Deformation Of Segment Research Articles

Retrospective analysis of restoration of the anatomy of the damaged thoracic and lumbar spinal motion segment using transpedicular repositioning device

Objective. To carry out a retrospective analysis of the restoration of the anterior and posterior vertebral body heights and the elimination of deformation of the anterior spinal canal wall caused by thoracic and lumbar spine injury, based on the data of spiral computed tomography (SCT).Material and Methods. The study analyzed SCT data and case histories of 50 patients with thoracolumbar spinal cord injury operated on at different times after injury: up to 10 days – Group 1 and 11–30 days – Group 2. All patients underwent spinal reposition using a transpedicular device. The preoperative and postoperative SCT parameters were compared with the initial ones, which were calculated. The restoration of vertebral body heights and the elimination of deformation of the anterior spinal canal wall were compared in two groups depending on the distraction of interbody spaces and changes in the angle of segmental deformity.Results. In Group 1, the anterior and posterior dimensions of the vertebral body were restored, on average, by 95.3 ± 1.9 and 96.9 ± 1.4 % of the initial height; in Group 2 – by 87.4 ± 4.2 and 96.6 ± 1.8 %, respectively. The maximum restoration of the anterior dimensions of the vertebral bodies was achieved with distraction of the anterior interbody spaces closer to 100 % of the original size in the first and second groups. The maximum recovery of the posterior dimensions of the vertebral bodies was obtained by distraction of the posterior interbody spaces by 97 % or more of the original dimensions. The maximum elimination of the displacement of bone fragments from the spinal canal was obtained by distraction of the interbody spaces to a distance close to 100 % of the initial one, and when the obtained angle of segmental deformity coincided with the initial one.Conclusion. In the first 10 days after the injury, a greater percentage of the restoration of the anterior and posterior vertebral body heights and a decrease in the deformation of the anterior wall of the spinal canal were obtained. It was possible to maximally eliminate the deformation of the anterior wall of the spinal canal and restore the height of the anterior and posterior walls of the damaged vertebra by approaching the obtained dimensions of interbody spaces and the angle of segmental deformity to the initial ones.

Optimal Time–Jerk Trajectory Planning for Delta Parallel Robot Based on Improved Butterfly Optimization Algorithm

In this paper, a multi-objective integrated trajectory planning method based on an improved butterfly optimization algorithm (IBOA) is proposed, to improve the dynamic performance of the Delta parallel pickup robot in high-speed pick-and-place processes. The main objective of the present study is to improve dynamic positioning accuracy and running stability at high speeds and high accelerations. On the one hand, the intention is to ensure smooth motions using the trajectory planning method, and on the other hand to improve the picking efficiency. To this end, the pick-and-place trajectory of the robot is constructed by using NURBS curves in Cartesian space. Taking the time and jerk as the optimization objectives, a trajectory optimization method based on the improved butterfly optimization algorithm (IBOA) is proposed. The IBOA is based on the butterfly optimization algorithm (BOA); a circle chaotic sequence is introduced to replace the random initial population of the original BOA, and the fractional differential is used to improve the convergence speed of the BOA. Then, the problem of parallel segment deformation of the optimized trajectory is solved. Finally, a three-degrees-of-freedom Delta robot is used to evaluate the performance of the prosed algorithm. The obtained results show that, compared with other optimization algorithms, IBOA reduces the optimization time by 16.2%, and the maximum jerk is reduced by 87.6%. The results are better than the optimization results of other algorithms by 14.1% and 27.2%. The robot motion simulation results show that IBOA can effectively reduce the vibration acceleration of the end platform.

Predicting demographic characteristics from anterior segment OCT images with deep learning: A study protocol.

