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Karl-Dietrich Sievert

Publications and source records attributed to Karl-Dietrich Sievert.

17 recordsLinked to original sources
PubMed2006

Closing the tract of mini-percutaneous nephrolithotomy with gelatine matrix hemostatic sealant can replace nephrostomy tube placement.

OBJECTIVES: To investigate the outcomes using gelatine matrix hemostatic sealant to close the tract after mini-percutaneous nephrolithotomy (mini-PCNL), resulting in a tubeless setting. METHODS: After complete stone removal after mini-PCNL, a double-J ureteral stent was placed in an antegrade manner. After withdrawing the 17F Amplatz sheet from the collecting system under direct vision without irrigation, the urothelium collapsed. While retracting the sheet further, the gelatine matrix hemostatic sealant was injected. The skin incision was closed with glue. An ultrasound examination was performed on the first postoperative day to exclude the presence of urine extravasation. RESULTS: Mini-PCNL was performed in 11 patients, either as a primary, small stone, single-access procedure or as a second-look mini-PCNL because of small residual fragments after extracorporeal shock wave lithotripsy. The time to seal the mini-PCNL tract through the kidney parenchyma was 2 to 5 minutes. The mean operative time was 79 minutes. In the first 5 cases, intravenous urography was performed in addition to ultrasonography and demonstrated an intact collecting system. The subsequent procedures demonstrated similar findings, with the exception of 1 case of temporary paravasation. In all other patients, the catheter was removed on the first postoperative day. Ten of 11 patients had an uneventful follow-up until removal of the double-J catheter. No major complications were observed. CONCLUSIONS: Closing the tract of the mini-PCNL with gelatine matrix hemostatic sealant is a safe and fast alternative and provides the option of discharging the patient in good condition without the commonly used nephrostomy tube.

Adult↗
PubMed2006

Radical cystectomy and orthotopic bladder replacement in females.

INTRODUCTION: More than 15 years ago, several centers started to offer urethra-sparing cystectomy and orthotopic urinary diversion for female patients with bladder malignancies. Several studies have been published, outlining both the anatomical and oncological aspects of such an approach. METHODS: In this contribution, the main aspects regarding the surgical technique of cystectomy and orthotopic urinary diversion in female patients, including technical variations which have been derived over the years, are presented. RESULTS AND CONCLUSION: The video shows a detailed description of the surgical technique, and the main steps of the procedure are demonstrated in schematic drawings as well as in animations to facilitate understanding. Emphasis is given on important anatomical and physiological aspects, which have influenced the current surgical steps. Possible sequelae on oncological and functional outcome, which play an important role in the evaluation of this procedure, are also discussed.

Cystectomy↗
PubMed2006

Investigations of urothelial cells seeded on commercially available small intestine submucosa.

OBJECTIVES: To examine adherence and viability of human urothelial cells seeded on commercially available small intestine submucosa (SIS) specimens under serum-free conditions. MATERIALS AND METHODS: Before seeding, SIS was either washed with incubation medium or coated with collagen A, fibronectin, or pronectin. A possible influence of SIS itself on the viability of urothelial cells was analysed with conditioned cell culture medium obtained by incubation of SIS for 24hours. In addition, untreated SIS and a setting without SIS were used as controls. Viability of urothelial cells was analysed with the WST-1 assay until day 9. Histology of seeded and unseeded SIS specimens was investigated after Papanicolaou staining. To demonstrate urothelial cell adherence on SIS, immunohistology was performed with a mixture of monoclonal AE1 and AE3 anticytokeratin antibodies. RESULTS: Urothelial cells seeded on SIS revealed no measurable cell viability. SIS-conditioned cell culture medium was cytotoxic for urothelial cells after 24 hours. Histology only demonstrated cell nuclei and no cytoplasm both in seeded and unseeded SIS specimens, thus indicating porcine DNA. Expression of the cell type-specific marker proteins AE1/AE3 could not be demonstrated. CONCLUSION: Since the commercially available SIS specimens used contained porcine DNA residues and demonstrated cytotoxic effects on urothelial cells, SIS is not suitable for in vitro construction of urothelial cell-matrix implants.

