Anatomical Mesh Research Articles

WP1.11 - Total Extra Peritoneal (TEP) Inguinal hernia repair is safe and feasible for recurrent inguinal hernia post Total Extra Peritoneal repair "TEP on TEP is possible”

Abstract This abstract share our experience in surgical management of recurrent inguinal hernia post total extra peritoneal (TEP) repair by utilizing the same approach TEP. Methods Two patients with recurrent inguinal hernia post TEP were consulted for laparoscopic VS open approach, and both opted for the laparoscopic approach, understanding the higher risk of conversion. Result The first case of 62y male with recurrent left inguinal hernia after bilateral TEP. The second case of 69y male with recurrent left inguinal hernia post lap TEP repair. Standard three lower midline ports technique, no balloon spacer was used. The first and most important step was developing the plane above the previous mesh. 20 ml of 1 % xylocaine and 1/200000 was instilled in the extra peritoneal space to minimize oozing. Separating the previous mesh from the inferior epigastric artery and posterior wall of rectus muscle, down into bony lard marks and cord structures was performed using suction and sharp dissection with minimal diathermy. All landmarks were exposed in the three zones, before utilizing anatomical mesh. Both patients stayed overnight and operation time was 84 and 90 minute respectively. Three months follow up showed no recurrence or significant pain. Conclusion To our knowledge, this is first study describe the use of TEP on TEP. It suggests that TEP should not be excluded in patients with previous posterior mesh repair, emphasizing the importance of proper consultation. The abstract calls for further cases and studies to assess the efficacy and safety of this approach.

Criteria for choosing a mesh implant in laparoscopic Transabdominal Preperitoneal Patch hernioplasty

Laparoscopic Transabdominal Preperitoneal Patch hernioplasty is an important method of treating inguinal hernias, but the lack of data on the comparative effectiveness of anatomical 3D mesh and traditional flat mesh makes it difficult to choose the optimal implant to reduce the risk of recurrence and complications. The aim of the study was to compare the effectiveness of anatomical 3D mesh and traditional flat mesh in laparoscopic hernioplasty with Transabdominal Preperitoneal Patch, as well as to determine the key criteria for implant selection. The objectives of the study were to analyse the recurrence rate, duration of surgery, postoperative pain, complication rate and patient satisfaction in the two groups. The study included 187 patients who were divided into two groups: 92 patients received traditional flat meshes and 95 patients received 3D anatomical meshes. Data were collected over 18 months and analysed using statistical methods. The use of anatomical 3D meshes reduced the time of surgery. The average level of postoperative pain according to the Visual Analogue Scale in the group with anatomical meshes was 30% lower. The complication rate in the anatomical mesh group was 5%, while in the flat mesh group it was 12%. Patient satisfaction in the group with anatomical 3D meshes was significantly higher. The results of the study confirm the advantage of anatomical 3D mesh in laparoscopic hernioplasty with Transabdominal Preperitoneal Patch, which reduces the time of surgery, reduces the incidence of recurrence, postoperative pain and complications, and increases patient satisfaction

A Semi-automatic Pipeline for Generation of Large Cohorts of Four-Chamber Heart Meshes.

Computational models for cardiac electro-mechanics have been increasingly used to further understand heart function. Small cohort and single patient computational studies provide useful insight into cardiac pathophysiology and response to therapy. However, these smaller studies have limited capability to capture the high level of anatomical variability seen in cardiology patients. Larger cohort studies are, on the other hand, more representative of the study population, but building several patient-specific anatomical meshes can be time-consuming and requires access to larger datasets of imaging data, image processing software to label anatomical structures and tools to create high fidelity anatomical meshes. Limited access to these tools and data might limit advances in this area of research. In this chapter, we present our semi-automatic pipeline to build patient-specific four-chamber heart meshes from CT imaging datasets, including ventricular myofibers and a set of universal ventricular and atrial coordinates. This pipeline was applied to CT images from both heart failure patients and healthy controls to generate cohorts of tetrahedral meshes suitable for electro-mechanics simulations. Both cohorts were made publicly available in order to promote computational studies employing large virtual cohorts.

