Symptomatic Hydronephrosis and Ureteral Calculi in Pregnancy: A Narrative Review with a Proposed Management Protocol.

Introduction: Approximately 3% of pregnancies are complicated by symptomatic hydronephrosis and up to 0.8% with urolithiasis. Pain, coupled with the possibility of superimposed infection, increases the risks of premature labor and delivery, fetal loss, and caesarian sections. Surgical intervention as well as standard ionizing radiation imaging modalities are typically avoided making this a difficult, high-risk patient cohort to manage. In this study we propose a standardized contemporaneous approach to investigations and management in the pregnant population with acute upper tract pathology analysis. Methods: A literature search of PubMed, Cochrane, and EMBASE databases was performed to identify original, peer-reviewed articles from 2010 onward on the management of ureteral calculi and symptomatic hydronephrosis occurring during pregnancy. Search yielded 5636 articles and after exclusions, 24 full-text articles met inclusion criteria for analysis. Evidence Synthesis: Ultrasound remains the cornerstone of initial investigation with MRI in reserve if the diagnosis remains uncertain. Low-dose CT imaging can be used in limited cases. Conservative approaches for symptomatic hydronephrosis as well ureteral calculi is the preferred initial management option in the well patient. If intervention is required, ureteral stent and nephrostomy can be used with informed consent on the risks and benefits of each. Primary ureteroscopy with definitive stone management in centers with the appropriate expertise can safely deliver excellent stone-free rates and symptomatic improvement. Conclusions: Individualized investigation and management plans following a structured approach in pregnant women with symptomatic hydronephrosis or calculi are discussed. At all stages, the patient, obstetrician, anesthetist, and surgeon should be involved in a shared decision-making approach.

Functional outcomes following percutaneous surgery in the solitary kidney.

PURPOSE: We assessed the impact of percutaneous renal surgery on renal function based on the modification of diet in renal disease estimated glomerular filtration rate in solitary renal units. We also determined the variables predictive of functional improvement or impairment following percutaneous surgery in solitary kidneys. MATERIALS AND METHODS: A prospective database was augmented by retrospective chart review. Between 1984 and 2007, 81 patients with a solitary kidney, which was anatomical in 61.7%, functional in 18.5%, a transplant allograft in 11.1% and unknown in 8.6%, underwent a total of 92 percutaneous procedures. Serum creatinine was measured preoperatively, postoperatively, at 1 month and at 1 year. The 4-variable modification of diet in renal disease equation was used to calculate estimated creatinine clearance. The study population was divided into 3 groups, including group 1-a change in the estimated glomerular filtration rate of 5% or less at 1 year, group 2-an increase of greater than 5% at 1 year and group 3-a decrease of greater than 5% at 1 year. Univariate and multivariate regression analysis was performed using the ordinal logistic fit model to assess the effects of variables on postoperative renal function at 1 year. RESULTS: Percutaneous intervention was performed for stone disease in 64 patients (69.6%), of whom 25 had staghorn calculi. Two patients required concomitant antegrade endopyelotomy for ureteropelvic junction obstruction. Percutaneous resection of transitional cell carcinoma was performed in 28 patients (30.4%). Of the patients 46% had baseline stage 3 chronic kidney disease. Complications developed in 8 patients (8.6%). In the entire cohort the modification of diet in renal disease estimated glomerular filtration rate was 44.7, 42.5, 55.4 and 49.9 ml per minute per 1.73 m(2) at baseline, immediately postoperatively, at 1 month and at 1 year, respectively. Female gender (OR 3.11, p = 0.0038) and an initial postoperative improvement in modification of diet in renal disease estimated glomerular filtration rate of greater than 5% (OR 6.84, p = 0.0026) were predictive of renal function improvement at 1 year on multivariate analysis. CONCLUSIONS: Percutaneous renal surgery in the solitary kidney is safe and it results in renal function preservation for up to 1 year of followup. Female gender and an immediate postoperative improvement in the modification of diet in renal disease estimated glomerular filtration rate are predictive of a sustained increase in that rate at 1 year.

