Sequence and task analysis of instrument use in common laparoscopic procedures.

BACKGROUND: In the area of instrument evaluation, one aspect that still requires objective assessment is the dynamics of instrument maneuver and exchange. If we could gain a better understanding of these phenomena, we could improve the design of the instruments themselves. METHODS: A total of 29 laparoscopic procedures were videotaped and reviewed using time motion analysis. Instrument multifunctionality was determined using a standardized list of laparoscopic maneuvers. State transition diagrams were utilized to document the sequence of instrument exchanges. RESULTS: The curved dissector, atraumatic grasper, and cautery scissors were identified as the most multifunctional instruments; each was able to perform five distinct maneuvers. Instrument sequences were found to consist of a three-part dissect --> clip --> cut cycle and a two-part dissect --> suction cycle of instrument exchange. CONCLUSION: This study demonstrated that laparoscopic instruments are often used to perform a variety of maneuvers in addition to their primary function. Furthermore, there are common patterns in instrument exchange that provide a potential source of design parameters for improved surgical efficiency.

Design of multifunctional compliant mechanisms for minimally invasive surgery.

Compliant mechanisms that can perform multiple unique functions have great potential for use in minimally invasive therapy. A fully compliant mechanism may be thought of as a monolithic mechanism without hinge joints which uses elastic deformation to achieve force and motion transmission. Incorporating multifunctional compliant mechanisms into minimally invasive surgical tools has many possible advantages, including reduced instrument exchanges and additional dexterity at the surgical site. Compliant mechanisms also offer the advantage of single-piece construction and ease of manufacture over their rigid-link counterparts, eliminating the need for complex millimeter-scale assembly and cleaning in hinge areas. A multicriteria topology optimization procedure for the design of multifunctional compliant mechanisms is illustrated through the design of a combination tool that will perform forceps and scissor function. A working solid model of the combination forceps/scissors has been generated based on the optimal topology. Results of detailed finite element modeling are discussed along with implications for practical manufacture and implementation.

Postgraduate year does not influence operating time in laparoscopic cholecystectomy.

BACKGROUND: Surgical resident education may contribute to increased operating time, thus increasing costs at teaching institutions. It is possible that junior residents, in particular, with less experience could contribute to longer operating times for laparoscopic cholecystectomy. We hypothesized that all general surgery residents, regardless of level of training and with proper supervision, could complete a laparoscopic cholecystectomy in a safe and timely fashion. MATERIALS AND METHODS: A retrospective study was performed using data collected from laparoscopic cholecystectomies completed under the supervision of one attending surgeon over a 2-year period. Operating times were recorded, the operating surgeon was identified, and cases were assigned an acuity level based on pathologic findings. Operative times were compared after dividing surgeons into three groups (junior residents, senior residents, and staff). RESULTS: Seventy-one cases were entered into the study. There were no differences when comparing mean operating times among the three groups (P = 0.2, analysis of variance). The pathologic acuity in each group was similar (P = 0.8, Fisher's exact test). There was a difference when evaluating the operating times for the pathologic level of acuity (P = 0.002, Kruskal-Wallis test). CONCLUSIONS: Resident level does not affect the operating time in performing laparoscopic cholecystectomy. The pathologic acuity of the gallbladders was distributed similarly for all three groups. There was a difference in mean operating time based on pathologic acuity. Laparoscopic cholecystectomy can be performed in a safe and efficient manner at a teaching institution.

Video microsurgery: evaluation of standard laparoscopic equipment for the practice of microsurgery.

Traditional microsurgery involves the use of bulky and expensive stereo microscopes that have limited portability. Recent advances in video technology have enabled the exploration of alternative visualization methods. The purpose of this study was to evaluate standard laparoscopic equipment for microvascular anastomoses. Eight surgeons completed anastomoses on rat femoral and synthetic vessels using stereo microsurgery and video microsurgery visualization systems. All surgeons had previous experience with stereo microsurgery and none had ever used video microsurgery. Data were collected on overall anastomosis and individual suture times. A sample of completed anastomoses was placed in a video database and evaluated by use of a quality rating scale (8 to 10, excellent; 6 to 7, adequate; less than 6, poor). All surgeons subjectively evaluated the video microsurgery system. A total of 48 anastomoses were completed. The average total anastomosis time for the stereo microsurgery was 1018.9 +/- 463.2 seconds versus 1738.9 +/- 460.1 seconds for the video microsurgery. The average individual suture placement time was 114.6 +/- 60.6 seconds for the stereo microsurgery versus 211.7 +/- 128.4 seconds for the video microsurgery (p < 0.05). Twenty-five of the anastomoses underwent quality review. The overall score of the stereo microsurgery group was 8.1 +/- 1.7, and the video microsurgery group had an overall score of 7.3 +/- 1.6. Survey results revealed that 75 percent of the participants thought that the video microsurgery would be useful for human operations and would improve surgeon comfort, but 87.5 percent would not use the present video microsurgery system over stereo microsurgery in their practice. Although significant differences exist in overall anastomosis and individual suture completion times, no difference was found in the overall quality. Video microsurgery could become a useful tool on the basis of surgeon ergonomics; however, optical parameters require further refinement.

