Fully Automated Deep Learning Model to Detect Clinically Significant Prostate Cancer at MRI.

Background Multiparametric MRI can help identify clinically significant prostate cancer (csPCa) (Gleason score ≥7) but is limited by reader experience and interobserver variability. In contrast, deep learning (DL) produces deterministic outputs. Purpose To develop a DL model to predict the presence of csPCa by using patient-level labels without information about tumor location and to compare its performance with that of radiologists. Materials and Methods Data from patients without known csPCa who underwent MRI from January 2017 to December 2019 at one of multiple sites of a single academic institution were retrospectively reviewed. A convolutional neural network was trained to predict csPCa from T2-weighted images, diffusion-weighted images, apparent diffusion coefficient maps, and T1-weighted contrast-enhanced images. The reference standard was pathologic diagnosis. Radiologist performance was evaluated as follows: Radiology reports were used for the internal test set, and four radiologists' PI-RADS ratings were used for the external (ProstateX) test set. The performance was compared using areas under the receiver operating characteristic curves (AUCs) and the DeLong test. Gradient-weighted class activation maps (Grad-CAMs) were used to show tumor localization. Results Among 5735 examinations in 5215 patients (mean age, 66 years ± 8 [SD]; all male), 1514 examinations (1454 patients) showed csPCa. In the internal test set (400 examinations), the AUC was 0.89 and 0.89 for the DL classifier and radiologists, respectively (P = .88). In the external test set (204 examinations), the AUC was 0.86 and 0.84 for the DL classifier and radiologists, respectively (P = .68). DL classifier plus radiologists had an AUC of 0.89 (P < .001). Grad-CAMs demonstrated activation over the csPCa lesion in 35 of 38 and 56 of 58 true-positive examinations in internal and external test sets, respectively. Conclusion The performance of a DL model was not different from that of radiologists in the detection of csPCa at MRI, and Grad-CAMs localized the tumor. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Johnson and Chandarana in this issue.

Early apical release versus En-bloc no touch technique for holmium laser enucleation of the prostate: a high-volume single-surgeon cohort study.

PURPOSE: To determine whether the early apical release (EAR) technique for holmium laser enucleation of the prostate (HOLEP) is associated with improved perioperative outcomes compared to the En-bloc no touch (EBNT) technique. METHODS: Consecutive men treated with HOLEP by a single surgeon from August 2018 to March 2021 were identified. Beginning in June 2021 all procedures were performed using the EAR technique, and these were compared to the preceding cases done with the EBNT technique. Intraoperative outcomes included operative time, need for open conversion, enucleation efficiency (tissue removed per minute of OR time), and enucleation ratio (tissue removed relative to preoperative gland size on imaging). Postoperative outcomes included catheter reinsertion, blood transfusion, and complications classified by the Clavien-Dindo scale. RESULTS: We identified 801 men, including 571 (71%) treated with EBNT and 230 (29%) with EAR. Median preoperative characteristics were similar between groups. The EAR approach was associated with significantly longer mean operating room time, 100.5 min versus 91.9 min, p = 0.003. However, EAR patients had a much lower rate of conversion to open cystotomy (0.43% versus 3.0%). There were no significant differences in rate of catheter reinsertion or perioperative complications between groups (p > 0.05). CONCLUSION: EAR technique by an experienced HoLEP surgeon resulted in longer operative times, potentially reflecting an initial learning curve, but essentially eliminated the need for open cystotomy. Perioperative results including catheter reinsertion rate and bleeding complications were similar between the two cohorts. These data support continued use of the EAR technique for HOLEP to minimize risk of open conversion.

Racial, ethnic, and socioeconomic disparities in rates of stage IV prostate cancer after USPSTF category "D" recommendation against prostate-specific antigen screening: a retrospective cohort study.