Correlation of radiographic imaging and histopathology following cryoablation and radio frequency ablation for renal tumors.

PURPOSE: Followup after radio frequency ablation and cryotherapy for small renal lesions lacks pathological analysis. The definition of successful tumor ablation has been the absence of contrast enhancement on posttreatment magnetic resonance imaging or computerized tomography. We hypothesized that adding post-ablation kidney biopsy would help confirm treatment success. MATERIALS AND METHODS: From April 2002 to March 2006 a total of 109 renal lesions in 88 patients were ablated with percutaneous radio frequency ablation and from September 1997 to January 2006 a total of 192 lesions in 176 patients were treated with laparoscopic cryoablation. Patients were followed with radiographic imaging and post-ablation biopsy at 6 months. RESULTS: Radiographic success at 6 months was 85% (62 cases) and 90% (125) for radio frequency ablation and cryoablation, respectively. At 6 months 134 lesions (45%) were biopsied and success in the radio frequency ablation cohort decreased to 64.8% (24 cases), while cryoablation success remained high at 93.8% (91). Six of 13 patients (46.2%) with a 6-month positive biopsy after radio frequency ablation demonstrated no enhancement on posttreatment magnetic resonance imaging or computerized tomography. In patients treated with cryoablation all positive biopsies revealed posttreatment enhancement on imaging just before biopsy. CONCLUSIONS: We observed a poor correlation between radiographic imaging and pathological analysis. We recommend post-radio frequency ablation followup biopsy due to the significant risk of residual renal cell cancer without radiographic evidence, although to our knowledge the clinical significance of these viable cells remains to be determined. In contrast, radiographic images of renal lesions treated with cryotherapy appeared to correlate adequately with corresponding histopathological findings in our series.

Ureteroscopic versus percutaneous treatment for medium-size (1-2-cm) renal calculi.

PURPOSE: To compare the outcomes of percutaneous nephrolithotomy (PCNL) and ureterorenoscopy (URS) for 1- to 2-cm renal calculi with specific reference to the stone clearance rate and morbidity. PATIENTS AND METHODS: The records of 27 patients who underwent either PCNL (N = 15) or URS (N = 12) by standard techniques over an 8-month period for renal calculi between 1 and 2 cm were reviewed retrospectively. Demographic, intraoperative, and postoperative data were accrued and compared to identify any statistically significant differences. The median stone burden was slightly but not significantly higher in the PCNL group (1.8 cm v 1.25 cm; P = 0.19). Postoperative plain films were used to confirm stone clearance. RESULTS: The procedure was technically successful in all 27 patients. No patient in either group required a repeat session or ancillary procedure. All 15 PCNL procedures were completed through a single percutaneous tract. The PCNL and URS groups were equivalent with respect to operative time (79.0 minutes v 68.5 minutes) and incidence of complications (2 v 0). No patient in either group had significant hemorrhage or required blood transfusion. The overall stone-free rate was 87% for PCNL and 67% for URS (P = 0.36). CONCLUSIONS: Both PCNL and URS are effective options for renal calculi between 1 and 2 cm. The stonefree and complication rates for PCNL are higher, but the differences were not statistically significant in our series. The operative times are statistically equivalent, despite the potentially longer fragmentation times required for URS. The choice of treatment ultimately depends on the individual surgeon's preference and level of expertise.

Second prize: preliminary experience with the Niris optical coherence tomography system during laparoscopic and robotic prostatectomy.

