The Impact of 68Ga-PSMA PET/CT and PET/MRI on the Management of Prostate Cancer.

Prostate-specific membrane antigen (PSMA) is a transmembrane protein with significantly increased expression in the cells and metastases of prostate carcinoma (CaP). PSMA-expression correlates with higher serum levels of prostate-specific antigen (PSA) and a higher Gleason score (GS). This finding has led to the development of novel imaging modalities such as 68Ga-/18F-labeled PSMA positron emission tomography/computed tomography (PET/CT) and positron emission tomography/magnetic resonance imaging (PET/MRI). This article reviews the literature pertaining to various new imaging technologies for the management of CaP. PSMA positron emission tomography/computed tomography appears to be an excellent diagnostic tool, that may drastically impact the management of a large number of patients with primary and recurrent CaP.

Evaluation of Novel Ball-Tip Holmium Laser Fiber: Impact on Ureteroscope Performance and Fragmentation Efficiency.

PURPOSE: A novel ball tip (BT) holmium laser fiber has recently been developed, which features a modified rounded tip. The modification is purported to aid in insertion and minimize damage to the ureteroscope working channel. We evaluated this laser fiber with regard to stone comminution, tip degradation, insertional force into the ureteroscope, and impact on ureteroscope deflection. MATERIALS AND METHODS: A 242 µm BT fiber and a standard flat tip (SF) fiber were compared. Four kilojoules was delivered to a BegoStone over a constant surface area using settings of 0.2/50, 0.6/6, 0.8/8, and 1 J/10 Hz. Fiber tip degradation was measured at 1 and 4 kJ. Ureteroscope deflection was measured with the Olympus URF-P5, URF-P6, and URF-V. Insertion force into a 270° angled ureteroscope sheath model was measured. RESULTS: A sample size of five fibers was used for each comminution energy setting. Comminution increased with pulse energy without significant difference between fibers. No significant differences in tip degradation were observed. Both fibers reduced deflection (10°-30°) in all ureteroscopes without significant differences between fibers. Four new fibers paired with new sheath models were used to test insertion force. The BT insertion forces were approximately one-third of the SF. One SF fiber caused significant damage to the sheath and could not be advanced completely. CONCLUSIONS: The BT fiber has comparable comminution, tip degradation, and ureteroscope deflection performance compared with the SF fiber while exhibiting reduced insertion force within an aggressively deflected working sheath. The new tip design is likely protective of the working channel without loss of performance.

Contemporary Management of Struvite Stones Using Combined Endourologic and Medical Treatment: Predictors of Unfavorable Clinical Outcome.

BACKGROUND AND PURPOSE: Struvite stones have been associated with significant morbidity and mortality, yet there has not been a report on the medical management of struvite stones in almost 20 years. We report on the contemporary outcomes of the surgical and medical management of struvite stones in a contemporary series. PATIENTS AND METHODS: A retrospective review of patients who were treated with percutaneous nephrolithotomy (PCNL) for struvite stones at Duke University Medical Center between January 2005 and September 2012 identified a total of 75 patients. Of these, 43 patients had adequate follow-up and were included in this analysis. Stone activity, defined as either stone recurrence or stone-related events, and predictors of activity were evaluated after combined surgical and medical treatment. RESULTS: The study included 43 patients with either pure (35%) or mixed (65%) struvite stones with a median age of 55±15 years (range 21-89 years). The stone-free rate after PCNL was 42%. Stone recurrence occurred in 23% of patients. Postoperatively, 30% of patients had a stone-related event, while 60% of residual stones remained stable with no growth after a median follow-up of 22 months (range 6-67 mos). Kidney function remained stable during follow-up. Independent predictors of stone activity included the presence of residual stones >0.4 cm(2), preoperative large stone burden (>10 cm(2)), and the presence of medical comorbidities (P<0.05). CONCLUSIONS: Struvite stones can be managed safely with PCNL followed by medical therapy. The majority of patients with residual fragments demonstrated no evidence of stone growth on medical therapy. With careful follow-up and medical management, kidney function can be maintained and stone morbidity can be minimized. Initial large stone burden, residual stones after surgery, and associated medical comorbidities may have deleterious effect on stone recurrence or residual stone-related events.