IntroductionAnterior segment optical coherence tomography (AS-OCT) is a non-contact, rapid, and high-resolution in vivo modality for imaging of the eyeball’s anterior segment structures. Because progressive anterior segment deformation is a hallmark of certain eye diseases such as angle-closure glaucoma, identification of AS-OCT structural changes over time is fundamental to their diagnosis and monitoring. Detection of pathologic damage, however, relies on the ability to differentiate it from normal, age-related structural changes.Methods and analysisThis proposed large-scale, retrospective cross-sectional study will determine whether demographic characteristics including age can be predicted from deep learning analysis of AS-OCT images; it will also assess the importance of specific anterior segment areas of the eyeball to the prediction. We plan to extract, from SUPREME®, a clinical data warehouse (CDW) of Seoul National University Hospital (SNUH; Seoul, South Korea), a list of patients (at least 2,000) who underwent AS-OCT imaging between 2008 and 2020. AS-OCT images as well as demographic characteristics including age, gender, height, weight and body mass index (BMI) will be collected from electronic medical records (EMRs). The dataset of horizontal AS-OCT images will be split into training (80%), validation (10%), and test (10%) datasets, and a Vision Transformer (ViT) model will be built to predict demographics. Gradient-weighted Class Activation Mapping (Grad-CAM) will be used to visualize the regions of AS-OCT images that contributed to the model’s decisions. The accuracy, sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve (AUC) will be applied to evaluate the model performance.ConclusionThis paper presents a study protocol for prediction of demographic characteristics from AS-OCT images of the eyeball using a deep learning model. The results of this study will aid clinicians in understanding and identifying age-related structural changes and other demographics-based structural differences.Trial registrationRegistration ID with open science framework: 10.17605/OSF.IO/FQ46X.

Cardiac Function Assessment in Fetuses With Ductus Arteriosus Constriction: A Two-Dimensional Echocardiography and FetalHQ Study.

BackgroundFetal ductal constriction (DC) is associated with excessive polyphenol-rich food (PRF) consumption during pregnancy. However, the effect of this hemodynamic change on fetal cardiac function still needs to be elucidated. Therefore, this study aimed to evaluate the cardiac function of fetuses with PRF-related DC and to describe serial observations of cardiac function changes.MethodsWe compared the traditional echocardiographic indices, including morphological, hemodynamic, and functional parameters, between study fetuses and controls. For global and segmental deformation analysis of the left and right ventricles, fetalHQ with the speckle-tracking technique was used to calculate sphericity index (SI), global longitudinal strain (GLS), fractional shortening (FS), fractional area change (FAC), etc. In addition, follow-up data were compared with the generalized linear model.ResultsA total of 60 DC fetuses and 60 gestational-matched controls were enrolled in our study, with 20 DC fetuses undertaking a follow-up echocardiogram after 2–3 weeks. Compared with controls, there was a distinct decrease in right ventricular GLS (RVGLS) (−13.39 ± 3.77 vs. −21.59 ± 2.51, p < 0.001), RVFAC (22.20 ± 9.56 vs. 36.01 ± 4.84, p < 0.001), left ventricular GLS (LVGLS) (−19.52 ± 3.24 vs. −23.81 ± 2.01 p < 0.001), and LVFAC (39.64 ± 7.32 vs. 44.89 ± 4.91, p = 0.004). For 24-segment FS analysis, DC fetuses showed lower FS in left ventricular (LV) segments 18–24, with no difference in LV segments 1–17. Right ventricular (RV) FS in segments 4–23 was also reduced in the DC group. The 24-segment SI analysis indicated significantly lower SI in DC than those in controls for LV segments 1–14 and RV segments 19–24. We found that the pulsatility index (PI) of ductus arteriosus (DA) was an independent variable for RVGLS (β = −0.29, p = 0.04). In 20 DC fetuses with follow-up echocardiograms, no obvious difference in myocardial deformation was found between the initial examination and follow-up data.ConclusionLeft and right ventricular performances were both impaired in DC fetuses, along with a series of morphological and hemodynamic changes. Although the state of DA constriction improved on second examinations, cardiac function was not completely restored.

Analysis of Shield Tunnel Ground Deformation Characteristics and Affecting Factors in Water-Rich Soft Stratum: A Case Study on the Section Tunnel of Tianjin Metro Line 6

