Report of the United States cooperative study of extracorporeal shock wave lithotripsy

Extracorporeal shock wave lithotripsy effectively fragments urinary calculi in the upper urinary tract and upper ureter. These fragments pass completely by 3 months in 77.4 per cent of the patients with single stones. Risk of obstruction, increased postoperative pain, need for additional urological operations and retained fragments are low for stones less than 1 cm. in size. As the number of stones treated or single stone size increases above 1 cm. the risk for these factors increases. Adjunctive urological surgical management is required in 9 per cent of the patients preoperatively and 8 per cent postoperatively. Only 0.6 per cent of the patients require some type of open operation to resolve the stone problems after extracorporeal shock wave lithotripsy. Hemorrhage, obstruction by fragments, severe pain and urinary infection all constitute known complications and require careful urological management of all patients. Hospitalization averages 2 days after treatment and patients usually return to work within a few days after they are discharged from the hospital.

Experience with new double J ureteral catheter stent

Experience with a newly designed self-retaining silicone ureteral stent is presented. The stent is supplied in various lengths, has a J or hook molded into each end to prevent migration and has been designed specifically to be passed during an open operation as well as endoscopically. The device is used to provide free drainage to the bladder, reduce or eliminate urine leakage, provide stenting of the ureter and allow for earlier discharge from the hospital of patients without external catheters. In some cases the stent may be used instead of a nephrostomy tube to provide prolonged drainage with less chance of infection. It is removed easily in the outpatient facility by cystoscopy.

Urinary infection stones

Infection stones make up approximately 15% of urinary stone diseases and are thus an important group. These stones are composed of struvite and/or carbonate apatite. The basic precondition for the formation of infection stones is a urease positive urinary tract infection. Urease is necessary to split urea to ammonia and CO(2). As a result, ammonia ions can form and at the same time alkaline urine develops, both being preconditions for the formation of struvite and carbonate apatite crystals. When these crystals deposit themselves infection stones form. If these infections are not treated and the stones are not removed, the kidney will be damaged. For stone removal modern methods are available, e.g. ESWL and/or instrumental urinary stone removal. Here especially less invasive methods are preferable. Any treatment must be adjusted to the patient individually. Patients should be examined frequently for recurrent urinary tract infections and stone recurrences and, newly arising infections must be resolutely treated. Good therapy and prophylaxis are possible with present-day treatment modalities.

Lithogenic properties of enterocystoplasty

Calculi formed in 26 of 87 patients (30%) following augmentation enterocystoplasty, of which 23 formed within the reservoir, at a mean interval of 25 months postoperatively. The calculi were composed principally of triple phosphates suggesting an important etiological role of bacteriuria and the urease reaction. Open cystolithotomy was the most successful means of removing the calculi.

Primary urethral reconstruction: the cost minimized approach to the bulbous urethral stricture

PURPOSE

Treatment for urethral stricture disease often requires a choice between readily available direct vision internal urethrotomy (DVIU) and highly efficacious but more technically complex open urethral reconstruction. Using the short segment bulbous urethral stricture as a model, we determined which strategy is less costly.

MATERIALS AND METHODS

The costs of DVIU and open urethral reconstruction with stricture excision and primary anastomosis for a 2 cm bulbous urethral stricture were compared using a cost minimization decision analysis model. Clinical probability estimates for the DVIU treatment arm were the risk of bleeding, urinary tract infection and the risk of stricture recurrence. Estimates for the primary urethral reconstruction strategy were the risk of wound complications, complications of exaggerated lithotomy and the risk of treatment failure. Direct third party payer costs were determined in 2002 United States dollars.

RESULTS

The model predicted that treatment with DVIU was more costly (17,747 dollars per patient) than immediate open urethral reconstruction (16,444 dollars per patient). This yielded an incremental cost savings of $1,304 per patient, favoring urethral reconstruction. Sensitivity analysis revealed that primary treatment with urethroplasty was economically advantageous within the range of clinically relevant events. Treatment with DVIU became more favorable when the long-term risk of stricture recurrence after DVIU was less than 60%.