PURPOSE: To evaluate the feasibility of high-resolution optical coherence tomography (OCT) in the identification of neurovascular bundles (NVBs) during laparoscopic and robotic radical prostatectomy (LRP). PATIENTS AND METHODS: Between November 2005 and March 2006, 24 patients undergoing transperitoneal laparoscopic or robotic radical prostatectomy were enrolled in this study. Once the bladder was taken down and the prostate mobilized, the Niris imaging system was deployed. In each patient, in-vivo images were obtained to determine the image characteristics of NVBs, adipose tissue, prostate capsule, and endopelvic fascia. The NVB was imaged again in vivo, after the prostate was excised. Ex-vivo images were obtained from the prostate surface to look for the presence or absence of the NVBs and correlated with the surgeon's assessment of the adequacy of nerve sparing. RESULTS: From 24 patients, we obtained more than 300 OCT images of tissue structures including endopelvic fascia, prostate capsule, NVBs, fat, lateral pedicles, and lymphatics. These images were found to correlate independently with the surgeon's impression of the tissue being imaged. Preliminary comparison with parallel histologic evaluation was performed in four patients that suggested OCT could help to identify the NVBs and prostate capsule during LRP. CONCLUSIONS: In our preliminary experience with the Niris system during LRP, OCT was able to image the NVB in all patients. This could enhance surgical precision during nerve sparing and positively impact potency rates after radical prostatectomy. Further research will be needed, including parallel histologic evaluation and follow-up, to validate the findings of OCT imaging.

Percutaneous radiofrequency ablation of tumor in transplanted kidney.

Treatment options for tumors in allograft kidneys include radical nephrectomy or nephron-sparing surgery. Nephron-sparing procedures relieve the patient of the necessity of immediate dialysis. Partial nephrectomy is technically challenging and potentially difficult because of existing comorbidities and adhesions from previous surgery. Probe ablation is technically simpler and is associated with lower morbidity, shorter hospitalization, and reduced convalescence compared with open partial nephrectomy of a renal allograft. We present an interesting case with a synchronous finding of a papillary renal cancer in a native and allograft kidney, in which the allograft tumor was treated with percutaneous radiofrequency ablation.

Percutaneous nephrolithotomy requiring multiple tracts: comparison of morbidity with single-tract procedures.

PURPOSE: To compare the morbidity of percutaneous nephrolithotomy (PCNL) requiring multiple percutaneous tracts with that of procedures requiring a single tract for calculus clearance. PATIENTS AND METHODS: Data from 20 patients undergoing PCNL through two or more percutaneous renal tracts over a 1-year period were compared with a contemporary cohort of 20 patients undergoing PCNL requiring a single tract. The mean stone size was 2157 mm(2) v 423 mm(2) (P < 0.0001), the baseline serum creatinine concentration was 1.67 mg/dL v 1.13 mg/dL (P < 0.05), and the baseline hemoglobin concentration was 11.8 g/dL v 13.4 g/dL (P < 0.05) in the multiple- and single-tract groups, respectively. RESULTS: All single-tract and 95% of multiple-tract patients were rendered stone free. The mean drop in hemoglobin was similar in the two groups (2.3 g/dL for single tract v 2.1 g/dL for multiple tracts; P = 0.55). Complications occurred in two patients in each group. Four multiple-tract patients required blood transfusion. The need for transfusion correlated with lower preoperative hemoglobin and higher preoperative serum creatinine. There was a significant rise in serum creatinine (1.67 mg/dL to 1.91 mg/dL; P < 0.05) and drop in creatinine clearance (76.9 mL/min to 67.2 mL/min; P < 0.05) in the multiple-tract group; this was more pronounced in patients with existing renal insufficiency. No significant change in renal function was seen in the single-tract group. CONCLUSIONS: Monotherapy with PCNL utilizing multiple percutaneous tracts is highly effective in the treatment of staghorn and other large-volume renal calculi. Blood loss and complication rates with such an aggressive approach are comparable to those of PCNL incorporating a single percutaneous tract for more straightforward calculi.

Probe-ablative nephron-sparing surgery: cryoablation versus radiofrequency ablation.

