Richard Goossens

Assessment of the Ergonomically Optimal Operating Surface Height for Laparoscopic Surgery

PURPOSEnThe aim of this study was to find the ergonomically optimal operating surface height for laparoscopic surgery in order to reduce discomfort in the upper extremities of the operators and the assistants. The operating surface height was defined as the level of the abdominal wall of a patient with pneumoperitoneum.nnnMATERIALS AND METHODSnTwo pelvi-trainer tests were performed. One test was performed on six different operating surface heights. The (extreme) joint excursions of the shoulder, elbow, and wrist were measured by a video analysis method. Another test was performed by holding a laparoscope for 15 minutes while an electromyelograph of the biceps brachii was made. The results of both tests were evaluated subjectively by a questionnaire.nnnRESULTSnThe ergonomically optimal operating surface height lies between a factor 0.7 and 0.8 of the elbow height of the operator/assistant. At this height, the joint excursions stay in the neutral zone for more than 90% of the total manipulation time, and the activity of the biceps brachii when holding the laparoscope stays within 15% of the maximum muscle activity.nnnCONCLUSIONSnThe operating surface height influences the (extreme) upper joint excursions of the surgeon. The ergonomically optimal operating surface height reduces the discomfort in the shoulders, back, and wrists of the surgeon during laparoscopic surgery. This optimal table height range for laparoscopic surgery is lower than those currently available.

Ergonomic problems encountered by the medical team related to products used for minimally invasive surgery

Background: The aim of this study is to gain insight into the problems encountered by the medical team related to products used for minimally invasive surgery.Methods: An inventory was made of the problems encountered during 12 endoscopic operations performed in one city hospital (Eindhoven, the Netherlands). After the observation, a questionnaire was distributed to all medical staff involved. Results: All categories of personnel had physical, perceptional, and cognitive problems, especially surgeons, residents, and the sterile operation nurse. The main causes were the positioning of apparatus and staff, work clothing, and the limited reach of apparatus and/or instruments. Of the questionnaires, 80% were returned: 50% of the medical staff experienced perceptional problems and 63% had physical discomfort during the surgical procedure. Conclusion: The diversity of problems observed and/or reported by the staff during minimally invasive surgery decrease the comfort, efficiency, and safety of the operating-room work environment. Therefore, a new design approach is needed for MIS products in order to address the problems that occur with the current equipment.

New ergonomic design criteria for handles of laparoscopic dissection forceps.

BACKGROUNDnThe shape of laparoscopic instrument handles can cause physical discomfort. This problem may be ascribed to a lack of standards for instrument design. In this study, new ergonomic requirements for the design of laparoscopic dissection forceps were created. Three representative handles (a Karl Storz [click-line] scissors handle, an Access Plus scissors handle, and an Aesculap cylindrical handle) currently available on the market were evaluated according to the new list of ergonomic criteria.nnnMATERIALS AND METHODSnThe handles were subjectively (questionnaire) and objectively (video analyses) tested in order to find out whether the new requirements are valid for the evaluation and design of instrument handles.nnnRESULTSnThe outcome of the subjective and objective tests matched the predictions by the new criteria list. New criteria were introduced (neutral wrist excursions), and existing general criteria were specified (e.g., a minimal contact area of 10 mm). Significant differences were found among the three handles. The Storz handle met 8 of the 10 requirements, the Access handle met 5, and the Aesculap handle met only 4.nnnCONCLUSIONSnThe new list of ergonomic requirements is a valid tool to determine the ergonomic value of a handle for laparoscopic dissecting tasks. It gains its strength from its specialized character. Significant differences were found among the three tested handles. Cylindrical handles were inferior to scissors handles.

Design criteria for the reduction of shear forces in beds and seats

Both with respect to the aspect of pressure sores and of comfort, the inclination of backrest and seat are, amongst other factors, important design criteria. In this study the combination of seat and backrest inclination which reduces shear forces on the seat in passive seating forms the centre of attention. A biomechanical model was developed to predict these combinations and a new measurement apparatus was used for verification of the model on 10 healthy subjects (age 24.4 S.D. 2.1 yr, height 1.77 S.D. 0.08 m, mass 66.3 S.D. 11 Kg). For chairs it was found that when little shear is accepted, a fixed inclination between seat and backrest can be chosen between 90 degrees and 95 degrees. For beds a parabolic relationship was found between seat and backrest inclination with a maximum seat inclination of 20 degrees at a backrest inclination of 50 degrees. When lying with the knees bent to a position with equal inclination of thighs and shanks, the model predicts a shear force on the seat that shoves the person into the bed for every combination of seat and backrest inclination.

