Convex Side Research Articles

Life-threatening postoperative hemorrhage caused by lumbar artery injury in asymmetrical pedicle subtraction osteotomy for severe spinal deformity: two case reports.

To present two cases of life-threatening hemorrhage related to lumbar artery injury in adult spinal deformity (ASD) patients following S2‑alar‑iliac (S2AI) fixation and asymmetrical pedicle subtraction osteotomy (PSO), and discuss the possible reasons for postoperative hemorrhage in these patients. Patient A was a 52-year-old female with degenerative lumbar scoliosis who underwent posterior spinal fusion from T8-S2 and one-level PSO at L2. Patient B was a 24-year-old male with severe kyphoscoliosis due to non-ambulatory cerebral palsy, who underwent posterior spinal fusion from T3-S2 and one-level PSO at L1. Both patients underwent asymmetric PSO, where a larger wedge was resected from the convex side of the vertebral body rather than the concave side. Both patients occurred a sudden increase in drainage within 3h postoperatively, who were under anesthesia in AICU. Digital subtraction angiography (DSA) was emergently performed and revealed that the bleeding sites were from the lumbar artery, which was adherent to the convex side of the osteotomized vertebra in both cases. Then successful bleeding control was achieved through vascular embolization. Postoperative CT revealed spike formation at the anterior edges of the open wedge at the PSO level due to sagittal translation (ST), with noticeable derotation of the osteotomized vertebra. For patients with severe kyphoscoliosis, asymmetrical PSO increases the risk of lumbar artery injury on the convex side, and postoperative ST may further contribute to this risk. In cases where a sudden increase in drainage is observed postoperatively, it is crucial to consider the possibility of lumbar artery injury, particularly on the convex side of the osteotomized vertebra.

Reducing the Brace Correction Stress on the Secondary Lumbar Curve Results in Excellent Muscle, Bone, and Disc Mechanical Performance: A Musculoskeletal Finite Element Simulation of AIS Patient With Rigo A3.

The biomechanical mechanism of brace intervention on bone, muscle, and disc should be comprehensively considered for AIS patients. We aimed to developmentally construct a musculoskeletal finite element model of adolescent idiopathic scoliosis to simulate the coupling of corrective forces and analyze the mechanical properties of bone, muscle, and disc. Investigateing, more effective clinical interventions to break the vicious cycle of patients during growth. A finite element model, including muscle, bone, and disc, was established using computed tomography data of a patient with RigoA3 adolescent idiopathic scoliosis. The three-point force coupling, antigravity, and bending effects of the Chêneau brace were simulated, and the correction force of the secondary lumbar bend was gradually reduced while observing the mechanical characteristics of bone, muscle, and disc. The correction force in line with symmetrical spine growth was comprehensively evaluated. The correction rate of the main thoracic (MT) curve, the intervertebral space height on the concave side of the vertebrae at the apex, and the stress ratio of the intervertebral discs were optimal when the maximum corrective pressure threshold was reached. However, the proximal thoracic (PT) curve was aggravated and the axial forces on the concave side were unbalanced. At this time, the biomechanical performance of the model is also not optimal. The correction rate of the Cobb Angle of the MT curve decreased with the decrease of the correction pressure in the lumbar region. When reduced to 25% of the maximum threshold, the convex side of disc stress, intervertebral space, and muscle axial force is more in line with the biomechanical mechanism of correction and can avoid sacrificing the PT curve. Downward adjustment of the corrective force to the secondary lumbar curve, using the Chêneau brace, results in better primary thoracic curvature mechanics in the musculoskeletal finite element model, suggesting that breaking the vicious cycle of scoliosis progression to guide benign spinal growth is beneficial.

Zones where reduced implant density leads to correction loss after scoliosis surgery for Lenke 1A adolescent idiopathic scoliosis: a multicenter study.

