Comparing Sugarbaker versus keyhole mesh technique for open retromuscular parastomal hernia repair: study protocol for a registry-based randomized controlled trial

BackgroundParastomal hernia, common after stoma creation, negatively impacts patient quality of life. For patients with a permanent stoma, durable parastomal hernia repair remains a challenge, with few high-quality studies for guidance. An alternative to open retromuscular parastomal hernia repair with retromuscular “keyhole” mesh is the recent Sugarbaker modification. We aim to compare these two techniques in a head-to-head prospective study.MethodsThis is a registry-based randomized controlled trial designed to investigate whether the retromuscular Sugarbaker technique is superior to the retromuscular keyhole technique for parastomal hernia repair. The primary study endpoint is parastomal hernia recurrence at two years. Secondary endpoints include hospital length-of-stay, readmission, wound morbidity, mesh-related complications, re-operation, all 30-day morbidity, and patient-reported outcomes, including hernia-related quality of life, stoma-specific quality of life, pain, and decision regret.DiscussionBased on the post hoc analysis of a recent randomized controlled trial, we hypothesize that the retromuscular Sugarbaker technique will reduce parastomal hernia recurrence by 20% at 2 years compared to the retromuscular keyhole mesh technique. The results of this study may provide evidence-based guidance for surgeons repairing parastomal hernias.Trial registrationClinicalTrials.gov NCT03972553. Registered June 3, 2019.

OV18 ENDOSCOPIC RETRO-MUSCULAR REPAIR OF PARASTOMAL HERNIA - A TANTALIZING NEW TECHNIQUE

Development of retro muscular space with transversus abdominis release has reached maturity in endoscopic surgery. Next-level reconstruction is adaptation to parastomal hernia repair alone or in conjunction with another abdominal wall hernia repair. We aim to present this extraperitoneal modified mesh technique based on the Sugarbaker principle with video demonstration and share clinical data and results from twenty-four patients operated with this technique within two years from the spring of 2019 to the spring of 2021. 77% patients had para-colostomy hernia and 41% of the patients had accessory repairs for midline or opposite flank hernia. 18% had prophylactic mesh at index operation, 27% were recurrent parastomal hernia and ostomies were formed median 32 months prior to parastomal hernia repair. 72% of the patients were operated robotically and 28% laparoscopically. Median follow up at time for presentation will be 17 months.

Development of Physics-Based Morphology Model with an Emphasis on the Interaction of Incoming Waves with Transient Bed Profile due to Scouring and Accretion using Dynamic Mesh

A physics-based morphology model [Seoul Foam] was developed using the dynamic mesh technique to explain the interaction between the sea bed, which undergoes deformation due to siltation and scouring, and the incoming waves. In doing so, OlaFlow, an Open Foam-based toolbox, was used as a hydrodynamic model. To verify the proposed physically-based morphology [Seoul Foam] in this study, numerical simulations of the shoaling process over the beach of the uniform slope were implemented. The numerical result shows that the formation process of a sand bar over the foreshore was successfully simulated. As can be easily anticipated, the size of the sand bar was closely linked to the nature of incoming waves, and in the case of a rough sea, the foreshore slope was rapidly deformed due to scouring. In mild seas, several sand waves were formed near the shoreline, and when the exposure time was the same, the size of the sand waves was not as large as in rough seas.

Investigation on Resistance, Squat and Ship-Generated Waves of Inland Convoy Passing Bridge Piers in a Confined Waterway

The average and unsteady hydrodynamics of an inland convoy passing bridge piers in a confined waterway were investigated using both numerical and experimental approaches. The numerical simulations are realized by solving the RANS (Reynolds-averaged Navier–Stokes) equations accounting for the solid body motion using the sliding mesh technique, while the experiments were carried out in the towing tank. The advancing resistance, trim, sinkage and ship-generated waves were analyzed as functions of the water depth, distance between bridge piers, draught and velocity. The existence of the piers is found to only influence the transient hydrodynamics of the convoy, but not the averaged properties. The ship-generated waves, especially the wave profiles at a specific lateral position, were characterized. Two wave crests exist at the pier position because of the additional reflections, creating a very complex wave pattern in the confined waterway.