With the increasing intensity of underground development, the planned metro lines will inevitably pass through water-rich soft stratum. The existing research results show that shield tunneling in water-rich stratum is prone to ground settlement and segment cracking due to the large moisture content and the low soil strength, which will pose risks to the safety of construction. The prediction of ground deformation characteristics and influencing ranges caused by shield tunneling in water-rich soft stratum has been a topical issue among the tunnel research community. Based on the shield tunnel project of Tianjin Metro Line 6, supported by the monitoring data, this paper analyses the ground deformation characteristics caused by shield tunneling in water-rich soft stratum. The results suggest that the surface settlement ranges from −14.20 mm to −28.00 mm in Tianjin’s water-rich soft stratum, which is at an acceptable level of engineering. A refined 3D model addressing fluid–structure interactions is developed to consider the construction process in water-rich soft stratum. Based on this technique, this article focuses on the effect of the support pressure at the excavation surface, the friction between the shield skin and the soil, and synchronous grouting quantity on the ground settlement and structural deformation. The results show that the friction between the shield skin and the soil is the most detrimental to deformation control, whereas the synchronous grouting quantity is the most advantageous to ground and segment deformation control. In practice, timely injection of bentonite slurry reduces friction between the shield skin and the soil, and effective synchronous grouting reduces shield tunneling disruption. This technique can provide calculation support in the optimization of shield tunneling schemes in water-rich soft stratum.

Using directional OCT to analyze photoreceptor visibility over AMD-related drusen

Investigators have reported reduced visibility of the cone photoreceptors overlying drusen using adaptive optics (AO) imaging techniques. Two hypotheses have been proposed to explain this phenomenon. First, the disease-related deformation of the photoreceptor outer segment (OS) may reduce its ability to act as a wave guide, thus decreasing the cell’s familiar reflectance pattern. Second, drusen could disorient the photoreceptors away from the eye’s pupil, reducing the amount of light reflected back out the pupil. In this work, we use directional OCT (dOCT) images of drusen in AMD patients to measure the respective contributions of these deforming and disorienting factors.

Измерение деформации поврежденных сегментов в грудном и поясничном отделах позвоночника по данным спиральной компьютерной томографии для расчета необходимой коррекции

Introduction The more accurate is the measurement of the parameters for correcting the deformity of damaged spinal segments the more accurate will be the restoration of the sagittal profile and original anatomy of the spine. Purpose Substantiation of calculated indicators for deformity correction in one or two damaged spinal motion segments in the thoracic and lumbar spine according to spiral computed tomography. Material and methods The material for the study was the results of spiral computed tomography (SCT) of an anatomically unchanged thoracic and lumbar spine in 25 patients (12 women and 13 men aged 18 to 60 years). The study model consisted of three vertebral bodies and four adjacent discs from T4 to L4. Anterior and posterior dimensions of the vertebral bodies, intervertebral discs, and segmental deformity angle α (formed by the lower endplate of the overlying vertebra and the upper endplate of the underlying vertebra) were measured using RadiAnt computer software in the midsagittal projection. Damage to the body of the middle vertebra with adjacent discs was modeled, the dimensions of which were calculated from the adjacent vertebral bodies and adjacent discs. Statistical processing of the material was carried out using the computer software SPSS Statistics. Results The measurement error of the anterior interbody spaces was 1.4 ± 0.4 mm, the posterior interbody spaces were 1.3 ± 0.5 mm, the error in calculating the segmental deformation angle α was 2.5 ± 0.6 degrees, what indicates the high accuracy of the proposed method. Discussion The use of absolute deformity values as a standard for surgical intervention in the treatment of vertebral fractures is complicated by varieties of normal anatomy. Conclusion The proposed calculations for the restoration of the anterior and posterior interbody distances, as well as the angle of segmental deformity α after a spinal cord injury of the thoracic and lumbar spine provide an approach to the target individualized anatomical dimensions.

Genetic Types of the tp12cx Strike-Slip Fault Segments and Their Role in Controlling Reservoirs in the Tarim Basin

