Biomedical subjects

L P S Stassen

Publications and source records attributed to L P S Stassen.

14 recordsLinked to original sources

PubMed2006

Laparoscopic rectovaginopexy for rectal prolapse.

BACKGROUND: Open rectovaginopexy is an effective procedure for the treatment of both rectal prolapse and anterior rectocele. This study investigates our results of laparoscopic rectovaginopexy (LRVP). METHODS: A consecutive series of 14 patients (median age, 73 years; range 24-92) with rectal prolapse was planned for LRVP. Pre-, per- and postoperative parameters were recorded. Followup was performed at the outpatients' clinic. RESULTS: The median length of hospital stay was 6 days (range, 3-14). There was one fatal cerebrovascular accident 14 days postoperatively; this patient was excluded from further analysis. Median follow-up was 7 months (range, 0.75-38). During follow-up, 11 of 13 patients (85%) experienced resolution or major improvement of their symptoms. Anal incontinence was diminished in 9 of 13 cases (69%). Constipation improved in 2 of 3 patients (66%). These three patients experienced a combination of both anal incontinence and costipation, preoperatively. Recurrence occurred in 2 patients (15%). Two others had a minor residual mucosal prolapse. No patients reported symptoms suggestive of operation-induced constipation or dyspareunia. CONCLUSIONS: LRVP is feasible, and seems to be an effective procedure for rectal prolapse. No operation-induced constipation was observed in this series. Taking into account the age and co-morbidities of these patients, morbidity and mortality may be considered acceptable.

Adult↗

PubMed2006

The influence of different training schedules on the learning of psychomotor skills for endoscopic surgery.

BACKGROUND: Psychomotor skills for endoscopic surgery can be trained with virtual reality simulators. Distributed training is more effective than massed training, but it is unclear whether distributed training over several days is more effective than distributed training within 1 day. This study aimed to determine which of these two options is the most effective for training endoscopic psychomotor skills. METHODS: Students with no endoscopic experience were randomly assigned either to distributed training on 3 consecutive days (group A, n = 10) or distributed training within 1 day (group B, n = 10). For this study the SIMENDO virtual reality simulator for endoscopic skills was used. The training involved 12 repetitions of three different exercises (drop balls, needle manipulation, 30 degree endoscope) in differently distributed training schedules. All the participants performed a posttraining test (posttest) for the trained tasks 7 days after the training. The parameters measured were time, nontarget environment collisions, and instrument path length. RESULTS: There were no significant differences between the groups in the first training session for all the parameters. In the posttest, group A (training over several days) performed 18.7% faster than group B (training on 1 day) (p = 0.013). The collision and path length scores for group A did not differ significantly from the scores for group B. CONCLUSION: The distributed group trained over several days was faster, with the same number of errors and the same instrument path length used. Psychomotor skill training for endoscopic surgery distributed over several days is superior to training on 1 day.

Adult↗

PubMed2006

Problems with technical equipment during laparoscopic surgery. An observational study.

BACKGROUND: This study was designed to investigate the incidence of technical equipment problems during laparoscopic procedures. METHODS: A video-capturing system was used, consisting of an analog video recorder with three camera image inputs and a microphone. Problems with all technical equipment used by the surgical team, such as the insufflator, diathermy apparatus, monitors, light source, camera and camera unit, endoscope, suction devices, and instruments, were registered. RESULTS: In total, 30 procedures were randomly videotaped. In 87% (26/30) of the procedures, one or more incidents with technical equipment (49 incidents) or instruments (9 incidents) occurred. In 22 of those incidents (45%) the technical equipment was not correctly positioned or not present at all; in the other 27 (55%), the equipment malfunctioned as a result of a faulty connection (9), a defect (5), or the wrong setting of the equipment (3). In 10 (20%) cases the exact cause of equipment malfunctioning was unclear. CONCLUSIONS: The incidence of problems with laparoscopic technical equipment is high. To prevent such problems, improvement and standardization of equipment is needed, combined with the incorporation of checklist use before the start of a surgical procedure. Future research should be aimed at development, implementation, and evaluation of these measures into the operating room.

Adult↗

PubMed2006

[Guideline 'Diagnosis and treatment of oesophageal carcinoma'].

