Can ureteral stent encrustation analysis predict urinary stone composition?

OBJECTIVES

To determine the value of mid-infrared spectroscopy (MIRS) of ureteral stent encrustations in predicting urinary stone composition.

METHODS

A retrospective study analyzed the composition of stent encrustations and urinary stones by MIRS in patients who had had a stent for ureteral obstruction between 2001 and 2003. The overall correlation was evaluated. The correlation coefficient kappa for agreement between the proportions of each component was calculated.

RESULTS

A total of 72 stents and 72 stones from 72 patients were analyzed. The mean stent indwelling time was 55.5 days (range 14 to 102). The stents had been placed for fever (52 cases, 72%), pain refractory to analgesics (15 cases, 21%), and impairment of kidney function (5 cases, 7%). The overall correlation between stone composition and stent encrustation was 71.4%, excluding biofilm analysis. The kappa value was 0.78 for the main component (n = 72; P < 0.0005), 0.61 for the secondary component (n = 72; P < 0.0005), and 0.91 for the agreement between the composition of encrustations at each end of a stent (n = 30; P < 0.0005).

CONCLUSIONS

MIRS analysis of stent encrustations is a reliable method of predicting stone composition when the stone cannot be retrieved. Systematic MIRS analysis of stent encrustations is not recommended but can be very useful in clinical situations in which no stone is available.

[Silica-containing urinary stones--clinical issues to keep in mind]

Formation of calculi in efferent urinary passages is always due to supersaturation of urinary calculi substances and associated increased crystallization. Apart from the typical calculi, consisting of calcium oxalate, inorganic phosphates, uric acid or cystine, there are occasional signs of rare substance classes. Although more than 50 silicate stones have already been reported internationally, this stone entity remains relatively unknown. In particular, the occurrence of silicate stones in the absence of magnesium trisilicate abuse is extremely rare. A medium-sized left-sided ureterolith was removed from a 54-year-old male patient using a ureteroscope. X-ray diffraction showed it to be a compound stone consisting of 40% silicate. The patient, who in 1986 was living close to the nuclear reactor accident in Chernobyl, showed no signs of a constant uptake of magnesium trisilicate. However, he had undergone partial (2/3) gastrectomy 4 months before for a drug-refractory gastric ulcer, which had been diagnosed at the end of the 1980s and treated with excessive dosages of a magnesium trisilicate antacid preparation until the time of the operation. The patient had also been suffering from unstable angina pectoris since 1986 and treated with Pentalong (pentaerythrityltetranitrate) for 17 years. We were also able to detect silicium dioxide in components of this drug using X-ray diffraction. Silicate uroliths are extremely rare but they can be clearly identified by X-ray diffraction or infrared spectroscopy and distinguished from artifacts or quartz pebbles. Formation of calculi can be prevented by increasing diuresis as well as switching to a different drug and reducing the dosage.

Stone disease in the Hmong of Minnesota: initial description of a high-risk population

BACKGROUND AND PURPOSE

The Hmong are an ethically distinct refugee population from the highlands of Laos. Metropolitan Minneapolis-St. Paul, Minnesota is home to the largest population of Hmong ( 40,000) outside Asia. A clinical impression that the Hmong have a high rate of uric acid stone disease was evaluated.

PATIENTS AND METHODS

A retrospective chart review was performed. All adult Hmong patients seen between January 1, 2000, and December 31, 2001, by a large urology group practice (N = 205) were compared with a similar number of non-Hmong patients (N = 204).

RESULTS

Of these patients, 94 Hmong (46%) and 23 non-Hmong (11%) patients had stone disease (P < 0.001). After addition of 75 non-Hmong stone patients to create a suitable comparison group, a total of 86 Hmong and 88 non-Hmong stone patients had complete records. Sex (57% v 60% male) and mean age (47.9 v 47.3 years) were similar. Staghorn calculi were found in 21 Hmong (24%) and 0 non-Hmong patients (P < 0.001). Surgical treatments differed between Hmong and non-Hmong (P = 0.004): SWL (16 v 35), ureteroscopy (24 v 29), percutaneous nephrolithotomy (19 v 7), and nephrectomy (5 v 0). Treatment for staghorn calculi was refused by 9 Hmong patients (43%). Stone composition was available in 40 Hmong and 39 non-Hmong. Uric acid (>10%) was found in 50% of Hmong and 10% of non-Hmong stones (P < 0.001).

