Do Urinary Cystine Parameters Predict Clinical Stone Activity?

PURPOSE: An accurate urinary predictor of stone recurrence would be clinically advantageous for patients with cystinuria. A proprietary assay (Litholink, Chicago, Illinois) measures cystine capacity as a potentially more reliable estimate of stone forming propensity. The recommended capacity level to prevent stone formation, which is greater than 150 mg/l, has not been directly correlated with clinical stone activity. We investigated the relationship between urinary cystine parameters and clinical stone activity. MATERIALS AND METHODS: We prospectively followed 48 patients with cystinuria using 24-hour urine collections and serial imaging, and recorded stone activity. We compared cystine urinary parameters at times of stone activity with those obtained during periods of stone quiescence. We then performed correlation and ROC analysis to evaluate the performance of cystine parameters to predict stone activity. RESULTS: During a median followup of 70.6 months (range 2.2 to 274.6) 85 stone events occurred which could be linked to a recent urine collection. Cystine capacity was significantly greater for quiescent urine than for stone event urine (mean ± SD 48 ± 107 vs -38 ± 163 mg/l, p <0.001). Cystine capacity significantly correlated inversely with stone activity (r = -0.29, p <0.001). Capacity also correlated highly negatively with supersaturation (r = -0.88, p <0.001) and concentration (r = -0.87, p <0.001). Using the suggested cutoff of greater than 150 mg/l had only 8.0% sensitivity to predict stone quiescence. Decreasing the cutoff to 90 mg/l or greater improved sensitivity to 25.2% while maintaining specificity at 90.9%. CONCLUSIONS: Our results suggest that the target for capacity should be lower than previously advised.

Irreversible electroporation of small renal masses: suboptimal oncologic efficacy in an early series.

PURPOSE: To report on the first short-term oncologic outcomes of percutaneous irreversible electroporation for small renal masses. METHODS: Patients with cT1a renal masses treated with irreversible electroporation from April 2013 through December 2016 were reviewed. Small, low complexity tumors were generally selected for irreversible electroporation using the NanoKnife® System (Angiodynamics, Latham, NY, USA). Surveillance imaging was performed post-operatively, and survival analysis was completed using the Kaplan-Meier method. RESULTS: A total of 42 tumors in 41 patients underwent irreversible electroporation. Mean tumor size was 2.0 cm with a median R.E.N.A.L nephrometry score of 5. Twenty-nine patients (71%) were discharged the same day of the procedure and no major (Clavien grade II or higher) intraoperative or post-operative complications occurred. Initial treatment success rate was 93%; our three failures (7%) underwent salvage radiofrequency ablation. With a mean follow-up of 22 months, 2-year local recurrence-free survival was 83% for patients with biopsy confirmed renal cell carcinoma, 87% with biopsy confirmed or a history of renal cell carcinoma, and 92% for the intent-to-treat cohort. CONCLUSIONS: Although with low morbidity, in comparison to extirpation and conventional thermal ablation technologies, irreversible electroporation has suboptimal short-term local disease control results in this series of small, low complexity tumors. Larger series and longer follow-up will determine the durability of this modality.

A Novel Device to Prevent Stone Fragment Migration During Percutaneous Lithotripsy: Results from an In Vitro Kidney Model.