An evidence-based guideline for the diagnosis and treatment of oesophageal carcinoma was developed on the initiative of the Netherlands Society of Gastroenterohepatology in cooperation with the Dutch Institute for Healthcare Improvement (CBO) and the Dutch Association of Comprehensive Cancer Centres. If a patient with oesophageal carcinoma is eligible for treatment with curative intent, they should undergo thoracic and abdominal CT, ultrasound investigation of the supraclavicular region and endoscopic ultrasonography for staging purposes. Endoscopic therapy is the preferred treatment for high-grade dysplasia or early cancer in Barrett's oesophagus confined to the mucosa. Surgical resection is indicated if the tumour invades the submucosa. If resection of the oesophageal carcinoma is performed with curative intent, one should aim for radical resection. The type and extent of the resection depends on the location of the tumour. There is evidence that the mortality rate following surgery can be reduced by performing it in centres with ample experience with oesophageal cancer surgery. Preoperative chemotherapy and radiotherapy may improve survival in patients with oesophageal carcinoma. Palliative treatment for oesophageal carcinoma should be considered in cases of local invasion of surrounding organs, metastases, poor physical condition of the patient or recurrent disease after previous curative treatment. Psychosocial support is an important element in the follow-up of patients with oesophageal carcinoma.

Antineoplastic Agents↗

PubMed2006

Validation of a new basic virtual reality simulator for training of basic endoscopic skills: the SIMENDO.

BACKGROUND: The aim of this study was to establish content, face, concurrent, and the first step of construct validity of a new simulator, the SIMENDO, in order to determine its usefulness for training basic endoscopic skills. METHODS: The validation started with an explanation of the goals, content, and features of the simulator (content validity). Then, participants from eight different medical centers consisting of experts (> or =100 laparoscopic procedures performed) and surgical trainees (<100) were informed of the goals and received a "hands-on tour" of the virtual reality (VR) trainer. Subsequently, they were asked to answer 28 structured questions about the simulator (face validity). Ratings were scored on a scale from 1 (very bad/useless) to 5 (excellent/very useful). Additional comments could be given as well. Furthermore, two experiments were conducted. In experiment 1, aimed at establishing concurrent validity, the training effect of a single-handed hand-eye coordination task in the simulator was compared with a similar task in a conventional box trainer and with the performance of a control group that received no training. In experiment 2 (first step of construct validity), the total score of task time, collisions, and path length of three consecutive runs in the simulator was compared between experts (>100 endoscopic procedures) and novices (no experience). RESULTS: A total of 75 participants (36 expert surgeons and 39 surgical trainees) filled out the questionnaire. Usefulness of tasks, features, and movement realism were scored between a mean value of 3.3 for depth perception and 4.3 for appreciation of training with the instrument. There were no significant differences between the mean values of the scores given by the experts and surgical trainees. In response to statements, 81% considered this VR trainer generally useful for training endoscopic techniques to residents, and 83% agreed that the simulator was useful to train hand-eye coordination. In experiment 1, the training effect for the single-handed task showed no significant difference between the conventional trainer and the VR simulator (concurrent validity). In experiment 2, experts scored significantly better than novices on all parameters used (construct validity). CONCLUSION: Content, face, and concurrent validity of the SIMENDO is established. The simulator is considered useful for training eye-hand coordination for endoscopic surgery. The evaluated task could discriminate between the skills of experienced surgeons and novices, giving the first indication of construct validity.

Adult↗

PubMed2005

[Abscess formation due to lost stones during laparoscopic cholecystectomy].

Two women aged 79 and 69 years presented with abdominal pain at 15 and 38 months respectively after a laparoscopic cholecystectomy. In both cases perforation of the gallbladder had occurred with spillage of bile and gallstones. A CT-scan carried out at presentation showed signs of an abdominal abscess. The origin of the abscess was initially unknown. The first patient was operated on immediately. In the second patient a drain was placed in the abscess under ultrasound guidance. During operation gallstones were seen in the abscess cavity in both patients. Both patients recovered well. Although perforation of the gallbladder with spillage of gallstones during laparoscopic cholecystectomy often occurs, the incidence of major postoperative complications is low. However, in some cases reoperation is necessary. Removal of all spilled stones is therefore indicated to prevent complications. If abdominal symptoms persist after laparoscopic cholecystectomy, an abscess due to spilled gallstones should be considered. Ultra-sound or CT are the most sensitive means of for tracing spilled gallstones or abscesses.

