Experimental trial of transvaginal cholecystectomy: an ex vivo analysis of the learning process for a novel single-port technique.

BACKGROUND: Interest in natural orifice transluminal endoscopic surgery (NOTES) has expanded, and the first experiences with patients using different techniques have been reported. However, no work has addressed the learning process or the limitations of the procedures. The relation between inexperience and complications became a major concern after the introduction of laparoscopic surgery. This study investigates the learning process for a new technique using specially designed instruments in an ex vivo model before clinical application. METHODS: Specially designed instruments and a single-port technique using the Tuebingen Trainer were used to evaluate instrument and surgeon performance (learning curve) in terms of time and errors. A total of 90 procedures performed by three surgeons were evaluated. Group and individual learning curves were plotted. RESULTS: All the surgeons showed a reduction in both mean cholecystectomy time (subject A: 27.2 vs 16.6 min; subject B: 21.4 vs 19.22 min; subject C: 21 vs 19.7 min) and mean errors (subject A: 2.8 vs 1.6; subject B: 3.5 vs 2.6; subject C: 3.5 vs 2). A plateau was reached after approximately 15 procedures. Group learning curve analysis showed a significant reduction in time between the first group (mean, 24.97 +/- 5.8 min) and last group (mean, 19.30 +/- 3.09 min; F[1,28] = 11.83; p = 0.001) for 15 procedures, as well as reduced technical errors in the fifth group, from 3.7 +/- 1.65 to 1.6 +/- 1.04 (F[1,28] = 8.90; p < 0.01), demonstrating a learning effect. The number of optic and access port position changes were recorded, setting a standard for normal instrument performance. CONCLUSION: This study shows that the tasks of cholecystectomy can be learned safely in a reasonable number of simulations with the new instruments. Although this is a new technique, prior laparoscopic surgery experience is helpful. The technique offers an advantage over those using flexible endoscopes.

Laparoscopic intracorporal colorectal sutured anastomosis using the Radius Surgical System in a phantom model.

BACKGROUND: The Radius Surgical System (RSS) is a manipulator with additional degrees of freedom to enhance the dexterity of laparoscopic suturing. Our aim was to determine the feasibility and potentially added value of laparoscopic intracorporal sutured colorectal anastomosis (RSS) compared with suturing with conventional laparoscopic instruments (CLI). METHODS: A total of 72 colorectal anastomoses and 30 single sutures using RSS and CLI were performed in the study. The experiment was divided as follows: One surgeon performed 40 colorectal anastomoses using RSS to assess the learning curve and the feasibility of the technique; The same surgeon performed 10 additional colorectal anastomoses with CLI which were then compared to the last 10 cases of the 40 anastomoses with RSS; Fifteen single sutures in the horizontal plane with RSS and 15 with CLI between two segments of colon were performed to compare the traction force to disrupt the suture; Twelve anastomoses were performed by the other three participants to evaluate ergonomy. RESULTS: Three leakages (7.5%) were found in the 40 anastomoses with RSS but none after the eighth case. There was no stenosis. The mean time for the anastomoses once the learning curve was achieved was 32.7 min. After 21 anastomoses with RSS there was no improvement in the operating time. The quality of the suture was superior with RSS, with a larger anastomosis diameter, higher bursting pressure, and fewer suturing failures being found. The RSS suture withstood a higher traction force. The participants showed more discomfort suturing with CLI. CONCLUSION: This study demonstrated the feasibility of laparoscopic colorectal anastomosis using RSS. Anastomosis with RSS was shown to be safer. The three participants evaluating ergonomy reflected less discomfort in hand/wrist using RSS. Others ergonomic problems were comparable to CLI.

[Natural orifices transluminal endoscopic surgery (NOTES) in Germany: summary of the working group reports of the "D-NOTES meeting 2009"]. / Endoskopisches Operieren über natürliche Körperöffnungen (NOTES) in Deutschland: Zusammenfassung der Arbeitsgruppensitzungen der "D-NOTES 2009"

The D-NOTES-group met in June 2009 for an evaluation of ongoing preclinical and clinical activities in natural orifice endoscopic surgery and the further coordination of research in Germany. Different working groups with various topics were formed. Consensus statements among various participants with different scientific and medical background were initiated. In summary, important topics were handled such as the correct handling of bacterial contamination and related complications, the question of the ideal entry point and a secure closure, interdisciplinary cooperation, and matters related to training and education. Furthermore, participants agreed on terminological basics. A to-do-list for medical engineering was formulated.

