Robert C. Newman

Pathologic effects of ESWL on canine renal tissue

The introduction of extracorporeal shock wave lithotripsy (ESWL) has provided an avenue for dealing with many urinary stones noninvasively. The margin of safety for the kidney during shock wave administration is largely undefined. A pilot study was performed where six kidneys in five female mongrel dogs were shocked. Group A kidneys were given 1,776, 4,500, 6,000, or 8,000 shocks, respectively, at 18-24 kV. Group B kidneys received 1,600 and 8,000 shocks (18-24 kV). The number of shocks per electrode ranged from 500 to 4,538 and averaged 2,490. The dogs were sacrificed forty-eight to seventy-two hours (Group A) or twenty-eight to thirty-two days (Group B) post-treatment. Modest damage (hematoma and/or interstitial hemorrhage) was noted in all kidneys. Evidence of permanent change (fibrosis) was noted in both Group B kidneys. Complete necrosis of the kidney was not seen after administration of 8,000 shocks. These preliminary data indicate that lithotripsy can, in some circumstances, produce renal damage in the canine model.

Treatment of Pediatric Urolithiasis Between 1984 and 1994

PURPOSE We report our experience with the management of pediatric urolithiasis during a 10-year period. Our aim was to assess the impact of new technology in the treatment of pediatric urolithiasis. MATERIALS AND METHODS We retrospectively reviewed the records of all patients up to age 18 years in whom urolithiasis was treated from 1984 to 1994. In 37 cases 24-hour urine collections were available for metabolic evaluation. RESULTS A total of 100 pediatric patients was treated for urolithiasis. Mean followup was 36 months. A total of 79 patients underwent 115 procedures for symptomatic urolithiasis and 21 were treated nonoperatively. In 42 patients structural anomalies of the urinary tract required additional management. Metabolic abnormalities in 48 patients included hypercalciuria in 19, defined as greater than 4 mg./kg./24 hours calcium by 24-hour urine collection. Only 24 of the 100 patients had no identifiable predisposing factors. Procedures included shock wave lithotripsy in 42 cases, basket extraction with or without ureteroscopy in 20, percutaneous nephrostolithotomy in 11 and litholapaxy in 12. Open surgery included cystolithotomy in 10 cases and other forms of open lithotomy in 15. Thus, open surgical removal was necessary in 1 of 5 cases. CONCLUSIONS Compared to the traditional mode of stone treatment, fewer patients required open surgery. Our results indicate that a comprehensive approach to the care of pediatric patients with urolithiasis requires attention to metabolic and structural abnormalities.

Extracorporeal shock-wave lithotripsyin horseshoe kidneys

Abstract Using the Dornier HM-3 lithotriptor, 10 patients (11 renal units) with calculi in horseshoe kidneys were treated with extraeorporeal shock-wave lithotripsy (ESWL) and ancillary procedures. Six renal units (55 %) underwent pre-ESWL manipulation consisting of a Double J stent, ureteral catheter, or percutaneous nephrostomy. The “blast path” was employed to treat five renal units which could not be positioned at F2. Good initial stone fragmentation was obtained in eight renal units (73 %). There were two episodes of post-ESWL obstruction requiring intervention; both occurred in the same patient. A total of seven post-ESWL procedures were performed on two renal units. After all procedures, eight renal units (73 %) were rendered stone: free, six (55 %) with ESWL alone. The average follow-up interval was twelve months (range 1–28 months). ESWL can be used effectively to treat some patients with calculi in horseshoe kidneys. The ectopic location of these renal units may make it difficult to position calculi at F2, thus necessitating treatment on the blast path or placement of the patient in prone position. Multiple ancillary procedures may be necessary.

Laparoscopically Assisted Percutaneous Renal Biopsy

We performed laparoscopically assisted percutaneous renal biopsy on 4 patients with azotemia or renal dysfunction who were believed to be unsuitable candidates for percutaneous renal biopsy. Tissue adequate for diagnosis was obtained in all 4 cases. Complications included subcutaneous emphysema in 1 patient and a small splenic capsular tear in 1, which was managed laparoscopically and did not require transfusion. Bleeding from the renal biopsy occurred in 1 patient and was easily managed laparoscopically. We recommend laparoscopically assisted percutaneous renal biopsy as an alternative method of renal biopsy in patients who can tolerate general anesthesia and who are not candidates for percutaneous renal biopsy.