PURPOSE: We developed a polyethylene sack (the PercSac) that fits over the shaft of a rigid nephroscope and is deployed into the collecting system to capture a stone and contain fragments during percutaneous nephrolithotomy (PCNL). We previously reported our results using the PercSac in a percutaneous cystolithopaxy model. In this study, we compare the efficiency of stone fragmentation with and without the PercSac in an anatomically correct in vitro PCNL model. MATERIALS AND METHODS: The PCNL model consisted of a human collecting system model created on a 3D printer. Ten BegoStones made in spherical molds of 2.0 cm diameter, matched for weight, were fragmented in the model using a 24F rigid nephroscope and an ultrasonic lithotripter, including five with and five without the PercSac. The total times for stone fragmentation and complete stone clearance, gross assessment of the stone-free status, and need for flexible nephroscopy to achieve a stone-free state were recorded. RESULTS: The median time for stone fragmentation was significantly shorter in the PercSac group compared with the control group (217 seconds [IQR = 169-255] vs 340 seconds [IQR = 310-356], [p = 0.028]). Likewise, the total time for complete stone clearance from the kidney was significantly shorter for the PercSac group (293 seconds [IQR = 244-347] vs 376 seconds [IQR = 375-480], [p = 0.047]). In one trial with the PercSac, residual dust remained in the kidney, while in all five trials without the PercSac small residual fragments remained. All trials without the PercSac required flexible nephroscopy with basket extraction to become stone free, while none of the trials with the PercSac required flexible nephroscopy for stone clearance. CONCLUSIONS: Ultrasonic lithotripsy using the novel PercSac stone entrapment device is more efficient and efficacious than traditional ultrasonic lithotripsy in an in vitro PCNL model. The advantage may be even more pronounced during clinical PCNL where residual fragments migrate into difficult-to-access calices. Further in vivo testing is underway.

Posterior Urethral Suspension During Robot-Assisted Radical Prostatectomy Improves Early Urinary Control: A Prospective Cohort Study.

PURPOSE: Early urinary control is a major goal for patients undergoing robot-assisted radical prostatectomy (RARP). We report our technique of posterior urethral suspension (PUS) performed at the time of urethrovesical anastomosis. PATIENTS AND METHODS: We prospectively followed men with localized prostate cancer undergoing RARP by a single surgeon from August 2012 to October 2015. Patients before April 2014 underwent only bladder neck preservation (controls), while patients after April 2014 also underwent PUS. Patients were given a modified Expanded Prostate Cancer Index Composite questionnaire, along with questions depicting objective measures of urinary control (type of pad, number of pads, wetness of pad). Time points queried were preoperatively and postoperatively at weeks 1, 2, 4, and 12. Our primary outcome was pad-free survival. RESULTS: Questionnaire response rate was 52% (56/107) for controls and 43% (36/83) for PUS. There were no differences in baseline demographics, preoperative urinary control, intraoperative variables, or postoperative complications between groups. There were few subjective improvements in urinary control for PUS compared with controls. More notable, PUS patients had significantly improved objective measures of urinary control, including less protective incontinence products at 1 and 2 weeks after catheter removal (p < 0.03). They also wore fewer pads and had less leakage on each pad that lasted from week 1 to week 4 after catheter removal (p < 0.01). PUS patients had pad-free rates of 37%, 47%, 54%, and 60% compared with controls 15%, 18%, 24%, and 36%, at weeks 1, 2, 4, and 12 after catheter removal (p = 0.07). CONCLUSION: PUS may improve objective measures of early urinary control compared with controls. With no increase in operative time and no change in complication rates, further work in a randomized setting would provide additional weight to our findings.

Comparative Effects of Irreversible Electroporation, Radiofrequency Ablation, and Partial Nephrectomy on Renal Function Preservation in a Porcine Solitary Kidney Model.

OBJECTIVE: To evaluate kidney function preservation or regeneration and pathological changes post-irreversible electroporation (IRE) in comparison with partial nephrectomy and radiofrequency ablation (RFA) in a solitary kidney porcine model. Tissue ablation using IRE has been reported to spare critical anatomic structures within or near the ablation zone with associated regeneration of adjacent parenchyma, possibly offering functional preservation. METHODS: Fifteen pigs initially underwent laparoscopic nephrectomy. The lower third of the remaining kidney was then ablated or removed with either IRE, RFA, or partial nephrectomy. Serum creatinine (SCr) was measured at baseline, 24 hours, 3, 7, 14, and 28 days postoperatively. The impact of the type of procedure on SCr over time was evaluated. Acute and chronic histological changes were analyzed and cellular viability was assessed using nicotinamide adenine dinucleotide staining in the IRE ablations. RESULTS: Ten ablations (5 IRE, 5 RFA) and 5 partial nephrectomies of the entire lower third of a solitary kidney were performed. The type of procedure did not affect SCr significantly at baseline (P = .14) or change in SCr over time (P = .48). Histologically, IRE and RFA lesions showed similar findings including coagulative necrosis that progressively was replaced by reparative stromal changes and fibrous tissue. Nicotinamide adenine dinucleotide staining of the IRE lesions at 14 and 28 days showed no viability in the necrotic areas with viable tissue at the margins demonstrating reparative changes. CONCLUSION: Large volume IRE ablation of normal renal parenchyma in the porcine model does not provide a functional advantage as compared with conventional renal tumor treatments.