Experimental results of mesh fixation by a manual manipulator in a laparoscopic inguinal hernia repair model.

BACKGROUND: Laparoscopic mesh fixation using a stapler can lead to complications such as nerve injury and bowel injury. However, mesh fixation by suturing with conventional laparoscopic instruments (CLI) is difficult because of limited degrees of freedom. A manual manipulator--Radius Surgical System (Radius)--whose tip can deflect and rotate, gives the surgeon two additional degrees of freedom. The aim of this study is to evaluate the introduction of Radius to mesh fixation in laparoscopic inguinal hernia repair. METHODS: A model for inguinal hernia repair was prepared using animal organs in a trainer. Mesh fixation was performed using Radius, stapler, and CLI. Tensile strength during extraction of mesh toward the vertical direction, and execution time, were measured. RESULTS: The mean number of fixation points of Radius, stapler, and CLI was 9.3 +/- 1.5, 8.5 +/- 1.4, and 9.0 +/- 1.0, respectively. The mean tensile strength of fixation of mesh of Radius, stapler, and CLI was 140.7 +/- 48.9, 73.1 +/- 23.4, and 53.6 +/- 31.5 (N), respectively. The mean tensile strength per one fixation point by Radius, stapler, and CLI was 16.5 +/- 5.3, 8.7 +/- 2.8, and 6.3 +/- 3.6 (N), respectively. The mean execution time of Radius, stapler, and CLI was 479 +/- 108, 54 +/- 31, and 431 +/- 77 (sec), respectively. CONCLUSIONS: The mesh fixation by Radius was stronger than that by staples and CLI. Two additional degrees of freedom were useful in difficult angles. The introduction of Radius is feasible and facilitates the fixation of mesh with sutures in laparoscopic inguinal hernia repair.

Precision in stitches: Radius Surgical System.

BACKGROUND: The Radius Surgical System is a manual manipulator with two additional degrees of freedom compared with conventional laparoscopic instruments (CLIs). This study aimed to compare the performance of laparoscopic suturing tasks with the use of the Radius Surgical System and CLIs, respectively. METHODS: Five experienced laparoscopic surgeons performed laparoscopic surgical tasks in a training box. The tasks consisted of knot-tying, suturing, and needle control tasks. The needle control task was performed to evaluate the precision of the needle drive by analysis of the needle exit point on a suture pad. In the knot-tying and suturing tasks, required time and accuracy value were measured. Needle control tasks were performed on three different angulations of plane. The angles between the instrument plane and the target plane (AIT) were 30 degrees, 60 degrees, and 90 degrees. The distance of the exit point to the center of the target field, the number of actions needed to fulfill a single task, and the required time were recorded and analyzed. RESULTS: In the knot-tying and frontal suturing tasks, there were no significant differences between the two groups. In the sagittal suturing task, the required time in the Radius group was significantly shorter than in the CLI group. In the needle control tasks on 30 degree and 60 degree AIT, the distance was significantly shorter in the Radius group than in the CLI group. There were no significant differences in the number of actions or the required time. In the frontal and sagittal needle control task on 90 degree AIT, the distance was significantly shorter in the Radius group than in the CLI group. The number of actions and the required time were significantly less in the Radius group than in the CLI group. CONCLUSIONS: The two additional degrees of freedom contributed to accurate and controlled needle guidance, especially in difficult spatial situations.

Ergonomics with the use of curved versus straight laparoscopic graspers during rectosigmoid resection: results of a multiprofile comparative study.