Advancing clinical translation of cardiac biomechanics models: a comprehensive review, applications and future pathways.

Cardiac mechanics models are developed to represent a high level of detail, including refined anatomies, accurate cell mechanics models, and platforms to link microscale physiology to whole-organ function. However, cardiac biomechanics models still have limited clinical translation. In this review, we provide a picture of cardiac mechanics models, focusing on their clinical translation. We review the main experimental and clinical data used in cardiac models, as well as the steps followed in the literature to generate anatomical meshes ready for simulations. We describe the main models in active and passive mechanics and the different lumped parameter models to represent the circulatory system. Lastly, we provide a summary of the state-of-the-art in terms of ventricular, atrial, and four-chamber cardiac biomechanics models. We discuss the steps that may facilitate clinical translation of the biomechanics models we describe. A well-established software to simulate cardiac biomechanics is lacking, with all available platforms involving different levels of documentation, learning curves, accessibility, and cost. Furthermore, there is no regulatory framework that clearly outlines the verification and validation requirements a model has to satisfy in order to be reliably used in applications. Finally, better integration with increasingly rich clinical and/or experimental datasets as well as machine learning techniques to reduce computational costs might increase model reliability at feasible resources. Cardiac biomechanics models provide excellent opportunities to be integrated into clinical workflows, but more refinement and careful validation against clinical data are needed to improve their credibility. In addition, in each context of use, model complexity must be balanced with the associated high computational cost of running these models.

Development and Implantation of 3D Anatomically Tailored Polypropylene Mesh for Laparoscopic Inguinal Hernia Repair Designed on the Basis of CT Images (the ILAM Study).

The aim of the ILAM (Individualized Laparoscopic Anatomical Mesh) study was to create and implant a fully individualized mesh based on CT scans, taking into account the published body of knowledge about the material and mechanical behavior of the implant for laparoscopic inguinal hernia repair. The team creating and conducting this study consisted of surgeons and engineers. A specific project was made and divided into 4 phases. The process of development and implantation was divided into 4 milestones: CT scans and modeling based on predefined subgroups, mesh manufacture, certification and clinical evaluation. The result of the study was the first individually designed hernia mesh to have been implanted in a human subject. After 12months of follow-up, no recurrences or other complications were reported. The new mesh provides a better anatomic fit to the patients' inguinal region geometry. Mechanical stability is ensured by the multiple contact points between the implant and the tissues, which generate friction forces. Together with the possibility of shape design (proper overlap), the authors believe that there is no need for mesh fixation. If so, the use of such design meshes can change the guidelines in laparoendoscopic hernia repair in the future.

Does the Weight Matter? Short-Term Outcomes of Lightweight Versus Heavyweight Three-Dimensional Anatomical Mesh in Minimally Invasive Inguinal Hernia Repair.

Background: The type of mesh used in inguinal hernia repairs remains controversial. There are limited data looking at specific mesh-related complications. The objective of this study is to assess postoperative 90-day outcomes in lightweight (LW) and heavyweight (HW) anatomical mesh in minimally invasive inguinal hernia repairs. Methods: A retrospective single-center database was queried for all adult minimally invasive inguinal hernia repairs with anatomical mesh from July 2016 to March 2021. Demographics and surgical outcomes were analyzed. Univariate analysis and multivariate logistic regression were performed. Results: Six hundred forty-seven minimally invasive inguinal hernia repairs were performed with 423 (65.3%) using HW and 224 (24.7%) using LW mesh. There was no difference in mean body mass index between the groups (26.9 ± 4.2 kg/m2 in the LW group and 27.1 ± 4.2 kg/m2 in the HW group; P = .69). There was no difference in type of mesh fixation used in either group, with tacker being the most common. There was no difference in postoperative emergency department (ED) visit (P = .625), readmission rates (P = .562), or postoperative complications between the two groups. Fifty patients presented with seroma within 90 days. There were five recurrences in each group and only one surgical site infection in the LW within 90 days. Multivariate logistic regression was performed, and predictors of seroma formation included age (odds ratio [OR] 1.02; confidence interval [CI] 1-1.04; P = .02) and hypertension (HTN) (OR 1.8; CI 1.03-3.4; P = .039). HW mesh was not associated with seroma formation (OR 1.04; CI 0.5-1.9; P = .895). Similarly, HW mesh was not associated with surgical site occurrences (SSO) (OR 1.04; CI 0.5-1.8; P = .872). HTN was associated with SSO (OR 1.74; CI 1-3.05; P = .048). Conclusion: Our study did not favor the use of LW or HW mesh when comparing postoperative complications or clinical outcomes. HW mesh was not associated with either seroma formation or SSO.

