Cost Analysis of Metallic Stents for Chronic Ureteral Obstruction: A Multicenter Study.

INTRODUCTION: Metallic and polymer ureteral stents are used to manage chronic ureteral obstruction. In general, metallic stents are more costly than polymer stents but they are changed less frequently. We examined the overall costs of using these stent types at 2 institutions. METHODS: We identified all patients in whom a metallic stent was placed at 2 academic institutions between July 2007 and July 2013. We calculated the average time to stent exchange or failure and the overall cost of metallic and polymer stent use. Costs included those associated with materials, operating room services, anesthesia and other expenses. RESULTS: We identified 86 patients in whom a total of 230 metallic stents were placed. Time to stent failure or exchange of a metallic stent was 7.4 months. The per unit cost of a polymer stent and a metallic stent was $121 and $887, respectively. The average annual cost of unilateral and bilateral metallic stents was $7,859.43 and $9,296.37, respectively. For a unilateral polymer stent that was changed every 3 months the yearly cost was $16,342. For bilateral polymer stents that were changed every 3 months the cost was $16,826 per year. If unilateral and bilateral polymer stents were changed every 6 months, the costs were $8,171 and $8,413, respectively. CONCLUSIONS: Our findings suggest that because metallic stents are changed less frequently than polymer stents, the annual expense associated with treating patients with chronic ureteral obstruction can be decreased by using metallic stents.

Three-Dimensional Numerical Simulations of Peristaltic Contractions in Obstructed Ureter Flows.

Ureteral peristalsis can be considered as a series of waves on the ureteral wall, which transfers the urine along the ureter toward the bladder. The stones that form in the kidney and migrate to the ureter can create a substantial health problem due to the pain caused by interaction of the ureteral walls and stones during the peristaltic motion. Three-dimensional (3D) computational fluid dynamics (CFD) simulations were carried out using the commercial code ansys fluent to solve for the peristaltic movement of the ureter, with and without stones. The effect of stone size was considered through the investigation of varying obstructions of 5%, 15%, and 35% for fixed spherical stone shape. Also, an understanding of the effect of stone shape was obtained through separate CFD calculations of the peristaltic ureter with three different types of stones, a sphere, a cube, and a star, all at a fixed obstruction percentage of 15%. Velocity vectors, mass flow rates, pressure gradients, and wall shear stresses were analyzed along one bolus of urine during peristalsis of the ureteral wall to study the various effects. It was found that the increase in obstruction increased the backflow, pressure gradients, and wall shear stresses proximal to the stone. On the other hand, with regard to the stone shape study, while the cube-shaped stones resulted in the largest backflow, the star-shaped stone showed highest pressure gradient magnitudes. Interestingly, the change in stone shape did not have a significant effect on the wall shear stress at the obstruction level studied here.

Crowd-Sourced Assessment of Technical Skills for Validation of Basic Laparoscopic Urologic Skills Tasks.

PURPOSE: The BLUS (Basic Laparoscopic Urologic Skills) consortium sought to address the construct validity of BLUS tasks and the wider problem of accurate, scalable and affordable skill evaluation by investigating the concordance of 2 novel candidate methods with faculty panel scores, those of automated motion metrics and crowdsourcing. MATERIALS AND METHODS: A faculty panel of surgeons (5) and anonymous crowdworkers blindly reviewed a randomized sequence of a representative sample of 24 videos (12 pegboard and 12 suturing) extracted from the BLUS validation study (454) using the GOALS (Global Objective Assessment of Laparoscopic Skills) survey tool with appended pass-fail anchors via the same web based user interface. Pre-recorded motion metrics (tool path length, jerk cost etc) were available for each video. Cronbach's alpha, Pearson's R and ROC with AUC statistics were used to evaluate concordance between continuous scores, and as pass-fail criteria among the 3 groups of faculty, crowds and motion metrics. RESULTS: Crowdworkers provided 1,840 ratings in approximately 48 hours, 60 times faster than the faculty panel. The inter-rater reliability of mean expert and crowd ratings was good (α=0.826). Crowd score derived pass-fail resulted in 96.9% AUC (95% CI 90.3-100; positive predictive value 100%, negative predictive value 89%). Motion metrics and crowd scores provided similar or nearly identical concordance with faculty panel ratings and pass-fail decisions. CONCLUSIONS: The concordance of crowdsourcing with faculty panels and speed of reviews is sufficiently high to merit its further investigation alongside automated motion metrics. The overall agreement among faculty, motion metrics and crowdworkers provides evidence in support of the construct validity for 2 of the 4 BLUS tasks.

