Histotripsy Treatment of Benign Prostatic Enlargement Using the Vortx Rx System: Initial Human Safety and Efficacy Outcomes.

OBJECTIVE: To assess clinical safety (primary) and efficacy (secondary) of histotripsy for treatment of symptomatic benign prostatic enlargement in a first-in human study. METHODS: Twenty-five male subjects with moderate to severe lower urinary tract symptoms, prostate size between 30 and 80 g, and no evidence of prostate cancer were enrolled at 2 sites in a prospective, single-arm study. Treatment consisted of acoustic energy delivery through the perineum with integrated real-time transrectal ultrasound monitoring using the Vortx Rx system. Follow-up evaluations were performed on postoperative day 1 and 1, 3, and 6 months. RESULTS: Twenty-five men underwent histotripsy treatment with no serious intraoperative adverse events. Postoperatively, 3 cases of transient urinary retention (<3 days), 1 case of urinary retention (8 days in duration, defined as serious), a minor anal abrasion, and microscopic hematuria were considered device-related adverse events. Debulking of targeted prostate tissue was not observed with transrectal ultrasound imaging or with endoscopic visualization, and clinically meaningful improvement in uroflow or postvoid residual urine (PVR) did not occur. However, International Prostate Symptom Score improvement at 1 month was 12.5 (52.4%) ± 6.6 points (n = 25), at 3 months was 11.9 (50.8%) ± 7.6 points (n = 24), and at 6 months was 10.4 (44.0%) ± 7.6 points (n = 24) (P <.001). CONCLUSION: Prostate histotripsy was safe and well tolerated in this pilot human trial with improvement in lower urinary tract symptoms.

Optimizing human semen cryopreservation by reducing test vial volume and repetitive test vial sampling.

OBJECTIVE: To investigate optimal test vial (TV) volume, utility and reliability of TVs, intermediate temperature exposure (-88°C to -93°C) before cryostorage, cryostorage in nitrogen vapor (VN2) and liquid nitrogen (LN2), and long-term stability of VN2 cryostorage of human semen. DESIGN: Prospective clinical laboratory study. SETTING: University assisted reproductive technology (ART) laboratory. PATIENT(S): A total of 594 patients undergoing semen analysis and cryopreservation. INTERVENTION(S): Semen analysis, cryopreservation with different intermediate steps and in different volumes (50-1,000 µL), and long-term storage in LN2 or VN2. MAIN OUTCOME MEASURE(S): Optimal TV volume, prediction of cryosurvival (CS) in ART procedure vials (ARTVs) with pre-freeze semen parameters and TV CS, post-thaw motility after two- or three-step semen cryopreservation and cryostorage in VN2 and LN2. RESULT(S): Test vial volume of 50 µL yielded lower CS than other volumes tested. Cryosurvival of 100 µL was similar to that of larger volumes tested. An intermediate temperature exposure (-88°C to -93°C for 20 minutes) during cryopreservation did not affect post-thaw motility. Cryosurvival of TVs and ARTVs from the same ejaculate were similar. Cryosurvival of the first TV in a series of cryopreserved ejaculates was similar to and correlated with that of TVs from different ejaculates within the same patient. Cryosurvival of the first TV was correlated with subsequent ARTVs. Long-term cryostorage in VN2 did not affect CS. CONCLUSION(S): This study provides experimental evidence for use of a single 100 µL TV per patient to predict CS when freezing multiple ejaculates over a short period of time (<10 days). Additionally, semen cryostorage in VN2 provides a stable and safe environment over time.

Practice based collaboration to improve the use of immediate intravesical therapy after resection of nonmuscle invasive bladder cancer.