CONCLUSIONS

Hmong patients who come to urologic attention tend to do so for stone disease and tend to have uric acid calculi. The frequent requirement for invasive therapy, including nephrectomy, in the Hmong is of concern.

Evaluation of a synchronous twin-pulse technique for shock wave lithotripsy: the first prospective clinical study

OBJECTIVE

To present the results of the first clinical study of a synchronous twin-pulse technique for extracorporeal shock-wave lithotripsy (ESWL), which is effective for in vitro stone fragmentation and safe when assessed in vivo on animal tissue.

PATIENTS AND METHODS

Fifty patients with urinary stones (35 men and 15 women) were enrolled and treated with the TWINHEADS lithotripter. The entry criteria were: age > or = 18 years, with a radio-opaque single stone in the kidney or upper ureter, a normal laboratory profile (serum creatinine, liver function, blood, bleeding and clotting times, and prothrombin concentration). The exclusion criteria included lower ureteric stones, patients with urinary tract infection, obstructed urinary tract distal to the stones, or congenital abnormalities. All patients received one session and were evaluated by ultrasonography (US), urinary tract plain X-ray, and complete laboratory investigations before and immediately after treatment, and after 2, 14 and 30 days. Patients requiring re-treatment at the 14-day visit received a second session and were re-evaluated after 7 and 14 days.

RESULTS

The mean (sd, range) stone size (longest diameter) was 12.3 (2.6, 9-18) mm. Intravenous sedation was used in 30 patients. There was mild haematuria in 25 patients on the day of treatment. During the follow-up there was no evidence of haematoma, gross renal injury, upper urinary tract obstruction or significant changes in the laboratory investigations. After 14 days, 17 patients (34%) were free of stones, with residual stones of < or = 5 mm in 20 (40%); they were free of stones at the 1-month follow-up. Thirteen patients (26%) had residual stones of 6-9 mm, but the stones were half or less of the original size. Patients with residual stones of > 5 mm had another ESWL session and were free of stones within 14 days. Thus all patients were rendered stone-free within 1 month.

CONCLUSIONS

Synchronous twin-pulse ESWL is promising, seems safe and effective for treating patients with renal and upper ureteric lithiasis.

Dissolution of ureteral uric acid calculi with local litholytic irrigation

This study was designed to evaluate the efficacy of local litholytic irrigation (LLI) in the treatment of ureteral uric acid calculi. Fourteen cases of ureteral uric acid calculi were diagnosed by abdominal plain radiography (KUB), retrograde urography, ultrasonography (B-mode ultrasound), spiral computerized tomography(CT) and blood biochemical examinations. A ureteral catheter was passed retrogradely across ureteral calculi by cystoscopy. LLI with tromethamine-E (THAM-E) was performed via the ureteral catheter after the improvement of renal function and general situation and the control of urinary tract infection under the condition of intravenous application of antibiotics. The irrigation rate varied from 1000 to 1500 ml per day. Retrograde pyelography demonstrated complete dissolution of all the stones, 13 cases within 10 days and 1 within 12 days. Mild hematuria was observed in the majority of the cases and temporary aggravated lumbago in 1 case, with no other side effects. It is concluded that LLI is a practical and effective method in the treatment of ureteral uric acid calculi for its advantages of shorter duration,lower cost, less physical suffering and no severe complications.

Ureteroscopy for pediatric urolithiasis: An evolving first-line therapy

OBJECTIVES

To present in a retrospective report a contemporary series of patients aged 14 years and younger who were treated for stones with ureteroscopy at our institution from 1991 to 2002. With the improvement and miniaturization of ureteroscopes and ancillary instruments, the endoscopic treatment of renal and ureteral calculi in children has become more feasible.

METHODS

A retrospective chart review was performed of 23 patients aged 14 years and younger who had undergone ureteroscopy for the treatment of ureteral or renal calculi at our institution.

