Deep Learning-Based Prediction Model for the Cobb Angle in Adolescent Idiopathic Scoliosis Patients.

Scoliosis, characterized by spine deformity, is most common in adolescent idiopathic scoliosis (AIS). Manual Cobb angle measurement limitations underscore the need for automated tools. This study employed a vertebral landmark extraction method and Feedforward Neural Network (FNN) to predict scoliosis progression in 79 AIS patients. The novel intervertebral angles matrix format showcased results. The mean absolute error for the intervertebral angle progression was 1.5 degrees, while the Pearson correlation of the predicted Cobb angles was 0.86. The accuracy in classifying Cobb angles (<15°, 15-25°, 25-35°, 35-45°, >45°) was 0.85, with 0.65 sensitivity and 0.91 specificity. The FNN demonstrated superior accuracy, sensitivity, and specificity, aiding in tailored treatments for potential scoliosis progression. Addressing FNNs' over-fitting issue through strategies like "dropout" or regularization could further enhance their performance. This study presents a promising step towards automated scoliosis diagnosis and prognosis.

Potential Interaction between WNT16 and Vitamin D on Bone Qualities in Adolescent Idiopathic Scoliosis Patients and Healthy Controls.

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that is associated with low bone mineral density (BMD). Vitamin D (Vit-D) supplementation has been suggested to improve BMD in AIS, and its outcomes may be related to genetic factors. The present study aimed to (a) investigate the synergistic effect between a low BMD-related gene (wingless-related integration site 16, WNT16) and two important Vit-D pathway genes (Vit-D receptor, VDR, and Vit-D binding protein, VDBP) on serum Vit-D and bone qualities in Chinese AIS patients and healthy adolescents, and (b) to further investigate the effect of ablating Wnt16 on the cortical bone quality and whether diets with different dosages of Vit-D would further influence bone quality during the rapid growth phase in mice in the absence of Wnt16. A total of 519 girls (318 AIS vs. 201 controls) were recruited, and three selected single-nucleotide polymorphisms (SNPs) (WNT16 rs3801387, VDBP rs2282679, and VDR rs2228570) were genotyped. The serum 25(OH)Vit-D level was significantly associated with VDBP rs2282679 alleles (OR = -4.844; 95% CI, -7.521 to -2.167, p < 0.001). Significant multi-locus models were identified by generalized multifactor dimensionality reduction (GMDR) analyses on the serum 25(OH)Vit-D level (p = 0.006) and trabecular area (p = 0.044). In the gene-edited animal study, Wnt16 global knockout (KO) and wildtype (WT) male mice were provided with different Vit-D diets (control chow (1000 IU/Kg) vs. Vit-D-deficient chow (Nil in Vit-D) vs. high-dose Vit-D chow (20,000 IU/Kg)) from 4 weeks to 10 weeks old. Wnt16 global KO mice had significantly lower serum 25(OH)Vit-D levels and higher liver Vdbp mRNA expression levels than WT mice. In addition, Wnt16 global KO mice showed a decrease in bone density, cortical thickness and cortical area compared with WT mice. Interestingly, high-dose Vit-D chow led to lower bone density, cortical thickness, and cortical area in WT mice, which were less obvious in Wnt16 global KO mice. In conclusion, WNT16 may regulate the serum 25(OH)Vit-D level and bone qualities, which might be associated with VDBP expression. Further investigations with a larger sample size and wider spectrum of scoliosis severity are required to validate our findings regarding the interaction between WNT16 and Vit-D status in patients with AIS.

Phytomolecule icaritin incorporated PLGA/TCP scaffold for steroid-associated osteonecrosis: Proof-of-concept for prevention of hip joint collapse in bipedal emus and mechanistic study in quadrupedal rabbits.

