Recent advances in lithotripsy technology and treatment strategies: A systematic review update.

INTRODUCTION: Shock wave lithotripsy (SWL) is a well - established treatment option for urolithiasis. The technology of SWL has undergone significant changes in an attempt to better optimize the results while reducing failure rates. There are some important limitations that restrict the use of SWL. In this review, we aim to place these advantages and limitations in perspective, assess the current role of SWL, and discuss recent advances in lithotripsy technology and treatment strategies. METHODS: A comprehensive review was conducted to identify studies reporting outcomes on ESWL. We searched for literature (PubMed, Embase, Medline) that focused on the physics of shock waves, theories of stone disintegration, and studies on optimising shock wave application. Relevant articles in English published since 1980 were selected for inclusion. RESULTS: Efficacy has been shown to vary between lithotripters. To maximize stone fragmentation and reduce failure rates, many factors can be optimized. Factors to consider in proper patient selection include skin - to - stone distance and stone size. Careful attention to the rate of shock wave administration, proper coupling of the treatment head to the patient have important influences on the success of lithotripsy. CONCLUSION: Proper selection of patients who are expected to respond well to SWL, as well as attention to the technical aspects of the procedure are the keys to SWL success. Studies aiming to determine the mechanisms of shock wave action in stone breakage have begun to suggest new treatment strategies to improve success rates and safety.

Renal crystal deposits and histopathology in patients with cystine stones.

We have biopsied the papillae of patients who have cystine stones asking if this stone type is associated with specific tissue changes. We studied seven cystine stone formers (SF) treated with percutaneous nephrolithotomy using digital video imaging of renal papillae for mapping and obtained papillary biopsies. Biopsies were analyzed by routine light and electron microscopy, infrared spectroscopy, electron diffraction, and micro-CT. Many ducts of Bellini (BD) had an enlarged ostium, and all such were plugged with cystine crystals, and had injured or absent lining cells with a surrounding interstitium that was inflamed to fibrotic. Crystal plugs often projected into the urinary space. Many inner medullary collecting ducts (IMCD) were dilated with or without crystal plugging. Apatite crystals were identified in the lumens of loops of Henle and IMCD. Abundance of interstitial Randall's plaque was equivalent in amount to that of non-SF. In the cortex, glomerular obsolescence and interstitial fibrosis exceeded normal. Cystine crystallizes in BD with the probable result of cell injury, interstitial reaction, nephron obstruction, and with the potential of inducing cortical change and loss of IMCD tubular fluid pH regulation, resulting in apatite formation. The pattern of IMCD dilation, and loss of medullary structures is most compatible with such obstruction, either from BD lumen plugs or urinary tract obstruction from stones themselves.

Laparoscopic transverse hemicystectomy with ileocystoplasty in a porcine model.

BACKGROUND AND PURPOSE: The ideal replacement for bladder tissue is yet to be described, although multiple alternatives have been studied. Currently, enterocystoplasty, despite its limitations, is considered the gold standard for bladder augmentation. This study evaluated the feasibility, safety, and morbidity of laparoscopic ileocystoplasty in a large-animal model. MATERIALS AND METHODS: In eight minipigs, laparoscopy was performed using four ports. A segment of ileum was delivered through a 3-cm umbilical incision and detubularized and refashioned using standard open surgical technique. Laparoscopic hemicystectomy was then performed, followed by laparoscopic suturing of the ileal patch to the bladder. The bladder was drained with a Foley catheter, but no pelvic drain was placed. All animals were followed for for a minimum of 3 months. Preoperative and postoperative evaluation included measurement of bladder capacity, ultrasound imaging of the kidneys, blood counts, and serum electrolyte and creatinine measurements. Two of the animals were sacrificed at 3 months and one at 6 months, and the bladders were harvested. RESULTS: Eight animals underwent ileocystoplasty without intraoperative or postoperative complications. The average operating and anastomosis time was 250 minutes and 96 minutes, respectively. All animals had normal preoperative blood values that remained normal during follow-up. Bladder capacity decreased initially to 71% of the baseline volume and then increased to 83% and 117% at 3 and 6 months. One of three animals sacrificed was noted to have a right midureteral stricture. CONCLUSIONS: We developed a reliable laparoscopic technique for ileocystoplasty that may extend the advantages of laparoscopy, including better cosmesis and reduced risk of postoperative adhesions, to bladder augmentation.

