Showing papers in "Endoscopic surgery and allied technologies in 1995"

Access techniques: Veress needle--initial blind trocar insertion versus open laparoscopy with the Hasson trocar.

Abstract: The two most common techniques used to gain entry into the peritoneal cavity during laparoscopic general surgery are the blind Veress needle/trocar insertion and open trocar placement under direct visualisation. Once entry to the peritoneal cavity has been achieved, gas insufflation is used to establish pneumoperitoneum and enable visualisation of abdominal structures. Many of the complications associated with operative laparoscopy arise from creation of the pneumoperitoneum, such as subcutaneous emphysema and gas embolism, or from injury to internal structures during abdominal entry. Because of the relative infancy of laparoscopic general surgery, much of the information relating to these types of complications are associated with minimally invasive gynaecologic procedures. Compared to gynaecologic laparoscopy, general surgical interventions are typically more complicated, require longer operative times and a greater number of access sites, and are more likely to be performed in older patients. Therefore, complication rates associated with pneumoperitoneum or abdominal entry may actually turn out to be higher for laparoscopic general surgery, making selection of a blind versus open access technique more important. Two direct comparisons of these access approaches in laparoscopic cholecystectomy indicated that an open technique employing a peritoneal cut-down and trocar insertion under direct visualisation was safer than blind insertion of the Veress needle and primary trocar. We also favour the open access technique, believing that the risk for serious visceral or vascular complications is less than that with a blind approach.

Quantitative standardised analysis of advanced laparoscopic surgical procedures.

Abstract: To support the improvement of advanced laparoscopic surgical procedures, we designed a quantitative analysis method to monitor surgical activities. The emphasis lies on the time spent on these activities and on the instruments controlled by the hands of the surgeon. Our method uses combined video images originating from the laparoscope, an overview CCD camera placed in the operating theatre and, when available, a video colonoscope. After the operation is finished, the images are evaluated by means of a standardised analysis routine based on a spreadsheet program and a set of standard terms (thesaurus), to minimise subjectivity of the analysis. After calculations, the data are presented in tables and graphs, resulting in objective information for research on the operation. Seven advanced laparoscopic procedures, in this case colon resections, have been analysed, and it was demonstrated that the analysis method is capable of describing different laparoscopic procedures using the limited thesaurus. Possible areas of application of the method are the evaluation of time-consuming parts of the operation, of surgical tasks and measurement of the surgeon's learning curve. Other applications are the prediction and measurement of the impact of new instruments and techniques.

The optical "Veress-needle"--initial puncture with a minioptic.

Abstract: Laparoscopic access is a necessary part of minimally invasive surgery. The double blind puncture with Veress-needle and trocar can cause lethal complications such as bowel injury, bleeding and gas-embolisation. Some authors have reported alternative techniques for laparoscopic abdominal access. Because no blind procedure can absolutely prevent injury, permanent visual control of perforated tissue layers as in open surgery should be achieved to prevent possible injury at an early stage. Previously described procedures could not fulfil all requirements to comply with this ideal, i.e. permanent visual control of abdominal wall penetration prior to establishment of pneumoperitoneum and trocar insertion without further possible damage. We designed a 2 mm fibreglass optic 250 mm in length that is inserted into a suitable cannula. Special construction allows rinsing through the cannula to clear the vision and to open spaces in the puncture track by water dissection. After incision of the skin, all layers of the abdominal wall can be visualised, including blood vessels and internal surfaces. Once the abdominal cavity is reached, the needle tip is retracted and a two-step dilation allows the trocar to be introduced via the puncture track. Only then does insufflation begin. The fibreglass optic-equipped safety needle was used for visually controlled access in 184 laparoscopic surgical procedures. After a period of training, all layers of the abdominal wall could be recognised exactly. In two patients with dense adhesions, perforation of the small bowel was diagnosed immediately by endoscopic viewing. The small injury needed no treatment, and the intended procedure was completed laparoscopically.(ABSTRACT TRUNCATED AT 250 WORDS)

Endoscopic retropubic colposuspension: "Retziusscopy" versus laparoscopy--a reasonable enlargement of the operative spectrum in the management of recurrent stress incontinence?