RESULTS

A total of 27 stones were treated in 23 patients. Of the 27 stones, 18 were in the distal ureter, 5 in the mid ureter, 2 in the proximal ureter, and 2 in the renal pelvis. Ureteral dilation was performed in 4 (17.4%) of the 23 patients. The lithotripsy modalities used were holmium:yttrium-aluminum-garnet laser in 16 (69.6%), electrohydraulic lithotripsy in 3 (13%), a combination of holmium laser and electrohydraulic lithotripsy in 2 (8.7%), and basket extraction alone in 2 (8.7%) of 23 patients. Ureteral stents were placed in 21 (91.3%) of 23 patients. The average operative time was 46.9 minutes (range 15 to 92). In 21 (91.3%) of 23 patients, postoperative imaging was available and revealed that 20 (95.2%) of the 21 patients were rendered stone free. Two patients were lost to follow-up. No intraoperative complications occurred. One patient was treated postoperatively with intravenous antibiotics for transient fever.

CONCLUSIONS

Ureteroscopy is safe and effective in the management of ureteral and renal calculi in children. In our institution, it has emerged as a valid first-line therapy for the treatment of pediatric urolithiasis.

[Ammonium acid urate stone due to laxative abuse: a case report]

We report a case of ammonium acid urate stone due to laxative abuse. A 27-year-old female complained of left flank pain. Computed tomography revealed bilateral ureter stones (right 16.5 x 9.0 mm; left 4 mm), while left ureter stone was radiolucent on the plain X ray film. Bilateral hydronephrosis was seen, but no therapy was performed for the right stone, because 99mTc-MAG3 scintigraphy revealed that right kidney had no function. The left stone was successfully removed by transurethral approach. The stone was revealed to be an ammonium acid urate by infrared spectrophotometry. She had been taking many laxatives (bisacodyl, sennoside, aloe extract) for 12 years to control her body weight. Ammonium acid urate stones are rarely seen in developed countries. We have reviewed 9 cases in Japan, describing ammonium acid urate stones due to laxative abuse. Among these patients, 24-hour urine volume and excretion in urinary sodium were decreased, and serum aldosterone was increased. The involvement of laxative abuse should be considered when ammonium acid urate is formed in a woman with a low body mass index.

Stone fragility: its therapeutic implications in shock wave lithotripsy of upper urinary tract stones

OBJECTIVE

To analyse the impact of stone composition on stone fragility (fragmentation) and clearance of upper urinary tract stones after shock wave lithotripsy (SWL).

MATERIAL AND METHODS

Between 1st July 1998 and 31st July 2001, 300 renal and ureteric units of 290 patients (10 being bilateral) underwent SWL for upper urinary tract calculi. The degree of fragmentation was divided into four types: (I) Excellent, (II) Good, (III) Fair and (IV) No fragmentation. Stone composition was done by X-ray diffraction crystallography. A statistical comparison was made between degree of fragmentation, number of shock waves delivered, voltage setting, number of sessions required and requirements of adjuvant procedures according to the stone composition.

RESULTS

Stone analysis revealed that 90% of the patients had calcium oxalate stones. Of these 80% were calcium oxalate monohydrate (COM) and 20% calcium oxalate dehydrate (COD). Struvite, apatite and uric acid stones comprised of 6%, 3% and 1% respectively. Type-I fragmentation was achieved up to 63.96%, 50% and 100% in COD, struvite and uric stones respectively as compared to 44.9% and 44.44% for COM and apatite stones. Type-III fragmentation was seen up to 8.79% and 33.3% respectively in COM and apatite as compared to 5.55% or less in other types of the stones suggesting that COM and apatite stones produce larger fragments. The mean number of shock waves, voltage and number of treatments was significantly higher for COM and apatite stones (p value < 0.005) with a stone free rate of only 65-66% and 65-68% respectively at three months (p value < 0.001). Similarly the number of adjuvant procedures required in COM alone was more, i.e. 31 as compared to 17 procedures in rest of the other kinds of stones (p value < 0.05).

CONCLUSION

Stone composition in Indian subcontinent is different from the western world. Fragility of a stone varies with the composition of the stone and affects the therapeutic results.

Bilateral guaifenesin ureteral calculi

We report on a patient with bilateral ureteral calculi composed of guaifenesin metabolite as determined by infrared spectroscopy. These stones may be associated with excessive guaifenesin intake related to the current popularity of ephedrine preparations.

