Cross-sectional Area Research Articles

Assessment of residual resistant capacity of cold-formed Q1100 ultra-high strength steel channel section stub column with corrosion

Experiment and numerical analysis were conducted in this study to reveal the residual resistant capacity of the cold-formed Q1100 ultra-high strength steel (UHSS) channel section stub column with grooving corrosion. Based on the results of tensile coupon test, the strength properties of the Q1100 UHSS were barely changed by the cold-forming process. A clear reduction in the ductile properties was observed, after the cold-forming process. The load-end shortening curve of the cold-formed Q1100 UHSS channel section stub columns with different grooving corrosions were obtained through the axial compressive experiment. The initial resistant stiffness was reduced by the grooving corrosion significantly, because of the reduction in the cross-section area. Decrease in the corrosion angle and increment in the corrosion length enhanced the adverse effects of grooving corrosion on the resistant capacity. Local buckling was observed in the flange and web. The flanges near the corrosion weakening area were more prone to local buckling, because of the stress transfer from web to flange. A numerical modelling method was proposed to simulate the resistant performance of the cold-formed Q1100 UHSS channel section stub columns with different grooving corrosions, which was validated by the comparison in load-end shortening curve, ultimate resistance and failure mode. Effects of corrosion angle, corrosion length, and corrosion location on the resistant capacity and failure mode were investigated through the parametric study. Compared with corrosion location, the corrosion angle and corrosion length exhibited more significant effects on the resistant capacity of the cold-formed Q1100 UHSS channel section stub columns.

Quadriceps muscle quality and quantity following tibial plateau fracture repair.

To investigate the qualitative and quantitative changes seen in quadriceps muscles [QM] following tibial plateau fracture and surgery. A consecutive series of patients with an isolated tibial plateau fracture presenting to a single academic center were enrolled and prospectively followed. Bilateral knee MRIs were performed preoperatively and 3 and 12 months postoperatively to assess quantity and quality of the quadriceps muscles. All patients underwent tibial plateau operative repair and were made non-weight-bearing for 10 weeks postoperatively then advanced to weight-bearing as tolerated. Functional status assessed via the short musculoskeletal functional assessment (SMFA); knee range of motion [ROM]; vastus medialis oblique [VMO] and vastus lateralis [VL] muscle quantity (axial width, cross sectional area [CSA] and volume) on injured and contralateral limb; VMO, sartorius, semi-membranous and biceps femoris [BF] muscle quality (fat and water content, and proton density fat fraction). All muscle quantitative and qualitative measurements were compared across all time points. Ten patients were included in the final analysis, 6 males and 4 females, with average age of 43.62 ± 16.3years. While the VMO and VL axial width and CSA were significantly decreased at 3months preoperatively, this was not statistically significant. There was no significant difference between any QM quantitative measurements at any time points. There was no difference in fat content, water content or PDFF at any time point for the VMO, sartorius, semi-membranous and BF muscles. Regression analysis also showed no association between 12-month SMFA scores and knee ROM with VMO/VL CSA at 1year. QM quantity and quality do not significantly change at 3months and 1year postoperatively following tibial plateau fracture surgery. Prognostic Level II.

Production and Characterization of Melt-Spun Poly(3-hydroxybutyrate)/Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) Blend Monofilaments.

We investigated the melt-spinning potential of a poly(3-hydroxybutyrate)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blend using a piston spinning machine with two different spinneret diameters (0.2 and 0.5 mm). Results from the differential scanning calorimetry, dynamic mechanical thermal analysis, and tensile testing showed distinct filament properties depending on the monofilaments' cross-sectional area. Finer filaments possessed different melting behaviors compared to the coarser filaments and the neat polymer, indicating the formation of a different type of polymer crystal. Additionally, the mechanical properties of the finer filament (tensile strength: 21.5 MPa and elongation at break: 341%) differed markedly from the coarser filament (tensile strength: 11.7 MPa, elongation at break: 12.3%). The hydrolytic stability of the filaments was evaluated for 7 weeks in a phosphate-buffered saline solution and showed a considerably reduced elongation at break of the thinner filaments. Overall, the results indicate considerable potential for further filament improvements to facilitate textile processing.

