Temperature profile and residual heat of monopolar laparoscopic and endoscopic dissection instruments

Background Endoscopic and laparoscopic electrosurgical devices (ED) are of great importance in modern medicine but can cause adverse events such as tissue injuries and burns from residual heat. While laparoscopic tools are well investigated, detailed insights about the temperature profile of endoscopic knives are lacking. Our aim is to investigate the temperature and the residual heat of laparoscopic and endoscopic monopolar instruments to increase the safety in handling ED. Methods An infrared camera was used to measure the temperature of laparoscopic and endoscopic instruments during energy application and to determine the cooling time to below 50 °C at a porcine stomach. Different power levels and cutting intervals were studied to investigate their impact on the temperature profile. Results During activation, the laparoscopic hook exceeded 120 °C regularly for an up to 10 mm shaft length. With regards to endoknives, only the Dual Tip Knife showed a shaft temperature of above 50 °C. The residual heat of the laparoscopic hook remained above 50 °C for at least 15 s after activation. Endoknives cooled to below 50 °C in 4 s. A higher power level and longer cutting duration significantly increased the shaft temperature and prolonged the cooling time (p < 0.001). Conclusion Residual heat and maximum temperature during energy application depend strongly on the chosen effect and cutting duration. To avoid potential injuries, the user should not touch any tissue with the laparoscopic hook for at least 15 s and with the endoknives for at least 4 s after energy application. As the shaft also heats up to over 120 °C, the user should be careful to avoid tissue contact during activation with the shaft. These results should be strongly considered for safety reasons when handling monopolar ED.

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.

A Smart Laparoscopic Instrument with Different Applications

The main target of everyone engineering work associated with minimally-invasive surgery is to provide adequate tool-tissue force information to the surgeons so that they can regain the sense of touch that has been lost through laparoscopic surgery. In this context the main objective of the work design novel family laparoscopic tools with better technical characteristics, and incorporation of force and other sensors and elements in construction of tools for restore sense of touch in the process of laparoscopy. Thus it is improving some technical side of this laparoscopic instruments. In contrast to daVinchi robots by Intuitive Surgical Incorporation which instruments are designed for manipulation and imaging we offer family tools with additional functions such as diagnosis and therapeutics tasks. Therefore we decide two main problems: i) we designed and produced an original construction of an adequate experimental module for robots, where was incorporated two force sensors to provide tool-tissue information (some of which was described and discussed at previous works); and ii) we realized hardware and program resources for control and monitoring of this module which is the object of this work. The computer program includes information about various measurements of the tip tool – surface contact interactions and data obtained from the experimental module that is used to find the difference between date from previous measuring and received information in real time. Another signification advantage of the proposed program solution is the graphical visualization of the measuring and comparing the results. Therefore, the surgeon can give the adequate command to force interaction between the instrument and tissue. For verification of the functionality and working capacity of the experimental module with force feedback capabilities for robots were conducted different experiments with the designed control system.

Long-term successful closure of a percutaneous intragastric trocar tract with crossing full-thickness sutures in a porcine model

Background and study aims A novel intragastric trocar placed using a percutaneous endoscopic gastrostomy technique enables the use of laparoscopic tools and procedures, including tissue stapling, cutting, suturing, and retraction. The aim of this porcine study was to determine long-term success of crossing full-thickness sutures in closure of the tract upon trocar withdrawal. Methods 10 trocars were placed in 5 animals. Each animal underwent a standardized tissue resection using a 5-mm stapler under gastroscopic guidance, and two full-thickness, absorbable, crossing sutures were used to close the trocar tracts. The animals were monitored for 35 days and then euthanized for necropsy. Results All five animals survived without sign of infection or distress. Nine of the 10 trocar sites healed completely without any adverse findings. A single site developed a gastrocutaneous fistula. On necropsy, there was no evidence of intra-abdominal infection or abscess. Conclusions Full-thickness crossing sutures appeared to be effective in long-term closure of an intragastric trocar tract. Given the ease of placement and success of this simple closure method, this device may prove clinically useful to the endoscopist performing complex procedures in the endoscopy suite.

A Comparative Assessment of Novel Mini-Laparoscopic Tools

Background: Mini-laparoscopy, or needlescopy, is an emerging minimally invasive technique that aims to improve on standard laparoscopy in the areas of tissue trauma, pain, and cosmesis. The objective of this study was to determine if there was a difference in functionality between 2 novel mini-laparoscopic instruments when compared to standard laparoscopic tools. Differences were assessed in a simulated surgical environment. Methods: Twenty participants (5 novices, 10 intermediate, 5 expert) were recruited for this institutional review board–approved study in a surgical simulation training center. Group A tools were assembled intracorporeally, and Group B tools were assembled extracorporeally. Using standard laparoscopic graspers, mini-laparoscopic graspers, or a combination of both, each participant performed 3 basic laparoscopic training tasks: a Peg Transfer, Rubber Band Stretch, and Tootsie Roll Unwrapping. Following each round of tasks, participants completed a survey evaluating the mini-laparoscopic graspers with respect to standard laparoscopic graspers. Data were analyzed using Kruskal-Wallis test with Dunn’s test for post hoc comparisons. Results: When comparing task times, both mini tools performed at the level of standard laparoscopic graspers in all participant groups. Group A tools were quicker to assemble and disassemble versus Group B tools. According to posttask surveys, all participant groups indicated that both sets of mini-laparoscopic graspers were comparable to the standard graspers. Conclusion: In a nonclinical setting, mini-laparoscopic instruments perform at the level of standard laparoscopic tools. Based on these results, clinical trials would be a reasonable next step in assessing feasibility and safety.