Risk factors for the formation of a steinstrasse after extracorporeal shock wave lithotripsy: a statistical model

PURPOSE: We studied the various stone, renal and therapy factors that could affect steinstrasse formation after extracorporeal shock wave lithotripsy (ESWL), Dornier Medical Systems Inc., Marietta, Georgia to define the predictive factors for its formation. Thus, steinstrasse could be anticipated and prophylactically avoided. MATERIALS AND METHODS: Between February 1989 and May 1999, 4,634 patients were treated with a Dornier MFL 5000 lithotriptor (Dornier Med Tech, GmbH, Germany). Renal stones were encountered in 3,403 patients and ureteral stones in 1,231. Steinstrasse were recorded in 184 patients, of whom 74 required intervention and formed the "complicated group." All patient data, stone and renal characteristics, and data of ESWL were reviewed. Univariate and multivariate statistical analyses of patients, stones and therapy characteristics in correlation with the incidence of steinstrasse formation were performed to assign the factors that had a significant impact on steinstrasse formation. RESULTS: The overall incidence of steinstrasse was 3.97%. The steinstrasse was in the pelvic ureter in 74% of the cases, lumbar ureter in 21.7% and iliac ureter in 4.3%. Steinstrasse incidence significantly correlated with stone size and site, the power level (kV.) used during therapy and radiological renal features. Steinstrasse was more common with renal stones more than 2 cm. in diameter in a dilated system, especially with the use of high power (greater than 22 kV.) for disintegration. A statistical model was constructed to estimate the risk of steinstrasse formation accurately. CONCLUSIONS: Stone size and site, renal morphology and shock wave energy are the significant predictive factors controlling steinstrasse formation. If a patient has a high probability of steinstrasse formation, close followup with early intervention or prophylactic pre-ESWL ureteral stenting is indicated.     

Ureteroscopy for the treatment of urolithiasis in children

PURPOSE: Ureteroscopy for treating urolithiasis in prepubertal children has become more common with the advent of smaller instruments. We reviewed our experience with ureteroscopy for urolithiasis in this cohort of patients as well as the literature using this treatment modality in children. MATERIALS AND METHODS: Between 1994 and 2000 we performed 27 ureteroscopic stone extractions in 25 children. Ureteroscopy was done in a manner similar to that in adults. Ureteral dilation was performed when necessary to access the ureter. A stent was placed postoperatively if there was significant ureteral trauma. RESULTS: Of the 25 children 13 were male and 12 were female. Average age was 9.2 years (range 3 to 14). Stones were 2 to 12 mm. in greatest diameter (average 6). Of the 27 procedures the ureteral orifice was dilated before stone treatment in 15 (56%), while in 19 (70%) a stent was placed afterward. No intraoperative and 2 postoperative complications were identified. Overall 92% of the children were rendered stone-free after 1 procedure and 100% were stone-free after 2. CONCLUSIONS: Ureteroscopy for urolithiasis in prepubertal children is safe and effective. Routine ureteral dilation and ureteral stent placement are not always necessary in these patients.     

Urinary tract infections: what's new?

PURPOSE: This review provides practicing urologists with important basic information about urinary tract infections (UTIs) that can be applied to everyday clinical problems. MATERIALS AND METHODS: A review is presented of provocative and controversial concepts in the current literature. RESULTS: Bacterial virulence mechanisms are critical for overcoming the normal host defenses. Increasing antimicrobial resistance of uropathogens has led to reconsideration of traditional treatment recommendations in many areas. For effective patient management the first issue is to define complicating urological factors. Managing complicated urinary tract infections, particularly in urology, is determined by clinical experience to define the pertinent anatomy and to determine the optimal interventions. New clinical data are summarized on UTIs in long-term care patients, behavioral risks for UTI in healthy women and anatomical differences associated with an increased risk for UTI. The rationale is presented for UTI prophylaxis using cranberry juice, immunization and bacterial interference. Current treatment trends for UTI include empiric therapy (without urine culture and sensitivity testing), short-course therapy, patient-administered (self-start) therapy and outpatient therapy for uncomplicated pyelonephritis. CONCLUSIONS: Recommendations for treating patients with UTIs have changed based on basic science and clinical experience.     