Use of a human patient simulator in the development of resident trauma management skills.

BACKGROUND: Computerized human patient simulators (HPSs) have been used to improve diagnostic and therapeutic decision making. The goal of this study was to investigate the impact of HPSs and Advanced Trauma Life Support (ATLS) on the development of trauma management skills and self-confidence in surgical interns. METHODS: Three teams of interns completed two ATLS-like trauma scenarios on the HPS (pre-ATLS). They then took the ATLS provider course. After ATLS, the interns were evaluated on two different HPS trauma scenarios (post-ATLS). Two teams of senior residents, experienced in trauma care, completed the same HPS scenarios and were used as controls. Trauma management skills were scored in three areas--critical treatment decisions, potential for adverse outcomes, and team behavior--by staff trauma surgeons. After participating in the HPS trauma scenarios, the interns completed self-confidence questionnaires and a course evaluation survey. RESULTS: Trauma management skill scores increased 23% in critical treatment decisions, 25% in potential for adverse outcomes, and 47% in team behavior after ATLS/HPS (p < 0.002). Senior residents' performance on HPS trauma scenarios was better than the interns (p < 0.05) in all three areas evaluated. The interns' self-confidence scores rose significantly after the course. (p < 0.01) The HPS course evaluation survey averaged 8.3 out of a maximum 10. CONCLUSION: Use of HPSs in conjunction with ATLS appears to enhance the development of trauma management skills. The surgical interns participating in the study deemed the HPS to be a worthwhile experience and a confidence-building tool. In particular, trauma team behavior improved significantly after ATLS/HPS.

A virtual reality surgical trainer for navigation in laparoscopic surgery.

A virtual reality trainer was designed to familiarize students and surgeons with surgical navigation using an angled laparoscopic lens and camera system. Previous laparoscopic trainers have been devoted to task or procedure training. Our system is exclusively devoted to laparoscope manipulation and navigation. Laparoscopic experts scored better than novices in this system suggesting construct validity. The trainer received favorable subjective ratings. This simulator may provide for improved navigation in the operating room and become a useful tool for residents and practicing surgeons.

A prototype haptic suturing simulator.

A new haptic simulation designed to teach basic suturing for simple wound closure is described. Needle holders are attached to the haptic device as the graphics of the needle holders, needle, sutures and virtual skin are displayed and updated in real time. The simulator incorporates several interesting components such as real-time modeling of deformable skin, tissue and suture material and real-time recording of state of activity during the task using a finite state model.

Pseudoachalasia as a result of metastatic cervical cancer.

BACKGROUND: Distinguishing achalasia from pseudoachalasia can be difficult, as the clinical, radiological, and manometric findings can be similar to those seen in achalasia. The features that may differentiate achalasia from pseudoachalasia are reviewed and the pathogenesis of pseudoachalasia is discussed. METHODS: A patient presented with a clinical scenario of achalasia that was documented by radiographic, endoscopic, and manometric studies. Her past medical history was significant for cervical cancer. Although brief improvement in symptoms was achieved with botulinum toxin injections and esophageal dilation, she had continued progression of symptoms. This direct involvement of the esophagus by a tumor was not demonstrated by any of the routine preoperative studies. RESULTS: At the time of surgery, extensive involvement of the diaphragm, esophagus, and pericardium by a tumor was noted. Pathologic analysis of the tumor was consistent with metastatic cervical cancer CONCLUSION: Pseudoachalasia has been known to occur in response to both benign and malignant causes. Differentiating between pseudoachalasia and achalasia is often difficult because of the similarities. As in this case, the diagnosis of pseudoachalasia may be made by surgical exploration.

