Dirk W. Meijer

Laparoscopic resection of colon Cancer: consensus of the European Association of Endoscopic Surgery (EAES).

BackgroundThe European Association of Endoscopic Surgery (EAES) initiated a consensus development conference on the laparoscopic resection of colon cancer during the annual congress in Lisbon, Portugal, in June 2002.MethodsA systematic review of the current literature was combined with the opinions, of experts in the field of colon cancer surgery to formulate evidence-based statements and recommendations on the laparoscopic resection of colon cancer.ResultsAdvanced age, obesity, and previous abdominal operations are not considered absolute contraindications for laparoscopic colon cancer surgery. The most common cause for conversion is the presence of bulky or invasive tumors. Laparoscopic operation takes longer to perform than the open counterpart, but the outcome is similar in terms of specimen size and pathological examination. Immediate postoperative morbidity and mortality are comparable for laparoscopic and open colonic cancer surgery. The laparoscopically operated patients had less postoperative pain, better-preserved pulmonary function, earlier restoration of gastrointestinal function, and an earlier discharge from the hospital. The postoperative stress response is lower after laparoscopic colectomy. The incidence of port site metastases is <1%. Survival after laparoscopic resection of colon cancer appears to be at least equal to survival after open resection. The costs of laparoscopic surgery for colon cancer are higher than those for open surgery.ConclusionLaparoscopic resection of colon cancer is a safe and feasible procedure that improves short-term outcome. Results regarding the long-term survival of patients enrolled in large multicenter trials will determine its role in general surgery.

Stress response to laparoscopic surgery: a review

BackgroundLaparoscopic surgery is associated with reduced surgical trauma, and therefore with a less acute phase response, as compared with open surgery. Impairment of the immune system may enhance surgical infections, port-site metastases, and sepsis. The objectives of this review was to assess immunologic consequences of benign laparoscopic surgery and to highlight controversial aspects.MethodsA literature search on stress response to nonmalignant laparoscopic and open surgery was conducted using the MEDLINE and Cochrane databases. Cross-references from the reference list of major articles on the subject were used, as well as manuscripts published between 1993 and 2002.ResultsLocal (i.e., peritoneal) immune function is affected by carbon dioxide pneumoperitoneum. The production of tumor necrosis factor and the phagocytotic capacity of peritoneal macrophages are less lowered. The systemic stress response, as determined by delayed-type hypersensitivity response and leukocyte antigen expression on lymphocytes, shows a preservation of immune function after laparoscopic surgery, as compared with conventional surgery.ConclusionsIntraperitoneal carbon dioxide insufflation attenuates peritoneal immunity, but laparoscopic surgery is associated with a lower systemic stress response than open surgery.

Assessment of the Ergonomically Optimal Operating Surface Height for Laparoscopic Surgery

PURPOSE The 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. MATERIALS AND METHODS Two 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. RESULTS The 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. CONCLUSIONS The 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.

New ergonomic design criteria for handles of laparoscopic dissection forceps.

BACKGROUND The 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. MATERIALS AND METHODS The 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. RESULTS The 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. CONCLUSIONS The 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.

Theoretical background and conceptual solution for depth perception and eye-hand coordination problems in laparoscopic surgery

SummaryThe indirect method of observation and manipulation in laparoscopic surgery complicates the surgeons depth perception and impairs his/her eye-hand coordination. Depth perception problems are due to misfits in accommodation and convergence, absence of shadows in endoscopic camera pictures and absence of stereo-vision and movement parallax. Eye-hand coordination problems are caused by the distant location of the monitor and by the fact that the surgeons hand movements are rotated, mirrored and amplified when they appear on the monitor. These effects are very confusing, especially for trainee laparoscopic surgeons and require a long and intensive training period to overcome. This paper gives a theoretical background of the depth perception and eye-hand coordination problems. A technical concept of an endoscope positioning system is described that compensates misorientations by using a flexible 90° endoscope. Movement parallax is achieved using a motorised endoscope positioner controlled by the surge...

