Defect Width Research Articles

Arthroscopic defect size measurement in osteochondral lesions of the talus underestimates the exact defect size and size measurement with arthro-MRI (MR-A) and high-resolution flat-panel CT-arthro imaging (FPCT-A).

The size of osteochondral lesions of the talus (OLTs) is highly relevant for their treatment. In addition to intraoperative measurement of defect size, preoperative planning by means of magnetic resonance imaging (MRI) or computed tomography (CT) is crucial. Four defects of different sizes and depths were created on the talar joint surface in 14 cadaver feet. All defects were evaluated, both arthroscopically and via arthrotomy with a probe. Arthro-MRI (MR-A) and high-resolution flat-panel CT arthro scans (FPCT-A) were acquired. Length, width, and depth were measured for every defect and the defect volume was calculated. To determine the exact defect size, each talar defect was filled with plastic pellets to form a cast and the casts were scanned using FPCT to create a 3D multiplanar reconstruction data set. Finally, the surgically measured values were compared with the radiological values and the exact defect size. Overall, the surgically measured values (both arthroscopic and open) underestimated the exact defect size (p < 0.05). Arthroscopically determined defect length and width showed the largest deviation (p < 0.05) and underestimated the size in comparison with MR-A and FPCT-A. The FPCT-A measurements demonstrated higher correlation with both the arthroscopic and open surgical measurements than did the MR-A measurements (p < 0.05). The exact defect size is underestimated on intraoperative measurement, in both arthroscopic and open approaches. Arthroscopic defect size measurement underestimates defect size in comparison with MR-A and FPCT-A. FPCT-A was shown to be a reliable imaging technique that allows free image reconstruction in every plane and could be considered as the new reference standard for preoperative evaluation of defect size in OLT.

Comparative evaluation of demineralized freeze-dried bone allograft with and without concentrated growth factor membrane in the treatment of periodontal intrabony defects: a randomized controlled clinical trial.

The current study's aim was to evaluate and compare demineralized freeze-dried bone allograft (DFDBA) with and without concentrated growth factor (CGF) membrane in the treatment of periodontal intrabony defects on both a clinical and radiographic level. 30 stage III grade B periodontitis patients with bilateral intrabony defects were involved in the split mouth randomized controlled trial, and they received either DFDBA alone (control group) or DFDBA plus CGF membrane treatment (test group). At baseline and 6 and 12months, the gingival index (GI), plaque index (PI), probing pocket depth (PPD), clinical attachment level (CAL), and gingival recession (GR) were assessed, whereas cone beam computed tomography was used to assess the bone defect height (BDH), vertical bone loss (VBL), bone defect depth (BDD), mesio-distal bone defect width (MDBDW), bucco-lingual bone defect width (BLBDW), and bone defect volume (CBCT) at baseline and 12months. The radiographic measures BDH, BDD, MDBDW, BLBDW, and BDV in the test group likewise showed a higher reduction in PPD and gain in CAL than the control group. The results of the intergroup comparison showed that the test group had statistically significant differences in BDH, BDD, and MDBDW. The data show that the test group achieved better results, with greater reductions in PPD, gains in CAL, and decreases in BDH, BDD, MDBDW, BLBDW, and BDV. The use of concentrated growth factor in conjunction with demineralized freeze-dried bone allograft may be suggested for the treatment of periodontal intrabony defects.

Dynamic Modeling and Simulation Analysis of Inter-Shaft Bearings with Local Defects Considering Elasto-Hydrodynamic Lubrication

As an important component of large engines, inter-shaft bearing is easily damaged due to its poor working conditions. By analyzing the time–frequency distribution rules of fault signals and the evolution law of micro-faults, the bearing failure mechanism can be revealed, and the bearing failure can be monitored in real time and prevented in advance. For the purpose of studying the mechanism of inter-shaft bearing faults, a 4-DOF (degree of freedom) dynamic model of inter-shaft bearing with local defects considering elasto-hydrodynamic lubrication (EHL) is proposed. Based on the established dynamic model, the impact characteristics and distribution rules of the fault signals of the bearing are accurately simulated, and the evolution law of the micro-faults is also analyzed. The effects of different speeds, loads and defect widths on maximum value (MV), absolute mean value (AMV), effective value (EV), amplitude of square root (AST), kurtosis factor (KF), impulse factor (IF), peak factor (PF) and shape factor (SF) are obtained. The findings show that the vibration amplitude of the bearing increases with the increase in defect size, and the faults are easier to diagnose accordingly. At the same time, PF, KF and IF are very sensitive to the initial failure of bearings. With the development of faults, the overall trend of AMV, AST and EV are relatively stable. The PF is sensitive to the change of rotating speeds and defect widths. The SF is insensitive to the change of rotating speeds, loads and defect widths. This lays a foundation for the research of monitoring and diagnosis methods of aeroengine inter-shaft bearing fault.