Detecting positive surgical margins: utilisation of light-reflectance spectroscopy on ex vivo prostate specimens.

OBJECTIVE: To assess the efficacy of light-reflectance spectroscopy (LRS) to detect positive surgical margins (PSMs) on ex vivo radical prostatectomy (RP) specimens. MATERIALS AND METHODS: A prospective evaluation of ex vivo RP specimens using LRS was performed at a single institution from June 2013 to September 2014. LRS measurements were performed on selected sites on the prostate capsule, marked with ink, and correlated with pathological analysis. Significant features on LRS curves differentiating malignant tissue from benign tissue were determined using a forward sequential selection algorithm. A logistic regression model was built and randomised cross-validation was performed. The sensitivity, specificity, accuracy, negative predictive value (NPV), positive predictive value (PPV), and area under the receiver operating characteristic curve (AUC) for LRS predicting PSM were calculated. RESULTS: In all, 50 RP specimens were evaluated using LRS. The LRS sensitivity for Gleason score ≥7 PSMs was 91.3%, specificity 92.8%, accuracy 92.5%, PPV 73.2%, NPV 99.4%, and the AUC was 0.960. The LRS sensitivity for Gleason score ≥6 PSMs was 65.5%, specificity 88.1%, accuracy 83.3%, PPV 66.2%, NPV 90.7%, and the AUC was 0.858. CONCLUSIONS: LRS can reliably detect PSMs for Gleason score ≥7 prostate cancer in ex vivo RP specimens.

Medical management of renal stones.

The prevalence of kidney stones is increasing in industrialized nations, resulting in a corresponding rise in economic burden. Nephrolithiasis is now recognized as both a chronic and systemic condition, which further underscores the impact of the disease. Diet and environment play an important role in stone disease, presumably by modulating urine composition. Dietary modification as a preventive treatment to decrease lithogenic risk factors and prevent stone recurrence has gained interest because of its potential to be safer and more economical than drug treatment. However, not all abnormalities are likely to be amenable to dietary therapy, and in some cases drugs are necessary to reduce the risk of stone formation. Unfortunately, no new drugs have been developed for stone prevention since the 1980s when potassium citrate was introduced, perhaps because the long observation period needed to demonstrate efficacy discourages investigators from embarking on clinical trials. Nonetheless, effective established treatment regimens are currently available for stone prevention.

Use of an Electronic Medical Record to Assess Patient-Reported Morbidity Following Ureteroscopy.

