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Biomedical subjects

G F Buess

Publications and source records attributed to G F Buess.

At least 19 recordsLinked to original sources
PubMed2000

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.

Endoscopy↗
PubMed2000

Experimental trial on solo surgery for minimally invasive therapy: comparison of different systems in a phantom model.

BACKGROUND: Robotic aid in minimally invasive surgery (MIS) is becoming more and more common. We designed an experimental trial in a phantom model to verify the feasibility of solo surgery for MIS. By performing laparoscopic cholecystectomy on a phantom model, we compared combinations of different systems available in terms of safety, comfort, and time requirements. METHODS: Two surgeons skilled in endoscopic procedures tested the following systems as endoscope holders: the robotic system (AESOP), foot-controlled (AESOP 1000), and voice-controlled (AESOP 2000); the remote controlled FIPS Endoarm, electrically driven and controlled by a finger-ring joystic; the passive system TISKA Endoarm, a mechanical arm moved by hand and fixed by electromagnetical brakes. All of these systems combined with a second TISKA Endoarm as an instrument holder. A combination of two mechanical Martin arms, c, also was tested. The results were compared with those from a control group involving an assistant surgeon. A total of 70 experiments were performed. RESULTS: The shortest dissection time was registered by the combination of two TISKA Endoarms, with a statistically significant difference as compared with the control group (p < 0.05) and experiments using AESOP 1000 (p < 0.05). The TISKA Endoarm also proved to be more comfortable when used as an instrument holder (p < 0.001 vs Martin arm), and rated second only to AESOP 2000 as an endoscope holder. The rating of AESOP 2000 as endoscope holder was significantly higher than that of all other groups (p < 0.001). The study proved the feasibility of solo surgery. The time needed for dissection was shortest when two TISKA Endoarms were used, demonstrating the possible advantages of solo surgery. The TISKA Endoarm received a subjective positive rating when used as both endoscope holder and instrument holder. The voice control of AESOP 2000 seemed to be a major improvement in the development of an optimal man-machine interface. Nevertheless, the system presents considerable space requirements and does not supply control of 30 degrees optics. The principle of the finger-ring joystick adopted by the FIPS Endoarm seemed very intuitive but lacking in ergonomy. CONCLUSION: Laparoscopic solo surgery can be considered a safe procedure, although further technologic developments should lead to improved ergonomy, intuitiveness of handling, and architecture of the systems, offering the surgeon better control, increased precision of action, and reduction in operation time.

Minimally Invasive Surgical Procedures↗
PubMed2000

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.

Animals↗
PubMed2000

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.

Animals↗
PubMed2000

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.

Efficiency↗
PubMed2000

[Positioning systems for endoscopic solo surgery].

BACKGROUND: Endoscopic surgery has acquired undisputed importance in the field of both general and specialised surgery. The introduction of robotic technology in surgery has recently led to the development of new positioning systems for endoscopic surgery. These allow direct control of the endoscopic procedures by the surgeon, whose vision currently depends on the assistant in charge of positioning the optic camera in compliance with his wishes. METHODS: We experimented different positioning systems for optics and rigid endoscopic instruments for laparoscopy, some of which were our own design. Over 400 cholecystectomies were carried out by six different surgeons on phantoms containing animal organs. The experimental systems were AESOP (Computer Motion, USA), with both foot-pedal and voice control, ENDOASSIST (Armstrong Healthcare Co. UK), controlled by a device worn by the surgeon, FIPS Endoarm (Karlsruhe Research Centre, Germany), controlled by a joystick and voice, and the passive TISKA Endoarm system (Karlsruhe Research Centre, Germany). Combinations of two systems were compared, using one to position the optic and one to position the retractor instrument. RESULTS: Phantom tests, which are preferable owing to constant conditions, showed the feasibility of experiments in Solo Surgery conditions and highlighted the advantages and drawbacks of the various systems. In particular, the surgeons appreciated the intuitive use of the TISKA Endoarm system as a positioner for the retractor instrument and the optics, in spite of the fact that it was only a passive movement apparatus. Among the remote-control systems tested as an optics positioner, FIPS Endoarm controlled by a joystick was particularly intuitive and produced the best results in terms of time taken to complete the procedure. The time taken was even shorter than that in a large control group with human assistance. CONCLUSIONS: In our experience endoscopic Solo Surgery was found to be applicable to clinical practice. This will bring numerous advantages in terms of the precision of surgical procedures and savings in terms of time and human resources, with a consequent reduction of management costs. There is no doubt that this method represents a step forward in the application of technology to surgery.

Endoscopes↗
PubMed1999

Trocar and instrument positioning system TISKA. An assist device for endoscopic solo surgery.

The assistance received by the surgeon from support personnel during surgical laparoscopy is extremely important. This includes the retracting of instruments and the positioning of the endoscope. However, human assistance is costly and often does not provide satisfaction for the surgeon. The aim of the project was to develop a mechanical arm capable of manipulating a laparoscopic instrument under the control of the operating surgeon. The system design is based on a particular kinematic construction that maintains an invariant point of constraint motion coincident with the trocar puncture site through the abdominal wall. The guidance 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. A new generation of instrument positioning systems, with improved ergonomy, will be a first step toward the diffusion of solo surgery techniques in minimally invasive therapy. We believe this prototype represents a valid compromise between human and robotic control for conventional laparoscopic instruments.