BACKGROUND: A detailed ergonomic comparison of motions and muscular activity in the left upper extremity using a laparoscopic straight or curved grasper in rectosigmoid resection is presented. METHODS: The study had two parts: experimental and clinical. In the experiment part, 30 laparoscopic sigmoid resections were performed under animal organ phantom conditions. The operations were divided into three groups according to instrument and trocar position. Group 1 (n = 10) underwent operations performed with a curved grasper in the excentral trocar position (in relation to the telescope trocar), with the left-hand curved grasper placed in the right flank and the right hand instrument in the right lower quadrant. In group 2 (n = 10), straight forceps were used in the excentral trocar position. Group 3 (n = 10) underwent laparoscopic sigmoid resection performed with a straight grasper in the central position (in relation to the telescope trocar), with the instruments placed at both sides of the lower abdomen. To measure ergonomic aspects during rectosigmoid resection, several overview video cameras, surface electromyography (EMG), an ultrasound tracking system (UTS), and a questionnaire were used. In the clinical part of the study, laparoscopic rectosigmoid resections (n = 5) were performed using a curved instrument in the excentral trocar position. The surgeon's left-hand movement and body posture were recorded for further analysis. RESULTS: The curved grasper required the fewest contractions (group 1) of the measured muscles. A comparison of the UTS analysis in the experimental part of the study and the video analysis in the clinical part showed economy of movements in group 1. According to subjective estimation, both physical activity and mental stress remain at the lowest level when the excentral trocar position is used (groups 1 and 2). CONCLUSIONS: The combination of the curved grasper and the excentral trocar position (in relation to the telescope trocar) is, according to our examinations, the best ergonomic adjustment for laparoscopic rectosigmoid surgery.

Experimental assessment of a new mechanical endoscopic solosurgery system: Endofreeze.

BACKGROUND: The assistance received by the surgeon from support personnel during operative laparoscopy is extremely important. This includes retraction of instruments and endoscope positioning. However, human assistance is costly and often does not provide satisfaction for the surgeon. The aim of this study was to develop a mechanical arm capable of allowing easy handling and holding of laparoscopic instruments under the surgeon's control. METHODS: We designed a system, named Endofreeze, based on a particular kinematical construction that maintains an invariant point of constraint motion just above the trocar puncture site through the abdominal wall. The goal was to develop this way a highly intuitive mechanical holding system for laparoscopic instruments, with sufficient precision of action, activated by a single hand movement. We tested a couple of prototypes with different holding arms while performing cholecystectomy in phantom models with swine inserts and compared the results obtained in similar conditions using different holding and positioning systems. RESULTS: The system allows transparent and intuitive operation, and its setup is easy and quick. It may be adapted either as an instrument retractor or as an optic positioning device. Compared to different systems available or prototypes previously tested, such as AESOP 2000, ENDOASSIST, FIPS Endoarm, TISKA Endoarm, and the Martin Arm, in similar conditions, it was more intuitive, allowing shorter time for completion of surgery. CONCLUSION: Endofreeze is a new intuitive mechanical positioning system for endoscopic solo surgery. In phantom models, it demonstrated a shorter time requirement for completion of surgery when compared to other systems available. In our opinion, it represents a valid compromise between human and robotic control for conventional laparoscopic instruments.

Ergonomic testing of two different types of handles via virtual reality simulation.

BACKGROUND: Ergonomics in laparoscopic surgery is an unsolved problem. Deficiencies of the instrument handles are well-known and described in several reports and studies. Today, virtual training modules for laparoscopic surgery are available. The aim of this study was to evaluate the ability of a virtual reality (VR) simulator to determine the ergonomic properties of two different laparoscopic instrument handles. METHODS: Two different types of handles, a ring and an axial handle from Richard Wolf, were used to perform the short clip and cut task of the Xitact 500 LS simulator. The task was repeated every 2 days for a period of 5 weeks. After every trial the volunteers were asked structured questions about their preferences while using the two handles. RESULTS: The axial handle was superior or equal to the ring handle in all criteria. Learning curves over the entire time and day by day were similar. No differences were found for travel distances and error rates, but task times were different for both handles. The subjects preferred the axial handle at the end of the study. CONCLUSION: It is possible to determine differences in ergonomics of handle design with a VR trainer. In this study, the Richard Wolf axial handle was superior to the ring handle.

Monitor position in laparoscopic surgery.