BACKGROUND AND PURPOSE: With the extensive documentation afforded by our electronic medical record (EMR), we observed an unusually high number of patient-initiated encounters following ureteroscopy (URS). We sought to quantify and categorize patient encounters following URS to determine if we could identify avoidable common problems. MATERIALS AND METHODS: Following IRB approval, we reviewed the records of 298 consecutive patients with stones who underwent 314 URS procedures between July 2013 and November 2014. Patient demographics, stone characteristics and operative details, as well as telephone encounters, secure online patient-initiated (MyChart) messages, and emergency department (ED) visits following URS were extracted from our EMR (Epic, Verona, WI). We performed univariate (UVA) and multivariate (MVA) analysis to identify factors predictive of postoperative patient encounters and compared URS patients to a group of 56 patients undergoing transurethral resection of bladder tumor (TURBT) for number and type of encounters. RESULTS: We identified 443 encounters generated by 201 URS patients, including 334 telephone calls, 71 MyChart messages, and 38 ED visits. Among these encounters, 352 (79%) were medically related (pain comprised 45%) and the remainder involved scheduling issues. By UVA age, bilateral versus unilateral URS, stone location (both kidney and ureter), ureteral access sheath size, and total number of stones predicted a postoperative encounter. By MVA, only younger age and larger UAS size were independent predictors. When compared with TURBT patients, URS patients had a 2.5-fold higher risk of having a pain-related postoperative encounter (OR 2.54, 95% CI 1.08-7.04, P=0.03). CONCLUSIONS: Among patients undergoing URS for stones, two-thirds made unprompted contact with a healthcare provider and 80% of contacts involved postoperative pain, a finding that is distinct from another endoscopic procedure that does not involve upper tract manipulation. Patients do not perceive URS as the benign procedure doctors do.

An Assessment of Patient Comfort and Morbidity After Robot-Assisted Radical Prostatectomy with Suprapubic Tube Versus Urethral Catheter Drainage.

OBJECTIVE: Robot-assisted laparoscopic prostatectomy (RALP) with suprapubic tube (SPT), compared to urethral catheter (UC) drainage, has been proposed to improve patient comfort and recovery. We sought to compare short-term outcomes for pain and morbidity after RALP with SPT vs UC drainage. METHODS: Between August 2012 and 2014, 159 men underwent a RALP and prospectively completed a questionnaire addressing postoperative pain and satisfaction. Group 1 (n = 94) underwent a RALP by one surgeon who placed a UC and removed it between postoperative day (POD) 7 and 10. Group 2 (n = 65) underwent a RALP by a different surgeon who placed an SPT and UC. On POD 1, the UC was removed. On POD 9, the SPT was capped and removed on POD 11 if the patient was voiding adequately. Preoperative and intraoperative data, complications, questionnaires, and patient-reported morbidity, including unplanned telephone calls and emergency department (ED) visits, were compared between groups. RESULTS: Patient characteristics were similar between groups. One week after surgery, the penile pain score was statistically significantly lower in Group 2 compared to Group 1 (56.9% and 79.8%, respectively, reported minimal-to-moderate pain, p = 0.003). Bladder spasms and overall pain were not significantly higher for Group 1 compared to Group 2 (p > 0.05). When asked "How big a problem has your urine storage device been?," 20.2% of patients in Group 1 reported it as a "moderate-to-big" problem compared to 10.8% in Group 2 (p > 0.05). The number of catheter-related unplanned telephone encounters did not differ between the two groups (p = 0.7), however, although not statistically significant, 4.6% of patients in Group 2 presented to the ED with catheter-related issues (p = 0.07). CONCLUSION: SPT after RALP was associated with less penile pain compared to UC drainage, and modestly better patient satisfaction. There were no significant differences in bladder spasms, overall pain, and patient-reported morbidity between groups.

Light Reflectance Spectroscopy to Detect Positive Surgical Margins on Prostate Cancer Specimens.

