Michael Grasso

Experience with the holmium laser as an endoscopic lithotrite

OBJECTIVES To study, in a clinical series, the safety and efficacy of holmium laser energy applied as an endoscopic lithotrite. METHODS Over a 2-year period, patients with urinary tract calculi were treated endoscopically with the holmium laser lithotripter, and data were gathered prospectively. Holmium lasers with maximum outputs of 15, 25, and 60 W were used. Various low water density, quartz fiber delivery systems were developed for specific applications. In addition, various combinations of endoscopes and laser fibers were employed. RESULTS A total of 63 patients with 75 calculi were treated. All calculi were cleared endoscopically. Minimal variation in laser efficiency was noted with different stone compositions, including cystine. Thirty-three of 34 ureteral calculi were treated to completion in one sitting (97%). Twenty-nine renal stone burdens were treated with the holmium laser, 26 of which were treated solely in a retrograde fashion. Of the latter, 23 (88.5%) required only a single sitting. Complications from holmium laser energy, including ureteral stricture disease, were not encountered in this series. Patients with complex, large stone burdens were treated to completion without sequelae. The combination of the actively deflectable, flexible ureteroscope and 200-microns fiber facilitated clearance of 18 lower-pole caliceal calculi. Three patients with partial staghorn stone burdens averaging 30 mm in diameter were treated ureteroscopically. Chronic urinary infections that were problematic preoperatively completely resolved after therapy. All 12 patients who had large bladder calculi with a mean diameter of 55.8 mm were treated to completion in one sitting. CONCLUSIONS Holmium laser energy is uniquely suited to treat all urinary calculi safely and effectively.

RETROGRADE URETEROPYELOSCOPY FOR LOWER POLE CALICEAL CALCULI

PURPOSE Contemporary treatment of lower pole renal calculi includes extracorporeal shock wave lithotripsy, percutaneous nephrostolithotomy and retrograde ureteropyeloscopy. Success rates for shock wave lithotripsy are reduced in this setting, especially for stones greater than 1 cm. and/or in patients with anatomical variants. Percutaneous treatment, although effective, subjects the patient to increased morbidity. We studied the safety and efficacy of retrograde ureteroscopic treatment of lower pole intrarenal calculi. MATERIALS AND METHODS We evaluated 90 stone burdens localized to the lower pole and treated with a small diameter, actively deflectable, flexible ureteropyeloscope and a 200 micron holmium laser fiber. Stone burdens were classified as group 1--10 or less, group 2--11 to 20 and group 3--greater than 20 mm. in largest diameter. Patients with calculi less than 2.5 cm. were treated as outpatients unless concurrent medical conditions required hospitalization. Larger stones and partial staghorn calculi (group 3) frequently required 2-stage endoscopic procedures with retrograde intrarenal irrigation for 36 hours to clear debris. An acceptable immediate surgical outcome was defined as complete fragmentation reducing the stone burden to dust and 2 mm. or less fragments. Success was defined as clear imaging (that is stone-free) on renal sonography with minimum 3-month followup. Extreme anatomical variants, including a long infundibulum, acute infundibulopelvic angle and a dilated collecting system, were noted and correlated with surgical failures. RESULTS Endoscopic access and complete stone fragmentation were achieved in 94, 95 and 45% of groups 1, 2 and 3, respectively. After a second treatment the success rate increased to 82% in group 3, with an overall rate of 91%. Of the 19 surgical failures 8 were secondary to inability to access the lower pole and 11 were secondary to inability to render the patient stone-free. In 2 of the 19 cases infundibular strictures hindered ureteroscopic access. In addition, of the anatomical variants a long lower pole infundibulum was the most statistically significant predictor of failure. Mean operative time ranged from 38 minutes for small to 126 for the largest calculi. There were no major complications. Overall stone-free rates with minimum 3-month followup were 82, 71 and 65% in groups 1, 2 and 3, respectively, and 88, 77 and 81%, respectively, in patients with an acceptable initial surgical outcome (that is excluding those with access failures from analysis). CONCLUSIONS Retrograde ureteropyeloscopy is a safe and effective surgical treatment for lower pole intrarenal calculi.