Investigate zones where implant density should not be reduced in posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) Lenke type 1A curves. 126 consecutive patients (118 female and 8 male; mean age: 15.1 ± 2.2years) with Lenke type 1A AIS who underwent PSF using pedicle screw constructs were included. Correction loss which was calculated using immediately postoperative and 2-year postoperative Cobb angle. Implant density was assessed by dividing the instrumented levels into four zones each on the concave and convex sides. The risk factors for significant correction loss were examined using logistic regression analysis. For convex apical zone, correction loss was compared among the three groups of low (0-59%), medium (60-99%), and high (100%) implant density. Multivariate analysis revealed the apical zone of the convex side (Odds ratio [OR] 1.27; 95% confidence interval [CI] 1.01-1.59; P = 0.04) and the peri-apical zone of the convex side (OR 1.33; 95% CI 1.11-1.59; P = 0.002) as independent predictors of significant correction loss. In the convex apical zone, the median (interquartile range) correction loss of the low implant density, medium implant density, and high implant-density groups was 4.8° (1.5°), 5.3° (0.8°), and 2.2° (0.3°), respectively. The median difference was 2.6° (P = 0.048) between the low implant density and high implant-density group and 3.1° (P < 0.001) between the medium implant density and high implant-density group. In PSF for AIS Lenke 1A, low implant density in the convex apical zones were significant factors affecting correction loss at 2years postoperatively. However, the difference in correction loss between groups may not be large enough to consider clinically meaningful. Prospective studies of longer term outcomes are needed to determine whether these results are clinically important.

Realizing Arbitrary 3D Microarchitectures with Curved and near-Sharp Segments via Toolpath Strategies in Aerosol Jet Printing

Aerosol Jet (AJ) printing is a jetting-based additive manufacturing (AM) technique that uses droplets in an aerosol form to deposit nanoparticles or polymer inks at a length scale of about 10 micrometers. The desired structural geometries via AJ printing can be obtained at a high efficiency and accuracy by engineered toolpaths and fill strategies. Recently, AJ printing is used to create three-dimensional (3D) freestanding microarchitectures such as microlattices, spirals, walls, and micropillars without any auxiliary support during printing. In this work, we demonstrate that for curved segments, the difference in the printed material volume on the convex side vs concave side leads to the accumulation of material while building freestanding 3D microarchitectures. This effect is most severe for sharp corners, which leads to build-defects such as protrusions and voids. We carry out a systematic study of the material accumulation on curved segments of AJ printed 3D microarchitectures. For 3D microwall segments with sharp curved portions, a positive (or negative) material accumulation causing large overgrowths (or voids) as a function of the angle between the tangents on the two sides of the microwalls and the radii of curvature are studied. For sharp bends (<15°) in the microwalls, adding a radius of curvature may not be sufficient to avoid overgrowths and voids, and the lines can be considered as individual segments. For microwall bends with >45°, smaller radii of curvature can be tolerated. We conclude that a fillet radius equal to the line width for 30° angles is necessary to avoid accumulation and therefore the protrusion defects. A simple model based on mass-conservation is also developed which shows the importance of considering ink self-leveling during printing. This information is then used for toolpath strategies to avoid defects on sharp curved microwall segments for complex 3D architectures such as protruding star shape and Scotty Dog, the Carnegie Mellon University mascot. This research will enable the defect-free fabrication of highly complex 3D microarchitectures via jetting-based AM techniques such as AJ printing.

Numerical Study on the Effect of Installing Circular Cylinders in Front of the Returning Blade and Beside the Advancing Blade of the Savonius Wind Turbine

Previous research has proven that placing a disruptive cylinder in front of the Savonius wind turbine’s returning blade can significantly increase the performance of the Savonius turbine. In this study, two-dimensional unsteady simulations with a quadratic pave-type structured mesh showed that the circular cylinder placed in front of the returning blade and next to the advancing blade provides the best performance results at a free flow speed of 5 m/s and a Reynolds number of 100,000. In this study, the comparison with experimental data from another study is utilized. The Savonius turbine is installed with an interfering cylinder in front of the returning blade and next to the advancing blade; the air is tighter on the concave side of the advancing blade. The coefficient pressure difference between the convex and concave sides of the blade increases. The maximum moment is achieved in the turbine with a disturbance cylinder at a configuration distance of S/D 1.4 – Y/D 1.61. The maximum moment coefficient is obtained at the position θ = 15°. The placement of two cylinders with a ratio variation of 0.5 D can significantly influence turbine performance. Results show the turbine provides the highest Power Coefficient when TSR = 0.6. The power coefficient increased by 25.11% compared with that of conventional Savonius turbines. Therefore, it can be concluded that the turbine is the optimal configuration for generating the highest power.