CONCLUSIONS

Treatment for short segment bulbous urethral strictures with primary reconstruction is less costly than treatment with DVIU. From a fiscal standpoint urethral reconstruction should be considered over DVIU in the majority of clinical circumstances.

Urolithiasis in 68 horses

Medical records of 68 horses with urolithiasis were examined. Calculi were in the bladder in 47 horses, urethra in 11 horses, kidneys in 15 horses, and ureter in two horses. They occurred at several sites in six horses. Common clinical signs included hematuria, altered micturition (pollakiuria, dysuria, urinary incontinence), and tenesmus. Weight loss, possibly attributable to chronic renal failure and colic, was associated more commonly with renal and ureteral calculi. Weight loss also occurred in 13% of horses with cystic calculi only. In male horses, most cystic calculi were removed by perineal (ischial) urethrotomy under epidural anesthesia. Although there were few surgical complications with urethrotomy, seven of 15 horses with follow-up suffered recurrent urolithiasis.

Percutaneous stone extraction from 200 patients

More than 200 patients have undergone percutaneous stone extraction at our institution. With the percutaneous nephrostomy tract as the conduit to the urinary tract we have removed 95 per cent of the pelviocaliceal stones and 80 per cent of the ureteral stones with grasping forceps, baskets, ultrasonic lithotripsy or a combination of these procedures. Complications were few and patients returned to work sooner than after an open operation.

Assessment of basic endoscopic performance using a virtual reality simulator

BACKGROUND

The objective of this study was to evaluate the effect of supervised training using a state-of-the-art virtual reality (VR) genitourinary endoscopy simulator on the basic endoscopic skills of novice endoscopists.

STUDY DESIGN

We evaluated 21 medical students performing an initial VR case scenario (pretest) requiring rigid cystoscopy, flexible ureteroscopy with laser lithotripsy, and basket retrieval of a proximal ureteral stone. All students were evaluated with objective parameters assessed by the VR simulator and by two experienced evaluators using a global rating scale. Students were then randomized to a control group receiving no further training or a training group, which received five supervised training sessions using the VR simulator. All students were then evaluated again in the same manner using the same case scenario (posttest).

RESULTS

Comparing the results of pre- and posttests, no major differences were demonstrated for any variable in the control group. In the trained group, posttest results revealed statistically significant improvement from baseline in the following parameters: total procedure time (p = 0.002), time to introduce a ureteral guidewire (p = 0.039), self-evaluation (p < 0.001), and evaluator assessment (p < 0.001). Comparing the posttest results of the control and trained arms, we found significantly better posttest scores in the trained group for the following parameters: ability to perform the task (p = 0.035), overall performance (p = 0.004), and total evaluator score (p < or = 0.001).

CONCLUSIONS

Students trained on the VR simulator demonstrated statistically significant improvement on repeat testing, but the control group showed no improvement. Endourologic training using VR simulation facilitates performance of basic endourologic tasks and might translate into better performance in the operating room.

Extracorporeal shock-wave lithotripsy: one-year experience with the Dornier lithotripter

Extracorporeal shock-wave lithotripsy (ESWL) has now been in clinical use for more than 4 years. In October 1983, the second kidney lithotripter in the world was installed in our department and, from then until October 1984, 800 treatments were performed on 733 patients. Our results confirm the promising reports published by the Munich group. Furthermore, it was possible to extend the range of indications by combining ESWL with percutaneous procedures, such as percutaneous nephrolithotomy and ureteroscopy. As a result only 7% of all patients who were referred to our hospital with urinary stones (4% of renal stone patients and 15% of those with ureteral stones) had to undergo open surgery.