Brain and cervical spinal cord MRI correlates of sensorimotor impairment in patients with multiple sclerosis.

Cervical spinal cord (cSC) lesions and atrophy contribute to disability in multiple sclerosis (MS), but associations with specific sensorimotor dysfunction require further exploration. To investigate the associations of brain and cSC magnetic resonance imaging (MRI) measures with sensorimotor impairment in MS. One hundred fifty-one MS patients and 69 healthy controls underwent 3T MRI and clinical assessments including Expanded Disability Status Scale (EDSS), 9-hole peg test (9-HPT), finger tapping test (FTT), timed 25-foot walk test (T25FWT), and vibration detection threshold (VDT). Random forest ranked brain (T2-hyperintense lesion volume (T2-LV) and normalized deep gray matter (GM), cortical and white matter (WM) volumes) and cSC (T2-LV and total, GM, and WM cross-sectional areas (CSAs) at C2/C3 level) MRI measures relevance in explaining EDSS milestones (EDSS ⩾3.0, ⩾4.0, and ⩾6.0), VDT, pyramidal and sensory functional systems (P-FS and S-FS ⩾2), and motor tests impairment. Various combinations of brain and cSC MRI measures explained EDSS milestones (area under the curve (AUC) =0.879-0.900), VDT (R2 = 0.194), and impaired P-FS (AUC = 0.820), S-FS (AUC = 0.795), 9-HPT (AUC = 0.793), FTT (AUC = 0.740), and T25FWT (AUC = 0.825). cSC GM CSA was the most informative feature for all outcomes, except 9-HPT. cSC MRI measures, especially GM CSA, explain EDSS and sensorimotor dysfunction better than brain measures in MS.

Ultrasound Measurements of the Ulnar Nerve at the Medial Epicondyle Correlate With Electrodiagnostic Studies.

Cubital tunnel syndrome is the second most common compressive neuropathy in the upper extremity and is commonly evaluated with electrodiagnostic studies (EDS). Ultrasound (US) has emerged as a potentially more efficient alternative to EDS. The purpose of this study is to evaluate whether measurements of the cross-sectional area (CSA) of the ulnar nerve at the elbow correlate with EDS results. This study was a prospective analysis of patients who presented with signs and symptoms consistent of cubital tunnel syndrome, who received USs of the ulnar nerve at the elbow and nerve conduction tests. Pearson correlation coefficients were used to evaluate the correlation between ulnar nerve CSA and electrodiagnostic data. t Tests were used to evaluate statistical differences between the mean ulnar nerve CSA of patients with positive or negative nerve conduction study results. Youden Index was used to calculate the optimal cut-off point for US CSA based on maximal sensitivity and specificity. Statistical significance was based on a two-sided P less than .05. The association between increasing US CSA at the medial epicondyle with slowing of the conduction velocity of the ulnar motor nerve across the elbow was statistically significant (r = -0.35, P = .02). Patients with positive EDS tests had significantly larger nerve size than those with negative tests (all Ps < .03). A cut-off point of greater than or equal to 11 mm2 had a sensitivity of 70.83% and specificity of 66.67%. Larger ulnar nerve CSAs correlate with slowing of the conduction velocity on EDSs, and those with positive EDSs have larger nerve sizes than those with negative tests.

Efficacy and safety of tesamorelin in people with hiv on integrase inhibitors.