Cell Adhesion↗
PubMed2006

Urethrovaginal fistula--a rare complication after the placement of a suburethral sling (IVS).

A sixty-year-old woman with stress urinary incontinence had undergone a placement of an IVS (Tyco Health Care UK) in another hospital in February 2003. Seventeen months after the procedure, she complained about a suppurative discharge from the vagina and a recurrent severe stress urinary incontinence. The gynecological examination revealed an erosion of the sling into the vagina and a large urethrovaginal fistula bordered by granuloma. After removal of the sling, the urethrovaginal fistula was closed using a vaginal flap. A subsequent conservative treatment regime with duloxetine and pelvic floor training improved the stress urinary incontinence to the patient's satisfaction.

Combined Modality Therapy↗
PubMed2006

MRI-guided biopsy of the prostate increases diagnostic performance in men with elevated or increasing PSA levels after previous negative TRUS biopsies.

OBJECTIVES: Repeatedly negative prostate biopsies in individuals with elevated prostate specific antigen (PSA) levels can be frustrating for both the patient and the urologist. This study was performed to investigate if magnetic resonance imaging (MRI)-guided transrectal biopsy increases diagnostic performance in individuals with elevated or increasing PSA levels after previous negative conventional transrectal ultrasound (TRUS)-guided biopsies. METHODS: 27 consecutive men with a PSA >4 ng/ml and/or suspicious finding on digital rectal examination, suspicious MRI findings, and at least one prior negative prostate biopsy were included. Median age was 66 years (mean, 64.5+/-6.8); median PSA was 10.2 ng/ml (mean, 11.3+/-5.5). MRI-guided biopsy was performed with a closed unit at 1.5 Tesla, an MRI-compatible biopsy device, a needle guide, and a titanium double-shoot biopsy gun. RESULTS: Median prostate volume was 37.4 cm3 (mean, 48.4+/-31.5); median volume of tumor suspicious areas on T2w MR images was 0.83 cm3 (mean, 0.99+/-0.78). The mean number of obtained cores per patient was 5.22+/-1.45 (median, 5; range, 2-8). Prostate cancer was detected in 55.5% (15 of 27) of the men. MRI-guided biopsy could be performed without complications in all cases. CONCLUSION: According to our knowledge, this is the largest cohort of consecutive men to be examined by MRI-guided transrectal biopsy of the prostate in this setting. The method is safe, can be useful to select suspicious areas in the prostate, and has the potential to improve cancer detection rate in men with previous negative TRUS-biopsies.

Biopsy↗
PubMed2006

Collagen I:III ratio in canine heterologous bladder acellular matrix grafts.

The objective of this study was to investigate the limitations of a heterologous bladder acellular matrix graft (BAMG) and the influence of the collagen ratio on functional regeneration in a large animal model. Ten female dogs underwent partial cystectomy; eight received BAMG (two homologous; six heterologous) and two partial cystectomy only. A cystometry was performed prior to surgery and 7 months postoperatively when all animals underwent sacral root stimulation. Tissue specimens were studied by histologic and immunohistochemical techniques and for collagen types. At month 7, all animals survived and bladder capacity in the grafted animals was increased. All grafts demonstrated all components of a normal bladder wall. Nerves were seen with the density decreasing with distance from the anastomosis. The BAMG processing and follow-up demonstrated no changes in the homologous tissue, whereas in the heterologous tissue, the amount of collagen changed with the processing during implantation. None of these heterologous specimens demonstrated a similar collagen ratio to the hosts'. The homologous BAMG undergoes more complete regeneration. In the heterologous BAMG, collagen seems not to be replaced. The amounts and ratio of collagen types I and III seem to influence smooth muscle regeneration.