Severe sepsis following percutaneous or endoscopic procedures for urinary tract stones

Nine cases of severe sepsis following percutaneous or endoscopic procedures for upper urinary tract stones are reported. The mortality rate was 66%. Despite the fact that approximately 700 procedures were carried out in males and females in roughly equal proportions, a striking but inexplicable feature was that all 9 patients in the study group were female. Severe systemic sepsis has a high mortality rate and any procedure that may put patients at risk of this complication should not be undertaken lightly (and certainly not as an out-patient procedure). Recovery is possible with a high index of suspicion, early intervention and intensive treatment.

Urinary tract stones in pregnancy

The presence of stones during an otherwise uneventful pregnancy is a dramatic and potentially serious issue for the mother, the fetus, and the treating physicians alike. The incidence and predisposing factors are generally the same as in nonpregnant, sexually active, childbearing women. Unique metabolic effects in pregnancy such as hyperuricuria and hypercalciuria, changes in inhibitors of lithiasis formation, stasis, relative dehydration, and the presence of infection all have an impact on stone formation. The anatomic changes and physiologic hydronephrosis of pregnancy make the diagnosis and treatment more challenging. Presenting signs and symptoms include colic, flank pain, hematuria, urinary tract infection, irritative voiding, fever, premature onset or cessation of labor, and pre-eclampsia. The initial evaluation and treatment are again similar to those used for the nonpregnant population. The most appropriate first-line test is renal ultrasonography, which may, by itself, allow the diagnosis to be made and provide enough information for treatment. Radiographic studies, including an appropriately performed excretory urogram, give specific information as to size and location of the stones, location of the kidneys, and differential renal function and can be used safely, but the ionizing radiation risks should be considered. All forms of treatment with the exception of extracorporeal shock wave lithotripsy and some medical procedures are appropriate in the pregnant patient. Close coordination by the urologist, the obstetrician, the pediatrician, the anesthesiologist, and the radiologist is required for the appropriate care of these patients.

Does the Size of Ureteral Stent Impact Urinary Symptoms and Quality of Life? A Prospective Randomized Study

OBJECTIVE

To evaluate the effect of stent diameter on patients' symptoms and quality of life (QoL) by using dedicated questionnaires.

METHODS

We prospectively enrolled 34 patients with unilateral ureteral obstruction due to urinary stone undergoing to ureteral stenting (17 pts with 4.8 F and 17 pts with 6 F) before treatment of stone disease. Twenty-one patients with lower urinary symptoms from other causes were used as a control group. Two questionnaires, one on QoL and another on stent specific symptoms, were administered to patients one week after stent positioning and 4 week after removal.

RESULTS

There was a significant association between stent state and answers on pain and discomfort on QoL questionnaire. A high percentage of patients reported anxiety and depression associated with the stent. Similar significant association was found between stent state and urinary symptoms and pain. No differences in QoL and urinary symptoms and pain were detected using stents with different size.

CONCLUSIONS

Ureteral stents are invariably associated with urinary symptoms and impaired QoL. We did not find any difference between stent with different size, whereas there was a tendency for stent with smaller diameter to dislodge more often.

PEDIATRIC UROLITHIASIS: 15 YEARS OF LOCAL EXPERIENCE WITH MINIMALLY INVASIVE ENDOUROLOGICAL MANAGEMENT OF PEDIATRIC CALCULI

PURPOSE

We sought to identify whether changes in technology and local practice have improved outcomes in the minimally invasive management of pediatric stone disease.

MATERIALS AND METHODS

We reviewed retrospectively case notes and imaging from 1988 to 2003, noting treatment modality, stone-free rates, ancillary therapy and complications.

RESULTS

A total of 122 children (140 renal units) with a mean age of 7.7 years underwent 209 extracorporeal shock wave lithotripsy (SWL) sessions. Stone size ranged from 6 to 110 mm. Stone-free rates were 84% for cases involving stones smaller than 20 mm, and 54% for those involving stones 20 mm or greater. For complex calculi 40% of patients were stone-free and 45% required ancillary procedures, with an overall complication rate of 26%. A total of 37 children (43 renal units) with a mean age of 6.4 years underwent 46 percutaneous nephrolithotomies (PCNLs). Stone size ranged from 8 to 155 mm. The overall stone-free rate was 79%. Of these patients 34% required ancillary procedures, with a major complication rate of 6%. A total of 35 children (35 renal units) with a mean age of 5.9 years underwent 53 ureteroscopies. Holmium laser was the most effective treatment modality in this group, with a 100% stone-free rate and no complications.