The case for primary endoscopic management of upper urinary tract calculi: II. Cost and outcome assessment of 112 primary ureteral calculi.

OBJECTIVES To compare extracorporeal shock-wave lithotripsy (ESWL) with endoscopic lithotripsy to establish the more efficacious and cost-effective treatment for ureteral calculi. METHODS The records of 112 patients with primary ureteral calculi treated at one center with either ESWL or endoscopic lithotripsy were retrospectively reviewed. Follow-up data at 1 and 3 months were obtained in all patients. Success was defined as complete clearance of a stone burden in the endoscopy group. In the ESWL group patients with a residual, asymptomatic 2-mm fragment were also considered successful treatments. The number of auxiliary procedures, retreatments, postoperative office visits, and imaging studies required before a patient was considered stone free was defined. The impact of these variables on global costs was carefully reviewed. RESULTS Patients with ureteral calculi primarily treated with ESWL or ureteroscopic lithotripsy had stone-free rates after a single session of 45% versus 95% at 1-month follow-up, and 62% versus 97% at 3-month follow-up. Retreatment and auxiliary procedure rates were significantly higher in the ESWL group (31% versus 3%). The mean number of postoperative visits and imaging studies until a patient was stone free was also higher in the ESWL group (2.07 versus 1.13). Operative treatment costs were similar for both modalities, but overall costs weighed heavily against ESWL. CONCLUSIONS ESWL remains the treatment of choice for moderately sized, uncomplicated renal calculi. In skilled hands, ureteroscopic lithotripsy is by far the most expeditious and cost-effective means of clearing a ureteral stone burden.

The case for primary endoscopic management of upper urinary tract calculi: I. A critical review of 121 extracorporeal shock-wave lithotripsy failures

OBJECTIVES To define those patients with upper urinary tract calculi who are more likely to have an unsuccessful outcome from extracorporeal shock-wave lithotripsy (ESWL). METHODS A critical prospective analysis of 121 patients, referred to two university centers after ESWL had been exhausted as a treatment modality for upper urinary tract calculi, was performed. Patients were subdivided into the following groups: failure to clear fragments, failure to fragment, difficulty in calculus localization, and failure due to inherent upper urinary tract obstruction. Other important variables include the type of extracorporeal lithotriptor used, number of treatment sittings before referral, calculus location, calculus composition, patient body habitus, and the imaging leading to and associated with extracorporeal therapy. RESULTS Large renal calculi (mean, 22.2 mm) and those within dependent or obstructed portions of the collecting system were frequently referred for endoscopic management after failed ESWL. Steinstrasse can be an extremely morbid complication from ESWL and in this series was associated with irreversible loss of renal function and ureteral stricture disease. Extracorporeal lithotripsy of infectious calculi can be associated with severe septic complication. Inadequate preoperative and intraoperative imaging and morbid obesity were also associated with failure. Second- and third-generation lithotriptors were represented in greater numbers than the Dornier HM-3 in this group of ESWL failures. CONCLUSIONS ESWL remains the treatment of choice for moderately sized, uncomplicated renal calculi. Large calculi, those within obstructed or dependent portions of the collecting system, and those composed of calcium oxalate monohydrate, frequently fail ESWL. Training in the more technically challenging aspects of endoscopic lithotripsy must be encouraged.

Ureteropyeloscopic diagnosis and treatment of upper urinary tract urothelial malignancies.

