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Biomedical subjects

G Buess

Publications and source records attributed to G Buess.

At least 19 recordsLinked to original sources

[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.

Cholecystectomy

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.

Adenoma

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.

Adenoma

In vitro fragmentation of gallstones with lithotriptors for use in laparoscopic cholecystotomy.

In preliminary in vitro experiments, five different lithotriptors for use in laparoscopic cholecystotomy were tested to determine the fragmentation time and rate of a defined group of gallstones. The Alexandrit laser and the ultrasonic lithotriptor were too ineffective to warrant further investigation. In phantom tests with pig gallbladders, the pulsed dye laser and the electrohydraulic lithotriptor had a fragmentation rate of 100%, but the rate of clearing of the gallbladder was 0% as stone debris always remained in the gallbladder. The clearing rate of the RotoLith mechanical lithotriptor was 84.6%. The RotoLith lithotriptor was the most effective device because the stones were ground into such small particles that they could easily be rinsed out of the gallbladder. As the RotoLith procedure does not need to be monitored optically, the opening of the gallbladder need not exceed 3 mm compared to 10 mm for the other lithotriptors. This makes closure of the gallbladder safer and it would seem feasible to perform the procedure using the RothoLith lithotriptor under local anaesthesia.

Animals

The laparoscopic approach to modified Taylor's procedure in the treatment of chronic duodenal ulcer: an improved technique.

Laparoscopic modified Taylor's procedure for chronic duodenal ulcer was performed in three patients. A new, specially developed combination instrument allowed the operation to be performed easily, sometimes using only four introduction sites. Coagulation, suction, and rinsing can be performed at the same time, and the hook knife, scissors, or different forceps can be introduced through the operating channel of the instrument. An overcast seam to approximate the seromyotomy was done using the technique developed for transanal endoscopic microsurgery. Instead of the silver clips, specially handmade steel and titanium clips were used to fix the PDS suture. No major postoperative complications occurred. The gastric acid output under basal condition and stimulation showed a decrease ranging from 47% to 79%. Endoscopic examination performed on the 4th postoperative week showed complete recovery in all cases.

Adult

[Laparoscopic cholecystectomy: new evaluation of a surgical method in the light of endoscopic techniques].

The laparoscopic cholecystotomy was developed to remove calculi while preserving a functioning gallbladder. 120 phantom tests on pig's gallbladders were performed. No major complications were observed in 20 animal experiments with pigs. Compared with competing conservative and interventional methods the laparoscopic cholecystotomy provides immediate removal of stones and a definite closure of the gallbladder by a clip. Calcified stones are no contraindication for the procedure. After introduction into the clinical routine, an outpatient treatment in local anaesthesia seems to be possible. Patients with a high operative risk should be treated by this method. The laparoscopic cholecystotomy represents an alternative to the percutaneous transhepatic litholysis and the ESWL.

Anesthesia, Local

Experimental laparoscopic cholecystotomy.

This instrument set for a single puncture technique of laparoscopic cholecystotomy was developed in 100 phantom tests with pig gallbladders and was later evaluated in 12 animal experiments. No complications were observed. After clinical development, treatment on an outpatient basis under local anaesthesia seems possible. For the patient this would mean avoiding general anaesthesia, shorter hospitalization, pain reduction and good cosmetic results, while reducing expenditure for the public health authorities at the same time. To avoid recurrent stones, diet and low-dose drug therapy should be considered. Because the procedure is minimally invasive, repetition of the laparoscopic procedure seems justified if stones recur.

Animals

Elevated plasma histamine concentration as a sensitive real-time parameter for distinct phases of surgical trauma: a tool for technology assessment.

High technology plays an important role in surgery, either to expand surgical procedures or to reduce tissue trauma, which is a main goal of minimum invasive surgery. Due to the tremendous increase of costs the problem of technology assessment will not only be solved by statistical methods, but also by biomedical considerations and laboratory tests. Histamine release could be an indication for tissue trauma, which is caused directly by tissue damage or indirectly by infection or hypoxia. Therefore histamine release was investigated during different phases of operation in two clinically very important and complex situations: resection of liver metastases of colorectal carcinoma and resection of the oesophagus because of an oesophageal carcinoma. To model this situation in animal experiments, two randomized controlled studies were conducted in sheep. Traditional techniques were compared with techniques of minimum invasive surgery. Plasma histamine levels were determined at well-defined phases of the operation. Histamine release was demonstrated at distinct phases of operation indicating considerable specificity of this parameter, if sensitivity is guaranteed by advanced tests. Incision of the liver capsule by thermocauterization, liver ischaemia, tissue trauma in more extended disruption of perioesophageal tissue were causes of more extended histamine release. It is concluded that measurement of plasma histamine is a suitable indicator for discriminating between extended and minimum invasive surgery. The consequence of considering this parameter may be less complications in the post-operative period and a short hospital stay with better quality of life.

