The influence of prolonged instrument manipulation on gas leakage through trocars.

BACKGROUND: During laparoscopic surgery, CO2 insufflation gas could leak from the intra-abdominal cavity into the operating theater. Medical staff could therefore be exposed to hazardous substances present in leaked gas. Although previous studies have shown that leakage through trocars is a contributing factor, trocar performance over longer periods remains unclear. This study investigates the influence of prolonged instrument manipulation on gas leakage through trocars. METHODS: Twenty-five trocars with diameters ranging from 10 to 15 mm were included in the study. An experimental model was developed to facilitate instrument manipulation in a trocar under loading. The trocar was mounted to a custom airtight container insufflated with CO2 to a pressure of 15 mmHg, similar to clinical practice. A linear stage was used for prolonged instrument manipulation. At the same time, a fixed load was applied radially to the trocar cannula to mimic the reaction force of the abdominal wall. Gas leakage was measured before, after, and during instrument manipulation. RESULTS: After instrument manipulation, leakage rates per trocar varied between 0.0 and 5.58 L/min. No large differences were found between leakage rates before and after prolonged manipulation in static and dynamic measurements. However, the prolonged instrument manipulation did cause visible damage to two trocars and revealed unintended leakage pathways in others that can be related to production flaws. CONCLUSION: Prolonged instrument manipulation did not increase gas leakage rates through trocars, despite damage to some individual trocars. Nevertheless, gas leakage through trocars occurs and is caused by different trocar-specific mechanisms and design issues.

Pre-clinical evaluation of the new veress needle+ mechanism on thiel-embalmed bodies: a controlled crossover study - Experimental research.

Veress needles (VN) are commonly used in establishing pneumoperitoneum in laparoscopic surgery. Previously, a VN with a new safety mechanism 'VeressPLUS' needle (VN+) was developed to reduce the amount of overshoot. Methods: Eighteen participants (novices, intermediates, and experts) performed in total of 248 insertions in a systematic way on Thiel-embalmed bodies with wide and small bore versions of the conventional VN (VNc) and the VN+. Insertion depth was measured by recording the graduations on the needle under direct laparoscopic vision. Results: Participants graded the bodies and the procedures as lifelike. Overall, a significant reduction (P<0.001) in average insertion depth was found for the VN+ compared to the VNc of 26.0 SD16 mm versus 46.2 SD15 mm. The insertion depth difference in the novice group was higher compared to the intermediates and experts (P<0.001). The average insertion depth for both needle types was less (P<0.001) for female participants compared to male. Conclusion: This study indicated that the VN+ significantly reduced the insertion depth in all tested conditions. Whether the difference between female and male performance can be linked to differences in muscle control or arm mass should be further investigated. Useful technical information was gathered from this study to further improve the VN+.

The Compressiometer: Toward a New Skin Tensiometer for Research and Surgical Planning.

After surgery, around 35% of patients experience problems of excessive scarring, causing disfiguring and impaired function. An incision placed in the wrong direction causes unnecessary skin tension on the wound, resulting in increased collagen disposition and potentially hypertrophic scars. Currently, skin tension lines are used for incision planning. However, these lines are not universal and are a static representation of the skin tension that is in fact under influence of muscle action. By designing a new skin force measurement device the authors intend to make research on dynamic skin characteristics possible and to objectify incision planning and excision closure planning. The device applies a known compressive force to the skin in standardized directions and measures the displacement of the skin. This allows users to measure the skin reaction force in response to compression and to determine the optimal incision line or best wound closure direction. The device has an accuracy of 96% and a sensitivity of < 0.01 mm. It is compact, works non-invasively and standardizes measurement directions and is therefore an improvement over previously designed skin tensiometers.

Assessment of laparoscopic instrument reprocessing in rural India: a mixed methods study.

BACKGROUND: Laparoscopy is a minimally-invasive surgical procedure that uses long slender instruments that require much smaller incisions than conventional surgery. This leads to faster recovery times, fewer post-surgical wound infections and shorter hospital stays. For these reasons, laparoscopy could be particularly advantageous to patients in low to middle income countries (LMICs). Unfortunately, sterile processing departments in LMIC hospitals are faced with limited access to equipment and trained staff which poses an obstacle to safe surgical care. The reprocessing of laparoscopic devices requires specialised equipment and training. Therefore, when LMIC hospitals invest in laparoscopy, an update of the standard operating procedure in sterile processing is required. Currently, it is unclear whether LMIC hospitals, that already perform laparoscopy, have managed to introduce updated reprocessing methods that minimally invasive equipment requires. The aim of this study was to identify the laparoscopic sterile reprocessing procedures in rural India and to test the effectiveness of the sterilisation equipment. METHODS: We assessed laparoscopic instrument sterilisation capacity in four rural hospitals in different states in India using a mixed-methods approach. As the main form of data collection, we developed a standardised observational checklist based on reprocessing guidelines from several sources. Steam autoclave performance was measured by monitoring the autoclave cycles in two hospitals. Finally, the findings from the checklist data was supported by an interview survey with surgeons and nurses. RESULTS: The checklist data revealed the reprocessing methods the hospitals used in the reprocessing of laparoscopic instruments. It showed that the standard operating procedures had not been updated since the introduction of laparoscopy and the same reprocessing methods for regular surgical instruments were still applied. The interviews confirmed that staff had not received additional training and that they were unaware of the hazardous effects of reprocessing detergents and disinfectants. CONCLUSION: As laparoscopy is becoming more prevalent in LMICs, updated policy is needed to incorporate minimally invasive instrument reprocessing in medical practitioner and staff training programmes. While reprocessing standards improve, it is essential to develop instruments and reprocessing equipment that is more suitable for resource-constrained rural surgical environments.