OBJECTIVES To study the application of endoscopic techniques in treating upper urinary tract urothelial malignancies and to define subgroups that may benefit from these therapies. METHODS During a 3-year period, 20 patients with upper urinary tract transitional cell carcinoma were referred specifically for endoscopic therapy. Indications for treatment included a solitary kidney, bilateral disease, modest renal insufficiency, and/or other significant comorbidities. All patients underwent retrograde ureteropyeloscopy. Lesions were biopsied, and lower grade tumors were treated with electrocautery or laser energy. High-grade lesions not amenable to minimally invasive techniques were palliated or treated with standard open surgery. Surveillance was performed at 3 to 4-month intervals by urine cytology and repeat panendoscopy on a similar schedule to lesions of the bladder treated endoscopically. RESULTS Eleven patients (55%) were found to have low-grade, papillary transitional cell carcinoma of the upper urinary tract. Tumors ranged in size from less than 1 cm to filling the entire ureter. All papillary lesions were treated successfully using ureteroscopic techniques without any disease progression. Five small, low-grade recurrences (45%) were defined and treated endoscopically, with a mean follow-up of 17.3 months. Three patients were found at the time of initial diagnostic ureteroscopy to have higher grade lesions and endoscopic treatment was chosen in light of their severe comorbidities. On subsequent imaging, 2 of the 3 patients were suspected of having progression and underwent open surgery, both had carcinoma-in-situ only in the specimen. No tumor progression has been defined in this group to date, with mean follow-up of 16.3 months. A final third group of 6 patients were found to have nonpapillary, high-grade lesions at diagnostic endoscopy and underwent standard surgical resection. The disease of 4 of these 6 patients has progressed with metastases. CONCLUSIONS Papillary, low-grade, low-stage tumors of the upper urinary tract are amenable to endoscopic resection irrespective of size and location. Patients with high-grade lesions defined endoscopically should be offered radical surgery in light of the high rate of disease progression.

RETROGRADE URETEROSCOPIC ENDOPYELOTOMY USING THE HOLMIUM: YAG LASER

PURPOSE We defined the safety and efficacy of retrograde ureteroscopic endopyelotomy using the holmium:YAG laser. METHODS AND MATERIALS Between July 1996 and December 1999 a total of 28 renal units in 21 women and 6 men 7 to 75 years old (mean age 43.5) with ureteropelvic junction obstruction were treated at our institution with retrograde ureteroscopic endopyelotomy. Ureteropelvic junction obstruction was bilateral in 1 case, primary in 20 and secondary in 8. Endoluminal ultrasound was done before endopyelotomy in all cases. Patients with renal calculi underwent antegrade percutaneous nephrostolithotomy and traditional cold knife endopyelotomy. Endoluminal ultrasound revealed posterior and lateral crossing vessels in 5 patients, who did not undergo the endoscopic approach. Retrograde endopyelotomy was performed using the holmium:YAG laser in 23 cases and electrode incision with pure cutting current in 5. Postoperatively a ureteral stent remained indwelling for an average of 6 weeks. Thereafter patients were followed with serial ultrasound, excretory urography and renal scan at 3 to 6-month intervals. RESULTS We evaluated 28 upper urinary tracts, including 19 (67.9%) with high insertion ureteropelvic junction obstruction and 9 with an annular stricture. As directed by ultrasound images, the incision location was posterolateral, posterior, lateral and posteromedial in 16, 5, 4 and 3 cases, respectively. Followup was available in all cases at a mean of 10 months (range 3 to 35). Success, defined as improved drainage on radiographic study and absent clinical symptoms, was achieved in 19 of the 23 patients (83%) treated with the holmium:YAG laser. Repeat laser incision resulted in a successful outcome in 2 of the 4 treatment failures. There were no acute surgical complications. CONCLUSIONS Retrograde ureteroscopic endopyelotomy with the holmium:YAG laser is safe and minimally invasive therapy for primary and secondary ureteropelvic junction obstruction. Endoluminal ultrasound aids in decision making when retrograde endopyelotomy is done.

