[Therapy options in lower kidney calix calculus].
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Clinical Trials as Topic↗
Biomedical subjects
K U Köhrmann
Publications and source records attributed to K U Köhrmann.
[Urologic interventional therapy of kidney calculi (II)--Endoscopic methods: ureterorenoscopy and percutaneous nephrolitholapaxy].
Although ESWL allows for the treatment of most urinary stones, there are remaining situations, in which satisfying results cannot be achieved, e.g. large kidney stones or specific anatomy. In such cases endoscopic procedure like ureterorenoscopy (URS) or percutaneous nephrolithotomy (PCNL), alone or in combination with ESWL, allow minimally-invasive removal of these stones. Primarily, the development of modern intracorporeal lithotripter probes and extraction instruments along with a reduction of instruments' diameter could improve efficacy and reduce mortality. This article will provide an overview of techniques, application and results of endoscopic urinary stone treatment.
Combined Modality Therapy↗
[Urologic interventional therapy of kidney calculi (I)--extracorporeal shockwave lithotripsy].
With a prevalence of around 5% in western countries, urolithiasis is a frequently occurring disease but with a poorly understood pathogenesis. Effective prevention is not possible for most stone types, in particular for calcium-containing stones, which occur most frequently. Additionally, after occurrence, patient compliance is often inadequate. Interventional therapy becomes necessary after stone manifestation within the urinary tract. Not all stone compositions respond to a drug treatment. Whereas in the seventies, stone treatment meant open surgery newly developed minimally-invasive procedures have displaced this treatment. The clinical introduction of extracorporal shock wave lithotripsy (ESWL) has played a crucial role in this process. Today, more than 80% of all urinary stones can be treated by modern lithotripters. Combination with other minimally-invasive procedures further improve stone free rate. This article provides an overview of technique, application and results of ESWL treatment.
Humans↗
Rotoresect for bloodless transurethral resection of the prostate: a 4-year follow-up.
OBJECTIVE: To report the results and long-term follow-up of transurethral resection of the prostate (TURP) with a new resection device, the Rotoresect (Karl Storz, Tuttlingen, Germany). PATIENTS AND METHODS: Most endoscopic resection techniques for benign prostatic tissue aim for high ablation rates and minimal bleeding. Available resection electrodes are effective, but cause high blood loss (loop electrode), or less bleeding but poorer ablation rates (electrovaporization). To resolve these conflicts the Rotoresect was developed in 1995; it consists of a specially designed rotating resection electrode, driven by a micromotor, and a high-frequency current to enable simultaneous coagulation, vaporization and mechanical tissue removal during resection. To date, 84 patients with benign prostatic hyperplasia have had their prostate resected with this device (mean prostate size 46.0, sd 18.4 mL) and have been assessed for up to 4 years. RESULTS: During resection there was very little bleeding, with no significant changes in haemoglobin or sodium levels. The mean (sd) duration of catheterization was 1.4 (1.1) days; the urinary peak flow rate was improved from 9.7 (3.2) to 24.2 (8.23) mL/s and the residual urine volume reduced from 187.3 (109.6) to 22.7 (19.5) mL. The International Prostate Symptom Score and quality-of-life index were both improved, from 24.0 (7.5) to 4.1 (2.7), and 4.2 (3.2) to 0.8 (0.9), respectively. Overall the results were stable during the 4 years of follow-up. CONCLUSION: The Rotoresect combines the advantages of standard resection (high ablation rate) by actively rotating the resection electrode, and the haemostatic effect of electrovaporization (minimal blood loss) by simultaneous tissue coagulation and vaporization.
Aged↗
[Long-term follow-up of interstitial laser coagulation in the treatment of benign prostatic hyperplasia].