Animals

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).

Adolescent

[Transanal microsurgery].

The system for TEM consists of a rectoscope of 40 mm diameter, stereoscopic optics and up to four surgical instruments for simultaneous application. Operation is performed under automatic gas distension. Since 1983 we have operated upon 332 patients, 280 of whom were analyzed in a prospective clinical trial. The complication rate was below 10%, mortality 0.3% and the recurrence rate ot the adenomas 4%. Compared to the conventional surgical procedures, postoperative pain is significantly lower and hospital stay and rehabilitation time are shorter.

Equipment Design

[Training program for minimally invasive surgery].

Currently 'Minimally Invasive Surgery' (MIS) is rapidly finding a widening range of applications and increasing numbers of surgical departments start with new MIS techniques. Surgical work under endoscopic control requires an intensive readjustment to operation technique bringing about new problems in training. We believe that intensive training of MIS procedures on suitable training phantoms should be a prerequisite for clinical application of MIS and therefore have established a training center for MIS in Tübingen, FRG, offering weekly hands on training courses for different procedures.

Curriculum

[Intrarectal ultrasonography in the preoperative assessment of the depth of infiltration of rectal tumors].

From June 1987 to February 1990, 142 out of 319 patients with rectal tumours were investigated by ultrasound scanning with the object of ascertaining the depth to which the tumour had infiltrated. This examination proved completely feasible in 130 of these patients (84 men, 46 women, mean age 61.7 [42-84] years). Postoperative histological examination revealed an adenoma (n = 59) or a T1 carcinoma (n = 19), while intrarectal ultrasonography disclosed the same findings in 79 patients (true-positive in 75 cases). A T2-tumour was diagnosed by histological examination in 24 patients, and by ultrasonography in 22 (true-positive in 18 cases). The histological diagnosis of a tumour in stage T3 or T4 (n = 27) was in close agreement with the ultrasound findings (n = 24). The positive predictive value of ultrasonography ranged between 0.94 and 0.97 depending on the staging of the tumour, and the sensitivity between 0.75 and 0.96. Preoperative ultrasonographic determination of the depth of invasion of a rectal tumour enables the surgeon to devise a therapeutic plan to suit the individual patient's needs; one option may be local excision.

Adenoma

[Endoscopic microsurgical dissection of the esophagus: a contribution to the reduction of pulmonary complications following esophageal resection? A comparative animal experiment study].

A new endoscopic microsurgical technique for dissection of the esophagus has been developed and tried out in animals. With this technique the esophagus is dissected and removed via a cervical approach by means of a new operating endoscope. In a randomized animal study we compared endoscopic versus blunt dissection and versus abdominothoracic resection. During endoscopic dissection we saw significantly lower bleeding and no laceration of the pleural cavity or damage to the recurrent laryngeal or to the vagus nerve. Significant changes of hemodynamics or gas exchange were observed in the blunt dissection group: increase of heart frequency, decrease of arterial pressure and decrease of paO2. In contrast these parameters did not change in the endoscopic group.

Animals

[Endosonographic staging of rectal tumors].

Pre-operative staging was performed in 81 patients with rectal tumours by means of endorectal sonography. In 87% of cases (70 out of 81), the endosonographic findings corresponded with the histopathological appearance; the recognition of T0 and 1 tumours, which is important in deciding surgical procedures, was possible in 94% (51 out of 54). Differentiation between T0 and T1 tumours (i.e. between adenomas and carcinomas infiltrating the submucosa) was not possible. Five out of ten of T2 and 14 out of 16 T3 tumours were staged correctly. One T4 tumour was placed in too low a stage. A comparison of the echo structure of adenomas and carcinomas in 76 patients showed that 28 out of 43 adenomas (65%) have homogeneous echoes, while 24 out of 33 carcinomas (73%) showed inhomogeneous low intensity echoes.

Adult