PURPOSE: Intraoperative frozen section analysis is not routinely performed to determine positive surgical margins at radical prostatectomy due to time requirements and unproven clinical usefulness. Light reflectance spectroscopy, which measures light intensity reflected or backscattered from tissues, can be applied to differentiate malignant from benign tissue. We used a novel light reflectance spectroscopy probe to evaluate positive surgical margins on ex vivo radical prostatectomy specimens and correlate its findings with pathological examination. MATERIALS AND METHODS: Patients with intermediate to high risk disease undergoing radical prostatectomy were enrolled. Light reflectance spectroscopy was performed on suspected malignant and benign prostate capsule immediately following organ extraction. Each light reflectance spectroscopy at 530 to 830 nm was analyzed and correlated with pathological results. A regression model and forward sequential selection algorithm were developed for optimal feature selection. Eighty percent of light reflectance spectroscopy data were selected to train a logistic regression model, which was evaluated by the remaining 20% data. This was repeated 5 times to calculate averaged sensitivity, specificity and accuracy. RESULTS: Light reflectance spectroscopy analysis was performed on 17 ex vivo prostate specimens, on which a total of 11 histologically positive and 22 negative surgical margins were measured. Two select features from 700 to 830 nm were identified as unique to malignant tissue. Cross-validation when performing the predictive model showed that the optical probe predicted positive surgical margins with 85% sensitivity, 86% specificity, 86% accuracy and an AUC of 0.95. CONCLUSIONS: Light reflectance spectroscopy can identify positive surgical margins accurately in fresh ex vivo radical prostatectomy specimens. Further study is required to determine whether such analysis may be used in real time to improve surgical decision making and decrease positive surgical margin rates.

Equivocal ureteropelvic junction obstruction on diuretic renogram--should minimally invasive pyeloplasty be offered to symptomatic patients?

PURPOSE: Equivocal ureteropelvic junction obstruction refers to clinical symptoms and/or other radiological suggestions of possible ureteropelvic junction obstruction but with inconclusive results of obstruction on diuretic renogram. We evaluated long-term outcomes in patients with equivocal ureteropelvic junction obstruction treated with minimally invasive pyeloplasty. MATERIALS AND METHODS: We retrospectively analyzed the records of 125 consecutive patients who underwent minimally invasive pyeloplasty as performed by a single surgeon from May 2004 to July 2013. Of 98 patients with followup those with more than 6-month followup were included in analysis. Equivocal ureteropelvic junction obstruction, defined as half-life less than 20 minutes on diuretic renogram, was identified in 23 patients. All patients underwent transperitoneal minimally invasive pyeloplasty. We evaluated patient demographics, preoperative and postoperative symptoms and renal function. RESULTS: The 16 female and 7 male patients with equivocal ureteropelvic junction obstruction had flank pain and associated hydronephrosis on imaging. At a median followup of 20.2 months (range 7 to 75) 95.7% of patients with equivocal obstruction achieved complete symptom resolution. Mean ± SD preoperative and postoperative half-life was 14.1 ± 3.7 and 7.4 ± 4.2 minutes, respectively, for an improvement of 6.7 minutes (p < 0.001). In 1 patient (4.3%) with equivocal obstruction of a complicated iatrogenic etiology treatment ultimately failed postoperatively and endopyelotomy was required. There was no statistically significant difference in clinical or radiological success between the equivocal obstruction group and the 75 patients treated with minimally invasive pyeloplasty for definitive ureteropelvic junction obstruction (p = 0.44 and 0.07, respectively). CONCLUSIONS: In patients with radiographic equivocal ureteropelvic junction obstruction and flank pain minimally invasive pyeloplasty efficaciously provides symptomatic relief and functional preservation. Results are comparable to those in patients with high grade obstruction.

Single- versus dual-console robot-assisted radical prostatectomy: impact on intraoperative and postoperative outcomes in a teaching institution.

OBJECTIVE: To compare the outcomes of robotic-assisted laparoscopic prostatectomy (RALP) using a dual versus single-console system in a resident training program using intraoperative, perioperative and postoperative measures. METHODS: Patients with PCa who underwent RALP prior to and after implementing a dual-console system at an academic institution were reviewed from 2006-2012. All surgeries were performed by a single-faculty surgeon well after the learning curve was established. In all cases, chief residents participated in the surgery and performed progressively more portions. Demographic, intraoperative and pathologic parameters were obtained. Continence and erectile function were assessed at 6 and 12 months. Postoperative complications were graded using the Clavien-Dindo classification. Predictors of outcomes on univariate analysis were included in multivariate logistic or linear models. RESULTS: Of 381 patients, 185 and 196 underwent single- or dual-console RALP, respectively. There was a significant decrease in mean operative time using the dual-console system (222 vs. 171 min, p < 0.0001) as well as in the incidence of intraoperative complications (8.65 vs. 1.53%, p < 0.0001) and postoperative complications (14.1 vs. 6.63%, p = 0.03.) Complications of Clavien grade ≥3a occurred more frequently with a single-console system (7 vs. 1%, p = 0.003.) Differences persisted when controlling for potential confounders by multivariate regression. Postoperative measures of continence, erectile function and the rate of biochemical recurrence were similar between cohorts. CONCLUSIONS: When training resident surgeons to perform RALP, a dual-console system may improve intraoperative and perioperative outcomes. The dual-console may represent a safer, more efficient modality for robotic surgical education as compared to a single-console system.