Spinal muscle characteristics during three different types of locomotion activities among college students with idiopathic scoliosis

Background contextPhysical activities such as walking and climbing stairs are pervasive in human daily life. Individuals with scoliosis frequently encounter dysfunction in their muscle recruitment. Multiple studies have corroborated the presence of muscle dysfunction in individuals diagnosed with scoliosis. However, there is currently a noteworthy research gap regarding the exploration of changes in muscle characteristics and disparities from those observed in individuals without scoliosis during everyday activities, specifically stair climbing.PurposeThis study aims to examine the unique patterns of muscle activity during daily life in individuals with scoliosis and distinguish the specific differences between scoliosis patients and the healthy controls. The findings of this study are significantly important for the future accurate assessment of scoliosis and the development of rehabilitation treatment plans.Study designCase–control study.Sample sizeTwenty eight idiopathic scoliosis patients and twenty eight controls.Outcome measuresRoot Mean Square(RMS), Maximum Voluntary Isometric Contraction(MVIC)%, RMS ratio(RMS convex / RMS concave).MethodsThe surface electromyography (sEMG) device used in this study was the Delsys Trigno, with a sampling frequency of 1500 Hz. It recorded the activation level, peak contraction, and average activation level of the erector spinae (at T6, T10, and L3 levels), gluteus maximus, gluteus medius, external oblique, and rectus abdominis muscles during three different types of locomotion for both the 28 individuals with idiopathic scoliosis and the 28 control participants.ResultsThe movement patterns of the idiopathic scoliosis patients significantly differ from those of the normal population during level walking and ascending or descending stairs. In level walking, there is an asymmetry in the activation levels of the T6 and L3 erector spinae muscles, with lower activation on the convex side compared to the concave side. Similarly, during stair ascent, the activation of the T6 and T10 erector spinae muscles is asymmetric, with higher activation on the convex side than the concave side. Moreover, during stair descent, the activation of the T6 erector spinae muscle is asymmetric, with higher activation on the convex side than the concave side.ConclusionsDuring level walking and stair activities, idiopathic scoliosis patients exhibit pronounced abnormal movement patterns that significantly differ from those of the control group. Under different activity conditions such as level walking, ascending and descending stairs, idiopathic scoliosis patients demonstrate abnormal muscle activation in different segments of the spine. It is crucial for clinicians to prioritize the symmetry of muscle activation in the spinal region of idiopathic scoliosis patients and consider incorporating symmetry training for these muscles.

Biomechanical Analysis and Modeling of Different Traction Patterns in Adolescent Idiopathic Scoliosis

Objective: Traction is a valuable treatment for Adolescent idiopathic scoliosis; however, assessing its biomechanical effects, particularly with new methods, presents challenges. This study aims to explore the biomechanics using finite element analysis, with the goal of enhancing safety and effectiveness. Methods: Based on CT images, two different boundary and loads were applied to simulate two traction methods. The effects of these two traction methods on stress and deformation of lumbar vertebral bodies and intervertebral discs were compared. Results: Under two traction methods, the stress was concentrated on the posterior side. Multi-point traction resulted in higher stress and deformation, and concentrated stress on the convex side as well. However, there is some stress concentration on the vertebral arch, which may lead to injury. Conclusion: Compared to longitudinal traction, multi-point traction can better reduce stress on the vertebral bodies and intervertebral discs, focusing the pulling force on the concave side and achieving greater deformation. Multi-point traction might better suit specific patients needing more correction and pressure relief compared to longitudinal traction.

A novel classification of congenital cervicothoracic scoliosis: identification of coronal subtypes and their prognostic significance.