Animals↗
PubMed2006

Size does matter: 1.5 Fr. stone baskets almost double irrigation flow during flexible ureteroscopy compared to 1.9 Fr. stone baskets.

With a new generation of flexible ureterorenoscopes, a new area in stone management is emerging. Limitation of vision with these new instruments is often caused by insufficient irrigation flow, especially when using instruments like stone baskets, resulting from partial obstruction of the working and irrigation channel with these instruments. Empirically, new available smaller stone baskets seem to dramatically improve irrigation and therefore vision in clinical use. The goal of this study was to show objective differences in basket diameters and flow rates in an in vitro setting. Diameters and irrigation flows in flexible ureterorenoscopes depending on different sizes of stone baskets (Fr. 1.5-1.7-1.9-2.2-2.4-3.0) and different deflections were measured. The measured diameter of the baskets varied within the first 20 cm and the true measured size varied from the manufacturer's specified size to a different extent. The new generation of 1.5 and 1.7 Fr. baskets improved irrigation flow, even compared to the smallest commonly used baskets, up to 68%. Interestingly, deflection did not influence irrigation flow. This study confirmed the subjective impression of inadequate description of relevant basket diameters as well as that of a significant improvement of irrigation flow with the newest generation of stone baskets with smaller diameters.

Calibration↗
PubMed2006

Introducing a novel technique to remove accidentally stitched or entrapped urethral catheters after radical prostatectomy.

INTRODUCTION: A crucial step during radical prostatectomy is anastomosing the bladder neck to the urethral stump after specimen removal. For this purpose, a Foley catheter is inserted transurethrally to achieve a patent and watertight anastomosis. The catheter should be removed 6-10 days after the procedure to avoid ascending infection and stricture formation. On occasion, catheter removal is not possible due to fixation by one of the anastomotic sutures. In this case, a longer catheterization period may increase the risk of infection and formation of an anastomotic stricture. MATERIALS AND METHODS: In the present report, we suggest a technique to overcome this problem by using an endoscopic laser dissection of the anastomotic suture. In 2 patients, a 4.8-Fr pediatric ureteroscope was passed through the urethra along the fixated catheter. After carefully inspecting the anastomosis, a laser fiber was brought in direct contact with the responsible suture. RESULTS AND CONCLUSIONS: By activating the laser, the suture was cut immediately, and the catheter could be removed. Both patients showed no signs of anastomotic leakage or stricture on cystography. Fixation of the catheter after radical prostatectomy is a rare, but bothersome complication, which can compromise the functional outcome of the procedure. Using a pediatric ureteroscope and a laser fiber is an elegant, minimally invasive method to solve this problem. It can be easily and safely performed under local anesthesia in an outpatient setting.

Adenocarcinoma↗
PubMed2006

Clinical outcome after cystectomy in patients with lymph node-positive bladder cancer.

Whereas radical cystectomy is the standard of care in high-grade, invasive bladder tumors, the extent of lymphadenectomy and its diagnostic and/or therapeutic potential is controversial. Independent predictors for lymph node involvement are T-stage, histological grading and lymphovascular invasion. Preoperative assessment, including 3D magnetic resonance imaging and sentinel node detection, are promising concepts for the future. The extension of lymphadenectomy is not yet defined, although prospective data regarding the absence of skipped lesions in the case of pelvic lymphadenectomy and the damage of autonomic nerves in the case of extensive lymphadenectomy are arguments for a limited or stepwise approach. Outcome of N1 patients appears to be nearly equivalent to N0 patients in organ-confined tumors, whereas the outcome of N3 patients is poor in all studies presented to date. Therefore, it has been suggested that a meticulous lymphadenectomy in N1 patients, with positive lymph nodes almost exclusively localized within the endopelvic region, has a long-term therapeutic impact in terms of an improvement in the patient's clinical prognosis. For N2 patients, a long-term survival benefit from extensive lymphadenectomy remains to be demonstrated. Recognizing the inevitably poor clinical prognosis in cases with gross nodal involvement (N3), the clinical value of an extended lymph node dissection in these patients is very questionable.

