TY - JOUR T1 - Tissue stress from laparoscopic grasper use and bowel injury in humans: establishing intraoperative force boundaries JF - BMJ Surgery, Interventions, & Health Technologies DO - 10.1136/bmjsit-2021-000084 VL - 3 IS - 1 SP - e000084 AU - Amanda Farah Khan AU - Matthew Kenneth MacDonald AU - Catherine Streutker AU - Corwyn Rowsell AU - James Drake AU - Teodor Grantcharov Y1 - 2021/07/01 UR - http://sit.bmj.com/content/3/1/e000084.abstract N2 - Objectives We aim to determine what threshold of compressive stress small bowel and colon tissues display evidence of significant tissue trauma during laparoscopic surgery.Design This 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.Setting An inner-city trauma and ambulatory hospital with a 40-bed inpatient general surgery unit with a diverse patient population.Participants Patients 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.Interventions A 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.Results Small 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.Conclusions A 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.Data are available in a public, open access repository. All files and schematics used to create the PrecisionCAT is freely available on Harvard’s Dataverse Repository at the following URL: https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/Q0WOEZ. Code Availability: All custom Python code created and used in the preparation of this manuscript is freely available on Github. The PrecisionCAT data is available, freely to the public at the following URL: https://github.com/crushdevice. ER -