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The study refers to the application of a type of artificial neural network called the Self-Organising Map (SOM) for the identification of areas of the human abdominal wall that behave in a similar mechanical way. The research is based on data acquired during in vivo tests using the digital image correlation technique (DIC). The mechanical behaviour of the human abdominal wall is analysed during changing intra-abdominal pressure. SOM allow to study simultaneously three variables in four time/load steps. The variables refer to the principal strains and their directions. SOM classifies all the abdominal surface data points into clusters that behave similarly in accordance with the 12 variables. The analysis of the clusters provides a better insight into abdominal wall deformation and its evolution under pressure than when observing a single mechanical variable. The presented results may provide a better understanding of the mechanics of the living human abdominal wall. It might be particularly useful when selecting proper implants as well as for the design of surgical meshes for the treatment of abdominal hernias, which would be mechanically compatible with identified regions of the human anterior abdominal wall, and possibly open the way for patient-specific solutions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background and Objective: Ventral hernia repair is faced with high recurrence rates. The personalization of the diagnosis, the surgical approach and the choice of the prosthetic implant seem relevant axes to improve the current results. Numerical models have the potential to allow this patient-specific approach, yet currently existing models lack validation. This work extensively investigated a realistic finite element abdominal wall model including the implementation of muscle activation., Methods: A parametric 3D finite element model composed of bone, muscle and aponeurotic structures was introduced. Hyperelastic anisotropic materials were implemented. Two loading scenarios were simulated: passive inflation of the abdominal cavity to represent, e.g., breathing, and passive inflation followed by muscular activation to simulate other daily activities such as cough. The impact of the inter-individual variability (e.g., BMI, tissue thickness, material properties, intra-abdominal pressure (IAP) and muscle contractility) on the model outputs was studied through a sensitivity analysis., Results: The overall model predictions were in good agreement with the experimental data in terms of shape variation, muscles displacements, strains and midline forces. A total of 34 and 41 runs were computed for the passive and active sensitivity analysis respectively. The regression model fits rendered high R-squared in both passive (84.0 ± 6.7 %) and active conditions (82.0 ± 8.3 %). IAP and muscle thickness were the most influential factors for the selected outputs during passive (breathing) activities. Maximum isometric stress, muscle thickness and pre-activation IAP were found to drive the response of the simulations involving muscular contraction. The material properties of the connective tissue were essential contributors to the behaviour of the medial part of the abdominal wall., Conclusions: This work extensively investigated a realistic abdominal wall model and evaluated its robustness using experimental data from literature. Such a model could improve patient-specific simulation for ventral hernia surgical planning, prevention, and repair or implant evaluation. Further investigations will be conducted to evaluate the impact of the surgical technique and the mechanical characteristic of prosthetic meshes on the model outputs., Competing Interests: Declaration of competing interest This work was supported by Medtronic, Trévoux, France. The authors have no conflicts of interest and nothing to disclose., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background and Objective: Biomechanical assessment of the abdominal wall represents a major prerequisite for a better understanding of physiological and pathological situations such as hernia, post-delivery recovery, muscle dystrophy or sarcopenia. Such an assessment is challenging and requires muscular deformations quantification which have been very scarcely reported in vivo. In the present study, we intended to characterize abdominal wall deformations in passive and active conditions using dynamic MRI combined to a semiautomatic segmentation procedure., Methods: Dynamic deformations resulting from three complementary exercises i.e. forced breathing, coughing and Valsalva maneuver were mapped in a transversal abdominal plane and so for twenty healthy volunteers. Real-time dynamic MRI series were acquired at a rate of 182 ms per image, then segmented semi-automatically to follow muscles deformation through each exercise. Circumferential and radial strains of each abdominal muscle were computed from the geometrical characteristics' quantification, namely the medial axis length and the thickness. Muscular radial displacement maps were computed using image registration., Results: Large variations in circumferential and radial strains were observed for the lateral muscles (LM) but remained low for the rectus abdominis muscles (RA). Contraction phases of each exercise led to LM muscle shortening down to -9.6 ± 5.9% during Valsalva maneuver with a 16.2 ± 9.6% thickness increase. Contraction also led to inward radial displacement of the LM up to 9.9 ± 4.1 mm during coughing. During maximal inhalation, a significant 10.0 ± 6.6% lengthening was quantified for LM while a significant thickness decrease was computed for the whole set of muscles (-14.7 ± 6.6% for LM and -7.3 ± 6.5% for RA). The largest displacement was observed for the medial part of RA (17.9 ± 8.0 mm) whereas the posterior part of LM underwent limited motion (2.8 ± 2.3 mm). Displacement rate and correlation between muscle thickness and medial axis length during each exercise provided insights regarding subject-specific muscle function., Conclusions: Dynamic MRI is a promising tool for the assessment of the abdominal wall motion and deformations. The corresponding metrics which have been continuously recorded during the exercises provided global and regional quantitative information. These metrics offer perspectives for a genuine clinical evaluation tool dedicated to the assessment of abdominal muscles function in both healthy subjects and patients., Competing Interests: Conflict of interest statement The authors have no conflicts of interest and nothing to disclose., (Copyright © 2022. Published by Elsevier B.V.)

Bovine pericardium(BP)is one of the biological membranes with extensive application in tissue engineering. To fully investigate the potential clinical applications of this natural biological material, a suitable cross-linking reagent is hopefully adopted for modification. Glutaraldehyde (GA) is a clinically most common synthetic cross-linking reagent. In the study, oxidized hyaluronic acid (AHA) was developed to substitute GA to fix acellular bovine pericardium (ABP) for lower cytotoxicity, aiming to evaluate the feasibility of AHA as a cross-linking reagent and develop AHA-fixed ABP as a biological patch for abdominal wall repair. The AHA with the feeding ratio (1.8:1.0) has an appropriate molecular weight and oxidation degree, almost no cytotoxicity and good cross-linking effect. The critical cross-linking characteristics and cytocompatibility of AHA-fixed ABP were also investigated. The results demonstrated that 2.0% AHA-fixed ABP had the most suitable mechanical properties, thermal stability, resistance to enzymatic degradation and hydrophilicity. Moreover, 2.0% AHA-fixed samples exhibited an excellent cytocompatibility with human peritoneal mesothelial cells (HPMC) and low antigenicity. It also showed a prominent anti-calcification ability required for abdominal wall repair. Our data provided experimental basis for future research on AHA as a new cross-linking reagent and AHA-fixed ABP for abdominal wall repair., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Chest radiographs should be obtained at the peak of inspiration so that radiological findings can be precisely interpreted. However, this is not easily achieved, particularly in young children who do not follow the instruction to hold their breath. We developed a sensor that detects the breathing movements and conducted a randomized controlled study to determine whether the sensor would increase the proportion of chest radiographs obtained in the inspiration phase. We recruited 124 infants and children aged less than 3 years, who visited the pediatric department of a general hospital in Tokyo, Japan, and allocated them into one of two groups: with-sensor and without-sensor groups. Overall, 81% of all images were obtained during inspiration. The proportion of chest radiographs taken during inspiration was not statistically different between the two groups (81% vs. 82%). In the with-sensor group, radiologic technologists were able to obtain chest radiographs of the same quality while not observing the chest movement, but the sensor. The use of the sensor did not increase the proportion of chest radiographs taken in the inspiration phase in this study. However, this null result may indicate the possibility of utilizing the sensor for automatizing chest radiography in the future.

Introduction: In severe asthma, management of life-threatening air trapping that persists despite initiation of standard asthma treatment is difficult in the absence of extracorporeal membranous oxygenation. Case study: Three children with life-threatening asthma could not be adequately ventilated despite maximum conventional treatment because of severe air trapping. A novel method of active expiration by abdominal compression with a standard ventilator was adopted with immediate effect with significant improvement in ventilation. Conclusion: Synchronized abdominal compression is a novel and simple method that allows an effective treatment of severe air trapping in an intubated paralyzed asthma child.

