Assessing artificial intelligence responses to common patient questions regarding inflatable penile prostheses using a publicly available natural language processing tool (ChatGPT).

INTRODUCTION: The evolving landscape of healthcare information dissemination has been dramatically influenced by the rise of artificial intelligence (AI) driven chatbots, providing patients with accessible and interactive platforms to obtain knowledge about medical procedures and conditions. Among the various surgical interventions in urology, inflatable penile prosthesis (IPP) is a common treatment for men with erectile dysfunction. As patients increasingly seek comprehensive resources to understand what this procedure entails, AI-based chat technologies, such as ChatGPT, have become more prominent. This study aimed to assess the capacity of ChatGPT to provide accurate and easily understandable responses to common questions regarding the IPP procedure. MATERIALS AND METHODS: Ten frequently asked questions (FAQ) about the IPP procedure were presented to the ChatGPT chatbot in separate conversational sessions without follow up questions or repetitions. An evidence-based approach was employed to assess the accuracy of the chatbot's responses. Responses were categorized as "excellent response not requiring clarification," "satisfactory requiring minimal clarification," "satisfactory requiring moderate clarification," or "unsatisfactory requiring substantial clarification." RESULTS: Upon review, 70% of ChatGPT's answers to questions regarding the IPP procedure were rated as "excellent," not necessitating further clarification. Twenty percent were considered "satisfactory," requiring minimal clarification, notably on the omission of statistical data and the depth of discussion on certain topics. Ten percent of the responses were "unsatisfactory," requiring substantial clarification, including a failure to provide a definitive answer when necessary. CONCLUSIONS: This study reveals that ChatGPT has a substantial capability to produce evidence-based, understandable responses to a majority of common questions related to the IPP procedure. While there is room for improvement, ChatGPT can serve as an advantageous tool for patient education, enhancing preoperative understanding and contributing to informed decision-making during urological consultations for IPP.

Lowering positive margin rates at radical prostatectomy by color coding of biopsy specimens to permit individualized preservation of the neurovascular bundles: is it feasible? a pilot investigation.

OBJECTIVE: To evaluate whether color-coding of prostate core biopsy specimens aids in preservation of the neurovascular bundles from an oncological perspective. MATERIALS AND METHODS: MRI guided transrectal ultrasound and biopsy of the prostate were performed in 51 consecutive patients suspected of being at high risk for harboring prostate cancer. Core specimens were labeled with blue dye at the deep aspect and red dye at the superficial peripheral aspect of the core. The distance from the tumor to the end of the dyed specimen was measured to determine if there was an area of normal tissue between the prostate capsule and tumor. RESULTS: Of the 51 patients undergoing prostate biopsy, 30 (58.8%) were found to have cancer of the prostate: grade group 1 in 13.7%, 2 in 25.5%, 3 in 7.8%, 4 in 7.8% and 5 in 3.9% of the cohort. A total of 461 cores were analyzed in the cohort, of which 122 showed cancer. Five patients opted to undergo robotic assisted laparoscopic radical prostatectomy. No patients had a positive surgical margin (PSM) or extra prostatic extension (EPE) on radical prostatectomy if there was a margin of normal prostatic tissue seen between the dye and the tumor on prostate biopsy. CONCLUSION: Color-coding of prostate biopsy core specimens may assist in tailoring the approach for preservation of the neurovascular bundles without compromising early oncological efficacy. Further study is required to determine whether this simple modification of the prostate biopsy protocol is valuable in larger groups of patients.

Quantification of risk factors in 500 patients with postoperative urinary retention.

INTRODUCTION: An Institutional Quality and Safety Initiative to reduce postoperative urinary retention (POUR) and improve patient safety indicators (PSIs) was undertaken after a nurse driven protocol for catheter removal lead to an increase in POUR. The aim of this study was to identify the number of risk factors present in patients with POUR while examining the prevalence of those risk factors individually. MATERIALS AND METHODS: A retrospective review of our institution's surgical database was performed to identify 500 consecutive cases of POUR between July 1, 2013 and July 1, 2014. POUR was defined as the inability to void postoperatively with bladder scan volumes greater than 450 mL and subsequent need for catheterization with an output greater than 450 mL. These records were individually reviewed for 15 known independent risk factors for urinary retention. Patients with incomplete records or preoperative baseline urinary retention requiring catheterization were excluded. RESULTS: Of the 500 consecutive patients with POUR, 288 (57.6%) were male and 212 (42.4%) were female. At the time of voiding trial, all 500 patients with POUR (100%) had at least one perioperative risk factor identified and over 75% had six or more (mean 6.88, median 7, range 1-12). CONCLUSIONS: Multiple perioperative risk factors are present in the vast majority of patients with POUR. Many of the risk factors are modifiable and represent an opportunity for intervention. This could ultimately lead to a risk profile which could be used to optimize timing of postoperative voiding trials, thus improving patient care (improve PSIs and patient comfort, reduce trauma) while maintaining low rates of CAUTI.