Posterior component separation with TAR: lessons learned from our first consecutive 52 cases.

Patients with complex incisional hernia (IH) is a growing and challenging category that surgeons are facing in daily practice and represent indeed a technical challenge for most of them. The posterior component separation with TAR (PCS-TAR) has become the procedure of choice to repair most complex abdominal wall defects, including those with loss of domain, subxiphoid, subcostal, parastomal or after trauma and sepsis treated initially with "open abdomen" and in those scenarios in which the fascia closure was not performed to avoid an abdominal compartment syndrome. Most recent studies showed that the PCS-TAR represents a valid procedure in recurrent IH. The purpose of our study is to evaluate the reproducibility of the PCS-TAR, describing our experience, our surgical technique and the rate of postoperative complications and recurrences in a cohort of consecutive patients. 52 consecutive patients with complex IH, who underwent PCS-TAR at "Betania Hospital and Ospedale del Mare Hospital" in Naples between May 2014 and November 2019 were identified from a prospectively maintained database and reviewed retrospectively. There were 36 males (69%) and 16 females (31%) with a mean age of 57.88 (range 39-76) and Body mass index (BMI kg/m2) of 31.2 (24-45). More than half of patients (58%) were active smokers. Mean defect width was 13.6cm (range 6-30) and mean defect area was about 267.9cm2. Mean operative time was 228min. Posterior fascial closure was reached in all cases, while anterior fascial closure only in 29 cases (56%). Mean hospital stay was 5.7days. 27% of patients developed minor complications (Clavien-Dindo grade I-II) and one case (1.9%) major complication (Clavien-Dindo III). Seroma was registered in 23% of cases. SSI was reported to be 3.8% with no deep wound infection. Recurrence rate was 1.9% in a mean follow-up of 28months. In Univariate analysis Bio-A surface > 600cm2 and drain removal at discharge were significantly associated with major complications, while in a multivariate analysis only Bio-A surface > 600cm2 was related. Considering univariate analysis for recurrences, number of drains, SSO, Clavien-Dindo score > 2 and defect area were significantly associated with recurrence, while in a multivariate analysis no variables were related. PCS-TAR is an indispensable tool in managing complex ventral hernias associated with a low rate of SSO and recurrence. Tobacco use, obesity and comorbidities cannot be considered absolute contraindications to PCS-TAR. Peri and postoperative management of complications and drainages have an impact on short term outcomes. Based on these outcomes, posterior component separation with transversus abdominis release has become our method of choice for the management of patients with complex ventral hernia requiring open hernia repair in selected patients.

Nondestructive analysis of rolling contact fatigue cracks using induced scanning thermography.

Rolling contact fatigue (RCF) produced by wheel-rail interaction is now considered to be a critical factor that causes failure. Throughout this work, induced scanning thermography (IST) for detecting RCF defects at different depths is investigated. The original thermal sequences could not utilize the features at the heat dissipation stage; thus, a data reconstruction method, including principal component analysis (PCA) and Tucker factorization, was employed to extract the spatial and time patterns. In addition, detectability was evaluated across a range of speed studies. The Tucker-PCA combination algorithms obtained defects with improved quality, showing a clear boundary over the velocity range of 1-4km/h, which dramatically suppressed background noise. A unique gradient response characteristic in the cooling phase was summarized and utilized through experimental verification in order to recognize defect width.

