Biomedical subjects
G Buess
Publications and source records attributed to G Buess.
Experimental development in colorectal surgery.
A one year research programme on endoscopic colorectal resections was carried out at the University of Tübingen. Two research lines were planned: the development of the required technologies and the development of the surgical procedure. During the research programme on technologies a new device provided with an air proof system for transanal insertion of the anvil of a divisible stapler and a new technique for closure of the colonic and rectal stumps (cable binding technique) were developed. Such technological innovations enabled the authors to accomplish a new combined laparoscopic-rectoscopic procedure which was performed according to four different variants in a series of 32 animals. The last 15 consecutive successful cases, performed according to the definitive procedure, represented a standardized animal trial before starting the clinical investigation.
State of the art of laparoscopic colorectal surgery.
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3-D video techniques in endoscopic surgery.
Three-dimensional visualisation of the operative field is an important requisite for precise and fast handling of open surgical operations. Up to now it has only been possible to display a two-dimensional image on the monitor during endoscopic procedures. The increasing complexity of minimal invasive interventions requires endoscopic suturing and ligatures of larger vessels which are difficult to perform without the impression of space. Three-dimensional vision therefore may decrease the operative risk, accelerate interventions and widen the operative spectrum. In April 1992 a 3-D video system developed at the Nuclear Research Center Karlsruhe, Germany (IAI Institute) was applied in various animal experimental procedures and clinically in laparoscopic cholecystectomy. The system works with a single monitor and active high-speed shutter glasses. Our first trials with this new 3-D imaging system clearly showed a facilitation of complex surgical manoeuvres like mobilisation of organs, preparation in the deep space and suture techniques. The 3-D-system introduced in this article will enter the market in 1993 (Opticon Co., Karlsruhe, Germany.
Visually controlled trocar insertion by means of the "optical scalpel".
The importance of a safer approach to the abdominal cavity has led to several developments in the field of trocars, cannulae and puncture techniques. Examples are the insertion of a needle scope into a Veress needle, complex access cannulae and our new principle of using an "optical scalpel". In our view, direct optical visualization and actively controllable penetration of the abdominal wall are mandatory. First experimental and clinical applications indicate the newly developed "optical scalpel" (Olympus Winter & Ibe, Hamburg, Germany) as a reliable and useful instrument for a safe approach to the endoscopic operative field. This instrument was successfully used in 10 endoscopic operations and is currently undergoing further clinical testing.
Technique and preliminary results of laparoscopic cardiomyotomy.
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Laparoscopic treatment of common bile duct stones. Phantom experiments using electrohydraulic and pulsed dye laser lithotripsy.
To evaluate the feasibility of laparoscopic transcystic lithotripsy of common bile duct stones, a phantom model comprising bovine liver and biliary tract tissue integrated within a laparoscopic trainer was built. A 9 French cholangioscope was introduced via the cystic duct into the common bile duct in which a human gall stone of known composition had been introduced. Lithotripsy was performed using either a laser or electrohydraulic probe passed through the working channel of the cholangioscope following which the stone fragments were manipulated into the duodenum through the papilla of Vater using the choledochoscope. A total of 20 lithotripsies with each energy form were performed. Lithotripsy was successful in breaking the stones into fragments smaller than 6 mm. The energy expenditure was comparable with a mean of 49 J for laser lithotripsy (range 9 to 159 J), and 53 J (range 16 to 160 J) for electrohydraulic wave lithotripsy. The lithotripsy time measured from introduction of the cholangioscope until its removal was a mean of 30 minutes for electrohydraulic wave lithotripsy and 41 minutes for dye laser lithotripsy. This difference was statistically significant. Macroscopic tissue damage to the common bile duct wall was not observed following any procedure. An additional experiment was performed to evaluate damage that could be caused to the wall of the common bile duct. Both electrohydraulic shock wave and pulsed dye laser lithotripsy without optical feedback regulation caused severe tissue defects when there was tissue contact or distance less than 2 mm. With optical feedback regulation however, no tissue damage was induced by laser lithotripsy.(ABSTRACT TRUNCATED AT 250 WORDS)
Intelligent surgical instrument system ISIS. Concept and preliminary experimental application of components and prototypes.
The recent progress in endoscopic surgery, which is highlighted by the complexity of fundoplication, stomach surgery and colorectal surgery, has revealed major restrictions with difficult surgical manipulations. Mobilisation, dissection and suturing techniques are hampered mainly by the limited degrees of freedom of the conventional rigid instruments (translation along and rotation around the longitudinal axis and the limited play in the access channel). The frequent interchange of instruments such as coagulation forceps, scissors and suction-irrigation probe is time-consuming. We have established an interdisciplinary development model with the aim of improving surgical technology, instrument systems, the operation theatre and its environment. Concepts of electronic instrument control and sensoric feedback, and the features of the surgical man-machine-interface are described. The first prototypes of an intelligent steerable instrument system, ISIS, and its optional effectors, e.g. semiautomatic sewing device and multifunctional coagulation instrument, were tested in phantom and animal experiments. System analysis will lead to specially designed operating theatres (minimal invasive surgical operating system MINOS).
Potential applications of microsystems engineering in minimal invasive surgery.
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[Endoscopic surgery of the upper gastrointestinal tract].