Prostate cancer in renal transplant recipients.

As patients with end-stage renal disease are receiving renal allografts at older ages, the number of male renal transplant recipients (RTRs) being diagnosed with prostate cancer (CaP) is increasing. Historically, the literature regarding the management of CaP in RTR's is limited to case reports and small case series. To date, there are no standardized guidelines for screening or management of CaP in these complex patients. To better understand the unique characteristics of CaP in the renal transplant population, we performed a literature review of PubMed, without date limitations, using a combination of search terms including prostate cancer, end stage renal disease, renal transplantation, prostate cancer screening, prostate specific antigen kinetics, immunosuppression, prostatectomy, and radiation therapy. Of special note, teams facilitating the care of these complex patients must carefully and meticulously consider the altered anatomy for surgical and radiotherapeutic planning. Active surveillance, though gaining popularity in the general low risk prostate cancer population, needs further study in this group, as does the management of advance disease. This review provides a comprehensive and contemporary understanding of the incidence, screening measures, risk stratification, and treatment options for CaP in RTRs.

Totally intracorporeal robot-assisted laparoscopic reverse seven ileal ureteric reconstruction.

We describe the first reported case of completely intracorporeal robot-assisted laparoscopic reverse seven ileal ureteric reconstruction. The patient was a woman with bilateral, long segment ureteric strictures secondary to pelvic surgery and radiation. This report demonstrates that robotic reconstruction is a viable option even in a complex patient with a hostile abdomen.

Common vitamin D pathway gene variants reveal contrasting effects on serum vitamin D levels in African Americans and European Americans.

Vitamin D deficiency is more common among African Americans (AAs) than among European Americans (EAs), and epidemiologic evidence links vitamin D status to many health outcomes. Two genome-wide association studies (GWAS) in European populations identified vitamin D pathway gene single-nucleotide polymorphisms (SNPs) associated with serum vitamin D [25(OH)D] levels, but a few of these SNPs have been replicated in AAs. Here, we investigated the associations of 39 SNPs in vitamin D pathway genes, including 19 GWAS-identified SNPs, with serum 25(OH)D concentrations in 652 AAs and 405 EAs. Linear and logistic regression analyses were performed adjusting for relevant environmental and biological factors. The pattern of SNP associations was distinct between AAs and EAs. In AAs, six GWAS-identified SNPs in GC, CYP2R1, and DHCR7/NADSYN1 were replicated, while nine GWAS SNPs in GC and CYP2R1 were replicated in EAs. A CYP2R1 SNP, rs12794714, exhibited the strongest signal of association in AAs. In EAs, however, a different CYP2R1 SNP, rs1993116, was the most strongly associated. Our models, which take into account genetic and environmental variables, accounted for 20 and 28 % of the variance in serum vitamin D levels in AAs and EAs, respectively.

The Development of an Artificial Intelligence Model Based Solely on Computer Tomography Successfully Predicts Which Patients Will Pass Obstructing Ureteral Calculi.

OBJECTIVE: To improve upon prior attempts to predict which patients will pass their obstructing ureteral stones, we developed a machine learning algorithm to predict the passage of obstructing ureteral stones using only the CT scan at a patient's initial presentation. METHODS: We obtained Institutional Review Board approval to conduct a retrospective study by extracting data from all patients with an obstructing 3-10 mm ureteral stone. We included patients with sufficient data to be categorized as having either passed or failed to pass an obstructing ureteral stone. We developed a 3D-convolutional neural network (CNN) model using a dynamic learning rate, the Adam optimizer, and early stopping with 10-fold cross-validation. Using this model, we calculated the area under the curve (AUC) and developed a model confusion matrix, which we compared with a model based only on the largest dimension of the stone. RESULTS: A total of 138 patients met inclusion criteria and had adequate images that could be preprocessed and included in the study. Seventy patients failed to pass their ureteral stones, and 68 patients passed their stones. For the 3D-CNN model, the mean AUC was 0.95 with an overall mean sensitivity of 95% and mean specificity of 77%, which outperformed the model based on stone-size. CONCLUSION: The 3D-CNN model predicts which patients will pass their obstructing ureteral stones based on CT scan alone and does not require any further measurements. This can provide useful clinical information which may help obviate the need for a delay in care for patients who inevitably require surgical intervention.