A novel Veress needle mechanism that reduces overshooting after puncturing the abdominal wall.

BACKGROUND: Complications that occur in laparoscopic surgery are often associated with the initial entry into the peritoneal cavity. The literature reported incidences of Veress needle (VN) injuries of e.g. 0.31% and 0.23%. In a 2010 national survey of laparoscopic entry techniques in the Canadian General Surgical practice, 57.3% of respondents had either experienced or witnessed a serious laparoscopic entry complication like bowel perforation and vascular injury. As those complications are potentially life threatening and should be avoided at all costs, improving safety of this initial action is paramount. METHODS: Based on a bare minimum design approach with focus on function expansion of existing components, a new Safety mechanism was developed for the VN that decreases the risks of VN overshooting. The mechanism works by preventing the puncturing acceleration of the tip of the VN by decoupling the surgeon's hand from the VN immediately after entering the abdomen. RESULTS: Based on a set of requirements, a first prototype of the VN+ with force decoupling safety mechanism is presented and evaluated on an ex vivo porcine abdominal wall tissue model in a custom setup. The experiments conducted by two novices and one experienced surgeon indicated a significant difference between the attempts with a standard, conventional working VN (41.4 mm [37.5-45 mm]) and VN+ with decoupling mechanism (20.8 mm [17.5-22.5 mm]) of p < 0.001. CONCLUSION: A new decoupling safety mechanism was integrated successfully in a standard VN resulting in a VN+ . The results from the pilot study indicate that this new VN+ reduces overshooting with a minimum of 50% in a standardised ex vivo setting on fresh porcine abdominal wall specimens.

Lethal smothering with a pillow - How 181 music festival visitors tried to kill a dummy.

PURPOSE: Smothering to death is most often done with a soft cover, such as a pillow. This is one of the hardest to diagnose causes of death. Knowing more about how people perform such an act and whether there is any correlation between perpetrator characteristics and smothering approaches may help in solving criminal cases involving smothering. METHODS: A total of 181 visitors of a music festival were asked to smother a dummy with a pillow. Each participant provided their age, gender, dominant hand, length, weight, alcohol use (last 24h) and drug use (last 24h) in a questionnaire. Forces applied by the participant on the dummy head with the pillow were continuously measured and the smothering modus operandi (described by aspects such as the placement of the hands, feet and body weight) was obtained from video recordings. RESULTS: Participants with high alcohol consumption provided higher smothering forces. Increases were also found for taller participants and those who had used drugs. Smothering seemed most effective when placing both hands on the pillow on the head and when placing the center of mass as much directly above the dummy head as possible. A stable, central stance also benefitted smothering effectiveness. CONCLUSION: Forensic case work may potentially benefit from these results in the future by linking the current results to the location of hand and finger marks on a pillow.

Force measurement metrics for simulated elbow arthroscopy training.

BACKGROUND: Elbow arthroscopy is a difficult surgical technique. Objective metrics can be used to improve safe and effective training in elbow arthroscopy. Force exerted on the elbow tissue during arthroscopy can be a measure of safe tissue manipulation. The purpose of this study was to determine the force magnitude and force direction used by experts during arthroscopic elbow navigation in cadaveric specimens and assess their applicability in elbow arthroscopy training. METHODS: Two cadaveric elbows were mounted on a Force Measurement Table (FMT) that allowed 3-dimensional measurements (x-, y-, and z-plane) of the forces exerted on the elbow. Five experts in elbow arthroscopy performed arthroscopic navigation once in each of two cadaveric elbows, navigating through the posterior, posterolateral and anterior compartment in a standardized fashion with visualization of three to four anatomic landmarks per compartment. The total absolute force (Fabs) and force direction exerted (α and ß) on the elbow during arthroscopy were recorded. α being the angle in the horizontal plane and ß being the angle in the vertical plane. The 10th-90th percentiles of the data were used to set threshold levels for training. RESULTS: The median Fabs was 24 N (19 N - 30 N), 27 N (20 N - 33 N) and 29 N (23 N - 32 N) for the posterior, posterolateral and anterior compartment, respectively. The median α was - 29° (- 55° - 5°), - 23° (- 56° - -1°) and 4° (- 22° - -18°) for the posterior, posterolateral and anterior compartment, respectively. The median ß was - 71° (- 80° - -65°), - 76° (- 86° - -69°) and - 75° (- 81° - -71°) for the posterior, posterolateral and anterior compartment, respectively. CONCLUSION: Expert data on force magnitude and force direction exerted on the elbow during arthroscopic navigation in cadaveric specimens were collected. The proposed maximum allowable force of 30 N (smallest 90th percentile of Fabs) exerted on the elbow tissue, and the 10th-90th percentile range of the force directions (α and ß) for each compartment may be used to provide objective feedback during arthroscopic skills training.