Morphological differences in adolescent idiopathic scoliosis: a histological and ultrastructural investigation

Research progress on the regulation of bone marrow stem cells by noncoding RNAs in adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a common spinal deformity in young women, but its pathogenesis remains unclear. The primary pathogenic factors contributing to its development include genetics, abnormal bone metabolism, and endocrine factors. Bone marrow stem cells (BMSCs) play a crucial role in the pathogenesis of AIS by regulating its occurrence and progression. Noncoding RNAs (ncRNAs) are also involved in the pathogenesis of AIS, and their role in regulating BMSCs in patients with AIS requires further evaluation. In this review, we discuss the relevant literature regarding the osteogenic, chondrogenic, and lipogenic differentiation of BMSCs. The corresponding mechanisms of ncRNA-mediated BMSC regulation in patients with AIS, recent advancements in AIS and ncRNA research, and the importance of ncRNA translation profiling and multiomics are highlighted.

Smaller Intervertebral Disc Volume and More Disc Degeneration after Spinal Distraction in Scoliotic Children

In recent decades, magnetically controlled growing rods (MCGR) were established to treat progressive early-onset scoliosis. The aim of this investigation was to assess the effect of long-term MCGR with continuous distraction on intervertebral discs in scoliotic children. Magnetic resonance imaging (MRI) of 33 children with spinal muscular atrophy was analyzed by grading intervertebral disc degeneration (IDD) and measuring intervertebral disc volume. Cohort I (n = 17) were children who had continuous spinal distraction with MCGRs for 5.1 years and MRI before (av. age 8.1) and after (av. age 13.4) MCGR treatment. Cohort II (n = 16, av. age 13.7) were patients without prior surgical treatment. Lumbar intervertebral disc volume of cohort I did not change during 5.1 years of MCGR treatment, whereas disc volumes were significantly larger in age- and disease-matched children without prior treatment (cohort II). Cohort I showed more IDD after MCGR treatment in comparison to early MRI studies of the same patients and children without surgical treatment. MRI data showed a volume reduction and disc degeneration of lower thoracic and lumbar intervertebral discs in scoliotic children after continuous spinal distraction with MCGRs. These effects were confirmed in the same subjects before and after treatment as well as in surgically untreated controls.

Residual lumbar curvature that developed during adolescence accelerates intervertebral disc degeneration in adulthood

PURPOSE

To elucidate the influence of spinal deformity in adolescent idiopathic scoliosis (AIS) on lumbar intervertebral disc (IVD) degeneration in adulthood using magnetic resonance imaging (MRI).

METHODS

A total of 102 patients (8 men, 94 women; mean age, 31.4 years) who had developed idiopathic scoliosis at the age of 10-18 years and underwent preoperative lumbar spine MRI at the age of ≥ 20 were included in the study. Twenty volunteers (3 men, 17 women; mean age, 33.6 years) without scoliosis were assessed as controls. We divided the adult scoliosis patients into two groups: Group A consisted of patients with lumbar modifier A, and Group BC consisted of those with modifiers B and C. IVD degeneration from L1/2 to L5/S1 was assessed by MRI. The Scoliosis Research Society-22 (SRS-22) patient questionnaire was used in the patients' clinical assessment.

RESULTS

There were 40 patients in the Group A and 62 in the Group BC. Compared to the control groups, significant IVD degeneration was observed at L2/3 and L3/4 in Group A, and at all levels except for L5/S1 in Group BC. The proportion of degenerated IVDs patients (Grades 1c and 2) was significantly higher in Group BC than those in Group A at L3/L4 and L4/L5. Furthermore, the severity of IVD degeneration was significantly greater in the group BC than in the group A at all levels, except for L5/S1, especially in patients aged > 30 years. The mean scores of all subdomains in the SRS-22 questionnaire were comparable between the two groups.

CONCLUSION

Our study showed that the residual lumbar curvature from AIS may have accelerated IVD degeneration in adulthood, especially in patients aged > 30 years.

LEVEL OF EVIDENCE

III.

Accurate prediction of spontaneous lumbar curve correction following posterior selective thoracic fusion in adolescent idiopathic scoliosis using logistic regression models and clinical rationale

INTRODUCTION

Accurate prediction of spontaneous lumbar curve correction (SLCC) after selective thoracic fusion (STF) remains difficult. This study sought to improve prediction accuracy of SLCC. The hypothesis was preoperative and intraoperative variables could predict SLCC < 20°.

METHODS

A multicenter observational prospective analysis was conducted to determine predictors of SLCC in AIS patients that had posterior STF. Curve types included major thoracic curves (Lenke 1, 3-4).The primary outcome variable was to establish prediction models, and a postoperative lumbar curve (LC) ≤ 20° was defined as the target variable. Multivariate logistic regression models were established to study the relationship between selected variables and a LC ≤ 20° versus a LC > 20° at ≥ 2-year follow-up. Single and dual thresholds models in perspective of clinical rationales were applied to find models with the highest positive/negative predictive values (PPV/NPV). The secondary outcome measure was SRS scores at ≥ 2-year follow-up.

RESULTS

410 patients were included. At ≥ 2-year follow-up 282 patients had LC ≤ 20°. These patients had better SRS-22 scores than those with LC > 20° (P = 0.02). The postoperative LC and LC ≤ 20° were predicted by preoperative LC and LC-bending Cobb angle (P < 0.01, r = 0.4-0.6). Logistic regression models could be established to identify patients at risk for failing the target LC ≤ 20°.For preoperative LC and LC-bending, the prediction model achieved a NPV/PPV of 80%/72%. If the postoperative main thoracic curve is combined with the preoperative LC and a gray area for difficult decisions was allowed, model accuracy could even be improved (NPV/PPV = 96%/81%).