Animals↗
PubMed1999

Three-dimensional (3-D) video systems: bi-channel or single-channel optics?

BACKGROUND AND STUDY AIMS: This paper presents the results of a comparison between two different three-dimensional (3-D) video systems, one with single-channel optics, the other with bi-channel optics. The latter integrates two lens systems, each transferring one half of the stereoscopic image; the former uses only one lens system, similar to a two-dimensional (2-D) endoscope, which transfers the complete stereoscopic picture. MATERIAL AND METHODS: In our training centre for minimally invasive surgery, surgeons were involved in basic and advanced laparoscopic courses using both a 2-D system and the two 3-D video systems. They completed analog scale questionnaires in order to record a subjective impression of the relative convenience of operating in 2-D and 3-D vision, and to identify perceived deficiencies in the 3-D system. As an objective test, different experimental tasks were developed, in order to measure performance times and to count pre-defined errors made while using the two 3-D video systems and the 2-D system. RESULTS AND CONCLUSION: Using the bi-channel optical system, the surgeon has a heightened spatial perception, and can work faster and more safely than with a single-channel system. However, single-channel optics allow the use of an angulated endoscope, and the free rotation of the optics relative to the camera, which is necessary for some operative applications.

Cholecystectomy, Laparoscopic↗
PubMed1999

Robotics and systems technology for advanced endoscopic procedures: experiences in general surgery.

The advent of endoscopic techniques changed surgery in many regards. This paper intends to describe an overview about technologies to facilitate endoscopic surgery. The systems described have been developed for the use in general surgery, but an easy application also in the field of cardiac surgery seems realistic. The introduction of system technology and robotic technology enables today to design a highly ergonomic solo-surgery platform. To relief the surgeon from fatigue we developed a new chair dedicated to the functional needs of endoscopic surgery. The foot pedals for high frequency, suction and irrigation are integrated into the basis of the chair. The chair is driven by electric motors controlled with an additional foot pedal joystick to achieve the desired position in the OR. A major enhancement for endoscopic technology is the introduction of robotic technology to design assisting devices for solo-surgery and manipulators for microsurgical instrumentation. A further step in the employment of robotic technology is the design of 'master-slave manipulators' to provide the surgeon with additional degrees of freedom of instrumentation. In 1996 a first prototype of an endoscopic manipulator system. named ARTEMIS, could be used in experimental applications. The system consists of a user station (master) and an instrument station (slave). The surgeon sits at a console which integrates endoscopic monitors, communication facilities and two master devices to control the two slave arms which are mounted to the operating table. Clinical use of the system, however, will require further development in the area of slave mechanics and the control system. Finally the implementation of telecommunication technology in combination with robotic instruments will open new frontiers, such as teleconsulting, teleassistance and telemanipulation.

Equipment Design↗
PubMed1999

Ergonomic surgeon's chair for use during minimally invasive surgery.

The characteristic working situation in laparoscopic surgery involves elongated instruments and limited mobility of the surgeon during the operation. These circumstances require new technical solutions to enhance the surgeon's comfort. In other surgical fields with special ergonomic situations, such as microsurgery, some surgeons prefer to operate from a seated position at the operating room table. We developed a new surgeon's chair dedicated to the ergonomic and functional requirements of laparoscopic surgery. The chair allows the surgeon to maintain a semi-standing position during the operation. Foot pedals for high frequency and suction/irrigation are integrated into the base of the chair. The pedals are purposely aligned to be comparable to foot pedals in a car. The chair is driven by electromotors, controlled with a special foot switch that operates independent of assisting personnel during surgery. Initial clinical testing of the chair could prove the theory that supporting the surgeon with a cockpit type of operating room chair helps to avoid fatigue during long endoscopic procedures. Such assistance is especially important in combination with robotic devices for use during solo surgery.

Equipment Design↗
PubMed1998

Comparative study of two-dimensional and three-dimensional vision systems for minimally invasive surgery.

BACKGROUND: The aim of this comparative study was to gain subjective and objective data to determine for which operative tasks three-dimensional (3-D) vision systems are superior to two-dimensional (2-D) systems and to demonstrate any advantages or disadvantages of 3-D systems. METHODS: A model with five standardized tasks including sewing and knotting was developed to objectively measure performance times and to count technical faults. In our training center for minimally invasive surgery, surgeons involved in basic and advanced laparoscopic courses trained using both 2-D and 3-D vision systems. They subsequently completed analog scale questionnaires to record a subjective impression of comparative ease of operation tasks under 2-D and 3-D vision and to identify perceived deficiencies in the 3-D system. RESULTS: Compared to 2-D vision, the objective performance time was significantly shorter and significantly less mistakes were made using 3-D vision. All operative tasks were subjectively judged significantly easier under 3-D vision. CONCLUSIONS: Users with a normal capability for spatial perception can perform standard tasks more quickly and safely using 3-D vision, and a greater benefit is apparent for more complicated surgical maneuvers.