Abdominal Abscess↗

PubMed2005

Fundamental aspects of learning minimally invasive surgical skills.

With the introduction of minimally invasive surgery (MIS) the necessity to develop training methods to learn skills outside the operating room (OR) became clear. Several training simulators have become commercially available. However, fundamental research into the requirements for effective and efficient training in MIS is still lacking. Yet in the literature several learning models have been described that may be used when designing the structure of a training program. While learning skills, three stages can be observed: cognitive, associative and autonomous. The learning cycle also includes different learning styles and, moreover, every trainee has his/her preferred learning style. Furthermore, training should be adapted to the level of behaviour: skill-based, rule-based or knowledge-based. Training of complex skills should include multiple performance objectives, such as just-in-time supportive information and part-task practice. Finally, motivation for training can be created by assessment. In conclusion, several theories on learning can be found in the literature. These theories may help in the development of effective training programs for training MIS skills outside the OR.

Journal Article↗

PubMed2003

Prolonged abdominal wall pain caused by transfascial sutures used in the laparoscopic repair of incisional hernia.

The use of transfascial sutures in the laparoscopic repair of incisional hernia has considerably facilitated the accurate intraperitoneal placement and fixation of the synthetic mesh. The laparoscopic procedure has a number of advantages, including less morbidity and pain. Moreover, the use of a mesh prosthesis results in a low rate of hernia recurrence. Despite the benefits associated with this technique, several (minor) complications have been documented. Herein we describe a case of prolonged abdominal wall pain after laparoscopic hernia mesh repair that was caused by the use of transfascial sutures.

Abdominal Pain↗

PubMed2003

Rasmussen's model of human behavior in laparoscopy training.

AIMS: Compared to aviation, where virtual reality (VR) training has been standardized and simulators have proven their benefits, the objectives, needs, and means of VR training in minimally invasive surgery (MIS) still have to be established. The aim of the study presented is to introduce Rasmussen's model of human behavior as a practical framework for the definition of the training objectives, needs, and means in MIS. METHODS: Rasmussen distinguishes three levels of human behavior: skill-, rule-, and knowledge-based behaviour. The training needs of a laparoscopic novice can be determined by identifying the specific skill-, rule-, and knowledge-based behavior that is required for performing safe laparoscopy. Future objectives of VR laparoscopy trainers should address all three levels of behavior. RESULTS: Although most commercially available simulators for laparoscopy aim at training skill-based behavior, especially the training of knowledge-based behavior during complications in surgery will improve safety levels. However, the cost and complexity of a training means increases when the training objectives proceed from the training of skill-based behavior to the training of complex knowledge-based behavior. CONCLUSION: In aviation, human behavior models have been used successfully to integrate the training of skill-, rule-, and knowledge-based behavior in a full flight simulator. Understanding surgeon behavior is one of the first steps towards a future full-scale laparoscopy simulator.

Algorithms↗

PubMed2002

A clearly visible endoscopic instrument shaft on the monitor facilitates hand-eye coordination.

BACKGROUND: Passing an instrument through a small incision alters the kinematics of the instrument, thus hampering hand-eye coordination. Nevertheless, the incision provides a stable, nearly invariant, point of rotation for instrument movements. Therefore, we set out to evaluate the effects of the altered kinematics on hand-eye coordination. In addition, we assessed the hypothesis that the hand-eye coordination of laparoscopic surgeons incorporates the incision as a point of reference. METHODS: Eight surgeons with experience in laparoscopy repeatedly performed a positioning task on a two-dimensional endoscopic manipulation simulator. Task time was measured. In the first experiment, normal endoscopic manipulation was compared to a condition in which the kinematic effects of the incision were compensated for. In the second experiment, the instrument shaft on the monitor was not visible during half of the trials, so that all visual information about the location of the incision was obscured. RESULTS: Task performance improved significantly when the kinematic effects of the incision were compensated for (p = 0.001). Task performance improved when the instrument shaft was clearly visible on the monitor (p <0.05). CONCLUSIONS: Compensating for the kinematic effects introduced by the incision improves hand-eye coordination. The results of this study indicate that the incision provides a point of reference for hand-eye coordination during endoscopic manipulation.