Analysis of the Effectiveness of Removing Surface Defects by Brushing

The paper presents the results of a study on the effectiveness of removing surface defects by brushing. Damage to machine components usually begins on their surface or in the surface layer area. This determines the development of methods, conditions, and process parameters that will positively affect the stereometric and physical properties of the surface layer. Experiments were conducted in which surface defects were generated on a specially designed test stand. By controlling the load and speed of the defect generator it was possible to affect the geometry, depth, and width of the surface defect. A FEM simulation of the brushing treatment was carried out in order to determine the effect of fibers passing through a surface defect in the form of a groove with a small depth and width. It was shown that for certain conditions of brushing treatment, surface defects could be removed effectively. Moreover, the microhardness of the surface layer after the brushing process was analyzed. Changes in microhardness due to brushing reached up to 50 μm for EN AW-2024 aluminum alloy and up to 150 μm for AZ91HP magnesium alloy. The results demonstrated that brushing was an effective method for strengthening the surface layer and that the value of strengthening in the area of defects depended on the effectiveness of their removal.

Effect of defect geometries upon burst capacity of composite repaired pipe

Oil and gas pipelines have been used all around the world and becoming more crucial in our daily life. These pipelines are subjected to corrosion and one of the most effective ways for repairing them is using composite wrap. Nevertheless, there are still issues and challenges to be overcome for a more effective design of composite repaired pipelines, which could be further investigated. Defect geometries (depth, width and length) on pipelines can affect the burst pressure that can be sustained by the pipelines. Yet, current standards and practices only account for defect depth in determining minimum thickness of composite wrap required in repairing defective pipelines without considering defect width and length. Thus, the aim of this study is to analyze the effect of defect length and width of composite repaired pipe upon its burst capacity using finite element analysis. A finite element model was created and validated followed by parametric study on the effect of combination defect length and width. For parametric study, a total of seven composite repaired pipe models were created and analyzed. Results showed that as the defect dimension of combinations defect geometries increases, the burst pressure of the composite repaired pipe decreases. The burst pressure between the smallest and largest defect is 31.09% which shows a significant difference. In conclusion, defect geometries are proven greatly affect the burst pressure of the composite repaired pipe and the findings can be used for future studies, in particular to refine the design of the composite pipeline repair practice.

Quantitative study of the defects of ferromagnetic materials using the magnetic charge model and particle swarm optimization algorithm

Local defects in components are an important factor responsible for causing damage to steel structures. Hence, metal magnetic memory (MMM) has been used to investigate this issue in recent years. MMM can detect defects based on variations in the self-magnetic leakage of ferromagnetic materials. However, there have been problems of difficulty in quantifying the theoretical parameters of the magnetic charge model and the single characterization of magnetic feature parameters, when using MMM for quantitative analysis of defects. Therefore, the particle swarm optimization (PSO) algorithm was introduced to quicky and accurately quantify the parameters of the magnetic charge model. Theoretical values were compared with experimental data to verify the accuracy of the proposed method. Then, the defect information (defect width and defect depth) was changed and the variation patterns of the magnetic signal and characteristic parameters were analyzed. Finally, the weight of each characteristic parameter was calculated using the entropy value method. A theoretical formula to comprehensively describe defects using multi-feature parameters was proposed. The results show that the theoretical values calculated based on the parameter identification of the PSO algorithm well agreed with the experimental data. Moreover, the proposed formula well described the relationship between the defect width and characteristic parameters. This study is expected to provide a basis for improving the quantitative analysis of MMM.

Umbilical Laparoscopic Transabdominal Preperitoneal Repair for Medium-Sized Umbilical Hernia in Overweight and Obese Patients

INTRODUCTION: Despite high prevalence of umbilical hernia, an open anterior approach is still frequently performed. Moreover, suture repair is still routinely applied in cases of small umbilical hernia. However, mesh use may lead to more frequent surgical site infection, especially in obese patients. Some of these limitations may be reconciled by transabdominal-preperitoneal repair (TAPP). The aim of this study was to analyze feasibility, safety and efficacy of umbilical TAPP (u-TAPP). METHODS: A prospective study of early and mid-term outcomes was conducted for all umbilical hernia repair performed in overweight and obese patients. An analysis included 36 patients undergoing elective surgery for primary umbilical hernia between March 2019 and November 2021. The intra- and postoperative data were recorded. All patients reported the outcomes 1 and 3 months after the procedure. RESULTS: The mean width of defect was 26 mm. The operation time was 93.2 ± 22.3 minutes. An area of synthetic mesh in u-TAPP was 164.2 cm2. Median mesh size was 10×15 cm. After 30-day and 3-month follow-up, there was no recurrence or significant postoperative pain. The patients declared their overall satisfaction and quality of life as good or excellent. CONCLUSION: TAPP technique in umbilical hernia repair allows for placement of a large mesh and fulfills current recommendations, especially for patients with additional risk factors, such as obesity or coexistence of diastasis recti. TAPP allows a mesh to be introduced into the preperitoneal space, allowing to avoid direct contact between mesh and intestines. Laparoscopic umbilical TAPP is feasible and safe, but the operation time is longer than with open methods.