BACKGROUND: One of the key problems in laparoscopy is the ergonomic positioning of the monitor. In this study we tested task performance and muscle strain of subjects in relation to monitor position during laparoscopic surgery. METHODS: Eighteen subjects simulated laparoscopic suturing by threading tiny pearls with a curved needle. This was repeated in three monitor positions (15 min each): frontal at eye level (A), frontal in height of the operating field (B), and 45 degrees to the right side at eye level (C). Subjects were not allowed to turn their heads during these sessions. After the test they were asked for their preferred monitor position. During all tests the electromyographic (EMG) activity of the main neck muscles was recorded and the number of pearls was counted. RESULTS: The EMG activity was significantly lower for position A compared to positions C and B (p < 0.05). No significant difference was found between positions B and C. The number of threaded pearls as an indicator for task performance was highest for position B. The difference was statistically significant compared to position C (p = 0.0008) but not between positions A and C (p = 0.0508) or A and B (p = 0.0575). When asked for the preferred monitor position, nine subjects chose two monitors in the frontal positions A and B. No subject preferred the monitor at the side position (C). CONCLUSION: Regarding EMG data, the monitor positioned frontal at eye level is preferable. Reflecting personal preferences of subjects and task performance, it should be of advantage to place two monitors in front of the surgeon: one in position A for lowest neck strain and the other in position B for difficult tasks with optimal task performance. The monitor position at the side is not advisable.

Local surgical treatment of rectal cancer.

Local surgical treatment of rectal cancer as a curative procedure is only indicated in early rectal cancers. Our indication is T1 low risk cancer according to Hermanek. Conventional transanal procedures are limited to tumours located in the lower rectum and the precision of the excision is restricted by the limitation of the surgeon's visualisation during the procedure. Dorsal approaches show a high rate of complications and should no longer be performed. Transanal endoscopic microsurgery is a technique which has been in clinical use since 1983. By the use of complex technology, precise surgical dissection under a magnified stereoscopic view is possible. With the use of up to three instruments and new instrument technologies, full thickness excision up to segmental resection is possible. The resulting defect is routinely closed at the end of the procedure by a continuous endoscopic suture. The latest results based on 265 tumour resections at the University of Tübingen and 1900 operations based on a German review show positive results. The recurrence rate as a sign of precision of procedure is low and the postoperative complication rate is lower than with conventional procedures.

Robotics and allied technologies in endoscopic surgery.

Endoscopic surgery was developed in the 1970s and 1980s, with initial work conducted by pioneering surgeons. After the development of laparoscopic cholecystectomy, the breakthrough of endoscopic surgery had a great effect on all surgical specialties. Starting with rather simple procedures, such as cholecystectomy, a rapid progression toward more complex procedures, such as reflux or colonic surgery, took place. It was realized at this time that the existing endoscopic instruments allowed only a limited preciseness when performing the procedures, and part of the information from inside the abdominal cavity was not available to the surgeon. This prompted a discussion with engineers concerning the development of more advanced technologies to give those performing endoscopic surgery the same quality of information and manipulation that surgeons have when performing open surgery. These qualities include (1) instruments and manipulators that allow surgical action under endoscopic control with all degrees of freedom; (2) devices that provide surgeons with tactile feedback; and (3) vision systems that provide surgeons with the same quality of visual information as with open surgery, namely, high resolution, excellent color quality, precise spatial information, and a constant clear view for optimal surgical action. At the end of 1999, some of the aforementioned quality concepts found their way into the surgical routine, but most of the concepts are still being developed. Another decade will pass before endoscopic surgery procedures will be closer to the technological goals.

Technique and results of transanal endoscopic microsurgery in early rectal cancer.

The anatomy of the pelvis makes it difficult to perform local excisions in the rectum when the tumor is some distance from the anal verge. We have, therefore, developed a new minimally invasive technique for tumor resection. A rectoscope with a 40-mm diameter permits tumor resection under stereoscopic control in the gas-dilated rectal cavity. Excisions in full-thickness technique up to segmental resections with end-to-end anastomosis can be performed. In selected cases, local excision of a small rectal cancer can be regarded as appropriate treatment. However, most local resections of carcinomas are performed when removal of an adenoma is planned, and the postoperative histology shows a carcinoma. Since 1983, we have operated on 326 patients, 274 who have been enrolled in a prospective clinical trial. Definitive histologic examination proved that 74 of these tumors were carcinomas. The rate of severe complications in patients with carcinomas was 9%, and the mortality rate was 0%. The advantages of this new technique are: The stereoscopic magnified view in the gas-dilated rectum allows precise surgery in an operative field that is otherwise difficult to reach. During the postoperative period, minimal discomfort and pain result in a short hospitalization.