INTRODUCTION: Besides standard open or transurethreal adenoma resection, less morbid interstitial laser coagulation (ILC) is an alternative therapeutical option that could reduce lower urinary tract symptoms, especially in high-risk patients. Although short-term results indicate effectiveness, reliable long-term statistics are still lacking. Therefore, to assess long-term satisfaction and overall success rate, we re-evaluated patients with a mean follow-up of 7 years after laser treatment. METHODS: A total of 72 patients had been included in our ILC programme between 1993 and 1995. Mean age was 74 years. About 45 % of the patients had since died of other causes. In all, 23 patients were evaluated by telephone questionnaire, International Prostate Symptom Score (IPSS), Quality of Life (QoL), second surgical interventions or medical therapy. Our patient group was treated with interstitial Nd:YAG laser coagulation (mediLas fibertom). A perineal (34 %), transurethral (23 %) or combined (43 %) approach was chosen, depending on the preoperative volume of the prostate (range 40 - 100 ml; mean 59.3 ml). RESULTS: 68.4 % of the patients were satisfied with their current urological situation. Mean IPSS was 8.8 vs. 18.8 preoperatively mean QoL 1.5 vs. 3.3. 15.8 % had undergone conventional transurethral prostatic resection in the interim; one patient uses a urine catheter. 15.8 % receive medical treatment for lower urinary tract symptoms. CONCLUSIONS: Although the results of standard TUR or open surgery imply higher success, the long-term results of ILC demonstrate effectiveness. Further follow-up studies on a larger number of patients are advisable. The low morbidity of ILC makes this procedure an interesting alternative option in the treatment of high risk patients.
Aged↗
[Cystinuria - Cystine Stones: Recommendations for Diagnosis, Therapy and Follow-up].
Cystinuria, an autosomal-recessive disorder, is the cause of 1 - 2 % of all kidney stones observed in adults and about 10 % of those observed in infants. Despite increasing understanding of underlying pathomechanisms, patients still form recurrent stones and have to undergo repeated interventions with increasing risk of renal insufficiency. Dietary and medical metaphylaxis may lower the frequency of recurrent stones but are often not practiced. Regular follow-up examinations and optimal therapy significantly enlarge stone-free intervals. This review offers an overview of the underlying pathogenetic mechanisms as well as guidance for diagnosis, monitoring, metaphylaxis and therapy of cystinuria following the recommendations of the Deutsche Gesellschaft für Urologie (DGU) and the European Association of Urology (EAU).
Adult↗
[Minimally-invasive therapy of urinary stones].
Open surgery was the standard therapy for urinary calculi up to about 30 years ago. This changed upon introduction of extracorporeal shockwave lithotripsy (ESWL) in 1980, a procedure that is now the primary therapy for 70 % of the patients in western countries. Simultaneously, endourological procedures like ureterorenoscopy (URS) and percutaneous nephrolithotripsy (PCNL) have been improved, and now, modern small diameter and highly efficient instruments offer an ideal alternative to shockwave lithotripsy. Today, minimally-invasive stone treatment has replaced open stone surgery almost completely. This article introduces ESWL, URS and PCNL and discusses indications, outcomes and limitations.
Follow-Up Studies↗
[Metachronous testicular tumor of an extragonadal germ cell tumor].
INTRODUCTION: Approximately 5 - 7 % of germ cell tumors are of extragonadal origin. Biology and genetics are unclear, especially when the primary location is in the retroperitoneum. Chemotherapy is the initial treatment of choice for extragonadal germ cell tumors (EGGCTs), followed by surgical resection of the residual tumor mass. A primary testicular tumor must be ruled out by sonographic investigation and biopsy. The rate of metachronous testicular cancer in men with primary EGGCT is largely unknown. CASE REPORT: We present the first patient in the literature who developed a metachronous testicular cancer 10 months after primary occurrence of EGGCT in the retroperitoneum. CONCLUSIONS: This case report emphasizes the importance of follow-up examinations of patients with primary EGGCTs. They should include careful sonographic investigation of the testis in order to detect metachronous testicular cancer early. Suspicious findings require open surgery biopsy. Intraoperative histopathology can be false-negative for cancer detection, as an immunohistochemical examination is not available.
Adult↗
Influence of the bridging effect by sequential laser application on tissue ablation in an ex vivo model, taking organ perfusion into account.