Are surgery training programs ready for virtual reality? A survey of program directors in general surgery.

BACKGROUND: The use of advanced technology, such as virtual environments and computer-based simulators (VR/CBS), in training has been well established by both industry and the military. In contrast the medical profession, including surgery, has been slow to incorporate such technology in its training. In an attempt to identify factors limiting the regular incorporation of this technology into surgical training programs, a survey was developed and distributed to all general surgery program directors in the United States. STUDY DESIGN: A 22-question survey was sent to 254 general surgery program directors. The survey was designed to reflect attitudes of the program directors regarding the use of computer-based simulation in surgical training. Questions were scaled from 1 to 5 with 1 = strongly disagree and 5 = strongly agree. RESULTS: A total of 139 responses (55%) were returned. The majority of respondents (58%) had seen VR/CBS, but only 19% had "hands-on" experience with these systems. Respondents strongly agreed that there is a need for learning opportunities outside of the operating room and a role for VR/CBS in surgical training. Respondents believed both staff and residents would support this type of training. Concerns included VR/CBS' lack of validation and potential requirements for frequent system upgrades. CONCLUSIONS: Virtual environments and computer-based simulators, although well established training tools in other fields, have not been widely incorporated into surgical education. Our results suggest that program directors believe this type of technology would be beneficial in surgical education, but they lack adequate information regarding VR/CBS. Developers of this technology may need to focus on educating potential users and addressing their concerns.

Laparoscopic-assisted renal biopsy: an alternative to open approach.

An open renal biopsy frequently is performed when the conventional percutaneous approach is contraindicated. Although many of the surgical procedures, previously performed by a traditional open technique, are now successfully accomplished by laparoscopic technique, there remains a paucity of reports on laparoscopic kidney biopsy. We describe the use of laparoscopic technique in performing native kidney biopsy in three patients and review the potential safety and accuracy of this approach. To date, laparoscopic-assisted renal biopsy has been reported in six patients. The average length of stay in our small series was 1.3 days, and there were no major or catastrophic complications. Adequate numbers of glomeruli for confirmation of microscopic diagnosis were obtained in all cases. The review of literature, in addition to our encouraging preliminary results of a small group of patients, shows a possible role of laparoscopic-assisted renal biopsy in place of an open renal biopsy.

Computers and virtual reality for surgical education in the 21st century.

Surgeons must learn to perform operations. The current system of surgical resident education is facing many challenges in terms of time efficiency, costs, and patient safety. In addition, as new types of operations are developed rapidly, practicing surgeons may find a need for more efficient methods of surgical skill education. An in-depth examination of the current learning environment and the literature of motor skills learning provides insights into ways in which surgical skills education can be improved. Computers will certainly be a part of this process. Computer-based training in technical skills has the potential to solve many of the educational, economic, ethical, and patient safety issues related to learning to perform operations. Although full virtual-reality systems are still in development, there has been early progress that should encourage surgeons to incorporate computer simulation into the surgical curriculum.

Practical training for postgraduate year 1 surgery residents.

BACKGROUND: Surgical interns accept significant patient care responsibilities with minimal orientation. We have developed a multifaceted training program for incoming surgical interns in which learning in a simulated environment plays a key role. The purpose of this study was to evaluate resident perceptions of simulated clinical calls as an educational modality and to measure the effect on self-ratings of confidence. METHODS: A multidisciplinary team compiled 15 clinical scenarios. Simulated nurse-to-resident clinical call sessions were held on 3 separate days. Daily course evaluation surveys and identical precourse and postcourse confidence surveys were completed. RESULTS: The resident confidence measure increased significantly postcourse (6.73 versus 8.35, P <0.03). The evaluation survey score averaged 4.35 out of 5. CONCLUSIONS: Simulated clinical call sessions were well received and resulted in a significant increase in resident confidence levels. Based on this modality's apparent efficacy and ease of implementation, we offer it as a useful educational tool for incoming postgraduate year-1 surgical residents.

Tactile feedback is present during minimally invasive surgery.