[Extracorporeal shockwave lithotripsy in the treatment of distal ureteral stones larger than 10 mm in diameter]

Optimal treatment for distal ureteral stones remains controversial. During a period of 10 years, from December 1992 to December 2002, 103 distal ureteral stones larger than 10 mm in diameter were treated at our institution with extracorporeal shock wave lithotripsy (ESWL) using the Siemens Lithostar. Only 2 patients had a ureteral stent in place at the time of treatment. The overall stone-free rate was 98% with 1-12 session and 3-month stone-free rate was 95.1%. These data reveal that a high success rate was achieved in multisession ESWL. Therefore, ESWL is considered to be acceptable as first-line therapy for fragmentation of distal ureteral stones larger than 10 mm in diameter.

[The clinical significance of 50 cases of percutaneous nephroureteral lithotripsy]

Percutaneous nephroureteral lithotripsy (PNL) was conducted in 50 patients with renal or ureteral calculi between March 2000 and August 2002. The mean age of patients was 56.6 years (range 25-82 years) and they included 29 males (58.0%) and 21 females (42.0%). The calculi were renal calculi in 38 patients (76.0%) and ureteral calculi in 12 patients (24.0%). The mean number of calculi was 1.5 (1-10 calculi, median number 1). The mean of the maximum calcule diameter was 30.9 mm (15.0-83.0 mm) for the renal calculi and 17.4 mm (8.0-27.0 mm for the ureteral calculi. The lithotripsy device was an ultrasonic lithotriptor (ALOKA) or Lithoclast (SWISS), as appropriate, and was used with a 24 Fr rigid endoscope (TAKEI). All operations were performed under lumbar spinal anesthesia. Eighteen of the 38 renal calculus patients were treated with PNL alone. In the other 19 PNL was combined with postoperative extracorporeal shock wave lithotripsy (ESWL). Seven of the 12 patients with ureteral calculi were treated with PNL alone, and 5 with PNL combined with postoperative ESWL. After 3 months, the treatment results were Tx(3)-0 in 45 patients (90.0%), and Tx(3)-2 in 5 patients (10.0%). The mean period of postoperative hospitalization was 30.3 days (10-86 days), with a median of 26 days. Complications were renal pelvis perforation in 1 patients and fever of 38.0 degrees C or above in 16 patients, but there was no hemorrhaging that required transfusion or other serious complications. PNL is a safe and reliable treatment method, and should be considered as a treatment option in cases of large calculi when a short treatment period is desired.

Endoscopic management of milk of calcium-filled ureterocele stump

A 38-year-old woman with a duplicated right collecting system and a history of right upper-pole heminephrectomy was referred for persistent dysuria and right lower-quadrant abdominal discomfort. Imaging identified a remnant ureter and a ureterocele filled with what appeared to be a large homogenous stone. At cystoscopy, the ureterocele was incised with a holmium:YAG laser, releasing a large quantity of white milky fluid (milk of calcium). There was no evidence of any solid material. Endoscopic evaluation should be the first step in patients with stones in a ureteral stump because milk of calcium may be the etiology of what appears to be a large stone burden in an obstructed system.

Extracorporeal shock wave lithotripsy for cystine urolithiasis in children: outcome and complications

The Siemens Lithostar Litotriptor was used to treat 6 children with cystine nephrolithiasis, previously treated by open surgery. Five children had renal calculi (3 multiple caliceal, 2 pelvis) and one had ureteral calculus. Stone size ranged from 0.2-2.5 cm in diameter, and stone burden was from 0.24 to 10.81 cm3 per kidney. From one to 4 ESWL sessions per unit were applied, with a total of 1,800 to 12,000 shock waves. The stone free rate at 3 months was 50%. A complete elimination was obtained with cystine stones in renal pelvis and ureter, however, up to 4 ESWL treatments failed in caliceal stones. Rather location of cystine calculi than previous surgery was associated with ESWL success rate. Two patients with positive urine cultures were successfully treated with appropriate antibiotics before ESWL was attempted. Perirenal hematoma was major complication demonstrated by radionuclide scintigraphy in one patient, and resolved spontaneously by 3 months. In the combined treatment of cystine urolithiasis in children ESWL, as auxillary procedure, was safe and effective in pelvis stone but failed in caliceal stones. Medical dissolution for retained fragments was found effective.