CONCLUSION

An accurate prediction model for postoperative SLCC was established based on a large analysis of prospective STF cases. These models can support prediction and understanding of postoperative SLCC aiding in surgical decision making when contemplating a selective thoracic fusion. These slides can be retrieved under Electronic Supplementary Material.

Tracking low back pain in adolescent idiopathic scoliosis: a prospective cohort study protocol

Background

Numerous methodological limitations have constrained the findings of previous studies that have examined the prevalence of low back pain in adolescents with idiopathic scoliosis. This article presents a study protocol that has been designed to address the shortcomings of prior research in this area. In addition, it will establish the level of disease burden associated with acute, recurrent, and chronic low back pain in adolescents with idiopathic scoliosis.

Methods

This study will involve a prospective cohort of adolescents with idiopathic scoliosis presenting to an outpatient department in a paediatric hospital. Potential participants will be eligible for inclusion if they are aged 10–17 years, experience adolescent idiopathic scoliosis, own a mobile phone, and are able to communicate in either French or English adequately. The primary outcome measure is the presence of low back pain. The secondary outcome will be measures with the Brief Pain Questionnaire and the PedsQL questionnaire. Participants will be followed over a 12-month period reporting weekly, via SMS-tracking.

Discussion

Previous studies frequently established the prevalence of low back pain through asking participants to recall whether they experienced low back pain over certain periods. These periods often extended beyond many months, and hence were subject to recall bias. Our study addresses such bias through gathering data on a weekly basis using SMS-tracking providing detailed information about the progression of low back pain, which allows researchers to establish the prevalence of acute, recurrent, and chronic low back pain with a better certainty. Furthermore, the previous studies failed to use a standardised definition of low back pain. As such, it is not possible to determine whether the reported low back pain was experienced at the following standardised defined location: “pain in the space between the lower posterior margin of the rib cage and the horizontal gluteal fold”.

Conclusion

This research protocol will be the first study to determine the proportion of adolescents with idiopathic scoliosis who experience acute, recurrent, and chronic low back pain, and establish the level of the burden associated with these subgroups of low back pain.

Morphological changes in the human cervical intervertebral disc post trauma: response to fracture-type and degeneration grade over time

PURPOSE

In the first 24 h post-intervertebral disc (IVD) trauma, up to 75 % cell death has been reported. In addition, burst fractures cause post-traumatic disc degeneration by elevated pro-apoptotic and pro-inflammatory gene transcription. Moreover, some patients have pre-trauma degenerative disc disease. The aim of the study was to assess histological changes and cell-death over a time period of up to 1 year caused by mechanical and structural factors.

METHODS

116 anterior portions of IVDs of the cervical spine were studied histologically by light microscopy and ultrastructurally by transmission electron microscopy (TEM). The group was investigated with regard to three main parameters: fracture mechanism (compressive vs. tensile/shear loads), degeneration grade (low vs. high) and endplate fracture (with vs. without). Disc architecture (e.g. ruptures) was studied histologically. Cell morphology was examined ultrastructurally to quantify cell-death, healthy and balloon cells. According to ultrastructural observations, two time-groups (up to 6 days vs. later) were established. Statistical analyses were carried out within and between time-groups.

RESULTS

Histological changes were obvious in the annulus fibrosus where ruptures with haematoma were replaced by granulation tissue. Significant differences in cell-death were seen in the first few days due to different loads. In contrast to the more degenerated segments, low degenerated ones revealed significantly less cell death with time post-trauma. Interestingly, no difference was found between groups after the sixth day. Cell-death (mean 44 % for all investigated groups) remained high after day 6 post-trauma.

CONCLUSION

IVDs retrieved from low grade degenerated segments revealed a significant recovery, with less cell-death and a partially restored disc matrix, although cell-death remained high. Long-term clinical studies of stabilized segments arising from different fracture mechanisms are required.

Gpr126/Adgrg6 deletion in cartilage models idiopathic scoliosis and pectus excavatum in mice

Adolescent idiopathic scoliosis (AIS) and pectus excavatum (PE) are common pediatric musculoskeletal disorders. Little is known about the tissue of origin for either condition, or about their genetic bases. Common variants near GPR126/ADGRG6 (encoding the adhesion G protein-coupled receptor 126/adhesion G protein-coupled receptor G6, hereafter referred to as GPR126) were recently shown to be associated with AIS in humans. Here, we provide genetic evidence that loss of Gpr126 in osteochondroprogenitor cells alters cartilage biology and spinal column development. Microtomographic and x-ray studies revealed several hallmarks of AIS, including postnatal onset of scoliosis without malformations of vertebral units. The mutants also displayed a dorsal-ward deflection of the sternum akin to human PE. At the cellular level, these defects were accompanied by failure of midline fusion within the developing annulus fibrosis of the intervertebral discs and increased apoptosis of chondrocytes in the ribs and vertebrae. Molecularly, we found that loss of Gpr126 upregulated the expression of Gal3st4, a gene implicated in human PE, encoding Galactose-3-O-sulfotransferase 4. Together, these data uncover Gpr126 as a genetic cause for the pathogenesis of AIS and PE in a mouse model.