Ultrasonic velocities of concentric laminated uric acid stones.

In concentric laminated uric acid samples two different sound velocities are observed with very different values, the one in the organic matrix varies from 670 to 1170 m s(-1), the other in the crystalline layers between 3200 and 5300 m s(-1). This large difference illustrates the importance of the internal stone structure on the fracture behaviour of urinary stones and reveals the weakness of the actual disintegration models, attributing the destructive effect of shock waves on the differences in acoustical impedance at the water/stone interface and not on the differences in acoustical impedance at the matrix/crystalline interfaces inside the urinary calculus.

Importance of the implosion of ESWL-induced cavitation bubbles.

The damage induced by an extracorporeal shock wave lithotripter is observed with a fiber optic stress sensing technique. When a stone is placed in the focus, besides the expected stress induced by the incoming shock wave emitted by the ESWL apparatus, a second delayed stress is observed some hundreds of microseconds later. The second stress is induced by a shock wave generated at the collapse of a cavitation bubble. Partial reflection of the incoming shock wave at the stone boundary is at the origin of the large cavitation bubble formation. Sensing fiber fracture results always from the second shock wave due to the collapse of the cavitation bubble. Thus the largest stress is generated at the collapse. When no target is placed in the focus of the lithotripter, no large cavitation bubble is formed and no delayed shock wave is observed. Our results demonstrate unambiguously the decisive role of cavitation in ESWL procedures.

Macroscopic ESWL-induced cavitation: in vitro studies.

The rarefaction shock wave results in a liquid failure at the target/fluid interface. In the wake of the reflected ESWL-induced shock wave, a macroscopic cavity is generated in filtered water. The cavity implosion induces a large shock wave, divulging the bubble existence and lifetime. The existence of this shock wave is revealed by the diffraction of a He-Ne laser beam. The induced cavitation bubbles are registered by a camera, illuminated by an externally triggered stroboscope (exposure time 10 microseconds). The radius of the large cavity bubble, generated at the stone surface, is time dependent as theoretically predicted.

Exophytic papillary prostatic duct adenocarcinoma with endometrioid features, occurring in prostatic urethra after TURP.

We present an eighty-three-year-old man with an exophytic lesion in the prostatic cavity, diagnosed three years after transurethral resection of the prostate, and extending into the bladder. Histopathologically, the tumor was recognized as a papillary ductal adenocarcinoma (primary duct type) with endometrioid features, probably associated with prostatic adenomatous polyp. Acinic adenocarcinoma was absent. The lesion was treated by deep transurethral resection with objective follow-up results after six months. Review of the literature concerning history, embryology, possible pathogenesis, differential diagnosis, and treatment options is included.

The influence of internal stone structure upon the fracture behaviour of urinary calculi.

In vitro extracoporeal shock wave lithotripsy (ESWL) on different types of urinary calculi, in combination with microfocus x-ray and microphotography, illustrates the importance of the internal stone structure. Calculi with a rough surface layered structure (calcium oxalate monohydrate) and untextured calculi (cystine) are characterized by a low stone fragility, whereas coarse-grain calculi (calcium oxalate dihydrate, struvite), and calculi with a smooth surface layered structure (uric acid), are very fragile. Shell-like fragmentation in layered calculi, with smooth surface of the crystalline laminations, suggests that the stone matrix influenced the propagation of the shock wave energy inside the stone.

In vitro analysis of urinary calculi: type differentiation using computed tomography and bone densitometry.

Thirty-six urinary stones were studied by computed tomography and bone densitometry in order to find a correlation between the chemical composition of the stones and the densitometric data. In vitro, the more common cases of lithiasis can be divided into 3 main groups: uric acid, cystine and the calcium salts, e.g. calcium oxalate monohydrate, calcium oxalate dihydrate and calcium phosphate. Struvite stones fall between the second and third groups. Computed tomography and bone densitometry can differentiate between the groups, provided that the value of the "stone mineral or calcium content" is correlated with the true calculated volume of the stone (resulting in the specific stone density) instead of the projection area (resulting in the area density). This is only possible in vitro. The in vivo application of these technologies in the treatment of stones of unknown composition could provide important information, but major restrictive factors pose difficulties. Further clinical studies are necessary, especially to define the role of bone densitometry.