The European experience with laparoscopic cholecystectomy.

A retrospective survey of 7 European centers involving 20 surgeons who undertook 1,236 laparoscopic cholecystectomies was performed. The procedure was completed in 1,191 patients. Conversion to open cholecystectomy was necessary in 45 patients (3.6%) either because of technical difficulty (n = 33), the onset of complications (n = 11), or instrument failure (n = 1). There were no deaths reported, and the total postoperative complication rate was 20 of 1,203 (1.6%), with 9 being serious complications requiring laparotomy. The total incidence of bile duct damage was 4 of 1,203. The median hospital stay was 3 days (range: 1 to 27 days) and the median time to return to full activity after discharge was 11 days (range: 7 to 42 days).

New model for skills assessment and training progress in minimally invasive surgery.

BACKGROUND: With the spread of minimally invasive surgery and training in this field, development of metrics for skills assessment and training progress has become increasingly important. Our approach was to use the tracking of motion for the definition of objectives metrics. METHODS: We have developed an inanimate model and tracked the 3D coordinates of the instrument tips with an ultrasound system. Besides already validated parameters (time, error time, and distance efficiency ratio) we examined the transit and the speed profile for their evidentiary power. Performances of experts (who have already performed >100 laparoscopic operations) and novices (<20 laparoscopic operations) were evaluated. RESULT: The standardized time, the error time as a precision indicator, and the transit profile parameter for spatial perception could significantly ( p < 0.05) distinguish between experts and novices. Furthermore, these parameters and the distance efficiency ratio improved significantly during a training course in laparoscopic surgery. CONCLUSION: Our model showed changes of the mentioned parameters with experience. According to our results, it can be used for skills assessment and as a training progress measurement system. We propose transit profile as an additional important parameter for assessment.

The effect of high-definition imaging on surgical task efficiency in minimally invasive surgery: an experimental comparison between three-dimensional imaging and direct vision through a stereoscopic TEM rectoscope.

BACKGROUND: In 1995, when we first used a high-definition television (HDTV) video system during a laparoscopic cholecystectomy in Tuebingen, we were surprised by the excellence of the spatial impression achieved by an image with improved resolution. Although any improvement in vision systems entails a trade-off among cost, quality, and complexity, high-definition imaging may well become an essential part of 3-D video systems. The aim of this experimental study was to assess the impact of high definition on surgical task efficiency in minimally invasive surgery and to determine whether it is preferable to use a 3-D system or a 2-D system with perfect resolution and color--for instance, HDTV or the three-chip charge-coupled device (3CCD). METHODS: We compared a 3-D video system with the vision through a stereoscopic rectoscope for transanal endoscopic microsurgery (TEM). Because its stereoscopic direct vision is not restricted to either shutter technology or video resolution, TEM optics represents the state of the art. For objective comparison, inanimate phantom models with suturing tasks were set up. The setups allowed the approach of parallel instruments as in TEM operations or via a laparoscopic approach, with oblique instruments coming laterally. Both types of procedure were carried out by highly experienced laparoscopic surgeons as well as those inexperienced in endoscopic surgery. These volunteers worked under 3-D video vision and/or TEM vision. Altogether, the model tasks were performed by 54 different persons. RESULTS: The evaluation did not show a significant (p > 0.05) difference in performance time in all models, but there was a clear trend showing the benefit of a higher resolution. CONCLUSION: We found a tendency for both endoscopically inexperienced and experienced surgeons to benefit from the use of a system with improved resolution (direct vision) rather than a 3-D shutter video system.

Laparoscopic sutured anastomosis of the bowel.

BACKGROUND: Even though the safety and efficacy of sutured anastomosis have been proved in open surgery, laparoscopic sutured anastomosis is rarely performed because it is difficult and time-consuming. We aim at description of a standardized technique for laparoscopic sutured anastomosis of the bowel and definition of its learning curve. METHODS: Fifty-six laparoscopic sutured anastomoses of cow small intestine were performed in a laparoscopic simulator. In a survival animal trial, 10 end-to-end, 2 gastrojejunostomy, 2 cholecystojejunostomy, 2 colocolic, and one side-to-side anastomoses were performed, using the same technique. RESULTS: In the survival cases, we had no leaks or obstruction, minimal adhesions, and only one stenotic gastrojejunostomy. The mean end-to-end anastomotic time was 50 min. The technique was suitable for most sites in the GIT. The learning phase required 40 anastomoses in the simulator. CONCLUSIONS: The described technique seems relatively fast, safe, and universal, and it needs about 40 anastomoses to be mastered.