Tesamorelin is the only FDA-approved therapy to treat abdominal fat accumulation in people with HIV (PWH). Phase III clinical trials were conducted prior to the introduction of integrase inhibitors (INSTIs), which are now a mainstay of HIV antiretroviral therapy. We leveraged a randomized double-blind trial of 61 PWH and metabolic dysfunction-associated steatotic liver disease to evaluate the efficacy and safety of tesamorelin 2 mg once daily versus identical placebo among participants on INSTI-based regimens at baseline. In the parent clinical trial, visceral fat cross-sectional area, hepatic fat fraction, and trunk-to-appendicular fat ratio were quantified using magnetic resonance imaging, proton magnetic resonance spectroscopy, and dual-energy x-ray absorptiometry, respectively, at baseline and 12 months. Metabolic and safety outcomes were compared between treatment arms. Among 38 participants on INSTI-based regimens at baseline, 15 individuals on tesamorelin and 16 individuals on placebo completed the 12-month study. Tesamorelin led to significant declines in visceral fat (median [interquartile range]: -25 [-93, -2] vs. 14 [3, 41] cm2, P = 0.001), hepatic fat (-4.2% [-12.3%, -2.7%] vs. -0.5% [-3.9%, 2.7%], P = 0.01), and trunk-to-appendicular fat ratio (-0.1 [-0.3, 0.0] vs. 0.0 [-0.1, 0.1], P = 0.03). Tesamorelin was well-tolerated with a similar frequency of adverse events including hyperglycemia between groups. The current analysis provides the first dedicated data on the efficacy and safety of tesamorelin among PWH on INSTI-based regimens. Despite the association of INSTI use with weight gain and adipose tissue dysfunction, tesamorelin had beneficial effects on body composition with no exacerbation of glycemic control.

Sonographic imaging of the stellate ganglion in healthy adults: An observational study.

The aim of this study is to estimate the normal cross-sectional area and diameter of the stellate ganglion (SG) by ultrasound (US) in healthy adults. The study sample included 80 stellate ganglia in 40 participants (15 males, 25 females), mean age 38 years, mean height 162.5 cm, mean weight 67.8 kg, mean body mass index 25.4 kg/m2. Two radiologists separately obtained US images of the bilateral SG. Each participant was scanned 3 times bilaterally to assess for intra-observer reliability. The mean diameter of the SG was 1 mm (range: 0.1-2). The mean CSA of the bilateral SG was 1.3 mm2 (range: 0.6-3.9). The SG diameter positively correlated with age. Our study demonstrates the ability of US to image the SG and estimate its normal diameter and CSA. Knowledge of how to identify and measure the SG during ultrasound-guided procedures would be expected to decrease the risk of associated complications and help establish normal reference values.

Optimization of cold-formed steel beam cross-sections for pallet rack storage systems

This paper aims to obtain optimized cold-formed beam cross-sections for industrial pallet rack storage systems. The optimal sections were obtained by applying fitness functions aimed at reducing cross-sectional area and/or displacement and solving them using the Genetic Algorithm. These functions imposed a behavioral constraint so that all optimized solutions had the same resistant bending moment. The calculation of the characteristic resistant bending moment was carried out according to the direct strength method, with load factors defined by the elastic stability analysis with CUFSM, in an analysis routine implemented on the MATLAB platform. Four parameterized sections were studied, verifying the optimum set of height, width and stiffening elements that met the objectives defined by functions, assuming reference values of a rectangular hollow section. Manufacturing constraints were also taken into account. The results show that it is possible to manufacture cold-formed beams that consume less material and/or have a better moment of inertia in relation to the reference section, without compromising the strength of the structural element.

Low muscle density in children with osteogenesis imperfecta using opportunistic low-dose chest CT: a case-control study

BackgroundThe aim of the study was to investigate the muscle differences in children with osteogenesis imperfecta (OI) using opportunistic low-dose chest CT and to compare different methods for the segmentation of muscle in children.MethodsThis single center retrospective study enrolled children with OI and controls undergoing opportunistic low-dose chest CT obtained during the COVID pandemic. From the CT images, muscle size (cross-sectional area) and density (mean Hounsfield Units [HU]) of the trunk muscles were measured at the mid-T4 and the mid-T10 level using two methods, the fixed thresholds and the Gaussian mixture model. The Bland-Altman method was also used to compute the strength of agreement between two methods. Comparison of muscle results between OI and controls were analyzed with Student t tests.Results20 children with OI (mean age, 9.1 ± 3.3 years, 15 males) and 40 age- and sex-matched controls were enrolled. Mean differences between two methods were good. Children with OI had lower T4 and T10 muscle density than controls measured by the fixed thresholds (41.2 HU vs. 48.0 HU, p < 0.01; 37.3 HU vs. 45.9 HU, p < 0.01). However, children with OI had lower T4 muscle size, T4 muscle density, T10 muscle size and T10 muscle density than controls measured by the Gaussian mixture model (110.9 vs. 127.2 cm2, p = 0.03; 44.6 HU vs. 51.3 HU, p < 0.01; 72.6 vs. 88.0 cm2, p = 0.01; 41.6 HU vs. 50.3 HU, p < 0.01, respectively).ConclusionsChildren with OI had lower trunk muscle density indicating that OI might also impair muscle quality. Moreover, the fixed thresholds may not be suitable for segmentation of muscle in children.