Abstract: The technical feasibility of the laparoscopic and extraperitoneal approach to the Burch colposuspension for treatment of grade II and III (moderate to severe) stress incontinence was examined in a randomised prospective study. Irrespective of the endoscopic access, two suspension techniques, namely conventional suture and stapler fixation of alloplastic materials, were compared. A total of 20 patients entered this preliminary evaluation. Three complications occurred; a bladder perforation (during laparoscopic dissection of the space of Retzius), a postoperative detrusor instability and transient urinary retention. Both the endoscopic approaches and the suspension procedures employed proved feasible and safe, and presented the advantages of a "minimal access" procedure, with short hospitalisation and rapid recovery. Short-term follow-up (6-12 months) showed subjective and objective results comparable to those of the conventional abdominal Burch colposuspension. Detailed evaluation of the subgroups is not yet feasible, as the number of patients in this preliminary evaluation was too small and follow-up too short. Final evaluation of the entire study population and long-term follow-up will be necessary before these procedures can be generally offered as a therapeutic alternative.

Image-guided access techniques.

Abstract: For increasing safety in access and guidance of endoscopes and instruments, fast real-time radiologic imaging should be integrated. Open designed Magnetic Resonance Imaging (MRI), Computer Tomography (CT), and Electron Beam Tomography (EBT) scanners permit adequate transparency of the operative field. CT and EBT as hybrid scanners can be combined with fluoroscopy. MRI avoids X-ray exposure and entails the possibility of 3D localisation, while open access and keyhole imaging allows nearly real-time guidance of instruments. EBT has the largest gantry (90 cm) for using long instruments, and the image acquisition requires only 50 msec (34 images/sec at 8 levels). However, computed reconstruction of the data takes about 3 times longer than conventional CT. Until EBT can be accelerated, CT will be the golden standard of guidance-techniques in high risk areas, because the tips of the instruments can be precisely visualised within +/- 0.5 mm (MRI: 3.5 mm). MRI-guidance can be used for low risk access techniques. This safe interactive transparent guidance technique has the potential to reduce complications, and it adds significant advantages to micro-invasive operative procedures such as percutaneous diskectomies, pain and cancer therapy with ethanol, or gene-technology implants in the new field of "surgical tomography".

Haemodynamic changes during laparoscopic cholecystectomy in the high-risk patient.

Abstract: Although laparoscopic cholecystectomy (LC) has become the standard surgical procedure for the treatment of gall stones, the question has still to be answered whether it is safe for critically ill patients with cardiac disease. 20 ASA-class III/IV patients were monitored during LC by means of a Swan-Ganz catheter. Commencement of anaesthesia led to a significant decrease of mean arterial pressure, cardiac index, stroke volume index and left ventricular stroke work index. Increasing intra-abdominal pressure by insufflation of CO2 and surgical stimuli during gall bladder dissection induced an increase of pulmonary arterial occlusion pressure mean pulmonary artery pressure and central venous pressure (p = 0.05). Mean arterial pressure, cardiac index, stroke volume index and left ventricular stroke work index remained below pre-induction values (p < 0.05). In 13 patients with high filling pressures the administration of nitroglycerine improved all parameters. In the post-anaesthetic care unit all parameters had returned towards baseline. In conclusion, LC may lead to temporary myocardial insufficiency. Nevertheless, LC seems to be safe provided that pathological alterations are recognised and treated.

Endoscopically controlled trocar and cannula insertion.

Abstract: One of the keys to safe laparoscopic or thoracoscopic surgery is an expeditious and reliable access to the region of interest. To minimise the risk of accidental injury to major vessels, lung, intestine and other important structures the principle of controlled visualised access has been advocated. This 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". The direct visualisation of an active, controllable penetration of the abdominal wall is expected to become indispensable. A selected variety of endoscopically assisted trocar and cannula systems such as the "windowed trocar", the "optical trocar", the "Visiport" and the "optical scalpel" are described.

Helium insufflation in laparoscopic surgery.