Obstructive nephropathy secondary to sulfasalazine calculi

The incidence of drug-induced stone disease is 0.44%. A 57-year-old woman with ulcerative colitis presented with obstructive nephropathy and pyelonephritis. She underwent cystoscopy, bilateral retrograde pyelography, and bilateral ureteral stent placement. A 6-cm bladder calculus and two 3-mm right distal ureteral calculi were discovered. Later, cystolithotomy was performed. The stone analysis demonstrated sulfapyridine, a sulfasalazine metabolite. Patients with inflammatory bowel disease can develop urolithiasis owing to acidic urine and low-volume urine production. Patients receiving aminosalicylates are at an increased risk of urolithiasis and may benefit from oral hydration and urinary alkalization.

University of Wisconsin experience using the Doli S lithotriptor

OBJECTIVES

To present our initial results using the Dornier Doli S lithotriptor with the 220 electromagnetic shock wave emitter to treat urinary calculi. At present, there is no published report of the efficacy of this instrument in service in the United States.

METHODS

We retrospectively reviewed the outcome of shock wave lithotripsy in 270 consecutive patients with solitary renal and/or ureteral stones treated from September 1998 to October 2001 with the Dornier Doli S lithotriptor. Data were collected with respect to stone size, location, and fragmentation.

RESULTS

Of the 270 patients treated, 204 had renal stones and 66 had ureteral stones. All patients had solitary stones. The renal stones averaged 9.7 mm in size (range 4 to 26). The ureteral stones averaged 7.8 mm (range 4 to 17). Of the renal stones, 51% were located in the renal pelvis, with 18%, 5%, and 25% located in the upper, middle, and lower poles, respectively. Of the ureteral stones, 68% were located in the proximal ureter, with 14% and 18% in the mid and distal ureter, respectively. In the renal group, 176 (86%) of 204 patients achieved clinical success. Of these patients, 148 were stone free (73%) and 28 had residual fragments less than 4 mm in size (14%). In the ureteral group, 52 (79%) of 66 patients achieved clinical success. Of these patients, 50 were stone free (76%) and 2 (3%) patients had fragments less than 4 mm in size. Thirteen (6%) of 204 patients in the renal group required retreatment. Four (6%) of 62 patients in the ureteral group required retreatment. Of the patients in whom treatment failed and who had stone analysis, 16 (76%) of 21 had stones composed of predominantly calcium oxalate monohydrate. Four patients developed steinstrasse. Two were treated with retrograde stent placement, and the other two with placement of percutaneous nephrostomy. One patient developed a known perinephric hematoma but did not require a blood transfusion.

CONCLUSIONS

Shock wave lithotripsy using the Doli S in appropriately selected patients is an effective instrument for treating urinary calculi throughout the urinary tract.

[2,8-dihydoroxyadenine (DHA) urolithiasis: a case report]

We report a case of 2,8-dihydroxyadenine (DHA) urolithiasis in a 28-year old female. She was admitted to our hospital complaining of a sudden pain in the left lumbar region. Abdominal X-ray (kidney-ureter-bladder; KUB) and computed tomography (CT) demonstrated a radiolucent left ureteral (8 x 6 mm2) and a renal (15 x 10 mm2) stone. In the repetitive procedure of transurethral ureterolithothripsy (TUL) and extracorporeal shock wave lithotripsy (ESWL), the stones had been removed successfully. The spectrophotometric analysis of the stone fragments revealed an absorption spectrum for 2,8-DHA. Adenine phosphoribosyltransferase (APRT) enzyme activity was lowered to 0.8 nmol/hr/mg protein. Thus, we diagnosed the illness as 2,8-DHA urolithiasis originating from APRT deficiency. A molecular analysis of the APRT gene by the polymerase chain reaction (PCR) method revealed the genotype to be APRT*J/APRT*Q0.