Clinical application of laparoscopic cholecystectomy was followed by a lot of other endoscopic procedures for the surgical treatment of diseases of the upper gastrointestinal tract. In cases of disorders of esophageal motility traditional procedures can be performed endoscopically. Remarkable experiences were published concerning the cardiomyotomy, and fundoplication. Endoscopic operations could be shown to be a suitable treatment of benign and malignant tumours of the esophagus. Also the nowadays very rarely indicated vagotomy can be performed laparoscopically having good results. During the last year a few new operations could be added by using endoscopic linear staplers for resections and anastomoses such as gastostomies, jejunostomies, gastroenterostomies and even BII resections. In general surgeons are enabled to perform a great variety of procedures by the use of endoscopic techniques.
[Minimally invasive surgery of the colon and rectum].
In the period from 1.8.89 to 1.7.92 140 adenomas and 63 carcinomas were locally resected from the rectosigmoid area with the instruments of TEM. The mortality was 0.5%, the rate of dehiscence of the suture 9.8%. 75% of these were treated conservatively. One of the 29 patients with locally resected pTl-low risk-carcinoma developed a recurrence so far. The rate of recurrent adenomas was 1.4%. From 7.1.1992 to 24.5.1993 21 procedures in colorectal surgery were performed laparoscopically or in a combined laparoscopic transanal operation. The mortality was zero. 1 case of suture dehiscence, 2 cases of crural phlebothrombosis and 1 lesion of the left ureter were observed. The use of TEM in the combined procedure means an extension of the range of minimally invasive colorectal surgery to the lower rectum.
Laparoscopic fenestration of a lymphocele following combined pancreas-kidney transplantation.
The development of a lymphocele is an uncommon but well-known complication following a kidney transplantation. In case of recurrence after puncture and aspiration, a laparoscopic procedure seems to be the treatment of choice. For the preoperative workup ultrasound is essential; CT scan is to be favored if available. A large fenestration is easy to perform laparoscopically and thus the lymphocele is drained into the abdominal cavity. Because of the immunosuppressive treatment, adhesions hindering a laparoscopic approach are unusual. The conclusion is that surgeons trained in laparoscopic techniques have an important role in these infrequent abdominal problems.
[Intraoperative cardiopulmonary disorders during esophagectomy in relation to the surgical technique].
Twenty-one healthy female sheep were anaesthetised in a standard technique with ketamine, dehydrobenzperidol and etomidate. In seven sheep an endoscopic esophagectomy was made (group 1), in seven a blunt esophagectomy (group 2) and in a further seven a thoraco-abdominal esophagectomy (group 3). ECG monitoring, invasive blood pressure measurement, measurement of the central venous pressure and the pulmonary artery pressure with estimation of cardiac output, arterial and mixed venous blood gas analyses were made. The measurement times were: ZDM 1 = preoperative, ZDM 2 = after laparotomy, ZDM 3 = after cervical esophagus preparation or thoracotomy, ZDM 4 = after esophagectomy, ZDM 5 = after inflation of the lungs and ZDM 6 = after a second exploration of the esophagus bed (only groups 1 and 2). Finally the sheep in groups 1 and 2 were thoracotomised on the right side. In group 1 the measurement parameters remained largely unchanged during the entire experiment. In group 2 significant and by the end of the operation irreversible pathological changes occurred immediately after the blunt esophagus resection (ZDM 4): decrease of MAP, paO2 and CO, increase of AaDO2 and PVR. In group 3 similar changes were observed, they began, however, during ZDM 3. The measurement results can be explained in accordance with the operative anatomical findings. How far postoperative pulmonary complications can be avoided in patients with the endoscopic technique must be demonstrated in clinical use.
[Perspectives of minimally invasive surgery in the area of the head and neck].
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[Laparoscopic cholecystectomy].
Laparoscopic cholecystectomy has been accepted clinically in a very short time. Following an intensive training-course for manual dexterity clinical experience should be achieved in carefully selected cases. After a certain number of cholecystectomies the majority of cholecystectomies can be performed laparoscopically. The complication rate of laparoscopic cholecystectomy in the hand of a well trained surgeon seams to be comparable or even smaller than in conventional procedure. The patients have significantly less pain and bodily activity starts early. The postoperative time in hospital in our clinic is two to three days. The rehabilitation-time could be shortened.
Transanal endoscopic microsurgery.
Transanal endoscopic microsurgery (TEM) has emerged as a minimally invasive means of resecting rectal tumors. Developed in Germany and now being used with increasing frequency in the United States, TEM utilizes a 40-mm operating rectoscope, which is sealed with an airtight facepiece. Carbon dioxide is constantly infused, thereby distending the rectum and maintaining visibility. A variety of instruments, such as tissue graspers, a high-frequency knife, suction, and needle holders, are inserted through the facepiece. Adenomas that are small, large, or even circumferential, as well as selected carcinomas up to 24 cm, can be removed with TEM instrumentation. The optics provide sixfold magnification, and this, combined with the constantly distended operative field, allows for a precise excision of the tumor as well as closure of the wound. For lesions in the mid and upper rectum, TEM is an alternative to a transsacral or transabdominal approach, with subsequently shorter hospital stay and fewer complications.
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.
EUS-guided therapy in rectal tumors and other fields of minimal invasive surgery.
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