Dynamic analysis of extensible beam with multiple cracks

We present the governing equation and study vibrations of multiple crack beams undergoing large deflections subject to transverse loads. First, the primary motion equation is derived using Hamilton’s principle applied to energy functions accounting for cracks. Then we derive a normalized equation governing the vibration of the extensible cracked beam. Single and multiple crack beam examples are considered and analyzed numerically to verify the validity of the derived equations. We propose a modified cracked extensible beam model accounting for the axial force by considering the reduced cross-sectional area. It is expressed by a new reduction parameter. Using the proposed model, we numerically investigate how the cracked extensible beam’s natural frequencies change depending on various model parameters.

Use of 3D-CT-derived psoas major muscle volume in defining sarcopenia in colorectal cancer

BackgroundSarcopenia is characterized by reduced skeletal muscle volume and is a condition that is prevalent among elderly patients and associated with poor prognosis as a comorbidity in malignancies. Given the aging population over 80 years old in Japan, an understanding of malignancies, including colorectal cancer (CRC), complicated by sarcopenia is increasingly important. Therefore, the focus of this study is on a novel and practical diagnostic approach of assessment of psoas major muscle volume (PV) using 3-dimensional computed tomography (3D-CT) in diagnosis of sarcopenia in patients with CRC.MethodsThe subjects were 150 patients aged ≥ 80 years with CRC who underwent primary tumor resection at Juntendo University Hospital between 2004 and 2017. 3D-CT measurement of PV and conventional CT measurement of the psoas major muscle cross-sectional area (PA) were used to identify sarcopenia (group S) and non-sarcopenia (group nS) cases. Clinicopathological characteristics, operative results, postoperative complications, and prognosis were compared between these groups.ResultsThe S:nS ratios were 15:135 for the PV method and 52:98 for the PA method. There was a strong positive correlation (r = 0.66, p < 0.01) between PVI (psoas major muscle volume index) and PAI (psoas major muscle cross-sectional area index), which were calculated by dividing PV or PA by the square of height. Surgical results and postoperative complications did not differ significantly in the S and nS groups defined using each method. Overall survival was worse in group S compared to group nS identified by PV (p < 0.01), but not significantly different in groups S and nS identified by PA (p = 0.77). A Cox proportional hazards model for OS identified group S by PV as an independent predictor of a poor prognosis (p < 0.05), whereas group S by PA was not a predictor of prognosis (p = 0.60).ConclusionsThe PV method for identifying sarcopenia in elderly patients with CRC is more practical and sensitive for prediction of a poor prognosis compared to the conventional method.

Genotype-specific spinal cord damage in spinocerebellar ataxias: an ENIGMA-Ataxia study

BackgroundSpinal cord damage is a feature of many spinocerebellar ataxias (SCAs), but well-powered in vivo studies are lacking and links with disease severity and progression remain unclear. Here we characterise...

Probing membrane deformation energy by KcsA potassium channel gating under varied membrane thickness and tension.

This study investigated how membrane thickness and tension modify the gating of KcsA potassium channels when simultaneously varied. The KcsA channel undergoes global conformational changes upon gating: expansion of the cross-sectional area and longitudinal shortening upon opening. Thus, membranes impose differential effects on the open and closed conformations, such as hydrophobic mismatches. Here, the single-channel open probability was recorded in the contact bubble bilayer, by which variable thickness membranes under a defined tension were applied. A fully open channel in thin membranes turned to sporadic openings in thick membranes, where the channel responded moderately to tension increase. Quantitative gating analysis prompted the hypothesis that tension augmented the membrane deformation energy when hydrophobic mismatch was enhanced in thick membranes.