Steroid-associated osteonecrosis (SAON) may lead to joint collapse and subsequent joint replacement. Poly lactic-co-glycolic acid/tricalcium phosphate (P/T) scaffold providing sustained release of icaritin (a metabolite of Epimedium-derived flavonoids) was investigated as a bone defect filler after surgical core-decompression (CD) to prevent femoral head collapse in a bipedal SAON animal model using emu (a large flightless bird). The underlying mechanism on SAON was evaluated using a well-established quadrupedal rabbit model. Fifteen emus were established with SAON, and CD was performed along the femoral neck for the efficacy study. In this CD bone defect, a P/T scaffold with icaritin (P/T/I group) or without icaritin (P/T group) was implanted while no scaffold implantation was used as a control. For the mechanistic study in rabbits, the effects of icaritin and composite scaffolds on bone mesenchymal stem cells (BMSCs) recruitment, osteogenesis, and anti-adipogenesis were evaluated. Our efficacy study showed that P/T/I group had the significantly lowest incidence of femoral head collapse, better preserved cartilage and mechanical properties supported by more new bone formation within the bone tunnel. For the mechanistic study, our in vitro tests suggested that icaritin enhanced the expression of osteogenesis related genes COL1α, osteocalcin, RUNX2, and BMP-2 while inhibited adipogenesis related genes C/EBP-ß, PPAR-γ, and aP2 of rabbit BMSCs. Both P/T and P/T/I scaffolds were demonstrated to recruit BMSCs both in vitro and in vivo but a higher expression of migration related gene VCAM1 was only found in P/T/I group in vitro. In conclusion, both efficacy and mechanistic studies show the potential of a bioactive composite porous P/T scaffold incorporating icaritin to enhance bone defect repair after surgical CD and prevent femoral head collapse in a bipedal SAON emu model.

A review of pinealectomy-induced melatonin-deficient animal models for the study of etiopathogenesis of adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) is a common orthopedic disorder of unknown etiology and pathogenesis. Melatonin and melatonin pathway dysfunction has been widely suspected to play an important role in the pathogenesis. Many different types of animal models have been developed to induce experimental scoliosis mimicking the pathoanatomical features of idiopathic scoliosis in human. The scoliosis deformity was believed to be induced by pinealectomy and mediated through the resulting melatonin-deficiency. However, the lack of upright mechanical spinal loading and inherent rotational instability of the curvature render the similarity of these models to the human counterparts questionable. Different concerns have been raised challenging the scientific validity and limitations of each model. The objectives of this review follow the logical need to re-examine and compare the relevance and appropriateness of each of the animal models that have been used for studying the etiopathogenesis of adolescent idiopathic scoliosis in human in the past 15 to 20 years.

[The thoracic spine morphology under magnetic resonance imaging in adolescent idiopathic scoliosis and its clinical significance].

OBJECTIVES: To evaluate and compare thoracic vertebrae morphology between patients with idiopathic and normal adolescents through MRI. METHODS: Two-dimensional sagittal MRI of the spine was performed in 10 normal adolescent, 10 patients with mild idiopathic thoracic scoliosis (Cobb angle 15 degrees - 39 degrees ) and 10 patients with moderate thoracic scoliosis (Cobb angle 40 degrees - 75 degrees ), all of them were female and between 13 - 14 years old. Sagittal imaging was reconstructed on image working station (Easy Vision, Philips Medical Systems, Best, Netherlands). Anterior height, posterior height and width of vertebral body as well as length between spinous process were measured on each thoracic spine. RESULTS: Anterior height, posterior height and width of vertebral body increased from T(1) to T(12) with the values from scoliotic groups larger than normal group. The anterior height/width ratio and anterior/posterior column ratio were also larger in scoliotic group especially at apical area. CONCLUSION: The thoracic vertebrae are higher and slimmer in scoliotic patient than in normal age-matched girls which implied that there is abnormal endochondral ossification on spine during adolescent growth spurt.

Trabecular bone micro-architecture and bone mineral density in adolescent idiopathic and congenital scoliosis.

OBJECTIVE: To investigate the microstructure of trabecular bone in adolescent idiopathic scoliosis (AIS) and age-matched congenital scoliosis (CS), and to evaluate the bone mineral status of CS patients compared with normal controls and AIS patients. METHODS: This study included 15 AIS and 16 CS female patients and 35 healthy female adolescents. Corrective surgery was indicated for the AIS and CS patients, from whom iliac crest biopsies were collected during autograft harvesting, and scanned by micro-computer tomography. Bone mineral status was assessed at the lumbar and hip areas in every patient by dual energy X-ray absorptiometry (DEXA). RESULTS: Significantly lower lumbar and femoral neck bone mineral density (BMD) was found in AIS patient compared with normal controls. All BMD and bone mineral content (BMC) parameters were significantly lower in CS patients compared with age-matched normal controls. Under DEXA assessment significant associations between bone volume/tissue volume (BV/TV) and BMD values were observed. In the 3D model, BV/TV was significantly higher in AIS (19.9% ± 3.4%) than in CS (13.3% ± 3.0%, P < 0.05). Significant differences between AIS and CS were also found in trabecular thickness (Tb.Th) and bone surface/bone volume (BS/BV) (155.5 ± 54.9 µm vs. 108.1 ± 17.4 µm and 16.4% ± 3.3% vs. 22.0% ± 3.4% respectively, P < 0.05 in both). CONCLUSION: Lower bone mineral status and weak trabecular bone structure observed in AIS and CS justify further investigation of the bone mineral status in scoliosis of various etiologies.