Balloon Dilation of the Ureter: A Contemporary Review of Outcomes and Complications.

PURPOSE: During ureteroscopy ureteral balloon dilation may be necessary to allow for passage of endoscopic instruments or access sheaths. We assessed the efficacy and complications associated with ureteral balloon dilation. MATERIALS AND METHODS: We retrospectively reviewed the records at 2 institutions from 2000 to 2012 to identify patients who underwent ureteral balloon dilation during ureteroscopic treatment of upper tract stones. An 18Fr balloon dilator was used in all cases. Patients with documented ureteral stricture, radiation therapy or urothelial cancer were excluded from analysis. Primary outcomes were the stone-free rate, operative complications, balloon dilation failure and the postoperative ureteral stricture rate. Complications were divided into intraoperative and postoperative groups according to the Satava and Clavien-Dindo classifications, respectively. RESULTS: A total of 151 patients fulfilled study criteria. Median followup was 12 months. The stone-free rate was 72% and median time to first postoperative imaging was 2.8 months. Balloon dilation failed in only 8 patients (5%). Eight intraoperative ureteral perforations (5%) were identified, which were managed by a ureteral stent in 7 patients and a percutaneous tube in 1. Endoscopic re-treatment was required in 4 patients with Satava 2b postoperative complications. The postoperative complication rate was 8% (11 cases). A single ureteral stricture was attributable to balloon dilation. CONCLUSIONS: In this contemporary review balloon dilation of the ureter before endoscopic treatment of stone disease was associated with a high success rate and few complications. Ureteral balloon dilation may decrease the need for a secondary procedure in patients undergoing ureteroscopy to manage proximal ureteral and intrarenal stones.

Does body mass index impact the outcomes of tubeless percutaneous nephrolithotomy?

OBJECTIVE: To evaluate whether body mass index (BMI) has an impact on the outcomes of tubeless percutaneous nephrolithotomy (PCNL). PATIENTS AND METHODS: We retrospectively reviewed patients who underwent tubeless PCNL at our institution from 2006 to 2011. Specifically, stone-free rates, complications, and hospital length of stay (LOS) were assessed. Patients were divided into four groups based on BMI: <25, 25-29.9, 30-34.9 and ≥35 kg/m(2) . Baseline characteristics and outcomes were compared between BMI groups. Multivariable logistic regressions were used to evaluate the independent contribution of BMI as a predictor of outcomes. RESULTS: We identified 268 patients who fulfilled study requirements. The overall stone-free and complication rates were 52.5% and 19.0%, respectively. Minor and severe complication comprised 10.4% and 8.6%, respectively. Univariate and multivariable analyses showed no association between BMI and stone-free or complication rates. However, patients with a normal BMI had significantly higher transfusion rates (P = 0.005), and were significantly more likely to have a prolonged LOS (≥2 days), when compared with an overweight BMI (P = 0.032) CONCLUSIONS: BMI did not impact the stone-free, or complication rates of tubeless PCNL. Normal BMI was found to be a risk factor for prolonged LOS, which may be due to an increase in clinically significant bleeding in this patient population. Tubeless PCNL appears to be a safe and effective procedure for the treatment of complex renal calculi, independent of BMI.

Improving the lens design and performance of a contemporary electromagnetic shock wave lithotripter.

The efficiency of shock wave lithotripsy (SWL), a noninvasive first-line therapy for millions of nephrolithiasis patients, has not improved substantially in the past two decades, especially in regard to stone clearance. Here, we report a new acoustic lens design for a contemporary electromagnetic (EM) shock wave lithotripter, based on recently acquired knowledge of the key lithotripter field characteristics that correlate with efficient and safe SWL. The new lens design addresses concomitantly three fundamental drawbacks in EM lithotripters, namely, narrow focal width, nonidealized pulse profile, and significant misalignment in acoustic focus and cavitation activities with the target stone at high output settings. Key design features and performance of the new lens were evaluated using model calculations and experimental measurements against the original lens under comparable acoustic pulse energy (E+) of 40 mJ. The -6-dB focal width of the new lens was enhanced from 7.4 to 11 mm at this energy level, and peak pressure (41 MPa) and maximum cavitation activity were both realigned to be within 5 mm of the lithotripter focus. Stone comminution produced by the new lens was either statistically improved or similar to that of the original lens under various in vitro test conditions and was significantly improved in vivo in a swine model (89% vs. 54%, P = 0.01), and tissue injury was minimal using a clinical treatment protocol. The general principle and associated techniques described in this work can be applied to design improvement of all EM lithotripters.