Abstract: Carbon dioxide is the most commonly used gas for abdominal insufflation in laparoscopy today. Due to the solubility of carbon dioxide large volumes are absorbed into the circulation causing a high PCO2 and a low pH (respiratory acidosis). Carbon dioxide is also stored in several sites in the body and is released at the conclusion of the procedure prolonging the respiratory acidosis when the patient is least able to cope with this additional burden. Cardiac effects of CO2 consist of a lowering of the arrhythmia threshold, increased blood pressure, pulse and cardiac output. At a sustained high level this can lead to cardiac depression and death. These effects are particularly prone to occur in cardiac and respiratory cripples. Other gases that have been used include air, oxygen, nitrous oxide and nitrogen. Their use has been discontinued because of the danger of embolism. Air, oxygen and nitrous oxide are also not safe to use in the presence of electrosurgical instruments thereby limiting their usefulness even further. Helium has been proposed as a very promising alternative to CO2. In the laboratory and in a clinical trial, helium has not produced the respiratory acidosis associated with CO2 insufflation. This is further evidence that the acidosis is not primarily due to elevation of the diaphragm and consequent increased dead space, but to the large amount of CO2 that is absorbed directly from the peritoneal cavity. Helium would seem to be the gas of choice at this time as it comes close to fitting the criteria for an ideal insufflating gas. Helium is clear and colorless, allowing unimpeded vision to the operator. It is non toxic, not flammable or explosive and can be safely used with electrocautery and laser. Helium is easy to handle and not very soluble which decreases the amount absorbed from the peritoneal cavity and consequently the amount used. That which is absorbed is quickly cleared by the lungs. Helium is metabolically inactive (in contrast to CO2) and does not interfere with normal metabolic processes. In view of this promising initial work, further studies are indicated.

Laparoscopic creation of a neovagina: modified Vecchietti method.

Abstract: A new surgical technique for the treatment of vaginal aplasia is described. It consists of a modification of Vecchietti's method, allowing laparoscopic performance of the operation. 9 patients have been treated in this way since January, 1991 with good results. No complications were seen. Being virtually atraumatic, this method requires only brief hospitalisation, which is of vital importance in view of the psychological and physical problems this particular condition entails. Results are identical, so that this technique should always take precedence over the conventional Vecchietti method.

Vaginal vault suspension.

Abstract: A laparoscopic approach to significant pelvic relaxation and vault prolapse, including technical aspects of the procedures involved and an anatomic rationale for the laparoscopic approach, are described. The results demonstrate good clinical outcomes in addition to low intraoperative and post operative morbidity. It is concluded that the laparoscopic approach to vault support has a superior result when compared to open vaginal alternatives.

Cutting versus conical tip designs.

Abstract: The history of development in laparoscopy shows that the dilemma involving blind insertion of the trocar has not changed in over 100 years. Perforation of the abdominal wall with the cutting trocar is no longer necessary with today's anatomical and technical possibilities. The cutting trocar with its four cutting surfaces has a great disadvantage compared to the conical trocar with regard to safety. The linea alba should not be disrupted, and perforation of the abdominal wall should be performed in an area where the fascia is weaker and muscle is more abundant. The "z"-track method of trocar insertion prevents intestinal or omental herniation. For perforation and stretching of the muscle, a conical trocar with a blunt tip is recommended. After inserting the conical trocar down to the layer of subcutaneous fat or muscle, further advancement is performed under visual control using a normal straight endoscope and by rotating the bevelled end of the trocar sheath. Perforation of the abdominal wall with a conical trocar using the "z"-track incision under endoscopic control prevents incisional herniation of intestine or omentum.

The gasless laparoscopic cholecystectomy.

