Search PubMed⌕ Search

Biomedical subjects

D W Meijer

Publications and source records attributed to D W Meijer.

At least 19 recordsLinked to original sources
PubMed2004

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

BACKGROUND: The 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. METHODS: A 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. RESULTS: Advanced 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. CONCLUSION: Laparoscopic 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.

Colectomy↗
PubMed2004

Stress response to laparoscopic surgery: a review.

BACKGROUND: Laparoscopic 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. METHODS: A 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. RESULTS: Local (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. CONCLUSIONS: Intraperitoneal carbon dioxide insufflation attenuates peritoneal immunity, but laparoscopic surgery is associated with a lower systemic stress response than open surgery.

Acute-Phase Reaction↗
PubMed2004

Hand-assisted laparoscopic surgery (HALS): a report of 150 procedures.

BACKGROUND: This study was performed to evaluate the (long-term) morbidity associated with hand-assisted laparoscopic surgery (HALS) for various indications. METHODS: HALS procedures for various indications were evaluated prospectively from 1995 to 2002. The primary outcome parameters were postsurgical complications and the development of incisional hernias. RESULTS: Twenty-six splenectomies, 51 hand-assisted laparoscopic donor nephrectomies (HLDN), 34 segmental bowel resections, 29 proctocolectomies, and 10 emergency colectomies were evaluated. A Küstner or Pfannenstiel incision was used for handport placement. Minor complications (i.e., wound complications, urinary tract infection) occurred in 15%, 12%, 26%, 7%, and 33% of the patients after, respectively, splenectomy, HLDN, bowel resection, proctocolectomy, and emergency colectomy. Major complications (i.e., hemorrhage, anastomotic leakage) occurred in 15% and 12% of the patients after, respectively, bowel resection and proctocolectomy. Incisional hernias occurred in six patients (4%), all after a wound complication in the Küstner incision. CONCLUSION: HALS is fast, safe, and feasible for various indications, especially HLDN and (procto-)colectomies. Little advantage can be expected when HALS is applied in splenectomy and segmental bowel (sigmoid) resection.

Adult↗
PubMed2003

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.

Equipment Design↗
PubMed2003

Safety of the laparoscopy setup.

The safety of the laparoscopy setup is an important issue to guarantee continuous quality of laparoscopic interventions. Important issues are visualization, the insufflator and especially electrosurgery. Appropriate training of the OR personnel and clear responsibilities should be defined. Checklists are advised.

Journal Article↗
PubMed2002

Quantitative evaluation of three advanced laparoscopic viewing technologies: a stereo endoscope, an image projection display, and a TFT display.

BACKGROUND: Compared to open surgery, minimally invasive surgery (MIS) relies heavily on advanced technology, such as endoscopic viewing systems and innovative instruments. The aim of the study was to objectively compare three technologically advanced laparoscopic viewing systems with the standard viewing system currently used in most Dutch hospitals. METHODS: We evaluated the following advanced laparoscopic viewing systems: a Thin Film Transistor (TFT) display, a stereo endoscope, and an image projection display. The standard viewing system was comprised of a monocular endoscope and a high-resolution monitor. Task completion time served as the measure of performance. Eight surgeons with laparoscopic experience participated in the experiment. RESULTS: The average task time was significantly greater (p <0.05) with the stereo viewing system than with the standard viewing system. The average task times with the TFT display and the image projection display did not differ significantly from the standard viewing system. CONCLUSION: Although the stereo viewing system promises improved depth perception and the TFT and image projection displays are supposed to improve hand-eye coordination, none of these systems provided better task performance than the standard viewing system in this pelvi-trainer experiment.

Analysis of Variance↗
PubMed2002

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.

Electromyography↗
PubMed2001

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

BACKGROUND: This 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). METHODS: Twelve 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. RESULTS: The 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. CONCLUSIONS: The 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.

Cholecystectomy↗
PubMed2001

Improved usability of a new handle design for laparoscopic dissection forceps.

BACKGROUND: Recent studies have shown that the shape of most instrument handles causes user discomfort and that none of the handles currently available on the market satisfies all ergonomic criteria. Therefore, we designed a handle with improved usability; i.e., it is easier to manipulate and its use entails less risk of injury for the operator. The aim of this study was to demonstrate that the intended improvements of the new design were successful. METHODS: Six handles representative of the types that are currently available were compared with the new version. Eight surgeons used the seven handles during a precision task and a rough task in a pelvi-trainer. A questionnaire and video analyses were used to assess the usability of the handles. RESULTS: Based on the responses to the questionnaire, we determined that there were significant differences between the new handle and the Aesculap handle (means of rotation and angle between handle and shaft). No significant differences were found between the new handle and the five other handles. The video analyses (documenting extreme vs neutral wrist excursions) showed significant differences between the new handle and the six other handles. CONCLUSION: Compared to the six existing handles, the new handle has significantly improved usability; in particular, its hinged design obviates the need to make extreme wrist excursions.

Adult↗
PubMed2001

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.

Dissection↗
PubMed2000

Hand-assisted laparoscopic surgery: an overview.