PURPOSE: Perioperative instillation of intravesical chemotherapy after bladder tumor resection is supported by level I evidence showing a 30% decrease in tumor recurrence. However, studies of administrative data sets show poor use in practice. MATERIALS AND METHODS: We prospectively evaluated the use of perioperative intravesical chemotherapy in a multipractice quality improvement collaborative. Cases were categorized as ideal for intravesical chemotherapy (1 or 2 papillary tumors, cTa/cT1 and completely resected) and nonideal. The reasons for not administering intravesical chemotherapy in ideal cases were classified as appropriate or modifiable. Before and after comparative feedback and educational interventions we calculated judicious use of intravesical chemotherapy (nonuse in nonideal cases plus use in ideal cases plus appropriate nonuse in ideal cases) and quality improvement potential (use in nonideal cases plus nonuse in ideal cases attributable to modifiable factors). RESULTS: We accrued a total of 2,794 cases at the 5 sites in 22 months. The rate of use in ideal cases was 38% before and 34.8% after intervention (p=0.36), while use in nonideal cases decreased from 15% to 12% (p=0.08). Overall, intravesical chemotherapy was used judiciously in 83.0% to 85.7% of cases, while the remaining 14.3% to 17.0% represented quality improvement potential. CONCLUSIONS: Judicious use of perioperative intravesical chemotherapy is relatively high in routine practice. Most instances of nonuse represent appropriate clinical judgment. Utilization did not change after quality improvement interventions, suggesting that there may a ceiling effect that makes it difficult to improve care that is high quality at baseline. Moreover, decreasing unnecessary use of an intervention may be easier than encouraging appropriate use of potentially toxic therapy.

Understanding the use of immediate intravesical chemotherapy for patients with bladder cancer.

PURPOSE: Despite its established efficacy in reducing recurrence rates for patients with urothelial carcinoma, immediate intravesical chemotherapy is reportedly used infrequently. Accordingly, the Urological Surgery Quality Collaborative implemented a project aimed at understanding and improving the use of immediate intravesical chemotherapy. MATERIALS AND METHODS: Surgeons in 5 Urological Surgery Quality Collaborative practices prospectively collected clinical and baseline intravesical chemotherapy use data for patients undergoing bladder biopsy or transurethral bladder tumor resection from September 2010 through January 2012. In the second phase of data collection (June 2011 through January 2012) treating surgeons also documented reasons for not administering intravesical chemotherapy. We defined patients with 1 to 2 clinical stage Ta/T1, completely resected, papillary tumor(s) as ideal candidates for treatment with immediate intravesical chemotherapy. For ideal and nonideal patients we examined baseline use of intravesical chemotherapy across Urological Surgery Quality Collaborative practices as well as reasons for not administering therapy among ideal patients. RESULTS: Among 1,931 patients 37.2% met criteria as ideal cases for intravesical chemotherapy administration. We observed significant variation in the use of intravesical chemotherapy across Urological Surgery Quality Collaborative practices for ideal (range 27% to 50%) and nonideal cases (9% to 24%) (p <0.001). Reasons for not treating ideal candidates included lack of confirmation of malignancy (4, 2.8%), uncertainty regarding the benefits of intravesical chemotherapy (28, 19.6%) and logistic factors such as the unavailability of medication (34, 23.8%). CONCLUSIONS: Use of immediate intravesical chemotherapy by Urological Surgery Quality Collaborative practices is higher than reported elsewhere but still varies widely, even among ideal candidates. Efforts to optimize use will be aided by disseminating evidence supporting indications and benefits of intravesical chemotherapy, and by addressing local logistic factors that limit access to this evidence-based therapy.

Regional collaboration to improve radiographic staging practices among men with early stage prostate cancer.

PURPOSE: We describe findings from a Urological Surgery Quality Collaborative project focused on improving the use of radiographic staging in men with newly diagnosed prostate cancer. MATERIALS AND METHODS: From May 2009 through September 2010 Urological Surgery Quality Collaborative surgeons collected uniform data for men with newly diagnosed prostate cancer. During this period we implemented 3 phases of data collection. Unlike the baseline phase, the second and third rounds were preceded by collaborative quality improvement interventions, including comparative performance feedback, and review and dissemination of clinical guidelines. We evaluated the use of bone scans and computerized tomography across prostate cancer risk strata, Urological Surgery Quality Collaborative practice locations, and before and after quality improvement interventions. RESULTS: We collected data for 858 men with prostate cancer. Based on the D'Amico classification 44%, 39% and 17% of the men had low, intermediate and high risk cancer, respectively. Overall 25% and 22% of patients underwent staging with a bone scan or computerized tomography, respectively, ordered by a Urological Surgery Quality Collaborative urologist. Urological Surgery Quality Collaborative practices differed significantly in their baseline use of bone scans and computerized tomography for men with low and intermediate risk cancer (p<0.01). Compared with baseline practice patterns (31% bone scans, 28% computerized tomography), urologists in Urological Surgery Quality Collaborative practices ordered fewer bone and computerized tomography scans in post-intervention phases 2 (23%, 21%) and 3 (16%, 13%) of data collection (p<0.01), including a significant reduction in the use of these studies in patients with low and intermediate risk cancer (p<0.05). CONCLUSIONS: Following collaborative feedback on baseline use and review of clinical guidelines, urologists in Urological Surgery Quality Collaborative practices dramatically reduced variations in practice patterns and improved adherence with recommended staging practices.

