Bernadette McCrory

Quality and Safety of Minimally Invasive Surgery: Past, Present, and Future

Adverse events because of medical errors are a leading cause of death in the United States (US) exceeding the mortality rates of motor vehicle accidents, breast cancer, and AIDS. Improvements can and should be made to reduce the rates of preventable surgical errors because they account for nearly half of all adverse events within hospitals. Although minimally invasive surgery (MIS) has proven patient benefits such as reduced postoperative pain and hospital stay, its operative environment imposes substantial physical and cognitive strain on the surgeon increasing the risk of error. To mitigate errors and protect patients, a multidisciplinary approach is needed to improve MIS. Clinical human factors, and biomedical engineering principles and methodologies can be used to develop and assess laparoscopic surgery instrumentation, practices, and procedures. First, the foundational understanding and the imperative to transform health care into a high-quality and safe system is discussed. Next, a generalized perspective is presented on the impact of the design and redesign of surgical technologies and processes on human performance. Finally, the future of this field and the research needed to further improve the quality and safety of MIS is discussed.

Ergonomic evaluation of laparoendoscopic single-site surgery ports in a validated laparoscopic training model

Although laparoendoscopic single-site surgery (LESS) is feasible among expert laparoscopic surgeons, it poses many technical challenges not seen in conventional laparoscopy (CL). Recent technological advancements in single-incision instrumentation have created more interest and widespread usage of LESS. However, neither LESS nor its novel instrumentation have been thoroughly studied or evaluated using human factors and ergonomics techniques. Consequently, the aim of this study was to compare the physical performance of LESS to CL using a standardized task. Wrist and elbow angular movements, range of motion and physical discomfort were assessed for 24 novice participants. There were no significant differences for physical comfort/discomfort ratings or elbow and wrist flexion/extension range of motion between CL and LESS. However, wrist radial/ulnar range of motion was significantly greater in LESS compared to CL (p < 0.05). Additionally, wrist radial/ ulnar range of motion was significantly greater using the SILS Port compared to the GelPOINT (p < 0.05). Although further investigation is needed, LESS resulted in greater wrist deviation and range of motion due to the close proximity of the instruments, restrictive nature of the single-port devices, and the need to achieve adequate instrument triangulation and visualization.

Comparative Usability Testing of Conventional and Single Incision Laparoscopic Surgery Devices

Objective: The objective was to perform competitive usability testing to assess the user experience of conventional laparoscopic and laparoendoscopic single-site surgery (LESS) devices. Background: Recent advancements in single-incision instrumentation have created more interest in and usage of LESS. However, neither LESS nor its novel multichannel access devices have been thoroughly studied. Method: Using a simulation test bed and standardized laparoscopic surgery task, the user experience of three commercially available LESS devices was compared to conventional laparoscopic ports based on time on task, errors, task success, and perceived ease of use. Results: There were no significant differences between devices for time on task, errors, or task success (p > .05). For all devices, there were significantly more recoverable than unrecoverable errors, and errors occurred more frequently during the second phase of the task when the dominant hand was more active (p < .0001). Conventional laparoscopy was rated as easier to use than were the LESS devices (p < .01). Conclusion: Device performance of a basic laparoscopic task was similar in both conventional laparoscopy and LESS. Each of the LESS devices facilitated efficient and accurate aiming and grasping movements compared to conventional laparoscopy. Further investigation of human factors and ergonomics of LESS is needed to further develop, evaluate, and refine single-site surgery technologies to create a user experience equivalent to conventional laparoscopy. Application: Competitive usability testing of medical devices yields objective performance data that can be used to inform purchase decisions and future device design improvements.

A Preliminary Study of Novice Workload and Performance During Surgical Simulation Tasks for Conventional vs. Single Incision Laparoscopic Techniques

Laparoendoscopic single site surgery (LESS) can provide potential patient benefits beyond conventional laparoscopy (CL). However, LESS further exacerbates current ergonomic disadvantages of CL. LESS practices to compensate for the constraints include intracorporeal crossing of instruments (UL) for improved manipulation of instrumentation and extracorporeal crossing of hands (PL) for illusion mitigation. Preliminary results from this study involving 12 medical students (7 males) performing a simulated surgical task found statistical difference between CL, PL, and UL for physical demand (P<0.001), task complexity (P=0.002) and performance times (P<0.001) with no difference for mental demand (P=0.106). These initial findings show that the PL technique cannot currently compensate for the limitations of LESS to make UL more similar to CL. Further research is needed to determine if PL or another LESS compensatory practice can allow surgeons to more effectively perform procedures with a single port and therefore ensure patients reap its benefits.

Task analysis method for procedural training curriculum development

AbstractA central venous catheter (CVC) is an important medical tool used in critical care and emergent situations. Integral to proper care in many circumstances, insertion of a CVC introduces the risk of central line-associated blood stream infections and mechanical adverse events; proper training is important for safe CVC insertion. Cognitive task analysis (CTA) methods have been successfully implemented in the medical field to improve the training of postgraduate medical trainees, but can be very time-consuming to complete and require a significant time commitment from many subject matter experts (SMEs). Many medical procedures such as CVC insertion are linear processes with well-documented procedural steps. These linear procedures may not require a traditional CTA to gather the information necessary to create a training curriculum. Accordingly, a novel, streamlined CTA method designed primarily to collect cognitive cues for linear procedures was developed to be used by medical professionals with minimal CTA training. This new CTA methodology required fewer trained personnel, fewer interview sessions, and less time commitment from SMEs than a traditional CTA. Based on this study, a streamlined CTA methodology can be used to efficiently gather cognitive information on linear medical procedures for the creation of resident training curricula and procedural skills assessments.