The first experience with the Dextile anatomical mesh in laparoscopic inguinal hernia repair.

The Dextile Anatomical mesh (Medtronic) is a polypropylene heavyweight mesh and has a 3D patented anatomical shape which adapts to the contours of the extra-peritoneal inguinal region without the need for fixation, potentially reducing the risk of hernia recurrence and chronic post-operative pain. This retrospective study will be the first study to assess the outcomes of the Dextile Anatomical mesh compared to another three-dimensional mesh, the 3DMax mesh (Bard). Between 2019 and 2022, all patients who underwent an elective unilateral inguinal hernia repair were assessed. 416 patients in the Dextile Anatomical mesh group and 540 patients in the 3DMax mesh group were included. Outcomes were intra- and post-operative complications, inguinal hernia recurrence and chronic post-operative inguinal pain. No significant differences were found between the two groups regarding intra- and post-operative complications including wound infection, antibiotic use, hematoma, seroma, urinary retention and delayed wound healing. 1-year recurrence rate was comparable for the Dextile Anatomical mesh group and the 3DMax mesh group, respectively, 3.8% and 3.0%, P = 0.45. Chronic post-operative inguinal pain was similar for the Dextile Anatomical mesh (3.4%) and the 3DMax mesh (3.0%), P = 0.72. This retrospective study comparing the relatively new Dextile Anatomical mesh (Medtronic) with the 3D Max mesh (Bard) in unilateral inguinal hernia repair showed that both meshes are safe and effective to use. There were no significant differences in intra-operative outcomes, recurrence rates and chronic post-operative inguinal pain.

BJS-03 DEVELOPMENT AND IMPLANTATION OF 3D ANATOMICALLY TAILORED POLYPROPYLENE MESH FOR LAPAROSCOPIC INGUINAL HERNIA REPAIR DESIGNED ON THE BASIS OF CT IMAGES (THE ILAM STUDY)

Abstract Aim The aim of the ILAM (Individualized Laparoscopic Anatomical Mesh) study was to create and implant a fully individualized mesh based on CT scans, taking into account the published body of knowledge about the material and mechanical behavior of the implant for laparoscopic inguinal hernia repair. Material and Methods The team creating and conducting this study consisted of surgeons and engineers. A specific project was made and divided into four phases. The process of development and implantation was divided into four milestones: CT scans and modeling based on predefined subgroups, mesh manufacture, certification and clinical evaluation. Results The result of study was first individually designed hernia mesh to have been implanted in a human subject. After 12-months of follow-up no recurrences or other complications were reported. Conclusions New mesh that provides a better anatomic fit to the patients’ inguinal region geometry. Mechanical stability is ensured by the multiple contact points between the implant and the tissues, which generate friction forces. Together with possibility of shape design (proper overlap) the authors believe that there is no need of mesh fixation. If so, the use of such design meshes can change the guidelines in laparo/endoscopic hernia repair in the future.

Early Results of Comparison of Hydrophilic Anatomical Mesh and Polypropylene Mesh for Laparoscopic Total Extraperitoneal (TEP) Inguinal Hernia Repair.

