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Biomedical subjects

G Buess

Publications and source records attributed to G Buess.

121 records · Page 7Linked to original sources
PubMed1980

[Problem in indication and artificial ventilation during segmental resection of the trachea (author's transl)].

Based on clinical experience and lung function data (bronchial resistance and inspiratory and expiratory FEV1) obtained in experiments with stenosis in the front of the mouth, bronchial resistance and inspiratory and expiratory FEV1 should first be determined. Resection of tracheal stenosis is indicated at a bronchial resistance of more than 5 cm H2O/1/s. This corresponds to a stenosis diameter of less than 8 mm. In the case of carinal resection, one lung can be ventilated by artifical respiration for a short time only. The data obtained during resection confirm the well-known requirement of clamping the opposite pulmonary artery.

Airway Resistance↗
PubMed1979

Surgical treatment of tracheal stenosis.

During the last 3 1/2 years 8 patients underwent segmental resection of the trachea and one patient underwent resection of the carina at the Department of Surgery, University Hospital, Köln. Follow-up investigation in 6 month intervals showed good results in 6 patients. The complicated course of 1 of our patients with tumor infiltration of the trachea is discussed. In this case a large esophagotracheal fistula was covered with a vascularized esophageal segment. Suggestions for surgical indications in segmental resection of benign esophageal stenosis are outlined.

Adolescent↗
PubMed1979

[Indications for the correction of tracheal stenosis caused by prolonged artificial ventilation of polytraumatized persons (author's transl)].

Pronounced, short-length narrowing of the trachea combined with dyspnoea at rest is an absolute indication for partial resection. For stenoses of moderate degree the indications for surgical intervention are as yet not clearly defined. They depend not only on the clinical, roentgenological and tracheobronchoscopic findings, but also on the results of lung function tests. Changes in respiratory function become noticeable at reduction of under 30% of the tracheal diameter. Experiments with artificially induced stenosis have shown an exponential rise in flow resistance when the diameter of the trachea was narrowed to below 8 millimetre. observations made in patients have proved that the experimental results also apply clinically. The indications for surgery of a tracheal stenosis should be made dependent on the results of the determinations of flow resistance, whole body plethysmography and expiratory and inspiratory volume/1 sec. Flow resistance exceeding 5 cm H2O/1 sec, equivalent to narrowing to under 8 mm in diameter, is considered to be an indication for partial resection.

Humans↗
PubMed1977

[Polycystic degeneration of parenchymatous organs in the abdomen or malignant tumour? Computer tomographic investigations].

The report deals with the computer tomographic investigation of a space-occupying intra-abdominal process in which there were polycystic lesions of the liver, kidneys and pancreas. CT scanning combined with biochemical investigations provided clear proof of the presence of cysts, their morphology and extent. The possibility of the neoplasm could be excluded; it proved unnecessary to carry out any invasive procedures and a laparotomy also became unneccessary.

Abdominal Neoplasms↗
PubMedDate not supplied

LaparoLith. A new instrument for stone fragmentation in laparoscopic cholecystectomy.

Laparoscopic cholecystectomy can be performed with incisions of a maximum diameter of 10 mm. The removal of a stone-filled gallbladder at the end of an operation via the 10-mm port needs often-extensive tissue-consuming manipulations for stone removal or minilaparotomy. Stone fragmentation can be achieved by mechanical crushing and by ultrasound-, electrohydraulic-, and tunable dye laser lithotripsy. The clinical employment of the LaparoLith (Baxter Healthcare Corporation), an instrument which allows mechanical fragmentation of stones inside the gallbladder, is presented here. We have used the LaparoLith in nine patients and have been successful in stone fragmentation in seven of these. The LaparoLith seems to be helpful in laparoscopic cholecystectomy, preventing extension of the subnavel incision.

Cholecystectomy, Laparoscopic↗
PubMedDate not supplied

[Shadow optic. An endoscope with optimized ligth].

Modern endoscopes use a single mid-frontal illumination source that yields an unnatural flat image. At the University of Tübingen, in collaboration with Gimmi GmbH (Tuttlingen, Germany), a new concept endoscope has been developed with an additional light source: the shadow optic. With the aid of a secondary light source along the axis of the endoscope, a shadow is obtained which gives an impression of spatial depth. The aim of the study was to assess this new endoscope objectively, focusing on the speed and safety of the surgical act. The shadow optic was used in an experimental setting by 20 probands, each of whom performed five different standardized procedures of increasing difficulty five times, with and without shadow optic in randomized sequence, making a total of 1000 experiments. The procedures consisted in spatial orientation tests, structure-surrounding maneuvers, tissue clamping, needle puncture and suturing. The evaluation criteria were the time required to perform the procedures and the number of predefined errors as determined by electronic control. In each procedure, the time needed to perform the experiments was shorter with the shadow optic, reductions of up to 18% being recorded, and the number of errors was up to 54% lower compared to the experiments conducted with the traditional endoscope. The results of the study demonstrate that, as a result of the more natural spatial view conditions, the procedures were performed faster and with greater precision when the shadow optic was used. The endoscopic imaging with the shadow optic makes for better spatial orientation and a more natural and manageable image.

