary posterior hemivertebra resection and spinal fusion for congenital scoliosis from June 2017 to June 2019. Intraoperative blood loss was recorded and hidden blood loss was calculated by deducting the intraoperative loss from the total blood loss calculated using specific formula. Perioperative information was collected for multivariable linear regression analysis to determine the independent risk factors of the blood loss. The mean total blood loss was 575.0 ± 318.0 ml during the perioperative period, accounting for 42.1% of the estimated blood volume. The intraoperative and hidden loss were 337.6 ± 179.5 ml and 237.4 ± 204.8 ml, respectively, accounting for 58.7 and 41.3% of the total loss. Multivariable linear regression indicated that age, preoperative Cobb angle, operative time, and number of fused levels were independent risk factors of the total blood loss. Patients with operative time ≥145 minutes, fused levels ≥4, and preoperative Cobb angle ≥40° have an increased risk of massive blood loss. The perioperative blood loss of surgery for congenital scoliosis was considerable, with a high percentage of hidden blood loss. Patients with severe deformity, more fused levels, and longer operative time had higher risk of massive blood loss.

Bioinformatics Analysis and Experimental Verification Identify Downregulation of COL27A1 in Poor Segmental Congenital Scoliosis.

BACKGROUND: Congenital scoliosis (CS) represents the congenital defect disease, and poor segmental congenital scoliosis (PSCS) represents one of its types. Delayed intervention can result in disability and paralysis. In this study, we would identify the core biomarkers for PSCS progression through bioinformatics analysis combined with experimental verification. METHODS: This work obtained the GSE11854 expression dataset associated with somite formation in the GEO database, which covers data of 13 samples. Thereafter, we utilized the edgeR of the R package to obtain DEGs in this dataset. Then, GO annotation, KEGG analyses, and DO annotation of DEGs were performed by "clusterProfiler" of the R package. This study performed LASSO regression for screening the optimal predicting factors for somite formation. Through RNA sequencing based on peripheral blood samples from healthy donors and PSCS cases, we obtained the RNA expression patterns and screen out DEGs using the R package DESeq2. The present work analyzed COL27A1 expression in PSCS patients by the RT-PCR assay. RESULTS: A total of 443 genes from the GSE11854 dataset were identified as DEGs, which were involved in BP associated with DNA replication, CC associated with chromosomal region, and MF associated with ATPase activity. These DEGs were primarily enriched in the TGF-ß signaling pathway and spinal deformity. Further, LASSO regression suggested that 9 DEGs acted as the signature markers for somite formation. We discovered altogether 162 DEGs in PSCS patients, which were involved in BP associated with cardiac myofibril assembly and MF associated with structural constituent of muscle. However, these 162 DEGs were not significantly correlated with any pathways. Finally, COL27A1 was identified as the only intersected gene between the best predictors for somite formation and PSCS-related DEGs, which was significantly downregulated in PSCS patients. CONCLUSION: This work sheds novel lights on DEGs related to the PSCS pathogenic mechanism, and COL27A1 is the possible therapeutic target for PSCS. Findings in this work may contribute to developing therapeutic strategies for PSCS.

Surgical outcomes in children under 10 years old in the treatment of congenital scoliosis due to single nonincarcerated thoracolumbar hemivertebra: according to the age at surgery.

PURPOSE: Hemivertebra is one of the common pathogenesis of congenital scoliosis. The timing of operation is undefined. Our study compared the surgical outcomes in children under age 10 years with scoliosis due to single nonincarcerated thoracolumbar hemivertebra according to the age at surgery. METHODS: From January 2009 to August 2017, we retrospectively investigated 34 consecutive cases of congenital scoliosis treated by posterior hemivertebra resection and fusion with pedicle screw fixation. All cases were divided into two groups according to the age at surgery and followed-up for at least 2 years, group 1 (≤ 5 years old), and group 2 (5 to 10 years old). RESULTS: The mean Cobb angle of the main curve was improved from 48.58° to 15.53° (68.05%) in group 1, and from 43.73° to 11.33° (75.43%) in group 2. The segmental curve was improved from 44.16° to 11.53° (74.64%) in group 1, and the segmental curve was consistent with the main curve in group 2. The mean segmental kyphosis was improved from 27.50° to 8.42° (67.40%) in group 1, and from 29.00° to 5.00° (84.73%) in group 2. Five patients developed distal adding-on, and four patients were found proximal junctional kyphosis during the follow-up. CONCLUSION: Not all the deformities caused by single nonincarcerated thoracolumbar hemivertebra would progress greatly with the spinal growth. No significant statistical differences were found in the coronal and sagittal correction rate between the two groups. A limited delayed surgery after 5 years but before 10 years of age with close follow-up can achieve satisfied results.