To compare the results, feasibility, and effectiveness of laparoscopic total extraperitoneal (TEP) hernia repair made using anatomical hydrophilic mesh and polypropylene mesh. Descriptive study. Department of General Surgery, Recepc Tayyip Erdoğan University Training and Research Hospital, Rize, Turkey and Department of General Surgery, Ondokuz Mayıs University Medical Faculty, Samsun, Turkey from January 2017 to October 2020. Comparative analysis on patient who had TEP for inguinal hernia. Group 1 included repairs using hydrophilic anatomical mesh, Group 2 included repairs using polypropylene mesh. Both were compared for operation times, complications, and return to work. There were 34 patients in Group 1 and 31 patients in Group 2. The average operation time was shorter in Group 1 (p = 0.001). Postoperative complications, were significantly less common in Group 1 (p = 0.045). Patients were able to return to their work-life earlier in Group 1 after surgery (p = 0.001). Both anatomic mesh and polypropylene mesh can be used in TEP hernia repair. These two materials stand out with their different properties. Whereas anatomical mesh shortens the operation time, decreases the rate of postoperative complications, and enables the early return to work, polypropylene mesh is cost-effective and easily accessible. Inguinal hernia, Postoperative complication, Laparoscopic total extraperitoneal (TEP).

Anatomical Repair Versus Intra Peritoneal Mesh Repair of Umbilical and Paraumbilical Hernia in Ascitic Patients: Randomized Controlled Study

Anatomical Repair Versus Intra Peritoneal Mesh Repair of Umbilical and Paraumbilical Hernia in Ascitic Patients: Randomized Controlled Study

PO-691-01 PHYSIOLOGIC, REALISTIC, COMPUTER MODELING OF ATRIAL FIBRILLATION TO FACILITATE THE DEVELOPMENT AND TESTING OF TREATMENT STRATEGIES

An interactive, physiologically realistic (PR), and accurate computer simulation allows multiple scenarios to be tested in a “live” environment and has become a key step in the rapid development and testing of treatment strategies for atrial fibrillation (AF). Develop an accurate model of AF that allows the user to define the regions and zones of anisotropic conduction to test the effectiveness of a variety of AF treatment strategies. A model was developed using standard electrophysiologic (EP) parameters established in the literature. An advanced implementation of the Fitzhugh-Nagumo model reproduces the action potential morphology of the human atrium enabling live simulation. To reproduce the complex conduction patterns (CCPs) of AF identified in the EP lab, a bi-layer model was implemented to represent epi- and endocardial dissociation. The model allows a user to define regions of fibrosis, zones of slow conduction, and action potential duration (APD). The user graphically draws these regions and zones with gradients that span entered max and min values of conduction velocity (CV) and APD. The EP lab experience and workflow is reproduced, with CCPs visualized on a 3D anatomy and calculated potentials displayed as 2D traces. To test the CCPs and performance of the model, isolated zones of conduction were delineated on a 3D LA model, with assigned sites of pacing and recording. Model produces accurate atrial CCPs for anatomical meshes > 20k triangles, with expected source-sink block-velocity < 5 cm/s (Figure 1). Regions of anisotropic conduction were applied to match a human AF substrate mapped by Acutus AcQMap, with PVI-block plus 2 anterior, 1 posterior, 1 roof, 1 mitral-isthmus slow conduction zones (0.1 - 50 cm/s); 1 anterior APD zone (65 - 110 ms); and anterior and posterior regions of endo-epi fibrosis (density = 25%, CV = 8 - 25 cm/s). Model produced similar CCPs to human with rotational and pivoting reentry at the same locations (Figure 2). A PR model of AF was developed that allows a user to define regions of fibrosis and zones of conduction abnormalities prominent in AF. The model can be used for developing and testing advanced treatment strategies. Clinical application is feasible, including input of procedural data to achieve optimal treatment strategies.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Quantification of Tumor Location and Growth for Orthotopic Pancreatic Cancer Model Using Bioluminescence Tomography-Guided System