Stone geometry and structure dependence on extracorporeal shock wave lithotripsy.

The in vitro fragmentation effects of electromagnetic-induced shock wave lithotripsy (Siemens Lithostar) were studied on parallel laminated schists in relation to the incoming shock wave energy and the incoming angle of the incident shock wave. Well above the threshold energy, the total amount of acoustic energy required for fragmentation remained unchanged regardless of the power setting of the high-tension supply. The amount of energy transmitted to the stone was limited by a total reflection angle, restricting the available transmission surface. These observations determine the effect of shock waves on calculi with an irregular shape such as staghorn stones. Lithotripsy-induced cavitation has been recognized, but no immediate influence on disintegration has become apparent until now.

Long-term consequences of urethral stents.

The results of the self-expandable urethral stent (Wallstent) in the treatment of urethral strictures were evaluated in 7 patients with a followup of 23 to 31 months. The 4 failures were caused by exuberant fibrotic proliferation in the lumen of the stent, which required further endoscopic treatment in 2 patients and even surgical removal of the stent in 1. In the other 2 patients the fibrotic proliferation was progressive and will require further treatment. In 1 patient there is slowly progressive proliferation and a diminishing urine flow rate, and in 2 the fibrotic proliferation seems to be stable. Early reports on the stent suggest that its use will obviate the necessity for complex surgery of urethral stricture. Strictures involving layers deeper than the urothelium and traumatic strictures are not good indications for the self-expandable stent. As this technology continues to evolve, we must continue to follow these patients closely and be attentive to the possible long-term consequences.

High pressure versus low pressure electromagnetic extracorporeal lithotripsy.

A low pressure and an upgraded high pressure electromagnetic lithotriptor were compared for the treatment of calculi within the ureter. The upgrading allows for increased energy density onto the stone surface. We targeted 139 ureteral calculi (average diameter 8.1 mm.) with the low pressure system. The mean number of shock waves was 7,308, 9,226 and 5,304 for calculi in the upper, mid and lower ureter, respectively, and the energy density corresponded to 0.222, mJ./mm.2, 0.224 mJ./mm.2 and 0.223 mJ./mm.2, respectively. Immediate fragmentation was achieved in 39 of 51 upper (77%), 21 of 42 mid (50%) and 22 of 46 lower (49%) ureteral calculi. The upgraded shock wave tube was used in 52 calculi (average diameter 6.1 mm.). The mean number of shock waves was 6,250, 14,150 and 3,400 for calculi in the upper, mid and lower ureter, respectively, and the energy density corresponded to 0.32 mJ./mm.2, 0.33 mJ./mm.2 and 0.30 mJ./mm.2, respectively. Immediate fragmentation was achieved in 11 of 16 upper (69%), 4 of 6 mid (67%) and 7 of 30 lower (23%) ureteral calculi. The comminution rate did not significantly increase, which implies that the focal energy density is not the only decisive parameter in fragmentation by extracorporeal shock wave lithotripsy.

Prophylactic role of extracorporeal shock wave lithotripsy in the management of nephrocalcinosis.

Electromagnetic extracorporeal shock wave lithotripsy (ESWL) was performed with a standard Siemens Lithostar on parenchymal calcifications in 10 medullary sponge kidneys in order to evaluate the eventual benefit of preventive lithotripsy. The results of shock wave lithotripsy on precaliceal calcifications were disappointing and have been related to the lack of expansion during shock wave interaction and to the impaired drainage of particles. Three patients also had large impacted ureteric stones and in such cases ESWL remains the treatment of choice.

Surgical versus endoscopic treatment of non-malignant uretero-ileal anastomotic strictures.

The classical treatment of uretero-ileal anastomotic strictures after Bricker uretero-ileostomy is open surgical revision. Recent progress in endourology has provided a number of alternatives. The success rate of these endoscopic techniques is less than the success rate of the open surgical revision.

Submucosal migration of ureteric calculi: related to ESWL?

Three patients were reinspected by ureteroscopy after repeat ESWL. Ureteroscopy initially did not disclose an intraluminal stone and only visualized a severe inflammatory reaction of the ureteric wall and a boss of the ureter at the level of the fluoroscopically suspected stone location. An intact stone in all 3 cases was finally exposed by tactile contact at the top of the ureteroscope after perforating the mucosa with a guide wire. Retrospectively, the combination of long-standing stone impaction together with damage to the ureteric mucosa during shockwave interaction may cause an inflammatory reaction with submucosal migration of the stone.