Background: This study is the first to correlate sonographic findings of subcutaneous tissue to structural and biomechanical properties., Methods: Precisely sized tissue specimens (59 samples) were collected from five abdominoplasty procedures. A Philips Lumify L12-4 linear array probe, connected to an Android tablet, was used to obtain ultrasound images of the superficial fascial system. A no. 1 Vicryl suture on a CTX needle placed though a needle guide within a three-dimensionally printed template ensured equal bites of subcutaneous tissue across specimens. Suture pull-out strength was measured until failure at a displacement rate of 2.12 mm/second using an Admet MTEST Quattro. Mean gray value for the superficial fascial system in associated ultrasonographic images was quantified by CellProfiler., Results: Superficial fascial system visualization can be accomplished using high-resolution portable ultrasound. Comparing multiple specimens' imaging, interpatient and intrapatient variability of superficial fascial system quantity and structural characteristics are apparent. The superficial fascial system is highly abundant in some patients, but has limited presence in others. Individual-specimen mean gray value and whole-patient mean gray value positively correlated with tissue tensile strength (p = 0.006) and patient-average tissue tensile strength (p = 0.036), respectively. Whole-patient mean gray value accounted for 98.5 percent of the variance seen in patient-average tensile strength, making it a strong predictor for tensile strength., Conclusions: Portable ultrasound and image-processing technology can visualize, quantify, and predict subcutaneous tissue strength of the superficial fascial system. The superficial fascial system quantity correlates with suture tensile strength. Clinically, preoperative superficial fascial system quantification may aid in outcome predictions, manage patient expectations, and potentially lower complication rates., Clinical Question/level of Evidence: Diagnostic, V.

Objective: Laparoscopic surgery in children is often hampered by limited working space. This is partially compensated by stretching the child's abdominal wall. The volume of space that can be gained and changes to abdominal wall elasticity with respect to age are unknown. In the current research, we studied the extent of abdominal wall elasticity while establishing pneumoperitoneum in children., Methods: One hundred and sixty three children less than 18 years of age, undergoing elective laparoscopic surgery were recruited for the study. After induction of general anesthesia with a standardized muscle relaxant dose, a length of 5 cm was marked above, below and lateral to the umbilicus. The length of the marking was measured under increasing intraabdominal pressure (IAP of 0, 4, 6, 8, 10, 12 mmHg). The measurements were repeated to assess the effect of prestretching. The patients were divided into two groups: infants (less than one year of age) and older children (more than one year of age)., Results: Depending on the age and axes of the measurements, a child's abdomen stretches up to 17% on average, with induction of pneumoperitoneum. The percentage of stretch tapers off as the IAP approaches peak pressure. As children become older, the longitudinal abdominal wall elasticity decreases, but the transverse abdominal wall elasticity increases. Regardless of age, prestretching results in a statistically significant increase in the elasticity over the transverse and lower sagittal abdominal wall., Conclusion: A child's abdominal wall has considerable expandability. The characteristics of elasticity change depending on the axis and age. Prestretching can improve intraabdominal working space. This knowledge is helpful in port position design for minimally invasive surgery in children., Level of Evidence: Level II., (Copyright © 2019. Published by Elsevier Inc.)

Objectives: To inform selective and efficient use of appendix ultrasound (US) beyond adult parameters of body mass index (BMI) of less than 25 kg/m, we correlate abdominal wall thickness (AWT) with age and BMI to generate parameters for male and female children. Information presented in chart format can aid in the decision to utilize US for the evaluation of appendicitis., Methods: In this observational study, 1600 pediatric computed tomography scans of the abdomen and pelvis were analyzed to obtain measurements of AWT in the right lower quadrant. Measurements were correlated by patient age, BMI, and sex. Results and consensus-based recommendations were presented in chart format with color-coded groupings to allow for convenient referencing in the clinical setting., Results: One thousand four hundred eighty-eight computed tomography scans and AWT measurements were included. All age groups with BMI of less than 25 kg/m and all male and female groups younger than 6 years regardless of BMI had median AWT of less than 4 cm resulting in strong recommendation for US. Males older than 6 years and all female age groups with BMI of greater than 30 kg/m and female older than 15 years and BMI of greater than 25 kg/m had AWT of more than 5 cm resulting in low recommendation for US., Conclusions: While the BMI cutoff standard of less than 25 kg/m for usefulness of appendix US holds in the adult population, our data expand the acceptable range in children younger than 9 years regardless of BMI and male children with BMI up to 30 kg/m. Female children younger than 15 years with a BMI up to 30 kg/m may also be amenable to right lower quadrant US based on AWT. These parameters inform selective and efficient use of US for appendix evaluation.

Background: Male and female hernia patients often have different surgical history, fat distribution, and medical comorbidities. Female surgical patients seemingly experience worse outcomes after open ventral hernia repair. This study evaluates the impact of sex and the distribution of abdominal adiposity on outcomes after open ventral hernia repair., Methods: A prospective hernia database was queried for patients from 2007 to 2018 with a computed tomography within 1 year of open ventral hernia repair. Three-dimensional volumetric analysis was performed. Demographics, abdominal fat distribution, operative characteristics, and outcomes were evaluated by sex using univariate and multivariate analysis., Results: A total of 1,178 patients were identified, 57.8% were female. Compared with males, females had higher mean body mass index (34.8 ± 8.5 vs 31.7 ± 6.4 kg/m 2 , P < .0001), previous abdominal operations (3.3 ± 1.5 vs 2.6 ± 1.3, P < .0001), and preoperative chronic pain (33.5 vs 26.4%, P = .009). There was no difference in history of recurrence, age, steroid use, smoking, diabetes, or hernia volume between sexes (P ≥ .17 all values). Males had larger defects (168.1 ± 148.2 vs 138.8 ± 126.8 cm 2 , P = .001) and intra-abdominal volume (intra-abdominal fat volume; 6,279 ± 2,614 vs 4,454 ± 2,196 cm 3 , P < .0001). Females had larger subcutaneous fat volume (subcutaneous fat volume; 7,453 ± 6,600 vs 5,708 ± 3,275 cm 3 , P < .0001), and ratio of hernia to intra-abdominal volume (hernia volume to intra-abdominal fat volume; 0.33 ± 0.52 vs 0.22 ± 0.42, P < .0001). On univariate analysis, females had higher rates of readmission, wound complication, and intervention for pain after open ventral hernia repair (P ≤ .02 all values). On multivariate analysis, females had shorter duration of stay (-1.36 day, standard error 0.49, P = .006) with higher readmission rate (odd ratio, 1.64; 95% confidence interval, 1.15-2.34)., Conclusion: Female hernia patients in our population are more comorbid, with higher body mass index, thicker subcutaneous fat volume and a higher ratio of hernia volume to intra-abdominal fat volume. These differences are associated with more extensive surgical intervention, such as panniculectomy and higher rates of adverse outcomes after open ventral hernia repair. However, these differences are not fully explained by identified comorbidities and warrant further investigation., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: To reveal the relationship between abdominal movement and artifact, and to reveal if the transient artifact in arterial phase is caused by transient abdominal movement (TAM) in contrast-enhanced (CE) MRI., Materials and Methods: 325 CE-MRI series (206 with EOB and 119 with EGCM) were included. The abdominal movement was classified into three groups by respiratory bellows waveform (= bellows grade, BG 1-3), and MR image quality (= artifact score, AS) was graded 1-5 for the precontrast, arterial and portal venous phase, respectively. The relationship between the BG and AS was evaluated. The occurrence of transient artifact in arterial phase was compared to the degree of TAM., Results: In the acquisitions with BG3, all images showed AS of > 2, while no images had AS of > 4 in the acquisitions with BG1. Numbers of transient artifact in the arterial phase with no-abdominal movement (NAM), mild-TAM, severe-TAM were 0 of 120, 4 of 27, 7 of 8 in EOB and 0 of 91, 1 of 4, 0 of 0 in EGCM, respectively., Conclusion: Image quality is highly correlated with abdominal movement. Moreover, artifact in arterial phase was not observed in NAM, which indicated abdominal movement is the direct cause of artifact.