<h3>Purpose/Objective(s)</h3> The developing radio-immunotherapy has cast the use of radiation therapy (RT) into a pivotal role in the management of pancreatic cancer. There is a need to study pancreatic cancer in pre-clinical setting to advance our understanding of the role of RT. The challenge to study abdominal malignancy in vivo is lack of proper imaging guidance. Bioluminescence with its strong imaging contrast has been widely used to monitor tumor growth. We innovated 3D bioluminescence tomography (BLT) to guide irradiation for an orthotopic pancreatic ductal adenocarcinoma (PDAC), and monitor its growth and treatment response. <h3>Materials/Methods</h3> To establish the orthotopic PDAC model, we implanted a fraction of BxPc3-Red-FLuc tumor into the pancreas of a nude mouse. For BLT, mice were subject to multi-spectral and multi-projection bioluminescence imaging (BLI), followed by small animal radiation research platform (SARRP) CBCT imaging. CBCT image was acquired to generate anatomical mesh for BLT reconstruction. We inserted a titanium wire to the center of tumor as the marker to validate the BLT localization accuracy. We will also quantify the accuracy of BLT reconstructed volume with MRI and ex vivo method. Volume-averaged bioluminescent power (BP), related to tumor viability, will also be assessed in comparing with surface BLI and ex vivo method, to determine if it is a proper metric for tumor monitoring and assessment. We will further irradiate the in vivo PDAC volume guided by BLT and demonstrate the application of BLT to longitudinally assess the change of PDAC volume/power in response to treatment. <h3>Results</h3> Our initial result shows 3D BLT can retrieve the orthotopic PDAC location within 1.5 mm accuracy at depth from 3-5 mm, common depth observed in pancreatic study. The BP is observed linearly by 12-fold along the tumor growth 4 weeks after tumor implantation. With BLT, we are able to reconstruct the 3D bioluminescent tumor volume using multiple-projection imaging. <h3>Conclusion</h3> The quantitative BLT system offers unique opportunities for researchers to study important pancreatic tumor in orthotopic setting to quantify its location, growth and response to therapeutic intervention.

Robotic Inguinal Hernia Repair After Prostatectomy: How to Navigate Safely.

In recent decades, minimally invasive approaches have found their place in treating a specific subset of patients with inguinal hernias, predominantly those with recurrent or bilateral disease. Classically, prior history of urologic pelvic operations, such as prostatectomy, has been listed as relative contraindication for minimally invasive inguinal hernia repair. As the adoption of the robotics platform continues to grow, we aim to outline a feasible robotic-assisted inguinal hernia repair technique in patients with previous prostatectomies. We report the outcomes of 15 patients who underwent repair at 2 institutions. This is a retrospective case series of 15 patients who underwent robotic transabdominal preperitoneal approach repair of their inguinal hernias after prostatectomy. Demographics, intraoperative variables, and outcomes of our cases are described. Fifteen patients were included in our cohort. All patients had a history of prostatectomy (7 open, 2 laparoscopic, and 6 robotic) due to prostate cancer. Median age was 70 years old (range: 60 to 89 y), with a median body mass index of 26.3 kg/m2 (range: 20.5 to 37.4 kg/m2). Hernia defects were bilateral in 6 patients and unilateral in the remaining 9 (right; 6, left; 3). The shortest interval between prostatectomy and subsequent hernia repair was 4 months (range: 4 to 216 mo). The median operative time was 139 min (range: 91 to 281 min). All defects were repaired using a polypropylene mesh except in 1 case, where a coated monofilament polyester mesh was used after having a large peritoneal defect to close, preventing future adhesions to the bowel. Mesh sizes used were large (16×11 cm), extra-large (17×12 cm) for anatomic mesh, and 20×15 cm for the monofilament polyester mesh. The mesh was fixed in 14 of 15 cases. Fixation was accomplished with absorbable suture (n=13), barbed suture (n=1), and fibrin sealant (n=1). Peritoneal closure was always performed using a continuous running v-loc suture. There were no documented major intraoperative complications, no 30-day readmission, or recurrences recorded within the follow-up period. Postoperatively, only 2 seromas and 1 hematoma were documented during the follow-up period. Robotic inguinal hernia repairs in patients with previous prostatectomy is safe and feasible in most patients. Larger patient series are needed to confirm these findings.