To propose a novel classification system for stratifying coronal curve patterns in congenital cervicothoracic scoliosis with hemivertebrae (CTS-HV). Type A: regional cervicothoracic deformity only disturbing the balance of head-neck-shoulder complex; Type B: cervicothoracic deformity with significant trunk tilt to the convex side; Type C: cervicothoracic deformity with a significant compensatory thoracic curve. The reliability and reproducibility were assessed via the Kappa test. The differences among different subtypes in deformity parameters and bony structures were compared to identify the causative factors predisposing to different subtypes. 98 patients were classified into Type A (47 cases), Type B (31 cases), and Type C (20 cases). The Kappa test showed excellent reliability (Kappa value = 0.847) and reproducibility (Kappa value = 0.881). The proportions of Klippel-Feil syndrome in Types B (71.0%) and C (85.0%) were significantly higher than in Type A (46.8%; all P < 0.05). Type A (66.0%) and Type B (71.0%) predominantly had their hemivertebra (HV) at T3 or T4, while Type C (75%) mostly had HV at T1 or T2. Type B exhibited the most severe trunk tilt, head shift, neck tilt, head tilt, and coronal balance distance (all P < 0.05). Type C had the lowest T1 tilt and first rib angle despite the greatest cervicothoracic Cobb angle (all P < 0.05). This novel reliable classification allows a better understanding of structural diversity and different coronal compensatory mechanisms for the natural progression of CTS-HV. It can contribute to determining the individualized treatment strategy and standardizing academic communication for this rare clinical entity.

Vertebral Body Morphology in Neuromuscular Scoliosis with Spastic Quadriplegic Cerebral Palsy

Background/Objectives: The distorted vertebral body has been studied in scoliosis; however, there is little knowledge about the difference between neuromuscular and idiopathic scoliosis. This study aimed to investigate the vertebral body morphology in patients with spastic quadriplegic cerebral palsy and scoliosis (CP scoliosis) and compare them with those of apex- and Cobb angle-matched patients with adolescent idiopathic scoliosis (AIS). Methods: Thirty-four patients with CP scoliosis and thirty-two patients with AIS were included. The pedicle diameter, chord length, and vertebral body rotation were evaluated at one level above the apex, one level below the apex, and at the apex using a reconstructed computed tomography scan. The apex of the curve and Cobb angle were too diverse between patients with CP scoliosis or AIS. Eighteen patients were matched in each group according to the apex and Cobb angle (within 5-degree differences) of the major curve, and compared between matched groups (mCPscoliosis vs. mAIS). Results: In the comparison of the apex and Cobb angle-matched groups, there was no statistical difference in the Cobb angle between mCPscoliosis (80.7 ± 13.8 degrees) and mAIS (78.6 ± 13.6 degrees, p = 0.426), and the vertebral body rotation (25.4 ± 15.4° in mCPscoliosis vs. 24.4 ± 6.5° in mAIS, p = 0.594). There was no difference in the pedicle diameters of either the convex (3.6 ± 1.1 mm in mCPscoliosis vs. 3.3 ± 1.2 mm in mAIS, p = 0.24) or concave side (3.1 ± 1.2 mm in mCPscoliosis vs. 2.7 ± 1.6 mm in mAIS, p = 0.127). However, the patients in the mCPscoliosis group were younger (12.7 ± 2.5 years vs. 14.6 ± 2.4 years, p = 0.001), and the chord length was shorter on the convex (38.0 ± 5.0 mm vs. 40.4 ± 4.9 mm, p = 0.025) and concave (37.7 ± 5.2 mm vs. 40.3 ± 4.7 mm, p = 0.014) sides compared with those of the mAIS group. Conclusions: With a similar apex and Cobb angle, the vertebral body rotation and pedicle diameter in patients with CP scoliosis were comparable to those with AIS; however, the chord length was shorter in CP scoliosis. For the selection of the pedicle screw in CP scoliosis, the length of the pedicle screw should be more considered than the diameter.

Influence of septal deviation side on preoperative eustachian tube dysfunction and the effectiveness of septoplasty in alleviating eustachian tube dysfunction.

