Search

Recent developments in 3D reconstructions can enhance the quality and diagnostic value of axial 2D image data sets with direct benefits for clinical practice. To show the possible advantages of a hybrid rendering method [color-coded 3D shaded-surface display (SSD)- and volume rendering method] with the possibility of virtual endoscopy we have specifically highlighted the use in relation to the middle and inner ear structures. We examined 12 patients with both normal findings and postoperative changes, using image data sets from high-resolution spiral computed tomography (HRSCT). The middle and inner ear was segmented using an interactive threshold interval density volume-growing method and visualized with a color-coded SSD rendering method. The temporal bone was visualized using a transparent volume rendering method. The 3D- and virtual reconstructions were compared with the axial 2D source images. The evaluated middle and inner ear structures could be seen in their complete form and correct topographical relationship, and the 3D- and virtual reconstructions indicated an improved representation and spatial orientation of these structures. A hybrid and virtual endoscopic method could add information and improve the value of imaging in the diagnosis and management of patients with middle or inner ear diseases making the understanding and interpretation of axial 2D CT image data sets easier. The introduction of an improved rendering algorithm aids radiological diagnostics, medical education, surgical planning, surgical training, and postoperative assessment.

The article is preceded by an introduction to world-wide communication networks. Some important basic features are explained. The major impact is on temporary and future aspects of the Internet for psychiatry. A variety of advantages in World Wide Web telemedicine for patients, clients, psychotherapists, clinicians and scientists are extensively demonstrated. Useful and established possibilities are discussed. Finally, the risks of this kind of communication are shown and listed.

Laparoscopic or retroperitoneoscopic interventions such as nephrectomy or tumor nephrectomy call for the removal of large quantities of tissue, which can no longer be extracted via the relatively confined lumen of a cannula. For this purpose, a variety of organ retrieval systems have been designed and are commercially available with the aim of safe tissue retrieval. This paper summarizes the results of an experimental and clinical comparison of the most important organ entrapment systems suitable for endoscopic nephrectomy. The LapSacs was the first organ bag especially designed for laparoscopic nephrectomy. Despite various new modifications of this entrapment system, it still represents one of the best alternatives and has been used worldwide with success. However, because of its simplicity, it requires a certain laparoscopic expertise and involves a learning curve. Newly developed retrieval systems (i.e., LapBag, Extraction Bag, Endo-Catch) offer some advantages regarding the handling of the bag, which may be particularly useful during retroperitoneoscopic nephrectomy with a restricted working space. Retrieval systems (i.e., Endobag, Endopouch) with low resistance to tearing forces or permeability to tumor cells or bacteria (i.e., Espiner Bag) cannot be recommended for endoscopic nephrectomy.

Der retroperitoneale Zugang findet breite Anwendung bei offenen Operationen in der Urologie. Mit Einfuhrung der Ballondissektionstechnik konnte dieser anatomische Zugang auch fur laparoskopische Operationen genutzt werden. Material und Methode: Zwischen 12/1992 und 10/1997 wurden 200 retroperitoneale Operationen an 197 Patienten (Alter 4–82 Jahre) durchgefuhrt: 78 Nephrektomien, 50 Nierencystenresektionen, 14 Nephropexien, 11 Ureterolysen, 8 retroperitoneale Lymphadenektomien, 8 Nierenbiopsien, 6 Adrenalektomien, 6 Heminephrektomien, 6 Pyeloplastiken, 5 Ureterolithotomien, 6 Ureterocutaneostomien sowie 2 andere. 38 Patienten (19 %) waren bereits abdominell , 22 (11 %) an Niere und Ureter voroperiert. Die Praparation des Retroperitonealraums erfolgte in 14 Fallen mit Hilfe eines Ballonkatheters, in 93 Fallen mittels eines Ballontrokarsystems, wahrend in den letzten 93 Fallen eine Praparation des Retroperitoneums mit dem Zeigefinger sich als ausreichend erwies. Ergebnisse: Die Eingriffe wurden wie folgt klassifiziert: 76 einfache Operationen (z. B. Nierenbiopsie, Nierencystenresektion, Ureterocutaneostomie), 102 schwierige (z. B. Adrenalektomie, Nephrektomie, Nephropexie) und 22 sehr schwierige Eingriffe (z. B. Pyeloplastik, Heminephrektomie, Lymphadenektomie). Wahrend der ersten 50 Falle zeigte sich eine signifikante Lernkurve, welche sich in einer hoheren Operationszeit und Komplikations- sowie Konversionsrate widerspiegelte. Abhangig vom Schwierigkeitsgrad des Eingriffs betrugen die mittlere Operationszeiten 45–100 min bei leichten Eingriffen, 95–185 min bei schwierigen und 185–240 min bei sehr schwierigen Operationen. In den letzten 50 Fallen war die Komplikations-, Konversions- sowie Reinterventionsrate mit offenen Eingriffen vergleichbar (2, 4 und 2 %). Schlusfolgerung: Nach mehr als 200 retroperitoneoskopischen Eingriffen wurde die Zugangstechnik bedeutend vereinfacht, so das das Verfahren heute standardisiert, sicher und reproduzierbar ist.

