Tissue stress from laparoscopic grasper use and bowel injury in humans: establishing intraoperative force boundaries

ObjectivesWe aim to determine what threshold of compressive stress small bowel and colon tissues display evidence of significant tissue trauma during laparoscopic surgery.DesignThis study included 10 small bowel and 10 colon samples from patients undergoing routine gastrointestinal surgery. Each sample was compressed with pressures ranging from 100 kPa to 600 kPa. Two pathologists who were blinded to all study conditions, performed a histological analysis of the tissues. Experimentation: November 2018–February 2019. Analysis: March 2019–May 2020.SettingAn inner-city trauma and ambulatory hospital with a 40-bed inpatient general surgery unit with a diverse patient population.ParticipantsPatients were eligible if their surgery procured healthy tissue margins for experimentation (a convenience sample). 26 patient samples were procured; 6 samples were unusable. 10 colon and 10 small bowel samples were tested for a total of 120 experimental cases. No patients withdrew their consent.InterventionsA novel device was created to induce compressive “grasps” to simulate those of a laparoscopic grasper. Experimentation was performed ex-vivo, in-vitro. Grasp conditions of 0–600 kPa for a duration of 10 s were used.ResultsSmall bowel (10), M:F was 7:3, average age was 54.3 years. Colon (10), M:F was 1:1, average age was 65.2 years. All 20 patients experienced a significant difference (p<0.05) in serosal thickness post-compression at both 500 and 600 kPa for both tissue types. A logistic regression analysis with a sensitivity of 100% and a specificity of 84.6% on a test set of data predicts a safety threshold of 329–330 kPa.ConclusionsA threshold was discovered that corresponded to both significant serosal thickness change and a positive histological trauma score rating. This “force limit” could be used in novel sensorized laparoscopic tools to avoid intraoperative tissue injury.

Tissue Stress from Laparoscopic Grasper Use and Bowel Injury in Humans: Establishing Intraoperative Force Boundaries

BackgroundInappropriate force in laparoscopic surgery can lead to inadvertent tissue injury. It is currently unknown however at what magnitude of compressive stress trauma occurs in gastrointestinal tissues.MethodsThis study included 10 small bowel and 10 colon samples. Each was compressed with pressures ranging from 100 kPa to 600 kPa by a novel device to induce compressive “grasps” to simulate those of a laparoscopic grasper. Experimentation was performed ex-vivo, in-vitro. Grasp conditions of 0 to 600 kPa for a duration of 10 seconds were utilized. Two pathologists who were blinded to all study conditions, performed a histological analysis of the tissues. Patients were eligible if their surgery procured healthy tissue margins for experimentation (a convenience sample). 26 patient samples were procured; six samples were unusable. 10 colon and 10 small bowel samples were tested for a total of 120 experimental cases. No patients withdrew their consent. Two metrics of damage were quantified: an intestinal layer thickness calculation where the serosa layer was measured in the area of compression and compared to a local control and a histological scoring scale for tissue trauma.ResultsSmall bowel (10), M:F was 7:3, average age was 54.3 years. Colon (10), M:F was 1:1, average age was 65.2 years. All 20 patients experienced a significant difference (p<0.05) in serosal thickness post-compression at both 500 and 600 kPa for both tissue types. A logistic regression analysis with a sensitivity of 100% and a specificity of 84.6% on a test set of data predicts a safety threshold of 329-330 kPa.ConclusionA threshold was discovered that corresponded to both significant serosal thickness change and a positive histological trauma score rating. This “force limit” could be used in novel sensorized laparoscopic tools to avoid intraoperative tissue injury.