Holmium laser enucleation for prostate adenoma greater than 100 gm.: comparison to open prostatectomy.

PURPOSE: Options for treatment of large (greater than 100 gm.) prostatic adenomas have until now been limited to open surgery or transurethral resection by skilled resectionists. Considerable blood loss, morbidity, extended hospital stay and prolonged recovery occur with open surgery for large prostatic adenomas. Endoscopic surgery for benign prostatic hyperplasia has evolved during the last decade to offer the patient and surgeon significant advantages of transurethral removal of prostatic adenomas. Holmium laser enucleation of the prostate with transurethral tissue morcellation provides significant reductions in morbidity, bleeding and hospital stay for patients with large prostate adenomas. MATERIALS AND METHODS: A retrospective review of data on 10 cases of holmium laser enucleation and 10 open prostatectomies for greater than 100 gm. prostatic adenomas was performed from 1998 to 1999 at our institution. Patient demographics, indication for surgery, preoperative and postoperative American Urological Association (AUA) symptom scores, operating time, serum hemoglobin, resected prostatic weight, pathological diagnosis, length of stay and complications were compared. RESULTS: Patient age, indications for surgery (retention, failed medical therapy, high post-void residual, bladder calculi, bladder diverticula and azotemia) and preoperative AUA symptom scores were similar in both groups. Postoperative AUA symptom scores were significantly decreased (p <0.004) in both groups. Operating times were not significantly different. Serum sodium was unchanged by holmium laser enucleation (not significant), and postoperative hemoglobin was not significantly reduced in the holmium laser enucleation group but decreased significantly in the open prostatectomy group (mean decrease 2.9 +/- 0.7 gm., p = 0.0003). Resected weight was greater in the holmium laser enucleation group (151 versus 106 gm., p = 0.07). Length of stay was significantly shorter in the holmium laser enucleation group (2.1 versus 6.1 days, p <0.001). Complications in the holmium laser enucleation group included stress urinary incontinence in 4 cases, prostatic perforation in 1 and urinary retention in 1. No patient treated with holmium laser enucleation was discharged home with an indwelling catheter. Complications in the open prostatectomy group included bladder neck contractures in 2 cases, stress incontinence in 1 and urge incontinence in 1. All patients treated with open prostatectomy were discharged home with an indwelling catheter. CONCLUSIONS: Holmium laser enucleation is an effective, safe procedure for large prostatic adenomas with significantly lower morbidity, catheterization duration and length of stay. Performing holmium laser enucleation for large adenomas requires experience. Stress incontinence was seen frequently with laser but was short-term and self-limited. Holmium laser enucleation is a new procedure, and as experience and expertise increase, it may become an attractive alternative to open prostatectomy for patients with large prostate adenomas.

Holmium laser prostatectomy.

Holmium laser prostatectomy has evolved in the last decade to reproduce the short- and long-term results of both transurethral and open prostatectomy. This article discusses our surgical approach at the Methodist Hospital of Indiana as well as offers a review of the literature of holmium prostatectomy.

Helical CT of urinary calculi: effect of stone composition, stone size, and scan collimation.