BACKGROUND: The applications of minimally invasive surgery (MIS) and laparoscopy are rapidly expanding. Despite this expansion, our understanding of the importance of haptic feedback during laparoscopic surgery is incomplete. Although many surgeons believe that the use of minimally invasive techniques eliminates force feedback and tactile sensation (haptics), the importance of haptics in MIS has not been fully evaluated. There is considerable interest in the development of simulators for MIS even though the importance of force feedback remains poorly understood. This study was designed to determine the ability of experienced surgeons to interpret haptic feedback with respect to texture, shape, and consistency of an object. STUDY DESIGN: A randomized, single-blinded study was designed. Twenty surgeons were presented objects in a random order, with participants blinded as to their identity. Inspection by direct palpation, conventional instruments, and laparoscopic instruments was performed on all objects. Statistic analysis of the data was performed using chi-square analysis and, when appropriate, a Fischer exact probability test. RESULTS: Direct palpation was associated with the highest accuracy for shape identification and was superior to both conventional instruments (p < 0.001) and laparoscopic instruments (p<0.001). Fine texture analysis with either a conventional instrument or a laparoscopic instrument was superior to direct palpation (p < 0.05). Finally, the three methods of analysis were comparable for consistency analysis. CONCLUSIONS: These data indicate that laparoscopic instruments do, in fact, provide surgeons with haptic feedback. Interpretation of the texture, shape, and consistency of objects can be performed. In some situations, laparoscopic instruments appear to amplify the haptic information available. Our ongoing work is directed at further defining force interactions.

Defining the role of haptic feedback in minimally invasive surgery.

INTRODUCTION: The applications of Minimally Invasive Surgery (MIS) and Laparoscopy are rapidly expanding. Despite this expansion, the technology related to our understanding of the importance of haptic feedback related to laparoscopic surgery remains in its infancy. While many surgeons feel that the use of minimally invasive techniques eliminates force feedback and tactile sensation, the importance of haptics in MIS has not been fully evaluated. Moreover, there is considerable interest in the development of haptic simulators for MIS even though the importance of force feedback remains poorly understood. This study was designed to determine the ability of novice surgeons to interpret haptic feedback with respect to texture, shape and consistency of an object. METHOD: Subjects were presented objects in a random order and participants were blinded as to their identity. Inspection by direct palpation, palpation with conventional instruments, and palpation with laparoscopic instruments was performed on all objects. Statistical analysis of the data was performed using a Fischer exact probability test. RESULTS: Direct palpation provided the greatest degree of haptic feedback and was associated with the highest accuracy for texture discrimination, shape discrimination, and consistency discrimination. A significant decrease in the ability to identify shapes was noted with both CI and LI. A significant decrease in the ability to differentiate consistency was noted for LI only. When comparing palpation with conventional instruments to palpation with laparoscopic instruments, there was no significant difference in shape or texture discrimination. There was, however, a significant decrease in consistency discrimination. CONCLUSION: This data indicates that laparoscopic instruments do in fact provide the surgeon with haptic feedback. While the instruments change the information available to the surgeon, interpretation of the texture, shape and consistency of objects can be performed. Our ongoing work is directed at further defining force interactions. Through the use of force feedback impulse devices in VR simulators, one should be able to create a more realistic theatre in which the novice surgeon can learn operative skills that will readily translate into the operating room.

A comparison of gradual distraction techniques for modification of the midface in growing sheep.

The authors carried out experiments to advance the midface in growing sheep using a distraction force across the zygomaticomaxillary sutures. They wished to assess the possibility of performing distraction osteogenesis across intact sutures as well as distraction after Le Fort osteotomies. Their results demonstrate that the technique of gradual distraction after osteotomy is successful in the growing animal. Bilateral distraction across intact sutures did not advance the midface or change the dental relationship. Unilateral distraction was successful in angulating the midface away from the distracting force in the intact growing animal. Alternating unilateral distraction or "waltzing" was surprisingly effective in advancing the midface in one of the animals studied and may become applicable in some craniofacial deformities. In all intact animals there was some expansion of the zygomaticomaxillary suture as well as a substantial migration of the distraction devices through the bone.

Simulation and virtual reality for surgical education.

Rapid advancements in technology have dramatically changed the way our daily activities are conducted. In the practice of medicine and surgery, technological advances over the past few decades have had an enormous impact on the diagnosis and treatment of disease. In contrast, our methods of teaching surgeons to perform operations remain mired in the 100 year old Halstedian apprenticeship model. In this system, surgeons often learn to operate based on the principle of "see one, do one, teach one." Educational opportunities are largely dependent on chance as a patient with a particular disease pattern must present to the surgeon in order to achieve specific educational goals. Live patients are often used as the initial "practice session" for the learning surgeon in this model of education.