EXTERNAL PRINGLE MANEUVER IN LAPAROSCOPIC LIVER RESECTION: A SAFE, CHEAP AND REPRODUCIBLE WAY TO PERFORM IT

ABSTRACT Background: Laparoscopic liver resection is performed worldwide. Hemorrhage is a major complication and bleeding control during hepatotomy is an important concern. Pringle maneuver remains the standard inflow occlusion technique. Aim: Describe an extracorporeal, efficient, fast, cheap and reproducible way to execute the Pringle maneuver in laparoscopic surgery, using a chest tube. Methods: From January 2014 to March 2020, our team performed 398 hepatectomies, 63 by laparoscopy. We systematically encircle the hepatoduodenal ligament and prepare a tourniquet to perform Pringle maneuver. In laparoscopy, we use a 24 Fr chest tube, which is inserted in the abdominal cavity through a small incision. We thread the cotton tape through the tube, pulling it out through the external end, outside the abdomen. To perform the tourniquet, we just need to push the tube as we hold the tape, clamping both with one forceps. Results: The 24 Fr chest tube is firm and works perfectly to occlude blood inflow as the cotton band is tightened. It has an internal diameter of 5,5 mm, sufficient for a laparoscopic grasper pass through it to catch the cotton band, and an external diameter of 8 mm, which allows to be inserted in the abdomen through a tiny incision. The cost of this tube and the cotton band is less than US$ 1. No complications related to the method were identified in our patients. Conclusions: The extracorporeal Pringle maneuver presented here is a safe, cheap and reproducible method, that can be used for bleeding control in laparoscopic liver surgery.

Performance of a Haptic Feedback Grasper in Laparoscopic Surgery: A Randomized Pilot Comparison With Conventional Graspers in a Porcine Model

Background. Compared with open surgery, minimally invasive surgery is limited by reduced sensation of tissue properties. A laparoscopic grasper with integrated haptic feedback technology that improves the ability to sense tissue properties might provide a solution. The force reflecting operation instrument (FROI) is a new laparoscopic grasper, designed to provide information about the interaction forces between the instrument and tissue through resistance in the handle. This pilot study aimed to assess the functionality of the FROI compared with a conventional grasper in an in vivo setting. Methods. In this randomized trial, we used a standard laparoscopic surgical setup to perform laparoscopic surgery in pigs. In all, 11 surgeons performed colorectal, gynecological, or urological procedures, once with the FROI and once with a conventional grasper. Participants were asked to complete the NASA Task Load Index Rating Scale and rate 5 specific features for both graspers. To capture opinions on the overall functionality of the FROI, participants were asked to answer 8 open questions. Results. The surgeons reported that the use of the FROI significantly improved tissue consistency perception, arterial pulse detection, and force control compared with the conventional grasper. No significant differences were found in surgeons’ muscular strain or operative time. The most emphasized topics in the open questions were improved soft-tissue handling and importance for complex procedures. Conclusion. Through this first in vivo analysis of the functionality of the FROI, a multispecialty group of laparoscopic surgeons confirmed the added value of haptic feedback technology in a live surgical setting.

Estimation of Friction Force in Minimally Invasive Surgery with Tactile Sensors

This study investigates coefficient of friction of flat-tipped laparoscopic surgery tool (bowel grasper) in an ex vivo experiment in order to identify the approximate coefficient of friction between laparoscopic tool and the organic sample. The estimation of friction force is essential for ensuring safe grasping. The friction tribometer and the laparoscopic grasper setup were the two experimental setups to conclude the friction of the tool in the absence tactile sensor. The measurement of the pinch force and estimation of the friction force from the measured pinch force and the coefficient of friction is suitable for novice surgeon training.

An Ergonomic Customized-Tool Handle Design for Precision Tools using Additive Manufacturing: A Case Study

A study was carried out with 135 surgeons to obtain a surgical laparoscopic grasper handle design that adapts to the size of each surgeon’s hand, in a functionally appropriate way, and has the sufficient ergonomics to avoid generating the problems detected nowadays. The main conclusion of the work is the practical 3D parametric design obtained for a laparoscopic surgical graspers handle that is scalable to fit each particular surgeon's hand size. In addition, it has been possible to determine that the anthropometric measure of the surgeon's hand defined as Palm Length Measured (PLM) allows the design of the 3D parametric model of the surgical handle to be conveniently scaled. The results show that both additive manufacturing and the application of ergonomics criterion provide an efficient method for the custom design and manufacture of this type of specialised tool, with potential application in other sectors.