Purpose: We describe our experience with laparoscopic retroperitoneal lymph node dissection in 26 patients with nonseminomatous germ cell tumors: 17 had stage I disease with no clinical (computerized tomography, ultrasound or tumor markers) evidence of metastases and 9 (2 with stage IIb and 7 with stage IIc disease) had residual tumor after chemotherapy but with negative tumor markers. Laparoscopic dissection was performed to assess more fully pathological status of the relevant retroperitoneal lymph nodes in both groups.Materials and Methods: The patient was positioned and trocars were introduced at sites similar to that used for transperitoneal laparoscopic nephrectomy (flank position with 3, 10 mm. and 2, 5 mm. ports). After the white line of Toldt was incised and the colon was reflected anteromedially, the retroperitoneal space was exposed. The landmarks of lymph node dissection were then isolated, including the ureter, aorta, inferior vena cava and both renal veins. Lymph node dissection was ...

Many magnetic confinement machines use active feedback stabilization with magnetic actuators. We present a novel magnetic actuators system with a response time much faster than previous ones, making it capable of coping with the fast plasma instabilities. The system achieved a response time of 3 μs with maximal current of 500 A in a coil with inductance of 5.2 μH. The system is based on commercial solid-state switches and FPGA state machine, making it easily scalable to higher currents or higher inductivity.

Solid-state silicon switches are cheap and reliable option for 1–10 MHz RF power sources, required for plasma ion cyclotron RF heating (ICRF). The large `on' resistance of MOSFET and similar devices limits their power delivery to a few tens of kW per switch. Low resistivity devices, such as IGBT, suffer from large `off' switching time, which limits their useful frequency range and increases the power dissipated in the switch. Here we demonstrate more than 0.8 MW circulated RF power at 2 MHz using only three high voltage IGBT switches. The circuit uses the fast `on' switching capability of the IGBTs to generate high-Q pulse train. This operation mode also simplifies the measurement of RF coupling between the antenna and the plasma.

The concept of an intelligent steerable surgical instrument system has been described by various authors. Since 1998, telesurgical minimally invasive procedures have been performed with the da Vinci system, mainly for cardiac bypass surgery. We present our initial experience using the device for robot-assisted laparoscopic radical prostatectomy. The intuitive surgical system consists of two main components: the surgeon's viewing and control console with 3D-imaging, and the surgical arm unit that positions and manoeuvres detachable surgical instruments. These instruments are introduced via two 8 mm trocars and allow movements in all six degrees of freedom (DoF). The surgeon performs the procedure while seated at the console holding specially designed instruments. Highly specialised computer software and mechanics transmit the surgeon's hand movements exactly to the microsurgical movements of the manipulators at the operative site. The system used is a W-shaped five trocar arrangement, with the robot's arms at the lateral trocars (8 mm) and two assistant trocars medially (10 mm). A sixth trocar was used in the right suprapubic area for retraction of the gland (Foley catheter). The left assistant used different instruments, such as bipolar forceps, Ultracision, and Endoclip, wheras the right assistant mainly used the suction#150;irrigation device. The Intuitive System was attached after trocar placement and exposure of Retzius' space. We treated six patients (two pT2, four pT3, median Gleason score 6). The operating room time averaged 315 (range 242#150;480) min, including pelvic lymph-node dissection. No intra-operative complications occured, one patient required transfusions. There were no positive margins, median catheter time was 5 days. Three patients were completely continent after 1 month. Telerobotic laparoscopic radical prostatectomy is feasible. There is a learning curve with the device, mainly due to the magnification, 3D image and lack of tactile feedback. However, the experienced surgeon can become familiar with the device after a short time. There is still a need for further development of instruments for urological procedures.