Electromagnetic extracorporeal shock wave lithotripsy for calculi in horseshoe kidneys.

Between June 1987 and January 1991, 11 renal units in 10 patients with horseshoe kidneys were managed by electromagnetic extracorporeal shock wave lithotripsy (ESWL) monotherapy with a Siemens Lithostar. A total of 33 calculi was treated in 42 sessions. All treatments were performed without anesthesia and on an outpatient basis. All calculi could be targeted by standard installation techniques. The maximum number of shock waves per session was 4,000, which implies per stone an average of 1.3 sessions and an average of 4,903 shock waves (range 1,800 to 9,000) at a mean energy setting of 17.8 kv. Complete disintegration or fragmentation into spontaneously passable particles was achieved in 27 calculi, for a success rate of 83% when considering the results in regard to the individual stone locations. Per renal unit, an average of 3 calculi were targeted and after an average of 3.8 sessions 6 units became stone-free. Horseshoe kidneys, when calculous, contain dispersed and multiple calculi and from these data approximately 1 session per stone must be planned. The number of treatments per renal unit increased in proportion to the number of calculi and to the presence of calculi with low fragility. Of 21 lower pole calculi 18 completely evacuated and this observation has been related to the more medial location of the inferior calices near the ureteropelvic junction. No impaired drainage of fragments was noted to be related to the horseshoe anatomy. Patency of the ureteropelvic anatomy appeared to be the main parameter for the evacuation of fragments. Neither preoperative nor postoperative adjuvant maneuvers have been necessary.

[Urinoma: a complication of celiac plexus infiltration]. / L'urinome: une complication de l'infiltration du plexus coeliaque.

A case is described in which a major complication resulted from this technique. We have found no previous record of urinoma due to infiltration of a caustic agent.

A pseudotumoral edema of the urinary bladder secondary to an intramural impacted ureteral lithiasis.

A case of pseudotumor of the urinary bladder secondary to intramural lithiasis is reported. Computer tomography, cystoscopy of the mass and cytology suggested a malignant tumor. A transurethral biopsy from the tumor was therefore performed, but it showed tissue covered with normal transitional cell epithelium but no signs of malignancy. Pseudotumoral edema of the bladder is easily mistaken for a malignant neoplasm (1, 2, 3).

Effect of alkalinization on calcium oxalate monohydrate calculi during extracorporeal shock wave lithotripsy: in vivo experiments.

Previous in vitro experiments demonstrated the reduced microhardness of calcium oxalate monohydrate (COM) calculi, relative to dry values, when saturated with an alkaline solution (pH = 9.5). Nineteen patients with a COM calculus in the distal ureter which had been resistant to prior extracorporeal shock wave lithotripsy in situ, were treated when the stone was surrounded by alkaline urine. The urine of 14 patients was alkalinized orally by administration of acetazolamine and citrate solution; in 5 other patients direct percutaneous irrigation of sodium bicarbonate via a nephrostomy tube was carried out. The urinary pH just before lithotripsy was greater than or equal to 9 in 17/19 patients. 4,000 shock waves, averaging 18.1 kV generated by the Siemens Lithostar, were delivered onto the calculus. No significant increase of comminution rate was apparent at radiographic control immediately after the treatment and only in half of the cases was evacuation obtained within 3 months.

Acquired cystic disease of the kidney analyzed by microdissection.

Four cases of acquired cystic disease of the kidney (ACDK) were studied by the microdissection technique (MD) of Darmady and Baert to analyze the cystic transformation. No patient had a history or clinical evidence of the adult polycystic disease of the kidney (APDK). Hypothetical models related the pathogenesis of cystic transformation to either obstructive or degenerative factors. Microdissection was performed in four nephrectomy specimens of hemodialyzed patients and a total of 155 nephrons were isolated. The atrophy of the glomeruli has already been described histopathologically but MD demonstrated the existence of nephrons consisting of sclerotic glomeruli and enlarged segments between the atrophic convoluted proximal and distal tubules. Diverticula and cysts were located, above all along the proximal (mainly dilated) convoluted tubules: they were always in continuity with the tubules. Phase contrast microscopy showed a patent lumen in 80% of the proximal and distal convoluted tubules, and a regular lining of the cysts. These data support the hypothesis that ACDK is the result of hyperplasia and dilation of remaining nephrons, rather than a result of obstruction and/or fibrosis.