Endoscopes↗
PubMedDate not supplied

Histologic effects of different technologies for dissection in endoscopic surgery: Nd:YAG laser, high frequency and water-jet.

Precise cutting combined with reliable coagulation of the margins of the lesion is an important requirement for dissection techniques in endoscopic surgery. These requirements are met by the two most common ancillary energy sources applied for endoscopic dissection today, electrosurgery and "thermal lasers", mostly the Nd:YAG. For the comparison of the histological effects of monopolar and bipolar high frequency with the Nd:YAG laser an experimental in vitro and in vivo study has been performed. In order to evaluate the advantages of non thermal dissection for endoscopic procedures, a water jet cutting system was included in the in vitro study. In parenchymatous tissue the water jet was found to be the least traumatic technique, followed by bipolar high frequency, laser and monopolar high frequency. The water jet was not applicable for intestinal dissection since uncontrolled bloating of the rectal wall with uncontrolled disruption of the tissue layers occurred. A general disadvantage is that secure haemostasis in the line of incision is hard to achieve. In the microscopic comparison of the shape of the incision, the Nd:YAG laser produced the smoothest lesions with well-defined margins. The monopolar technique was more often associated with irregular and sometimes fissured margins. These results were confirmed in the in vivo part of the study (Transanal Endoscopic Microsurgery).

Animals↗
PubMedDate not supplied

Wittmoser's technique of thoracoscopic sympathectomy and vagotomy.

His extensive developmental and clinical work made Raimund Wittmoser a major trailblazer in endoscopic surgery from the 1950s on. His single-puncture technique for operative thoracoscopy permitted surgical interventions of peerless quality on the sympathetic and vagal nerves. His basic surgical principle was to achieve the greatest possible selectivity by a segmental approach to the sympathetic rami communicantes or the individual branches of the vagus nerve. Besides his extraordinary surgical skills, his particular achievement was the development of new instrumental and ancillary technologies for endoscopic surgery. In addition to the development of new endoscopes and imaging systems, his pressure-regulated CO2 insufflation system and low frequency cautery technique had major impact on the further development of endoscopic surgery. Finally, Wittmoser's surgical interventions in the autonomic nervous system were of outstanding quality and set standards still observed by thoracoscopic surgeons today.

Germany↗
PubMedDate not supplied

Development of steerable instruments for minimal invasive surgery in modular conception.

The augmenting complexity of minimal invasive interventions requests a continuous improvement of technologies. Extended endoscopic procedures, e.g. laparoscopic-transanal sigmoidectomy or thoracoscopic esophagus dissection require difficult surgical manipulations like mobilisation, sceletonization as well as ligatures and sutures. They are difficult to perform with the present endo-surgical instruments. A major instrumental weakness is represented by the restricted steerability because of the rigid shaft axis and the resulting low degrees of freedom (DOF). Therefore a series of steerable flexible instruments has been developed in interdisciplinary cooperation between surgeons and engineers. The prototypes provide a multi-joint working as the instrument's elbow, which allows to incline the tip around +/- 280 degrees. The second additional DOF is the rotation of the surgical tool. The prototypes have been experimentally tested in laparoscopy and thoracoscopy, showing a clear improvement in the carrying out of complex operative manipulations. The further development is performed in modular conception, including electric drives.

Animals↗
PubMedDate not supplied

Endoscopic microsurgical dissection of the esophagus (EMDE).

This paper presents endoscopic microsurgical dissection of the esophagus (EMDE), a surgical technique for the therapy of esophageal cancer which improves blunt esophageal dissection with the aim of reducing postoperative morbidity and mortality. A mediastinoscope with integrated operative instrument channel, fibre bundles, optic and rinsing channel has been developed whereby precise and atraumatic esophageal dissection is possible via a cervical access incision. Between 1989 and 1993, 37 patients were operated on using the EMDE technique and are compared with 48 patients operated on during the same period by the thoraco-abdominal route. The operative duration was reduced by the new technique, and although the number of severe complications was not significantly different between both groups, the rate of pulmonary and cardiac complications was reduced. The mortality rate was 10% for EMDE patients and 14% for the thoraco-abdominal procedure, and there was no difference in the long-term survival rate. As distinct from procedures requiring a thoracotomy for esophageal dissection, EMDE permits ventilation of both lungs throughout the entire operation and reduces the total operative trauma.

Dissection↗