In spinal muscular atrophy (SMA), respiratory muscles are heterogeneously involved with a weakness of the intercostal muscles, possibly of the abdominal wall muscles, and a relatively spared diaphragm, resulting in cough impairment. An abnormal inspiratory cough phase pattern has been reported in SMA II and III. This short communication analyzed the esogastric pressures during voluntary cough in 49 SMA II and III patients. Four different patterns of coughing, reflecting an increasing degree of respiratory muscle weakness, were identified. The "mild weakness" profile was observed mainly in SMA III, while the "severe weakness" profile, which seems to correspond to the absence of abdominal muscle activity, was observed only in a few patients with SMA II. The cough profiles of 6 patients are presented together with their sniff and maximal static pressures measurements. Different esogastric pressure patterns were observed during these forceful maneuvers, suggesting variable involvement of the intercostal and abdominal muscles, and diaphragm during the evolution of SMA II and III., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background and Objective: Abdominal hernia repair is one of the most often performed surgical procedures worldwide. Numerical simulations of the abdominal wall mechanics can be a valuable tool to devise actions aimed at preventing hernia formation. A first step towards this goal is the development of consistent constitutive models for the tissues that form the human abdominal wall. In this study we propose, for each of the tissues involved, a new formulation of the so-called transversely isotropic hyperelastic model (TIHM)., Methods: We propose a new TIHM for the human abdominal wall tissues and we present a systemic view of the methodology that we have implemented in the present study. First we consider the mathematical background of the TIHM. The novelty of our formulation is that both the isotropic and the fiber contributions to the strain energy function are characterized exclusively by polynomial convex functions of certain invariant quantities. Then, we provide a detailed description on how the constitutive model is implemented into an open source finite element (FE) software. In our approach we use the specific interface provided by the MFront software to incorporate our TIHM formulation into the Code Aster FE solver. For each of the tissues considered, the values of the TIHM constants are adjusted by means of a numerical simulation of previous experimental data from tensile tests., Results: We studied the following abdominal wall tissues: linea alba, rectus sheath, external oblique muscle, internal oblique muscle, transversus abdominis muscle and rectus abdominis muscle. Our formulation closely reproduces tensile test data for each tissue in the corresponding FE numerical simulation., Conclusions: The new TIHM formulation is suitable for a future numerical investigation of the abdominal wall, which will in turn help us to assess the best zone to practice a colostomy. The methodology implemented in the present study can be easily extended in the future to develop and implement a TIHM for active muscles and/or a different type of constitutive model which might be suitable to characterize other tissues of biomedical interest., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Tension is one of the most discussed terms related to hernia surgery and repair. Despite the universally accepted opinion that tension and reduction of tension are important concepts in hernia repair, there is very little known about the physiologic tension of the abdominal wall related to ventral hernia repair. The purpose of this project was to attempt to measure physiologic tension in patients without hernia repair and help determine a normal baseline tension. Patients were enrolled in a prospective institutional review board-approved protocol to measure abdominal wall tension from February 2014 to present. Patients undergoing abdominal surgery without hernia repair were included. Demographic information and operative details were documented. Abdominal wall tensions were measured using scales attached to Kocher clamps that are clamped to the fascia and then brought together in the midline. Total tension, surgeon's estimation of tension, and grading of the fascia were recorded. Descriptive statistics were calculated. Eleven patients met the inclusion criteria and had tension measurements performed during surgery. The average age was 58 years, with 55 per cent of them being white and 82 per cent being male, with an average BMI of 27. Operations included exploratory laparotomy for small bowel pathology in six patients, colorectal surgery in three patients, and splenectomy in a trauma patient. Average tension measurements for these patients were 1.9 lbs. Surgeon grading of tension was an average of 2.2 (range, 1-5). Obtaining tension measurements is feasible during abdominal surgery. Physiologic tension seems to be approximately 2 pounds. Further study is needed with a larger sample of patients.

Background and objectives: Doppler ultrasound of umbilical and fetal vessels is useful for monitoring fetal well-being, fetal anemia, intrauterine growth retardation, and other perinatal outcomes. The adverse perinatal outcome and circulatory changes can be reflected in fetal Doppler studies. The aim of this study was to evaluate the effect of increased pressure exerted on the maternal abdominal wall during routine ultrasound on the middle cerebral artery (MCA), resistance index (RI), pulsatility index (PI), and peak systolic velocity (PSV). Materials and Methods: A prospective study was conducted, in which we included 40 pregnant women between 24 + 0 and 41 + 3 gestational weeks (GW), with singleton pregnancies, without any associated pathologies, undergoing routine US examination. We recorded the flow velocity waveforms in the MCA, and we measured the RI, PI, PSV, and the applied pressure on to the maternal abdominal wall-needed for a proper evaluation of MCA. We then repeated the same measurements at two different higher pressure levels, at the same time having a proper image of the targeted vessel. Results: We found significant differences for the PI and RI levels with an increase in abdominal pressure (median PI 1.46, 1.58, and 1.92, respectively; median RI 0.74, 0.78, and 0.85, respectively; p < 0.05), for both PI and RI. At the same time, we found no significant differences for PSV in the studied group in relationship with increase in abdominal pressure (median PSV 39.56, 40.10, and 39.70, respectively; p > 0.05). Conclusions: The applied abdominal pressure by the examiner's hand, during routine US scan in pregnancy, can modify the MCA parameters of blood flow resistance (PI and RI) when measured by Doppler US, thus influencing the diagnostic accuracy in a series of pregnancy associated pathologies, such as chronic fetal distress (CFD) or intrauterine growth restriction (IUGR)., Competing Interests: The authors declare no conflict of interest. The authors alone are responsible for the content and writing of the paper.

Background: Clarifying the biomechanics of abdominal skin could lead to different uses for this tissue such as the ventral repair of hernias in patients with excess skin and incisional hernias. The objective of this study was to compare the maximum tensile strength of abdominal skin to commercial meshes and to verify whether or not it varies between aesthetic patients and massive weight-loss patients., Methods: Experimental cross-sectional study. Skin samples sized 32 × 20 mm were taken from 15 abdominoplasties and 10 panniculectomies. The skin specimens were analyzed in vertical and horizontal tensile strength tests. Results were compared between the two groups including their traction directions. Commercial meshes were also tested. The results were analyzed using the Generalized Estimating Equation., Results: The maximum tensile strength supported vertically by abdominal dermis was 403.5 ± 27.4 N in the abdominoplasty group and 425.9 ± 33.9 N in the panniculectomy group. Horizontally, the values were 596.5 ± 32.2 N and 612.5 ± 43.9 N respectively. The strengths between traction directions were significantly different (p < 0.001). There were no differences between the groups with regard to the maximum tensile strength (p = 0.472). Tested commercial meshes had the following values: polypropylene 104.6 N, low-weight polypropylene 54.4 N, polytetrafluorethylene (PTFE) 82.2 N, and hydrated porcine small-intestinal submucosa 60.0 N., Conclusion: In our study, the tensile strength of the tested human abdominal dermis samples, both aesthetic and post-bariatric, was superior to the commercial meshes. Therefore, in selected cases, abdominal dermis could be an alternative tool in abdominal reconstruction during panniculectomies with concomitant hernia repair.

Repetitive mechanical load applied to a body part may lead to hypertrophy of its muscles. If a movement requires asymmetric activation of bilateral muscles, this may result in differences in muscle size between the sides. This study aimed to investigate the degree of bilateral differences in the trunk muscle volume of golfers by comparing with non-golfers. Seventeen male right-handed golfers and eleven (nine right- and two left-handed) non-golfers participated. Trunk muscle volume was determined using magnetic resonance imaging, and the degree of asymmetry was calculated as the ratio of trunk muscle volume on the left to trunk muscle volume on the right side in right-handers and vice-versa in left-handers. Golfers had significantly larger lateral abdominal wall (LA) muscle volume than non-golfers: 12.36 ± 1.12 vs. 9.96 ± 0.94 cm3/kg; erector spinae: 9.12 ± 1.16 vs. 7.88 ± 0.84 cm3/kg; psoas major (PM): 6.27 ± 0.88 vs. 5.51 ± 0.98 cm3/kg; rectus abdominis (RA): 4.15 ± 0.54 vs. 3.50 ± 0.64 cm3/kg; and multifidus: 3.61 ± 0.41 vs. 3.05 ± 0.40 cm3/kg (p < 0.05). The degree of bilateral asymmetry of the LA, PM, and RA volume was significantly greater in golfers than in non-golfers (LA: -8.63 ± 7.40% vs. 1.94 ± 2.76%; PM: -9.10 ± 5.25% vs. -0.48 ± 5.96%; RA: 6.36 ± 6.50% vs. -2.12 ± 9.64%, respectively, p < 0.05). Right-handed golfers had greater left LA and PM volume compared to the right (LA: 5.89 ± 0.55 vs. 6.48 ± 0.65 cm3/kg; PM: 3.00 ± 0.42 vs. 3.27 ± 0.47 cm3/kg; p < 0.05) and had greater right RA volume compared to the left (2.15 ± 0.32 vs. 2.00 ± 0.24 cm3/kg, p < 0.05). These findings suggest that skilled, long-term golfers develop large volume and bilateral asymmetry of their trunk muscles., Competing Interests: The authors have declared that no competing interests exist.