Racial disparity in the utilization of immunotherapy for advanced prostate cancer.

PURPOSE: To identify whether there was a disparity in the utilization of immunotherapy in the treatment of black patients with metastatic castration resistant prostate cancer (mCRPC). METHODS: Using the National Cancer Database, we identified patients between 2010- 2015 with likely minimally/asymptomatic mCRPC. We analyzed annual trends for chemotherapy and immunotherapy use and compared utilization by demographic and clinical features. Multivariable analysis was performed to determine predictors of receiving immunotherapy vs chemotherapy. RESULTS: We identified 1301 patients with likely mCRPC. The majority were non Hispanic White (NHW - 63 %) and 23 % were non-Hispanic Black (NHB). Overall, there was increased utilization of immunotherapy in mCRPC from 2010 onwards, with the peak occurring in 2014 (4.6 %). Chemotherapy use increased significantly, peaking in 2014 to 26.1 %. However, the increased utilization of immunotherapy in the mCRPC was mainly seen in White patients: from 50 % to 74.2 % of the cohort. Conversely, there was a decrease in utilization of immunotherapy among Black mCPRC patients: from 50 % to 25.8 %. On multivariable analysis, there was no statistically significant difference between treatment types by race. CONCLUSION: FDA approval of Sipuleucel-T for mCRPC led to increased utilization of immunotherapy shortly thereafter, but this was mainly noted in white patients. Black patients comparatively did not exhibit increased utilization of this novel agent after 2010. Further studies are necessary to help understand barriers to access to new treatment in mCRPC and eliminate the burden of disease in minority populations."

Increase in searches for erectile dysfunction during winter: seasonal variation evidence from Google Trends in the United States.

Several diseases associated with erectile dysfunction (ED), such as type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD), are known to have seasonal variation, with increased incidence during winter months. However, no literature exists on whether this chronological-seasonal evolution is also present within ED symptomatology. We hypothesized ED would follow the seasonal pattern of its lifestyle-influenced comorbid conditions and exhibit increased incidence during winter months. In order to investigate the seasonal variation of ED in the United States between 2009 and 2019, Internet search query data were obtained using Google Trends. Normalized search volume was determined during the winter and summer seasons for ED, other diseases known to be significantly associated with ED (T2DM and CAD), kidney stones (positive control), and prostate cancer (negative control). There were significantly more internet search queries for ED during the winter than during the summer (p = 0.001). CAD and T2DM also had significantly increased search volume during winter months compared to summer months (p < 0.001 and p = 0.011, respectively). By contrast, searches for kidney stones were significantly increased in the summer than in the winter (p < 0.001). There was no significant seasonal variation in the relative search frequency for prostate cancer (p = 0.75). In conclusion, Google Trends internet search data across a ten-year period in the United States suggested a seasonal variation in ED, which implies an increase in ED during winter. This novel finding in ED epidemiology may help increase awareness of ED's associated lifestyle risk factors, which may facilitate early medical evaluation and treatment for those at risk of both ED and cardiovascular disease.

Safe transition to opioid-free pathway after robotic-assisted laparoscopic prostatectomy.