Telepresence surgery offers theoretically to overcome two main problems of laparoscopic surgery, i.e. the limitation to only four degrees of freedom and the lack of stereovision. Since 1998, telesurgical minimally invasive procedures have been performed with the da Vinci system mainly for cardiac bypass surgery. Clinical experience in urology is still very limited. We want to present our initial experience using the device for robot-assisted laparoscopic radical prostatectomy.The Intuitive surgical system consists of two main components: the surgeon's viewing and control console with 3D imaging and the surgical arm unit that positions and maneuvers detachable surgical instruments. These instruments introduced via two 8-mm trocars allow movements in all 6 degrees of freedom due to the EndoWrist technology. The surgeon performs the procedure seated at the console holding specially designed instruments. Highly specialized computer software and mechanics transfer the surgeon's hand movements exactly to the microsurgical movements of the manipulators at the operative site. We have used a semilunar-shaped 5-trocar arrangement with the robot's arms at the lateral trocars and two assistant trocars medially. A sixth trocar was used in the right suprapubic area for retraction of the gland. The left assistant used different instruments such as bipolar forceps, Ultracision, Endoclip, whereas the right assistant mainly used the suction-irrigation device. Except the first case, the Intuitive System was attached after exposure of Retzius' space.We have treated 6 patients (2 pT2, 4 pT3, median Gleason score 6). The OR time averaged 315 (242-480) min including pelvic lymph node dissection. No intraoperative complications occurred, 1 patient required transfusions. There were no positive margins, median catheter time was 5 days. 3 patients were completely continent after 1 month.Telerobotic laparoscopic surgery offers several advantages over all presently available techniques, such as all six degrees of freedom, dexterity enhancement, tremor filtering, and stereovision. There is a learning curve with the device, mainly because of the magnification, the 3D image and the lack of tactile feedback. However, only after a short period of time, the experienced surgeon is able to get familiar with the device. However, there are still concerns with respect to the high investment and running costs of the device as well as regarding the necessity of further developments of instruments for urological procedures.

In 1999, Guillonneau and Vallancien presented a refined approach of a descending laparoscopic radical prostatectomy which based mainly on the primary access to the seminal vesicles and an improved suturing and knotting technique. Based on our own experience reconstructive laparoscopy as well as with open retropubic radical prostatectomy we have used a combined ascending/descending technique similar to open surgery. In this paper we want to describe our approach and to present the initial results with the Heilbronn technique.A transperitoneal approach is used with a W-shaped arrangement of the trocars (13-mm umbilical port, 2 x 10 mm medial, 2 x 5 mm lateral ports). After the exposure of the Retzius' space and control of the dorsal vein complex the urethra is incised and the distal pedicles of the prostate (+/- the neurovascular bundle) are transsected. We now pull the apex ventrally and start with the incision at the bladder neck followed by a transvesical access to both vasa deferentia and seminal vesicles. The gland is entrapped in the Extraction Bag. After accomplishing the posterior wall of the urethrovesical anastomosis with five interrupted sutures, the foley catheter is placed into the bladder and the bladder neck is closed. Now the prostate is extracted via the umbilical incision. From March 1999 to June 2000, we have performed 100 cases (48 pT2-, 47 pT3- and 5 pT4 tumors). The mean preoperative PSA was 26.8 (1.4-75.5) ng/ml. Two tumors were grade 1, 72 grade 2 and 26 grade 3. Median Gleason score was 6 (3-9). All specimen were inked and examined according to the Stanford protocol. Postoperative continence was evaluated using a questionnaire monitored by a colleague who was involved in surgery.We had 5 conversions (rectal injury, difficult dissection, adhesion, 2x bleeding at the dorsal vein complex). The mean operating time was 278 (180-500) min., the transfusion rate 31%. One patient required reintervention due to bleeding from the right obturator fossa. 95% of the patients did not require any analgesia on the second postoperative day. Positive margins were found in 17% of the patients, of which 12 had a PSA nadir to a value of less than 0.1 ng/ml within 3 weeks after surgery. In 82 patients, the anastomosis was tight after removal of the catheter, median catheter time was 8 (6-30) days. 4% developed a stricture at the anastomotic site which could be treated by laser incision. On discharge 33% were continent, after 6 months 81%, whereas only 2 patients still suffer from grade II stress incontinence at 9 months.Laparoscopic radical prostatectomy is feasible but requires laparoscopic expertise. Its learning curve is still ongoing. Morbidity is low, oncological control is similar to results of open surgery, functional results are promising.

Thin-section spiral computed tomography was used to acquire the volume data sets of the thorax. The tracheobronchial system and pathological changes of the chest were visualized using a color-coded surface rendering method. The structures of interest were then superimposed on a volume rendering of the other thoracic structures, thus producing a hybrid rendering. The hybrid rendering technique exploit the advantages of both rendering methods and enable virtual bronchoscopic examinations using different representation models. Virtual bronchoscopic examinations with a transparent color-coded shaded-surface model enables the simultaneous visualization of both the airways and the adjacent structures behind of the tracheobronchial wall and therefore, offers a practical alternative to fiberoptic bronchoscopy. Hybrid rendering and virtual endoscopy obviate the need for time consuming detailed analysis and presentation of axial source images.