[Urologic interventional therapy of kidney calculi (I)--extracorporeal shockwave lithotripsy]

With a prevalence of around 5% in western countries, urolithiasis is a frequently occurring disease but with a poorly understood pathogenesis. Effective prevention is not possible for most stone types, in particular for calcium-containing stones, which occur most frequently. Additionally, after occurrence, patient compliance is often inadequate. Interventional therapy becomes necessary after stone manifestation within the urinary tract. Not all stone compositions respond to a drug treatment. Whereas in the seventies, stone treatment meant open surgery newly developed minimally-invasive procedures have displaced this treatment. The clinical introduction of extracorporal shock wave lithotripsy (ESWL) has played a crucial role in this process. Today, more than 80% of all urinary stones can be treated by modern lithotripters. Combination with other minimally-invasive procedures further improve stone free rate. This article provides an overview of technique, application and results of ESWL treatment.

Clinical association with urinary glycosaminoglycans and urolithiasis

OBJECTIVES

To determine the clinical association between urinary glycosaminoglycan (GAG) concentration and kidney stone disease.

METHODS

Thirty-five patients (14 women and 21 men) with a history of stone disease and 37 controls (13 women and 24 men) were evaluated for urinary GAG concentration. By using a new dye-binding assay, the total GAG concentration in the urine was measured and corrected to urinary creatinine levels (micrograms of GAG per milligram creatinine).

RESULTS

The mean urinary GAG concentration in those with stones was significantly lower (31.5 +/- 2.6 microg GAG/mg creatinine) than in the controls (43.8 +/- 3.8 microg GAG/mg creatinine, P = 0.01). Male patients with stones also had a significantly lower mean GAG concentration (26.1 +/- 1.8) than did the female patients (39.6 +/- 5.3, P = 0.009). The mean GAG concentration between ureteral (n = 13) versus renal (n = 22), single (n = 19) versus multiple (n = 16), family history (n = 11) versus no family history (n = 24), large (n = 13) versus small (n = 20), and the presence (n = 22) versus absence (n = 13) of residual stones did not show any significant differences. However, patients with recurrent stone formation (n = 21) had significantly lower mean GAG levels (26.4 +/- 1.6) compared with those with single stone formation (n = 14; 39.2 +/- 5.5, P = 0.01).

CONCLUSIONS

Lower urinary GAG levels are more common in patients with stone formation. This may play a more determinant role in male patients and those with recurrent stone formation.

Utility of oral dissolution therapy in the management of referred patients with secondarily treated uric acid stones

OBJECTIVES

Uric acid stones are best managed by chemolysis. Some patients with acutely symptomatic stones opt for endourologic therapies. The radiolucent nature of these stones makes secondary interventions difficult to plan. Computed tomography becomes the modality of choice to identify stone locations and size in these patients. We analyzed patients with uric acid stones referred to our stone center after primary treatment had failed to establish the efficacy of oral alkalinization therapy.

METHODS

Eleven patients presented after one or more failed attempts to intervene for uric acid stones. Charts were reviewed for age, sex, time with stone before referral, medical therapies undertaken, number of antecedent urologic interventions, number of radiographic studies performed, subsequent procedures performed, and outcomes with a minimal follow-up of 6 months.

RESULTS

Eight patients were men and four presented with bilateral stone disease (overall, 15 involved upper tracts). Sixty-seven percent of patients had right-sided solitary calculi. All patients at presentation filled out urinary pH diaries. Of the 11 patients, 4 stated they had been prescribed oral alkaline therapy but were found to be noncompliant, 4 were never prescribed this therapy, and 3 took the medication sporadically. All patients were counseled on self-dosing to maintain their urinary pH between 6.0 and 6.5 and to continue the diaries. Computed tomography scans were done in 9 patients, and intravenous urography and ultrasonography in the other 2 patients confirmed the stone burden. Only 3 patients (27%) required subsequent interventions (ureteroscopic laser lithotripsy).

CONCLUSIONS

Secondarily referred patients with uric acid stones are best treated with medical therapy. These findings suggest that the initial medical regimens had failed because of noncompliance or lack of effective follow-up by the primary urologist. Seventy-three percent of these patients had dissolution of the stones, requiring no further endourologic intervention.