A novel anatomic titanium mesh cage for reducing the subsidence rate after anterior cervical corpectomy: a finite element study

Fusion with a titanium mesh cage (TMC) has become popular as a conventional method after cervical anterior corpectomy, but postoperative TMC subsidence has often been reported in the literature. We designed a novel anatomic cervical TMC to reduce the postoperative subsidence rate. According to the test process specified in the American Society of Testing Materials (ASTM) F2267 standard, three-dimensional finite element analysis was used to compare the anti-subsidence characteristics of a traditional TMC (TTMC) and novel TMC (NTMC). Through analysis, the relative propensity values of a device to subside (Kp) of the TTMC and NTMC were 665.5 N/mm and 1007.2 N/mm, respectively. A higher Kp measurement is generally expected to indicate that the device is more resistant to subsidence into a vertebral body. The results showed that the novel anatomic titanium mesh cage (NTMC) significantly improved the anti-subsidence performance after anterior cervical corpectomy and fusion (ACCF), which was approximately 51.3% higher than that of the traditional titanium mesh cage.

Regional Differences in Height, Weight, and Body Composition may Result from Photoperiodic Responses: An Ecological Analysis of Japanese Children and Adolescents.

This ecological study examined whether geographical differences in the physique of Japanese children and adolescents can be explained from the perspective of photoperiodicity induced by effective day length (light duration exceeding a certain threshold of illuminance) using prefecture-level anatomical data and Mesh Climatic Data. Multiple regression analysis for height prediction demonstrated that when controlled by weight, effective day lengths of the longest and shortest months were inversely correlated with height distribution. Conversely, for weight prediction, when controlled by height, the effective day lengths of the longest and shortest months were positively correlated with weight distribution. The regression coefficients were greater for the effective day length of the shortest month in both height and weight prediction. This phenomenon where the same two explanatory variables are negatively correlated with height and positively correlated with weight in a significant manner is rare, and there may be no physiological interpretation of this phenomenon other than one based on changes in thyroid hormone signaling. These distribution characteristics are common to the photoperiodicity by which seasonal breeding vertebrates reciprocally switch thyroid hormone signaling according to prior photoperiodic history through epigenetic functions. From these perspectives, thyroid hormone signaling in a certain region was assumed to be activated in summer according to the prior shorter winter day length and inactivated in winter according to the prior longer summer day length. Regarding the prevalence of obesity, the coexistence of longer summer and winter day lengths was thought to set body composition to be short and fat in early adolescence.

Abstract 17254: Right Ventricular Myoarchitecture is Associated With RV Function in Pulmonary Arterial Hypertension

Introduction: Right Ventricular (RV) dysfunction in pulmonary arterial hypertension (PAH) is the major cause of mortality. Myocardial architecture determines the basis of heart function and can be assessed by generalized Q-space imaging by MRI (GQI), yet remains understudied in the RV. Therefore, we assessed myocardial fiber architecture patterns and correlated them with disease severity in two models of PAH. Methods: PAH was induced in Sprague-Dawley (SD) and Fischer (CDF) male rats by SU5416 (20 mg/kg; s.c.) followed by 3 wks of hypoxia (10% FiO2). Controls received vehicle and were kept at normoxia. After 4 wks, echocardiography and hemodynamics were performed. Whole hearts were resected in some animals (SD n=9, CDF n=8) and imaged via high-angular resolution GQI using a 7T magnet (512 directions, b=750 s/mm2). Patterns of inter-voxel coherence (tractography) were reconstructed, and transmural helix angle distribution (HAD) were assessed at 3 points across the LV and RV (Panel A) and normalized to a common vector. Finite-element models were developed via registering myofiber direction to anatomical mesh. Results: Both animal strains developed PAH, however CDF rats had lower pulmonary artery acceleration time (14±0.6 vs. 19±1.3 ms, p&lt;0.05) and TAPSE (1.5±0.06 vs. 1.9±0.09 mm, p&lt;0.05) and higher RV afterload (1023±167 vs. 285±17, mmHg/mL p&lt;0.05) compared to SD. PAH was associated with steeper slope of the RV transmural HAD in both SD and CDF vs. controls and slightly higher in CDF-PAH compared to SD-PAH (Panel B). No significant changes were noted in the LV (Panel C). Moreover, the RV HAD slope significantly correlated to RV functional parameters (TAPSE r= 0.58, RV global longitudinal strain r= -0.49) and RA area (r= -0.58). Transmural and regional variation in fiber direction was also observed (Panel D). Conclusion: Myoarchitectural analysis of the RV in the setting of PAH reveals that myocardial HAD relates to functional parameters and may be a marker of maladaptation.