Background: In 2012 the United States Preventative Services Task Force (USPSTF) changed its prostate-specific antigen (PSA) screening recommendation to a category "D". The purpose of this study is to examine racial, ethnic, and socioeconomic differences in risk of presentation with metastatic prostate cancer (mPCa) at time of diagnosis before and after the 2012 USPSTF category "D" recommendation. Methods: This is a population-based cohort study. We identified patients with mPCa at diagnosis within the National Cancer Database from 2004-2017. Logistic regression models were used to examine associations of mPCa with age, race, ethnicity, geographic location, education level, income, and insurance status. Linear regression models assuming underlying binomial distribution were fitted to annual percentage of mPCa at diagnosis for years 2012-2017 to evaluate the post category "D" recommendation era. Results: From 2004 to 2017, 88,987 patients presented with mPCa. A higher percentage of mPCa was noted post-USPSTF category "D" recommendation, with a disproportionately greater increase observed among Hispanics and non-Hispanic Blacks [Δslope/year: Hispanics (0.0092), non-Hispanic Blacks (0.0073) and non-Hispanic Whites (0.0070)]. Insurance status impacts race/ethnicity differently: uninsured Hispanics were 3.66 times more likely to present with mPCa than insured Hispanics, while uninsured non-Hispanic Blacks were 2.62 times more likely to present with mPCa than insured non-Hispanic Blacks. Household income appears to be associated with differences in mPCa, particularly among non-Hispanic Blacks. Those earning <$30,000 were more likely to present with mPCa compared to higher income brackets. Conclusions: Since the USPSTF grade "D" recommendation against PSA screening, the percentage of mPCa at diagnosis has increased, with a higher rate of increase among Hispanic and non-Hispanic Blacks compared to non-Hispanic Whites.

Urinary Outcomes After Magnetic Resonance Imaging-Guided Whole-Gland Transurethral Ultrasound Ablation for Prostate Cancer: Comparison of Suprapubic Tube to Indwelling Urethral Catheter.

Background: MRI-guided transurethral ultrasound ablation (TULSA) is under investigation for whole-gland ablation of low- and intermediate-risk prostate cancer. The ideal method for post-TULSA bladder drainage through postoperative suprapubic tube (SPT) vs indwelling urethral catheter (UC) has not been established. The objective of this study was to evaluate urinary outcomes after whole-gland TULSA, comparing postoperative SPT with UC. Materials and Methods: Two-institution retrospective analysis of whole-gland TULSA for men with grade group 1 and 2 prostate cancer. One institution placed SPT at the time of TULSA with clamp trials (day 10) and removal once voiding. The second placed UC until void trial (day 7). Outcomes included the International Prostate Symptom Score (IPSS), urinary bother score, catheter reinsertion, stricture, clean intermittent catheterization (CIC), and incontinence. Results: Forty-five patients (median age 67) were analyzed. The UC cohort (N = 26) was older (p = 0.007) than the SPT cohort (N = 19) but with similar baseline prostate volumes, IPSS, and urinary bother scores. Patients receiving UC had fewer days with catheter (p = 0.013). Although UC patients suffered more lower urinary tract symptoms at 1-month post-TULSA, there was no significant difference between IPSS scores at baseline and 6 months after surgery regardless of urinary management strategy, although the UC group noted significantly decreased urinary bother. Rates of infection were similar between groups. Six strictures were observed overall, with more in the SPT group, although the difference was not significant (4/19 [21.1%] SPT; 2/26 [7.7%] UC). At 6 months, incontinence rates were low and similar between groups (2/19 [10.5%] SPT; 4/26 [15.4%] UC) and only one patient (UC) required CIC. Conclusions: Our overall findings suggest that SPT and UC are both acceptable options for postoperative bladder drainage after whole-gland TULSA, with statistically similar rates of urinary complications but a slightly different side effect profile.

Tranexamic Acid Was Not Associated With a Reduction in Bleeding Complications Related to Holmium Laser Enucleation of the Prostate.

OBJECTIVE: To compare outcomes in males given perioperative tranexamic acid (TXA) during holmium laser enucleation of the prostate (HoLEP) to a historical cohort that did not receive TXA. METHODS: Our cohort included HoLEP patients (N = 1037) from August 2018 through November 2022. Exclusion criteria included history of stroke, transient ischemic attack, or coronary stent placed within 18 months. The primary predictor was TXA during HoLEP. The primary outcome variable was a return to the operating room (RTOR) for bleeding. Secondary outcomes included catheter reinsertion, transfusion, and clotting complications. Multivariable models evaluating associations of TXA with outcomes were adjusted for potential confounders. RESULTS: In our cohort, 214/1035 had one or more complications with 81 having a Clavien-Dindo Grade of 3a or higher, 114/1037 with catheter reinsertion, 36/1037 RTOR for bleeding, and 15/1035 had a transfusion. TXA use was not associated with 30-day RTOR. 3.7% of those without TXA had a RTOR, and 3.1% of those with TXA had a RTOR (adjusted odds ratio 0.63, 95% CI 0.28-1.38, P = .25). Transfusion rates were higher for those without TXA (2.0%) compared to with (0.5%). This was statistically significant after adjustment (adjusted odds ratio 0.13, 95% CI 0.03-0.69, P = .016) and after correction for multiple testing (corrected P = .048). TXA use was not associated with catheter reinsertion or clotting complications. CONCLUSION: Routine perioperative intravenous TXA in HoLEP patients was not associated with a reduction of RTOR for bleeding, catheter reinsertion, or clotting complications. TXA was associated with decreased transfusions with a low overall event rate of 1.4%.

