Usefulness of an optical tracking system in laparoscopic surgery for motor skills assessment.

INTRODUCTION: The objective of this study is to assess the usefulness of an evaluation system of surgical skills based on motion analysis of laparoscopic instruments. METHOD: This system consists of a physical laparoscopic simulator and a tracking and assessment system of technical skills in laparoscopy. Six surgeons with intermediate experience (between 1 and 50 laparoscopic surgeries) and 5 experienced surgeons (more than 50 laparoscopic surgeries) took part in this study. All participants were right-handed. The subjects performed 3 repetitions of a cutting task on synthetic tissue with the right hand, dissection of a gastric serous layer, and a suturing task in the dissection previously done. Objective metrics such as time, path length, speed of movements, acceleration and motion smoothness were analyzed for the instruments of each hand. RESULTS: In the cutting task, experienced surgeons show less acceleration (P=.014) and a smoother motion (P=.023) using the scissors. Regarding the dissection activity, experienced surgeons need less time (P=.006) and less length with both instruments (P=.006 for dissector and P=.01 for scissors). In the suturing task, experienced surgeons require less time (P=.037) and distance travelled (P=.041) by the dissector. CONCLUSIONS: This study shows the usefulness of the evaluation system for the cutting, dissecting, and suturing tasks. It represents a significant step in the development of advanced systems for training and assessment of surgical skills in laparoscopic surgery.

Optimising Bioprinting Nozzles through Computational Modelling and Design of Experiments.

3D bioprinting is a promising technique for creating artificial tissues and organs. One of the main challenges of bioprinting is cell damage, due to high pressures and tensions. During the biofabrication process, extrusion bioprinting usually results in low cell viability, typically ranging from 40% to 80%, although better printing performance with higher cell viability can be achieved by optimising the experimental design and operating conditions, with nozzle geometry being a key factor. This article presents a review of studies that have used computational fluid dynamics (CFD) to optimise nozzle geometry. They show that the optimal ranges for diameter and length are 0.2 mm to 1 mm and 8 mm to 10 mm, respectively. In addition, it is recommended that the nozzle should have an internal angle of 20 to 30 degrees, an internal coating of ethylenediaminetetraacetic acid (EDTA), and a shear stress of less than 10 kPa. In addition, a design of experiments technique to obtain an optimal 3D bioprinting configuration for a bioink is also presented. This experimental design would identify bioprinting conditions that minimise cell damage and improve the viability of the printed cells.