P-131 SHORT TERM RESULTS OF PREOPERATIVE TOXIN BOTULINUM A IN PREPARATION FOR ABDOMINAL WALL RECONSTRUCTION

Abstract Aim to report short term outcomes of preoperative toxin botulinum A (TBA) in preparation for abdominal wall reconstruction (AWR). Material and Methods Patient with a hernia width&amp;gt;10cm and/or loss of domain who underwent elective AWR from April 2021 through March 2022 were included. All patients received ultrasound-guided administration of 300 units of TBA prior the surgery. Outcomes of interest included: changes in hernia dimensions and CT-Scan volumetric measurements after treatment, rates of complete fascial closure, postoperative intraabdominal hypertension, unplanned readmission and hernia recurrence. Results Fifteen patients were included (53% males; mean age 61years, mean body mass index 28.9kg/m2). Median hernia width decreased by 2cm (before 15cm [IQR 14–18.5], after 13cm [IQR 10.3–15]; p=0.002) and median abdominal cavity volume increased by 1.4L (before 4.8L [IQR 3.8–11.1], after 6.2L [4.2–9.2]; p=0.594). Thickness of lateral abdominal wall muscles decreased (before 2cm [IQR 1.6–3], after 1.1cm [IQR 1–1.3]; p=0.008 and the Tanaka Index decreased (12% [IQR 3.6–24.2] and 5% [IQR 1.4–16.8]; p=0.066) Complete fascial closure was achieved in 13cases(87%). Three patients did not require component separation. Mean endotracheal pressure was 19mmHg. There were no intraabdominal hypertension. At a median 9months follow-up [range 6.2–11.5] wound morbidity rate was 20%(N=3), N=1 recurrence, N=1 unplanned readmission. Conclusions TBA promotes changes to the lateral abdominal wall with decrease on defect width and thickness of lateral muscles and increase in cavity volume and Tanaka index. Randomized clinical trials are needed to determine the clinical implication of preoperative TBA in preparation for AWR.

OC-011 PREOPERATIVE BOTULINUM TOXIN A INJECTION CAN ACHIEVE SIMILAR OUTCOMES AS COMPONENT SEPARATION TECHNIQUES IN COMPLEX ABDOMINAL WALL RECONSTRUCTION WITH DECREASED MORBIDITY– A PROPENSITY-SCORED MATCHED STUDY

Abstract Aims CST have been effective in closing large defects but at the sacrifice of fascia and muscle and often increasing complication rates. Preoperative BTA has emerged as an adjunct to aid in fascial closure. Little data exist comparing pre-operative BTA versus CST, and our aim was to do so in a matched study. Materials &amp; Methods A 3:1 propensity matched study of patients from a single institution hernia database undergoing AWR from 2016 to 2021 with BTA versus CST was performed based on BMI, defect width, hernia volume, and CDC wound classification. Demographics, operative characteristics, and outcomes were evaluated. Results 35 BTA vs 105 CST matched patients were analyzed. Hernia defects and volume were large for both the CST and BTA groups (mean size:286.2+179.9cm2vs289.7+162.4cm2;p=0.73) (mean volume:1498.3+2043.4cm3vs2914.7+6539.4cm3;p=0.35). CDC wound classifications were equivalent (CDC3 and 4–39.1%vs40.0%;p=0.97). CST was more frequently performed in European Hernia Society M1 hernias (21% vs 2.9%;p=0.01). The BTA group had fewer surgical site occurrences (SSO) (32.4%vs11.4%;p=0.02) and surgical site infections (SSI) (11.7%vs0%;p=0.04). There was no difference in fascial closure (90.5%vs100%;p=0.11)) or recurrence (12.4%vs2.9%;p=0.10) with similar median follow-up (22.8+29.7vs 9.8+12.7months;p=0.13). In multivariate analysis, BTA was associated with lower rates of SSO (OR=5.3; 95% CI [1.4–34.4]). Conclusion There was no difference in fascial closure rates or in hernia recurrence between the two groups. Pre-operative BTA can thereby achieve similar outcomes as CST while concurrently decreasing the frequency of SSO. This similarity in outcomes is upheld when comparing BTA to both ACST and PCST separately.