Utilizing Preoperative Magnetic Resonance Imaging to Self-assess Enucleation Ratio in Holmium Laser Enucleation of the Prostate.

OBJECTIVE: To determine if transition zone (TZ) volume as measured by magnetic resonance imaging (MRI) correlates closely with specimen weight and postoperative prostate-specific antigen (PSA) and to determine if this correlation improved with increased experience. We hypothesize that information from a preoperative MRI can be leveraged to self-assess competency in holmium laser enucleation of the prostate (HoLEP). METHODS: From August 2018 to June 2021 567 men were identified who underwent HoLEP by a single surgeon and had their data entered into a database. Ninety-seven men were identified who had an MRI in our image archives. A radiologist blinded to the specimen weight measured the transition zone (TZ) using image analysis software. TZ volume was then correlated with specimen weight for the entire study period and subdivided into four consecutive periods. Preoperative and Postoperative PSA data was analyzed. RESULTS: Seventeen percent of men who underwent HoLEP at our institution had an MRI preoperatively. The TZ to total prostate volume ratio was 70%. The overall correlation coefficient between TZ volume and specimen weight was 0.914 (P-value <.001). There was no statistically significant improvement in correlation coefficient over time when divided into four equal subgroups. Median PSA reduction was 91% (7.9-0.7 ng/dL). CONCLUSION: Preoperative MRI derived TZ volume correlates closely with specimen weight. We present a reference cohort from a high volume HoLEP center to facilitate HoLEP learners to self-assess competency. Lack of increased correlation over time is likely due to an experienced HoLEP surgeon who is on the flatter portion of his learning curve.

Prostatic urethral lift (PUL) clip causing postoperative pain after holmium laser enucleation of the prostate (HoLEP).

Few series exist in the literature of holmium laser enucleation of the prostate (HoLEP) after prostatic urethral lift (PUL). Even less well known are potential complications seen after a patient undergoes PUL followed by HoLEP. We present our case of a unique clinical finding of a PUL clip and suture found in the urethra of a patient after HoLEP.

Analysis of Operating Room Efficiency During Robot-Assisted Urologic Surgeries Utilizing Fixed (Nonprocedural) Operative Times.

Objective: To analyze operating room (OR) efficiency by evaluating fixed OR times for three common urologic robot-assisted procedures. Methods: Over a 24-month period, we prospectively collected intraoperative data for 635 consecutive robot-assisted surgeries. Fixed (nonprocedural) OR times were evaluated for robot-assisted partial nephrectomy (RAPN) (n = 146), robot-assisted radical cystectomy (RARC) (n = 77), and robot-assisted radical prostatectomy (RARP) (n = 412). Fixed OR times were defined as nonprocedural time in the OR, including in-room time to anesthesia release time (IRAT), anesthesia release to cut time (ARCT), in-room time to cut time (IRCT; IRAT+ARCT), and close time to wheels out time (CTWO). The effects of operation time of day and the number of anesthesia personnel (AP) present in procedure on fixed OR times were also analyzed. Results: Fixed OR times occupied 15.1% (IQR: 12.9%-17.1%) (RARC), 26.6% (22.9%-30.8%) (RAPN), and 20.1% (17.4%-23.1%) (RARP) of total OR time. Time of day did not have a negative effect on fixed OR times for robotic urologic surgeries. Median AP count was highest for RARC (median: 3 and range: 1-7). We did not find any association between AP count and fixed OR times for any of the procedures (p ≥ 0.19). Conclusions: Fixed OR times made up a significant percentage of total OR time for robot-assisted procedures and should be incorporated into OR efficiency analyses. The number of AP per case and time of day of procedure did not negatively impact fixed OR times in urologic robotic surgeries.

Impact of Severe Acute Respiratory Syndrome Coronavirus 2-Induced COVID-19 on Fixed Operating Room Times in Urologic Operations.