The aim of this prospective study was to assess the diagnostic value of the imaging modalities (chest radiography, spiral computed tomography (SCT) and high-resolution computed tomography (HRCT)) and the tumour markers (carcinoembryonic antigen (CEA), cytokeratin marker (CYFRA 21-1) and neuron-specific enolase (NSE)) in the differentiation of malignant (MSPLs) from benign solitary pulmonary lesions (BSPLs).Solitary pulmonary lesions (SPLs) were examined, evaluated and then completely removed by surgery in 104 consecutive patients (MSPLs n = 81, BSPLs n = 23). Chest radiography was performed with frontal and lateral views, SCT was carried out with a slice thickness of 8 mm and HRCT with a slice thickness of 1 mm and a 12-cm field of view. For the tumour marker analysis, serum concentrations were determined 1-3 days prior to surgery by ELISA for CEA and CYFRA 21-1 and by IRMA for NSE using commercially available assay kits. The cut-off values were set at 3 ng/ml (for non-smokers) and 5 ng/ml (for smokers) for CEA, at 3.3 ng/ml for CYFRA 21-1 and at 12.5 ng/ml for NSE.Using any one of the characteristics with a significance level of P0.01, the identification of MSPLs using chest radiography showed a sensitivity of 64.2% and a specificity of 82.6%, using SCT a sensitivity of 88.9% and a specificity of 60.9% and using HRCT a sensitivity of 91.4% and a specificity of 56.5%. For the identification of MSPLs using CEA a sensitivity of 27.2% and a specificity of 87.0% (accuracy of 40.4%) was observed. Using CYFRA 21-1 a sensitivity of 19.8% and a specificity of 100.0% (accuracy of 37.5%) and using NSE a sensitivity of 13.6% and a specificity of 100. 0% (accuracy of 32.7%) was found.Using chest radiography, SCT and HRCT, a precise morphological assessment of the periphery of the pulmonary lesion and the adjacent visceral pleura is necessary to distinguish MSPLs from BSPLs. Tumour markers used alone or in combination with the imaging methods brought no additional benefits, in terms of sensitivity and accuracy, over the diagnostic imaging methods alone. However, the tumour markers exhibited a far superior specificity (100% for CYFRA 21-1 and NSE) compared with the imaging methods.

The Internet is a fast growing medium, which is about to alter our all day life. Most impact is given to advantages of telemedicine to psychiatrists and psychotherapists as well as patients. After introduction of the essential features of the Internet practical aspects of medicine in Cyberspace for psychotherapists, psychiatrists and their patients are shown. Then, the general prohibition of advertisement for physicians is discussed on the bases of actual laws related to Internet activities. Relevant resources of medical information are shown with regard to the detailed facilities of using search engines. Highlighting opportunities and possible resources of medicine in cyberspace, it is made clear, that the rising interest in telemedicine on Internet is more than justified. Finally, some risks of virtual communication are visible. Important and mentioned Web-sites are listed at the end.

First of all, an introduction to worldwide communication networks is given. Some relevant basic features are explained. Actual and future aspects of the Internet for psychiatry, psychotherapy, and psychosomatic medicine are highlighted. There is a variety of possible advantages in World Wide Web telemedicine for patients, clients, consultants, clinicians and scientists. Useful tools and established opportunities are discussed and listed as Web-sites. The systematic review gives access to the most important fields of mental health on the Internet. Finally, some of the risks of this kind of communication for therapy and society are visible.

The article is preceded by an introduction to world-wide communication networks. Some important basic features are explained. The major impact is on temporary and future aspects of the Internet for psychiatry. A variety of advantages in World Wide Web telemedicine for patients, clients, psychotherapists, clinicians and scientists are extensively demonstrated. Useful and established possibilities are discussed. Finally, the risks of this kind of communication are shown and listed.

A hybrid rendering method (color-coded 3D shaded-surface and volume display) with the possibility of virtual endoscopy using image data sets from HR-SCT was developed. To show the possible advantages and benefits of the improved rendering algorithm we have specifically highlighted the use in relation to the auditory and vestibular system. Postprocessing image visualization offers improved morphological analysis, and will benefit radiological diagnostics, medical education, surgical planning, surgical training and postoperative assessment.