Abstract: The pneumoperitoneum, generally used for all laparoscopic procedures, can lead to specific disadvantages and result in complications, and it furthermore represents a restriction of the surgeon's freedom of movement. In July, 1993 we started doing laparoscopic surgery without the pneumoperitoneum. Under direct vision and digital control, a fan-shaped wall retractor, which is attached to an electric lift arm, is introduced into the abdominal cavity. After raising the abdominal wall, the scope is introduced through the same access and the laparoscopic procedure can be started without the technical and pathophysiological problems which may occur when using a pneumoperitoneum. In this gasless laparoscopic procedure, simple valveless trocars and instruments can be used. During anaesthesia, neither an increased ventilation nor an enlarged ventilation pressure is necessary in this way we performed gasless laparoscopic cholecystectomy in 50 patients. We observed 5 wound infections as related complications. We had to change the surgical procedure seven times. The retraction technique creates a sufficient but not optimal exposure to the gallbladder. Intraoperative changes of the instruments, suction and specimen removal appeared easier. Both conventional and laparoscopic surgical instruments were introduced through the valveless trocars. Our experience demonstrates the practicability of this technique and potential advantages.

Retroperitoneal surgery of the kidney, ureter and adrenal gland.

Abstract: Seventy-one retroperitoneal endoscopic procedures on the kidney, ureter and adrenal gland were performed in 69 patients, using the balloon technique of retroperitoneoscopy. There were 9 failures in this series, all of which were converted into an open procedure. The balloon satisfactorily dissected the kidney and the ureter in 59 patients (85%). There were no major complications and the minor complication rate was 20%. Forty-nine patients were discharged the next day, while 20 were kept in hospital for 2 to 5 days. The balloon technique of retroperitoneoscopy is safe, simple and reliable for exposing the kidney, ureter and the adrenal gland.

Extraperitoneal pelvic and para-aortic lymphadenectomy.

Abstract: Many laparoscopic surgeons, particularly in urology, have been performing a laparoscopic transperitoneal pelvic and para-aortic lymphadenectomy for prostatic and germ cell cancers respectively with great success. The transperitoneal route has been superceded by an extraperitoneal approach. Although the working space is sometimes a little more restricted and orientation more difficult, the ultimate result is a procedure associated with much less post-operative pain.

OREST II--ergonomic workplace and systems platform for endoscopic technologies.

Abstract: Endoscopic interventions require a multitude of technical devices, like gas-insufflators, cameras, light sources, high-frequency scalpels and others. The devices available today represent stand-alone "function-insulas" from the view-point of systems technique. They have to be placed in the operating theatre and set-up right before each specific intervention. From each of these single devices supplies, cables and hoses lead to the body of the patient and have to be connected on both sides within the sterile and the non-sterile field. This not only requires a long setup time in the OR but also restricts the mobility of the operative personnel. Besides the ergonomic and the hygienic weakness of the contemporary solution, significant functional problems limit the efficiency of the OR environment. One of the major drawbacks lies in the lack of direct control of the devices by the surgeon and the confusing display of parameters and technical status. Against this background the systematic revision of the current endo-surgical workplace appears to be a major requirement for further technical and surgical progress. As a result of close cooperation between surgeons and engineers a systems workplace for minimally invasive surgery, OREST, has been developed and clinically tested. It integrates all devices into a mobile cabinet. The single devices are connected to a central computer and can be remote controlled directly by the surgeon from the table. A special display continuously informs about the system status. The lines and cables are guided into the sterile field by means of a swivel arm from one side of the patient. Multi-plugs are used to connect all lines at a central terminal within the sterile area. Clinical application of the first prototype OREST I started in 1993. OREST II is now available as a series product. Further development is focused on the integration of advanced sub-systems like tactile devices and advanced vision system.

Variance of cardiorespiratory parameters during gynaecological surgery with CO2-pneumoperitoneum.

Abstract: Laparoscopic procedures with CO2-pneumoperitoneum are used widely in gynaecology and surgery. The effects of a 15 degrees head-down position, different intra-abdominal pressures (IAP) and CO2-insufflation flows on cardiorespiratory parameters were studied prospectively in 18 gyneacologic patients under general anaesthesia. The 15 degrees head-down position led to significant changes in heart rate (-6%) and in central venous pressure (+53%). Furthermore, significant changes under commonly used conditions for gynaecological laparoscopy (IAP 9mmHg, CO2-insufflation flow 2.41/ min., 15 degrees head-down position) were found in heart rate (+16%), systolic blood pressure (+21%), diastolic blood pressure (+26%), central venous pressure (+57%), peak inspiratory pressure (+26%), end-tidal CO2-concentration (+19%), central venous pCO2 (+21%), and central venous pH (-7%). On examination of variable pressure and insufflation flows (IAP 3, 9, and 15mmHg; CO2-insufflation flows 1.2, 2.4, and 6.0 1/min.), increasing changes in heart rate (7% - 24%), diastolic blood pressure (22% - 33%), central venous pressure (30% - 59%) and peak inspiratory pressure (10% - 43%) correlated with increasing IAP. However, they were independent of CO2-insufflation flows. The results demonstrate that CO2-pneumoperitoneum causes marked changes in cardiorespiratory parameters, but these do not exceed levels commonly regarded as safe in ASA class I and II patients.