P-132 MANAGEMENT OF VENTRAL HERNIA IN OBESITY: OUR ALGORITHM

Abstract Introduction Management of ventral hernia in obese is a complex problem. The methods of weight loss, alternatives if the patient cannot undergo bariatric surgery, timing, and type of hernia surgery lacks clarity and are dependent on resources and expertise. There is a need for algorithms based on local population and expertise. In this paper, we present the outcomes of our institutional algorithm. Methods It was a retrospective analysis of prospectively collected data. Patients with body mass index(BMI) &amp;gt; 30Kg/m2 were included to undergo surgery as per algorithm considering (a) presentation(symptomatic vs asymptomatic), (b) hernia characteristics(defect width, site, reducibility), and (c) obesity characteristics(BMI, subcutaneous fat, android vs gynecoid). Data on age, BMI, comorbidities, tobacco consumption, hernia width, location, contents, previous surgery, intraoperative parameters(the type of surgery, mesh, drain, fixation), and outcomes(seroma, hematoma, infection, recurrence) were collected. Results 50 patients underwent treatment as per the algorithm. Mean BMI was 36.6 ± 7.3 kg/m2. The mean follow-up was 17.6 ± 7.2 months. The mean defect width was 4.8 ± 2.9 cm. There were two (4%) recurrences in patients who underwent an anatomical repair under emergency conditions. None of the patients who underwent an elective repair had a recurrence. Total surgical site occurrence was 12% and surgical site occurrence requiring procedural intervention was 8%. There was one (2%) mortality on postoperative day7 due to myocardial infarction. Conclusion The algorithm has shown encouraging results in the short-to-medium term. Long-term evaluation with a higher number of patients is needed to confirm its usefulness.

P-097 MINIMALLY INVASIVE REPAIR IN SEVERE RECTUS DIASTASIS WITH MIDLINE HERNIA ASSOCIATED IN MALES SHOWS HIGH RECURRENCE IN MID-TERM FOLLOW-UP. CASE-CONTROL STUDY

Abstract Aim Endoscopic plication could develop excessive midline tension that could increase recurrence rate in patients with severe rectus diastasis (SRD). New minimally invasive endoscopic repair (FESSA technique)(FT) was proposed to corrects both pathologies. Aim: assess clinical results, postoperative pain, functional recovery and recurrence of FT compared to endoscopic anterior rectus sheaths plication and mesh (ARSP). Patients and Methods male patients with ventral/incisional hernia and SRD were included. 2017–2019 patient underwent to ARSP. 2019–2020 patients underwent to FT. data: Defect and diastasis width and length. Surgical results: Operation time, Intraoperative complications, Hospital stay,Postoperative complications,Pain on 1th/7th/30th days, Functional recovery, Hernia recurrence. Statistic variables were compared using nonparametric tests. Results 53 patients were included. 28 patients underwent FT and 25 to ARSP. operative time: 70 +/-9 min in FT, 55+/- 7 min in ARSP with significant differences.Hospital stay:1.4+/- 0,5 days for FT and 2,08+/-0,5 for ARSP with significant differences. one postoperative subcutaneous hematoma, requiring surgical removal (2%) in ARSP. Pain at postoperative day 1:21+/2 in FT and 25 +/-2 in ARSP without differences. Pain after 7 and 30 days,significant improvement were shown in favor of FT. functional recovery at 1 month: 17,8 +/-2,4 in FT and 27,8 +/-3,3 in ARSP with significant improvement in FT. recurrence after 24 months: 1 patient in FT (3.6%) and 9 patient in ARSP(36.0%) with significant differences. Conclusions Minimally invasive endoscopic Anterior rectus sheaths plication with mesh in SRD and midline hernias, shows higher recurrence rate, postoperative pain and worse functional recovery due to probably excessive midline tension.