Validation of the AUA BLUS Tasks.

PURPOSE: Standardized assessment of laparoscopic skill in urology is lacking. We investigated whether the AUA (American Urological Association) BLUS (Basic Laparoscopic Urologic Skills) skill tasks are valid to address this need. MATERIALS AND METHODS: This institutional review board approved study included 27 medical students, 42 urology residents, 18 fellows and 37 faculty urologists across 8 sites. Using the EDGE (Electronic Data Generation and Evaluation) device (Simulab, Seattle, Washington) 454 recordings were collected on peg transfer, pattern cutting, suturing and clip applying tasks, which together comprise the expert determined BLUS tasks. We collected synchronized video and tool motion data for each trial. For each task errors, time, path length, economy of motion, peak grasp force and EDGE score were collected. An expert panel of 5 faculty members performed GOALS (Global Objective Assessment of Laparoscopic Skills) evaluations on a representative subset of peg transfer and suturing skill tasks performed by 24 participants (IRR = 0.95). RESULTS: Demographically derived skill levels proved unsuitable to evaluate construct validity. Separation of mean scores by grouped skill levels was strongest for the suturing task. Objective motion metrics and errors supported construct validity vis-à-vis correlation with blinded expert video ratings (motion metrics R(2) = 0.95, p <0.01). Expert scores appeared to reward errors in suturing but not in block transfer. CONCLUSIONS: BLUS skill task performance scoring can discriminate among basic laparoscopic technical skill levels. Self-reported demographics are an unreliable source of determining laparoscopic technical skill.

Significance of Extraction Forces in Kidney Stone Basketing.

INTRODUCTION: Ureteroscopic stone extraction devices are effective tools in the management of urolithiasis, but on occasion, their improper use can cause injury to the ureter. Avulsion and perforation of the ureter as a result of excessive forces on the extraction device are some of the more serious complications of this treatment. MATERIALS AND METHODS: In this article, avulsion and perforation forces were measured by two different test setups. Eleven clinicians were asked to apply three ranges of forces (safe, cautious, and dangerous). RESULTS: The output force measurements were recorded and plotted for further analysis. The maximal average perforation forces were 7.13±2.36 N in the benchtop tests and 7.07±2.20 N in the ex-vivo porcine tests (P=0.54). The maximal average avulsion forces were measured to be 10.14±2.01 N in the benchtop tests. Although the average forces were similar in the proximal and distal parts of the ureter (P=0.27), higher values were recorded for the distal part. The operative time was noted to be significantly different in the safe and cautious force regions (P=0.006). The average forces were higher in the benchtop tests compared with the porcine ureter tests. The extraction forces were measured and were noted to be significantly different for attending physicians and residents. The results suggest the need for force feedback training for residents. CONCLUSION: The findings can be used to design a "smart device" that can provide visual force feedback to clinicians while they are operating, leading to improved patient outcome.

The use of internal stents in chronic ureteral obstruction.

PURPOSE: Despite the lack of a well delineated definition, chronic ureteral obstruction imposes significant quality of life loss, increased pathological morbidity and risk of mortality as well as substantial economic burden. Ureteral stenting serves as an important therapeutic option to alleviate obstruction. Thus, we assessed the recently published literature on chronic ureteral obstruction; treatment options; types, benefits and shortcomings of current ureteral stents; as well as outcomes and complications of chronic ureteral stenting, with the goal of providing concise management guidelines. MATERIALS AND METHODS: A systemic literature review was performed on Embase™, PubMed®, Cochrane Controlled Trials Register and Google Scholar™ on ureteral obstruction and internal ureteral stents. Relevant reviews, original research articles and their cited references were examined, and a synopsis of original data was generated on a clinically oriented basis. RESULTS: Chronic ureteral obstruction can be classified into compression that is either intrinsic or extrinsic to the ureteral wall, or obstruction that is of a benign or malignant origin. Patients with malignant ureteral obstruction generally have a poor prognosis and are often difficult to treat. The aim of stenting is to adequately drain the upper urinary tracts while minimizing hospitalization and the negative impact on quality of life. Facing the challenge of chronic ureteral obstruction, novel stents with new compositions, materials, coatings and designs have been developed. Metallic stents are emerging as efficacious and financially viable alternatives. Early stent related complications include iatrogenic injury, stent migration or patient discomfort, while late complications include infection, difficulties with stent exchange, hardware malfunction, infection and stent encrustation. CONCLUSIONS: Stenting in chronic ureteral obstruction is a complex and challenging problem. Much work is being done in this area and many options are being explored.