Subtotal hysterectomy revisited.

Abstract: The advent of laparoscopic surgery has enabled gynaecologists to re-evaluate the traditional approaches to hysterectomy. Until the 1940's hysterectomy involved retaining the cervix because the simpler operation avoided damage to the ureter and prevented ascending infection, which was an important consideration before the advent of antibiotics. In order to reduce the risk of developing cervical carcinoma the cervix was traditionally removed at hysterectomy over the last 50 years. Since it is possible to remove the area where cervical carcinoma develops and with the development of an effective screening programme for cervical carcinoma, this needs no longer to be a consideration. A more logical approach to laparoscopic hysterectomy would be to retain the cervix but remove the transformation zone and in so doing there is less risk to the ureter, less postoperative urinary dysfunction, virtually no disturbance to the lower genital tract, thus resulting in little or no impairment of sexual enjoyment.

Retroperitoneal endoscopic lumbar sympathectomy: laboratory and clinical experience.

Abstract: Retroperitoneal endoscopic lumbar sympathectomy was performed in four pigs in the prone or lateral position to study the feasibility of these new approaches. Positioning, port placement and the dissection technique are described in detail. In nine patients retroperitoneal endoscopic lumbar sympathectomy, using the lateral position technique, was performed. The importance of port placement and dissection techniques for visualisation of the sympathetic chain are emphasised. The endoscopic retroperitoneal approach enables the sympathetic chain to be accurately localised whilst enhanced endoscopic vision aids dissection. Retroperitoneal endoscopic lumbar sympathectomy is a feasible technique offering patients the benefits of the minimally invasive approach.

Laparoscopic bladder neck suspension.

Abstract: The preferred therapy for genuine stress incontinence is surgery. The Burch procedure is considered by many to be the gold standard for surgical treatment of genuine stress incontinence. The Burch procedure requires the elevation of the anterior wall of the vagina to the level of the origin of the paravaginal fascia by suspension from Cooper's ligaments (iliopectineal ligaments). A properly performed Burch procedure cures 93 percent. The laparoscopic performance of the Burch procedure results in a decrease in the length of hospital stay, faster recovery, and less scarring due to the smaller incisions. In a consecutive series of thirty patients the average length of stay in hospital was thirty-six hours and the patients were able to return to non-stressful regular activities within one week of surgery. There were no conversions to the open Burch procedure. Intraoperative and postoperative complications included one electrocautery injury of the bladder requiring laparoscopic suture reinforcement of the bladder and three weeks of bladder drainage, three episodes of transient detrusor instability requiring medical therapy for two months, and two episodes of urinary retention requiring bladder drainage for two weeks. The laparoscopic procedure provides results similar to the open operation if a meticulous technique is used.

Multifunctional instrument for operative laparoscopy: technical, experimental and clinical results in gynaecology.