The change of motion mode of multistage active strike-slip faults controls the segmentary types of strike-slip faults, which is seldom studied.Based on high-precision 3D seismic data and the principle of structural analysis, this paper defines the structural evolution characteristics of the tp12cx strike-slip fault in the key structural period and identifies the fault segmentation types. Combined with the statistical results of drilling production data and fault width, and fault width, it is demonstrated that different fault segments display various reservoir architecture and hydrocarbon potential. The tp12cx strike-slip fault experienced two phases of tectonic activity controlling reservoir development: the middle Caledonian and the late Caledonian to early Hercynian. During the middle Caledonian period, a left-lateral and left-step strike-slip fault was formed. The overlapping segments of the left steps were transtension zones, and the rest were pure strike-slip segments. From the late Caledonian to the early Hercynian, the movement mode changed from left-lateral to right-lateral, and the arrangement of left steps remained unchanged, forming right-lateral and left-step strike-slip faults. That is, as a weak zone, the transtension zones of all the preexisting overlapping segments took the lead in moving into many pure strike-slip segments and maintained the transtensional property. During the right-lateral slipping process of all the original pure strike-slip segments along the fault, they were blocked and squeezed by the surrounding rocks on both sides, forming a series of “positive” flower-shaped fault anticlines, which became overlapping segments, and the fault property became transpressional. Under the continuous action of the right-lateral slipping, a regional right-lateral and right-step strike slip fault formed. The interiors of the right-step-arranged faults were composed of the left-step arranged faults. Among them, the right-step overlapping segments were weakly step overlapping segments were weakly transtensional, and the larger the fault width of the internal left step pure strike slip and overlapping segments, the stronger the dissolution. The deformation of the right-step pure strike-slip segments was weak and basically maintained the characteristics of the previous stage. According to the evolution and superposition of pure strike-slipped and overlapped segments and the changes in fault properties, four types of strike-slip fault segments and corresponding reservoir models are divided. Type I: left-step pure strike-slip segment + left-step transpressional segment + right-step transtensional segment; Type II: left-step transtensional segment + left-step pure strike-slip segment + right-step transtensional segment; Type III: left-step pure strike-slip segment + left-step transpressional segment; and Type IV: left-step transtensional segment + left-step pure strike-slip segment. The fault width and oil production of type II and type IV with transtensional properties are much larger than those of type I and type III with transpressional properties.

P235 CLINICAL AND INSTRUMENTAL CORRELATES OF LEFT AND RIGHT ATRIAL TWO–DIMENSIONAL STRAIN MEASUREMENTS IN PATIENTS WITH HEART FAILURE

Abstract Background The two–dimensional strain obtained through Speckle Tracking Imaging (STI) represents an innovative, rapid and semi–automatic echocardiographic method to study systolic and diastolic function. By analyzing the deformation of cardiac segments, it provides an indirect index of myocardial contractility and relaxation of left and right ventricles, but also of both left and right atria. Purpose of the Study The aim of this study was to evaluate the clinical and instrumental correlates of the different measures of right and left atrial strain in a group of patients with chronic heart failure (CHF). Method. We enrolled 165 out patients with CHF (63 ± 14 years, 76% male, 39 ± 11% ejection fraction). All patients underwent a cardiological examination, ECG and echocardiogram. The echocardiographic images were analyzed using an innovative software (TomTec, Philips) able to semi–automatically analyze both the ventricular and atrial strain. For each patient, both for the left atrium (LA) and the right atrium (RA), the measures related to all atrial functional phases were calculated: reservoir (r), conduit (cd) and contraction (ct). Results At univariate and multivariate logistic regression models, the main determinants of atrial strain measurements were evaluated. As shown in the Table, both for the RA and LA the reservoir and conduit were more closely associated with ventricular systolic function and age. LA contraction was associated only with E/e‘ and heart rate, whereas for the RA one there was no independent statistical association with the parameters studied. Conclusions The Strain parameters that evaluate right and left atrial function have an independent association with different clinical and instrumental variables. These results support the hypothesis that the reservoir and conduit measurements express a different physiological and pathophysiological substrate than the contraction measures.

P121 ECHOCARDIOGRAPHIC EXAMINATION ON AGONIST ATHLETES WITH RECENT PAUCISYMPTOMATIC SARS COV 2 INFECTION, FOR THE RENEWAL OF AGONIST SPORT ACTIVITY ELIGIBILITY: PLAUSIBLE ROLE AND UTILITY OF GLS ANALYSIS THROUGH SPECKLE TRACKING