OBJECTIVE: To improve the efficacy of interstitial laser coagulation of tissue by causing a 'bridging' effect, using a sequential multiple-probe procedure on an ex vivo kidney model, as only a limited area of tissue is destroyed with a single probe and the coagulation takes longer when multiple punctures are used. MATERIALS AND METHODS: A laser beam was generated using a Nd:YAG laser and applied to kidney tissue by a diffuser tip (quartz glass cap 2 x 19 mm). For sequential laser application (SLA), three probes were placed through punctures into kidney tissue, at 5 or 10 mm apart. The laser energy was applied in different time-energy combinations through the three probes. The effect of SLA was compared with that from one probe delivering the optimal PowerMode 180 protocol (Dornier, Germering, Germany), which represents the standard energy protocol for the clinical treatment of parenchymal organs using this laser device. An isolated porcine kidney was chosen for laser coagulation under different conditions of perfusion. The ablative efficacy was defined as the volume of necrosis per minute. RESULTS: Applying various time-energy combinations to isolated unperfused porcine kidney caused extensive tissue ablation (5.6 mL). In trials with saline and blood perfusion for improved cooling, the necrotic volume was 2.5 and 3.9 mL, respectively (with no carbonization, 3.2 mL). Compared with a single-probe procedure, the ablation efficacy was 10 times better with SLA coagulation. This improvement was initiated by the bridging effect: coagulation in neighbouring areas affects perfusion and convection to an extent that induces the formation of bridges of necrosis between the probes. CONCLUSION: Tissue ablation is markedly improved by interstitial laser coagulation using a sequential multiple-probe technique.
Animals↗
The URO Mentor: development and evaluation of a new computer-based interactive training system for virtual life-like simulation of diagnostic and therapeutic endourological procedures.
OBJECTIVE: To overcome the current disadvantages of traditional training methods for ureterorenoscopy and percutaneous nephrolitholapaxy, using the URO Mentor (Simbionix, Tel Aviv, Israel) computer-assisted simulator. METHODS: The URO Mentor device for training and quality control in ureterorenoscopy was developed using virtual reality, multimedia technology and intelligent tutoring systems. The central software system features a proprietary visualization engine (the SVE) which allows real-time simulation by offering a high-level object-orientated application program interface (written in C++) available for use with either Microsoft, DirectX 7 or OpenGL as platforms. The SVE includes general procedures to allow two- (2D) and three-dimensional (3D) rendering, collision detection, collision correction, 3D morphing, 2D image manipulation, texture mapping, 'bump' mapping, video texture, X-ray rendering, special effects (blood, smoke, stone fragments and more) and reflections. RESULTS: The system allows a complete training session on a wide range of procedures by offering different types of cases and virtual patients, and features a full representation of the endourological procedures under direct vision and by using interactive fluoroscopy with a contrast agent. The supported tools include: baskets, graspers, intracorporal lithotripters, guidewires, catheters, stents, biopsy and dilatation devices. The endourological procedures that can be performed are lithotripsy, tumour resection, treatment of strictures and obstructions, stent placement and biopsies. CONCLUSION: The URO Mentor introduces a new generation of mannequin equipped with a special haptic device, providing trainees with an unparalleled life-like sensation while training for diagnostic and therapeutic endourological procedures. By bringing key advances into urological simulation (e.g. with the real-time X-ray renderer) and by integrating in a single system both high-quality simulation and learning tools, the URO Mentor provides new perspectives for computer-based urological training systems and methods.
Computer Simulation↗
Technical characterization of an ultrasound source for noninvasive thermoablation by high-intensity focused ultrasound.
OBJECTIVE: To develop a generator for high-intensity focused ultrasound (HIFU, a method of delivering ultrasonic energy with resultant heat and tissue destruction to a tight focus at a selected depth within the body), designed for extracorporeal coupling to allow various parenchymal organs to be treated. MATERIAL AND METHODS: The ultrasound generated by a cylindrical piezo-ceramic element is focused at a depth of 10 cm using a parabolic reflector with a diameter of 10 cm. A diagnostic B-mode ultrasonographic transducer is integrated into the source to allow the focus to be located in the target area. The field distribution of the sound pressure was measured in degassed water using a needle hydrophone. An ultrasound-force balance was used to determine the acoustic power. These measurements allowed the spatially averaged sound intensity to be calculated. The morphology and extent of tissue necrosis induced by HIFU was examined on an ex-vivo kidney model. RESULTS: The two-dimensional field distribution resulted in an approximately ellipsoidal focus of 32 x 4 mm (- 6 dB). The spatially maximum averaged sound intensity was 8591 W/cm2 at an electrical power of 400 W. The lesion caused to the ex-vivo kidney at this maximum generator power with a pulse duration of 2 s was a clearly delineated ellipsoidal coagulation necrosis up to 8.8 x 2.3 mm (length x width) and with central liquefied necrosis of 7.9 x 1.9 mm. CONCLUSION: This newly developed ultrasound generator with a focal length of 10 cm can induce clear necrosis in parenchymal tissue. Because of its specific configuration and the available power range of the ultrasound generator, there is potential for therapeutic noninvasive ablation of tissue deep within a patient's body.