Ideal culture time for improvement in sperm motility from testicular sperm aspirates of men with azoospermia.

PURPOSE: The motility of testicular derived spermatozoa reflects viability and predicts success during intracytoplasmic sperm injection. Although improvements in sperm motility are seen after incubation for extended periods, no guidelines suggest duration or media use for optimal improvement in motility. MATERIALS AND METHODS: Between July 1999 and February 2005 testicular aspirations were performed on 95 men with azoospermia, including 51 with obstructive azoospermia and 44 with nonobstructive azoospermia. Sperm motility was determined at initial collection and following incubation for 24 or 48 hours in processing media or Ham's F10 + protein. A mixed regression model controlling for testis side, media and baseline motility was created to analyze the change in motility between 24 and 48 hours. RESULTS: Mean motility improved from 3% to 20% at 24 hours and 25% at 48 hours for OA cases and from 0% to 5% at 24 hours and 11% at 48 hours for nonobstructive azoospermia cases. The improvement in motility from 24 to 48 hours was significant for obstructive azoospermia cases (p = 0.001). While media was a nonsignificant factor in regression models, when patients were grouped into categories of motility change there was a significantly better response to F10 compared to processing media (p = 0.03). CONCLUSIONS: Incubation in processing media or Ham's F10 + albumin media improves sperm motility with significant improvement noted between 24 and 48 hours for obstructive azoospermia cases. Ham's F10 + albumin media may provide extra benefit for cases of nonobstructive azoospermia or nerve injury. These results suggest the ideal timing of oocyte retrieval for intracytoplasmic sperm injection correlates with 48-hour sperm incubation for obstructive azoospermia cases, and 24 hours for nonobstructive azoospermia and nerve injury cases.

Early urinary retention after catheter removal following radical prostatectomy predicts for future symptomatic urethral stricture formation.

OBJECTIVES: Urinary retention after urethral catheter removal is a well-established complication of radical prostatectomy (RP). Its effect on subsequent urethral stricture formation has not been established. The objective of this study was to evaluate the association between post-RP early urinary retention (EUR) and subsequent symptomatic urethral stricture formation. METHODS: A total of 1289 patients who underwent RP from January 1998 to November 2004 at our tertiary medical center were included in a prospective database project. EUR was defined as that which occurred 7 days or earlier after urethral catheter removal and was identified by retrospective chart review. Multivariate logistic regression models were constructed to evaluate the association between EUR and symptomatic urethral stricture formation. RESULTS: Of the 1289 patients, 44 (3.4%) experienced EUR, and 16 of these patients (36.4%) developed symptomatic urethral strictures. The stricture rate for patients without EUR was 9.0% (112 of 1245). Compared with the patients without EUR, the patients with EUR had a greater rate of bladder neck contracture (94% versus 68%, P = 0.04) and exhibited a significantly decreased time to stricture formation (1.6 months versus 3.0 months, P = 0.002). After adjusting for patient age, clinical stage, surgeon, and Gleason score, the odds of developing a symptomatic urethral stricture were 4.7 times greater in the patients with EUR (95% confidence interval 2.3 to 9.6). CONCLUSIONS: The results of this study have shown that patients with EUR after RP are at a significantly greater risk of developing symptomatic urethral strictures, tend to form bladder neck contractures instead of more distal strictures, and to form strictures sooner after surgery. EUR might be a previously unrecognized risk factor for the development of post-RP urethral stricture.

Long-term follow-up after epididymectomy for chronic epididymal pain.

OBJECTIVES: Epididymectomy is an option for the relief of epididymal pain related to postoperative obstruction, epididymal cysts, or epididymitis. We performed 66 epididymectomies on 52 patients from 1996 to 2006 at our institution for localized epididymal pain. We evaluated the long-term symptomatic relief after epididymectomy. METHODS: All 52 epididymectomy patients were mailed questionnaires regarding their current pain level and satisfaction. Patients who did not return the questionnaires were interviewed by telephone for follow-up. RESULTS: Of the 52 patients, 34 returned 44 completed questionnaires (the patients with bilateral procedures were mailed a questionnaire for each side). The average age at epididymectomy was 44.2 years (range 25.0 to 67.9). The average follow-up was 45.8 months (range 4.2 to 119.3). Of the 34 procedures, 17 were left sided, 7 right sided, and 10 were bilateral; 25 had been performed for postvasectomy pain and 5 for obstruction related to hernia repair. Of the 44 cases, 31 (70%) reported no pain. Of the 13 still with pain, 8 (62%) reported less pain. Also, 90% were very satisfied or satisfied with their choice to undergo epididymectomy. CONCLUSIONS: We found excellent results after epididymectomy, especially for the indication of postvasectomy pain.