OBJECTIVE: Helical CT has become the preferred methodology for identifying urinary calculi. However, the ability to predict stone composition, which influences patient treatment, depends on the accurate measurement of the radiographic attenuation of stones. We studied the effects of stone composition, stone size, and scan collimation width on the measurement of attenuation in vitro. MATERIALS AND METHODS: One hundred twenty-seven human urinary calculi of known composition and size were scanned at 120 kVp, 240 mA, and a 1:1 pitch at different collimations. A model, based on the physics of helical CT, was used to predict the effect of scan collimation width and stone size on measured attenuation. RESULTS: At a 1-mm collimation, stone groups could be differentiated by attenuation: the attenuation of uric acid was less than that of cystine or struvite, which overlapped; these were less than the attenuation of calcium oxalate monohydrate, which was in turn lower than that of brushite and hydroxyapatite, which overlapped and showed the highest values. At a wider collimation, attenuation was lower and the ability to differentiate stone composition was lost. Attenuation also decreased with smaller stones. At a 10-mm collimation, some uric acid stones (

Metabolic evaluation of stone disease patients: a practical approach.

In the last three decades, minimally invasive techniques have progressed significantly, replacing traditional open surgery as the mainstay of stone disease surgical treatment. The challenge for the next millennium remains medical prevention of calcium urolithiasis, a field where less dramatic progress has been achieved during the same period of time. The purpose of this article is to provide the practicing urologist with current practical guidelines for the assessment and management of calcium urolithiasis patients. The recommendations are based on the latest available information regarding the pathogenesis, medical treatment options, and decision-making rationale when managing these challenging patients. Every urolithiasis patient should undergo a basic evaluation, which is considered the minimal essential diagnostic work-up, in order to rule out obvious, treatable systemic causes of urinary stone disease. All patients should be advised about conservative nonspecific preventive measures. High-risk stone patients should have a more extensive metabolic evaluation based on two 24-hour urine samples. Treatment protocols for each patient are tailored individually according to the metabolic evaluation findings.

Expanding role of flexible nephroscopy in the upper urinary tract.

Flexible nephroscopy has become an important diagnostic and therapeutic modality for urologists. We have applied the flexible nephroscope in four clinical settings: as an adjunct to rigid instruments during primary percutaneous nephrolithotomy (PCNL); in a second-look procedure to remove residual renal calculi; as the primary endoscope to treat renal calculi; and to diagnose and treat other upper urinary tract pathology. The most common application of flexible nephroscopy in our experience has been during primary PCNL after the bulk of the stone burden has been removed with the rigid nephroscope. Liberal use of the flexible endoscope in these settings may increase the stone-free rate and decrease the need for additional access tracts and procedures. In addition, patients with conduit urinary diversions may be managed using flexible nephroscopy to diagnose and treat upper tract tumors.

Alterations in predicted growth rates of pediatric kidneys treated with extracorporeal shockwave lithotripsy.

The long-term effects of extracorporeal shockwave lithotripsy (SWL) on the kidneys of children treated for renal calculi are unclear. In order to determine if SWL has any negative effects on renal growth rates, we reviewed long-term (mean 9-year) follow-up data on 29 pediatric patients treated between 1984 and 1988 with an unmodified Dornier HM3 lithotripter. Changes in renal length, serum creatinine, and blood pressure were analyzed. Predicted renal growth was calculated using a formula for age-adjusted renal length. Treated kidneys were stratified into normal and abnormal groups based on a history of renal surgery, evidence of recurrent infection, and obvious anatomic abnormalities. Fifty-six upper urinary tract calculi were treated in 34 renal units. Twenty-two renal units (68%) were rendered stone free, and 65% of the patients continue to be stone free. At follow-up, one patient was classified as having new-onset hypertension, and the mean serum creatinine was 0.93 +/- 0.08 mg/dL. Both at treatment and at follow-up, no significant differences were found in the sizes of the treated and untreated kidneys. However, at treatment, the abnormal group of kidneys seemed to be smaller than expected (mean Z -1.30 +/- 1.10), whereas the group of normal kidneys was very close (mean Z 0.18 +/- 0.54) to the predicted length. At follow-up, the deviations between actual and predicted renal length were significantly more negative. Treated kidneys were an additional 1.26 +/- 0.49 SD units below their expected length (p = 0.02). Untreated kidneys were further below normal as well but possibly to a lesser degree (-0.82 +/- 0.36; p <0.04). Although there was a trend for the abnormal group to have smaller kidneys than the normal group, both groups showed the same trend toward an age-adjusted reduction in renal growth at follow-up. The alterations in renal growth patterns observed in this population are unsettling and could be secondary to either treatment effect (SWL) or, more likely, to some underlying pathology intrinsic to pediatric kidneys with urolithiasis. Until further data are available, SWL in the pediatric population should be applied with caution and at the lowest dosage sufficient to achieve stone comminution.