Digital tomosynthesis: a new technique for imaging nephrolithiasis. Specific organ doses and effective doses compared with renal stone protocol noncontrast computed tomography.

OBJECTIVE: To determine organ-specific doses (ODs) and effective dose (ED) for digital tomosynthesis (DT) and compare it with our institutional renal stone protocol noncontrast computed tomography (NCCT). METHODS: A validated anthropomorphic male phantom was placed supine on a digital GE Definium 8000 radiological scanner. Thermoluminescent dosimeters were placed in 256 locations and used to measure OD. A routine DT study was performed consisting of 2 scout images and 1 tomographic sweep in a 14.2-degree arc over the phantom. Software is used to recreate a series of coronal images from the sweep. ODs were determined as the sum of the doses for the study. Equivalent doses were calculated by multiplying OD with the appropriate tissue weighting factor. ED is the summation of the equivalent doses. OD and ED were determined in a similar fashion (using dosimeters) for a renal stone protocol NCCT and doses were compared. RESULTS: ODs for DT are significantly lower compared with NCCT. The ED for NCCT is 3.04 ± 0.34 mSv. The calculated ED for DT is 0.87 ± 0.15 mSv (2 scouts at 0.17 mSv and 0.14 mSv and 1 sweep at 0.56 mSv), P <.0001. CONCLUSION: DT exposes patients to substantially less radiation than NCCT. This is particularly true for radiation-sensitive organs. Further studies are needed to compare the sensitivity and specificity of DT as compared with NCCT. However, its low overall radiation dose makes it an ideal study for the follow-up of recurrent stone formers in the office setting.

Radiation exposure in urology: a genitourinary catalogue for diagnostic imaging.

PURPOSE: Computerized tomography use increased exponentially in the last 3 decades, and it is commonly used to evaluate many urological conditions. Ionizing radiation exposure from medical imaging is linked to the risk of malignancy. We measured the organ and calculated effective doses of different studies to determine whether the dose-length product method is an accurate estimation of radiation exposure. MATERIALS AND METHODS: An anthropomorphic male phantom validated for human organ dosimetry measurements was used to determine radiation doses. High sensitivity metal oxide semiconductor field effect transistor dosimeters were placed at 20 organ locations to measure specific organ doses. For each study the phantom was scanned 3 times using our institutional protocols. Organ doses were measured and effective doses were calculated on dosimetry. Effective doses measured by a metal oxide semiconductor field effect transistor dosimeter were compared to calculated effective doses derived from the dose-length product. RESULTS: The mean±SD effective dose on dosimetry for stone protocol, chest and abdominopelvic computerized tomography, computerized tomography urogram and renal cell carcinoma protocol computerized tomography was 3.04±0.34, 4.34±0.27, 5.19±0.64, 9.73±0.71 and 11.42±0.24 mSv, respectively. The calculated effective dose for these studies Was 3.33, 2.92, 5.84, 9.64 and 10.06 mSv, respectively (p=0.8478). CONCLUSIONS: The effective dose varies considerable for different urological computerized tomography studies. Renal stone protocol computerized tomography shows the lowest dose, and computerized tomography urogram and the renal cell carcinoma protocol accumulate the highest effective doses. The calculated effective dose derived from the dose-length product is a reasonable estimate of patient radiation exposure.

Report of a rare fistula between a Studer neobladder and external iliac artery.

A neobladder-arterial fistula is a very rare complication following cystectomy, with only 1 previously reported case. Delay in diagnosis can be rapidly fatal and requires prompt intervention. We report the case of a 63-year-old male who developed massive hematuria, and was found to have a fistula between the right external iliac artery and Studer neobladder during emergent exploratory laparotomy. Treatment success relies on a high index of suspicion and may include open operative intervention.