Abstract: Whilst endoscopic surgical procedures are getting increasingly more complex, in the various surgical disciplines mono- and bifunctional instruments are only slowly being replaced by multifunctional ones. Therefore a complex, intelligent system was developed, the central part of which is a multifunctional instrument. All basic functions necessary for surgical laparoscopy are integrated and comprise: cutting electrodes (unipolar and bipolar) which can be advanced or retracted pneumatically; coagulation forceps with mechanical control; and irrigation and suction devices. All 5 mm instruments can be used and there is an option for others, such as laser or aqua-dissection. The various functions are controlled via the handle of the multifunctional instrument which is connected to the electronic control unit, the MULTILAP system, which supplies the energy, material, and information flow required. In vivo standardised experiments in pigs were first performed to test the new instrument. Operation time was reduced by more than 20% when compared with the same procedure performed conventionally, during which frequent changing of instruments was necessary. Clinical application, without complications in all 30 patients (uterus preserving procedures or reconstructive tubo-ovarian surgery) confirmed the advantages of a multifunctional device, with optimised cutting and coagulation of vessels more than 1-2 mm in diameter, and reduced duration of operation. Safety and ergonomics were improved. Thus, an electronically controlled instrument with multifunctional working channels for lasers, ultrasound appliances, or mechanical instruments is available for application in all domains of operative laparoscopy.

Principles of development and design of microsystems.

Abstract: The state of the art in microsystem design and fabrication is reviewed. The focus is on silicon micromachining, which uses the equipment and processes of IC-technology to produce highly miniaturized, three-dimensional structures, sensors and actuators for various biomedical applications. The micro components can be integrated into surgical instruments, catheters and implants. Thus new functions and a higher level of intelligence are created. Portable microsystems are being developed for chemical analysis and biomedical monitoring. The cultivation and investigation of live cells on chip substrates offers encouraging perspectives for the future.

Overview of extraperitoneal laparoscopy.

Abstract: Recent developments in extraperitoneal endoscopic techniques are causing a second wave of excitement amongst laparoscopic surgeons. In certain situations, there are definite advantages over an intraperitoneal alternative but the new interest of many surgeons for whom this has always been a more natural open route is also very welcome and timely. Many of the frustrating problems of access into the extraperitoneal space have been overcome by the introduction of an expanding dissecting balloon which both creates an adequate working space and tamponades potentially small haemorrhagic vessels torn in the dissection. Routine laparoscopic techniques can then take over using carbon dioxide for insufflation. The major advantage for the patient seems to be reduced post-operative pain but the major problem facing the surgeon is one of orientation in a space where there are no recognisable anatomical landmarks. This problem is being overcome with adjuvant radiological techniques.

Preoperative morbidity and anaesthesia-related negative events in patients undergoing conventional or laparoscopic cholecystectomy.

Abstract: Laparoscopic cholecystectomy is the standard method for surgical treatment of non-malignant gall bladder disease. Well tolerated in otherwise healthy patients, it remains however, questionable whether the laparoscopic procedure in patients with severe pre-existing morbidity is associated with a higher incidence of negative intraoperative events than open cholecystectomy. Therefore, the incidence of negative intraoperative events was prospectively investigated in a series of 1,367 patients (319 with open cholecystectomy and 1,048 with laparoscopic cholecystectomy) who were analysed for occurrence of events such as hypertension, hypotension, arrhythmia, unusual bleeding and transfusion requirement, regurgitation or aspiration of gastric content and respiratory disorders. For further analysis the patients undergoing each operative procedure were divided into two subgroups with either preoperative ASA physical status I and II or III and IV. The study groups were comparable in sex and age. There were no intraoperative deaths. The frequency of hypertension, hypotension or arrhythmia alone and in combination was similar in both groups. The need for intervention was significantly more frequent in ASA class I/II patients with laparoscopic cholecystectomy. Respiratory disorders were rare. There was a significantly higher incidence of postoperative ventilatory support in patients with conventional cholecystectomy. Transfusion was required significantly less often in patients with laparoscopic cholecystectomy (0.19% versus 15.36%). CO2-pneumoperitoneum led to severe circulatory alterations in 7 healthy patients. The most severe negative event was a cardiac arrest in 1 female patient who was successfully resuscitated without any sequelae. In ASA-class III and IV patients intraoperative negative events were equally frequent and independent of the procedure. Severe preoperative morbidity per se seems to be no contraindication for laparoscopic cholecystectomy.

Alternative techniques for laparoscopic tissue anastomosis in the retroperitoneum.

