BACKGROUND: Intra-abdominal pressure (IAP) is a critical parameter in the care of critically ill patients, as elevated IAP can lead to reduced cardiac output and organ perfusion, potentially resulting in multiple organ dysfunction and failure. The current gold standard for measuring IAP is an indirect technique via the bladder. According to the Abdominal Compartment Society\'s Guidelines, new measurement methods/devices for IAP must be validated against the gold standard.
OBJECTIVE: This study introduces Ventra, an abdominal phantom designed to simulate different IAP levels, abdominal compliance, respiration-related IAP variations, and bladder dynamics. Ventra aims to facilitate the development and validation of new IAP measurement devices while reducing reliance on animal and cadaveric studies. Additionally, it offers potential applications in training and education for biomedical engineering students. This study provides a thorough explanation on the phantom\'s design and fabrication, which provides a low-cost solution for advancing IAP measurement research and education. The design concept, technical aspects, and a series of validation experiments determining whether Ventra is a suitable tool for future research are presented in this study.
METHODS: Ventra\'s performance was evaluated through a series of validation tests using a pressure gauge and two intra-gastric (Spiegelberg and CiMON) and two intra-bladder (Accuryn and TraumaGuard) pressure measurement devices. The mean and standard deviation of IAP recordings by each device were investigated. Bland-Altman analysis was used to evaluate bias, precision, limits of agreement, and percentage error for each system. Concordance analysis was performed to assess the ability of Ventra in tracking IAP changes.
RESULTS: The phantom demonstrated excellent agreement with reference pressure measurements, showing an average bias of 0.11 ± 0.49 mmHg. A concordance coefficient of 100% was observed for the phantom as well. Ventra accurately simulated different abdominal compliances, with higher IAP values resulting in lower compliance. Abdominal volume changes showed a bias of 0.08 ± 0.07 L/min, and bladder fill volume measurements showed an average difference of 0.90 ± 4.33 mL for volumes ranging from 50 to 500 mL.
CONCLUSIONS: The validation results were in agreement with the research guidelines of the world abdominal society. Ventra is a reliable tool that will facilitate the development and validation of new IAP measurement devices. It is an effective educational tool for biomedical engineering students as well.

BACKGROUND: The reporting of randomised controlled non-inferiority (NI) drug trials is poor with less than 50% of published trials reporting a justification of the NI margin. This is despite the introduction of the Consolidated Standards of Reporting Trials (CONSORT) extension on reporting of NI and equivalence in randomised trials. It is critical to set the appropriate NI margin as this choice dictates the conclusions of the trial. Methods to estimate the margin are heterogeneous but generally based on clinical judgement and statistical reasoning, and hence tailored to each clinical situation. Yet an appraisal of NI in clinical trials has not been undertaken. Therefore the aim of this systematic review is to assess the reporting and methodological quality of defining the NI margin. Surgical NI trials have been chosen as our prototype to assess this.
METHODS: We will conduct a systematic review of published randomised controlled trials in abdominal surgery that use an NI design. Key eligibility criteria will be: surgical intervention in at least one trial arm; adult patients and a sample size of 100 or more. Ovid MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials will be searched from inception until the date of the search. Identified studies will be assessed for reporting according to the CONSORT recommendations. The outcomes are the description of the methods for defining the NI margin, and the robustness of the NI margin estimation. The latter will be based on simulations using alternative assumptions for model parameters. The results of the simulation will be compared with the trial authors\' conclusions.
RESULTS: The review will describe and appraise the design and reporting of surgical NI trials including shortcomings thereof and allow a comparison with pharmaceutical trials. These findings will inform researchers on the appropriate design and pitfalls when conducting surgical randomised controlled trials with an NI design and promote thorough and standardised reporting of study findings.
BACKGROUND: Ethical approval is not required and any changes to the protocol will be communicated via the registration platform. The final manuscript will be submitted to a journal for publication and the findings will be disseminated through conference presentations to inform researchers and the public.

The X-rays emitted during CT scans can increase solid cancer risks by damaging DNA, with the risk tied to patient-specific organ doses. This study aims to establish a new method to predict patient specific abdominal organ doses from CT examinations using minimized computational resources at a fast speed. The CT data of 247 abdominal patients were selected and exported to the auto-segmentation software named DeepViewer to generate abdominal regions of interest (ROIs). Radiomics feature were extracted based on the selected CT data and ROIs. Reference organ doses were obtained by GPU-based Monte Carlo simulations. The support vector regression (SVR) model was trained based on the radiomics features and reference organ doses to predict abdominal organ doses from CT examinations. The prediction performance of the SVR model was tested and verified by changing the abdominal patients of the train and test sets randomly. For the abdominal organs, the maximal difference between the reference and the predicted dose was less than 1 mGy. For the body and bowel, the organ doses were predicted with a percentage error of less than 5.2%, and the coefficient of determination (R2) reached up to 0.9. For the left kidney, right kidney, liver, and spinal cord, the mean absolute percentage error ranged from 5.1 to 8.9%, and the R2 values were more than 0.74. The SVR model could be trained to achieve accurate prediction of personalized abdominal organ doses in less than one second using a single CPU core.