Influence of structure parameters of pre-chamber on lean combustion of active pre-chamber jet ignition engine

Turbulent jet ignition (TJI) technology has the potential to improve engine efficiency. To elucidate the influence of different factors (diameter and number of holes) affecting the nozzle's total cross-sectional area, internal structure of the pre-chamber, and nozzle angle on the combustion characteristics of the engine. A 3 × 3 orthogonal test was designed and machined. The experiments were carried out on a pre-chamber single-cylinder engine.The results show that the pre-chamber's internal volume ratio has a great effect on the combustion characteristics in the cylinder. While the volume ratio of top of pre-chamber, transition region, and pre-chamber throat is 1:1:1, the engine's peak heat release rate is the highest. The highest Indicated thermal efficiency (ITE) can reach 43.43 %, with an absolute increase of 1.24 %, and the lean burn limit can reach λ = 2.6. Too large or too small nozzle angle will worsen the combustion state in the cylinder. The aperture and Nozzle number, which are the factors influencing the nozzle's total cross-sectional area, have different effects on the ignition delay, CA10-CA50, and CA50-CA90 of the engine. Various factors affecting the nozzle's total cross-sectional area have no apparent influence on the changing trend of ITE, but the aperture greatly influences ITE.

Effect of varying cuff sizes with identical inner diameter on endotracheal intubation in critically ill adults: A sealed tracheal controlled trial.

The present study aims to determine the impact of different cuff diameters on the cuff pressure of endotracheal tubes (ETTs) when the trachea is adequately sealed. In the present single-center clinical trial, adult patients who underwent cardiothoracic surgery were assigned to use ETTs from 2 brands (GME and GZW). The primary endpoint comprised of the following: cuff diameter, inner diameter of the ETT, manufacturer, and the number of subjects with tracheal leakage when the cuff pressure was 30 cm H2O. A total of 298 patients were assigned into 2 groups, based on the 2 distinct brands of ETTs: experimental group (n = 122, GME brand) and control group (n = 176, GZW brand). There were no significant differences in baseline characteristics. However, the cuff diameter was significantly smaller in the control group, when compared to the experimental group (P = .001), and the incidence of tracheal leakage was significantly higher in the control group (P = .001). Furthermore, the GME brand ETT had a significantly larger cuff diameter, when compared to the GZW brand ETT. The cuff size would mismatch the tracheal area in clinical practice. Therefore, chest computed tomography is recommended to routinely evaluate the tracheal cross-sectional area during anesthesia, in order to ensure the appropriate cuff size selection.

Investigation of the relationship between plasma ghrelin levels and muscle atrophy in experimental diabetic rats

In this study, the relationship between plasma ghrelin levels and muscle atrophy was examined in an experimental diabetic rat model. 56 male Wistar albino rats, aged 8-10 weeks, were used in the study. The rats were divided into 8 groupsD1: one-week diabetes, C1: one-week control, D2: three-week diabetes, C2: three-week control, D3: six-week diabetes, C3: six-week control, D4: eight-week diabetes, C4: eight-week control. To induce diabetes, rats were injected with a single intraperitoneal dose of 45 mg/kg streptozotocin. At the end of the experiments, body weights and fasting blood sugar levels were measured. mTOR and myostatin levels of gastrocnemius muscle and plasma ghrelin levels were measured by ELISA method. Gastrocnemius muscle weight, cross-sectional area and histopathological images were examined. It was observed that the gastrocnemius weights of the D2, D3, D4 groups decreased significantly compared to their controls (p≤0.01). Muscle cross-sectional area decreased significantly in groups D3 and D4 compared to controls (p≤0.01). Muscle mTOR levels were found to be significantly lower in all diabetic groups compared to controls (p≤0.01). Although muscle myostatin levels were higher in the diabetic groups, this increase was only significant in the D4 group. Plasma ghrelin levels were significantly lower in all diabetic groups compared to controls (p≤0.01). A positive correlation was determined between plasma ghrelin levels and the final weights, muscle cross-sectional area, gastrocnemius weights and mTOR levels of the rats. Time-dependent muscle atrophy developed in diabetic rats and there was a relationship between muscle atrophy and plasma ghrelin level. We suggest that ghrelin plays a role in diabetes-induced muscle atrophy as well as cachexia and sarcopenia.