Depth Perception↗
PubMed1997

[Value of training courses in minimally invasive surgery].

The actual situation regarding the education für MIS requires the optimisation and standardisation of the training system. This paper presents the results of an inquiry about the evaluation of the course of operative laparoscopy. 80-90% of those interviewed made the comments "very good" and "good", with regard to the imparting of the theoretic foundation of the technique of endoscopic operations, for sufficient possibility of manual training and for the realistic setting of the animal organ model compared with the clinical operation. Because of our experience, we recommend attending such training courses before starting laparoscopic operations.

Attitude of Health Personnel↗
PubMed1997

[Optics with natural appearing added illumination].

Today's endoscopes use a central frontal illumination which creates huge contrast, no visible shadows, and gives an unnaturally flat impression. In the SIMIC project, a new type of optics has been developed that uses additional illumination fibres ending 3 mm behind the front lens. This gives a more natural and spatial impression of the body cavity, causes shadows that are an improvement when approaching tissue with an instrument, reduces blooming in the foreground, and improves detail reproduction in the background.

Endoscopes↗
PubMed1996

Functional results after transanal endoscopic microsurgery.

PURPOSE: Compared with traditional operations, superior results after transanal endoscopic microsurgery (TEM) for rectal tumors have been demonstrated in terms of morbidity and mortality. However, no data were available on functional outcome after TEM. We, therefore, studied 42 patients who were undergoing TEM. METHODS: Patients were examined by anorectal manometry and participated in a standardized interview preoperatively and three months and one year after surgery. RESULTS: Anorectal function as assessed by manometry was impaired three months after surgery but improved again during the first postoperative year. In parallel, some patients complained of impaired continence or defecation disorders in the interview three months postoperatively. These functions improved during the first year after surgery, too. CONCLUSIONS: Correct comparison of our results with functional outcome after anterior rectal resection is impossible. We feel, however, that functional results after TEM are likely to be superior to those after anterior resection for rectal tumors.

Adenoma, Villous↗
PubMed1996

[Comparative study of various 2-D and 3-D vision systems in minimally invasive surgery].

The aim of this comparative study was to gain subjective and objective data to determine for which operative tasks it is useful to work with 3-D rather than 2-D vision systems and to show the advantages and disadvantages of 3-D systems. A series of five standardized tasks like sewing and tying knots was set up to measure performance times objectively and to count errors. Compared with 2-D vision, the performance time was 32% shorter and 43% fewer errors were made under 3-D vision (P < 0.001). In our endoscopic training centre, surgeons involved in basic and advanced laparoscopic courses trained using both 2-D and 3-D vision systems. They subsequently completed analogue scale questionnaires to record a subjective impression of comparative ease of operation tasks under 2-D and 3-D vision, and to identify perceived deficiencies in the 3-D system. In both courses, all operative tasks were judged significantly easier under 3-D vision (P < 0.001). It was concluded that users with a normal capacity for spatial perception can work faster and safer under 3-D vision, especially for more complicated surgical manoeuvres.

Animals↗
PubMed1996

Prospective study of the proctographic and functional consequences of transanal endoscopic microsurgery.

A prospective study of clinical, manometric and proctographic results in 36 patients presenting for transanal endoscopic microsurgery was performed. Anorectal manometry showed no difference in maximal squeeze pressure before and 12 months after operation, but resting pressures were lower after surgery (mean(s.e.m.) preoperative 86.1(27.6) mmHg versus postoperative 67.2(23.2) mmHg, P < 0.05). The rectoanal inhibitory reflex was lost in a significant group of patients (reflex present in 34 of 36 patients before operation and in 27 of 36 12 months after operation, P < 0.05). Proctography, manometry and questionnaire showed preserved function of most modalities 12 months after operation such that if objective function was impaired clinical function was adequate.

Adult↗
PubMed1996

[Comparative study of endoscopic 2-D and 3-D imaging systems].

The aim of this comparative study is to gain subjective and objective data to determine for which operative task it is more useful to work with 3-D than 2-D vision systems, in order to show the advantages and disadvantages of 3-D systems. A parcour with five standardized tasks, e.g., sewing and knotting, were built to measure performance times objectively and to count faults. Compared to 2-D vision the performance time was 32% shorter and 43% less faults were made under 3-D vision (p < 0.001). In our endoscopy training centre, surgeons involved in basic and advanced laparoscopy courses were trained to use both 2-D and 3-D vision systems. They subsequently completed analogue scale questionnaires to record a subjective impression of comparative ease of operative tasks under 2-D and 3-D vision, and to identify perceived deficiencies in the 3-D system. In both course, all operative tasks were judged significantly easier under 3-D vision (p < 0.001). It was concluded that users with a normal capability for spatial perception can work faster and safer under 3-D vision, especially for more complicated surgical manoeuvres.

Attitude of Health Personnel↗