Pancreatic anastomosis training models: Current status and future directions.

Postoperative pancreatic fistula (POPF) is a major cause of morbidity and mortality after pancreatoduodenectomy (PD), and previous research has focused on patient-related risk factors and comparisons between anastomotic techniques. However, it is recognized that surgeon experience is an important factor in POPF outcomes, and that there is a significant learning curve for the pancreatic anastomosis. The aim of this study was to review the current literature on training models for the pancreatic anastomosis, and to explore areas for future research. It is concluded that research is needed to understand the mechanical properties of the human pancreas in an effort to develop a synthetic model that closely mimics its mechanical properties. Virtual reality (VR) is an attractive alternative to synthetic models for surgical training, and further work is needed to develop a VR pancreatic anastomosis training module that provides both high fidelity and haptic feedback.

A Hybrid Method Integrating A Musculoskeletal Model with Long Short-Term Memory (LSTM) for Human Motion Prediction.

So far, it shows a growing interest in the biomechanics community in the development of wearable technologies and their clinical applications, which enables the diagnosis of movement disorders and design of the rehabilitation interventions. To provide reliable feedback in the human-machine interface for advanced rehabilitation devices, methods to predict motion intention was developed which aim to generate future human motion based on the measured motion. An inertial measurement unit (IMU) is a promising device for motion tracking, with the advantages of low cost and high convenience in sensor placement to measure motion in almost every environment. However, it reveals that few contributions have been devoted to human motion prediction with pure IMU data. Thus, we propose a hybrid method integrating a musculoskeletal (MSK) model and the long short-term memory (LSTM) artificial neural network (ANN) to predict human motion. The proposed method was capable to predict motion in the daily tasks (stand-to-sit-to-stand and walking) for healthy participants: the predicted knee joint angles had an RMSE of 2.93° when compared to measured knee joint angles from the IMU data. The proposed method outperformed the methods based on the ANN/MSK model (RMSE of 31.15°) and LSTM without the integration of the MSK model (RMSE of 31.26°) in the motion prediction. Clinical Relevance- This proposed model based on IMU data alone has the great potential to become a low-cost, easy-to-use alternative in motion prediction to interact with advanced rehabilitation devices in clinical practice.

In vitro investigation into the forces involved during lipofilling.

Breast augmentation using implants is the most common aesthetic and reconstructive breast surgical procedure. Complications such as implant rupture maybe related to surgical technique and damage to the implant. Autologous fat transfer (lipofilling) using metallic cannulae has become a standard adjunctive, yet there is little evidence on lipofilling safety in the presence of implants. The aims of this study are to verify the effects of different cannulae and to quantify the forces applied by surgeons during lipofilling. Silicone gel-filled textured implants (200 mL), mounted on a specially constructed mould were ruptured with two different cannulae: type A (hole at tip: sharp) and type B (hole away from tip: blunt), driven at three speeds (10, 100 and 1000 mm/min), and the force at rupture was recorded. In addition, the maximum 10 forces over a 30-s period applied by 11 plastic surgeons against a breast implant in an in vitro environment were recorded using a load cell attached to a type-A cannula. Statistical analysis of comparative results was performed using t-tests, with p < 0.05 considered significant. Results showed that the implant ruptured at forces up to 25% lower when cannula A was used compared to cannula B. This supports current technique in lipofilling in the use of a blunt tipped cannula. There was a significant difference between some displacement rates only, due to the viscoelastic nature of the material. The tactile force that surgeons use during lipofilling was modelled in vitro and showed a range of maximum forces between 0.23 and 16.8 N, with a mean maximum value of 6.9 N. Limitation of this study is that it may not reflect in vivo behaviour of breast implants. More studies are needed to confirm the safety of breast lipofilling in the presence of implants using these data as a starting point.

Design of an improved surgical instrument for the removal of bladder tumours.

The aim of this work was to design an add-on instrument that could potentially decrease the recurrence of non-muscle invasive bladder cancer. The current surgical approach permits spilled tumour cells to disseminate within the bladder, re-implant and cause tumour recurrence. An add-on instrument has been designed in the form of an opening cone intended to provide space for surgery and yet reduce tumour cell spillage and dissemination. A prototype was manufactured using the shape memory metal Nitinol which was activated using an electrical current to facilitate opening and supplemented with latex to provide a sealed environment. The prototype was tested in comparable surgical conditions utilising porcine bladder wall and blue dye to simulate tumour cells. It was demonstrated that the vast majority of dye was retained within the device, supporting the proposed aim.

Development of a transient large strain contact method for biological heart valve simulations.

A new 2D method to implement transient contact using Comsol Multiphysics (finite element analysis software that enables multiphysics simulations) is described, which is based on Hertzian contact. This method is compared to the existing (default) contact method that does not enable real transient simulations, but instead performs steady-state solutions where time is a constant. The two types of contact modelling have been applied to simple 2D biological heart valve models, undergoing strains in the region of 10% under 20 kPa pressure (applied over 0.3 s). Both the methods predicted comparable stress patterns, locations of peak stresses, deformations and directions of principal stress. The default contact method predicted slightly greater contact stresses, but spreads over a shorter surface length than the new contact method. The default contact method is useful for contact systems with little transient dependency, due to ease of use. However, where transient conditions are important the new contact method is preferred.