Fast Track Surgery in laparoscopic treatment of inguinal hernias

Background. Minimally invasive surgical techniques for inguinal hernia repair reduce the body’s overall stress response to surgical tissue damage, the risk of complications, the percentage of postoperative acute and chronic pain, recovery time.&#x0D; Objective. To improve short-term (acute inguinal pain in the early postoperative period) and long-term (chronic inguinal pain in the long-term follow-up) results of surgical treatment of patients with acquired inguinal hernia by using the modified (sutureless, without mesh fixation) laparoscopic technique of transabdominal preperitoneal hernioplasty (TAPP) with application of Fast Track Surgery guidelines.&#x0D; Materials and methods. The retrospective clinical study included 124 patients aged 18 to 88 years (mean age – 46±2.1) with primary unilateral inguinal hernias who were operated on the clinical bases of the Department of Surgery and Vascular Surgery of Shupyk National Medical Academy of Postgraduate Education. The observation period was 3 years. Modified TAPP was performed in 78 patients (spinal anesthesia, local anesthesia of trocar wounds, terminal peritoneal anesthesia, preperitoneal infiltration of affected inguinal region dissection by local anesthetics, using of anatomical 3D mesh, sutureless restoration of peritoneal defect by electric welding method) and Lichtenstein technique was performed in 46 patients. The peritoneal defect in the main group after implant placement was restored by spot welding.&#x0D; There was experimental study before proceeding the clinical study. The experimental section of the work included 12 rabbits weighing 1.95-3.75 kg (average weight – 2.30±0.52). Each animal was cut peritoneum in three places on both sides of laparotomy with next reconstruction of the defect on one side by welding, and on the other – by suturing with synthetic suture material.&#x0D; Results and discussion. In biological samples from experimental animals, there was decreasing of number of live mesotheliocytes which did not increase the severity of the inflammatory reaction (p˂0.001). A statistically significant difference was observed in the welded scars with higher intensity of collagen formation than in the ligature scars, which provided greater strength of the tissue connection.&#x0D; There was a reduction in the patient’s length of stay in the hospital in 4.2 times in the group of modified technique. There was a reduction in the period before the ability to perform professional duties in 3.4 times in the group of new surgical method. There was no significant difference in the levels of postoperative complications (p=0.036) and re-operations due to complications (p=0.023). In the group of modified surgical treatment there were significant lower rates in the indicators of pain at rest (p&lt;0.001), pain during exercise (p&lt;0.001), recurrence rates (p&lt;0.001). There was a decrease in the need for analgetics in the main group in the early postoperative period (p˂0.001) and a reduction in the risk of prolonged inguinodynia (p˂0.001).&#x0D; Conclusions. The obtained results demonstrate the effectiveness of the use of modified laparoscopic transabdominal preperitoneal hernia mesh repair for primary unilateral inguinal hernias with using Fast Track Surgery protocols with regard improving quality of life of patients in the early and long postoperative period and reduction of the risk of recurrence.

In Vivo Bioluminescence Tomography Center of Mass-Guided Conformal Irradiation

The cone-beam computed tomography (CBCT)-guided small animal radiation research platform (SARRP) has provided unique opportunities to test radiobiologic hypotheses. However, CBCT is less adept to localize soft tissue targets growing in a low imaging contrast environment. Three-dimensional bioluminescence tomography (BLT) provides strong image contrast and thus offers an attractive solution. We introduced a novel and efficient BLT-guided conformal radiation therapy and demonstrated it in an orthotopic glioblastoma (GBM) model. A multispectral BLT system was integrated with SARRP for radiation therapy (RT) guidance. GBM growth curve was first established by contrast CBCT/magnetic resonance imaging (MRI) to derive equivalent sphere as approximated gross target volume (aGTV). For BLT, mice were subject to multispectral bioluminescence imaging, followed by SARRP CBCT imaging and optical reconstruction. The CBCT image was acquired to generate anatomic mesh for the reconstruction and RT planning. To ensure high accuracy of the BLT-reconstructed center of mass (CoM) for target localization, we optimized the optical absorption coefficients μa by minimizing the distance between the CoMs of BLT reconstruction and contrast CBCT/MRI-delineated GBM volume. The aGTV combined with the uncertainties of BLT CoM localization and target volume determination was used to generate estimated target volume (ETV). For conformal irradiation procedure, the GBM was first localized by the predetermined ETV centered at BLT-reconstructed CoM, followed by SARRP radiation. The irradiation accuracy was qualitatively confirmed by pathologic staining. Deviation between CoMs of BLT reconstruction and contrast CBCT/MRI-imaged GBM is approximately 1 mm. Our derived ETV centered at BLT-reconstructed CoM covers >95% of the tumor volume. Using the second-week GBM as an example, the ETV-based BLT-guided irradiation can cover 95.4% ± 4.7% tumor volume at prescribed dose. The pathologic staining demonstrated the BLT-guided irradiated area overlapped well with the GBM location. The BLT-guided RT enables 3-dimensional conformal radiation for important orthotopic tumor models, which provides investigators a new preclinical research capability.