Workload comparison of IntraOral mask to standard mask ventilation using a cadaver model

Background: The bag-valve mask (BVM) is critical to providing positive pressure ventilation for patients who are not breathing or who are breathing inadequately. This simple hand-held device enables healthcare professionals to quickly provide mechanical ventilation in emergent and non-emergent situations. However, the difficulty of achieving and maintaining an adequate seal between the BVM and face reduces ventilation volume and the success rate of resuscitation efforts. A novel IntraOral Mask (IOM) was developed by NuMask to eliminate these difficulties by creating a seal inside the mouth using a snorkel-like mouthpiece. There have been no published reports comparing the human factors and ergonomics of these masks. Therefore, the aim of this study was to compare the perceived workload of the standard BVM and the NuMask IOM. Method: Twenty-five emergency medicine students performed mechanical ventilation on a cadaver model using both masks. Workload was assessed using the NASA-TLX after ventilating with each mask. Results: Overall workload and effort were rated significantly less for the IOM (p < 0.05). In general, the IOM had lower median ratings for physical demand, mental demand and frustration compared to the BVM. Conclusion: Overall, the IOM appears to facilitate gripping through its novel snorkel-like design and reduced hand interface size by decreasing the perceived effort and workload of the healthcare responder. However, further clinical and ergonomic investigations are needed to ascertain whether the IOM improves mechanical ventilation performance and therefore resuscitation success rates.

Single-Site Laparoscopic Nephrectomy: Is It Cost-Effective?

Background: With the emergence of Laparoendoscopic Single-Site Surgery (LESS) and its potential patient benefits, a cost comparison was conducted to enable informed decision-making for the selection of minimally invasive surgical approach type for nephrectomy. Methods: A literature-based cost comparison of Hand-Assisted Laparoscopic (HAL), Conventional Laparoscopic (LAP), and LESS nephrectomies was conducted to determine whether the benefits of LESS offset the expense of this new technique and its expensive technologies. Using institutional rates the total cost of each approach was determined by summing the costs of instrumentation unique to each approach, Operative Time (OT) and patient length of stay (LOS). One-way and two-way sensitivity analyses were performed varying each of the costs to determine cost-equivalence thresholds across the approaches. Results: Based on the literature review (n=557), LESS was the most cost effective due to short OT and LOS. OT would have to be less than 121 and 145 minutes or LOS would have to be less than 1.5 and 2.86 days for HAL and LAP to be more cost-effective than LESS, respectively. Conclusion: The cost difference between LAP and LESS was minimal and small decreases in OT, LOS or both would result in a cost-advantage for LAP. Although LESS was the most economical approach, this preliminary cost analysis was based on the procedural outcomes of expert surgeons that were early-adopters of LESS. Prospective, controlled trials comparing HAL, LAP and LESS are critical for procedural optimization and cost control.

Hand Instrument Performance in A Single Site Surgery Simulator With Novices

Laparoendoscopic single-site surgery (LESS) is a new minimally invasive surgical technique that presents physical and mental challenges to surgeons. Currently, LESS procedures are commonly performed using surgical instruments designed for traditional multi-incision laparoscopic surgery. A pilot study was conducted to determine which laparoscopic instruments were the most efficient for LESS procedures. In a LESS surgical trainer, 24 novice users completed a simple surgical task using standard (non-articulating) straight laparoscopic graspers and two different articulating instruments. Task performance was scored based on completion time and the number of errors. Analyses showed that the use of the simpler straight instruments produced significantly faster times (p = 0.004 and p = 0.014) and higher task scores (p = 0.005 and p = 0.021) than the articulating instruments. These results suggest that standard laparoscopic hand instruments enable better novice performance for a basic LESS task.

Comparison of Muscle Exertion and Fatigue Between Standard Bag Valve Mask and NuMask

Ventilation is an important part of cardiopulmonary resuscitation (CPR) performed by medical professionals. The self-inflating bag valve mask (BVM) is often used to deliver rescue breaths during CPR. As resuscitation may last for extended periods of time, it is important that the equipment used reduces the potential of operator fatigue, which could lead to decreased performance and substandard patient care. The NuMask is an intraoral mask designed as an alternative to the pre-inflated mask typically used with a BVM. This pilot study uses muscle exertion electromyography, Borg’s CR10 pain scale, and a Likert-scale questionnaire to compare muscle contraction, fatigue, and user preference between these two interfaces when ventilating a difficult airway mannequin. No significant differences were found in muscle pain or interface preference, but significantly lower muscular exertion by the non-dominant thenar eminence when using the NuMask suggests this interface could reduce user fatigue during extended periods of ventilation. A larger, more conclusive study is necessary to confirm these results.