Animals↗
[Control parameters for high-intensity focused ultrasound (HIFU) for tissue ablation in the ex-vivo kidney].
PURPOSE: Therapeutic application of contactless thermoablation by high-intensity focused ultrasound (HIFU) demands precise physical definition of focal size and determination of control parameters. Our objective was to define the focal expansion of a new ultrasound generator and to evaluate the extent of tissue ablation under variable generator parameters in an ex vivo model. MATERIALS AND METHODS: Axial and transversal distribution of ultrasound intensity in the area of the focal point was calculated by needle hydrophone. The extent of tissue necrosis after focused ultrasound was assessed in an ex vivo porcine kidney model applying generator power up to 400 Watt and pulse duration up to 8 s. RESULTS: The measurement of field distribution revealed a physical focal size of 32 x 4 mm. Sharp demarcation between coagulation necrosis and intact tissue was observed in our tissue model. Lesion size was kept under control by variation of both generator power and impulse duration. At a constant impulse duration of 2 s, generator power of 100 W remained below the threshold doses for induction of a reproducible lesion. An increase in power up to 200 W and 400 W, respectively, induced lesions with diameters up to 11.2 x 3 mm. Constant total energy (generator power x impulse duration) led to a larger lesion size under higher generator power. CONCLUSION: It is possible to induce sharply demarcated, reproducible thermonecrosis, which can be regulated by generator power and impulse duration, by means of a cylindrical piezo element with a paraboloid reflector at a focal distance of 10 cm. The variation of generator power was an especially suitable control parameter for the inducement of a defined lesion size.
English Abstract↗
Organ sparing surgery for malignant germ cell tumor of the testis.
PURPOSE: We evaluate the indication, technique and long-term outcome of organ preserving tumor resection rather than standard orchiectomy in 73 patients with bilateral testicular germ cell tumors or tumors of a solitary testicle. MATERIALS AND METHODS: Tumor resection was performed in 73 patients with 52 and 17 metachronous and synchronous bilateral testicular germ cell tumors, respectively, and 4 testicular germ cell tumors of a solitary testicle. Histology of the enucleated germ cell tumor revealed seminoma in 42 (57.5%) patients, embryonal carcinoma in 14 (19.2%), mature teratoma in 11 (15.1%), and mixed and combined germ cell tumors in 6 (8.2%). Mean tumor diameter was 15 mm. (range 5 to 30). Associated testicular intraepithelial neoplasia was diagnosed in 82% of patients who underwent local radiation with 18 Gy. RESULTS: After a median followup of 91 months (range 3 to 191) 72 (98.6%) patients had no evidence of disease and 1 died of systemic tumor progression. No local relapse occurred in 46 patients with associated testicular intraepithelial neoplasia treated with local radiation. However, local recurrence did develop in 4 patients after 3, 6, 12 and 165 months without radiation but all survived after undergoing inguinal orchiectomy. Testosterone levels were normal in 62 (84.9%) patients, hypogonadism developed in 7 (9.6%) and preoperative levels remained low in 4 (5.5%). Of the 10 patients who postponed local radiation for paternity reasons 5 had successfully fathered a child after organ sparing surgery. CONCLUSIONS: After a long-term followup of greater than 7 years organ sparing surgery represents a viable therapeutic approach to bilateral testicular germ cell tumor with an excellent postoperative outcome. Tumor enucleation might be considered a standard approach if the guidelines are respected, including cold ischemia, organ confined tumor less than 20 mm., multiple biopsies of the tumor bed, adjuvant local irradiation postoperatively to avoid local recurrence, close followup and high compliance.