CONCLUSIONS

For most renal stones smaller than 20 mm SWL was the most effective primary treatment modality. There was no statistical difference between the 2 lithotriptors for stone-free or ancillary procedure rate. The stone-free rate was dependent on stone size rather than type of lithotriptor. For renal stones 20 mm or greater and staghorn calculi we switched from SWL to PCNL as primary treatment, as stone-free rates were higher and the ancillary procedure and re-treatment rates were lower with PCNL. Electrohydraulic lithotripsy and pulse dye laser were initially used to treat ureteral stones. However, with the introduction of holmium laser technology we achieved higher stone-free rates and lower complication rates. Holmium laser lithotripsy is now used as a primary treatment modality for ureteral stones.

Percutaneous management of urolithiasis during pregnancy

A total of 6 pregnant women with obstructing urinary calculi was managed by percutaneous nephrostomy drainage placed under ultrasound guidance with the patient under local anesthesia. All patients initially had relief of acute obstruction. However, occlusion of the percutaneous nephrostomy tubes with debris necessitated tube changes in 5 of 6 patients. In 2 patients recurrent nephrostomy tube obstruction, fever and pain led to percutaneous stone removal during pregnancy. In the remaining 4 patients the nephrostomy tubes were left indwelling through delivery. During the postpartum period 3 patients successfully underwent ureteroscopic stone extraction and 1 passed the stone spontaneously. Bacteriuria developed in each patient despite the use of preventive antibiotics. All 6 women had uncomplicated vaginal deliveries of healthy newborns and are currently asymptomatic with no evidence of obstruction. Percutaneous drainage of an acutely obstructed kidney in a pregnant woman is an effective temporizing alternative to ureteral stent placement until definitive treatment can be performed.

Comparison of Results of Virtual-Reality Simulator and Training Model for Basic Ureteroscopy Training

BACKGROUND AND PURPOSE

The traditional method of acquiring surgical skills is by apprenticeship and involves an extensive period of training with patients. Model-based and virtual reality simulation is gaining interest as alternative training, allowing repetitive practice in a low-risk environment. The objective of this study was to determine if a materials, model-based training format and an interactive virtual-reality simulator could provide equivalent teaching of basic ureteroscopy skills to the inexperienced medical student.

SUBJECTS AND METHODS

Sixteen first-year medical students received the same didactic session and video viewing on cystoscopy, guidewire access to the upper urinary tract, and ureteroscopy with intracorporeal laser lithotripsy and stone extraction by the same instructor. The participants were then randomized into two study groups: Group 1 was trained on the ureteroscopy training model (TMU) from Limbs & Things and Group 2 on the Simbionix UROMentor virtual-reality simulator (VRS) until the participants could perform the procedure independently. Two months later, the participants independently performed a ureteroscopic procedure on a pig kidney/ureter model and were graded from 1 to 5 on their ability to complete the steps of the procedure and the quality of their performance (handling of tissue, efficiency, instrument handling, knowledge of instruments, flow of operation, use of assistants, and knowledge of the specific procedure) for a possible total of 35 points.

RESULTS

All participants were able to perform the steps of the procedure correctly. The TMU group and the VRS group received a mean of 22.9 +/- 4.8 and 23.6 +/- 5.4 points, respectively (P = 0.38) for their qualitative assessment.

CONCLUSION

The medical students' skills and ability to perform a basic ureteroscopic stone-management procedure was independent of the training modality (VRS or TMU). Incorporating either of these devices into the preliminary training of urology residents may improve their initial clinical performance of these skills.