Abstract: Operative retroperitoneoscopy provides a less traumatic alternative to transperitoneal laparoscopy for the minimal access surgery of retroperitoneal structures. Although open and closed techniques have been described for achieving access, the former allows the creation of a larger initial retroperitoneal workspace with a greater margin of safety and in a shorter space of time.

The abdominal lift: is there any advantage for the critically ill patient?

Abstract: The use of carbon dioxide to create a cavity for the operation of laparoscopic cholecystectomy leads to serious complications of the cardiovascular system; consequently, patients with ischaemic heart disease can be put at greater risk. For example, on reaching an intra-abdominal pressure of 15mmHg, a fall of about 35% of the static compliance was observed. Upon using the Laparolift, these influences on the respiratory system were not detected, and the rise in systemic vascular resistance usually seen with the CO2-pneumoperitoneum did not occur. From the anaesthetist's viewpoint the Laparolift was helpful in the treatment of patients with serious limitations of cardiac function.

Endoscopic capsulotomy by means of laser--a new therapeutic method in cases of capsular contracture.

Abstract: The laser endoscopic capsular technique is a new method introduced to treat patients who develop capsular contracture after the insertion of a breast prosthesis. A capsuloscope was developed in co-operation with M. Boebel (Richard Wolf) to undertake the procedure. Twenty patients have undergone 25 capsulotomies. The technique relieved pain, corrected the deformity and reduced hardness.

Disposable versus reusable instruments in laparoscopic cholecystectomy. A prospective, randomised study.

Abstract: We quantified and compared the advantages and disadvantages of disposable and reusable laparoscopic instruments in a prospective, randomised study of 158 cholecystectomies. The patients were randomly divided into two groups: 80 underwent surgery with reusable instruments, 78 with disposable instruments. The following parameters were recorded in both groups: duration of surgery, number of complications, technical problems during surgery, rate of conversion to open surgery, subjective postoperative pain, postoperative hospitalisation time, length of inability to work, and postoperative evaluation by the operating room personnel. No overall differences were found in subjective pain, postoperative complications, postoperative hospitalisation time, or time before returning to work. Surgery with disposable instruments was on the whole faster, with fewer conversions to open surgery, but this was statistically non-significant. Reusable instruments were associated with a statistically significant increase in the rate of intraoperative, instrument-related difficulties. In spite of longer operation times and higher personnel costs with reusable instruments, we found that cholecystectomy with reusable instruments costs an average of 1,015 DM less per procedure.

Experimental retroperitoneal endoscopic surgery.

Abstract: Techniques for retroperitoneal endoscopic procedures with the patient in prone position were evaluated in experimental studies in the pig. Nephrectomy, para-aortic lymph node dissection, lumbar sympathectomy and assisted aorto-femoral bypass were performed and the experience is reported herein. The prone position contributes to the creation of the retroperitoneal working space and eliminates the need for extensive retraction and thus for additional ports. The modified open Hasson technique was found to be the preferred retroperitoneal access procedure.

Vacuum-supported endoscopic access.

Abstract: The rapid increase in the number of endoscopic operations performed has resulted in a corresponding rise in the incidence of severe complications. This issue has generated widespread concern at recent congresses. It is now indisputable that safer access to the abdominal cavity is required. We have developed a technique of vacuum-supported visual access which allows the surgeon to anticipate dangerous sites of access and avoid injuries to internal organs or retroperitoneal blood vessels. The procedure has two major advantages: Firstly, a pre-peritoneal approach allows the surgeon to visualise the structures behind the peritoneum, and secondly, puncture of the insufflation-needle is facilitated and the depth of insertion is minimised. The underlying principle is to use negative pressure to elevate the peritoneum. Using this approach, the principles of open surgery are adhered to during abdominal access, thereby avoiding visceral injury.

Principles of multimodal imaging

Abstract: SummaryThe aim of ‘multimodal imaging’ is to combine, handle and visualize information from various sources (X-ray film, ultrasound, CT, MR, signals like ECG and EEG, laboratory results, medical records). Diagnosis, treatment as well as training and continued education demands an integrated view of this information. This paper defines the requirements for: (1) interfacing the modalities; (ii) registration and modality/modality matching based on reference models; (Mi) user interface design; and (iv) data management including access control.