BACKGROUND: The neurological, airway, respiratory, cardiovascular and other, with a subscore of surgical severity (NARCO-SS) is a scoring system which assesses the presence of systemic disease and the risk the operation poses to the patient. A number of patients that undergo major abdominal surgery suffer adverse events. The aim of the study was to determine the reliability of NARCO-SS in predicting peri-operative adverse events and to determine the risk factors for peri-operative adverse events in paediatric patients undergoing elective abdominal surgery.
METHODS: Prospective cohort study. Consecutively sampled patients from December 2019 to December 2020 were used. Patients scheduled for elective abdominal surgery were scored pre-operatively and end points were; when an adverse event occurred or up to day 30. Analysis of the reliability of the tool, bivariate and multivariate logistics regression was done.
RESULTS: One hundred and nineteen patients were enrolled and 49% of them had adverse events. Both bivariate and multivariate analyses showed no significant association between the NARCO-SS score and the occurrence of adverse events. The area under the receiver operating characteristics curve (area under the curve) of the NARCO-SS for adverse events was 0.518; there was a significant correlation between high scores and mortality. Longer duration of surgery and complex surgery were the risk factors for adverse events.
CONCLUSIONS: The NARCO-SS score was found to be a poor predictor of adverse events with a fair inter-rater reliability as a scoring tool. Future research could evaluate a modification of neurological and airway categories.

We present a case of a 31-year-old male who presented to the emergency department with a history of abdominal pain localized to the lower abdomen. The patient had undergone splenectomy 2 years ago for splenic injury following a road traffic accident. Computerized tomography showed multiple well-defined, homogeneously enhancing soft tissue density nodules of varying sizes distributed throughout the abdomen and pelvis. A diagnosis of splenosis was made based on imaging findings and history. Abdominal splenosis is an uncommon entity of which radiologists need to be aware, and this case serves to shed further light on this condition.

UNASSIGNED: Disseminated peritoneal leiomyomatosis (DPL) is a rare benign disease, characterized by intraperitoneal dissemination of smooth-muscle tumor masses.
METHODS: The patient, a 40-year-old, female - presented with complaints of periodic back pain. During the initial workup, a tumor mass was visualized in the pelvis on ultrasound. Further clinical workup included computer tomography (CT) scan and ultrasound-guided fine-needle biopsy. A tumor mass in the right adrenal gland was identified on CT. Pathological examination revealed no signs of malignancy. The multidisciplinary team decided on surgical treatment. Tumor masses were removed from the pelvic cavity, the anterior abdominal wall, and the projection of the right adrenal gland with preservation of the uterus and ovaries due to the patient\'s wishes. Pathological examination with immunohistochemistry of surgical specimen confirmed diagnosis of DPL.
UNASSIGNED: Due to the rarity of DPL there are no standard guidelines for diagnostics and treatment. In many cases, on initial workup, DPL may look like a malignant tumor with intraperitoneal spread, which may lead to an inappropriate choice of treatment.
CONCLUSIONS: Differential diagnosis of DPL may be a challenge due to its appearance as a disseminated peritoneal malignancy on CT scans and at laparotomy. A multidisciplinary approach is key to choosing the right clinical course for such patients.

High dose-rate brachytherapy is a treatment technique for gynecologic cancers where intracavitary applicators are placed within the patient\'s pelvic cavity. To ensure accurate radiation delivery, localization of the applicator at the time of insertion is vital. This study proposes a novel method for acquiring, registering, and fusing three-dimensional (3D) trans-abdominal and 3D trans-rectal ultrasound (US) images for visualization of the pelvic anatomy and applicators during gynecologic brachytherapy. The workflow was validated using custom multi-modal pelvic phantoms and demonstrated during two patient procedures. Experiments were performed for three types of intracavitary applicators: ring-and-tandem, ring-and-tandem with interstitial needles, and tandem-and-ovoids. Fused 3D US images were registered to magnetic resonance (MR) and computed tomography (CT) images for validation. The target registration error (TRE) and fiducial localization error (FLE) were calculated to quantify the accuracy of our fusion technique. For both phantom and patient images, TRE and FLE across all modality registrations (3D US versus MR or CT) resulted in mean ± standard deviation of 4.01 ± 1.01 mm and 0.43 ± 0.24 mm, respectively. This work indicates proof of concept for conducting further clinical studies leveraging 3D US imaging as an accurate, accessible alternative to advanced modalities for localizing brachytherapy applicators.