Cystectomy↗
PubMed2005

Expression of the endothelin axis in bladder cancer: relationship to clinicopathologic parameters and long-term survival.

OBJECTIVES: Endothelin-1 (ET-1) and its receptors ET(A)R and ET(B)R, referred to as the Endothelin-axis, play an emerging role in cancer. We examined the ET-axis immunohistochemically in invasive bladder cancer. METHODS: Tumor specimens from 157 patients after cystectomy were stained immunohistochemically for ET-1, ET(A)R and ET(B)R. After semiquantitative analysis the staining results were correlated with clinicopathological parameters and survival rates. RESULTS: Overexpression of ET-1, ET(A)R and ET(B)R was identified in 26.8%, 58.8% and 76.9% of cases, respectively. No association with TNM staging and histologic grading was found. However, patients with ET(B)R expression tended to have organ-confined tumors (p=0.16) and no vascular invasion (p=0.09), the latter being statistically significant in the subgroup of G3 tumors (p=0.02). ET(B)R overexpression was associated with favorable disease-free survival (p=0.04). CONCLUSIONS: The ET-axis is overexpressed in bladder cancer, ET(B)R predominating in this entity and being associated with a more favorable prognosis. Further studies are warranted to elucidate the role of the ET-axis as a molecular target in bladder cancer.

Adult↗
PubMed2005

Neuromodulation.

Explore the source record for details and available documents.

Autonomic Fibers, Preganglionic↗
PubMed2005

Expression of endothelin-1 and endothelin-A and -B receptors in invasive bladder cancer.

Overexpression of endothelin-1, endothelin-A- and endothelin-B-receptors has been shown in various human tumors. To assess the role of the ET-axis in bladder cancer, we analyzed its expression in tumor specimens and bladder cancer cell lines. Samples were obtained by radical cystectomy at two urologic institutions. ET-axis expression was investigated by reverse-transcription polymerase chain reaction (RT-PCR) (n=22) and immunohistochemistry (n=42). Additionally, four bladder cancer cell lines were analyzed. RT-PCR analysis for the ET-axis showed positive signals in the majority of cDNA probes. Signals for endothelin-1 (ET-1), endothelin-A-receptor (ET(A)R) and endothelin-B-receptor (ET(B)R), as identified semiquantitatively and by densitometry, were found in 22, 22 and 15 of 22 cases, respectively. Immunohistochemistry revealed expression of ET-1, ET(A)- and ET(B)-receptor in 18, 29 and 37 of the 42 cases, respectively, whereas normal urothelium was negative. All cell lines expressed ET-1, and all but the RT-112 cell line produced ETAR, whereas no cell line expressed ET(B)R. The identification of the ET-axis at the mRNA and protein level in the majority of bladder tumor samples suggests a role in the carcinogenesis of bladder cancer. Further studies on regulation of the ET-axis and the future use of selective ET(A)-receptor inhibitors for targeted molecular therapy in bladder cancer are in progress.

Adult↗
PubMed2004

The effect of labor and/or ovariectomy on rodent continence mechanism--the neuronal changes.

Many women develop stress urinary incontinence (SUI) after childbirth, but the exact neuronal changes are largely unknown. This study is designed to identify the neuronal changes associated with pregnancy, delivery and ovariectomy. A total of 10 virgin and 48 pregnant rats were used. Cystometry and stress/sneeze tests were performed in the virgin once and the pregnant rats at certain time points. Postpartum the rats were equally grouped as follows: group I: delivery, group II: delivery + ballooning, group III: delivery + ovariectomy, group IV: delivery + ballooning + ovariectomy. Tissues from bladder, bladder neck, and urethra were analyzed by immunostaining for PGP 9.5, CGRP, SP, NPY, VIP, TH, n-NOS. We found complex innervation changes in the different tissue samples. Since the bladder neck and the mid-urethra play an important role in the continence mechanism the neuronal changes in these areas contribute to the observed functional changes.