BackgroundThe aim of this work is to highlight whether or not the methodical echocardiography done through the analysis of global and segmental longitudinal deformation (GLS–SLS) can be useful to identify subclinical myocardial lesions in paucisymptomatic young agonist athletes with recent SarsCov2 infection before they return to agonist practice.Material and MethodsFrom 12/2020 to 12/2021 84 agonist athletes with previous SarsCov2 infection have been examined at “Cardiomed Center” Maglie (Lecce, IT), as part of screening for their return to sport practice; all of them under standard echocardiographic analysis associated to GLS analysis, Holter–ECG analysis with 24h on 12 derivations.ResultsThe base echocardiographic examination didn’t show any myocardial cynesis anomalies in any patient. In 5 patients there was a presence of a light pericardial effusion, how it was supposed to be as an outcome of a previous inflammatory ingjury The GLS analysis, that resulted in reliability considering the optimal acoustic window, showed a slightly lower medium value compared to the values cited in the literature (19.4 ± 2.9) and particularly 4 patients show considerable deficit reductions of segmentary strain. In these patients Holter analysis showed the presence of a moderate non–complex extrasystolic arrhythmia. These elements–that are a reduced GLS with marked regional anomaly, coupled with the presence of ventricular arrhythmia even in absence of segmentary dissinergyes– led to cardiac RMN evaluation. In 2 out of 4 patients there have been flaws that were compatible to modest myocardial lesions, in one case it was observed a marked flaw in medium–apical–lateral region that was correlated to the described areas at the specle tracking. ConclusionOur experience at the Cardiology and Sports integrated clinic, although it relied on a meager population of patients, it still demonstrated how echocardiographic analysis through GLS evaluation and the highlighting of sectorial alterations even in absence of cynesis anomalies can be used as a parameter to suppose the presence of miocarditic lesions that might be sent to the next RMN examination for confirmation, in young athletes with recent paucisymptomatic Covid–19 infection.

What's New in Spine Surgery.

What's New in Spine Surgery.

Calculation of the Natural Frequencies of a Fluid-Filled Pipe System With the Coupled Codes dyvro/rohr2: Implementation of an Alternative Coupling Concept

Abstract The vibration of a pipe system can be caused by internal excitation, e.g., as a result of pump-induced pressure pulsations or external excitation like earthquake. For the investigation of these phenomena, the knowledge about the natural frequencies of the pipe system is essential. In this context, it is important to consider that the natural frequencies of the coupled system of fluid and structure commonly differ from the natural frequencies of the pure fluid system and of the structural pipe model in which the fluid is only taken into account as added mass. To obtain realistic natural frequencies of a pipe system filled with a fluid, the one-dimensional fluid code dyvro was coupled with the code rohr2stoss that deals with dynamic analysis of complex piping and steel structures. Two code coupling concepts were realized, the integral concept, which is also commonly used in coupling commercial pipe system software, and the alternative local coupling concept, with which the longitudinal deformation of the pipe segments can be captured. Both concepts consider a two-way fluid–structure interaction (FSI). For the integral concept, a verification was performed by comparison with an analytical solution for a simple case with a fluid column connected to a spring–mass system. Additionally, both coupling concepts were validated by comparison with experimental data from literature that revealed strong FSI during a water hammer event. The frequency content of the measured pressure fluctuations could be captured by both coupling concepts.

Structural Stress Characteristics and Joint Deformation of Shield Tunnels Crossing Active Faults

Fault dislocation severely threatens the safety of a tunnel structure. Formerly, researchers mainly engaged in the mechanical response of mountain tunnels crossing the fault fracture zone. In contrast, few studies have focused on the structural stress characteristics and joint deformation of the cross-fault shield tunnels. There is an apparent difference between segmental tunnels and mountain tunnels with respect to mechanical properties. In the current study, a three-dimensional numerical model of cross-fault segmental tunnels is established based on the theory of concrete plastic damage constitutive relations using the finite element program ABAQUS. The numerical calculation results are compared with the model test results for validation. Subsequently, the relevant factors affecting the mechanical response of the shield tunnel crossing the active fault are analyzed. The results illustrate that when normal fault dislocation occurs, the shield tunnel structure is initially damaged appearing in the circumferential joints, which is prone to large tension deformation. Otherwise, when reverse faulting occurs by the same displacement, the shield tunnel structure is initially damaged at the arch haunch of the segments, and the deformation of the longitudinal joints is relatively slight. Under the same fault displacement, the bearing capacity of the segmental lining subjected to the reverse fault dislocation is more significant than that of the normal fault dislocation. Both the soil elastic modulus and the vertical distance between the top of the fault and the tunnel exert a considerable impact on the structural damage of the segmental tunnels, bolt stress, and joint deformation. The fault dip angle does not affect the mechanical characteristics of the shield tunnel structure when subjected to normal fault displacement. In reverse faulting cases, with the increase of the fault dip angle, the tunnel structural failure mode transforms from the transverse compression failure of the segments to the shear failure of the circumferential joints.