Abdominal wall biomechanics is strongly affected by muscular contraction and intra-abdominal pressure (IAP) which characterize different physiological functions and daily tasks. However, the active muscular behavior is generally not considered in current computational models of the abdominal wall. The aim of this study is to develop a numerical model mimicking muscular activation and IAP. A three dimensional Finite Element model of a healthy abdominal wall is developed detailing the principal abdomen components reconstructed upon anatomical data and medical images. Fascial tissues, aponeuroses and linea alba are modelled as hyperelastic fiber-reinforced materials, while a three-element Hill's model is assumed for muscles. Numerical analyses are performed increasing the IAP up to 100 mmHg and simultaneously activating the muscular structures. The obtained abdominal behavior is compared to a similar model with same IAPs, but passive muscles conditions. Abdomen stiffness and strength are computed in regions in which hernias can potentially occur. A global stiffening of the abdominal wall is found corresponding to a low abdomen deformation and the membrane force on fascial structures is reduced by muscular contraction. Representing active muscular contraction leads to advanced findings, otherwise membrane force results overestimated considering a purely passive behavior for the abdominal wall.

Background and Objectives: Limited information is available on how weight loss intervention programs affect skeletal muscle mass especially in trunk., Methods and Study Design: A total of 235 overweight Japanese men and women aged 40-64 years with a body mass index of 28.0 to 44.8 kg/m2 participated in this randomized controlled intervention study. They were randomly divided into a lifestyle intervention group and control group. Before and after the one-year lifestyle intervention for weight loss an abdominal transverse image was acquired by computed tomography. The cross-sectional areas (CSAs) of visceral fat, subcutaneous fat, and skeletal muscle of rectus abdominis, abdominal oblique, iliopsoas, and erector spinae muscle were calculated., Results: The body weight changed by approximately -5% in the intervention groups. The corresponding values for subcutaneous fat and visceral fat CSAs were -10.8 to -17.5% in both sexes. The reductions observed in skeletal muscle CSAs were significantly less (-6.0% and -7.2% in the men and women intervention groups respectively) than those in fat tissue CSAs. The CSA of each of the four skeletal muscle groups also significantly decreased; however, after adjustments for body weight at each time point, only reductions in the iliopsoas muscle in both sex and abdominal oblique muscles in men remained significant., Conclusions: The lifestyle weight loss intervention might reduce the relative amount of the abdominal skeletal muscles especially in iliopsoas muscle.

Introduction: Incisional negative pressure wound therapy (iNPWT) has been of recent interest in different surgical fields as beneficial outcomes on high-risk wounds have been reported. Nevertheless, its mechanisms of function are not widely studied to date., Methods: We established two ex vivo setups of iNPWT in porcine and human abdominal wall for measuring pressures within the wound which result from iNPWT application. For pressure measurements, a high-resolution manometry catheter and a balloon catheter probe were used in a wound sealed with either a commercially available PREVENA VAC kit or a self-made iNPWT kit. Furthermore, we evaluated seroma evacuation by iNPWT., Results: Both setups showed similar characteristics of pressure curves within the wound when applying increasing negative pressures. Application of high pressures did not result in a similar increase in wound pressure. Only subtotal evacuation of seroma by iNPWT application (about 75% of volume) could be detected., Conclusion: Our ex vivo model of iNPWT in porcine and human abdominal wall could show reproducible measurements of pressures within the wounds in both types of tissue. As intrawound pressures did not increase in the same way as the applied negative pressure, we suggest that our results do not advocate the idea of using iNPWT for wound care especially as seroma evacuation remains insufficient.

It is universal to repair abdominal wall defects with prosthetic materials in abdominal surgery worldwide, which are associated with high complications and organ damage. At present, the composite nanofibers composed of natural and synthetic polymers as the new type of nano structure scaffold have attracted considerable attention in the field of tissue engineering. In this study we examined the feasibility of using electrospun silk fibroin (SF)/poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) hybrid scaffolds for repairing of abdominal wall defects. Both in vivo and in vitro characterization were evaluated to access efficacy of the nanofiber for tissue regeneration. Our results showed that the electrospun SF/PHBV nanofiber scaffolds could stimulate the expression of TGF-β1 and Collagen I in fibroblasts in vitro and then promote granulation and connective tissue depositions, but not result in a strong foreign body reaction in vivo. Moreover, we conjectured the potential molecular biological mechanism of SF/PHBV hybrid scaffolds in the process of tissue regeneration. Thus, the SF/PHBV hybrid nanofiber scaffolds have high efficiency and biocompatibility to repair abdominal wall defects., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objective: The present quasi-experimental study aimed to assess the transversus abdominis (TrA), internal oblique (IO) and external oblique (EO) thickness in healthy subjects with the proprioceptive Stabilizer™ training in abdominal wall muscles., Methods: A sample of 41 healthy participants (age: 31.9 ± 4.5 y; height: 1.7 ± 0.1 m; weight: 68.3 ± 13.1 kg; body mass index, BMI: 22.9 ± 2.7 kg/m2) were recruited to participate in this study. Ultrasound images of the EO, IO, TrA, rectus anterior (RA) and interrecti distance (IRD) were measured and analyzed by the ImageJ software. Measurements were made at rest and during the abdominal drawing-maneuver (ADIM) developed by the patients with the Stabilizer™ located in the low back holding 40 mmHg for 10 seconds with a visual stimulus provided by a circular pressure marker., Results: Ultrasound measurements for the abdominal wall muscles showed statistically significant differences (Π < .05) for a thickness decrease of the EO, IO and a thickness increase of TrA. A proprioceptive Stabilizer™ training produced a thickness increase in TrA muscle and a thickness decrease in EO and IO muscles in healthy subjects., Conclusions: These findings suggest that a proprioceptive Stabilizer™ training could be useful in individuals with low back pain and lumbopelvic pain.

Purpose: Airway protective behaviors, like cough and swallow, deteriorate in many populations suffering from neurologic disorders. While coordination of these behaviors has been investigated in an animal model, it has not been tested in humans., Methods: We used a novel protocol, adapted from previous work in the cat, to assess cough and swallow independently and their coordination strategies in seven healthy males (26 ± 6 years). Surface electromyograms of the submental complex and external oblique complex, spirometry, and thoracic and abdominal wall kinematics, were used to evaluate the timing of swallow, cough, and breathing as well as lung volume (LV) during these behaviors., Results: Unlike the cat, there was significant variability in the cough-swallow phase preference; however, there was a targeted LV range in which swallow occurred., Conclusion: These results give insight into the differences between the cat and human models in airway protective strategies related to the coordination of cough and swallow behaviors, allowing for better understanding of dystussia and dysphagia.

Objective: The purpose of this study was to describe ultrasound (US) changes in muscle thickness produced during automatic activation of the transversus abdominis (TrAb), internal oblique (IO), external oblique (EO), and rectus abdominis (RA), as well as the cross-sectional area (CSA) of the lumbar multifidus (LM), after 1 year of Pilates practice., Methods: A 1-year follow-up case series study with a convenience sample of 17 participants was performed. Indeed, TrAb, IO, EO, and RA thickness, as well as LM CSA changes during automatic tests were measured by US scanning before and after 1 year of Pilates practice twice per week. Furthermore, quality of life changes using the 36-Item Short Form Health Survey and US measurement comparisons of participants who practiced exercises other than Pilates were described., Results: Statistically significant changes were observed for the RA muscle thickness reduction during the active straight leg raise test (P = .007). Participants who practiced other exercises presented a larger LM CSA and IO thickness, which was statistically significant (P < .05). Statistically significant changes were not observed for the domains of the analyzed 36-Item Short Form Health Survey (P > .05). A direct moderate correlation was observed (r = 0.562, P = .019) between the TrAb thickness before and after a 1-year follow-up., Conclusions: Long-term Pilates practice may reduce the RA thickness automatic activation during active straight leg raise. Furthermore, LM CSA and IO thickness increases were observed in participants who practice other exercise types in conjunction with Pilates. Despite a moderate positive correlation observed for TrAb thickness, the quality of life did not seem to be modified after long-term Pilates practice., (Copyright © 2018. Published by Elsevier Inc.)