Lower-pole caliceal stone clearance after shockwave lithotripsy, percutaneous nephrolithotomy, and flexible ureteroscopy: impact of radiographic spatial anatomy.

Spatial anatomy of the lower renal pole, as defined by the infundibulopelvic angle (LIP angle), infundibular length (IL), and infundibular width (IW), plays a significant role in the stone-free rate after shockwave lithotripsy. A wide LIP angle, a short IL, and a broad IW, individually or in combination, favor stone clearance, whereas a LIP <70 degrees, an IL >3 cm, or an IW < or =5 mm are individually unfavorable. When all three unfavorable factors or an unfavorable LIP and IL coexist, the post-SWL stone-free rate falls to 50% or less. Using these criteria, more than one fourth of our patients with a lower-pole calculus might have been better served by an initial percutaneous or perhaps ureteroscopic procedure, neither of which is significantly affected by the lower-pole spatial anatomy.

Ureteral Stones Clinical Guidelines Panel summary report on the management of ureteral calculi. The American Urological Association.

PURPOSE: The American Urological Association convened the Ureteral Stones Clinical Guidelines Panel to analyze the literature regarding available methods for treating ureteral calculi and to make practice policy recommendations based on the treatment outcomes data. MATERIALS AND METHODS: The panel searched the MEDLINE data base for all articles related to ureteral calculi published from 1966 to January 1996. Outcomes data were extracted from articles accepted after panel review. The data were then meta-analyzed to produce outcome estimates for alternative treatments of ureteral calculi. RESULTS: The data indicate that up to 98% of stones less than 0.5 cm. in diameter, especially in the distal ureter, will pass spontaneously. Shock wave lithotripsy is recommended as first line treatment for most patients with stones 1 cm. or less in the proximal ureter. Shock wave lithotripsy and ureteroscopy are acceptable treatment choices for stones 1 cm. or less in the distal ureter. CONCLUSIONS: Most ureteral stones will pass spontaneously. Those that do not can be removed by either shock wave lithotripsy or ureteroscopy. Traditional blind basket extraction, without fluoroscopic control and guide wires, is not recommended. Open surgery is appropriate as a salvage procedure or in certain unusual circumstances.

Urologic applications of the Holmium laser.

The Holmium laser has now been in clinical use in urology for several years. The indications for its use continue to expand, and now include lithotripsy and urothelial tumor ablation anywhere in the urinary tract, resection of the prostate, incision of various urinary tract strictures, and vaporization of cutaneous lesions of the external genitalia. The 2100-nm wavelength provides the Holmium laser with a unique combination of vaporization and coagulation, allowing a precise cutting action when higher energy levels are applied. A shallow depth of penetration (< 0.5 mm) in water and tissue allows precise energy application and provides a margin of safety. The machine's user-friendly setup facilitates its operation by urologists and assistance by allied health-care personnel. The multiple urologic applications make the Holmium laser an attractive instrument for everyday utilization by any medium to large urological unit.

Lithotripsy and surgery.