A retroperitoneal access is commonly used for open urological procedures. Since the introduction of the balloon dissecting technique by Gaur this anatomical route has also been used for laparoscopic surgery. We present our experience with retroperitoneoscopy in 200 cases.From December 1992 to October 1997 a total of 200 retroperitoneoscopic procedures were performed in 197 patients 4 to 82 years old, comprising 78 nephrectomies, 50 renal cyst resections, 14 nephropexies, 11 ureterolyses, 8 retroperitoneal lymph node dissections, 8 renal biopsies, 6 adrenalectomies, 6 heminephrectomies, 6 pyeloplasties, 5 ureterolithotomies, 6 ureterocutaneostomies and 2 others. Of the patients 38 (19%) and 22 (11%) had undergone previous abdominal surgery, and kidney and ureter operations, respectively. Dissection of the retroperitoneal space was enabled by the use of a balloon catheter in 14, balloon trocar system in 93 and finger dissection technique in 93 cases.We classified 76 procedures (38%) as simple (renal biopsy, renal cyst resections, ureterocutaneostomy), 102 (51%) as difficult (adrenalectomy, nephrectomy, nephropexy) and 22 (11%) as very difficult (pyeloplasty, heminephrectomy, lymphadenectomy). There was a significant learning curve during the first 50 cases reflected by longer operating time, and higher complication, conversion to open surgery and open reintervention rates (14, 10 and 6%, respectively). In addition to the learning curve, mean operating time depended on the difficulty of the procedure, averaging 45 to 100 minutes for a simple, 95 to 185 for a difficult and 185 to 240 for a very difficult retroperitoneoscopy. In the last 50 cases the complication, conversion and reintervention rates (2, 4 and 2%, respectively) were acceptable for routine clinical application.After experience with more than 200 cases of retroperitoneoscopy the access technique has been significantly simplified. The procedure is standardized, safe and reproducible.

In this report we consider the development of the Internet, from its origins as a military invention in the times of the cold war to its present day role, together with the World Wide Web, as a means of global communication which plays a key role in medical research and particularly in medical genetics. A few of the major genetics related research projects and gene research centers are introduced and their aims are briefly discussed. Detailed information about chromosome and gene mapping, together with sequence and structure databases, can be easily and rapidly accessed through the Internet. A variety of web-sites are briefly described and then listed at the end of the report, which will serve as a useful starting point from which the interested reader can access an almost endless source of genetics related information on the Internet. Finally, some of the ethical, legal and social implications of the links between gene therapy and the Intemet are considered.

A retroperitoneal access is most commonly applied for open procedures in urology. With introduction of the balloon dissecting technique, this anatomical route could also be used for laparoscopic surgery.From 12/1992 to 10/1997, a total of 200 retroperitoneoscopic procedures have been performed in 197 patients (age 4-82 years): 78 nephrectomies, 50 renal cyst resections, 14 nephropexies, 11 ureterolyses, 8 retroperitoneal lymph-node dissections, 8 renal biopsies, 6 adrenalectomies, 6 heminephrectomies, 6 pyeloplasties, 5 ureterolithotomies, 6 ureterocutaneostomies and 2 others. Thirty-eight patients (19%) had undergone previous abdominal surgery; 22 (11%) had had kidney and ureter operations. Dissection of the retroperitoneal space was done with a balloon catheter in 14 or a balloon trocar system in 93 cases, and in the last 93 patients digital dissection with the index finger proved to be sufficient.We classified 76 as simple (i.e., renal biopsy, renal cyst resections, ureterocutaneostomy) and 102 as difficult (i.e. adrenalectomy, nephrectomy, nephropexy) and 22 (11%) as very difficult operations (i.e., pyeloplasty, heminephrectomy, lymphadenectomy). There has been a significant learning curve during the first 50 cases as reflected by increased operating time and complications and the conversion rate to open surgery. After that, the OR times mainly depended on the difficulty of the procedure, averaging 45-100 min for an easy retroperitoneoscopy, 95-185 min for a difficult and 185-240 min for a very difficult operation. In the last 50 cases, the complications, conversion and reintervention rate have become comparable to open surgery (2, 4 and 2%).After more than 200 cases of retroperitoneoscopy, the access technique has been significantly simplified. The procedure is standardized, safe and reproducible.

We investigated the technical feasibility and clinical results of bone fixation techniques in combination with needle suspension for correction of female stress urinary incontinence. In our experience the screw-like bone anchor, which is drilled into the public tubercle, represents a minimally invasive but very stable and reliable technique. However, the needle suspension fixed to the bone anchor turned out to be critical. Even though the suspension was fixed in the paraurethral tissue with a deep Z-stitch between the bladder neck and the midurethra, the 1-year recurrence rate was 76%. Our data showed that the suspension sutures pull through the paraurethral tissue because there is no paravesical scar formation as in open procedures. Modifications of the suspension technique (four-point suspension, simultaneous laparoscopic or digital dissection of the paravesical space, combination with sling procedures) revealed significantly improved short-term results. Therefore we conclude that after improvement of the suspension technique the bone anchor will represent a valid option for minimally invasive fixation of a bladder neck suspension.