To determine whether local anesthetic infiltration and non-narcotic pain medications can safely reduce or eliminate opioid use following robotic-assisted laparoscopic prostatectomy while maintaining adequate pain control. After initiation of this quality-improvement project, patients undergoing robotic-assisted laparoscopic prostatectomy had surgeon-administered local anesthesia around all incisions into each successive layer from peritoneum to skin, with the majority infiltrated into the transversus abdominis muscle plane and posterior rectus sheath of the midline extraction incision. Post-operatively patients received scheduled acetaminophen plus ketorolac, renal function permitting. A retrospective review was performed for all cases over 19 months, spanning project implementation. 157 cases (76 in opioid-free pathway, 81 in standard pathway) were included. Five patients (6.6%) in the opioid-free pathway required post-operative opioids while inpatient, versus 61 (75.3%) in the standard pathway, p < .001. Mean patient-reported pain score on each post-operative day was lower in the opioid-free pathway compared to the standard pathway [day 0: 2.4 (SD 2.6) vs. 3.9 (SD 2.7), p < .001; day 1: 1.4 [SD 1.6] vs. 3.3 (SD 2.2), p < .001; day 2 0.9 (SD 1.5) vs. 2.6 (SD 1.9), p < .001]. Fewer post-operative complications were seen in the opioid-free pathway versus standard [0 vs. 5 (6.2%), p = 0.028], and there was no statistically significant difference in number of emergency room visits or readmissions within 3 weeks of surgery. The use of surgeon-administered local anesthetic plus scheduled non-narcotic analgesics can safely and significantly reduce opioid use after robotic-assisted laparoscopic prostatectomy while improving pain control.

Laparoscopic partial nephrectomy: six degrees of haemostasis.

OBJECTIVE: • To describe six steps for haemostasis and collecting system closure ('six degrees of haemostasis') that are reproducible and that minimize the two most concerning complications of laparoscopic partial nephrectomy: haemorrhage and urine leakage. METHODS: • A retrospective study of 23 consecutive laparoscopic partial nephrectomy cases performed by a single surgeon between 2005 and 2008 using the 'six degrees of haemostasis' was carried out. RESULTS: • There were no cases of intraoperative, postoperative or delayed bleeding. • There were no cases of urine leakage. CONCLUSION: • The 'six degrees of haemostasis' technique for laparoscopic partial nephrectomy described in the present study provides a reliable and reproducible method to reassure the surgeon of haemostasis and provide a decreased risk of urine leakage.

Durability of Digital Flexible Ureteroscope in University Hospital and Ambulatory Surgical Center: Is It Time to Rethink?

Introduction and Objectives: Published literature on damages to a digital flexible ureteroscope (DFU) examines a limited number of ureteroscopes and shows wide variation in its durability. The aim of this study was to compare the primary damage location, causes of DFU damages, and the durability of Karl Storz Flex-Xc digital ureteroscope between University Hospital (UH) and Ambulatory Care Surgery Center (ASC). We also evaluated the available literature on the durability of DFU. Methods: Each damaged DFU prospectively underwent a manufacturer's evaluation to determine the reason for return and primary site of damage. Hospital data on the number of ureteroscopic procedures and damaged DFUs over 3 years were retrospectively reviewed. The possible reason for the damage was classified as either intraoperative or between the procedures. The durability of DFUs, type, and cause of damage were compared between the UH and nonteaching ASC. A chi-square test was utilized for categorical variables. When cell frequencies were <5, Fisher's exact test was used. Results: During the study period, 1211 ureteroscopies were performed and 143 ureteroscopes were returned to the manufacturer. The mean number of uses was 7.45 at the UH and 16.5 at the ASC. The location and cause of damage were similar at both locations. The most common locations of primary damage were at the angle cover (70.6%) and instrument channel (19.2%). Most damage occurred during the handling of the ureteroscopes between surgical procedures (78%). On review of the literature, we found that DFUs were 6 times more durable in a nonteaching hospital. Conclusions: The DFU was more than two times as durable in the ASC as in the UH. Most incidents occurred during handling between surgical procedures. Future research is needed to examine the impact of training and certification of support staff on durability of DFUs.

Comparative analysis of 1152 African-American and European-American men with prostate cancer identifies distinct genomic and immunological differences.

Racial disparities in prostate cancer have not been well characterized on a genomic level. Here we show the results of a multi-institutional retrospective analysis of 1,152 patients (596 African-American men (AAM) and 556 European-American men (EAM)) who underwent radical prostatectomy. Comparative analyses between the race groups were conducted at the clinical, genomic, pathway, molecular subtype, and prognostic levels. The EAM group had increased ERG (P < 0.001) and ETS (P = 0.02) expression, decreased SPINK1 expression (P < 0.001), and basal-like (P < 0.001) molecular subtypes. After adjusting for confounders, the AAM group was associated with higher expression of CRYBB2, GSTM3, and inflammation genes (IL33, IFNG, CCL4, CD3, ICOSLG), and lower expression of mismatch repair genes (MSH2, MSH6) (p < 0.001 for all). At the pathway level, the AAM group had higher expression of genes sets related to the immune response, apoptosis, hypoxia, and reactive oxygen species. EAM group was associated with higher levels of fatty acid metabolism, DNA repair, and WNT/beta-catenin signaling. Based on cell lines data, AAM were predicted to have higher potential response to DNA damage. In conclusion, biological characteristics of prostate tumor were substantially different in AAM when compared to EAM.