Combination Extracorporeal Shock Wave Lithotripsy and Percutaneous Extraction of Calculi in a Renal Allograft

Renal calculi are a well documented although uncommon complication of kidney transplantation and may be associated with significant morbidity in this immunosuppressed population with a single functioning kidney. We describe a patient who presented with 2 episodes of staphylococcal bacteremia associated with a ureteral structure and struvite calculi involving the calices, renal pelvis and proximal ureter of a cadaveric renal allograft. The patient was treated successfully with a combination of extracorporeal shock wave lithotripsy, percutaneous extraction and balloon dilation of the ureteral stricture. Renal transplant function was not altered postoperatively. In selected cases shock wave lithotripsy can be used as effective adjunctive therapy in a renal allograft harboring stones.

Ureteroscopic management of ureteral and ureteroenteral strictures.

The ureteroscopic approach to ureteral strictures has diminished morbidity because of smaller-caliber equipment, improved optics, Ho:YAG laser, and a better understanding of the risk factors for ureteral strictures. Direct visualization by means of retrograde ureteroscopy provides a safe and effective approach to treat ureteral strictures without the need for an open incision or percutaneous nephrostomy access. All patients with a ureteral stricture require an extensive evaluation and planning before treatment. Generally, patients with ureteral strictures and a history of carcinoma should undergo biopsy of the area of stricture. With recurrent cancer, patients may present with pain, nausea, vomiting, pyelonephritis, or loss of the ipsilateral renal unit. Malignant strictures tend to not respond well to balloon dilation alone. Open or laparoscopic resection and reconstruction may be indicated if there is a chance for cure. In patients who are not good surgical candidates or in those who have advanced disease, the urologist is left with the option of an indwelling stent or nephrostomy tube.

The Ureteral Access System: A Review of the Immediate Results in 43 Cases

The ureteral access set was used 43 times during an 18-month period between 1984 and 1985. Stones lodged throughout the ureter and in the renal pelvis were extracted with a success rate of 51 per cent. Of the upper tract strictures 92 per cent were dilated successfully. Filling defects were diagnosed in 88 per cent of the cases. Foreign bodies were retrieved, Double-J stents were placed and biopsies were successful in each case. Ureteral perforation in 28 per cent of the cases was caused by the dilator in 8 of 12 (19 per cent over-all). The technique and short-term results are discussed. Long-term followup data are not yet available.

SIMULATION OF VENTILATORY-INDUCED STONE MOVEMENT AND ITS EFFECT ON STONE FRACTURE DURING EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY

Because ventilation influences renal movement, we investigated the effect of stone motion on the efficiency of extracorporeal shock-wave lithotripsy (ESWL). Comparisons of the rates of fragmentation of an experimental model of renal calculi were made between simulated high-frequency jet ventilation at 100 breaths/min. with four-mm. stone movement as measured from the fluoroscope screen, conventional mechanical ventilation at 10 breaths/min. with 32-mm. stone movement as measured from the fluoroscope screen, and a static control. Fragmentation did not differ significantly between high-frequency jet ventilation and no ventilation (static control), but was significantly greater with high-frequency jet ventilation than with conventional ventilation.

The Role of Urate and Allopurinol in Stone Disease: A Review

In the past 20 years, many investigators have endeavored to shed light on the role of urate and allopurinol in stone disease. This discussion attempts to define what has been established.

Acute Mechanical Dilation of the Ureter: An Experimental Study

Forty-three kidney donor ureters were mechanically dilated in vitro with Van Buren sounds to an average of 21.2F. Thirty-three of these ureters, with an average pre-dilation diameter of 11.3F, could be dilated an additional average of 10.6F. The average dilated/nondilated diameter ratio in these ureters was 1.9. These experimental data suggest an undilated pelvic ureteral diameter and a manually dilated ureteral diameter of approximately the same size cited in the clinical literature.