The Eustachian Tube Dysfunction Questionnaire 7 (ETDQ-7) serves as a valuable tool for assessing eustachian tube dysfunction (ETD). We investigated the impact of septal deviation side on ETD using preoperative ETDQ-7 scores and evaluated the effectiveness of septoplasty based on postoperative ETDQ-7 scores. We conducted a retrospective analysis of patients with septal deviation who were scheduled for septoplasty. ETDQ-7 surveys were conducted preoperative and 1 and 3 months postoperative. 120 patients were included, with 72 completing the ETDQ-7 at all three time points. The average prevalence of ETD was 29.2%. Preoperative ETDQ-7 scores showed no significant difference between convex and concave nasal sides. However, the prevalence of ETD was significantly higher on the convex side (28.3% vs. 15.8%), especially in unilateral ETD cases. Preoperatively, the positive ETD group had significantly higher ETDQ-7 scores on the convex side while no significant difference was found between concave and convex sides in the negative ETD group. Postoperatively, the positive ETD group showed significant improvement in ETDQ-7 scores with significantly higher on the convex side (66.7% vs. 33.3%). ETDQ-7 scores improved after septoplasty, with more improvement in the positive ETD group. Septoplasty significantly improves ETD, particularly in the preoperative positive ETD group, by reducing ETDQ-7 scores. The prevalence of ETD was higher on the convex side preoperatively, and the positive ETD group exhibited significant postoperative improvements, especially on the convex side. This suggests that the direction of septal deviation influences ETD prevalence and surgery outcomes, although septoplasty alleviates ETD on both sides.

Analysis of vertebrotomy treatment in children with congenital scoliosis with unsegmented rod and rib synostosis

BACKGROUND: Congenital anomalies of vertebral development account for 2%–11% of cases in the general structure of nosologies that cause spinal deformity. An unsegmented rod (unilateral violation of vertebral segmentation) is attributed to a prognostically unfavorable malformation. Rib synostosis causes the development of thoracic insufficiency syndrome. AIM: To analyze the results of treatment of children with congenital scoliosis caused by an unsegmented rod and rib synostosis by vertebrotomy. MATERIALS AND METHODS: This cohort, retrospective, monocenter study evaluated the treatment results of 55 patients. The patients were divided into two groups: group 1, children aged 2–8 years, the scope of intervention was wedge-shaped osteotomy of a non-segmented rod at the apex of the deformity, and group 2, children aged 8–18 years, the scope of intervention was wedge-shaped osteotomy at the apex of the deformity and two linear osteotomies of a non-segmented rod in the cranial and caudal directions. Clinical, radiological, and statistical research methods were used. RESULTS: Significant correction of scoliosis was achieved in 65.5% of patients aged 2–7 years (group 1) and 56.3% in children aged 8–18 years (group 2). Hypokyphosis of the thoracic spine was observed in the patients. The percentage of correction of kyphosis was 21.1% in group 1 and 19.1% in group 2. Lung volume increased by 27.9% (p = 0.01776) in group 1, and lung volume on the concave side increased by 23.5% (p = 0.04975) and on the convex side by 29.6% (p = 0.01073). Improvement in the overall respiratory impedance reached 47.3% (p 0.05). In group 2, a insignificant increase was found in VVC by 12.6% (p = 0.3509) and FEV1 by 8.7% of the initial (p = 0.1534), as well as an increase in total lung volume of 13.3% (p = 0.1527) and the contribution of the lung along the concave side of 18.8% (p = 0.1535), and the lung along the convex side was 8.4% (p = 0.169), indicating no significant impact on lung development and function. CONCLUSIONS: In children with spinal deformity caused by a non-segmented rod with normal respiratory function, vertebrotomy at the apex of the deformity with subsequent correction and stabilization of the spinal deformity is recommended. Performing simultaneous multilevel osteotomies of a non-segmented rod allows for significant correction of rigid spinal deformity.

Postoperative Coronal Imbalance in Lenke 5C Adolescent Idiopathic Scoliosis: Evolution, Risk Factors, and Clinical Implications.