This study investigated by sex the effect of chest and abdominal wall mobility and respiratory muscle strength on forced vital capacity (FVC) in older adults. FVC, respiratory muscle strength, and chest and abdominal wall mobility were assessed in 154 community-dwelling older adults. As an index of the chest and abdominal wall mobility, chest (upper and lower chest) and total (upper chest, lower chest, and abdomen) scale values were measured using the breathing movement scale. Subjects with a restrictive spirometric pattern showed significantly lower chest and total scale values in both sexes, maximal inspiratory strength in women, and maximal expiratory strength in men. Chest and total scale values were significantly associated with FVC in the multiple regression analysis. The receiver operating characteristic analysis showed fair to good specificity of chest and total scale values for detecting a restrictive spirometric pattern. The results show that chest and abdominal wall mobility is closely associated with FVC in community-dwelling older adults without airflow limitation., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Purpose: Electrospun meshes may be considered as substitutes to textile polypropylene implants. We compared the host response and biomechanical properties of the rat abdominal wall following reinforcement with either polycaprolactone (PCL) modified with ureidopyrimidinone-motifs (UPy) or polypropylene mesh., Methods: First we measured the response to cyclic uniaxial load within the physiological range both dry (room temperature) and wet (body temperature). 36 rats underwent primary repair of a full-thickness abdominal wall defect with a polypropylene suture (native tissue repair), or reinforced with either UPy-PCL or ultra-light weight polypropylene mesh (n = 12/group). Sacrifice was at 7 and 42 days. Outcomes were compliance of explants, mesh dimensions, graft related complications and semi-quantitative assessment of inflammatory cell (sub) types, neovascularization and remodeling., Results: Dry UPy-PCL implants are less stiff than polypropylene, both are more compliant in wet conditions. Polypropylene loses stiffness on cyclic loading. Both implant types were well incorporated without clinically obvious degradation or herniation. Exposure rates were similar (n = 2/12) as well as mesh contraction. There was no reinforcement at low loads, while, at higher tension, polypropylene explants were much stiffer than UPy-PCL. The latter was initially weaker yet by 42 days it had a compliance similar to native abdominal wall. There were eventually more foreign body giant cells around UPy-PCL fibers yet the amount of M1 subtype macrophages was higher than in polypropylene explants. There were less neovascularization and collagen deposition., Conclusion: Abdominal wall reconstruction with electrospun UPy-PCL mesh does not compromise physiologic tissue biomechanical properties, yet provokes a vivid inflammatory reaction., (Copyright © 2017. Published by Elsevier Ltd.)

Abdominal wall hernias are one of the most common and long-standing surgical applications for biomaterials engineering. Yet, despite over 50 years of standard use of hernia repair materials, revision surgery is still required in nearly one third of patients due to hernia recurrence. To date, hernia mesh designs have focused on maximizing tensile strength to prevent structural failure of the implant. However, most recurrences occur at the biomaterial-tissue interface. There is a fundamental gap in understanding the degree to which a mechanical mismatch between hernia repair materials and host tissue contributes to failure at this interface. This review summarizes the current literature related to the anatomy and mechanics of both human and animal abdominal wall tissues, as well as the mechanical properties of many commonly-utilized hernia repair materials. The studies reviewed here reported greater compliance of the linea alba, larger strains for the intact abdominal wall, and greater stiffness for the rectus sheath and umbilical fascia when the tissues were loaded in the longitudinal direction compared to transverse. Additionally, greater stresses were observed in the linea alba when loaded in the transverse direction compared to longitudinal. Given these trends, a few recommendations can be made regarding orientation of mesh. The most compliant axis of the biomaterial should be oriented in the cranio-caudal (longitudinal) direction, and the strongest axis of the biomaterial should be oriented in the medial-lateral (transverse) direction. The human abdominal wall is also anisotropic, with anisotropy ratios as high as 8-9 reported for the human linea alba. Current biomaterial designs exhibit anisotropy ratios in the range of 1-3, and it is unclear whether an ideal ratio exists for optimal match between mesh and tissue. This is likely dependent on implantation location as the linea alba, rectus sheath, and other tissues of the abdominal wall exhibit different characteristics. Given the number of unknowns yet to be addressed by studies of the human abdominal wall, it is unlikely that any single biomaterial design currently encompasses all of the ideal features identified. More data on the mechanical properties of the abdominal wall will be needed to establish a full set of guidelines for ideal mesh mechanics including strength, compliance, anisotropy, nonlinearity and hysteresis., (Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: The aim of this review was to look at relevant data and research on the evolution of ventral hernia repair., Methods: Resources including books, research, guidelines, and online articles were reviewed to provide a concise history of and data on the evolution of ventral hernia repair., Results: The evolution of ventral hernia repair has a very long history, from the recognition of ventral hernias to its current management, with significant contributions from different authors. Advances in surgery have led to more cases of ventral hernia formation, and this has required the development of new techniques and new materials for ventral hernia management. The biocompatibility of prosthetic materials has been important in mesh development. The functional anatomy and physiology of the abdominal wall has become important in ventral hernia management. New techniques in abdominal wall closure may prevent or reduce the incidence of ventral hernia in the future., Conclusion: The management of ventral hernia is continuously evolving as it responds to new demands and new technology in surgery., (© 2017 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.)

Objective: The aim of the study was to examine abdominal wall function in patients undergoing abdominal wall reconstruction (AWR) for incisional hernia., Background: The literature on abdominal wall function in patients with incisional hernia is sparse. It has been suggested that AWR leads to improvement in function, but it is unknown whether this is specific to the abdominal wall or due to an improvement in overall physical fitness., Methods: We performed a prospective case-control study of 18 consecutive patients with large incisional hernia undergoing AWR with linea alba restoration. Truncal flexion and extension strength, hand grip strength, leg extension power, and quality of life (SF-36 and Carolinas Comfort Scale) were assessed preoperatively and 1 year postoperatively. Patients were compared with a control group of patients with an intact abdominal wall undergoing colorectal resection (n = 18). The study was registered at ClinicalTrials.gov (NCT02011048)., Results: Compared with preoperative measurements, 1-year follow-up after AWR demonstrated an increase of both truncal flexion strength (from mean 505.6 N to 572.3 N, P < 0.001) and truncal extension strength (from 556.7 to 606.0 N, P = 0.005). There was no significant change of either hand grip strength or leg extension power. After AWR, the physical component of overall quality of life improved, whereas the mental component score remained unchanged. In the control group, surgery resulted in a decrease in both truncal flexion and truncal extension., Conclusions: AWR for incisional hernia specifically improved long-term abdominal wall muscular function and quality of life.

Purpose: Paclitaxel (PTX) is currently used in combination with cisplatin for Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for the treatment of peritoneal carcinomatosis. Albumin-bound PTX is a promising new drug for HIPEC because of its easy solubility in aqueous perfusion medium and possibly because of the tendency of albumin to cross physiological barriers and accumulate in tumor tissue., Methods: We tested the feasibility of using nab-paclitaxel in rabbits treated by HIPEC for 60 min compared with the classical formulation at an equivalent PTX dose. Samples of perfusate and blood were collected at different time points and peritoneal tissues were collected at the end of perfusion. PTX concentrations were determined by HPLC. The depth of paclitaxel penetration through the peritoneal barrier was assessed by mass spectrometry imaging., Results: PTX after nab-paclitaxel treatment penetrated up to 0.63 mm in the peritoneal wall, but after CRE-paclitaxel, it was not detectable in the peritoneum. Moreover, the peritoneal concentration after nab-paclitaxel was five times that after paclitaxel classical formulation. Despite the high levels reached in the peritoneum, systemic exposure of PTX was low., Conclusions: Our results show that nab-paclitaxel penetrates into the abdominal wall better than CRE-paclitaxel, in terms of effective penetration and peritoneal tissue concentration.