Long-term followup and outcome of continent catheterizable vesicocstomy using the Rink modification

PURPOSE: Multiple techniques have been described to create a Mitrofanoff channel in the pediatric population. A small subset of patients only requires creation of a catheterizable channel without bladder augmentation. These patients are ideal candidates for a procedure that avoids the use of intestine, especially in the absence of a suitable appendix. We used a modification of the Casale vesicostomy, as described by Rink, to create a continent vesicostomy in these children. We report our long-term experience with this technique. MATERIALS AND METHODS: We retrospectively reviewed the medical records of all patients who underwent continent vesicostomy at our institution between 1992 and 2000. Patient diagnosis, stomal site, associated bladder procedures, stomal continence, followup and complications associated with continent vesicostomy were documented. RESULTS: Of the 31 patients who underwent continent vesicostomy, as described by Rink, 14 were female and 17 were male. Average age was 9 years (range 2.5 to 22). Primary diagnosis included neuropathic bladder in 15 cases, the prune-belly syndrome in 6, cloacal exstrophy/anomaly in 5 and other in 5. The stoma was placed in the lower abdomen in 17 patients, in the umbilicus in 7 and in a neoumbilicus in 7. Simultaneous procedures included ureteral reimplantation in 8 cases, bladder augmentation in 5, bladder neck surgery in 4 and reduction cystoplasty in 2. Mean followup was 41 months. All patients achieved excellent stomal continence. Complications included stomal stenosis requiring revision in 14 cases (45%). Stenosis developed in 60% of the patients with neuropathic bladder and in 86% with an umbilical stoma. Eventually 6 patients underwent conversion to an alternative catheterizable channel. CONCLUSIONS: Continent vesicostomy can be performed successfully when there is any underlying bladder pathology with 100% stomal continence. Despite the higher rate of stomal problems with this type of Mitrofanoff channel we think that continent vesicostomy is a reasonable alternative in patients with a large bladder requiring only catheterizable channel creation. Because of the excellent results reported with the Monti-Yang technique, we would currently recommend this procedure over continent vesicostomy when bowel is used for bladder reconstruction.     

Effect of spinal cord abnormalities on the function of the lower urinary tract in patients with anorectal abnormalities

PURPOSE: We evaluated the effect of spinal cord abnormalities on lower urinary tract function in patients with anorectal abnormalities. MATERIALS AND METHODS: We examined 30 patients with anorectal anomalies mainly because of fecal or urinary incontinence. All patients underwent spinal magnetic resonance imaging and urodynamic investigation. RESULTS: Major lumbosacral abnormalities were detected in 57% of patients, including 13, 4 and 3 with a tethered cord, syringomyelia and caudal regression, respectively. Significant dysfunction of the lower urinary tract in 57% of the cases involved an overactive detrusor in 11, detrusor-sphincter dyssynergia in 4, distended bladder in 4 and lazy bladder in 1. When the spinal cord was normal, 54% of the patients had abnormal urodynamic findings but when the spinal cord was abnormal, 59% had abnormal urodynamics. When the bony spine was normal, 33% of the patients had an abnormal spinal cord but when the bony spine was abnormal, 69% had an abnormal spinal cord. CONCLUSIONS: Patients with anorectal abnormalities and fecal or urinary incontinence problems often have an abnormal spinal cord and abnormal urodynamic findings. However, the state of the spinal cord is not the only factor explaining lower urinary tract function. Thus, the possibility of lower urinary tract dysfunction should be considered in each patient with anorectal abnormalities. If the patient has symptoms or findings suggesting abnormal lower urinary tract function urodynamic evaluation should be performed.     

Transcorporal artificial urinary sphincter cuff placement in cases requiring revision for erosion and urethral atrophy