To explore the changes in coronal imbalance (CIB) in Lenke 5C adolescent idiopathic scoliosis (AIS) after posterior selective fusion surgery and determine their implications for surgical decision-making. One hundred twenty patients were categorized according to the preoperative coronal pattern (type A, coronal balance distance [CBD]<20 mm; type B, CBD≥20 mm and coronal C7 plumbline [C7PL] shifted to the concave side of the curve; type C, CBD≥20 mm and C7PL shifted to the convex side of the curve). CIB group (CIB+) was defined as having a CBD≥20 mm at the 2-year follow-up. Compared to type A patients, the prevalence of postoperative CIB was higher in type C patients both immediately postoperative (22% vs. 38%, p<0.05) and at the final follow-up (5% vs. 29%, p<0.05), whereas type A patients showed a greater improvement in CBD (9 of 12 vs. 6 of 24, p<0.05) at the final follow-up. The majority of patients in all groups had recovered to type A at the final follow-up (96 of 120). The proximal Cobb-1 strategy reduced the incidence of postoperative CIB (1 of 38) at the 2-year follow-up, especially in preoperative type C patients. Multivariate logistic regression analysis revealed that type C and overcorrection of the thoracolumbar curve were risk factors for CIB at the 2-year follow-up (p=0.007 and p=0.026, respectively). Patients with type C CIB in AIS exhibited unsatisfactory restoration, with 29% of them exhibiting CIB at the final follow-up. The selective fusion strategy of proximal Cobb-1 may reduce the risk of postoperative CIB especially when the preoperative coronal pattern is type C.

Controlling the Apex in Early Onset Scoliosis Through Active Apex Correction (APC) Non Fusion Growth Modulating Technique, Is It a Myth?

A multicenter retrospective study. To determine the rate of Apex facet fusion in children with Early Onset Scoliosis treated surgically with the Active Apex Correction (APC) technique. Seventeen patients were treated with the APC technique as index surgery for Early Onset Scoliosis with more than 1year of follow-up. A 3D CT scan was done to determine the facet fusion rate in the deformity's apex controlled with posterior tethering. The average follow-up time was 26.4months (12-56), Average age at index surgery was 81.2months (30-132), and average number of surgeries done 1.3. Apical vertebrae studied for facet fusion were the 3 vertebrae in the apex in each patient that were subjected to posterior tethering according to the APC technique. In total they were 86 apical vertebrae (172 Facets studied with 86 convex side, 86 concave side). Our observations showed that 29 facet joints were fused (16% of the total facets studied),15 were on the convex, 14 on the concave side (no statistically significant difference). Regarding the facet joint distance in the non-fused facets was 0.99mm on the convex side and 1.08mm on the concave side with no statistical significance difference. APC for Early Onset Scoliosis achieves apical growth modulation and control utilizing posterior tethering without inducing fusion. This study demonstrated that APC is an effective non-fusion technique through the low incidence of facet fusion levels at the Apex, limiting the crankshaft phenomena seen in cases with apex control through arthrodesis.

Outdoor Performance Analysis of Semitransparent Photovoltaic Windows with Bifacial Cells and Integrated Blinds

The stricter requirements for the energy performance of buildings are creating a market for several building‐integrated photovoltaic (BIPV) technologies, including photovoltaic (PV) windows. Herein, an innovative multifunctional PV window concept designed to enhance energy generation while providing overheating protection for better indoor thermal and visual comfort is presented. This concept utilizes bifacial c‐Si solar cell strips combined with venetian blinds, all embedded in a unique insulating glazing unit. The bifacial technology increases the energy yield by using the blinds as reflectors, directing more irradiance to the cells’ rear side. The goal of this study is to analyze the outdoor performance of this concept under real operating conditions. Twelve demonstrators are installed and monitored. Various measurement campaigns are conducted, examining the impact of different blind types, tilt angles, sun positions and sky conditions. The highest energy boosts occur when the blinds are fully closed at a 75° angle with their convex side facing outward. Blinds with the highest specular reflectance achieve a maximum performance increase of 25% on sunny days and a daily average increase of 12% compared to the case of no blinds.

The influence of the axial group on the crystal structures of boron subphthalocyanines.