The Technique of Inorganic Core Sand Shooting with Reduced Pressure in Venting System

The publication presents a new shooting technique with reduced pressure in venting system for manufacturing foundry cores using inorganic sand mixture with Cordis binder. Traditional technologies for producing casting cores using blowing methods, despite their undeniable advantages, including the ability to produce cores in series, also come with some disadvantages. The primary drawbacks of the process involve uneven compaction structure of the cores, with denser areas primarily located under the blow holes, and under-shooting defects, which often occur in regions away from the blow hole or in increased core cross-sectional areas. In an effort to improve core quality, a concept was developed that involves incorporating a reduced pressure in the core box venting system to support the basic overpressure process. The solutions proposed in the publication with a vacuum method of filling the cavities of multi-chamber core boxes solve a number of technical problems occurring in conventional blowing technologies. It eliminates difficulties associated with evacuating the sand from the chamber to the shooting head and into technological cavity and increases the uniform distribution and initial degree of compacting of grains in the cavity. The additive role of this “underpressure” support is to enhance corebox venting by eliminating 'air cushions' in crevices and structural elements that obstruct the flow of evacuated air. The publication presents the results of studies on core manufacturing using blowing methods conducted in three variants: classic overpressure, utilizing the core box filling phenomenon by reducing pressure, and an integrated approach combining both these methods.

Three-dimensional characterization of particle size, shape, and internal porosity for Apollo 11 and Apollo 14 lunar regolith and JSC-1A lunar regolith soil simulant

Samples of soils collected by the Apollo 11 mission (10084,2036) and the Apollo 14 mission (14163,940) were obtained from the NASA Curation and Analysis Planning Team for Extraterrestrial Materials (CAPTEM) program. The particle size, shape, and internal porosity were characterized in three dimensions (3D) using a combination of X-ray computed tomography (XCT) and mathematical analysis, with various size and shape parameters measured and calculated for each particle. High-resolution scanning electron microscopy (SEM) was used to image the particles that were too small for the two XCT instruments used. Similar characterization was carried out on samples of JSC-1A lunar soil simulant, updating a previous analysis. Approximately 14,000 lunar regolith particles and 128,000 JSC1-A particles, covering a wide range of size and shape, were characterized for this paper and the results stored in a publicly accessible database. This large number of particles enabled, for the first time, statistically valid particle shape distributions to be generated. The 3D shape distributions of the two regoliths and JSC-1A were quantitatively compared and it was found that the way particle shape and porosity depends on particle size was different between regolith and simulant. The measured size distribution of particles in the lunar soils was applied to estimate the relative contributions of different sizes to the ensemble average particle single scattering albedo and phase function. By linking our particle counts to published sieve weight fractions for the lunar samples, we find that ∼80% of the total cross-section area is contributed by particles <20 μm diameter and ∼ 50% by particles <8 μm diameter. The orientation-averaged two-dimensional projected areas of the actual regolith particles were computed so that this estimate was also based on real particle shapes. Such small sizes dominating the total cross-section area suggest that calculations of the elements of the scattering matrix for individual particles may be possible with modest computing capabilities leading to the development of improved models for the quantitative interpretation of remote sensing spectrophotometry and polarimetry. This 3D characterization and database will enable other computational work to be done with real lunar regolith particle shapes, including discrete element method mechanical modeling, packing simulations, further light scattering calculations, dust contamination modeling, and modeling of lunar rover interactions with collected and packed regolith particles.

Uniportal Full-endoscopic Foraminotomy for Lumbar Foraminal Stenosis: Clinical Characteristics and Functional Outcomes.