Anaesthesia-free extracorporeal shock wave lithotripsy in patients with renal calculi.

Modern extracorporeal shock wave lithotripsy can be performed with combined ECG and respiratory triggered shock wave release. Disconnecting the ECG triggering increases the risk of ventricular arrhythmias, including potentially malignant ones. The aim of this study was to assess the relationship of any sympatho-adrenal excitation as a possible explanation for the occurrence of cardiac arrhythmia. Plasma catecholamine levels were assessed in 5 patients during and after 50 min of anaesthesia-free extracorporeal shock wave lithotripsy for the treatment of calculi in the upper pole of the left kidney. Venous blood sampling showed no significant increase in catecholamines (epinephrine, norepinephrine and dopamine) during or after treatment. The heart rate and arterial blood pressure were measured simultaneously and showed no significant increase when shock waves were released during ECG triggering. However, when disconnecting the ECG-triggering mode, the incidence of ventricular extrasystoles on Holter monitoring became more apparent during respiratory triggered shock wave release only, although there was no rise in plasma catecholamine levels. These data suggest that cardiac arrhythmias are related to direct and accidental mechanical stimulation of the heart rather than to any sympatho-adrenal discharge during shock wave release.

Electromagnetic extracorporeal shock wave lithotripsy in children.

Extracorporeal shock wave lithotripsy (ESWL) was performed for the treatment of urinary tract calculi in 28 children. All treatments were done with the standard Siemens Lithostar device in situ: no special adaptations for adequate positioning of children are required to target the stone precisely. A total of 42 calculi in 30 renal units was treated, requiring 50 ESWL sessions. The mean energy used was 16.4 kv. and the number of shock waves averaged 3,188. Mean fluoroscopy time per session was 1.5 minutes. In 26 of 50 sessions (52%) general anesthesia was needed for the child to remain perfectly still. A complete stone-free rate was achieved in 38 of 42 calculi (90.5%): after 1 session in 30 (71.4%), after 2 sessions in 6 (13.7%) and after 3 sessions in 2 (4.8%). Five staghorn calculi were treated with ESWL monotherapy. A complete stone-free result was obtained after 3 treatments in 2 patients, while 2 had residual fragments in the lower pole (5 mm. after 6 sessions and 11 months of followup in 1, and 7 mm. after 3 sessions and 3 months of followup in 1). A cystine staghorn stone necessitated open nephrolithotomy after 3 sessions without any fragmentation. One impacted sacroiliac ureteral stone required endoscopic laser lithotripsy. Except for these 2 failures no adjuvant procedures were needed. There were no intraoperative or postoperative complications and minor skin bruising at the coupling site after 3 treatments did not require any therapy. We conclude that electromagnetic ESWL with the standard Lithostar unit is a safe and effective method to treat calculi throughout the urinary tract in children.

High energy pulsed dye laser lithotripsy: management of ureteral calcium oxalate monohydrate calculi.

High energy pulsed dye laser lithotripsy (Candela MDL-2000), with energy output upgraded to a maximum of 140 mJ. at the laser fiber tip using the 320 mu core fiber, was compared to the initially commercialized device, with the energy output fixed at 60 mJ. using the 200 mu core fiber (Candela MDL-1). A total of 31 treatments in 28 patients was performed with the Candela MDL-1 device. Complete disintegration or at least fragmentation to spontaneously passable fragments occurred in 18 of 31 cases (58%). Only in 11 of the 24 calcium oxalate monohydrate calculi (46%) was fragmentation achieved. Another 73 laser lithotripsies in 72 patients were performed with the Candela MDL-2000 device. Complete disintegration or at least fragmentation to spontaneously passable fragments was achieved in 67 of 73 treatments (92%). Calcium oxalate monohydrate calculi were successfully treated in 41 of 45 procedures (91%). There was no response to the laser treatment in the only cystine calculus.