Ocular radiation exposure in modern urological practice.

PURPOSE: The human eye is a highly radiosensitive portion of the body and repeat radiation exposure can lead to cataract. The minimum fractionated long-term dose to initiate cataract formation is about 2,500 mSv. We determined whether further radiation related precautions are necessary to protect the eyes of the surgeon. MATERIALS AND METHODS: Radiation doses received near the right eye of the operating surgeon were measured with a thermoluminescent dosimeter badge worn near the eye of 6 urologists for a single endourological procedure at an academic center. Procedures included stent insertion, ureteroscopic lithotripsy and percutaneous nephrolithotomy. The mean radiation dose was calculated. Extrapolated doses required to potentiate cataract formation were also calculated. RESULTS: We assessed 28 urological procedures for radiation exposure, of which 13 were ureteroscopy done for calculus disease (range 0.05 to 0.66 mSv) and 7 were ureteral stent insertion (range 0.13 to 0.32 mSv). The mean radiation dose received during these cases was 0.208 mSv. Based on the mean dose and an average of 20 such cases per month, it would take about 50 years to reach the minimum threshold for progressive cataract formation. Eight percutaneous renal operations were performed and the mean dose received was 0.125 mSv (range 0.04 to 0.22). Based on 10 cases per month, this would require more than 160 years of exposure to reach the minimal threshold. CONCLUSIONS: Long-term radiation can lead to cataract formation. However, the accumulated lifetime exposure of the typical urologist may not necessitate further safety precautions, such as lead-lined glasses.

Cost analysis of metallic ureteral stents with 12 months of follow-up.

BACKGROUND AND PURPOSE: The metallic ureteral stent was first developed for patients with ureteral obstruction related to malignant disease, but it can be used in all patients needing chronic indwelling ureteral stents, including those with benign disease. The traditional method of polymer stent management often necessitates multiple exchanges per year depending on patient and logistical factors. This has significant direct financial cost and likely a negative effect on patients' overall health. The objective was to analyze and compare the costs associated with chronic indwelling metal and silicone-based ureteral stents. PATIENTS AND METHODS: A prospective database of patients undergoing metal stent placement from February 2008 to June 2010 was reviewed. Mean charges for a single traditional nonmetal and metal stent insertion were calculated. Charges were based on direct hospital charges related to stent cost and surgery. Cost data were based on the fiscal year 2010 cost for polymer or metal stent insertions. RESULTS: Twenty-one patients underwent metal stent placement at our institution. Of these, three traditional stent placements were omitted from analysis because of bundled charges for ureteroscopy at the same setting. Mean charges per single traditional and metal stent placement were $6072.75 and $9469.50, respectively. The estimated annual charges for traditional stents (3-6 exchanges) would be $18,218.25 to $36,436.50. Compared with metal stents, this is a potential financial savings of 48% to 74%. The mean direct cost to patients was 21.6% and 25.4% of the charges for metal and polymer stents, respectively. No patient needed early discontinuation of his or her metal stent because of lower urinary tract symptoms or gross hematuria. CONCLUSIONS: Metal stents are well tolerated by patients with ureteral obstruction of various etiologies and provide a significant financial benefit compared with polymer ureteral stents. For patients who are not fit for surgical intervention regarding their ureteral occlusive disease, the metal Resonance stent is a financially advantageous and well-tolerated option.

Metal ureteral stent for benign and malignant ureteral obstruction.