Redefinitions of indications for percutaneous nephrostomy

An analysis of treatment response in 215 patients treated by percutaneous nephrostomy identified obstruction of the urinary tract, complicated by infection and sometimes gram-negative septicemia, as the single most important indication for this intervention. Percutaneous nephrostomy reduced the mortality from gram-negative septicemia from 40% to 8%. Similarly, the length of hospitalization for patients with severe infection complicating urinary tract obstruction was reduced by half in the group undergoing percutaneous nephrostomy. In 43 patients with longstanding obstruction, percutaneous nephrostomy was used to predict recoverable renal function based on the response of renal plasma flow rate to decompression. In 13 patients, percutaneous nephrostomies were used either for the introduction of solvents to dissolve calculi or to serve as pathways for their extraction. Percutaneous nephrostomies in 21 patients were expanded to serve as points of entry for the placement of stent catheters to treat fistulas or bougie catheters to dilate and subsequently catheterize ureteral strictures. While six serious complications were encountered, five of these might have been prevented by meticulous adherence to proper technique.

A Prospective Case-Control Study Comparing LithoVue, a Single-Use, Flexible Disposable Ureteroscope, with Flexible, Reusable Fiber-Optic Ureteroscopes

OBJECTIVE

LithoVue™ is a novel, single-use, digital flexible ureteroscope that was released to the US market in January 2016. There are scant data regarding its performance in humans. Procedural outcomes comparing LithoVue with reusable ureteroscopes are presented in patients undergoing ureteroscopy for upper urinary tract pathology.

PATIENTS AND METHODS

Clinical outcomes between two groups of patients undergoing flexible ureteroscopy for upper urinary tract pathology were analyzed. The first group underwent surgery utilizing LithoVue, and the second group used reusable fiber-optic flexible ureteroscopes. Differences in procedural outcomes, operative times, and time spent in hospital were analyzed using two-tailed t-tests and chi-squared and Fisher's exact tests.

RESULTS

One hundred fifteen cases utilizing LithoVue and 65 cases utilizing reusable ureteroscopes were included in this study. Demographics, surgical indications, stone size, location, total stone burden, composition, procedural outcomes, and complications were comparable between groups. For all cases, LithoVue procedures lasted 54.1 ± 25.7 minutes compared with 64.5 ± 37.0 minutes for reusable scope procedures (p < 0.05) and for stone removal cases, 57.3 ± 25.1 vs 70.3 ± 36.9 minutes, respectively (p < 0.05). Scope failure occurred in 4.4% of LithoVue cases and 7.7% of reusable cases (p = 0.27).

CONCLUSIONS

LithoVue represents a feasible alternative to reusable ureteroscopes with a low rate of scope failure comparable with reusable ureteroscopes. Its use shortens procedure duration, a finding that warrants further investigation.

Childhood urolithiasis in Britain

120 children with urinary calculi were treated between 1966 and 1971. 75% were male, and the median age of diagnosis was 3 years. In 34 there were associated urological abnormalities and in 8 a metabolic cause of calculi was identified. 12 of 67 children had hypercalciuria. In 95 children the urine was infected on admission to hospital; in 76, particularly the younger children, this was with Proteus species. Calculi recurred after surgery in 13 children, and in 9 the only identifiable factor was failure to eradicate the Proteus infection.

Clinical experience with pediatric urolithiasis

Our clinical experience with 47 pediatric patients with stones is reviewed. Surgical therapy was standard with successful stone manipulation in 12 of 13 patients. In 91 per cent of our patients factors causing or predisposing to stone disease were discovered. A thorough metabolic evaluation, including an oral calcium loading test in 20 children, proved to be helpful. A new patient subgroup relating unexplained hematuria to eventual stone formation is described. Our protocol for metabolic evaluation and recommendations for treatment based on the results of such an evaluation are given. We have found the metabolic evaluation of the child with stones meaningful and particularly helpful in planning subsequent therapy for these patients.

Ex vivo comparison of four lithotripters commonly used in the ureter: what does it take to perforate?