Design and Optimization of a Large-Stroke Compliant Constant-Torque Mechanism

Compliant constant-torque mechanism (CTM) can produce an output torque that does not change within a prescribed input rotation range. This stability is maintained regardless of complicated sensorized control systems. Owing to the monolithic nature of the compliant mechanism, the device is more compact, lightweight, and portable, which is favorable to human joint rehabilitative devices or mobility-assisting devices. However, before approaching the stable range, the mechanism has to undergo a pre-loading range which usually accounts for one-third of the entire operational journey. In addition, the deformation of flexible segments is restricted due to the yield strength of the materials. This limited working range hampers other potential applications of compliant CTMs. This paper presents a novel design of a compliant 2-stage CTM with long-stroke by using serially connected curved beams that deform sequentially. The design process is implemented via a shape optimization scheme using genetic algorithm. Finite element analysis is used to characterize the constant-torque behavior of the CTM under static loading. A general design formulation is also proposed to synthesize this special kind of compliant mechanism. The results show that this CTM gets the stable torque range from 300 to 1100 over two stages with the deviation less than 4.3%.

Effects of Kinesio taping on skin deformation during knee flexion and extension: a preliminary study

BackgroundKinesio Taping (KT) is proved useful to many musculoskeletal disorders. But the mechanism remains unclear. The kinesio tape works by sticking to the skin surface. So exploring the interaction between the tape and the skin and analyzing its biomechanical influence may be an effective way to explore the mechanism of the tape.ObjectivesThis study aimed to investigate the effect of Kinesio taping and taping methods on skin deformation during knee joint flexion and extension motion and further explore its possible functional mechanisms.MethodsTen healthy and pain-free subjects (4 males, 6 females) were recruited in this study. The skin observation area on the anterior side of the right thigh of the subjects was divided into 11 segments by 12 reflective marker points for distance measurement, from the distal knee to the proximal knee, the length of the interval was L1 to L11, and the total length was L0. Subjects were treated with no KT (NT), resting positive taping (RPT), resting negative taping (RNT), stretching positive taping (SPT), and stretching negative taping (SNT). A Qualisys infrared high-speed three-dimensional spatial coordinate capture system was used to observe changes in the length of the observed skin surface on the right anterior thigh during right knee flexion and extension in the sitting position.ResultsDuring right knee flexion and extension in the seated position in 10 subjects, all skin segment deformations produced significant differences between intervention groups (P < 0.05), except for L1 during flexion (P = 0.07). During right knee flexion and extension, total length, L0, and spacing lengths, L1, L6, and L11, were longer in the NT group than in all other groups. L0 and L1 were both longer in the stretched position than in the rest position; L11 also showed this trend.ConclusionsThe usage of the KT had an effect on the biomechanical changes of the skin, resulting in changes in skin deformation. I-tape, natural tension taping can shorten the skin distance between the two ends of the tape. Limb position during taping may influence the KT’s effects. However, the change in taping direction showed no significant effects on skin deformation during exercise. KT may apply a pre-stress in the biomechanics of the skin.

Outcomes of Pediatric Scaphoid Nonunions Treated With Distal Radius Cancellous Autograft.