EP.TH.108A Descriptive Case Series of Incisional Hernia Repair Using Dual Mesh Technique

Aims Incisional hernias are a common complication after surgery that cause significant patient morbidity. Symptomatic patients are offered repair but many surgical techniques exist, with abdominal wall reconstruction becoming preferable for large complex defects. This paper describes our experience of abdominal wall reconstruction using a dual mesh technique. Method 22 patients underwent incisional hernia repair between March 2019 and September 2020. All patients received dual mesh, placed in retrorectus or transversalis fascial/retromuscular space. Absorbable BIO-A GORE mesh was used with a polypropylene mesh above. All patients were followed up to assess for complications and recurrence. Results No patients experienced fistula formation, long-term pain or obstructive symptoms. We report one true hernia recurrence (4.5%) and one case of infected mesh (4.5%), these both await further treatment. One patient had a proven wound infection which resolved with conservative treatment. 4 patients (18.2%) experienced seromas, 3 of these resolved spontaneously, one requiring image-guided drainage. Conclusion Incisional hernia repair using combination polypropylene and bio-absorbable mesh provides a safe and effective repair with low recurrence and incidence of surgical site occurrences in the short term. Longer follow up and further studies are needed to evaluate this mesh technique to support ongoing use of absorbable meshes in complex hernia repair.

Numerical Simulation of Depth Tracking Control of an Underwater Towed System Coupled with Wave–Ship Interference

This paper presents a numerical study of the depth tracking control for an underwater towed system under wave–ship interference condition. To overcome the laminations of ignoring the hydrodynamic factors and wave–ship interference in the existing simulation model for the depth tracking operation of the underwater towed system, a numerical model combining the control system with the computational fluid dynamics (CFD) method based on the overset mesh technique is explored and constructed; the influence of towing ship and head waves is introduced into the numerical analysis of the underwater towed system; a depth control system based on the center of gravity adjustment is proposed and its control characteristics are discussed. The fluid motion around the towed vehicle and the towing ship is governed by the Navier–Stokes equations, and the overset mesh technique is applied for the numerical solution of the equations. The towing cable connecting the towed vehicle and towing ship is governed by the quasi-steady-state catenary equations. The depth tracking controller adjusting the longitudinal position of a shifting weight is constructed based on the proportional–integral–derivative (PID) algorithm. The simulation results show that the numerical simulation system is practicable, and the depth tracking control system is feasible, effective, and robust.

Flow pulsation reduction of a single-piston piezoelectric pump based on elastic cavity group and unloading valve

A piston piezoelectric (PZT) pump has many advantages for the use of light actuators. How to deal with the contradiction between the piston amount and oil delivery quality is an essence when designing the pump. In order to depress the pressure pulsation and flow pulsation in a single-piston PZT pump, a two-stage attenuator is proposed. It involves an elastic cavity group and an unloading valve. Unsteady flow inside the pump is numerically calculated and analyzed to reveal its delivery characteristic in the whole pumping cycle. The distributing process of the passive valves is obtained through the dynamic mesh technique. Influences of key design and operation factors on the delivery performance of the pump are analyzed. The results indicate that the flexible cavity group and the unloading valve arranged at the delivery port can reduce the flow pulsation by 45%. The design can effectively provide stable flow for the actuator in a certain frequency range.

Investigation of the characteristics of turbulent flow and heat transfer induced by a vibrating piezoelectric fan on asymmetrical concave surfaces

This paper aims at performing an investigation numerically on the turbulent flow and thermal performances for an asymmetrical concave surface integrated with a slim vibrating piezoelectric fan. The dynamic mesh technique using a user defined function to describe the displacement function of vibrating cantilever beam is employed to model the deformation of the slim piezoelectric fan in time. Meanwhile, the SST k-ω turbulence model is chosen to capture the turbulence behavior of the flow and heat transfer. Two important factors, the relative curvature of the both sides of semicircular surfaces ( RK) and the dimensionless distance of fan offset along y-axis (Δ y/ APP) are taken into considerations during the simulation process. A considerable increase of local time-average heat transfer coefficients is observed in the vicinity of vibration envelope. The results show that the relative curvature ( RK) has a strong influence on the flow and heat transfer at both ends of the asymmetrical concave surface when its value is larger than 2. And by adjusting the dimensionless offset distance of the piezoelectric fan (Δ y/ APP), the area-averaged convective heat transfer coefficient can be increased by 20% on a small zone surrounding the fan with WPF × App (S1). The conclusions of this paper implement a theoretical attempt for expanding the application scenarios of piezoelectric fan.