Extraperitoneal placement of renal allografts in children weighing less than 15 kg.

PURPOSE: Extraperitoneal renal transplantation is not routine in small recipients, in whom transperitoneal engraftment is the norm. The outcome of extraperitoneal placement of renal allografts in children weighing less than 15 kg. was evaluated at 2 institutions. MATERIALS AND METHODS: We retrospectively reviewed all pediatric renal transplantations at 2 institutions from 1988 to 2000 and identified 29 children 14 to 72 months old (mean age 29.2) weighing less than 15 kg. (range 8 to 14.8, mean 11.2). All children underwent allograft placement extraperitoneally via a modified Gibson and low midline retroperitoneal incision in 27 and 2, respectively. A concurrent procedure was done via the same incision during 2 ipsilateral and 2 bilateral nephrectomies. RESULTS: Of the 29 patients 25 have a functioning renal allograft. In 2 cases the initial allograft was lost due to early postoperative thrombosis and acute rejection in 1 each. Two patients with a functioning allografts died of medical complications greater than 2 years after transplantation. One child required reexploration secondary to fascial dehiscence and an additional recipient required pyeloureterostomy due to ureteral necrosis after living related donor transplantation. CONCLUSIONS: Extraperitoneal renal transplantation is technically feasible in children who weigh less than 15 kg. This approach preserves the peritoneal cavity, limits potential gastrointestinal complications and allows the confinement of potential surgical complications, such as bleeding and urinary leakage. In addition, this approach provides complete access to the retroperitoneum to enable concurrent retroperitoneal surgery, such as nephrectomy, to be performed safely. We recommend that extraperitoneal renal engraftment should become routine in children weighing less than 15 kg. rather than using the more common transperitoneal approach for allograft placement.

10-year experience with extracorporeal shockwave lithotripsy in the state of Colorado.

PURPOSE: To evaluate trends in the utilization of extracorporeal shockwave lithotripsy (SWL) and the potential need for medical prophylaxis of urolithaisis in the state of Colorado. MATERIALS AND METHODS: We examined patient and stone characteristics of individuals undergoing SWL for renal or upper-ureteral stones over a 10-year period (1987-1996) at the Kidney Stone Center of the Rocky Mountains. There were no significant changes in the in-state physician referral patterns nor SWL treatment criteria over this time interval. All patients were treated on the Dornier HM3 lithotripter. From September 1999 to December 1999, 198 consecutive patients undergoing SWL filled out a 10-point questionnaire regarding their interest in medical prophylaxis of urolithiasis. RESULTS: The number of patients from Colorado rose 32.5%: from 15.7 per 100,000 population in 1987 to 20.8 per 100,000 in 1996. Patient demographics such as sex, race, age, and history of nephrolithiasis did not change. Furthermore, there were no significant changes in the treated stone size or stone location. The overall increase in treatment numbers was attributable equally to increases in the number of upper ureteral and renal stones. Of the 198 patients questioned, 114 (58%) were recurrent stone formers, but only 52 (45%) of these had been offered a metabolic evaluation. CONCLUSIONS: Over the 10 years since the introduction of WSL in Colorado, there has been a gradual increase in its utilization. This higher utilization is probably multifactorial. Patients undergoing SWL have a strong desire to prevent future stone episodes and are very interested in medical prophylaxis of their stone disease.

Anatomic and metabolic risk factors for nephrolithiasis in patients with autosomal dominant polycystic kidney disease.

The prevalence of nephrolithiasis is considerably greater in patients with autosomal dominant polycystic kidney disease (ADPKD) than in the general population. We evaluated anatomic and metabolic factors that may be associated with an increased prevalence of nephrolithiasis in patients with ADPKD. We compared anatomic parameters among ADPKD patients with or without nephrolithiasis as diagnosed by ultrasonography, whereas metabolic factors were determined by 24-hour urinary chemical analysis. Patients with ADPKD and nephrolithiasis had more renal cysts (P < 0.05) and a larger predominant renal cyst size (P < 0.005) than patients without nephrolithiasis. Concurrently, individual stone-forming kidneys had a greater cyst number (P < 0.05) and a significantly larger predominant cyst size (P < 0.01) compared with kidneys without stones. Patients with ADPKD and nephrolithiasis had a significantly lower creatinine clearance than those without nephrolithiasis (68.7 +/- 8.6 versus 94.8 +/- 5.4 mL/min, respectively; P < 0.05). Twenty-four-hour urinary analysis showed that patients with ADPKD and nephrolithiasis had significantly lower urinary volumes (P < 0. 05), and levels of urinary phosphate (P < 0.05), magnesium (P < 0. 005), and potassium (P < 0.05). Although not statistically significant, patients with ADPKD with stones tended to have lower levels of urinary citrate, and both groups showed a high percentage (range, 49% to 60%) of patients with hypocitraturia. Our data are consistent with the hypothesis that patients with ADPKD who develop nephrolithiasis do so because of increased intrarenal anatomic obstruction, as well as lower levels of such urinary inhibitors of stones as magnesium and citrate.