BACKGROUND: The utility of preoperative abdominal ultrasonography (US) in evaluating patients with obesity before metabolic bariatric surgery (MBS) remains ambiguously defined.
METHODS: Retrospective analysis whereby patients were classified into four groups based on ultrasound results. Group 1 had normal findings. Group 2 had non-significant findings that did not affect the planned procedure. Group 3 required additional or follow-up surgeries without changing the surgical plan. Group 4, impacting the procedure, needed further investigations and was subdivided into 4A, delaying surgery for more assessments, and 4B, altering or canceling the procedure due to critical findings. Machine learning techniques were utilized to identify variables.
RESULTS: Four thousand four hundred eighteen patients\' records were analyzed. Group 1 was 45.7%. Group 2, 35.7%; Group 3, 17.0%; Group 4, 1.5%, Group 4A, 0.8%; and Group 4B, 0.7%, where surgeries were either canceled (0.3%) or postponed (0.4%). The hyperparameter tuning process identified a Decision Tree classifier with a maximum tree depth of 7 as the most effective model. The model demonstrated high effectiveness in identifying patients who would benefit from preoperative ultrasound before MBS, with training and testing accuracies of 0.983 and 0.985. It also showed high precision (0.954), recall (0.962), F1 score (0.958), and an AUC of 0.976.
CONCLUSIONS: Our study found that preoperative ultrasound demonstrated clinical utility for a subset of patients undergoing metabolic bariatric surgery. Specifically, 15.9% of the cohort benefited from the identification of chronic calculous cholecystitis, leading to concomitant cholecystectomy. Additionally, surgery was postponed in 1.4% of the cases due to other findings. While these findings indicate a potential benefit in certain cases, further research, including a cost-benefit analysis, is necessary to fully evaluate routine preoperative ultrasound\'s overall utility and economic impact in this patient population.

UNASSIGNED: Abdominal surgery is considered a high-risk procedure for the development of surgical site infection (SSI). Few studies have evaluated the relative importance of surgical site infection risk factors in terms of consistency in abdominal surgery. Therefore, this comprehensive review article mapped and summarized the evidence aimed to determine the relative importance of the risk factors and incidence of SSIs in abdominal surgery.
UNASSIGNED: A literature review was conducted using electronic databases and search engines such as Scopus, PubMed, and Web of Science up to March 16, 2023. There was no language restriction for the papers to be included in the study. The relative consistency of the risk factors was measured and evaluated using the methodology of the Joanna Briggs Institute. Original peer-reviewed cohort and case-control studies were included if all types of SSIs were included. Meta-analysis was performed to determine the pooled estimates of SSI incidences.
UNASSIGNED: Of 14,237 identified records, 107 articles were included in the review. The pooled incidence of SSI was 10.6% (95% CI: 9.02-12.55%, χ2=12986.44, P<0.001). Operative time and higher wound class were both significant consistent risk factors for SSI incidence. Patients\' educational status, malnutrition, functional status, and history of neurological/psychiatric disorders were all candidates for consistent risk factors, with insufficient evidence.
UNASSIGNED: The findings of the present study indicated that SSI in abdominal surgery was a multifactorial phenomenon with a considerable risk and had different risk factors with various relative importance. Determining the relative importance of the risk factors for the prevention and control of SSI is strongly recommended.This manuscript has been released as a preprint at the research square: (https://doi.org/10.21203/rs.3.rs-3219597/v1).

UNASSIGNED: This study aimed to examine the feasibility of the dovetailing skin incision design of radial forearm free flap (RFFF) for closing forearm wounds and performing maxillofacial reconstruction.
UNASSIGNED: A total of 27 patients were divided into two groups. In the dovetail group (n = 16), forearm wounds were closed primarily and maxillofacial defects were reconstructed by dovetail RFFF. In the conventional group (n = 11), forearm wounds were closed by skin grafts from the abdomen or mattress suturing, and maxillofacial defects were reconstructed by conventional RFFF. Information on the healing time of the forearm wound, length of postsurgical hospitalization, esthetic assessments, and complications associated with the forearm wound and the maxillofacial region was collected at least 6 months postoperatively.
UNASSIGNED: The average size of the flap in the dovetail group was smaller than that in the conventional group (p = 0.134), and average healing time of the forearm wound in dovetail group was significantly shorter than that in conventional group (p = 0.000). Comparing with the conventional group, there were more cases in the dovetail group demonstrating decreased sensitivity (p = 1.000). Esthetic assessments of forearm wound and maxillofacial reconstructions in the dovetail group were significantly higher than that in the conventional group (p = 0.000).
UNASSIGNED: Closure of forearm wounds and maxillofacial defects using dovetail design was found to be a feasible alternative to the conventional design.