Advances in surgical techniques have dramatically altered the management of patients with symptomatic urolithiasis requiring intervention. Extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy, and ureteroscopy allow virtually any stone to be removed from the upper urinary tract without resorting to open surgical techniques. Extracorporeal shock wave lithotripsy is the preferred initial treatment for approximately 80% to 85% of calculi. Percutaneous nephrolithotomy is the preferred approach when dealing with more voluminous stone material (ie, > 2 cm). Ureteroscopy is generally reserved for distal ureteral calculi, although the recent advent of small flexible ureteroscopes have extended ureteroscopic techniques effectively into the proximal ureter and even the kidney. Staghorn stones are usually best managed initially with percutaneous nephrolithotomy followed by the addition of extracorporeal shock wave lithotripsy, if necessary. The relative advantages, disadvantages, and complications of extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy, and ureteroscopy will be reviewed.

Value of laparoscopy in the management of calculi complicating renal malformations.

A minimally invasive approach for urolithiasis patients with complex anatomic abnormalities occasionally necessitates the use of laparoscopic techniques, either alone or in combination with endourologic techniques. The management of these patients is best accomplished in centers with the facilities to provide a spectrum of endourologic and laparoscopic techniques. Two illustrative cases are described.

Endoscopic management of total ureteral occlusion and ureterovaginal fistula.

Between August 1991 and June 1994, endoureterotomy was performed in nine patients for total ureteral occlusion. Four of these patients had an associated ureterovaginal fistula. The total ureteral occlusions were iatrogenic in eight patients and the result of trauma in one. The prone split leg position was used to facilitate simultaneous antegrade and retrograde ureteroscopy in all nine patients. The "cut-to-the-light" technique was utilized in six patients and a new technique employing a fascial incising needle was used in five patients. Five patients developed ureteral strictures within 5 months of the primary procedure that were corrected endoscopically. With a mean follow-up of 22 months, all nine patients have a successful outcome. Endoscopic management of difficult urteral disease such as total urteral occlusion and ureterovaginal fistula is a useful alternative to open surgery.

Percutaneous nephrolithotomy directly through an angiomyolipoma.

We present a patient with tuberous sclerosis and bilateral angiomyolipomas with a right partial staghorn calculi in which the calculi was managed with a percutaneous nephrolithotomy. Despite the inherent risk of hemorrhage with a percutaneous approach compounded by the fact that this was done directly through a tumor, we were able to render the patient stone free with no intraoperative bleeding, complications, or the need for postoperative blood transfusion. To our knowledge, this is the first reported case of percutaneous nephrolithotomy directly through a renal angiomyolipoma.

Laparoscopic retroperitoneal needle suspension urethropexy.

Recent advances in laparoscopic surgery have allowed urologists to perform laparoscopic bladder suspension; however, laparoscopic suturing techniques have a steep learning curve and make the procedure more difficult and time consuming. We describe a new technique that combines extraperitoneal laparoscopic bladder neck mobilization through a single port with the ease of a needle suspension urethropexy in order to avoid the need for vaginal incisions and the use of laparoscopic suturing techniques. The procedure has been performed in four patients, all of whom are continent and voiding with complete bladder emptying. Postoperative pain was minimal, allowing most patients to be discharged the day after surgery. In the future, the procedure may be performed on an outpatient basis.

Nephrolithiasis Clinical Guidelines Panel summary report on the management of staghorn calculi. The American Urological Association Nephrolithiasis Clinical Guidelines Panel.

The American Urological Association Nephrolithiasis Clinical Guidelines Panel recommendations for managing struvite staghorn calculi are based on a comprehensive review of the treatment literature and meta-analysis of outcome data from the 110 pertinent articles containing viable, unduplicated data. The panel concluded that the 3 most significant outcome probabilities are those of being stone-free, undergoing secondary unplanned procedures and having associated complications. Panel guideline recommendations for most standard patients are that neither shock wave lithotripsy monotherapy nor open surgery should be a first-line treatment choice but that a combination of percutaneous stone removal and shock wave lithotripsy should be used.