The crystal structures of 16 boron subphthalocyanines (BsubPcs) with structurally diverse axial groups were analyzed and compared to elucidate the impact of the axial group on the intermolecular π-π interactions, axial-group interactions, axial bond length and BsubPc bowl depth. π-π interactions between the isoindole units of adjacent BsubPc molecules most often involve concave-concave packing, whereas axial-group interactions with adjacent BsubPc molecules tend to favour the convex side of the BsubPc bowl. Furthermore, axial groups that contain O and/or F atoms tend to have significant hydrogen-bonding interactions, while axial groups containing arene site(s) can participate in π-π interactions with the BsubPc bowl, both of which can strongly influence the crystal packing. Bulky axial groups did tend to disrupt the π-π interactions and/or axial-group interactions, preventing some of the close packing that is seen in BsubPcs with less bulky axial groups. The atomic radius of the heteroatom bonded to boron directly influences the axial bond length, whereas the axial group has minimal impact on the BsubPc bowl depth. Finally, the crystal growth method did not generally appear to have a significant impact on the solid-state arrangement, with the exception of water occasionally being incorporated into crystal structures when hygroscopic solvents were used. These insights can help with the design and fine-tuning of the solid-state structures of BsubPcs as they continue to be developed as functional materials in organic electronics.

Evaluation of Paravertebral Muscle Structure Asymmetry in Idiopathic Scoliosis Using Imaging Techniques

ObjectiveThis study aimed to assess variances in paravertebral muscle structure in individuals with idiopathic scoliosis（IS） through imaging techniques. MethodsA cohort of 112 patients diagnosed with IS and treated at our institution between January and December 2023 were included in the analysis. During the same period, 37 patients with secondary scoliosis（SS）were included as controls. Imaging data were used to measure the Cobb angle of the apical vertebrae in scoliosis patients, along with the area and fat infiltration of the paravertebral muscles on both sides. Finally, the cross-sectional area of the paravertebral muscles and the degree of fat infiltration were comparatively evaluated. ResultsIn patients with IS, the paravertebral muscles on the concave side of the main curve were significantly larger than those on the convex side (P < 0.05). The concave/convex muscle area ratio in IS patients showed a positive correlation with the Cobb angle and scoliosis duration (both P < 0.05). There was no significant difference in the muscle area ratio between patients with IS and those with SS (P > 0.05). In IS, the paravertebral muscles on the concave side of the main curve exhibited more fat infiltration than those on the convex side, with this fat infiltration positively correlating with body mass index (BMI), Cobb angle, age, and scoliosis duration. Similarly, the degree of fat infiltration in the paravertebral muscles on the concave side of SS was greater than that observed on the convex side. Furthermore, the degree of fat infiltration in the paravertebral muscles associated with SS was more pronounced compared to that seen in IS (P < 0.05). ConclusionIn IS patients, the paravertebral muscles on the concave side are more prominent and exhibit more fat infiltration compared to those on the convex side. This fat infiltration positively correlates with the Cobb angle, scoliosis duration, BMI, and age, possibly indicating scoliosis progression.

Asymmetric Osteopenia in Adolescent Idiopathic Scoliosis Based on Hounsfield Unit of Computed Tomography.

To characterize the asymmetrical loss of bone mass and identify the association between scoliosis and osteopenia in patients with adolescent idiopathic scoliosis (AIS). Demographic information, Cobb angle, and Hounsfield unit (HU) of the neutral vertebra (NV) and apical vertebra (apex) of the major curve were collected retrospectively in 54 AIS patients. For 84 control subjects, HU values were measured at T12 and L5. Propensity score matching was performed to balance the interference of age and BMI. In the AIS group, the concave and convex lateral HU of the NV and the convex lateral HU of the apex were negatively correlated with the Cobb angle. The AIS patients had lower bilateral HU. The mean HU and the apex-convex HU were also lower in the AIS group, while the apex-concave HU was slightly higher. After matching, the apex-convex HU of the AIS group remained lower, while the apex-concave HU was higher. Patients with AIS exhibit osteopenia, particularly on the convex side. The severity of scoliosis was found to be directly proportional to the severity of bone loss and the degree of bilateral osteopenia asymmetry. Appropriate intervention for bone loss may be able to curb the progression of scoliosis.