Uniportal full-endoscopic foraminotomy offers a promising alternative to conventional surgical methods for individuals afflicted by lumbar foraminal stenosis. This study aims to evaluate the efficacy and clinical outcomes of uniportal full-endoscopic foraminotomy in patients diagnosed with lumbar foraminal stenosis. A comprehensive retrospective analysis was conducted on individuals who underwent full-endoscopic foraminotomy in our medical center, between January 2018 and December 2019. The investigation encompassed the demographic data of patients and key clinical metrics such as the visual analogue scale of leg (VAS-L) and back pain (VAS-B), Oswestry disability index (ODI) scores, the Short Form-36 Health Survey physical component summary (SF-36 PCS) and the mental component summary (SF-36 MCS), as well as modified MacNab grades, were systematically assessed and compared. Furthermore, radiological parameters: Coronal Cobb angle (CCA), Intervertebral angle changes (IAC), Disc height index (DHI), the foraminal cross-sectional area (FCSA) and the FCSA enlargement ratio were also compared. A variety of statistical analyses including Student t-test, chi-square tests, Fisher's exact tests, Pearson's and Spearman's correlation analyses, and Interclass Correlation Coefficients (ICCs) were employed. 64 patients, including 34 males and 30 females were enrolled. The mean follow-up period extended to 22.66 ± 7.05 months. Distribution by affected segments revealed 26.6% at L4-5, 67.1% at L5-S1 level, and 6.25% at both L4-L5 and L5-S1 levels. At the final follow-up, VAS-L decreased from 7.26 ± 1.19 to 1.37 ± 1.25, while VAS-B decreased from 6.95 ± 0.54 to 1.62 ± 1.13 (p < 0.001). ODI score also demonstrated a substantial decrease from 74.73 ± 8.68 to 23.27 ± 8.71 (p < 0.001). Both SF-36 PCS and SF-36 MCS scores improved significantly (p < 0.001). Modified MacNab criteria revealed 58 excellent-good patients (90.7%), and 6 fair-poor patients (9.3%). No significant differences were founded in the CCA (p = 0.1065), IAC (p = 0.5544), and DHI (p = 0.1348) between pre-operation and the final follow-up. However, the FCSA significantly increased from 73.41 ± 11.75 to 173.40 ± 18.62 mm2 (p < 0.001), and the enlargement ratio was 142.9% ± 49.58%. Notably, the final follow-up FCSA and the FCSA enlargement ratio were found to be larger in the excellent and good group compared to the fair and poor group, according to the modified MacNab criteria. The utilization of uniportal full-endoscopic foraminotomy has demonstrated its safety and efficacy in addressing lumbar foraminal stenosis. The clinical success of this procedure appears to be closely associated with the radiological decompression of the intervertebral foramen area. Importantly, the application of this technology does not seem to compromise the overall stability of the lumbar region.

Determination of muscle shape deformations of the tibialis anterior during dynamic contractions using 3D ultrasound.

In this paper, we introduce a novel method for determining 3D deformations of the human tibialis anterior (TA) muscle during dynamic movements using 3D ultrasound. An existing automated 3D ultrasound system is used for data acquisition, which consists of three moveable axes, along which the probe can move. While the subjects perform continuous plantar- and dorsiflexion movements in two different controlled velocities, the ultrasound probe sweeps cyclically from the ankle to the knee along the anterior shin. The ankle joint angle can be determined using reflective motion capture markers. Since we considered the movement direction of the foot, i.e., active or passive TA, four conditions occur: slow active, slow passive, fast active, fast passive. By employing an algorithm which defines ankle joint angle intervals, i.e., intervals of range of motion (ROM), 3D images of the volumes during movement can be reconstructed. We found constant muscle volumes between different muscle lengths, i.e., ROM intervals. The results show an increase in mean cross-sectional area (CSA) for TA muscle shortening. Furthermore, a shift in maximum CSA towards the proximal side of the muscle could be observed for muscle shortening. We found significantly different maximum CSA values between the fast active and all other conditions, which might be caused by higher muscle activation due to the faster velocity. In summary, we present a method for determining muscle volume deformation during dynamic contraction using ultrasound, which will enable future empirical studies and 3D computational models of skeletal muscles.