PURPOSE: Metal ureteral stents are a relatively new version of a device with a long history of relieving ureteral obstruction. Metal stents are effective for relieving ureteral obstruction but success regarding patient tolerability has been variable. We present our single institution experience with long-term metal ureteral stent placement. MATERIALS AND METHODS: The charts of patients undergoing metal ureteral stent placement for chronic ureteral obstruction were reviewed. Data collected included patient age, gender, diagnosis/cause of obstruction, laterality, duration of indwelling metal stent, number of routine metal stent changes, complications and early discontinuations or stent changes. RESULTS: A total of 23 patients underwent placement of metal ureteral stents between February 2008 and September 2010. Bilateral stents were placed in 5 patients and 9 underwent a yearly metal stent exchange for a total of 42 ureteral units treated with metal ureteral stents. All metal stents were placed to relieve ureteral obstruction due to ureteral stricture, ureteropelvic junction obstruction, retroperitoneal fibrosis or extrinsic malignant obstruction. There were 3 metal stent failures in 2 patients with malignant ureteral obstruction. There were no complications, or early discontinuations or changes due to adverse symptoms, patient dissatisfaction, worsening renal function or progressive hydronephrosis. CONCLUSIONS: Metal ureteral stents are effective for benign and malignant ureteral obstruction in the absence of urolithiasis. Good tolerability and annual stent exchange make metal stents an appealing alternative for patients with chronic ureteral obstruction treated with indwelling ureteral stents.

Robot-assisted laparoscopic sacrouteropexy for pelvic organ prolapse in classical bladder exstrophy.

Classical bladder exstrophy is a rare congenital anomaly with male predominance. When occurring in women, the accompanying anatomical and functional abnormalities, including pelvic organ prolapse (POP), may cause significant problems in both pediatric and adult patients. The robotic surgical approach to POP has not been described for bladder exstrophy as it has been in otherwise normal women. We report our technique with the first robot-assisted laparoscopic sacrouteropexy for Baden-Walker grade-four POP in an 18-year-old classical bladder exstrophy patient. At 12 months of follow-up, there were no issues or symptoms/evidence of recurrence of POP. To our knowledge, this is the first reported robot-assisted laparoscopic sacrouteropexy for POP in a previously repaired bladder exstrophy case. This procedure may be a viable option in selected patients.

Robot-assisted laparoscopic skills development: formal versus informal training.

INTRODUCTION: The learning curve for robotic surgery is not completely defined, and ideal training components have not yet been identified. We attempted to determine whether skill development would be accelerated with formal, organized instruction in robotic surgical techniques versus informal practice alone. MATERIALS AND METHODS: Forty-three medical students naive to robotic surgery were randomized into two groups and tested on three tasks using the robotic platform. Between the testing sessions, the students were given equally timed practice sessions. The formal training group participated in an organized, formal training session with instruction from an attending robotic surgeon, whereas the informal training group participated in an equally timed unstructured practice session with the robot. The results were compared based on technical score and time to completion of each task. RESULTS: There was no difference between groups in prepractice testing for any task. In postpractice testing, there was no difference between groups for the ring transfer tasks. However, for the suture placement and knot-tying task, the technical score of the formal training group was significantly better than that of the informal training group (p < 0.001), yet time to completion was not different. CONCLUSION: Although formal training may not be necessary for basic skills, formal instruction for more advanced skills, such as suture placement and knot tying, is important in developing skills needed for effective robotic surgery. These findings may be important in formulating potential skills labs or training courses for robotic surgery.

Supracervical robotic-assisted laparoscopic sacrocolpopexy for pelvic organ prolapse.

BACKGROUND: Supracervical robotic-assisted laparoscopic sacrocolpopexy (SRALS) is a new surgical treatment for pelvic organ prolapse that secures the cervical remnant to the sacral promontory. We present our initial experience with SRALS in the same setting as supracervical robotic-assisted hysterectomy (SRAH). METHODS: Women with vaginal vault prolapse and significant apical defects as defined by a Baden-Walker score of greater than or equal to 3 who had not undergone hysterectomy were offered SRALS in combination with SRAH. A chart review was performed to analyze operative and perioperative data. Outcome data also included patients who underwent robotic-assisted laparoscopic sacrocolpopexy (RALS) without any other procedure. RESULTS: Thirty-three patients underwent RALS, including 12 patients who underwent SRALS. All SRALS were performed following SRAH in the same setting. The mean follow-up for the RALS and SRALS patients was 38.4 months and 20.7 months, respectively. One patient in the RALS group had an apical recurrence. There were no recurrences in the SRALS group. CONCLUSIONS: SRALS is effective for repair of apical vaginal defects in patients with significant pelvic organ prolapse who have not undergone previous hysterectomy. Complications are few and recurrences rare in short- and medium-term follow-up. Greater follow-up and numbers are needed to further establish the role of this procedure.

Large bladder diverticulum presenting as an inguinal hernia.