The optimal management of pediatric scaphoid fracture nonunions is controversial. We hypothesize that pediatric patients with scaphoid fracture nonunions will have favorable functional outcomes with the utilization of nonvascularized distal radius cancellous autograft with open reduction and internal fixation (ORIF). A review was performed from 2012 to 2017 identifying skeletally immature patients with scaphoid fracture nonunions treated with ORIF and nonvascularized distal radius cancellous autograft, including demographic data, mechanism of injury, length of time from injury to treatment, operative procedure, length of immobilization, time to union, and complications. Ten patients (9 males, 1 female) met inclusion criteria. Mean age was 14.3 SD 1.5 years. The majority of fractures were sustained during sports or secondary to a fall. Mean time between injury and orthopaedic evaluation was 33 weeks (SD 20 wk). Eight fractures occurred at the waist, and 2 occurred at the proximal pole. Four patients had a humpback deformity, and three presented with a dorsal intercalated segmental instability deformity. Nine patients were treated with a single cannulated compression screw with distal radius autograft. One patient also received a single Kirschner wire fixation in addition to a single cannulated screw and graft. Patients underwent a mean postoperative immobilization period of 14 SD 5 weeks. Two patients received a bone stimulator postoperatively. Radiographic union was documented after initial surgery in nine patients, with mean time to union of 17 SD 5 weeks. The 1 patient with persistent radiographic nonunion underwent revision fixation and repeat nonvascularized distal radius autograft, achieving union and resolution of symptoms. All patients ultimately reported full return to activity. Pediatric scaphoid fracture nonunions that undergo ORIF using nonvascularized distal radius cancellous autograft have favorable rates of consolidation and functional outcomes. Surgeons should consider this source of grafting in operative management of scaphoid nonunions in children and adolescents. Level IV, therapeutic.

A new approach to artefact detection and its effect on the normal range of segmental strain and strain rate values

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Helse Nord HNF1458-19 Background Definition of normal ranges of myocardial segmental deformation are important in clinical studies and routine echocardiographic practice. It is known that artefacts hamper segmental strain and strain rate (S/SR) analysis. Purpose This study is based on a new approach for artefact detection. We intended to investigate to what degree different types of artefacts and their localization bias the result of measurements and to establish corrected normal ranges for segmental S/SR parameters. Methods The study is based on a collaboration project between the Russian cross-sectional study "Know your heart" and the Norwegian "Tromso-7" study. From 2207 participants we identified 840 individuals (511 females and 329 males, age range 40-79) with normal cardiac function by excluding left ventricular ejection fraction &amp;lt;50%, moderate or severe valvular heart disease, LV- dilatation, pulmonary hypertension, Q-waves and bundle branch block signs on ECG, high blood pressure, history of heart attack, use of antihypertensive drugs or high level of NT-proBNP. End-systolic longitudinal epi- myo- and endocardial strain and peak systolic SR and diastolic SR E and SR A were assessed for the calculation of segmental normal ranges. In addition to noise and foreshortening artefacts, we introduced a concept of "curve artefact" which can be defined as unphysiological strain curve shapes. Panel A of the figure shows examples of these curve artefacts, A: diastolic mismatch B: blunted curve, and C: floating curve. All strain curves were assessed for the presence of one of these unphysiological shapes and 2D images were visually assessed for the presence of noise, reverberations, or missing parts of the myocardium. Results The bar-chart for segmental strain demonstrates significantly reduced strain values at the presence of curve artefacts and increased strain at the presence of foreshortening. Normal ranges for basal septal, basal, medial, and apical segments excluding segments with artefacts and foreshortening are displayed in the table. The presence of curve artefacts matched the presence of noise or other 2D image artefacts in 88% of cases. Conclusions Strain artefacts result in systematically reduced peak-strain values. Thus, the detection and exclusion of curve artefacts seem to be an important measure for the correct interpretation of strain curves for a definition of normalcy and pathology. The selection of artefact-free strain curves reveals high strain and SR gradients increasing from epi to endocardial position and basal-septal towards apical segments. Abstract Figure. normal range Abstract Figure. artefacts

Mechanical response of inclined TBM tunnel due to drainage settlement of deep sandstone aquifer

Drainage of deep aquifers can cause stratum settlement, which has significant effects on the architectural structures within them. Especially for inclined TBM tunnels, the settlement may lead to the longitudinal differential deformation and damage of segments. However, most previous studies on the effects of aquifer drainage settlement on deep structures have focused on the vertical shaft in coal mines, and little attention has been paid to inclined TBM tunnels in deep sandstone aquifers. Through the physical model test and numerical simulation, in this study, the mechanical characteristics and deformation behavior of an inclined TBM tunnel in the deep water-bearing sandstone and impermeable mudstone before and after the aquifer drainage were investigated. The distribution and variation of stresses, internal forces, and deformation on tunnel segments before and after drainage were systematically analyzed along the tunnel longitudinal and circumferential directions. Results show that the whole tunnel is always under compression and mainly subjected to the coupling effect of bending moment and axial compression in the longitudinal direction. After drainage, the longitudinal and circumferential stresses as well as circumferential axial force increase remarkably at the tunnel sidewall but decrease at the tunnel crown and invert. While for the circumferential bending moment, by contrast, it increases at the three positions. In addition, the tunnel experiences a noticeable bending at the junction of the two strata after drainage due to the synchronous settlement with the sandstone, resulting in severe stress concentrations and the formation of the longitudinal shear band at the stratigraphic junction.