Comparative study of in vivo lymphatic sealing capability of the porcine thoracic duct using laparoscopic dissection devices.

PURPOSE: Sealing the lymphatic vessels during abdominal and pelvic surgery is important to prevent the leakage of lymphatic fluid and its resultant sequelae. To our knowledge we compared for the first time the quality of lymphatic sealing by each of 4 commonly used laparoscopic dissection devices. MATERIALS AND METHODS: A total of 12 domestic pigs were used to test dissecting devices, including monopolar scissors (Ethicon Endo-Surgery, Cincinnati, Ohio), Harmonic ACE Scalpel, LigaSure V, EnSeal and Trissector. A midline incision was made from mid sternum to umbilicus, the diaphragm was divided and the porcine thoracic duct was isolated. In all animals each device was used to seal an area of the duct and each seal was placed at least 2 cm from the prior seal. In group 1 the thoracic duct of 6 pigs was cannulated with a 5Fr catheter and the seal was subjected to burst pressure testing using a burst pressure measuring device (Cole-Parmer, Vernon Hills, Illinois). In the 6 pigs in group 2 each seal was immediately sent for histopathological evaluation. Specimens were given a score for the extent of cautery damage, including 0-none, 1-minimal, 2-moderate, 3-severe and 4-extreme. RESULTS: A total of 64 seals were created, of which 35 were subjected to burst pressure testing. Mean size of the thoracic duct was 2.6 mm. No acute seal failures were observed with any bipolar device or the harmonic shears. However, 2 immediate failures (33%) were seen with monopolar scissors. Mean burst pressure for monopolar scissors, Harmonic ACE Scalpel, LigaSure V, EnSeal and Trissector was 46 (range 0 to 165), 540 (range 175 to 795), 258 (range 75 to 435), 453 (range 255 to 825) and 379 mm Hg (range 175 to 605), respectively (p <0.05). Trissector, Harmonic ACE Scalpel and EnSeal generated seals with significantly higher burst pressure than that of monopolar scissors (p <0.05). Histopathological evaluation revealed that LigaSure caused less thermal damage than Trissector and EnSeal (p <0.05). CONCLUSIONS: Each device tested except monopolar scissors consistently produced a supraphysiological seal and should be suitable for sealing lymphatic vessels during laparoscopic surgery.

The 'buoy' stent: evaluation of a prototype indwelling ureteric stent in a porcine model.

OBJECTIVE To assess a prototype ureteric 'buoy' stent with a 10 F upper body tapering to a 3F tail, developed to potentially reduce stent-related irritative symptoms while providing an adequate mould for healing after endopyelotomy. MATERIALS AND METHODS Eighteen Yucatan minipigs had the stent placed either into the intact ureter (phase I) or after Acucise proximal endoureterotomy (phase II). Buoy stents were compared to 10/7 F endopyelotomy stents and to standard 7 F stents in phases I and II, respectively. The pigs were assessed for vesico-ureteric reflux, hydronephrosis and infection, before stent insertion and at harvest. Stents were weighed before and after placement and the removal force was measured. Pressure/flow studies, antegrade nephrostograms and specimens for histopathology from the renal pelvis, ureter and vesico-ureteric junction (VUJ) were obtained at harvest. RESULTS Thirteen minipigs survived the entire study. Ureteric flow with the stents in situ was better for buoy stents than for 10/7 F stents (P < 0.005). Ureteric flow after endoureterotomy and subsequent stent removal was similar for buoy stents and standard 7 F stents. None of the stents refluxed. There was no difference between stents in removal force, weight change or incidence of hydronephrosis. At 1 and 12 weeks, buoy stents tended to produce lower histopathological alteration scores than control stents, especially at the VUJ (phase I, 2.0 vs 3.9, P = 0.092; phase II, 0.6 vs 1.7, P = 0.18). CONCLUSIONS The novel buoy stents are easily placed and removed via the urethra. They can cause less VUJ inflammation than standard stents while allowing for adequate ureteric flow and healing after proximal endoureterotomy.