BACKGROUND: Advanced laparoscopic surgery is complex and time-consuming. Achieving consistent efficacy and safety throughout the entire procedure is always a problem. For this reason, hand-assisted laparoscopic surgery (HALS) was developed. METHODS: Devices were designed to allow manual access to the abdomen through the utility laparotomy. By using one hand in the abdomen during laparoscopy, the surgeon regains direct tactile sensation and acquires improved hand-eye coordination. The safety of the individual devices has been tested in RCT for the registration of the individual devices. An index known as Surgical Action Efficiency was calculated for in six patients undergoing laparoscopic colon resection and six patients with hand-assisted colon resections. RESULTS: All of the registered devices are safe. Surgical Action Efficiency for the laparoscopy group was 55 +/- 14%; for the HALS group, it was 71 +/- 4%. This result is statistically significant (p < 0.05). CONCLUSION: HALS is a safe and efficient method by which it is possible to combine the established convenience and safety of open surgery with the advantages of minimally invasive surgery.

Hand↗
PubMed2000

Observation in laparoscopic surgery: overview of impeding effects and supporting aids.

Within a Dutch research program on minimally invasive surgery, a large literature survey has been carried out. This article describes the state of the art in research on observation in laparoscopy. It gives an overview of factors impeding the surgeon and technical developments designed to overcome these problems. A large number of journals, proceedings, patents, and books starting from the year 1991 have been consulted. The survey was completed with a thorough MEDLINE search. The survey showed that many authors have an incomplete background in the fundamentals of visual perception. This leads to a lack of understanding and to the design of supporting aids that often are not very useful. The new aspect of this study is that it gives a complete and structured overview of laparoscopic observation problems and current solutions. The observation problems are structured according to visual perception theory. The solutions are critically considered, and their benefits and drawbacks are identified. The study shows that the benefits of stereo-endoscopes and motorized endoscope positioners are questionable. The addition of shadows and movement parallax is still a very important research topic.

Humans↗
PubMed2000

Controlled balloon dilatation for laparoscopic extraperitoneal bladder neck suspension in patients with previous abdominal surgery.

PURPOSE: The balloon dilator is used in a variety of minimally invasive preperitoneal and retroperitoneal operations. In this study, we compared the ability to create an extraperitoneal cavity using a balloon spacer in patients with and without previous abdominal surgery undergoing laparoscopic bladder neck suspension. PATIENTS AND METHODS: This prospective study included 38 patients in total, 15 of whom had had previous abdominal wall surgery and 23 who had not. A balloon spacer technique was used to develop the extraperitoneal space. RESULTS: In 80% of the patients with previous surgery, the introduction of the balloon spacer was recorded as simple; in 20%, it was considered difficult. In 78% of the patients without previous surgery, the introduction of the balloon spacer was recorded as simple, in 17% it was difficult, and in 4% it failed. In 80% of the patients with previous surgery, the extraperitoneal view was good or acceptable, in 20% it was poor, and in 13% it failed. In 92% of the patients without previous surgery, the extraperitoneal view was good or acceptable, in 4% it was poor, and in 4% dilatation failed. Morbidity was equally divided between the groups. CONCLUSIONS: Previous abdominal surgery is not a contraindication to laparoscopic extraperitoneal surgery using a balloon spacer. The approach carries low morbidity, similar to that in patients without previous abdominal surgery.

Abdomen↗
PubMed2000

Comparison of efficiencies of three techniques for colon surgery.

PURPOSE: To determine the most efficient technique for performing a colectomy, we used the methodology of time-motion analysis. METHODS: The efficiency of five hand-assisted and six regular laparoscopic colectomies and one open colectomy, performed by four surgeons in three different hospitals, was measured. The open colectomy was analyzed as a reference procedure. RESULTS AND CONCLUSIONS: The hand-assisted laparoscopic technique was the most efficient. Hand-assisted laparoscopy was therefore less time consuming than laparoscopic surgery. Open surgery was the fastest technique, because the time for every surgical motion is a factor of three shorter than for the two laparoscopic techniques.

Colectomy↗
PubMed1999

Sensitivity of laparoscopic dissectors. What can you feel?

BACKGROUND: Sensory feedback is reduced considerably in minimally invasive procedures by the interposition of instruments, causing loss of direct manual contact with the tissue. The purpose of this study was to evaluate the feedback quality of commercially available reusable and disposable laparoscopic dissectors. METHODS: A total of 31 participants were asked to feel a simulated arterial pulse with their bare fingers and through laparoscopic dissectors, tweezers, an orthopedic forceps, and a laparoscopic low-friction prototype. The absolute sensory threshold was determined by the psychophysical method of limits. RESULTS: The sensory feedback quality was significantly better for the reusable dissectors tested than for the disposable dissector (p < 0.001). Nevertheless, the reusable dissectors were at least eight times less sensitive than bare fingers. Furthermore, sensitivity qualities were highly variable, depending on the dissector tested. CONCLUSIONS: This study showed that the overall sensitivity loss through instruments could be accurately assessed, proving that the sensory feedback for commercially available instruments was low compared to bare fingers. The good sensory feedback results of the prototype indicated that careful design could decrease the overall sensitivity loss.

Adult↗