We hoped to determine the number of pulses and energy needed to create acute ureteral perforations with four different lithotripters in a reproducible ex vivo model. A simple model was constructed to control variables in the testing such as wall thickness, intraluminal pressure, distance between the probe tip and ureter, and power delivered to tissue. Segments of domestic pig ureter were prepared and fixed in position in a normal saline (NS) bath at room temperature. We then attempted perforation with the holmium:YAG (HoL) laser, coumarin pulsed-dye laser (CdL), electrohydraulic lithotripter (EHL), and pneumatic impactor (PI) by placing the instrument probes at right angles to the ureteral wall. The ureter was filled with a methylene blue-stained solution of NS at 90 cm H2O pressure via a urodynamics catheter, and perforation was recorded on initial extravasation of dye. The endpoints measured were time to perforation and total energy required. At 0.5 mm of separation between the wall and probe, the HoL perforated the ureter in an average of 2 seconds and 0.01 kJ delivered at 5 W (10 Hz and 0.5 J/pulse). The EHL perforated at an average of 24.44 +/- 8.77 seconds and a total energy of 0.01 +/- 0 kJ. The CdL was able to perforate but at much longer intervals (257.51 +/- 99.08 seconds) and higher energy levels (12.88 +/- 4.95 kJ) on average than either the EHL or HoL. Lastly, the PI was unable to perforate the ureter in more than 6 continuous minutes of application. In addition, we found that at 2-mm separation between the HoL probe tip and the ureteral wall, acute perforation was not possible even at very high power settings. We conclude that although each endoscopic lithotripter has advantages as well as disadvantages, in this ex vivo model, it was clear that the HoL and EHL can easily perforate the ureter and must be used with vigilance. It was found that at 2 mm of separation between the probe and target, the HoL, was unable to perforate acutely. The CdL and PI were associated with a much higher safety index, and the PI was unable to produce ureteral perforation.

Urolithiasis in childhood: current management

During the past 12 years, 62 children with urinary stones have been treated at the Children's Hospital of Philadelphia. The most common presenting symptoms were abdominal or flank pain (45%), recurrent or persistent pyuria (35%), and gross hematuria (21%). Twenty-two patients had associated congenital urologic anomalies. Infection-related struvite stones were most common and were found in 18 children, of whom 15 were found to have anatomic abnormalities. Eighteen of 28 children evaluated for a metabolic cause were found to have an abnormality, most frequently hypercalciuria. No predisposing factors could be found in 16 of the 62 patients. Forty-four (87%) children had upper urinary tract stones. Twelve of 15 bladder stones were in children with a neuropathic bladder and all were related to infection. Treatment was directed to the correction of anatomic and metabolic predisposing causes, as well as to removing the stones. Fifteen patients passed stones ranging in size from 2 to 6 mm. Forty-six surgical procedures were performed in 43 children. Pyelolithotomy and cystolithotomy were the most frequent procedures. There were three residual stones and five recurrences. Of the 29 operations for upper urinary stones reviewed, 17 might today be considered suitable for percutaneous nephrostolithotripsy or extracorporeal shockwave lithotripsy. Possible future stone management will be discussed in light of this analysis.

Experience with childhood urolithiasis. Report of 196 cases

A total of 196 children with urinary calculi were treated surgically. Their ages ranged from 1 to 14 years. The male:female ratio was 3:1. Stones were located in the kidney in 96 patients, in the bladder in 52 and in the ureters in 32. Multiple organ involvement was present in 16 patients and associated urinary tract anomalies were found in 11. Stone analysis revealed calcium oxalate and phosphate stones in 121 patients, struvite stones in 60 and uric acid stones in 15.

Fluid absorption during urological endoscopy

Transurethral prostatectomy (TURP) and, more recently, percutaneous nephrolithotomy and endoureteric procedures for stones in the kidney and ureter have justifiably become popular because of the many advantages offered by these less invasive procedures. Any surgical operation has its attendant complications and absorption of irrigant fluid is a major and potentially fatal complication of all of these endoscopic techniques. This review examines the incidence, the causes and the pathological sequelae of excessive fluid absorption and suggests some ways to prevent it.