Impact of power index, hydroureteronephrosis, stone size, and composition on the efficacy of in situ boosted ESWL for primary proximal ureteral calculi

OBJECTIVES

The efficacy, safety, feasibility, and outcome of in situ treatment applied to select proximal ureteral calculi was assessed and analyzed with a view to avoiding auxiliary interventions and providing high clearance rates in the shortest possible time. We studied the impact of several clinically important variables, including power index, degree of hydroureteronephrosis (HDUN), stone size, and composition on the efficacy of sequential in situ boosted extracorporeal shock wave lithotripsy (ESWL) in a select group. The power index requirement for the in situ boosted protocol and the impact of the stone size/composition, degree of HDUN, and clearance rates were also analyzed.

METHODS

An in situ (no instrumentation) boosted protocol was applied to 130 primary unimpacted proximal ureteral calculi with no prior intervention. A typical session with the Siemens Lithostar Plus comprised 3000 shock waves, in installments of 500, deployed at a power setting of 1 to 4 kV with a gradual stepwise escalation. Sequential boosted additional sessions of ESWL were administered on days 2, 7, and 14, tailored to the degree of fragmentation, clearance status, and amount of residual stone bulk. Several parameters (shock waves, kilovolts used, fluoroscopy time, number of sessions, stone size, composition, fragmentation, clearance, and HDUN) were recorded and the results analyzed statistically.

RESULTS

The results were excellent in 83.8%, with a mean duration to complete clearance of 11.3 days. In situ ESWL failed in 7.69%, and the auxiliary intervention rate was 10.7%. Pre-ESWL HDUN was present in 78.3%, the mean power index was 184.6/session/case, and the average stone burden was 8.9 mm(2). Calcium oxalate monohydrate was the most common stone (56%). Renal colic was the most common side effect observed. The power index, fragmentation at the first session, and stone size were found to be the most favorable significant variables affecting stone clearance. The degree of HDUN, number of sessions, and stone composition did not significantly impact the clearance rates.

CONCLUSIONS

In situ boosted ESWL should be the first-line therapeutic modality in select unimpacted primary proximal ureteral stones.

Current evaluation and management of renal and ureteral stones

A systematic clinical approach is required for the diagnosis and management of renal and ureteral stones. The presenting symptoms, past medical history, medications, and physical examination all provide clues to the diagnosis of urinary stones. In the acute setting, noncontrast helical computerized tomography has emerged as the first line imaging test for renal colic. More traditional imaging tests are also important in the management of stone disease. After making the diagnosis of a urinary stone, the urologist should discuss the advantages and disadvantages of all treatment options with the patient. For most stone patients today, many equally effective treatment approaches can exist for the same problem. To help direct surgical management, guidelines for stone management have been devised. With technologic advances, stone treatment has improved and complications have decreased. While patient care has been significantly impacted by use of effective endourologic techniques, patients should complete imaging tests following surgery to assure a stone-free state. In addition, recurrent stone formers should complete a medical stone evaluation to identify treatable causes of their stones.

Transurethral ureterolithotomy in 100 lower ureteral stones

A total of 100 patients with lower ureter stones received transurethral ureterolithotripsy (TUL) using a pulsed dye laser and/or a pneumatic lithotriptor. Extracorporeal shock wave lithotripsy treatment was added in 15 patients because fragments larger than 4 mm had been pushed back to the renal pelvis. The median stone size was 8 mm (range 3-22 mm). Operative time ranged between 3 and 157 min with a median of 30 min. Stone size correlated well with impaction, when impaction was defined as the inability of a guidewire to pass over the stone. Complete removal was defined as total clearance at 1 month without retreatment. The overall stone-free rate was 93%. Among the 7 not-stone-free cases, 5 cases were considered to have been treated successfully because asymptomatic residual fragments were smaller than 4 mm, 1 case required retreatment to become stone free, and 1 case with a silent residual fragment of 8 mm had been followed up for 3 months. The success rate was 98% when successful treatment was defined as total clearance or the presence of asymptomatic residual fragments of 4 mm or less without retreatment. Impaction was not a significant determining factor of stone-free rate (95.7 and 86.7%, respectively, p > 0.05) and in situ stone-free rate (TUL alone; 85.7 and 76.7%, respectively, p > 0.05). Two minor ureteral perforations were encountered. No patient required percutaneous nephrostomy or open surgery, or showed any late complications. TUL is a safe and successful method in managing lower ureteral stones.