A Combined Investigation of Bending Behavior of a SiC Fiber‐Reinforced Titanium Matrix Composite with Compressive and Tensile Tests

The study investigates the bending behavior and failure mechanisms of a titanium matrix composite reinforced with SiC fibers. The effects of nominal fiber volume fraction, testing temperature, and fiber position on bending behavior are evaluated. The results indicate that increasing the nominal fiber volume fraction from 19% to 50% improves average bending strength, reaching 2757 MPa at room temperature and 2596 MPa at 350 °C. Fiber position significantly influences bend strength, and composites with fibers on the concave side show greater strength than those with fibers on the convex side. Cracks in the composite specimen preferentially initiate from the bottom of the composite core rather than from the top, and fiber breakage under tensile stress is the dominant damage mechanism in the bend test. That is consistent with the lower tensile strength relative to the compressive strength of the composite.

Posterior-only approach cervical hemivertebrectomy and short fusion with pedicle screws in young children with cervical scoliosis: case report and technical note.

Cervical hemivertebrae (C3-6) causing significant osseous torticollis, head tilt and facial asymmetry are rare and complicated. Cervical hemivertebrectomy (CHVE) by a posterior-only approach was never reported because it is highly risky and its efficacy remains controversial. This study is to evaluate the feasibility and preliminary clinical outcomes of posterior-only approach for CHVE and torticollis correction in young children. Four young children aged 5-9 years old with significant torticollis caused by cervical hemivertebrae underwent deformity correction consisting of cervical pedicle screw (CPS) placement with O-arm-based intraoperative navigation, CHVE using ultrasonic bone scalpel and short-segmental posterior instrumentation and fusion. Details of this novel technique were presented. The preliminary short-term clinical and radiographic outcomes were assessed. On average, the operative time was 312.5 ± 49.9min, and the surgical blood loss was 375.0 ± 150.0ml. The structural cervical scoliosis was corrected from 31.5 ± 7.3° to 11.0 ± 4.1°, and the average correction rate was 64.9%. Head tilt was favorably corrected from 11.0 ± 4.2° to 3.5 ± 2.6°. The shoulder balance improved from 6.3 ± 1.3° to 1.5 ± 1.9°. One case with C6 CHVE had convex side radiating nerve root pain but no sign of muscle power weakness. Full recovery was achieved one month after surgery. No other complication occurred. CHVE by a posterior-only approach was a feasible alternative option for the treatment of congenital cervical scoliosis. It could resect the CHV effectively and achieve satisfactory torticollis correction without additional anterior access surgery. Successful CPS placement in this child population was essentially important to enable reliable osteotomy closure and firm posterior instrumentation.

Characteristic of Paraspinal Muscle Change in Coronal Sub-type of Degenerative Lumbar Scoliosis and its Potential Clinical Significance.

Clarifying paraspinal muscle (PM) change in degenerative lumbar scoliosis (DLS) is positive to evaluate the progression of scoliosis. This research compares the characteristic of PM change among different coronal sub-types of DLS and explores its potential clinical significance. A total of 84 DLS patients between June 2019 to December 2021 were retrospectively analyzed. Patients were classified into three types based on the coronal balance distance (CBD): Type A, CBD <3 cm; Type B: C7 Plumb Line (C7PL) shifted to the concave side of the curve, and CBD >3 cm; Type C: C7PL shifted to the convex side of the curve, and CBD >3 cm. Fat infiltration rates in the multifidus (MS) and erector spinae (ES) at the apex of the main and fractional curves, and spinopelvic parameters were analyzed statistically. Pearson's or Spearman's correlation was applied to analyze the correlation between asymmetric degree of PM change and these parameters in three types. There were 62 cases with coronal sub-Type A, 6 cases with Type B, and 16 cases with Type C. Patients in Type B and C demonstrated higher fat infiltration in MS on the concave side of both the main and fractional curves when compared to those in Type A. The asymmetric degree of ES change was positively correlated with CBD at the apex of the main curve in Type B and at the apex of the fractional curve in Type C respectively, and that of MS was positively correlated with apical vertebral rotation, while negatively strong-correlated with pelvic incidence and sacral slope in Type C. PM fatty infiltration presented difference among varied coronal sub-types of DLS patients. The CBD in Type B and C patients was correlated with the asymmetric degree of ES change.