Role of sex hormones in experimental calcium oxalate nephrolithiasis.

It is unclear why men have a higher incidence of calcium oxalate nephrolithiasis than women. This study examined the role of sex hormones on urinary oxalate excretion and kidney stone formation in an experimental model of urolithiasis. Adult male and female Sprague Dawley rats with different sex hormone modulations were given 0.75% ethylene glycol for 2 wk to induce hyperoxaluria and kidney calcium oxalate crystal deposition. The study groups were: intact male and female rats; castrated male and female rats; intact male or female rats with opposite sex hormone implants; and castrated male and female rats with either testosterone or estradiol implants. Overall, a significant negative correlation between urinary oxalate and plasma estradiol/testosterone ratio was found. None of the estradiol-implanted rats, whether male or female, intact or castrated, developed kidney crystal deposits. The three groups of testosterone-implanted rats had a 43 to 88% rate of kidney calcium oxalate crystal deposition. These results indicate that androgens increase and estrogens decrease urinary oxalate excretion, plasma oxalate concentration, and kidney calcium oxalate crystal deposition. These findings may partly explain why nephrolithiasis is a predominantly male disease.

Salvage radical prostatectomy after failed transperineal cryotherapy: histologic findings from prostate whole-mount specimens correlated with intraoperative transrectal ultrasound images.

OBJECTIVES: This study evaluates the potential for salvage radical prostatectomy after failure of transrectal ultrasound (TRUS)-guided percutaneous cryosurgical ablation of the prostate. An additional purpose was to determine the accuracy of intraoperative TRUS to delineate the extent of freeze destruction that results from cryosurgery. METHODS: Six patients with biopsy-confirmed, Stage T3 prostate cancer underwent salvage radical prostatectomy 3 to 10 months after failing prostate cryosurgery. Zones of freeze destruction (resolving coagulative necrosis) and residual adenocarcinoma were mapped on the coverslips of whole-mount sections. Histologically proven zones of freeze destruction correlating to successfully treated prostatic tissue were compared to the hypoechoic ice ball treatment zones seen on intraoperative TRUS images. RESULTS: The whole mounts were found to contain necrotic areas of cryodestruction that appeared much smaller than predicted by intraoperative ultrasound. Each of the cases also contained residual viable adenocarcinoma. All patients are alive and clinically free of localized disease 0.5 to 12 months after salvage radical prostatectomy. CONCLUSIONS: Salvage radical prostatectomy offers an effective treatment option in patients who have failed transperineal cryosurgery of the prostate. Intraoperative TRUS predicted that the entire prostate would show freeze destruction. Whole-mount analysis, however, revealed areas of remaining unaffected adenocarcinoma and normal prostatic parenchyma. TRUS, therefore, overstimates the area of prostatic tissue destroyed by extreme cold. This finding challenges the assumption that the entire prostate is lethally frozen when its boundaries are included within the hypoechoic ice ball witnessed on TRUS.

Intravesical RTNF therapy of superficial bladder cancer. A phase I study of recombinant tumor necrosis factor administered intravesically to patients with superficial bladder cancer.

OBJECTIVE: A phase I/II study was initiated in patients with refractory localized superficial bladder cancer to establish the tolerance and toxicity of recombinant tumor necrosis factor (rTNF) given intravesically. A preliminary evaluation of patient responses to therapy was noted; however, the small trial size precluded extensive statistical assessment of the data. SETTING: A large teaching hospital, where patients were referred for treatment of recurrent superficial bladder cancer. PATIENTS: A referred sample consisting of 16 patients with a primary diagnosis of histologically documented superficial bladder cancer (stage Ta, T1, TIS), refractory to at least 1 previous therapy, were entered on the study. Eligibility criteria Included: 1) cystoscopy in last 42 days, 2) no contraindications to chemotherapy, 3) life expectancy of 3 months, and 4) informed consent. INTERVENTION: Patients were given rTNF intravesically twice weekly for 4 weeks at doses ranging from 10 to 500 mcg/m2. MAIN OUTCOME MEASURES: Adverse effects were recorded as minimal, moderate, severe, or intolerable. Patient responses were measured on the basis of clinical and laboratory signs, symptoms, and tumor size. RESULTS: We observed no severe or intolerable toxicities associated with the treatment. Two patients had complete responses, 9 had partial responses, 2 had minor responses, 1 was diagnosed with progressive disease, and 2 were not evaluated. No maximum tolerated dose was determined because rTNF was well tolerated at a maximum dose of 500 mcg/m2. CONCLUSIONS: The study drug rTNF was well tolerated up to a dose of 500 mcg/m2 and exhibited some antitumor effects against transitional cell carcinoma, but a biologically active dose was not determined. On the basis of this trial, further studies of intravesical treatment of superficial bladder cancer with rTNF appear warranted.