Background: To provide adequate workspace between the viscera and abdominal wall, insufflation with carbon dioxide is a common practice in laparoscopic surgeries. An insufflation pressure of 15 mmHg is considered to be safe in patients, but all insufflation pressures create perioperative and postoperative physiologic effects. As a composition of viscoelastic materials, the abdominal wall should distend in a predictable manner given the pressure of the pneumoperitoneum. The purpose of this study was to elucidate the relationship between degree of abdominal distention and the insufflation pressure, with the goal of determining factors which impact the compliance of the abdominal wall., Methods: A prospective, IRB-approved study was conducted to video record the abdomens of patients undergoing insufflation prior to a laparoscopic surgery. Photo samples were taken every 5 s, and the strain of the patient's abdomen in the sagittal plane was determined, as well as the insufflator pressure (stress) at bedside. Patients were insufflated to 15 mmHg. The relationship between the stress and strain was determined in each sample, and compliance of the patient's abdominal wall was calculated. Subcutaneous fat thickness and rectus abdominus muscle thickness were obtained from computed tomography scans. Correlations between abdominal wall compliances and subcutaneous fat and muscle content were determined., Results: Twenty-five patients were evaluated. An increased fat thickness in the abdominal wall had a direct exponential relationship with abdominal wall compliance (R 2  = 0.59, p < 0.05). There was no correlation between muscle and fat thickness., Conclusion: All insufflation pressures create perioperative and postoperative complications. The compliance of patients' abdominal body walls differs, and subcutaneous fat thickness has a direct exponential relationship with abdominal wall compliance. Thus, insufflation pressures can be better tailored per the patient. Future studies are needed to demonstrate the clinical impact of varying insufflation pressures.

The aim of this study was to compare the tissue reactions to silk fibroin scaffolds in the abdominal wall, vagina, and pelvic vesico-uterine of rats. Silk fibroin scaffolds were implanted subcutaneously in the abdominal, pelvic vesico-uterine space, and under the vaginal mucosa of 16 rats. The animals were euthanized at 2, 4, 8, and 12 weeks postoperatively. Hematoxylin and eosin staining was performed to evaluate cellular infiltration, the percentage of macrophages and granulocytes inside and around the scaffolds. The amounts of M1/M2 macrophages at the interface of scaffolds and host tissue were evaluated through an immunofluorescence assay. The degree of acute inflammation was similar among the three groups, and lasted no more than 4 weeks. A faster ingrowth of fibroblasts was found in the abdominally implanted silk fibroin scaffolds, while vaginal implanted scaffolds committed a slower tissue ingrowth rate and much more macrophages infiltration than the pelvic and abdominal group. However, a significantly higher amount of M2 cells were seen in the three groups. In general, silk fibroin has nice biocompatibility in the abdominal, vagina, and pelvic tissue, eliciting healthy tissue formation, and might be a potential choice for female pelvic reconstruction. Microsc. Res. Tech. 80:291-297, 2017. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

The aim of this study is to characterize the passive mechanical behaviour of abdominal wall in vivo in an animal model using only external cameras and numerical analysis. The main objective lies in defining a methodology that provides in vivo information of a specific patient without altering mechanical properties. It is demonstrated in the mechanical study of abdomen for hernia purposes. Mechanical tests consisted on pneumoperitoneum tests performed on New Zealand rabbits, where inner pressure was varied from 0mmHg to 12mmHg. Changes in the external abdominal surface were recorded and several points were tracked. Based on their coordinates we reconstructed a 3D finite element model of the abdominal wall, considering an incompressible hyperelastic material model defined by two parameters. The spatial distributions of these parameters (shear modulus and non linear parameter) were calculated by inverse analysis, using two different types of regularization: Total Variation Diminishing (TVD) and Tikhonov (H 1 ). After solving the inverse problem, the distribution of the material parameters were obtained along the abdominal surface. Accuracy of the results was evaluated for the last level of pressure. Results revealed a higher value of the shear modulus in a wide stripe along the craneo-caudal direction, associated with the presence of linea alba in conjunction with fascias and rectus abdominis. Non linear parameter distribution was smoother and the location of higher values varied with the regularization type. Both regularizations proved to yield in an accurate predicted displacement field, but H 1 obtained a smoother material parameter distribution while TVD included some discontinuities. The methodology here presented was able to characterize in vivo the passive non linear mechanical response of the abdominal wall., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

A variety of techniques have been applied to generate tissue engineered constructs, where cells are combined with degradable scaffolds followed by a period of in vitro culture or direct implantation. In the current study, a cellularized scaffold was generated by concurrent deposition of electrospun biodegradable elastomer (poly(ester urethane)urea, PEUU) and electrosprayed culture medium + skeletal muscle-derived stem cells (MDSCs) or electrosprayed culture medium alone as a control. MDSCs were obtained from green fluorescent protein (GFP) transgenic rats. The created scaffolds were implanted into allogenic strain-matched rats to replace a full thickness abdominal wall defect. Both control and MDSC-integrated scaffolds showed extensive cellular infiltration at 4 and 8 wk. The number of blood vessels was higher, the area of residual scaffold was lower, number of multinucleated giant cells was lower and area of connective tissue was lower in MDSC-integrated scaffolds (p < 0.05). GFP + cells co-stained positive for VEGF. Bi-axial mechanical properties of the MDSC-microintegrated constructs better approximated the anisotropic behavior of the native abdominal wall. GFP + cells were observed throughout the scaffold at ∼5% of the cell population at 4 and 8 wk. RNA expression at 4 wk showed higher expression of early myogenic marker Pax7, and b-FGF in the MDSC group. Also, higher expression of myogenin and VEGF were seen in the MDSC group at both 4 and 8 wk time points. The paracrine effect of donor cells on host cells likely contributed to the differences found in vivo between the groups. This approach for the rapid creation of highly-cellularized constructs with soft tissue like mechanics offers an attractive methodology to impart cell-derived bioactivity into scaffolds providing mechanical support during the healing process and might find application in a variety of settings., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In this study, we report about a patient with extra-uterine endometriosis (EM) in the abdominal wall muscle with evident metaplasia based on the abundant alpha smooth muscle actin (ASMA)-expressing myofibroblasts. Laparotomy excision of the abdominal wall EM was done following ultrasonographic evidence of a hypodense swelling in the right rectus abdominis, which was confirmed by MRI. Immunohistochemistry staining for ASMA and collagen I was done, with the results confirming that endometriotic stromal cells expressed both. Anterior abdominal wall endometriosis was suspected because of the patient's history of recurrent EM combined with the cyclic nature of symptoms. MRI is useful in determining the extent of the disease. In case of persisting symptoms even under hormonal treatment, surgical excision is mandatory. The expression of both ASMA and collagen I in and around EM lesions supports the notion of the metaplastic process in the course of disease development., (© 2016 S. Karger AG, Basel.)

Background: Thoracoabdominal asynchrony is often adopted to discriminate respiratory diseases in clinics. Conventionally, Lissajous figure analysis is the most frequently used estimation of the phase difference in thoracoabdominal asynchrony. However, the temporal resolution of the produced results is low and the estimation error increases when the signals are not sinusoidal. Other previous studies have reported time-domain procedures with the use of band-pass filters for phase-angle estimation. Nevertheless, the band-pass filters need calibration for phase delay elimination., Methods: To improve the estimation, we propose a novel method (named as instantaneous phase difference) that is based on complementary ensemble empirical mode decomposition for estimating the instantaneous phase relation between measured thoracic wall movement and abdominal wall movement. To validate the proposed method, experiments on simulated time series and human-subject respiratory data with two breathing types (i.e., thoracic breathing and abdominal breathing) were conducted. Latest version of Lissajous figure analysis and automatic phase estimation procedure were compared., Results: The simulation results show that the standard deviations of the proposed method were lower than those of two other conventional methods. The proposed method performed more accurately than the two conventional methods. For the human-subject respiratory data, the results of the proposed method are in line with those in the literature, and the correlation analysis result reveals that they were positively correlated with the results generated by the two conventional methods. Furthermore, the standard deviation of the proposed method was also the smallest., Conclusions: To summarize, this study proposes a novel method for estimating instantaneous phase differences. According to the findings from both the simulation and human-subject data, our approach was demonstrated to be effective. The method offers the following advantages: (1) improves the temporal resolution, (2) does not introduce a phase delay, (3) works with non-sinusoidal signals, (4) provides quantitative phase estimation without estimating the embedded frequency of breathing signals, and (5) works without calibrated measurements. The results demonstrate a higher temporal resolution of the phase difference estimation for the evaluation of thoracoabdominal asynchrony.