Bei Flupentixol handelt es sich um ein Neuroleptikum aus der Gruppe der Thioxanthene. Gegenwartig findet es Verwendung aufgrund seiner antipsychotischen Effekte. Es finden sich jedoch auch Hinweise fur eine antidepressive Wirkung (Gruber u. Cole 1991). Die orale Darreichungsform von Flupentixol enthalt 45–55% des biologisch aktiven α-cis-Isomers. Die Bioverfugbarkeit beruht zu etwa 55% auf einem sekundaren First-pass-Metabolismus in Darmwand und Leber. Die hochste Plasmakonzentration wird nach etwa 2–8 h erreicht. Die Halbwertszeit betragt zwischen 19 und 39 h (Jorgensen 1980). Die einmalige orale Gabe pro Tage ist ausreichend, da die Plasmaspiegel hierbei nur geringfugige Schwankungen aufzeigen.

Analysis of more than 100 penile revascularizations using the Mannheim modification showed a success rate as high as 82% in properly selected patients. However, the dissection of the epigastric artery requires a relatively large incision, with the risk of postoperative bleeding, pain, and hernia formation. Therefore, we designed a laparoscopic approach for dissection of the epigastric vessels. From January 1995 to October 1996, we performed laparoscopy-assisted penile revascularization in 15 pharmacotesting nonresponders with erectile dysfunction. The first step is dissection of the penile vessels to minimize the occlusion time of the epigastric arteries. Thereafter, the extraperitoneal cavity is exposed using a balloon-trocar system inserted via a 15-mm suprapubic incision. A pneumoextraperitoneum is established, and two further cannulas are inserted (10 mm subumbilical, 5 mm in the lower abdomen contralateral to the desired epigastric artery). The dissection of the epigastric vessels starts caudally at the origin from the external iliac vessels and continues to the periumbilical area. All branches are dissected between clips, keeping the artery and vein together. For extraction of the artery, we insert another 5-mm port through the incision at the penile base. After desufflation of the extraperitoneal space and closure of the trocar wounds, microsurgical penile revascularization is performed using the previously described modification of the Hauri procedure. The mean operating time for laparoscopic dissection of epigastric artery was 120 minutes. No intraoperative complication occurred. One patient suffered from an inguinal hematoma. After a median follow-up of 12 month, 53% of patients showed spontaneous erections, and another 27% achieved a full erection with the aid of additional pharmacotherapy. Laparoscopic dissection of the epigastric arteries proved to be feasible, resulting in a considerable reduction of overall morbidity of penile revascularization without reducing the efficacy of the procedure.

We describe our experience with laparoscopic retroperitoneal lymph node dissection in 26 patients with nonseminomatous germ cell tumors: 17 had stage I disease with no clinical (computerized tomography, ultrasound or tumor markers) evidence of metastases and 9 (2 with stage IIb and 7 with stage IIc disease) had residual tumor after chemotherapy but with negative tumor markers. Laparoscopic dissection was performed to assess more fully pathological status of the relevant retroperitoneal lymph nodes in both groups.The patient was positioned and trocars were introduced at sites similar to that used for transperitoneal laparoscopic nephrectomy (flank position with 3, 10 mm. and 2, 5 mm. ports). After the white line of Toldt was incised and the colon was reflected anteromedially, the retroperitoneal space was exposed. The landmarks of lymph node dissection were then isolated, including the ureter, aorta, inferior vena cava and both renal veins. Lymph node dissection was performed identical to that for open surgery, with a modified template including the paracaval, interaortocaval, upper preaortic and right common iliac nodes for right tumors, and para-aortic and upper preaortic nodes for left tumors. Lymph node chains were retrieved with a small organ bag.The procedure was completed successfully in 16 of 17 patients with stage I disease (mean duration 268 minutes for the left and 312 minutes for the right sides). No intraoperative complications were encountered. One patient had delayed ureteral stenosis requiring operative repair, 1 had a pulmonary embolism with an uneventful outcome and 1 who underwent laparoscopic retroperitoneal lymph node dissection on the right side later had retrograde ejaculation. Embryonal carcinoma was found in 1 of the 17 patients. Average postoperative hospital stay was 4.5 days for patients without complications or conversion to an open procedure. After a median followup of 27 months no patient had regional relapse but 2 had pulmonary metastases that were treated successfully with 3 cycles of platinum based chemotherapy. Laparoscopic dissection was significantly more difficult in patients with stage II tumors after chemotherapy. Only in 2 patients with stage IIb disease was laparoscopic lymphadenectomy successful. In 5 of the 7 patients with stage IIc cancer portions of the dissection had to be done after conversion to an open (conventional) operation via a small incision (suprainguinal or pararectal). In 1 patient the laparoscopic approach was completely abandoned and converted to an open operation via a standard midline incision. In all 9 cases histopathological examination revealed complete necrosis. No patient has evidence of disease.Our preliminary experience suggests that a modified laparoscopic retroperitoneal lymph node dissection is feasible for stage I tumors. However, it cannot be recommended after previous chemotherapy (stages IIb and IIc disease).