P-073 THE MODIFIED SUBLAY TECHNIQUE FOR THE MANAGEMENT OF MAJOR SUBCOSTAL INCISIONAL HERNIA: LONG-TERM FOLLOW-UP RESULTS OF 41 CONSECUTIVE PATIENTS

Abstract Aim To present the concept of original technique in the management of major incisional subcostal hernias bassed on sublay position of large haevy-weight polypropylene mesh between the two myofascial layers in the anterolateral abdominal wall. Material and methods Between January 2010 and May 2022, 41 consecutive patients underwent the modified sublay technique for major incisional subcostal hernia (minimal defect surface100 cm2 or minimal defect width or height 10 cm). The operative technique is: a) hernia sac dissetion and reposition into the abdominal cavity; b) rectus muscle and rectus muscle stump dissection from posterior rectus sheath, rectus muscle atachement dissection from thoracic wall and external oblique muscle dissection from internal oblique muscle around hernia defect at the side of the hernia defect; c) separate posterior and anterior rectus sheaths reconstruction at the midline; d) reconstruction of the posterior miofascial layer suturing internal oblique/transversal muscle and posterior rectus sheaths; e) large haevy-weight polypropilene mesh placement between posterior and anterior miofascial layer; e) reconstruction of the anterior miofascial layer by suturing external oblique muscle and anterior rectus sheaths. Results A median (range) hernia defect surface was 160 (100–500) cm2. A median operative time was 120 (90–330) minutes. The morbidity rate was 19.5%. A median (range) postoperative hospital stay was 7 (2–24) days. After the median follow-up of 50 (1–124) months, two patients (4,9%) developed recurrent hernia. Conclusions The modified sublay technique using large heavyweight polypropylene mesh provides good results in the management of major subcostal abdominal wall defects.

OC-072 SYSTEMATIC REVIEW AND META-ANALYSIS OF PREOPERATIVE ADMINISTRATION OF BOTULINUM TOXIN AS ADJUNCT TO VENTRAL HERNIA REPAIRS

Abstract Aim Preoperative application of botulinum toxin (BTX), with or without preoperative progressive pneumoperitoneum (PPP), is an adjunct to complex ventral hernia repairs, causing flaccid paralysis. We aim to evaluate the benefit of BTX in the advancement of the lateral musculature and decrease hernia defect width. Material &amp; Methods It was elaborated a systematic review and meta-analysis following PRISMA guidelines and registered at PROSPERO. “Ventral hernia”, “incisional hernia”, “abdominal wall” and “botulinum toxin” were searched. PubMed (Medline), EMBASE (OVID) and LILACS databases research. Results Five studies (235 patients) showed tha BTX significantly increases the lateral abdominal wall muscles length (4,07cm) (95%CI (3.65;4.49), p&amp;lt;0,1 I2=47%). Two studies (113 patients) showes that hernia defect width raised 1.24 cm (95%CI (-3.06;5.53), p&amp;lt;0,05, I2=76%) after BTX with or without PPP. Conclusions Increase in the volume of the abdominal cavity after BTX and PPP by enlargement of abdominal wall muscles may be related to improve outcomes such as decreasing abdominal compartiment syndrome and surgical site occurrences. Despite the Increase in the lateral abdominal wall after BTX, the decrease in hernia defect width was not obseved. Insted, meta-analysis showed a tendency of width increasing, taking into account considerable heterogeneity, witch may be related to PPP association. BTX in complex ventral hernias increases lateral abdominal muscles length and, thus, is suposed to decrease poor surgical outcomes, although the transverse diameter of the defect does not reduced as expected. Futher studies are necessary to evaluate benefits of BTX in complete fascial closure.