Research on the Reuse of Discharged Soil from EBP Shield Tunnels in Synchronous Grouting Material

Great practical significance and engineering application value can be achieved when the large amount of discharged soil produced by EPB shield tunnels is recycled and comprehensively utilized. As one of the key processes of shield construction, synchronous grouting needs a large amount of bentonite, cement, fly ash, sand, and other materials. The research on the reuse of shield muck as synchronous grouting material is carried out based on Zhengzhou subway project. The physical properties and phase of the discharged soil from EPB shield tunnels are studied by using laboratory tests and XRD. The statistics show that the shield muck meets the performance requirements of bentonite and fine sand in synchronous grouting materials. The optimal grout ratio of the reused muck is obtained based on the optimization idea of multiobjective programming by MATLAB. Considering the combined effect of seepage field, stress field, and the timeliness of the grout, the influences of grouting pressure and the filling rate of synchronous grouting on surface settlement, plastic zone of strata, and segment deformation are analyzed by using finite difference method. The results prove that the surface settlement and segment deformation can be better controlled when the grouting pressure is at 0.18 MPa and the grouting rate is at 120%–150%.

Accuracy of Tibia Deformity Correction with a Hexapod Multiplanar External Fixator with Measurements Taken from Radiographs, CT Scan, and Imaging Software: A Cadaveric Study

Category:Other; TraumaIntroduction/Purpose:The success of hexapod multiplanar external fixators for correction of tibial deformity has been well described. The ability to correct deformity is based on the accuracy of the reference and deformity data inputted into the prescription program. If the data is not accurate, multiple residual programs may be required for final correction. There are limited papers evaluating i accuracy of intraoperative measurements. We are unaware of any analysis on the use of CT scan to determine deformity and reference points. Newer software program allows surgeons to incorporate radiographs into the correction program to determine deformity and reference points. Our study objective was to compare deformity and reference point measurements taken from radiographs, CT, and imaging software to determine which method most accurately corrects tibia deformities.Methods:Hexapod external fixators were orthogonally applied on four full length tibia cadavers. Strut lengths were set to the same length. Each cadaver was assigned a different deformity: proximal quartile, distal quartile, midshaft, and segmental. An osteotomy was performed and the hexapod struts were loosened to create a multiplanar deformity. Radiographs and CT were taken orthogonal to the reference ring. Deformity and reference points were measured off each according to correction software data points. Pictures of the radiographs were imported into the software program (Stryker, Mahwah, NJ) and the correction reference points were determined with imaging software. All cadavers had a correction program for each method. Two surgeons performed the measurements twice to determine inter and intra-observer accuracy. Corrections were performed and post reduction radiographs were measured to determine length, angulation and translation. In addition, the total number of millimeters each strut was off from the pre-deformity position was recorded.Results:Line technique on software program was significantly better at measuring segmental deformity and the Image technique was statistically more accurate to correct proximal, midshaft and distal deformities (p<0.05). Overall, all methods were more accurate correcting Midshaft and Proximal deformities (44.8mm and 50.4mm, respectively) significantly better than Distal and Segmental deformity correction (88.9mm and 121.7mm, respectively (p<0.001). There was no difference in absolute measurements or intra-observer error between the four surgeons (p>0.05).Conclusion:Compared to the traditional method of measuring deformity and frame reference using radiographs, new imaging software appears to be superior and more reproducible in correcting tibia deformities. Surgeons should recognize the increased difficulty in correcting segmental and distal deformities regardless of the method used. Accuracy of determining deformity and frame reference points has the potential to decrease time patients are in a frame and reduces the potential for malunions. Further investigation is needed to determine sites of variation to further improve the process of correcting complex deformities of the tibia.