Novel FGFR1 Variants Are Associated with Congenital Scoliosis.

FGFR1 encodes a transmembrane cytokine receptor, which is involved in the early development of the human embryo and plays an important role in gastrulation, organ specification and patterning of various tissues. Pathogenic FGFR1 variants have been associated with Kallmann syndrome and hypogonadotropic hypogonadism. In our congenital scoliosis (CS) patient series of 424 sporadic CS patients under the framework of the Deciphering disorders Involving Scoliosis and COmorbidities (DISCO) study, we identified four unrelated patients harboring FGFR1 variants, including one frameshift and three missense variants. These variants were predicted to be deleterious by in silico prediction and conservation analysis. Signaling activities and expression levels of the mutated protein were evaluated in vitro and compared to that of the wild type (WT) FGFR1. As a result, the overall protein expressions of c.2334dupC, c.2339T>C and c.1261A>G were reduced to 43.9%, 63.4% and 77.4%, respectively. By the reporter gene assay, we observed significantly reduced activity for c.2334dupC, c.2339T>C and c.1261A>G, indicating the diminished FGFR1 signaling pathway. In conclusion, FGFR1 variants identified in our patients led to only mild disruption to protein function, caused milder skeletal and cardiac phenotypes than those reported previously.

Identification of Copy Number Variants in a Southern Chinese Cohort of Patients with Congenital Scoliosis.

Congenital scoliosis (CS) is a lateral curvature of the spine resulting from congenital vertebral malformations (CVMs) and affects 0.5-1/1000 live births. The copy number variant (CNV) at chromosome 16p11.2 has been implicated in CVMs and recent studies identified a compound heterozygosity of 16p11.2 microdeletion and TBX6 variant/haplotype causing CS in multiple cohorts, which explains about 5-10% of the affected cases. Here, we studied the genetic etiology of CS by analyzing CNVs in a cohort of 67 patients with congenital hemivertebrae and 125 family controls. We employed both candidate gene and family-based approaches to filter CNVs called from whole exome sequencing data. This identified 12 CNVs in four scoliosis-associated genes (TBX6, NOTCH2, DSCAM, and SNTG1) as well as eight recessive and 64 novel rare CNVs in 15 additional genes. Some candidates, such as DHX40, NBPF20, RASA2, and MYSM1, have been found to be associated with syndromes with scoliosis or implicated in bone/spine development. In particular, the MYSM1 mutant mouse showed spinal deformities. Our findings suggest that, in addition to the 16p11.2 microdeletion, other CNVs are potentially important in predisposing to CS.

A retrospective cohort study on red blood cell morphology changes in pre-school age children under nitrous oxide anesthesia.