There are few studies on the stress-stretch behaviour of human linea alba, yet understanding the mechanics of this tissue is important for developing better methods of abdominal wound closure. Published data focuses mainly on porcine linea alba and for human tissue there are conflicting results and no bi-axial data available. This variability is likely due to challenges with the physical dimensions of the tissue and differences in experimental methodology. This study focussed on the tensile mechanical characterisation of the human linea alba using uniaxial and equi-load biaxial testing performed using image-based strain measurement methods. Thirteen freshly frozen human cadaveric abdominal walls were obtained and used to prepare 7 samples in both the transverse and longitudinal directions for uniaxial testing, and 13 square samples for bi-axial testing. The results showed significant anisotropy and for the equi-load biaxial tests the deformation was heavily biased in the longitudinal direction. In comparison with similar tests on porcine tissue from a previous study, it was found that the response of porcine linea alba to uniaxial loading is similar to that of human linea alba, with no statistically significant differences observed. Under biaxial loading human and porcine linea showed no statistical significance in the difference between their means in the transverse direction. However, a significant difference was observed in the longitudinal direction, and further study of the respective tissue structures is needed to better understand this result. These results provide the first data on the biaxial tensile properties of human linea alba and can aid in an improved assessment of wound closure mechanics., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The linea alba is a complex structure commonly involved in hernia formation. Knowledge of its mechanical behavior is essential to design suitable meshes and reduce the risk of recurrence. The aim of this study was to investigate the relationships between the mechanical properties of the linea alba and the organization of collagen and elastin fibers. For that purpose, longitudinal and transversal samples were removed from four porcine and three human linea alba, to perform tensile tests under a biphotonic confocal microscope, in each direction. Microscopic observation revealed a tissue composed of two layers, made of transversal collagen fibers in the dorsal side and oblique collagen fibers in the ventral side. This particular architecture led to an anisotropic mechanical behavior, with higher stress in the transversal direction. During loading, oblique fibers of the ventral layer reoriented toward the tensile axis in both directions, while fibers of the dorsal layer remained in the transversal direction. This rotation of oblique fibers progressively increased the stiffness of the tissue and induced a non-linear stress-stretch relation. Elastin fibers formed a layer covering the collagen fibers and followed their movement, suggesting that they ensure their elastic recoil. All of these results demonstrated the strong relationships between the microstructure and the mechanical behavior of the linea alba., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Previous studies showed that chlorogenic acid (CGA) accelerates wound healing via its antioxidant activity. We aimed to investigate the effect of CGA in an experimental epigastric abdominal skin flap model in nondiabetic and diabetic rats. Rats were firstly divided into 2 groups: nondiabetic and diabetic. Diabetes was induced by streptozotocin. Then, 4 subgroups were created for each group: vehicle as well as 0.2 mg/0.5 mL, 1 mg/0.5 mL, and 5 mg/0.5 mL CGA treatments. Right epigastric artery-based abdominal skin flaps were elevated and sutured back into their original position. Chlorogenic acid or vehicle was injected once into the femoral arteries by leaving the epigastric artery as the single artery feeding the flaps during the injection. On postoperative day 7, flap survivals were evaluated, and the rats were killed. Distal flap tissues were collected for histopathological and biochemical assays. Chlorogenic acid showed greater flap survival in both nondiabetic and diabetic rats. Capillary density was increased, and necrosis was reduced in the CGA-treated rats. Chlorogenic acid decreased malondialdehyde levels as well as increased reduced glutathione and superoxide dismutase levels in the flap tissues. This study showed that CGA significantly improved flap survival by its antioxidant activities with intra-arterial local injections.

The performance of hernia treatment could benefit from more extensive knowledge of the mechanical behavior of the abdominal wall in a healthy state. To supply this knowledge, the antero-lateral abdominal wall was characterized in vivo on 11 healthy volunteers during 4 activities: rest, pullback loading, abdominal breathing and the "Valsalva maneuver". The elasticity of the abdominal muscles (rectus abdominis, obliquus externus, obliquus internus and transversus abdominis) was assessed using ultrasound shear wave elastography. In addition, the abdomen was subjected to a low external load at three locations: on the midline (linea alba), on the rectus abdominis region and on lateral muscles region in order to evaluate the local stiffness of the abdomen, at rest and during "Valsalva maneuver". The results showed that the "Valsalva maneuver" leads to a statistically significant increase of the muscle shear modulus compared to the other activities. This study also showed that the local stiffness of the abdomen was related to the activity. At rest, a significant difference has been observed between the anterior (0.5N/mm) and the lateral abdomen locations (1N/mm). Then, during the Valsalva maneuver, the local stiffness values were similar for all locations (ranging from 1.6 to 2.2N/mm). This work focuses on the in vivo characterization of the mechanical response of the human abdominal wall and abdomen during several activities. In the future, this protocol could be helpful for investigation on herniated patients., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Study Design Cross-sectional repeated measures. Background Rehabilitation of diastasis rectus abdominis (DRA) generally aims to reduce the inter-rectus distance (IRD). We tested the hypothesis that activation of the transversus abdominis (TrA) before a curl-up would reduce IRD narrowing, with less linea alba (LA) distortion/deformation, which may allow better force transfer between sides of the abdominal wall. Objectives This study investigated behavior of the LA and IRD during curl-ups performed naturally and with preactivation of the TrA. Methods Curl-ups were performed by 26 women with DRA and 17 healthy control participants using a natural strategy (automatic curl-up) and with TrA preactivation (TrA curl-up). Ultrasound images were recorded at 2 points above the umbilicus (U point and UX point). Ultrasound measures of IRD and a novel measure of LA distortion (distortion index: average deviation of the LA from the shortest path between the recti) were compared between 3 tasks (rest, automatic curl-up, TrA curl-up), between groups, and between measurement points (analysis of variance). Results Automatic curl-up by women with DRA narrowed the IRD from resting values (mean U-point between-task difference, -1.19 cm; 95% confidence interval [CI]: -1.45, -0.93; P<.001 and mean UX-point between-task difference, -0.51 cm; 95% CI: -0.69, -0.34; P<.001), but LA distortion increased (mean U-point between-task difference, 0.018; 95% CI: 0.0003, 0.041; P = .046 and mean UX-point between-task difference, 0.025; 95% CI: 0.004, 0.045; P = .02). Although TrA curl-up induced no narrowing or less IRD narrowing than automatic curl-up (mean U-point difference between TrA curl-up versus rest, -0.56 cm; 95% CI: -0.82, -0.31; P<.001 and mean UX-point between-task difference, 0.02 cm; 95% CI: -0.22, 0.19; P = .86), LA distortion was less (mean U-point between-task difference, -0.025; 95% CI: -0.037, -0.012; P<.001 and mean UX-point between-task difference, -0.021; 95% CI: -0.038, -0.005; P = .01). Inter-rectus distance and the distortion index did not change from rest or differ between tasks for controls (P≥.55). Conclusion Narrowing of the IRD during automatic curl-up in DRA distorts the LA. The distortion index requires further validation, but findings imply that less IRD narrowing with TrA preactivation might improve force transfer between sides of the abdomen. The clinical implication is that reduced IRD narrowing by TrA contraction, which has been discouraged, may positively impact abdominal mechanics. J Orthop Sports Phys Ther 2016;46(7):580-589. doi:10.2519/jospt.2016.6536.