A novel device to prevent stone fragment migration during percutaneous lithotripsy.

PURPOSE: We developed a novel device to capture stones in vivo in an enclosed bag (PercSac) to prevent dispersion of stone fragments during percutaneous nephrolithotomy (PCNL) or cystolitholapaxy. We report on our initial feasibility trials of the PercSac device. MATERIALS AND METHODS: PercSac consists of a specially designed polyethylene bag that is fitted over the shaft of a rigid nephroscope. The bag is used to first entrap the target stone, then tighten around it to allow fragmentation within the bag. Matched pairs of 10 canine bladder stones (2.5 cm maximum diameter) were fragmented in a human bladder model using the CyberWand (Olympus America, Inc.), and the procedure was assessed for markers of efficiency and effectiveness. RESULTS: Median time to entrap the stone within the PercSac was 67 seconds (range 51-185 sec). Median time for stone fragmentation was significantly shorter with the PercSac than without (182.0 sec [range 108-221] vs 296.5 sec [range 226-398], P=0.004). Overall, however, there was no significant difference in the total time to entrap and fragment the stones between the two groups. A stone-free state was not achieved for any trial without the PercSac, while 9 of 10 trials with the PercSac resulted in a stone-free state. CONCLUSIONS: Use of the PercSac in conjunction with stone fragmentation has the potential to reduce the occurrence of residual fragments after PCNL or cystolitholapaxy. Further in vitro testing in a kidney model is planned.

Prompt management of anastomotic leak or acute obstruction after minimally invasive pyeloplasty with percutaneous nephrostomy preserves outcomes.

PURPOSE: Urine leak or obstruction in the early postoperative period is a worrisome complication of pyeloplasty. Suboptimal management may risk long-term success. We evaluated percutaneous nephrostomy to manage complications of minimally invasive pyeloplasty. MATERIALS AND METHODS: We retrospectively analyzed the records of 125 patients who underwent minimally invasive pyeloplasty performed by a single surgeon from May 2004 to May 2013. All complications were catalogued and patients with anastomotic urine leakage or postoperative obstruction were identified. Less than 7 days postoperatively percutaneous nephrostomy was done in each case. Surgical success was defined as resolution of flank pain and/or improved half-time (less than 20 minutes) on diuretic renogram. RESULTS: Early percutaneous nephrostomy placement was required in 12 patients (9.6%) for symptomatic obstruction (6) or anastomotic urine leakage (6) a median of 4.5 days (range 2 to 7) postoperatively. Percutaneous nephrostomies remained in place a median of 9.5 days (range 5 to 42). Median followup was 15 months (range 2 to 80). Mean half-time was 36.4 minutes preoperatively and 11.1 minutes postoperatively. Continued postoperative obstruction (half-time greater than 20 minutes) was documented in 1 (8%) and 13 patients (11.5%) who did and did not require percutaneous nephrostomy placement, respectively. There was no statistical difference in radiological and clinical success rates between the percutaneous nephrostomy group and the 113 patients in whom minimally invasive pyeloplasty was uncomplicated (p = 0.74 and 0.28, respectively). CONCLUSIONS: In patients treated with minimally invasive pyeloplasty aggressive management of acute urinary complications with percutaneous nephrostomy placement preserved radiographic and symptomatic outcomes that were comparable to those in patients without complications.