SUPERSATURATION AND STONE COMPOSITION IN A NETWORK OF DISPERSED TREATMENT SITES

PURPOSE We determined the validity of urine supersaturation assessed from 2, 24-hour urine collections from outpatients eating uncontrolled diets and receiving care at a network of treatment sites that uses a central laboratory. We compared supersaturation to stone composition to determine whether supersaturation values correlate with composition. MATERIALS AND METHODS Two 24-hour urine samples collected from 183 patients at 6 treatment sites were shipped to a single central laboratory. Complexations and crystallizations in vitro from aging during the transport step were interrupted by pH change in acid and alkaline directions. Relevant analytes were measured, and supersaturation was calculated for calcium oxalate, calcium phosphate as brushite and uric acid. Stone analysis was done at various laboratories. RESULTS Urine supersaturation values correlated well with stone composition. Higher calcium phosphate and uric acid supersaturation was noted when stones contained higher amounts of calcium phosphate and any uric acid, respectively. In a validation study values of relevant urine materials were unchanged after 48 hours of aging. CONCLUSIONS Despite the need for sample transport, resulting in the inevitable aging of samples, and variations in diet and details of sample collection, supersaturation values measured in only 2, 24-hour urine collections accurately reflected stone composition. This finding indicates that supersaturation values are reasonably stable in most patients during the months to years required for stones to form. In addition, samples collected in standard practice settings and sent to a central laboratory may accurately reflect these supersaturation values.

MEDICAL REDUCTION OF STONE RISK IN A NETWORK OF TREATMENT CENTERS COMPARED TO A RESEARCH CLINIC

PURPOSE We determined whether a network of 7 comprehensive kidney stone treatment centers supported by specialized stone management software and laboratory resources could achieve reductions in urine supersaturation comparable to those in a single research clinic devoted to metabolic stone prevention. MATERIALS AND METHODS Supersaturation values for calcium oxalate, calcium phosphate and uric acid in 24-hour urine samples were calculated from a set of kidney stone risk factor measurements made at a central laboratory site for the network and research laboratory for the clinic. Individual results and group outcomes were presented to each center in time sequential table graphics. The decrease in supersaturation with treatment was compared in the network and clinic using analysis of variance. RESULTS Supersaturation was effectively reduced in the network and clinic, and the reduction was proportional to the initial supersaturation value and increase in urine volume. The clinic achieved a greater supersaturation reduction, higher fraction of patient followup and greater increase in urine volume but the treatment effects in the network were, nevertheless, substantial and significant. CONCLUSIONS Given proper software and laboratory support, a network of treatment centers can rival but not quite match results in a dedicated metabolic stone research and prevention clinic. Therefore, large scale stone prevention in a network system appears feasible and effective.

Divergence between stone composition and urine supersaturation: clinical and laboratory implications.

PURPOSE In general high urine supersaturation with respect to calcium oxalate, calcium phosphate or uric acid is associated with that phase in stones. We explore the exceptions when supersaturation is high and a corresponding solid phase is absent (type 1), and when the solid phase is present but supersaturation is absent or low (type 2). MATERIALS AND METHODS Urine supersaturation values for calcium oxalate, calcium phosphate and uric acid, and other accepted stone risk factors were measured in 538 patients at a research clinic and 178 at stone prevention sites in a network served by a single laboratory. RESULTS Of the patients 14% lacked high supersaturation for the main stone constituent (type 2 structural divergence) because of high urine volume and low calcium excretion, perhaps from changes in diet and fluid intake prompted by stones. Higher calcium excretion and low urine volume caused type 1 divergences, which posed no clinical concern. CONCLUSIONS Type 1 divergence appears to represent a condition of low urine volume which raises supersaturation in general. Almost all of these patients are calcium oxalate stone formers with the expected high supersaturation with calcium oxalate as well as high uric acid and calcium phosphate supersaturations without either phase in stones. Type 2 divergence appears to represent an increase in urine volume and decrease in urine calcium excretion between stone formation and urine testing.

Stone granuloma causes ureteropelvic junction obstruction after percutaneous nephrolithotomy and antegrade endopyelotomy

Stone granuloma is a rare cause of ureteral obstruction. To our knowledge only 1 case of secondary ureteropelvic junction obstruction following percutaneous nephrolithotomy and ultrasonic lithotripsy has been reported in the literature. It has been postulated that perforation with migration of stone fragments into the ureteral wall may be a mechanism for this occurrence. We report a case of recurrent ureteropelvic junction obstruction due to stone granuloma after simultaneous percutaneous nephrolithotomy and antegrade cold knife endopyelotomy.