Fertility issues for men with newly diagnosed prostate cancer.

OBJECTIVES: With the increased use of prostate-specific antigen screening, younger men are being diagnosed with prostate cancer. A subset of these men is still interested in potentially having children after cancer treatment. To our knowledge, the topic of future fertility in patients with newly diagnosed prostate cancer has not previously been reported. METHODS: The charts of 8 patients with prostate cancer who were interested in future fertility before treatment were retrospectively reviewed. Preceding definitive treatment, the men underwent fertility counseling and were counseled to preserve semen before treatment. RESULTS: All 8 patients decided to have their semen stored using cryopreservation before their operation. After undergoing radical prostatectomy, one of the patients and his wife underwent successful intrauterine insemination and bore a child. CONCLUSIONS: A subset of men, regardless of age, diagnosed with prostate cancer will be interested in preserving their fertility for the future. Fertility options and potential counseling should be part of the routine pretreatment appointments in men undergoing treatment of prostate cancer.

Epididymal obstruction results in isolated sperm heads in post-vasectomy rats.

The aim of this study was to determine if, following vasectomy, epididymal obstruction resulted in changes in vasal stump fluid using a rat vasectomy model. One hundred and twenty-two mature male rats underwent bilateral surgical vasectomy and subsequent unilateral epididymal obstruction. Animals were randomly assigned to one of the five cohorts, which determined the time to kill and vasal fluid assessment. Numbers of whole sperm and sperm heads were compared between the obstructed and non-obstructed sides. Parametric analysis of microscopic vasal fluid findings was performed using a paired t-test. Whole sperm and sperm heads were detected bilaterally among the initial five cohorts. On the obstructed epididymis side, percentage of whole sperm dropped from 36.9% to less than 1% and sperm heads increased from 63.2 to 99.7% at 12 weeks post-obstruction (p < 0.05 at each time interval). On the unobstructed side, percentage of whole sperm rose from 66.3 to 89.5% and sperm heads dropped from 33.7 to 10.5% (p < 0.05 at each time interval). At 12 weeks, the difference between the obstructed and non-obstructed sides for both percentage and quantity of whole sperm and heads was significant with a p value of <0.001. In this rat model, following vasectomy and subsequent epididymal obstruction, testicular vasal stump fluid will contain progressively diminishing numbers of whole sperm and increases in the percentage and absolute numbers of sperm heads.

Premature ejaculation.

Premature ejaculation is a common entity that can have a significant impact on an individual's sexual satisfaction and quality of life. Both behavioral and pharmacological options are available and effective for men presenting with this condition.

Isolation of motile spermatozoa from semen samples using microfluidics.

A microfluidic device was designed with two parallel laminar flow channels where non-motile spermatozoa and debris would flow along their initial streamlines and exit one outlet, whereas motile spermatozoa had an opportunity to swim into a parallel stream and exit a separate outlet. Motile sperm samples were prepared with density gradient separation (n = 5). Sperm motility was assessed the following day after exposing aliquots to polydimethylsiloxane (PDMS) used to construct the device. There was no difference in sperm motility when compared with unexposed aliquots (P > 0.05). Unprocessed semen samples (n = 10) were placed in wider channels and sperm motility and strict morphology were assessed from sorted outlets. Sperm motility increased from 44 +/- 4.5% to 98 +/- 0.4% (P < 0.05) and morphology increased from 10 +/- 1.05% to 22 +/- 3.3% (P < 0.05) following processing. Finally, density gradient prepared samples (n = 6) containing 5 x 10(6) motile spermatozoa/ml and 50 x 10(6) round immature germ cells/ml were sorted and assessed in a similar fashion. The ratio of motile spermatozoa to round immature germ cells in the wide inlet (1:10) was significantly improved in the thin outlet (33:1) (P < 0.05). This microfluidic device provides a novel method for isolating motile, morphologically normal spermatozoa from semen samples without centrifugation. This technology may prove useful in isolating motile spermatozoa from oligozoospermic samples, even with high amounts of non-motile gamete and/or non-gamete cell contamination. A movie sequence showing streaming and sorting of spermatozoa may be purchased for viewing on the internet at www.rbmonline.com/Article/847 (free to web subscribers).