BACKGROUND: Megaloblastic anemia or bone marrow changes could occur after prolonged nitrous oxide inhalation via vitamin B12 inactivation related DNA synthesis impairment. Previous researches have studied hematological changes with nitrous oxide exposure, but only in adults or adolescents. Pre-school age children with active hematopoietic red bone marrow are more vulnerable to potential side effects of nitrous oxide and might experience growth impairment. The purpose of our study was to analyze red blood cell morphology changes under nitrous oxide anesthesia in pre-school age children. METHODS: One hundred thirty-six children under 5 years old scheduled for hemivertebra resection were analyzed. According to fresh gas type in anesthesia records, 71 children who received nitrous oxide in oxygen during anesthesia maintenance were categorized into the nitrous oxide group and the other 65 who received air in oxygen were the air group. Complete blood counts in perioperative period were assessed for anemia, macrocytosis, microcytosis, anisocytosis, hyperchromatosis and hypochromatosis. The peak value and change percentage were calculated for mean corpuscular volume and red cell distribution width. RESULTS: Forty-two children in the air group (64.6%) and 30 in the nitrous oxide group (42.3%) developed anemia (P = 0.009). None developed macrocytosis in both groups. Postoperative mean corpuscular volume peaked (mean [95% confidence interval]) at 83.7(82.9-84.4) fL, and 83.2(82.4-83.9) fL and postoperative red cell distribution width at 13.8% (13.4-14.2%), and 13.9% (13.6-14.2%) for the air group and the nitrous oxide group. Both the relative change of mean corpuscular volume (P = 0.810) and red cell distribution width (P = 0.456) were similar between the two groups. CONCLUSIONS: No megaloblastic red blood cell changes were observed with nitrous oxide exposure for 4 h in pre-school age children undergoing hemivertebra resection.

Posterior hemivertebra resection and short-segment fusion with lateral mass screws in congenital scoliosis: a novel strategy for the resource-limited setting.

BACKGROUND: Posterior hemivertebra resection and short-segment fusion with pedicle screws are an established treatment in congenital scoliosis, which require pediatric-specific instrumentation. The purpose of this study was to report the results of utilizing cervical lateral mass screws instead of pedicle screws in the treatment of congenital scoliosis in children younger than 5 years old. METHODS: In an IRB-approved retrospective chart review study, patients <5 years old with congenital scoliosis who underwent posterior hemivertebra resection and fusion with lateral mass screws from 2013 to 2017 were included. Demographic information, pre- and post-operative radiographs, complications, and outcomes were extracted from the charts. RESULTS: Twenty-three patients were included in the final analysis with a mean age of 40 months, of which 14 were female. Patients were followed for a mean of 51.3±13.2 months. The mean blood loss was 210ml, and patients were hospitalized for a mean of 4 days post-operatively. The correction rate of the main coronal curve, compensatory cranial curve, compensatory caudal curve, and segmental sagittal curve was 74.8%, 68%, 65.2%, and 68.9%, respectively. Three complications were observed: one intra-operative pedicle fracture, one case of implant failure, and one deep surgical-site infection, all of which were successfully managed. CONCLUSIONS: Our findings suggest that adult lateral mass screws can be used for transpedicular fixation of the thoracic and lumbar vertebrae in low-resource settings where pediatric-specific pedicle instruments are not readily available. The correction rate, outcomes, and complications are similar and comparable to pediatric-specific pedicle screws, in addition to being low-profile and less bulky compared to adult implants.

Intragenic Deletions in FLNB Are Part of the Mutational Spectrum Causing Spondylocarpotarsal Synostosis Syndrome.

Spondylocarpotarsal synostosis syndrome (SCT) is characterized by vertebral fusions, a disproportionately short stature, and synostosis of carpal and tarsal bones. Pathogenic variants in FLNB, MYH3, and possibly in RFLNA, have been reported to be responsible for this condition. Here, we present two unrelated individuals presenting with features typical of SCT in which Sanger sequencing combined with whole genome sequencing identified novel, homozygous intragenic deletions in FLNB (c.1346-1372_1941+389del and c.3127-353_4223-1836del). Both deletions remove several consecutive exons and are predicted to result in a frameshift. To our knowledge, this is the first time that large structural variants in FLNB have been reported in SCT, and thus our findings add to the classes of variation that can lead to this disorder. These cases highlight the need for copy number sensitive methods to be utilized in order to be comprehensive in the search for a molecular diagnosis in individuals with a clinical diagnosis of SCT.

Rib-based Distraction Device Implantation Before Age 3 Associated With Higher Unplanned Rate of Return to the Operating Room.