Robotic Pyelolithotomy for the Intact Removal of a Complete Staghorn Calculus: A Feasible Approach Even After a Previous Open Pyelolithotomy.

OBJECTIVE: To describe the steps and technique of a robotic pyelolithotomy for complete removal of a left staghorn stone after a previous open pyelolithotomy. METHODS: The patient is placed in a left modified flank position with 4 laparoscopic ports placed: 12mm port for camera paramedian to the left of the midline, 8mm robotic port left lower quadrant at the level of the umbilicus, 8mm robotic port midclavicular line 2 finger breaths below the costal margin, 12mm Airseal assistant port paramedian infraumbilical. The white line of Toldt was incised and the colon was mobilized medially. Anterior Gerota's fascia was opened and tacked to the lateral abdominal wall exposing renal pelvis and parenchyma. An intraoperative ultrasound confirmed the underlying stone. A V-shaped Gil-Vernet pyelolithotomy incision was made and Prograsp forceps were used to manipulate the stone out of the renal pelvis. The collecting system was inspected and irrigated using the robotic lens. The pyelotomy was closed with 4-0 Monocryl suture on a TF needle in 2 lengths of suture, superiorly and inferiorly. Gerota's fascia was closed over the renal pelvis and the kidney was re-retroperitonealized by tacking the colon to the white line of Toldt. The specimen was retrieved through a mini-Pfannenstiel incision via a specimen bag. The patient was discharged on postoperative day 1 and seen in clinic 5 weeks later for stent removal. CONCLUSIONS: Robotic pyelolithotomy is a minimally invasive alternative that can be offered to patients with complete staghorn stones even after major open stone surgery. However case selection for this approach relies on the stone burden primarily in a dilated renal pelvis with limited calyceal projections. It is imperative to review preoperative imaging to understand the calyceal anatomy and the rotation required to free the stone from the collecting system.

Laboratory evaluation of laparoscopic vascular clamps using a load-cell device--are all clamps the same?

PURPOSE: The use of effective vascular clamps is key to successful laparoscopic partial nephrectomy. Based on our clinical experience the occlusive capabilities of vascular clamps appeared to be quite variable. We compared the occlusive force of currently available laparoscopic vascular clamps. MATERIALS AND METHODS: The jaw force of 3 laparoscopic vascular clamps (Aesculap(R), Klein Surgical Systems, San Antonio, Texas and Karl Storztrade mark) were measured by clamping a 2.2 mm compression load cell (Interface Advanced Force Measurement, Scottsdale, Arizona) in pound-force. The variables tested were handheld Satinsky, DeBakey and Storz clamps vs bulldog clamps, proximal, middle and distal application position, new vs used bulldog clamps and new vs used Satinsky handheld clamps. In addition, handheld clamps were tested according to the force generated by the notches in the locking mechanism. Force retention was also determined for all instruments after clamping a 20Fr latex rubber catheter for an hour. Finally, leak pressure studies were performed using a harvested porcine artery to determine the relationship between jaw force and leak pressure in mm Hg of bulldog and Satinsky handheld clamps using a pressure gauge (Cole-Parmer(R)). RESULTS: Handheld vascular clamps provided greater force than bulldog clamps. The proximal position closest to the hinge provided the greatest force across all instruments. Compared to new clamps the 2-year-old Klein Surgical Systems bulldog clamps showed a greater than 40% decrease in jaw force at all positions, whereas the 3-year-old Aesculap bulldog clamps decreased in jaw force by less than 9% at all positions. The 2-year-old Satinsky handheld clamps showed a decrease of 20%, 9% and 0% at the distal, middle and proximal jaw positions, respectively. Also, there was a positive correlation between force and the number of notches applied in handheld clamps. In addition, all instruments maintained jaw force after 1 hour of continuous clamping. Finally, leak pressure studies performed with used clamps showed that Klein Surgical Systems bulldog, Aesculap bulldog and Satinsky handheld clamps leaked at a pressure of 153 to 223, 465 to 795 and 1,500 to 2,600 mm Hg, respectively. CONCLUSIONS: Vascular clamps have varying occlusive forces according to clamp type, manufacturer, jaw and teeth characteristics, jaw clamping position and duration of use. However, across all clamps the jaw force was greatest at the proximal position. This is most important when applying laparoscopic bulldog clamps. In contrast, all handheld vascular clamps generated higher force than intracorporeal bulldog clamps. At 1 notch the handheld vascular clamps provided supraphysiological occlusion force regardless of position or manufacturer.