Legal considerations for cryopreservation of sperm and embryos.

OBJECTIVE: To summarize the case law for cryopreservation of sperm and embryos and make recommendations for desirable characteristics that should be included in a cryopreservation clinic's disposition agreements. DESIGN: A literature review of case law and legal review articles was performed. SETTING: Academic research center. PATIENT(S): None. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): None. RESULT(S): Two court cases involving cryopreserved semen and five cases involving cryopreserved embryos are reviewed. CONCLUSION(S): The state of the law surrounding cryopreservation is recent and unsettled. Disposition agreements can provide cryopreservation clinics some degree of certainty in this unsettled area of law. Those drafting cryopreservation disposition agreements are assisted by lessons learned from cryopreservation cases and insight gained from law review articles. It is evident that cryopreservation agreements will be most successful and most likely to be enforced if they are unambiguous, consistent with public policy, and include: a duration provision, each individual's contact information, the individual's provisions for use of their gametes in case of death, and responsibilities of cryopreservation clinic and individuals. Individuals must enter into agreements with a true understanding of the contained provisions.

Identifying patients who are suitable for stentless ureteroscopy following treatment of urolithiasis.

PURPOSE: Foregoing ureteral stents following ureteroscopy for urinary calculi is an evolving practice. Randomized trials support stent omission in select cases though generalizability is unclear and criteria for stentless ureteroscopy are unknown. Therefore, we sought to identify significant clinical characteristics affecting postoperative morbidity in unstented patients to provide a context for future randomized trials. MATERIALS AND METHODS: Of 837 ureteroscopic procedures for urolithiasis performed at our institution from January 1997 through January 2002 a ureteral stent was not placed in 226 (32%). Among these patients 47 had no stone at the time of the procedure leaving 219 (26%) who were treated for urinary calculus disease. Multivariate logistic regression was used to determine the association of 24 variables with postoperative morbidity. RESULTS: Of the 219 patients treated with ureteroscopy 39 (18%) had a postoperative complication, which was obstructive in 26 (12%), infectious in 10 (5%), and related to patient co-morbidity in 3 (1%). Factors associated with postoperative morbidity included renal pelvic location (p = 0.02), lithotripsy (p = 0.03), bilateral procedure (p = 0.07), history of urolithiasis (p <0.0001), diabetes mellitus (p = 0.06), recent/recurrent infection (p <0.0001), operative time 45 minutes or greater (p = 0.07), operative time 45 minutes or greater plus lithotripsy (p = 0.0004), operative time 45 minutes or greater plus ureteral dilation (p = 0.07) and bilateral stentless procedure (p = 0.005). CONCLUSIONS: Multiple patient and operative factors may predispose a patient to postoperative morbidity after a stentless procedure. Future trials should prospectively validate the role of these factors in either promoting (e.g., history of urolithiasis) or preventing (e.g., preoperative stent) a postoperative complication in the setting of stentless ureteroscopy.

Passively driven integrated microfluidic system for separation of motile sperm.

This paper describes a self-contained integrated microfluidic system that can separate motile sperm from small samples that are difficult to handle using conventional sperm-sorting techniques. The device isolates motile sperm from nonmotile sperm and other cellular debris, based on the ability of motile sperm to cross streamlines in a laminar fluid stream. The device is small, simple, and disposable yet is an integrated system complete with sample inlets, outlets, sorting channel, and a novel passively driven pumping system that provides a steady flow of liquid; it requires no external power source or controls. The device fulfills a need in clinical settings where small amounts of sperm need to be sorted. It also opens the way for convenient bioassays based on sperm motility including at-home motile sperm tests.

Ultra-rapid freezing of very low numbers of sperm using cryoloops.