Objective: To evaluate the impact of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, on operating room (OR) efficiency for urologic procedures using the concept of fixed OR times. Patients and Methods: Over a 24-month period, urology OR data were prospectively collected. Operations were divided into fixed and variable time points. The fixed OR times were in-roomw to anesthesia-release time, anesthesia-release to cut time, in-room to cut time, and close to wheels-out time. Data from January 1, 2019, to December 31, 2019, were pre-COVID-19 data, and data from April 1, 2020, to December 31, 2020, were post-COVID-19 data. Operations were grouped into endoscopic, implant, major open, and robotic-assisted cases. In the post-COVID-19 era, all patients had a negative polymerase chain reaction test result within 48 hours of operation. The Wilcoxon rank sum test was used to compare the fixed OR times between the pre- and post-COVID-19 eras. Results: A total of 3189 procedures were evaluated: 2058 endoscopic operations (1124 in the pre-COVID-19 era and 934 in the post-COVID-19 era), 343 implant procedures (192 in the pre-COVID-19 era and 151 in the post-COVID-19 era), 222 major open procedures (119 in the pre-COVID-19 era and 103 in the post-COVID-19 era), and 566 robotic-assisted procedures (338 in the pre-COVID-19 era and 228 in the post-COVID-19 era). There were no fixed OR times in any of the examined groups that were negatively impacted by COVID-19. The percentage of the total OR time occupied by fixed OR variables in the pre-COVID-19 era was 40.6% for endoscopic operations, 41.1% for implant procedures, 29.8% for major open procedures, and 21.8% for robotic-assisted procedures. Conclusion: A substantial portion of the total OR time includes fixed time points. Furthermore, COVID-19 did not have a negative impact on fixed OR times in a negative testing environment. Urologic OR efficiency should be maintained in the post-COVID-19 era.

Analysis of Holmium Laser Enucleation of Prostate Fixed Operating Room Times.

OBJECTIVE: To evaluate factors influencing fixed operating room time during holmium laser enucleation of the prostate. MATERIALS AND METHODS: A prospective observational study was performed for all holmium laser enucleation of the prostate (HoLEP) cases performed by a single surgeon over a 24-month period. Operating room (OR) time was divided into fixed and variable time. The variable time was defined as cut-to-close time. Fixed time included in room time to anesthesia release time (IRAT), anesthesia release time to cut time (ARCT), and close time to wheels out (CTWO). The effects of time of day and anesthesia personnel (AP) changes on fixed operating room time were evaluated. RESULTS: A total of 406 HoLEPs were analyzed. There was no statistically significant difference in nonprocedural OR times between morning and afternoon surgeries (IRAT, P = .38, ARCT P = .10, CTWO P = .77). Median nonprocedural OR times accounted for 27% (IQR: 22%-31%) of the total procedure time in the AM group and 29% (IQR: 24%-33%) in the PM group (P = .005). Of the HoLEPs,78.1% (178/228) experienced one or more AP changes during the procedure. The median fixed OR time was not significantly different between procedures with 1 AP and procedures with ≥2 APs (IRAT, P = .53; ARCT, P = .71; CTWO, P = .98). CONCLUSION: Fixed operating room time makes up a significant portion of HoLEP procedures and should be considered when evaluating OR efficiency. The time of day and number of anesthesia personnel involved did not affect the fixed OR times.

Does MOSES pulse modulation reduce short-term catheter reinsertion following holmium laser enucleation of the prostate?

PURPOSE: Previously published studies have shown small prostate size, capsular perforation and intraoperative bladder distension are associated with failed trial without a catheter (TWOC) after HoLEP. The study objective was to determine the relationship between MOSES pulse modulation versus standard laser technology and short-term catheter reinsertion following failed TWOC. MATERIALS AND METHODS: The study included 487 patients who underwent HoLEP, using standard holmium laser settings (180 patients) or MOSES pulse modulation (255 patients), between August 2018 and February 2021. Catheter reinsertion defined as reinsertion following failed TWOC within 30 days of surgery. Association of pulse modulation with catheter reinsertion was examined using single and multivariable logistic regression models. Comparisons of pre and intraoperative characteristics between patients treated without and with pulse modulation were made using a Wilcoxon rank sum test for numeric characteristics or Fisher's exact test for categorical characteristics. RESULTS: Short-term catheter reinsertion occurred in 14% (26/180) of the standard laser setting group as compared with 10% (24/252) of the pulse modulation group. There was no statistically significant association with short-term catheter reinsertion in single (unadjusted OR [standard settings vs. pulse modulation], 1.60; 95% CI, 0.80-2.91; p=0.12) or multivariable analysis adjusting for specimen weight and operative time (adjusted OR [standard settings vs. pulse modulation], 1.44; 95% CI, 0.77-2.68; p=0.25). CONCLUSIONS: In this study, we found no association between post-HoLEP short-term catheter reinsertion following failed TWOC and MOSES pulse modulation. Although MOSES pulse modulation offers several well-documented advantages, catheter reinsertion events appear to be attributable to other factors.