In vitro evaluation of nitinol urological retrieval coil and ureteral occlusion device: retropulsion and holmium laser fragmentation efficiency.

PURPOSE: Retropulsion of ureteral stones during laser lithotripsy may result in difficult and incomplete stone fragmentation. The Stone Cone nitinol urological retrieval coil and the NTrap nitinol ureteral occlusion device have been introduced into clinical practice to possibly limit stone retropulsion and enhance the efficiency of holmium laser (Convergent Laser Technologies, Alameda, California) stone fragmentation. MATERIALS AND METHODS: A total of 360 BegoStone Plus phantom stones (Bego USA, Smithfield, Rhode Island) of similar mass and weight were divided into 3 groups, including control, Stone Cone and NTrap. The groups were further subdivided according to fiber size (200 or 400 microm) and pulse width (350 or 700 microsec). These stones were placed in a horizontal pipette 12 mm in diameter, submerged in normal saline and disintegrated at laser settings of 1 J and 10 Hz continuously applied for 300 seconds. Retropulsion in cm and fragmentation efficiency with mass loss in mg were measured after treatment. RESULTS: The 2 devices were effective for preventing retropulsion. In the control group the mean +/- SD retropulsion distance using a 350-microsec pulse width with the 200 and 400 microm fibers was 18.4 +/- 5.9 and 14.1 +/- 4.6 cm, while it was 6.2 +/- 2.6 and 5.6 +/- 2.4, respectively, using the 700-microsec pulse width. There was a statistically significant higher loss of stone weight in the Stone Cone and NTrap experimental groups than in the control group (p <0.0001). However, there was no difference between the 2 experimental groups across all groups (p = 0.32). CONCLUSIONS: The Stone Cone and NTrap eliminated retropulsion and equally improved fragmentation efficiency. The maximum efficiency of fragmentation was seen using the 200 microm fiber at a 700-microsec pulse width.

Percutaneous and laparoscopic cryoablation of small renal masses.

PURPOSE: We reviewed our 4-year experience with percutaneous cryoablation and laparoscopy for treating small renal masses. MATERIALS AND METHODS: After institutional review board approval we retrospectively analyzed renal cryoablation procedures performed between March 2003 and October 2007. An in-depth analysis was performed concerning demographics, hospital course and short-term outcome with respect to percutaneous vs laparoscopic cryoablation. RESULTS: A total of 37 patients underwent treatment for 43 renal masses. Of the 37 patients 19 underwent laparoscopic cryoablation (24 tumors) and 18 underwent percutaneous cryoablation (19 tumors) using computerized tomography fluoroscopy. For percutaneous cryoablation a saline instillation was used in 58% of cases to move nonrenal vital structures away from the targeted renal mass. There were 5 cases of hemorrhage requiring transfusion, all of which were associated with the use of multiple cryoprobes. The transfusion rate in the percutaneous and laparoscopic cryoablation groups was 11.1% and 27.8%, respectively. Operative time was significantly longer in the laparoscopic cryoablation group compared to the percutaneous cryoablation group at 147 (range 89 to 209) vs 250.2 (range 151 to 360) minutes, respectively. The overall complication rate (including transfusion) was lower in the percutaneous cryoablation group compared to the laparoscopic cryoablation group (4 of 18 [22.2%] vs 8 of 20 [40%], respectively). Hospital stay was significantly shorter in the percutaneous vs laparoscopic cryoablation group at 1.3 vs 3.1 days, p <0.0001, respectively. Narcotic use in the percutaneous cryoablation group was more than half that used by the laparoscopic cryoablation group (5.1 vs 17.8 mg, p = 0.03, respectively). Among patients with biopsy proven renal cell carcinoma during a median followup of 11.4 and 13.4 months in the percutaneous and laparoscopic cryoablation groups, cancer specific survival was 100% and 100%, respectively, and the treatment failure rate was 5.3% and 4.2%, respectively. CONCLUSIONS: Percutaneous cryoablation is an efficient, minimally morbid method for the treatment of small renal masses and it appears to be superior to the laparoscopic approach. Short-term followup has shown no difference in tumor recurrence or need for re-treatment. Of note, hemorrhage was solely associated with the use of multiple probes.