BACKGROUND: With the availability of ICSI, men with severe oligozoospermia (<5x10(6)/ml) are able to reproduce. Current methods for cryopreservation of severe oligozoospermic samples are labour intensive and costly. The objective of this study was to evaluate whether freezing small numbers of motile sperm (approximately 100) was feasible using cryoloops. METHODS: Initial tests assessed the effect of various dilutions of cryoprotectants on pre-freezing sperm motility. Several solutions were further evaluated for their ability to cryoprotect sperm during ultra-rapid freezing. Sperm were placed on cryoloops and held in liquid nitrogen vapour for 5 min prior to freezing (ultra-rapid freezing) or directly submerged into liquid nitrogen. Using the optimal cryoprotectant and technique from these experiments, ultra-rapid and standard slow-rate freezing protocols were compared. RESULTS: Optimal sperm survival was seen when sperm in cryoloops were placed in liquid nitrogen vapour in test yolk buffer with 12% v/v glycerol versus other cryoprotectants. Using this cryoprotectant, post-thaw sperm motility is comparable between ultra-rapid and slow-rate freezing methods. CONCLUSION: Ultra-rapid freezing of very low numbers of sperm is feasible using cryoloops suspended in liquid nitrogen vapour for 5 min.

Radical cystectomy for bladder cancer after definitive prostate cancer treatment.

OBJECTIVES: To review our perioperative experience with patients presenting with high-risk bladder cancer who had undergone prior therapy for prostate cancer. With the increase in diagnosis and subsequent treatment of prostate cancer, more patients presenting with high-risk bladder cancer have undergone prior therapy for prostate cancer. Radical cystectomy in these patients can be technically challenging and may be associated with added morbidity. METHODS: A retrospective review of 458 patients treated with radical cystectomy between January 1993 and January 2002 revealed 29 patients (mean age 72 years) who had received definitive treatment for prostate cancer prior to cystectomy for bladder carcinoma. The initial treatment in this cohort was radical prostatectomy or external beam radiotherapy in 12 (41%) and 17 (59%) men, respectively. Cystectomy was performed for transitional cell carcinoma in 25 (86%), small cell carcinoma in 2 (6%), and sarcoma in 2 (6%) patients. RESULTS: At the time of cystectomy, the mean blood loss was 1175 mL (range 275 to 3500), and the median length of hospitalization was 8 days (range 4 to 23). No intraoperative or perioperative deaths occurred in this cohort. Twenty-seven early complications were identified in 16 (55%) of 29 patients; no rectal injuries occurred. Patients with prior radiotherapy had a higher rate of extravesical bladder carcinoma (60%) than those patients treated with prior prostatectomy (33%). An orthotopic neobladder diversion was created in 5 patients (17%). CONCLUSIONS: Patients with bladder cancer previously treated for prostate cancer with external beam radiotherapy or radical prostatectomy have an increased risk of perioperative complications compared with patients undergoing cystectomy without prior therapy. This risk is not prohibitive, and radical cystectomy should remain the treatment of choice for high-risk bladder cancer in this population. Furthermore, orthotopic urinary diversion may be a reasonable option and should be considered in select patients.

Safety and efficacy of same-session bilateral ureteroscopy.

PURPOSE: Same-session ureteroscopy for bilateral urinary calculi would potentially reduce costs and the need for a second anesthetic compared with staged procedures. We sought to establish the safety and efficacy of same-session bilateral ureteroscopy relative to procedures for staged bilateral and multiple unilateral calculi in the context of contemporary instrumentation. PATIENTS AND METHODS: A series of 626 consecutive patients underwent ureteroscopy for calculi between January 1997 and August 2001. Among these, 34 patients with bilateral calculi (11 staged and 23 treated in one sitting) and 54 patients with multiple unilateral calculi in distinct locations were included in this study. Multivariable regression was used to determine the association of patient-specific and technical factors with postoperative morbidity. RESULTS: Stone-free rates were similar in the two groups and ranged from 50% to 100% depending on stone location. Postoperative complications occurred in 6 (11%) and 3 (14%) of the patients treated for multiple unilateral and for bilateral calculi in a staged procedure, respectively, compared with 7 (29%) of those undergoing same-session bilateral ureteroscopy (P = 0.12). Logistic regression revealed that same-session bilateral ureteroscopy (odds ratio [OR] 4.0; P = 0.02) and absence of a postoperative stent (OR 1.7; P = 0.03) were associated with added morbidity. However, the cumulative risk of performing staged bilateral procedures (14% per procedure) approximated that of bilateral ureteroscopy in one sitting (29%). CONCLUSION: Bilateral ureteroscopy carries an increased risk of postoperative morbidity. The risk is proportional to the number of renal units treated and may be assumed at once (e.g., same-session) or over time (e.g., staged) as it applies to patients requiring bilateral ureteroscopy.