Adult↗
Durability of laser probes in interstitial thermotherapy: investigations on an ex vivo model of effect of carbonization.
BACKGROUND AND PURPOSE: Interstitial laser application is successful for clinical tissue ablation in various organs. One great drawback of this method is the high costs caused by the vulnerability of the probes. Our objective was to investigate whether the prevention of carbonization deposits on laser probes averts reduced transmission after the application of high laser energy. MATERIALS AND METHODS: Interstitial laser probes were used to pierce an in vitro kidney model, and 9900 J of energy (Nd:YAG laser) was applied. The transmission of the laser probe was determined and compared with that of a reference probe. RESULTS: The application of laser energy, up to a total of 49,500 J, did not reduce transmission. The deviation of the transmission comparing working probes and the reference probe was between 2% and 7%. The application of high energy (40 W) over a longer period (>20 seconds) led to carbonization and consequent distinct reduction of transmission. CONCLUSIONS: The durability of laser probes can be prolonged by preventing carbonization. The economic effect achieved is the repeated use of the probes at less expense.
Animals↗
Percutaneous nephrostomy versus ureteral stents for diversion of hydronephrosis caused by stones: a prospective, randomized clinical trial.
PURPOSE: Urinary diversion with percutaneous nephrostomy or ureteral stent is indicated by symptoms, such as persistent colic, high temperature and uremia, of hydronephrosis caused by stones. We evaluate which of these 2 methods is superior concerning the course of procedure, relief of accompanying symptoms and quality of life in regard to patient age and sex. MATERIALS AND METHODS: A total of 40 patients with stone induced hydronephrosis were randomized into either percutaneous nephrostomy or stent insertion groups. These patients were then evaluated by procedure (use of analgesics, x-ray exposure, success of insertion), relief of accompanying symptoms (duration of diversion, intravenous administration of antibiotics for high temperature) and quality of life (questionnaire immediately and 2 to 4 weeks postoperatively). RESULTS: Two comparable groups of patients were formed, with an average age of 55 versus 49 years and a male-to-female ratio of 12:8 versus 9:11 for those who underwent percutaneous nephrostomy versus those who received a stent, respectively. Percutaneous nephrostomy was successfully completed in 100% of patients and stents were successful in 80%, with a 20% conversion to percutaneous nephrostomy. The x-ray exposure was shorter in the percutaneous nephrostomy group (p = 0.052). Administration of analgesics was more frequent in the stent group (p = 0.061). Percutaneous nephrostomy indwelling time was shorter (50% less than 2 weeks) than that of stents (25% less than 2 weeks, p = 0.043). Antibiotics were administered for greater than 5 days in 0% of patients who underwent percutaneous nephrostomy versus 64% in those with stents (p = 0.174). Reduction in quality of life was moderate but more pronounced in patients with stents compared to those who underwent percutaneous nephrostomy, and was more distinct in males and younger patients. The quality of life progressively improved in the course of diversion with percutaneous nephrostomy but deteriorated with stents. CONCLUSIONS: Our results demonstrated that percutaneous nephrostomy is superior to ureteral stents for diversion of hydronephrosis caused by stones, especially in patients with a high temperature, as well as in males and juveniles.
Adult↗
[Interdisciplinary consensus on diagnosis and therapy of testicular tumors. Results of an update conference based on evidence-based medicine. German Testicular Cancer study Group (GTCSG)].