Animals↗
PubMed2003

Vaginal and penile reconstruction.

PURPOSE OF REVIEW: Reconstructive surgery for patients with genital abnormalities or for patients who require reconstructive efforts is challenging. This review highlights those articles, which are outstanding among all those important papers, which have been published during the last year (2002-2003). RECENT FINDINGS: A greater understanding of embryonal development improves the success of reconstructive surgery. Other factors, such as the patient's sex, influence the surgical technique used and the degree of invasiveness or complexity. In the adult the pressure to shorten hospital stays has played a big part in the continual modification and enhancement of surgical techniques. In addition to modified techniques, new off-the-shelf materials are introduced to the clinic, which seem to have the potential to improve the surgical outcome and shorten hospital stays. SUMMARY: With the continued successful basic anatomy and basic research, reconstructive surgery brings higher success rates. Long-term results are still required to validate the reliability of these new surgical techniques and materials.

Bladder Exstrophy↗
PubMed2002

Homologous acellular matrix graft for vaginal repair in rats: a pilot study for a new reconstructive approach.

The purpose of this paper is to investigate using an acellular matrix graft of vagina (VAMG) or bladder (BAMG) in vaginal reconstruction. In 18 rats, vaginal length was measured and a hysterectomy performed. In three control animals, the vaginal stump was closed. In eight rats, the vagina was augmented with a VAMG; in seven, a BAMG was used. After 2-12 weeks, the animals were sacrificed, the vaginal length was reevaluated, and the vaginas were prepared for histologic evaluation. In the controls, the vagina was markedly shorter postoperatively. In the grafted animals, vaginal length was not significantly less than preoperative values with either matrix. Epithelialization, vascularization, and alpha-actin expression in the grafts were consistently observed. Regeneration appeared to be slightly greater in the organ-specific vagina matrix. With either matrix, however, although the vaginal stump remained open, the grafts lost most of the lumen. Vaginal reconstruction with a vagina acellular matrix graft is technically feasible. If further experiments can address the problem of luminal collapse - with, for instance, tissue expanders in the matrix - this technique may offer an alternative to the complex therapeutic options currently available.

Animals↗
PubMed2002

Physiologic bladder evacuation with selective sacral root stimulation: sinusoidal signal and organ-specific frequency.

In patients with spinal cord injury above S2, who characteristically have both detrusor hyperflexia and sphincteric spasm, sacral anterior root stimulation can evacuate the bladder, but sacral deafferentation is needed to eliminate the hyperreflexia for normal bladder filling. The common stimulation parameters for these patients activate the detrusor and the external urethral sphincter simultaneously (detrusor-sphincter dyssynergia), and the resultant post-stimulus voiding is not physiologic. We sought to determine organ-specific stimulation parameters. In 20 male dogs, the rectangular pulse and sinusoidal signal forms were evaluated with a variety of parameters for stimulation of S2 and S3 anterior roots extra- and intradurally (i.e., stimulation frequency and voltage, uni- versus bilateral electrode placement, and degree of bladder filling). New torpedo-shaped bipolar electrodes were used, adjusted to neural diameter. The best results were recorded with intradural bilateral sinusoidal signal. Sphincteric fatigue was produced by pre-stimulating S2 with 104+/-17 Hz and 0.8+/-0.1 V for 10 to 15 seconds before S3 stimulation. S3 stimulation with 16+/- 2.1 Hz and 0.4+/-0.1 V evoked a detrusor pressure of 28.7+/-3.0 cm H2O above the sphincteric pressure. Selective anterior root stimulation with organ-specific stimulation parameters can effect initial sphincteric fatigue to achieve physiologic voiding.

Animals↗