Design for (every)one: Co-creation as a bridge between universal design and rehabilitation engineering

Design for (every)one is a macro framework that attempts to identify, share and use ‘hidden solutions’ in community-based rehabilitation contexts and translate them into disruptive assistive devices built with local resources or appropriate technology. Within healthcare contexts, local solutions are frequently more effective as they reflect the physical, emotional and cognitive needs of specific patients and engage all stakeholders in a specific local context. By using open horizontal innovation networks, where assistive devices can be easily shared and physically hacked by other allied health professionals, general patterns can be detected and translated into standard universal design objects. This generative design thinking approach is more than feasible with digital trends such as crowd sourcing, user-generated content and peer production. Cheap and powerful prototyping tools have become easier to use by non-engineers; it turns them into users as well as self-manufacturers of their personal assistive artefacts. This paper discusses the different aspects of this open innovation process within a ‘design for disability’ context and suggests the first steps in an iterative co-design methodology that brings together expertise from professional designers, occupational therapists, patients and other stakeholders. The overall aim is to gain more insights into designing qualitative occupational experiences for disabled users.

Decubitus Risk: Is Shear More Important than Pressure?

A mechanical load through which the capillaries are closed causes tissue ischaemia of the skin. Most authors agree that it is this tissue ischaemia that is the main factor in the cause of pressure sores. Different combinations of mechanical load on the skin may have the same effect within the skin. The aim of this study is to evaluate the effect that different combinations of pressure and shear have on blood flow within the skin. The skin blood flow was measured by means of skin oxygen tension. Different load combinations on the skin surface, for which the maximum shear stress within the skin remained equal, showed no significant difference in skin blood flow. Research should therefore focus on load situations within the skin instead of pressure measurements on the skin surface only.

Learning from Aviation to Improve Safety in the Operating Room - a Systematic Literature Review

Lessons learned from other high-risk industries could improve patient safety in the operating room (OR). This review describes similarities and differences between high-risk industries and describes current methods and solutions within a system approach to reduce errors in the OR. PubMed and Scopus databases were systematically searched for relevant articles written in the English language published between 2000 and 2011. In total, 25 articles were included, all within the medical domain focusing on the comparison between surgery and aviation. In order to improve safety in the OR, multiple interventions have to be implemented. Additionally, the healthcare organization has to become a ‘learning organization’ and the OR team has to become a team with shared responsibilities and flat hierarchies. Interpersonal and technical skills can be trained by means of simulation and can be supported by implementing team briefings, debriefings and cross-checks. However, further development and research is needed to prove if these solutions are useful, practical, and actually increase safety.

Medical emergency dynamics in disaster-prone countries – implications for medical device design

Emergency medical services and surgery are an essential part of the local response to natural and humanitarian disasters. The aim of this study is to identify performance obstacles regarding the use of medical devices in medical emergencies. The case study, conducted in the Dr. Sardjito General Hospital in Indonesia, entails semi-structured interviews with surgeons from the Orthopaedics and Traumatology Department, as well as exploratory observations in the emergency and operating rooms. A literature-based reporting tool, observable performance obstacles (OPO), was designed and tested. The results demonstrate that data collection through observation yields rich insights that are relevant to the literature on human factors, and to the applied field of user-centred design. This experience also reveals the inherent difficulty of doing research in the dynamic setting of medical emergencies. As a result, several changes to the OPO are proposed for its application in follow-up projects.

High Risks of High Backrests

When designing office chairs and wheelchairs, most attention is paid to geometry to adjust chairs to individual body dimensions. The aim of this study is to gain insight in biomechanical sound design criteria for the backrest. Out of a biomechanical model and tests on a healthy population it was concluded that free shoulder space of at least 6 cm is needed when designing a backrest for a wheelchair. And when focussing at the inclination of the backrest, an opening angle between seat and backrest of 90° degrees is wanted.When designing office chairs and wheelchairs, most attention is paid to geometry to adjust chairs to individual body dimensions. The aim of this study is to gain insight in biomechanical sound design criteria for the backrest. Out of a biomechanical model and tests on a healthy population it was concluded that free shoulder space of at least 6 cm is needed when designing a backrest for a wheelchair. And when focussing at the inclination of the backrest, an opening angle between seat and backrest of 90° degrees is wanted.