BACKGROUND: An "Interdisciplinary Consensus Statement on the Diagnosis and Therapy of Testicular Tumors" was prepared in 1996 by the "Interdisciplinary Testicular Tumor Working Group" (IAH) with input from representatives from diagnostic and therapeutic disciplines of various working groups of the German Cancer Society (Strahlenther Onkol 1997;173:397-406). In 1998 the IAH met again together with the "Testicular Tumor Working Party" of the Urooncology Working Group (AUO) and formed the "German Testicular Cancer Study Group" (GTCSG). Defined and accepted interdisciplinary standards from the initial meeting were revised based on current scientific developments and clinical results. This cooperating effort increased the quality of the initial recommendations and helped to put the recommendations for diagnosing and treating testicular tumor on a broader scientific basis. METHODS: According to the principles of "evidence-based medicine" (EBM), the Consensus from 1996 was modified, based on the current level of evidence from the published literature. The methodological process and evaluation criteria used were that of the "Cochrane Collaboration". RESULTS: An "Interdisciplinary Update Consensus Statement" summarizes and defines the diagnostic and therapeutic standards according to the current scientific practices in testicular cancer. For 21 separate areas scientifically based decision criteria are suggested. For treatment areas where more than one option exist without a consensus being reached for a preferred strategy, such as in seminoma in clinical Stage I or in non-seminoma Stages CS I or CS IIA/B, all acceptable alternative strategies with their respective advantages and disadvantages are presented. This "Interdisciplinary Update Consensus" was presented at the 24th National Congress of the German Cancer Society on March 21st and subsequently evaluated and approved by the various German scientific medical societies.
Evidence-Based Medicine↗
Expression of MAGE antigens and analysis of the inflammatory T-cell infiltrate in human seminoma.
The MAGE gene family encodes antigens that are recognized by cytotoxic T-cells. The expression of MAGE antigens has been linked to tumor stage, and MAGE peptides are under investigation as possible vaccines. Seminomas are tumors that are typically accompanied by a heavy inflammatory infiltrate, but have not been studied with regard to their MAGE antigen expression and its correlation with the inflammatory infiltrate. We investigated, therefore, MAGE protein expression, the amount of cytotoxic T-cells, clonality of the lymphocytic infiltrate, apoptotic activity and occurrence of necrosis. Specimens of 27 patients with classical seminoma were examined by immunohistochemistry for CD4, CD8, CD56, CD45R0, beta2-microglobulin and HLA-DR. MAGE expression was detected with the monoclonal antibody 57B, reactive with MAGE-1, -3, -4, -6 and -12. Clonality of the inflammatory infiltrate was examined by multiplex polymerase chain reaction (PCR) analysis of the T-cell receptor rearrangement. Apoptotic cells were detected by DNA nick-end labeling of fragmented DNA, and the apoptotic index was determined semi-quantitatively. Expression of 57B was found in 19 (70%) of 27 seminomas. In all cases, more than 70% of T-cells expressed CD45R0. In four cases, a predominant infiltration of CD8-positive cytotoxic T-cells (CD4/CD8 ratio < 1) was present. However, 15 seminomas showed a CD4/CD8 ratio > 1. In all cases, infiltration of CD56-positive natural killer cells was only focal. HLA-DR expression was not detectable in tumor tissue; beta2-microglobulin was only focal in three cases. Analysis of the T-cell clonality revealed a polyclonal population. The apoptotic index was not significantly different in 57B-positive seminomas (4.15%) compared with 57B negative seminomas (3.80%). Also, no correlation between the 57B expression and the occurrence of necrosis was found. MAGE antigens are homogeneously expressed in most seminomas, but their presence does not appear to represent a dominant epitope responsible for the lymphocytic infiltrate.
Adult↗
Update on contact lithotripsy.
Despite the development of extracorporeal shockwave lithotripsy, endoscopic stone removal, with or without intracorporeal lithotripsy, is still an effective minimally invasive alternative for special indications. There is no defined all-purpose lithotripsy procedure for contact lithotripsy. The choice of the lithotripsy procedure for endoscopic stone disintegration depends on a number of different factors, the main one being stone localization. Small calibre, flexible probes (electrohydraulic, pneumatic, laser) are especially appropriate for ureterorenoscopy, but the speed of stone disintegration is a limiting factor. In contrast, large calibre rigid probes (ultrasound) are clearly more effective, but are unsuitable in size for flexible ureterorenoscopy. This indicates that the type and size of the endoscope decisively influences the choice of devices for endoscopic stone disintegration. Additional inhibiting factors are the flexibility or the rigidity of the instrument and the diameter of the working channel. It must be noted that total costs are not only calculated on the purchase of the equipment, but must also cover disposable materials.
Humans↗