The present work aims to assess, via numerical modeling, the global passive mechanical behavior of the healthy abdominal wall under the action of pressures that characterize different daily tasks and physiological functions. The evaluation of a normal range of intra-abdominal pressure (IAP) during activities of daily living is fundamental because pressure alterations can cause several adverse effects. At this purpose, a finite element model is developed from literature histomorphometric data and from diagnostic images of Computed Tomography (CT), detailing the different anatomical regions. Numerical simulations cover an IAP up to the physiological limit of 171 (0.0223MPa) mmHg reached while jumping. Numerical results are in agreement with evidences on physiological abdomens when evaluating the local deformations along the craniocaudal direction, the transversal load forces in different regions and the increase of the abdominal area at a IAP of 12mmHg. The developed model can be upgraded for the investigation of the abdominal hernia repair and the assessment of prostheses mechanical compatibility, correlating stiffness and tensile strength of the abdominal tissues with those of surgical meshes., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: The relationship between activation of the stabilizing muscles of the lumbopelvic region during the Active Straight Leg Raise test and pelvic girdle pain remains unknown. Therefore, the aim was to examine automatic contractions in relation to pre-activation in the muscles of the pelvic floor and the lower lateral abdominal wall during leg lifts, performed as the Active Straight Leg Raise test, in women with and without persistent postpartum pelvic girdle pain., Methods: Sixteen women with pelvic girdle pain and eleven pain-free women performed contralateral and ipsilateral leg lifts, while surface electromyographic activity was recorded from the pelvic floor and unilaterally from the lower lateral abdominal wall. As participants performed leg lifts onset time was calculated as the time from increased muscle activity to leg lift initiation., Findings: No significant differences were observed between the groups during the contralateral leg lift. During the subsequent ipsilateral leg lift, pre-activation in the pelvic floor muscles was observed in 36% of women with pelvic girdle pain and in 91% of pain-free women (P=0.01). Compared to pain-free women, women with pelvic girdle pain also showed significantly later onset time in both the pelvic floor muscles (P=0.01) and the muscles of the lower lateral abdominal wall (P<0.01)., Interpretation: We suggest that disturbed motor activation patterns influence women's ability to stabilize the pelvis during leg lifts. This could be linked to provocation of pain during repeated movements., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Currently, autologous breast reconstruction with a free tissue transfer from the lower abdomen is considered to be a safe method that provides a stable long-term solution. The DIEP-flap and the ms-2-TRAM-flap reconstructions have helped reduce donor site morbidity. In order to assess the potential differences between these techniques, we carried out myosonographic evaluations that assessed the muscle dynamics pre- and post-operatively. In addition to investigating the properties of the rectus abdominis muscle post-operatively, this prospective study also allowed us to analyse the muscle preoperatively and to investigate the prospects for harvesting a DIEP-flap as opposed to a TRAM-flap., Materials and Methods: Sixty patients underwent breast reconstruction with 71 (11 bilateral) free abdominal wall flaps (DIEP-: n = 48; ms-2-TRAM-flap: n = 23). Myosonographic examinations were performed preoperatively and at 3 and 6 months post-operatively. The thickness of the muscle at relaxation and maximum contraction and the difference between the muscle thickness measured at the two states were measured. A general-linear-model (GLM) was used for statistical analysis. The main variable was the surgical method, and the co-variables included BMI and patient age. The decision on whether to harvest a DIEP- or ms-2-TRAM-flap was made intra-operatively and based on the dominant perforator., Results: It shows that the patients who underwent breast reconstruction with a DIEP-flap had significantly better muscle function (p < 0.05) in the follow-up. In addition, the analysis revealed that better muscle function before surgery made it more likely that a patient would undergo a DIEP-flap-reconstruction successfully. Patient age also had a highly significant effect on muscle recovery (p < 0.0005)., Conclusions: This prospective study used a dynamic ultrasound evaluation of the abdominal wall and showed that the DIEP-flap significantly reduces donor site morbidity compared to the ms-2-TRAM-flap. The study also showed that good preoperative muscle function might increase the probability of surgeons performing a DIEP-flap reconstruction., (Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Objective: To determine the immediate effect of hold-relax (HR) stretching of the iliopsoas muscle on pain, transversus abdominis (TrA) activation capacity, lumbar stability level, lumbar lordosis angle and iliopsoas muscle length in chronic non-specific low back pain (CNSLBP) with lumbar hyperlordosis., Material and Method: Participants aged from 30-55 years with CNSLBP with lumbar hyperlordosis were divided in two groups: (Group 1) Intervention group received 10-second isometric contraction ofthe iliopsoas muscle (HR), 10-second rest, 20-second static stretch, 5 repetitions. (Group 2) control group received 15 minutes resting in supine lying. The visual analog scale, prone test with the pressure biofeedback unit, modified isometric stability test, aflexible ruler and modified Thomas test were usedforpre- and post-test. Two-way ANOVA was used for within and between-group comparisons., Results: The present study consisted of 20 participants. Significant differences were found in pain, TrA activation capacity, lumbar lordosis angle and iliopsoas muscle length between intervention and control groups and between pre- and post-test for intervention group (p<0.05). Lumbar stability level showed no significant difference in within and between-group comparisons., Conclusion: The HR of the iliopsoas muscle reduced pain and lumbar lordosis angle, enhanced TrA activation, and increased length of hip flexor in CNSLBP with lumbar hyperlordosis.

When the abdomen in quadriplegic subjects is given a passive mechanical support, the expansion of the lower rib cage during inspiration is greater and the inward displacement of the upper rib cage is smaller. These changes have traditionally been attributed to an increase in the appositional force of the diaphragm, but the mechanisms have not been assessed. In this study, the inspiratory intercostal muscles in all interspaces were severed in anesthetized dogs, so that the diaphragm was the only muscle active during inspiration, and the displacements of the ribs 10 and 5 and the changes in pleural and abdominal pressure were measured during unimpeded breathing and during breathing with a plate applied on the ventral abdominal wall. In addition, external forces were applied to the 10th rib pair in the cranial and lateral directions, and the rib trajectories thus obtained were used as the basis for a vector analysis to estimate the relative contributions of the insertional and appositional forces to the rib 10 displacements during breathing. Application of the abdominal plate caused a marked increase in the inspiratory cranial and outward displacement of rib 10 and a decrease in the inspiratory caudal displacement of rib 5. Analysis of the results showed, however, that 1) the insertional and appositional forces contributed nearly equally to the increased inspiratory displacement of rib 10 and 2) the decrease in the expiratory displacement of rib 5 was the result of both the greater displacement of the lower ribs and the decrease in pleural pressure., (Copyright © 2015 the American Physiological Society.)

Objective: Heat is a sign and symptom of surgical wound infection in wound assessment criteria but there is currently no diagnostic tool being used in clinical practice to assess the skin temperature of surgical wounds. Using thermal imaging, the objective of this study was to map the temperature of the healing surgical wound and to provide confirmatory data of: a) optimum IR imaging distance from skin temperature target field of view (FOV) b) body composition effects on abdominal skin surface temperature readings c) thermal mapping characteristics of infected versus non-infected wounds post stoma-closure., Method: The abdominal skin surface temperature of healthy, afebrile subjects was measured under controlled, ambient conditions in a small (240cm x 320cm) clinical room. Subject standing positions were 30cm, 60cm and 100cm from the IR camera. Abdominal skin surface temperature and thermal imaging maps were acquired in a population of surgical patients before and after closure of enterostoma., Results: Subjects (30) aged 19-52 (median=29) years were recruited. At a distance of 100cm, each of nine anatomical regions showed a decrease in mean temperature as BMI increased. Subjects with BMI >25 had lower mean abdominal temperatures. Statistically significant differences were observed for right hypochondrium (p=0.022), left lumbar region (p=0.009), right lumbar region (p=0.010) and the umbilical region (p=0.021). Half of patients (5/10) developed surgical wound infection., Conclusion: Within the operating distances investigated, no significant effect on abdominal temperature readings was observed. With increasing BMI, lower abdominal temperatures were noted. The thermal pattern of abdominal surgical wounds reveals some differences between the healing and infected wound. Healing wounds showed changes in the thermal 'map'; an increase in temperature on the first post-operative day, and 'warming' over the subsequent five days. 'Cold spots' emerged on the thermogram of the surgical wounds which subsequently were shown to be infected. Within the setting of a clinical environment, distances up to 100cm did not significantly alter skin temperature readings within the FOV. There is a suggestion that body composition influences skin temperature. Infected surgical wounds appear 'colder' than healing wounds., Declaration of Interest: The authors have no conflict or interest. The work was supported by a grant from the SingHealth Foundation.

Objective: The study purpose was to evaluate the associations between patient characteristics or surgical site classifications and the histologic remodeling scores of biologic meshes biopsied from abdominal soft tissue repair sites in the first attempt to generate a multivariable risk-prediction model of nonconstructive remodeling., Background: Host characteristics and surgical site assessments may predict remodeling degree for biologic meshes used to reinforce abdominal tissue repair sites., Methods: Biologic meshes were biopsied from the abdominal tissue repair sites of n = 40 patients during an abdominal reexploration, stained with hematoxylin and eosin, and evaluated according to a semi-quantitative scoring system for remodeling characteristics (cell types, cell infiltration, extracellular matrix deposition, scaffold degradation, fibrous encapsulation, and neovascularization) and a mean composite score. Biopsies were stained with Sirius Red and Fast Green and analyzed to determine the collagen I:III ratio. On the basis of univariate analyses between subject clinical characteristics or surgical site classification and the histologic remodeling scores, cohort variables were selected for multivariable regression models using P ≤ 0.200., Results: The model selection process for cell infiltration score yielded 2 variables: age at mesh implantation and mesh classification (C statistic = 0.989). For the mean composite score, the model selection process yielded 2 variables: age at mesh implantation and mesh classification (r = 0.449)., Conclusions: These preliminary results constitute the first steps in generating a risk-prediction model that predicts the patients and clinical circumstances most likely to experience nonconstructive remodeling of abdominal tissue repair sites with biologic mesh reinforcement.