Over the past decade, a number of probe ablative therapies have emerged for the treatment of patients with localized renal tumors. Cryoablation and radiofrequency ablation (RFA) have been studied in the greatest detail. We present the results of 164 laparoscopic cryoablations and 82 percutaneous RFAs performed in our institution and compare them retrospectively in terms of complications, impact on renal function, follow-up imaging, and oncologic outcomes. Comparison of cryotherapy versus RFA revealed that mean tumor size was similar (2.56 cm vs 2.51 cm); however, the cryoablation group had a greater number of anteriorly located tumors (39% vs 10%), as well as fewer central tumors (6% vs 37%) and fewer solitary kidneys (24% vs 49%). Mean thermal treatment time was 19.3 minutes versus 32.2 minutes in the cryoablation and RFA groups, respectively. Radiologic evidence of tumor recurrence or persistence of disease was noted in 3 patients (1.8%) who underwent cryoablation and in 9 (11.1%) who were treated with RFA. All of have been successfully treated with repeat ablation/nephrectomy, or they are currently under observation. Complication rates were minimal in both groups; no significant impact on mean serum creatinine levels was noted. Cancer-specific survival following cryotherapy was 98% at a median follow-up of 3 years and 100% for RFA at 1-year median follow-up. Cryoablation and RFA are developmental nephron-sparing options. Early results are encouraging for both forms of probe ablation in terms of early oncologic control, preservation of renal function, and low complication rates. Longer-term oncologic data are necessary so that the true value of these treatment modalities can be determined.

Long-term efficacy of holmium laser endoureterotomy for benign ureteral strictures.

OBJECTIVES: To determine the long-term clinical and radiographic success of holmium laser endoureterotomy for nonobliterative benign ureteral strictures. METHODS: A total of 19 patients (12 women and 7 men, mean age 47.5 years) underwent holmium laser endoureterotomy for iatrogenic ureteral strictures (seven proximal, seven mid, and five distal) using semirigid ureteroscopy and a 360-microm fiber at 1 J and 10 Hz. RESULTS: Success was strictly defined as both relief of symptoms and radiographic resolution of obstruction by intravenous pyelography or diuretic renography, or both. With a median follow-up of 3.0 years, success was achieved in 13 (68.4%) of 19 patients. CONCLUSIONS: Our results have shown that holmium laser endoureterotomy is associated with a long-term success rate equivalent to, or better than, other currently available minimally invasive treatment options. Also, failure was uniformly evident within the first 3 months after treatment.

Radical prostatectomy: a comparison of open, laparoscopic and robot-assisted laparoscopic techniques.

INTRODUCTION: Surgical approaches to prostate cancer continue to evolve and patient demand for prostatectomy continues to increase. Technical modifications have expanded beyond open surgical approaches to include laparoscopy and more recently robotics. It is important that the enthusiasm that accompanies the introduction of new technology to surgery be accompanied by tangible benefits in terms of comparable oncological or functional outcomes and treatment morbidity. MATERIALS AND METHODS: A literature review was performed comparing individual experiences in large clinical centers and where available comparisons within the same institute between open retropubic radical prostatectomy (RRP), laparoscopic radical prostatectomy (LRP) and robot-assisted laparoscopic radical prostatectomy (RALP). RESULTS: Mortality was extremely low for each approach, with low post-operative pain-scores and analgesic requirements. Oncological outcomes as assessed by positive surgical margin rate were comparable between RRP (13%-21%), LRP (16%-26%) and RALP (6%-23%). Differences in the manner of data accrual and definition for continence and erectile dysfunction make comparison difficult between patient series, however in single institution series comparable continence rates and time to recovery of continence have been shown. CONCLUSIONS: Early data from LRP and RALP series are comparable to RRP in terms of margin-positivity and functional outcomes. Blood loss and transfusion rates appear to be lower for LRP and RALP compared to RRP, while financial costs remain higher than RRP. Long-term oncological results are keenly awaited. Ideally direct comparison between equally experienced surgeons in similar population groups will be required to demonstrate any inherent advantages or disadvantages of individual surgical approaches.

External validation of outcome prediction model for ureteral/renal calculi.