[Effect of genetic polymorphism of MTNR1A gene on adolescent idiopathic scoliosis].

OBJECTIVE: To investigate whether the MTNR1A gene promotor polymorphism (rs2119882) are associated with the occurrence or curve severity of adolescent idiopathic scoliosis (AIS). METHODS: 226 AIS patients and 277 normal controls were recruited. The maximum Cobb angles were recorded in AIS patients. PCR-RFLP was used for the genotyping. RESULTS: The genotype and allele frequency distribution were comparable between AIS and normal control, the mean maximum Cobb angle of different genotypes of rs2119882 were similar with each other among AIS patients. CONCLUSION: The MTNR1A gene promoter polymorphism was neither associated with the occurrence nor the curve severity of AIS.

Virtual reality techniques. Application to anatomic visualization and orthopaedics training.

Surgical training systems using virtual reality simulation techniques offer a cost-effective alternative to traditional training methods. In this sense, techniques for interactive visualization and virtual reality surgery have been one of the very important research areas. We describe various techniques we have used in developing a virtual reality system for anatomic visualization and training arthroscopic knee surgeons. Virtual models used in our systems are constructed from the Visible Human Project and Chinese Visible Human data sets. We present our various developments in segmentation, personal-computer-based real-time volume visualization, soft tissue deformation with topological change in real-time using finite element analysis, and soft tissue cutting with tactile feedback.

[Trabecular bone micro-architecture in adolescent idiopathic scoliosis compared between concave and convex site of the facet joints].

OBJECTIVE: To evaluate the trabecular bone micro-structure from different sites of spine in adolescent idiopathic scoliosis patients. The target site consisted of the bilateral facet joints from apical vertebrae and from end vertebrae. METHODS: Nine AIS patients with mean age 14.9 years (range 12-17 years) and mean Cobb angle 56 degrees (ranged 48 degrees-84 degrees) were recruited into this study. Corrective surgery was indicated to these patients, and facet joint biopsies were collected during decortications for spinal fusion. Biopsy consents were obtained from patients. Bone specimens were fixed with routine histology procedures and scanned by micro computer tomography (muCT40, Scanco Medical, Switzerland). Ten pairs of facet joint were harvested from apical vertebrae and 12 pairs from end vertebrae. Three-dimensional reconstructed images with the resolution of 20 microm were achieved for histomorphometric analysis. RESULTS: The values of BV/TV (0.268 vs. 0.354, P < 0.05), TbTh (0.20 vs. 0.24, P < 0.05), TbSP (0.66 vs. 0.56, P < 0.05) and BS/BV (12.7 vs. 10.4, P < 0.05) between convex and concave side at the apex area were significantly different. No difference was found in any structural parameters between left and right side at end area, and upper thoracic (T5, 6) and thoracolumbar (T12, L1). CONCLUSION: Due to asymmetric compression and tension shared between convex and concave side, more bone and thicker and more profound trabecular bones are observed in the concave side than in the convex side, which seems to resist the progression of spinal curvature. This finding suggests that the provocative factors which cause the progression of the curve in certain patients may not lie in the bone component of spine.

Virtual reality based system for training on knee arthroscopic surgery.

Surgical training systems based on virtual reality (VR) and simulation techniques offer a cost-effective and efficient alternative to traditional training methods. This paper describes a virtual reality system for training arthroscopic knee surgery. The virtual model used in this system is constructed from the Visual Human Project dataset. The system simulates the real-time deformation of soft tissue with topological change using finite element analysis. To offer the realistic tactile feedback, we construct a specialized force feedback hardware.

A virtual-reality training system for knee arthroscopic surgery.

Surgical training systems based on virtual-reality (VR) simulation techniques offer a cost-effective and efficient alternative to traditional training methods. This paper describes a VR system for training arthroscopic knee surgery. Virtual models used in this system are constructed from the Visual Human Project dataset. Our system simulates soft tissue deformation with topological change in real-time using finite-element analysis. To offer realistic tactile feedback, we build a tailor-made force feedback hardware.