Probabilistic Interpolation of Uncertain Local Activation Times on Human Atrial Manifolds.

Local activation time (LAT) mapping of the atria is important for targeted treatment of atrial arrhythmias, but current methods do not interpolate on the atrial manifold and neglect uncertainties associated with LAT observations. In this paper, we describe novel methods to, first, quantify uncertainties in LAT arising from bipolar electrogram analysis and assignment of electrode recordings to the anatomical mesh, second, interpolate uncertain LAT measurements directly on left atrial manifolds to obtain complete probabilistic activation maps, and finally, interpolate LAT jointly across both the manifold and different S1-S2 pacing protocols. A modified center of mass approach was used to process bipolar electrograms, yielding a LAT estimate and error distribution from the electrogram morphology. An error distribution for assigning measurements to the anatomical mesh was estimated. Probabilistic LAT maps were produced by interpolating on a left atrial manifold using Gaussian Markov random fields, taking into account observation errors and characterizing LAT predictions by their mean and standard deviation. This approach was extended to interpolate across S1-S2 pacing protocols. We evaluated our approach using recordings from three patients undergoing atrial ablation. Cross-validation showed consistent and accurate prediction of LAT observations both at different locations on the left atrium and for different S1-S2 intervals. Interpolation of scalar and vector fields across anatomical structures from point measurements is a challenging problem in biomedical engineering, compounded by uncertainties in measurements and meshes. New methods and approaches are required, and in this paper, we have demonstrated an effective method for probabilistic interpolation of uncertain LAT.

BIOMECHANICAL ANALYSIS TO VERIFY THE BUTTRESS THEORY WHEN USING THE ANATOMICAL THIN TITANIUM MESH PLATE FOR ZYGOMATICOMAXILLARY COMPLEX BONE FRACTURE

Objective: The aim of this study was to investigate the biomechanics of the facial skeletal for understanding the buttress after fixation with standard and modified anatomical thin titanium mesh (ATTM) plates by finite element (FE) analysis. Methods: Standard ATTM (SATTM) plate designed as the “L”-shape anticipated to be fixed in the ZMC anterior maxilla and lateral buttress to increase the fixation screw anchoring strength and another modified ATTM (MATTM) plate with a protrusion in the medial side and a slot and barb design in the lateral side to enhance the zygomaticomaxillary/nasomaxillary buttresses and provide precise positioning to the ZMC segments were studied by the FE analysis under masticatory forces with 250[Formula: see text]N. Result: The FE simulation results indicated that the total displacement distribution of the maxillary for ZMC fracture fixation with MATTM plate was smaller than that of SATTM plate. Stress concentration was found at the frontal and alveolar processes of the maxillary bone for SATTM plate fixation. Local vector plots of the first principal stress near the frontal process of the maxillary and zygomaticofacial formen of the zygomatic indicated that the stress flow for MATTM plate fixation was relatively close to nasomaxillary buttress, and the zygomaticomaxillary buttress, respectively. Conclusions: This study concluded that “L”-shape ATTM plate designed with a protrusion in the medial side and a slot and barb design in the lateral side can enhance the zygomaticomaxillary/nasomaxillary buttresses under uniform occlusal condition.