Evaluation of the usability of two types of image display systems, during laparoscopy

BackgroundThis study was performed to assess the optimal display location of a flat-screen monitor for laparoscopy. It was also performed to assess the posture (objective), opinion, and preference (subjective) of subjects using a flat-screen monitor positioned in the optimal display location and a cathode-ray tube monitor on a tower next to the operating table (current situation).MethodsTwelve surgeons performed cholecystectomies using the two display systems alternately. The postures of the operator and the assistant were assessed by an infrared video analysis system.ResultsThe posture of the assistant is significantly better when using a flat-screen monitor [more neutral head flexions (p=0.036) and neutral neck torsions (p=0.012)]. No significant differences were found for the posture of the operator. The operators and assistants felt more comfortable when using a flat-screen monitor (p=0.008) and they preferred this display to the use of a monitor on a tower.ConclusionsThe use of flat-screen monitors is better for the physical and psychological comfort of the users, even though the technical performance is inferior in comparison with that of regular monitors.

Improvement of the laparoscopic needle holder based on new ergonomic guidelines

Background: The aim of this study is to create new ergonomic guidelines for the design of laparoscopic needle holders. Methods: An ergonomic literature study, observations in the operating room, handle–shaft angle measurements, and anthropometric data were used to compile new ergonomic criteria, specified to the function of a laparoscopic needle holder. Based on these guidelines a new needle holder was designed. The prototype and three currently available needle holders were evaluated according to the new guidelines. In addition, a pelvi-trainer test was done to measure the extreme wrist excursions. Results: The ergonomic evaluation of three commonly used handles and the new prototype indicate that the new handle is an ergonomic improvement in the field of laparoscopic needle holders: only the new handle satisfies all criteria. This is validated by the results of the pelvi-trainer test, which showed that the new prototype significantly (p < 0.001) reduced the extreme wrist excursions. Conclusion: The new design guidelines for a laparoscopic needle holder result in an ergonomic improvement of the instrument.

Current state of ergonomics of operating rooms of Dutch hospitals in the endoscopic era

Laparoscopic procedures are mostly performed in operating rooms which have been designed for conventional surgery. The ergonomic layout of these operating rooms is not suited for endoscopic surgery. This study reports on the current state of ergonomics of Dutch operating rooms for laparoscopic surgery. Number of trolleys, presence of ceiling‐mounted booms, and number, positioning and size of monitors were recorded. The floor surface of operating rooms and lowest and highest positions of operating tables were documented. Positioning of the surgical team and monitors during laparoscopic surgery were assessed. Twenty‐nine hospitals participated in this study. The average number of trolleys per hospital was 2.4. The mean height of the center of the monitors was 163 cm. Average floor surface of operating rooms was 37.45 m 2 . Only one of the 29 hospitals had a ceiling‐mounted boom. The height of operating tables varied between 725 and 1215 mm. The floor space of current operating rooms is too small to allow use of space occupying technological systems. Less than 4% of operating rooms are equipped with permanent monitors mounted on booms. Operating tables cannot be lowered to a position which allows an ergonomic posture of the surgical team.

Development of a scheme which visualizes the human-product interaction in minimally invasive surgery

The aim of this study is to visualize in a scheme all factors that are part of or influence the human-product interaction in minimally invasive surgery (MIS). The factors involved in the interaction are identified and investigated by means of literature studies, product information from producers and retailers, and by observation of MIS procedures. An interaction scheme has been compiled which encompasses the following factors: A product factor, divided into the surgical functions of image visualization, workspace creation, tissue treatment, tissue assessment, and procedure support. A human factor, divided into the functions of perception, cognition, and action. Internal factors (perceptional, cognitive, and action) and external factors (social, political, physical, clinical, and technological) that influence the interaction. Two product examples are used to demonstrate the use of the interaction scheme. The results show that when the design of a product focuses on limited factors, problems arise related to those factors which are not considered. The interaction scheme is a new way to represent the human-product interaction in MIS. It can be used to structure and to gain insight into problems that occur with the use of MIS products. The scheme also elucidates the factors that are involved in the interaction so that they can be considered in product and operating room design.