Preoperative botulinum toxin A (BTA) injection versus component separation techniques (CST) in complex abdominal wall reconstruction (AWR): A propensity-scored matched study

BackgroundComplete fascial closure significantly reduces recurrence rates and wound complications in abdominal wall reconstruction. While component separation techniques have clear effectiveness in closing large abdominal wall defects, preoperative botulinum toxin A has emerged as an adjunct to aid in fascial closure. Few data exist comparing preoperative botulinum toxin A to component separation techniques, and the aim was to do so in a matched study. MethodsA prospective, single-center, hernia-specific database was queried, and a 3:1 propensity-matched study of patients undergoing open abdominal wall reconstruction from 2016 to 2021 with botulinum toxin A versus component separation techniques was performed based on body mass index, defect width, hernia volume, and Centers for Disease Control and Prevention wound classification. Demographics, operative characteristics, and outcomes were evaluated. ResultsMatched patients included 105 component separation techniques and 35 botulinum toxin A. There was no difference in tobacco use, diabetes, or body mass index (all P > .5). Hernia defects and volume were large for both the component separation techniques and botulinum toxin A groups (mean size: component separation techniques 286.2 ± 179.9 cm2 vs botulinum toxin A 289.7 ± 162.4 cm2; P = .73) (mean volume: 1,498.3 + 2,043.4 cm3 vs 2,914.7 + 6,539.4 cm3; P = .35). Centers for Disease Control and Prevention wound classifications were equivalent (CDC3 and 4%–39.1% vs 40.0%; P = .97). Component separation techniques were more frequently performed in European Hernia Society M1 hernias (21% vs 2.9%; P = .01). The botulinum toxin A group had fewer surgical site occurrences (32.4% vs 11.4%; P = .02) and surgical site infections (11.7% vs 0%; P = .04). In multivariate analysis, botulinum toxin A was associated with lower rates of surgical site occurrences (odds ratio = 5.3; 95% confidence interval [1.4–34.4]). There was no difference in fascial closure (90.5% vs 100%; P = .11) or recurrence (12.4% vs 2.9%; P = .10) with follow-up (22.8 + 29.7 vs 9.8 + 12.7 months; P = .13). ConclusionIn a matched study comparing patients with botulinum toxin A versus component separation techniques, there was no difference in fascial closure rates or in hernia recurrence between the 2 groups. Preoperative botulinum toxin A can achieve similar outcomes as component separation techniques, while decreasing the frequency of surgical site occurrences.

Laser ultrasonics and machine learning for automatic defect detection in metallic components

This paper develops an automatic and reliable nondestructive evaluation (NDE) technique that enables quantification of the width and depth of subsurface defects of metallic components simultaneously by using non-contact laser ultrasonic technique and identified machine learning (ML) algorithm. Twenty-two specimens with various subsurface defect dimensions are designed and fabricated for laser ultrasonic experiments, and a total of 220 labeled laser ultrasonic signals are obtained for training and verifying ML models. Twelve features, including four time-domain features (maximum, minimum, peak-to-peak, and |Neg|/Pos value of the laser generated Rayleigh ultrasonic waves) and eight wavelet energy features, are identified and extracted as sensitive feature vectors for establishing the dataset. The principal component analysis (PCA) is implemented as dimensionality reduction method of feature vectors to optimize the recognition algorithm and improve the detection accuracy. Three widely used ML models in NDE, adaptive boosting (Adaboost), extreme gradient boosting (XGBboost), and support vector machine (SVM), combined with the PCA are proposed and compared for detecting both the width and depth of subsurface defects. The PCA-XGBoost achieves the highest recognition rate of 98.48%, and is therefore identified as the most effective approach for analyzing laser-ultrasonic signals. Unlike published reports, the proposed model is trained and evaluated with experimental data covered various classification labels, which is more adaptive and reliable in practical application than the models established using simulated data or limited experimental data. In other applications, as long as sufficient laser ultrasonic data with regards to various defect properties (dimensions, orientations, locations, shapes, etc.) can be acquired, the developed approach can realize accurate detection of corresponding defects.

Logistic regression analysis of risk factors for intra-abdominal hypertension after giant ventral hernia repair: a retrospective cohort study.