We report on our clinical experience with laparoscopic nephrectomy in 35 patients. We have performed a total of 18 transperitoneal laparoscopic nephrectomies (TLN) for benign renal disease. After the introduction of a hydraulic dissecting device, we have since performed 17 retroperitoneal laparoscopic nephrectomies (RLN). These data were compared with those in 19 consecutive open nephrectomies (N). All groups were comparable in terms of indication. The mean operative time for benign disease was 206.5 min for TLN, 211.2 min for RLN and 117 min for N. Analgesic medication requirement per patient was 2 days for TLN, 1 day for RLN and 4 days for N, while the postoperative hospital stay averaged 7 days for TLN, 6 days for RLN and 10 days for N. Our results demonstrate the advantage of a laparoscopic approach over open surgery and also reveal the distinct benefit of a retroperitoneal approach. However, due to the small number of indications this procedure should be restricted to a few urologic centers.

Retroperitoneoscopic procedures were already being performed in the late 1970s. The clinical breakthrough of retroperitoneoscopy, however, was initiated in 1992 by the balloon-dissecting technique of Gaur, together with the experience gained with transperitoneal laparoscopic procedures in the upper retroperitoneum. We have modified the balloon-dissecting technique into a hydraulic video-optically controlled balloon dissection of the retroperitoneal space, and this procedure was recently further simplified. From December 1992 to December 1995 we performed 100 retroperitoneoscopic procedures in 98 patients (aged 4-82 years). Twenty-two patients had undergone previous abdominal surgery, 16 patients had been operated on for kidney and ureter problems. We performed 28 simple procedures (6 renal biopsies, 17 renal cyst resections, 4 ureterocutaneostomies, 1 foreign body retrieval), 65 difficult operations (47 nephrectomies, 5 nephroureterectomies, 5 nephropexies, 4 ureterolithotomies, 2x ureterolysis). There were also 9 complicated cases (5 heminephrectomies, 2 tumor nephrectomies, 2 dismembered pyeloplasties). Operating time, complications and conversion rate to open surgery mainly depended on the difficulty of the procedure and the personal learning curve, resulting in 50-90 min, 0% and 3.8%, respectively, for an easy retroperitoneoscopy, 90-210 min, 12% and 9.2% respectively for a difficult operation, and 180-390 min, 22% and 11%, respectively, for a very difficult procedure. Excluding the 17 patients with complications or conversion (unclear anatomy, extremely difficult dissection), the mean postoperative need for analgesics was 0.7 vials, and the mean hospital stay was 4.7 days. We have now passed most of our learning curve, and retroperitoneoscopy has become a standardized procedure that is a part of the training program for the experienced urologist.

We describe our experience with laparoscopic retroperitoneal lymph node dissection in 19 patients with non-seminomatous germ cell tumors. Twelve patients had stage I disease with no clinical evidence (CT-scan, ultrasound, tumor markers) of metastases; 7 patients (stage IIb=2, stage IIc=5) had residual tumor after chemotherapy but with negative tumor markers. A laparoscopic dissection was used to asses more fully the pathologic status of the relevant retroperitoneal lymph nodes of both groups. The patient was positioned and trocars introduced at sites similar to that used for transperitoneal laparoscopic nephrectomy (flank position, five ports - 3 x 10 mm; 2 x 5 mm). After reflecting the colon anteromedially, the landmarks of the lymph node dissection were isolated-namely the ureter, aorta, inferior vena cava, and both renal veins. The lymph node dissection included the paracaval, interaorto-caval, upper preaortic, and right common iliac zonal nodes for right-sided tumors, and paraaortic, upper preaortic zones for left-sided tumors. Retrieval of the lymph nodal chains was accomplished using a small organ bag. The mean duration of the procedure was 298 (range 150-405) minutes. In only one patient was a lymph node positive for tumor (stage I). Otherwise nodes showed extensive necrosis (after chemotherapy). No intraoperative complications were encountered but three patients developed a delayed complication (ureteral stenosis, pulmonary embolism, and retrograde ejaculation, respectively). Whereas we completed the dissection in each patient with stage I tumors, the laparoscopic procedure was more difficult in patients with stage II tumors after chemotherapy. In two patients with stage IIb disease laparoscopic lymphadenectomy was successful. In four other patients parts of the dissection had to be done after conversion to an open (conventional) operation using a small incision (suprainguinal or pararectal); in one patient the laparoscopic approach was abandoned and converted to an open operation. In the post-chemotherapy group the outcome depended primarily on the tumor bulk prior to drug treatment. In two patients in whom all residual necrotic tissue was removed laparoscopically they had "minor" disease (stage IIb); the others had stage IIc tumors. Our preliminary experience suggests that a modified laparoscopic lymph node dissection is feasible for stage I tumors and in selected patients with marker negative residual tumor after chemotherapy (stage IIb).