PURPOSE: We externally validated a previously designed neural network model to predict outcome and duration of passage for ureteral/renal calculi. The model was also evaluated using a 6 mm largest stone dimension cutoff in predicting stone outcome. MATERIALS AND METHODS: The model was previously designed on 301 patients at Albany Medical Center (free shareware from www.uroengineering.com). The model had a prediction accuracy of 86% for passage outcome and 87% for passage duration. In this study we tested the model on a separate 384 patients from 6 different external institutions to assess the prediction accuracy. All patients had a single renal/ureteral calculus by evaluation in an emergency room setting or by primary physicians and were then referred for further treatment. Model accuracy was also compared to using a 6 mm largest stone dimension cutoff in predicting the need for intervention. RESULTS: Testing on the 384 patients from all 6 external institutions revealed an outcome prediction accuracy of 88%. The area under the ROC curve was 0.9. Using a 6 mm stone size cutoff provided 79% (ROC 0.8) accuracy. The model duration of passage prediction accuracy was 80% (133 patients passed the stone, area under ROC of 0.8). CONCLUSIONS: The model provided high stone outcome prediction accuracy (ROC of 0.9 and 0.8) at the 6 external institutions, comparable to that of the design institution. The model provided higher accuracy than using only the largest stone dimension as a cutoff. Increasing experience will further assess the model's accuracy.

Endothelin in unilateral ureteral obstruction: vascular and cellular effects.

PURPOSE: Unilateral ureteral obstruction results in decreased blood flow and tissue loss in the obstructed kidney. This condition is compensated by increased perfusion and trophic changes in the contralateral kidney. Vascular mediators' effects are central to these changes and of these mediators endothelin is the most potent vasoconstrictor known. We explored the role of endothelin and the effects of endothelin receptor blockade in unilateral ureteral obstruction. MATERIALS AND METHODS: Rats were subjected to unilateral ureteral obstruction for 24 hours. Endothelin-1 mRNA expression was determined in kidney extracts from control, obstructed and contralateral (nonobstructed) kidneys. Cortical and medullary blood flow was determined in control and obstructed kidneys, and after endothelin receptor blockade with bosentan. Apoptotic rates were determined in control and obstructed kidneys after treatment with bosentan using the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end technique. RESULTS After 24 hours of unilateral ureteral obstruction endothelin-1 mRNA expression was increased in the obstructed kidney and decreased in the contralateral kidney. Obstruction was associated with a decrease in renal blood flow, which was reversed by endothelin receptor blockade. Unilateral ureteral obstruction also increased apoptosis, which was blocked by endothelin inhibition. CONCLUSIONS: Endothelin expression increases in the obstructed kidney. Inhibition of its action protects against vascular and cellular changes. Decreased endothelin expression in the contralateral kidney may facilitate trophic changes and compensatory increased blood flow.

Cytoprotective effects of nitrates in a cellular model of hydronephrosis.

BACKGROUND: The earliest insult to the kidney following the onset of ureteral obstruction is a marked elevation in collecting system pressure. This imparts a mechanical stress that is transmitted directly from the collecting system to the kidney substance. Renal tubular injury is the principal functional and histological change encountered, with glomerular changes being less marked and occurring later. Nitric oxide (NO) has been shown to protect against renal injury in UO, but its mode of action has not been clearly defined. METHODS: MDCK (canine) and HK-2 (human) renal tubular cells were grown under control conditions or subjected to mechanical strain for periods of 24 and 48 hours. Cells were studied treated with or without Fas-antibody, etoposide or diethyl maleate (DEM) alone or in combination with NG-monomethyl l-arginine (L-NMMA), sodium nitroprusside (SNP) or l-arginine. Cell proliferation and apoptosis was determined using propidium iodide DNA staining. NO production and inducible NO synthase (iNOS) expression were measured by the Griess reaction and Western blotting, respectively. RESULTS: Cells subjected to mechanical strain displayed a decrease in the proportion of cells undergoing cell division. They also showed an increased susceptibility to apoptosis. Associated with this was a decrease in Bcl-2 expression. An increase in iNOS expression was seen in cells subjected to mechanical strain, but no increase in NO production. The cellular effects of mechanical strain were reversed by SNP and l-arginine. CONCLUSIONS: Culture of renal tubule cells in an environment of mechanical strain results in an imbalance in homeostasis and a net cell loss. This can be reversed by the administration of an NO donor or precursor.