Morphologic Factors Associated With Open Conversion During Holmium Laser Enucleation of the Prostate.

OBJECTIVE: To determine if there is an association between patient body habitus as measured by body mass index (BMI), body surface area (BSA), preoperative prostate volume, postoperative specimen weight, and open conversion with cystotomy or perineal urethrotomy (PU) during holmium laser enucleation of the prostate (HoLEP). We attempt to provide meaningful criteria to assist in preoperative patient counseling. MATERIALS AND METHODS: Three hundred consecutive patients underwent HoLEP between August 3, 2018 and February 20, 2020 by a single surgeon. Patient metrics were recorded in a database including age, height, weight, preoperative prostate volume, postoperative specimen weight, catheter dependence, and transfusion requirement. Nine patients were identified who had cystotomy (8) or PU (1) performed during HoLEP secondary to inability to complete the procedure using standard endoscopic technique. Univariate and multivariate statistical analysis was performed. RESULT: Younger age, higher BMI, higher BSA, and higher estimated prostate volume were associated with increased risk of open conversion during HoLEP. No patient with a BMI under 30 required open conversion. CONCLUSION: Men with BMI >30 kg/m2 or preoperative prostate volume >125 mL should be counseled on the possibility of open conversion with cystotomy or PU. Although the overall risk of conversion is low (3%), the risk may be as high as 10% for patients in the highest quartile of BMI (>30.5 kg/m2) and BSA (>2.2m2).

Factors Predisposing to Catheter Reinsertion Following Holmium Laser Enucleation of the Prostate.

OBJECTIVE: To determine if preoperative catheter dependence or specimen weight is associated with failed trial without catheter (TWOC) following holmium laser enucleation of the prostate (HoLEP). MATERIAL AND METHODS: The study population consisted of 143 consecutive men who underwent HoLEP by a single surgeon over 10 months. Ten were excluded from analysis because they did not have a TWOC on the morning following surgery. Preoperative catheter dependence and specimen weight as well as catheter reinsertions were analyzed. RESULTS: Of 133 men included in analysis, 23 (17.3%) required catheter reinsertion. Of the 23 requiring catheter reinsertion, 6 were catheter dependent preoperatively and 17 were not. Men who were catheter dependent had a lower overall rate of failed TWOC compared to those who were not catheter dependent (15.0% vs 18.3%, P = .647). Mean specimen weight for men requiring catheter reinsertion was significantly lower than men who passed their TWOC (49.9 gm vs 73.1 gm, P = .013). CONCLUSION: Very few studies exist on factors associated with short-term catheter reinsertion following HoLEP or other prostatic hyperplasia procedures. We hypothesized that preoperative catheter dependence and small specimen weight would predispose to catheter reinsertion. Specimen weight was inversely related to risk of catheter reinsertion after HoLEP and preoperative catheter dependence was not associated with catheter reinsertion. In men with small prostates, consideration should be given to delayed TWOC to allow resolution of capsular edema and accumulation of clot in the prostatic fossa. Transition zone volume below which delayed TWOC should be considered is the subject of future studies.

Holmium Laser Enucleation of the Prostate After Failed UroLift: Surgical Considerations for the Management of Nonabsorbable Implants.