Intra-abdominal hypertension (IAH) is a classical complication after giant ventral hernia surgery and may lead to abdominal compartment syndrome (ACS). Assessment of risk factors and prevention of IAH/ACS are essential for hernia surgeons. We performed a retrospective study including 58 giant ventral hernia patients in our center between Jan 1, 2017, and Mar 1, 2022, we recorded age, gender, chronic obstructive pulmonary disease (COPD), coronary heart disease (CHD), hypertension, type 2 diabetes mellitus (T2DM), hypoproteinemia, body mass index (BMI), the ratio of hernia sac volume to abdominal cavity volume (HSV/ACV), defect width, tension reduction procedure (TRP), positive fluid balance (PFB) and IAH of these patients and analyzed the data using univariate and multivariate logistic regression to screen the risk factors for IAH after surgery. The multivariate analysis showed that HSV/ACV ≥ 25%, hypoproteinemia, and PFB were independent risk factors for the occurrence of IAH after giant ventral hernia repair (P = 0.025, 0.016, 0.017, respectively). We did not find any correlation between postoperative IAH and the patient's age, gender, COPD, CHD, hypertension, T2DM, BMI, defect width, TRP, and PFB. Identifying risk factors is of great significance for the early identification and prevention of IAH/ACS. We found that HSV/ACV ≥ 25%, hypoproteinemia, and PFB were independent risk factors for IAH after giant ventral hernia repair.

Rail head surface defect magnetic flux leakage signal filtering based on the relativity among the adjacent sensors

Rail is the infrastructure of railway traffic and magnetic flux leakage (MFL) is commonly used to detect the surface defects of ferromagnetic materials such as rail. A correlation-based filtering method is proposed to inhibit the lift-off jamming in MFL detection for the defects in the rail head surface. The detection data is segmented and the two sensors with the minimum correlation coefficient of their outputs in the × direction are found. The possible defect width and depth according to the maximum of each output is estimated and the leakage magnetic field (LMF) of it is calculated. The output of the sensor with smaller correlation coefficient between the calculation LMF and the sensor output is chosen as the reference signal to filter. An experimental system was constructed to detect the artificial defects in the rail head surface, and the experimental results shown that the method reduces the lift-off jamming.

S041-Trends and short-term outcomes of three approaches to minimally invasive repair of small ventral hernias. An ACHQC analysis.

Different approaches and mesh positions are used for minimally invasive ventral hernia repair (MIS-VHR).Our aim was to evaluate the trends and short-term outcomes of intraperitoneal onlay mesh (IPOM), preperitoneal, and retromuscular repairs for small ventral hernias. We conducted a retrospective cohort study using the Abdominal Core Health Quality Collaborative (ACHQC). We included elective MIS-VHR in adults with hernia defect width < = 6cm from 2012 to 2021. We compared patient/hernia characteristics, trends, and short-term outcomes between IPOM, preperitoneal, and retromuscular repairs. Inverse probability of treatment weighting (IPTW) was used to balance baseline characteristics. A total of 7261 patients were included (IPOM = 4484, preperitoneal = 1829, retromuscular = 948). Preperitoneal repair was associated with lower rates of incisional (preperitoneal = 37%, IPOM = 63%, retromuscular = 73%) and recurrent hernias (preperitoneal = 11%, IPOM = 21%, retromuscular = 22%) compared to IPOM and retromuscular. Median defect width was 3.0, 2.0, and 4.0cm for IPOM, preperitoneal, and retromuscular, respectively. There has been a progressive increase in the proportion of preperitoneal and retromuscular repairs over time (10% in 2013-53% in 2021 of all MIS-VHR). Robotic approach was more frequently utilized in preperitoneal and retromuscular (both > 85%) compared to IPOM (47%). Transversus abdominis release was performed in 14% of retromuscular repairs. After IPTW, no clinically significant differences were noted in the short-term outcomes between IPOM versus preperitoneal. Retromuscular repairs were associated with higher risk of 30-day reoperation (OR = 3.54, 95%CI [1.67, 7.5] and OR = 5.29, 95%CI [1.23, 22.74]) compared to IPOM and preperitoneal repairs, respectively, and higher risk of 30-day readmission compared to preperitoneal repairs (OR = 2.6, 95%CI [2.6, 6.4]). Based on ACHQC data, preperitoneal and retromuscular approaches for MIS-VHR of small hernias have increased over time and are primarily performed robotically. Transversus abdominis release was performed in 14% of retromuscular repairs of these small hernias. Retromuscular repairs were associated with higher 30-day readmission and reoperation rates compared to the other approaches.