We present the case of a 76-year-old man with a large bladder diverticulum presenting as an inguinal hernia with small bowel incarceration. Bladder herniation is extremely rare and when clinically suspected, computed tomography can be an important adjunct to diagnosis.

Primary Hodgkin lymphoma of the adrenal gland: a unique case presentation.

Adrenal "incidentalomas" are commonly found on body imaging, and treatment of these lesions 4 cm-6 cm in size is controversial. Most of these lesions are benign adrenal cortical adenomas. Lymphoma is a rare disease manifestation in the adrenal gland, and the overwhelming majority are metastatic lesions. Hodgkin lymphoma has never been reported as a primary adrenal lesion. We present a very unique case report of a 5 cm adrenal "incidentaloma" that represents the first reported case of primary Hodgkin lymphoma in the adrenal gland.

Renal insufficiency is not a contraindication for cryoablation of small renal masses.

OBJECTIVE: Small, incidental renal masses are increasingly discovered in elderly patients with comorbid disease, such as chronic renal insufficiency (CRI). Observation of these masses or nephron-sparing surgery is the standard of care for these patients if possible. Laparoscopic renal cryotherapy (LRC) has been shown to be equivalent to laparoscopic partial nephrectomy in short-term follow-up for management of these masses. We evaluated the effect of LRC in this subset of patients and compared it with the effect in a group of patients who were undergoing the same procedure and who had normal renal function. PATIENTS AND METHODS: Patients with CRI undergoing LRC for small enhancing renal masses were retrospectively evaluated for renal function changes after surgery. From February 2001 to July 2007, 123 patients underwent LRC; 77 of these had preoperative and postoperative creatinine levels (Cr) for evaluation, and 14 of these had renal insufficiency. Renal insufficiency was defined as a Cr level >1.3 mg/dL. Creatinine clearance (CrCl) was calculated by the Modification of Diet in Renal Disease equation. Complications were reviewed. RESULTS: In patients with renal insufficiency, the mean preoperative Cr level was 2.39 mg/dL and postoperative Cr level was 2.24 mg/dL (P = 0.0497); the mean preoperative CrCl was 32.3 mL/min/1.73 m(2) and postoperative CrCl was 35.2 mL/min/1.73 m(2) (P = 0.034). In patients with normal function, the mean preoperative Cr level was 0.95 mg/dL and the postoperative Cr level was 0.93 mg/dL (P = 0.33); mean preoperative CrCl was 78.6 mL/min/1.73 m(2) and postoperative CrCl was 81.6 mL/min/1.73 m(2) (P = 0.19). CONCLUSIONS: LRC appears to have minimal impact on renal function as measured by serum Cr levels. LRC is nephron sparing and can be performed regardless of preoperative renal function.

Robot-assisted laparoscopic sacrocolpopexy as management for pelvic organ prolapse.

BACKGROUND AND PURPOSE: Robot-assisted laparoscopic sacrocolpopexy (RALS) is a new surgical management option for pelvic organ prolapse that secures the apex of the vagina to the sacral promontory. Limited literature exists on outcomes of this procedure. We present our initial experience with RALS. PATIENTS AND METHODS: Women with vaginal vault prolapse and significant apical defects as defined by a Baden-Walker score of 3 or greater were offered RALS without any other procedure. Chart review was performed to analyze operative and perioperative data, including urodynamics (UDS) and Baden-Walker classification before and after surgery. Data were analyzed with comparison of presurgical and postsurgical data. RESULTS: From July 2005 through July 2007, 21 patients underwent RALS. Blood loss was negligible. Average operative time, including robot docking, was 3 hours, 14 minutes. Nineteen patients were discharged on postoperative day 1. UDS were not changed significantly. One patient had an apical recurrence. There were no operative complications or conversions; however, one patient had a small bowel obstruction 5 days after surgery necessitating laparotomy. Of the 21 patients, 12 have undergone anterior and posterior repair, 5 await repair, and 4 patients have opted for conservative management. CONCLUSIONS: RALS is effective to repair apical vaginal defects in patients with significant pelvic organ prolapse. Operative time is manageable and complications are few. Cystocele, rectocele, and UDS remain essentially unchanged by RALS. Most, if not all, patients with cystocele and rectocele will need further vaginal reconstruction after RALS, if desired. Greater follow-up and numbers are needed to further establish the role of this procedure.