OBJECTIVE: To demonstrate the surgical considerations for managing retained UroLift implants when performing HOLEP. Prostatic Urethral Lift via the UroLift System has become a common treatment modality to manage symptoms associated with benign prostatic hyperplasia. The UroLift procedure uses nonabsorbable implants to retract obstructing prostate lobes. Retreatment rates following UroLift have been reported at 13.6% over 5 years.1 We anticipate an increasing number of men seeking definitive surgical management after failed UroLift. There have been reports in the literature of UroLift implants causing morcellator device jams when attempting holmium laser enucleation of the prostate (HOLEP).2 METHODS: From August 2018 to April 2019, we reviewed 118 consecutive patients who underwent HOLEP by a single surgeon. Three men were identified who had previously undergone UroLift. Video footage was obtained. As demonstrated in the video, during enucleation, the metallic clip of the UroLift implants were incorporated in the adenoma specimen. For morcellation, we use the Piranha morcellator (Richard Wolf, Knittlingen, Germany). Morcellation was carried out in a slow and controlled manner. When the metal clip comes into contact with the morcellator, a catch and release is performed by releasing the morcellator pedal and withdrawing the morcellator into the nephroscope to release the adenoma. Remnant clips and sutures can be retrieved with a grasper. We perform a 3 month follow-up cystoscopy in the office to exclude any remnant implant material in the prostatic urethra or bladder. RESULTS: Procedures were completed uneventfully. In developing this technique, we experienced jamming of the morcellator blades in 2 cases requiring replacement of the disposable blades. Follow up in-office cystoscopy did not reveal any remnant implant material that needed to be removed. CONCLUSION: HOLEP can be performed safely in the UroLift failure patient population. Careful morcellation techniques can decrease the risk of costly morcellator blade replacement.

Time-dependent variations in inflammation and scar formation of six different pubovaginal sling materials in the rabbit model.

OBJECTIVES: To provide pathologic evidence, using six different sling materials, of the findings from rabbit model studies demonstrating loss of tensile strength and stiffness in porcine and cadaveric sling materials. METHODS: Ten rabbits randomized into two survival groups (6 and 12 weeks of age) each had human cadaveric fascia, porcine dermis, porcine small intestine submucosa, polypropylene mesh, and autologous fascia implanted on their anterior rectus fascia. At harvest, hematoxylin-eosin and immunohistochemical staining for CD3, CD20, and MIB-I were performed. A pathologist unaware of the content of the slides quantified the degree of inflammation and fibrosis of each. RESULTS: Significant differences were found for inflammation (P = 0.016), eosinophil infiltrate (P = 0.035), and inflammatory rind (P = 0.027) at 12 weeks, with polypropylene mesh having the lowest degree. At 12 weeks, differences were found in the presence of fibrosis/scar formation (P = 0.010) and degree of fibrosis/scar (P = 0.009). Although polypropylene mesh, cadaveric fascia, and porcine dermis all demonstrated a high presence of fibrosis/scar, polypropylene mesh had the greatest overall degree of scar formation at 12 weeks. CONCLUSIONS: The inflammation with the cadaveric fascia and porcine materials may cause rapid clinical deterioration compared with autologous fascia and polypropylene mesh. These data provide a possible explanation for prior biomechanical studies demonstrating variations in tensile strength and stiffness of the different materials. The fibrosis and scarring noted with polypropylene mesh may also contribute to a more lasting repair.

Time dependent variations in biomechanical properties of cadaveric fascia, porcine dermis, porcine small intestine submucosa, polypropylene mesh and autologous fascia in the rabbit model: implications for sling surgery.

PURPOSE: We investigated time dependent variations in tensile strength, stiffness, shrinkage and distortion in 6 materials commonly used for transvaginal anti-incontinence surgery. MATERIALS AND METHODS: A total of 15 rabbits were randomized into 3 survival groups (2, 6 and 12 weeks, respectively). Each rabbit had human cadaveric fascia, porcine dermis, porcine small intestine submucosa, polypropylene mesh and autologous fascia implanted on the anterior rectus fascia. At harvest tensiometry and image analysis were performed on each sling. Results were compared to baseline for each sling type and the percent decrease from baseline was compared among sling types. RESULTS: Each type of human cadaveric fascia and porcine allografts showed a marked decrease (60% to 89%) in tensile strength and stiffness from baseline. Polypropylene mesh and autologous fascia did not differ in tensile strength from baseline. Polypropylene mesh increased in stiffness from baseline. Autologous fascia and small intestinal submucosa demonstrated a 41% and 50% decrease in surface area, respectively, at 12 weeks. CONCLUSIONS: To our knowledge the relative contribution of biomechanical properties of sling material to the success of anti-incontinence surgery is unknown. However, rapid loss of tensile strength and stiffness in porcine and cadaveric materials may contribute to the early re-emergence of symptoms following successful sling surgery. The results of this study add scientific validity to the increasing use of synthetics in anti-incontinence surgery. Urologists selecting a sling material should be aware of its time dependent biomechanical fate relative to other sling materials.