A doxorubicin-resistant human bladder carcinoma cell line RT112/D21 was established by continuous exposure of the parental line RT112 to increasing concentrations of doxorubicin over a period of 9 months. RT112/D21 cells expressed significantly more P-170 glycoprotein than the parental line, and rhodamine 123 efflux, as a functional parameter of P-170 glycoprotein activity, was increased. RT112/D21 cells were 96 times more resistant to doxorubicin than RT112 cells, and cross-resistance to epirubicin and vinblastine was present. Sensitivity to methotrexate and mitomycin C remained unchanged. R-verapamil reversed resistance to doxorubicin, epirubicin and vinblastine in RT112/D21 cells but did not affect sensitivity to methotrexate and mitomycin C. In RT112 cells, R-verapamil had no effect on drug sensitivity. Thus, it may be assumed that primary or induced MDR1 gene-encoded P-170 glycoprotein expression is a relevant mechanism of chemoresistance in transitional cell carcinoma, and that chemotherapeutic strategies in combination with chemosensitizers improve response rates.

The control of muscle invasive carcinoma of the urinary bladder remains a challenge for the urological oncologist and the best management is still controversial. The treatment options include radical cystectomy, full-thickness transurethral resection (TUR), radiotherapy and chemotherapy — either alone or in combination with other treatments. Radical cystectomy has become accepted as the “gold-standard” against which other treatments are compared — even though survival rates after cystectomy in any one series can be difficult to compare with others owing to differences in patient selection and recent improvement in anaesthetic techniques.

Various valve mechanisms, customarily employed in continent urinary diversion, were constructed from fresh cadaveric porcine bowel for later urodynamic assessment. A total of six different types of valves were formed from ileum or colon in varying lengths and tested by volume pressure trials. The leak point or maximum pressure were recorded at constant perfusion rates of 30 ml/min of the constructed reservoir. Ileal or colonic nipple valves, as well as the embedded or pulled-through ileum, tapered to 12 F at a length of 3 cm, withstood maximum pressures ranging between 75 and 138 cm H2O before leakage or protrusion of the valve occurred. Plicated or tapered terminal ileum in caecal reservoir revealed water leakage at pressures as low as 25 to 40 cm H2O. A newly-developed valve mechanism consisting of a 12 F, plicated colonic-serosal tunnel with a minimum intra-reservoir length of 5 cm resisted maximum pressures of more than 70 cm H2O. Our cadaveric porcine bowel model proved to be reliable for acute volume/pressure trials and correlated with all clinical urodynamic results and animal trials. It is simple, inexpensive and allows scope for individual ideas before commencing with animal trials.

Extracorporeally-perfused rabbit kidneys were exposed to five shock waves at 14 kV on the XL1 Dornier experimental lithotripter (Dornier Medical Systems, Inc., Germering, Germany). While the perfusion flow rate was kept constant, the arterial perfusion pressure was recorded to assess changes in vascular resistance. Immediately after shock wave application, perfusion pressure decreased by 20%-30%, followed by a short, relative pressure rise that did not reach pretreatment values. Fifteen-twenty minutes later, arterial perfusion pressure reattained pretreatment values. Subsequent to treatment, urine flow decreased by greater than 50%. The observed pressure rise was also induced in nontreated kidneys by perfusion with the effluent of treated kidneys indicating that this is based on a humoral mechanism. On the other hand, shock wave application to formalin fixed kidneys only caused a marked decrease in arterial perfusion pressure, suggesting that this effect is due to a pure mechanical interaction of the shock wave also found with denaturated kidneys. The observed decrease of urine flow is probably caused by a decreased filtration rate. Since this was not the case in nontreated kidneys being perfused with the effluent of treated kidneys, the reduction of urine flow after extracorporeal shock wave lithotripsy does not appear to be mediated by a humoral factor, but is more likely a result of the mechanically-induced vasodilation with consecutive decline of the glomerular filtration rate.

Im Mittelpunkt der Diskussion um die pathophysiologischen Veranderungen, die wahrend einer unilateralen Harnstauung ablaufen, steht die praglomerulare Vasokontriktion. Sie lost etwa 5-6 Stunden nach Induktion der einseitigen Obstruktion die initiale praglomerulare Vasodilatation ab und kann wie Huland und Mitarbeiter zeigen konnten, durch Blockade der Thromboxansynthese blockiert werden.