BACKGROUND: Surgical treatment of early-onset scoliosis (EOS) with rib-based implants such as the vertical expandable prosthetic titanium rib (VEPTR) is associated with a high rate of complications including surgical site infection, skin breakdown, and implant migration. Many of these complications warrant the need for unplanned reoperations, increasing the burden on an already vulnerable patient population, and introducing the further risk of infection. To provide insight into the risks of early intervention, we investigate the relationship between initial device implantation before the age of 3 and the rate of unplanned reoperation. METHODS: A retrospective review was performed of all patients at a single institution who had undergone VEPTR insertion for EOS with at least a 2-year follow-up from 2007 to 2016. Patients were stratified into the case-cohort (0 to 2 y of age) or the comparison cohort (3 to 10 y of age) based on age at the time of device implantation. Multivariate regression accounting for age and scoliosis etiology was performed to identify factors predictive of unplanned reoperation. RESULTS: A total of 137 of 185 patients treated with VEPTR were identified with 76 (56%) undergoing at least 1 unplanned reoperation during the study time period. There were 68 and 69 patients in the age 0- to 2-year and 3- to 10-year cohorts, respectively. Patients aged 0 to 2 years underwent a higher number of total procedures compared with those aged 3 to 10 (13.1±6.5 vs. 10.6±4.8, P=0.032). A significant difference was found in the rate of unplanned reoperation between the 2 cohorts with 44 (65%) patients aged 0 to 2 and 32 (46%) patients aged 3 to 10 undergoing at least 1 unplanned reoperation (P=0.031). Binary logistic multivariate regression accounting for age and scoliosis etiology demonstrated that patients aged 0 to 2 had a significantly greater odds of undergoing an unplanned reoperation (odds ratio=3.050; 95% confidence interval: 1.285-7.241; P=0.011) compared with patients aged 3 to 10 years. CONCLUSION: Overall, EOS patients aged 0 to 2 at initial VEPTR implantation are up to 3 times higher risk of undergoing an unplanned reoperation compared with those aged 3 to 10. LEVEL OF EVIDENCE: Level III.

Posterior thoracolumbar hemivertebra resection and short-segment fusion in congenital scoliosis: surgical outcomes and complications with more than 5-year follow-up.

BACKGROUND: Treatment of congenital hemivertebra is challenging and data on long-term follow-up (≥ 5 years) are lacking. This study evaluated the surgical outcomes of posterior thoracolumbar hemivertebra resection and short-segment fusion with pedicle screw fixation for treatment of congenital scoliosis with over 5-year follow-up. METHODS: This study evaluated 27 consecutive patients with congenital scoliosis who underwent posterior thoracolumbar hemivertebra resection and short-segment fusion from January 2007 to January 2015. Segmental scoliosis, total main scoliosis, compensatory cranial curve, compensatory caudal curve, trunk shift, shoulder balance, segmental kyphosis, and sagittal balance were measured on radiographs. Radiographic outcomes and all intraoperative and postoperative complications were recorded. RESULTS: The segmental main curve was 40.35° preoperatively, 11.94° postoperatively, and 13.24° at final follow-up, with an average correction of 65.9%. The total main curve was 43.39° preoperatively, 14.13° postoperatively, and 16.06° at final follow-up, with an average correction of 60.2%. The caudal and cranial compensatory curves were corrected from 15.78° and 13.21° to 3.57° and 6.83° postoperatively and 4.38° and 7.65° at final follow-up, with an average correction of 69.2% and 30.3%, respectively. The segmental kyphosis was corrected from 34.30° to 15.88° postoperatively and 15.12° at final follow-up, with an average correction of 61.9%. A significant correction (p < 0.001) in segmental scoliosis, total main curve, caudal compensatory curves and segmental kyphosis was observed from preoperative to the final follow-up. The correction in the compensatory cranial curve was significant between preoperative and postoperative and 2-year follow-up (p < 0.001), but a statistically significant difference was not observed between the preoperative and final follow-up (p > 0.001). There were two implant migrations, two postoperative curve progressions, five cases of proximal junctional kyphosis, and four cases of adding-on phenomena. CONCLUSION: Posterior thoracolumbar hemivertebra resection after short-segment fusion with pedicle screw fixation in congenital scoliosis is a safe and effective method for treatment and can achieve rigid fixation and deformity correction.