PURPOSE: A distal cuff location is often required in patients undergoing artificial urinary sphincter reimplantation after previous erosion or in those requiring revision because of urethral atrophy at the original cuff site. Dissecting the urethra at a more distal site increases the risk of urethral injury and erosion, and often the urethral circumference is so small that a 4 cm. cuff is too large. We present a novel technique for distal cuff placement using transcorporal dissection that leaves corporal tunica albuginea on the dorsal surface of the urethra, allowing for its safer mobilization and adding to its bulk. MATERIALS AND METHODS: We reviewed the charts of 31 men who underwent this technique and contacted 26 by telephone. The indications for distal transcorporal cuff placement varied. In 7 men with inadequate urethral coaptation with a 4 cm. proximal cuff at initial implantation a primary transcorporal tandem cuff was implanted distal. In 8 men persistent or recurrent incontinence despite a 4 cm. proximal cuff led to secondary distal reimplantation. Previous artificial urinary sphincter erosion and/or infection in 10 cases, previous urethral surgery at the optimal cuff site in 5 and radiation changes at the optimal cuff site in 1 led to selection of the more distal site and technique. Of the transcorporally placed cuffs 18 were 4 cm. and 13 were 4.5 cm. Preoperatively 5.2 pads were used daily. Of the 31 patients 27 were impotent preoperatively, 1 had normal erections, 1 had partial erections with the MUSE drug delivery system (Vivus, Inc., Menlo Park, California) and 2 had a previously placed penile prosthesis. RESULTS: At a mean followup of 17 months 26 of the 31 patients (84%) had occasional or no stress incontinence requiring 0 to 1 pad daily, 2 with pure urge incontinence used 1 to 2 pads daily and 3 had mixed incontinence requiring 0 to 3 pads daily. Of the 26 men surveyed 25 were very satisfied with the postoperative level of incontinence. Postoperatively erectile function deteriorated in 1 patient and was unchanged in the remainder. There was no erosion or infection of the transcorporally placed cuffs, although 3 were replaced for malfunction. CONCLUSIONS: This technique offers significant advantages in cases of revision. The technique protects the urethra from intraoperative dissection injury and decreases the risk of erosion because the urethra is buttressed at its vulnerable location. In addition, bulk is added to the urethra, allowing for better cuff sizing, which is usually a problem at this location where the urethra is small, thereby, improving continence in revised cases. Our success has recently led us to abandon tandem cuff placement altogether. There is a potential for deteriorating erectile function in potent men who undergo implantation in this fashion.     

Removal of transurethral catheter during urodynamics may unmask stress urinary incontinence

PURPOSE: The measurement of Valsalva leak point pressure may have an important role in the treatment algorithm of women with stress urinary incontinence. However, some patients with stress urinary incontinence may not have leakage during standard urodynamic studies and, thus, the Valsalva leak point pressure cannot be determined. We hypothesized that the transurethral catheter may inhibit leakage during urodynamics. MATERIALS AND METHODS: We evaluated 21 consecutive women presenting with complaints of stress urinary incontinence who failed to have leakage on urodynamic studies. Bedside cystometry was performed, followed by urodynamics using a 6Fr transurethral catheter. When stress urinary incontinence was not noted, the catheter was removed and the Valsalva leak point pressure was measured using the intraabdominal pressure catheter. RESULTS: No woman had leakage on urodynamic studies with the catheter in place, although 11 of 21 had leakage after the catheter was removed and 15 had leakage on bedside cystometry. All 11 patients with leakage at catheter removal showed leakage on bedside stress testing. Mean Valsalva leak point pressure in those with leakage was 67 cm. water. CONCLUSIONS: Patients with a history of stress urinary incontinence and those with a positive bedside stress test who do not have leakage during a Valsalva maneuver on urodynamic studies should repeat the Valsalva maneuver with the catheter out. This technique may unmask stress urinary incontinence and allow the measurement of Valsalva leak point pressure.     

Predicting urinary stone composition using X-ray coherent scatter: a novel technique with potential clinical applications

PURPOSE: Coherent scatter properties depend on the molecular structure of the scattering medium and measured scatter patterns are often characteristic of a chemical species. We explored the usefulness of coherent scatter analysis as a basis for identifying urinary calculus composition. MATERIALS AND METHODS: A laboratory system for collecting coherent scatter signals from biological specimens was developed. This technique uses a diagnostic x-ray tube and image intensifier, and measures coherent scatter from intact renal stones. The coherent scatter signatures of 6 common stone components (calcium oxalate monohydrate, calcium phosphate, calcium phosphate dihydrate, cystine, magnesium ammonium phosphate and uric acid) were acquired from pure chemical samples and stones identified by infrared spectroscopy as having a uniform composition. In addition, a sample of calculus identified as containing only calcium oxalate dihydrate was examined. The same fragmented stone samples analyzed by infrared spectroscopy were scanned using coherent scatter. RESULTS: In each case the scatter patterns from powdered chemicals and fragmented stones showed circular symmetry and consisted of a series of broad rings of various intensities. Each pure chemical sample produced a distinct coherent scatter pattern. The signatures of the stone specimens closely agreed with those of the chemical samples. CONCLUSIONS: These initial results indicate that coherent scatter analysis using diagnostic x-rays has potential as a tool for urinary calculous composition identification. Further developments in this technique may have the potential for determining the composition of a calculus in vivo before therapy, thus, aiding in therapy planning.