Computer Simulation↗

PubMed2002

Transanal endoscopic microsurgery for rectal cancer.

If curation is intended for rectal cancer, total mesorectal excision with autonomic nerve preservation (TME) is the gold standard. Transanal resection is tempting because of low mortality and morbidity rates. However, inferior tumour control, provoked by the limitations of the technique, resulted in its cautious application and use mainly for palliation. Transanal endoscopic microsurgery (TEM) is a minimal invasive technique for the local resection of rectal tumours. It is a one-port system, introduced transanally. An optical system with a 3D-view, 6-fold magnification and resolution as the human eye, together with the creation of a stabile pneumorectum, and specially designed instruments allow full-thickness excision under excellent view and a proper histological examination. The technique can also be applied for larger and more proximal tumours. Mortality, morbidity as well as incomplete excision rates are minimal. Local recurrence and survival rates seem comparable to TME in early rectal cancer. TEM is the method of choice when local resection of rectal cancer is indicated. Results justify a re-evaluation of the indications for the local excision of rectal cancer with a curative intent.

Adult↗

PubMed2002

Hospital volume and post-operative mortality after resection for gastric cancer.

AIMS: In low-volume hospitals, expertise in gastric surgery is difficult to maintain because of the decreasing incidence of gastric cancer and the fall of surgery for ulcer disease. We evaluated the prognostic impact of hospital volume on post-operative mortality (POM) in a consecutive series of 1978 patients. METHODS: Information on patients undergoing resection for gastric cancer in the period 1987-97 was retrieved from the Rotterdam Cancer Registry. The relationship between hospital volume and POM was analysed by logistic regression, adjusting for other prognostic factors. RESULTS: POM was 7.9% on average but varied between the 22 hospitals from 3.1% to 15.1% (P=0.15). Hospital volume had no prognostic influence (P=0.74). Prognostic factors were age (70-79 years odds ratio (OR)=3.8, 80+ years OR=6.0), sex (male OR=1.7), stage (IV OR=1.8) and (partial) gastrectomy for cardia cancers (OR=2.0). CONCLUSION: Variation in POM between hospitals was large but not related to hospital volume. For cardia cancer, POM rates were lower after oesophagogastrectomy.

Adult↗

PubMed2002

The perspective effect of wide-angle lenses in laparoscopes.

PURPOSE: To evaluate the effect of perspective distortion of wide-angle lenses in laparoscopes on hand-eye coordination during endoscopic manipulation. METHODS: Sixteen subjects repeatedly performed a standardized positioning task in a pelvi-trainer under two conditions. The subjects had no prior experience with endoscopic manipulation. In one condition, a wide-angle lens with considerable perspective distortion was used; in the other, a telephoto lens without perspective distortion was used. Task time and number of errors were measured. RESULTS: Task time and the number of errors did not significantly increase in the condition with a wide-angle lens. CONCLUSIONS: The perspective effect did not influence task performance in endoscopic manipulation in this experiment. Subjects indicated that they even preferred the wide-angle lens because its extreme perspective improved their perception of depth.

Adult↗

PubMed2001

Time-action analysis of instrument positioners in laparoscopic cholecystectomy.

BACKGROUND: Instrument positioners can position and lock a laparoscopic instrument. This study uses time-action analysis to evaluate objectively whether IPs can substitute for a surgical assistant efficiently and safely. METHODS: In four hospitals, 78 laparoscopic cholecystectomies were randomly assisted by a surgical assistant or an instrument positioner (AESOP and PASSIST) The efficiency and safety of laparoscopic cholecystectomies were analyzed with respect to time, number and type of actions, positioning accuracy, and peroperative complications. A questionnaire evaluated the difficulties for each operation and the comfort of instrument positioner use. RESULTS: The PASSIST and AESOP were able to replace the surgical assistant during laparoscopic cholecystectomies without significantly changing either the efficiency or the safety of the operation. The questionnaire showed that the surgeons preferred to operate with an instrument positioner. CONCLUSION: This study assessed objectively that instrument positioners can substitute for a surgical assistant efficiently and safely in elective laparoscopic cholecystectomies.

Cholecystectomy, Laparoscopic↗