Robotics and telemanipulation technologies for endoscopic surgery. A review of the ARTEMIS project. Advanced Robotic Telemanipulator for Minimally Invasive Surgery.

In endoscopic surgery, the ability to guide the instrument is significantly decreased compared with open surgery. Rigid laparoscopic instruments offer only four of the six degrees of freedom required for the free handling of objects in space. Robotics technology can be used to restore full mobility of the endoscopic instrument. Therefore, we designed a master-slave manipulator system (ARTEMIS) for laparoscopic surgery as a prototype. The system consists of two robotic arms holding two steerable laparoscopic instruments. These two work units are controlled from a console equipped with two master arms operated by the surgeon. The systems and its components were evaluated experimentally. Laparoscopic manipulations were feasible with the ARTEMIS system. The placement of ligatures and sutures and the handling of catheters were possible in phantom models. The surgical practicability of the system was demonstrated in animal experiments. We conclude that robotic manipulators are feasible for experimental endoscopic surgery. Their clinical application requires further technical development.

The Tübingen balloon. A new method for adjusting the tension of the fundic wrap during laparoscopic Nissen fundoplication.

An adequate fundic wrap is fundamental to the success of conventional and laparoscopic Nissen fundoplications. Nevertheless, up to now there has been no standardized method for the surgeon to determine intraoperatively the width and tension of the fundic wrap according to objective criteria. With the support of Rüsch (Kernen, Germany), we developed a measurement balloon for use in laparoscopic Nissen fundoplication. The balloon allows the surgeon to define the width of the wrap and predetermine its length, as well as to measure its tension. Depending on the measured balloon pressure, the surgeon can perform fundic sutures more or less tightly. On the basis of 41 fundoplication model tests, we found that a fundic wrap typically described as "loose and floppy" produced a balloon pressure of 50-60 mmHg. In 10 laparoscopic Nissen fundoplications on domestic pigs, we were able to adjust the fundic wrap intraoperatively to a balloon pressure in this range (mean; 53.5; SD; 2.25). After the optimal intraoperative balloon pressure in humans has been investigated in a prospective study that is in progress, the Tübingen balloon is expected to serve as an instrument for quality assurance in reflux surgery.

A new remote-controlled endoscope positioning system for endoscopic solo surgery. The FIPS endoarm.

In the field of endoscopic solo surgery, the assistance received by the surgeon from ergonomical positioning devices is extremely important. They aid in both the retracting of instruments and the positioning of the endoscope. However, passive systems derived from open surgery have not proved satisfactory. Therefore, we set out to develop a remote-controlled arm capable of moving a rigid endoscope with about four degrees of freedom, while maintaining an invariant point of constraint motion coincident with the trocar puncture site through the abdominal wall. The system is driven by means of speaker-independent voice control or a finger-ring joystick clipped onto the instrument shaft close to the handle. When the joystick is used, the motion of the endoscope is controlled by the fingertip of the operating surgeon, which is inserted into the small ring of the controller in such a way as to make the motion of the fingertip correspond directly to the motion of the tip of the endoscope. A study was performed to compare the two different interfaces available for the system. With both interfaces, the guiding system allows for transparent and intuitive operation. Its set-up is easy; it is safe and reliable to use during the intervention; and it is faster than human assistance. With its improved ergonomy, this new generation of remote-controlled endoscope positioning system represents a further step toward the diffusion of solo surgery techniques in minimally invasive therapy. In our opinion, this prototype creates a valid compromise between human and robotic control of rigid endoscopes.

Transanal endoscopic microsurgery.

Transanal endoscopic microsurgery, although technically challenging, offers a viable and perhaps superior outcome to radical abdominal or traditional transanal excision of rectal neoplasia. Appropriate training and case selection, as with any new technology, are mandatory to help ensure optimal results.