Using uniaxial tensile testing to evaluate the biomechanical properties of bladder tissue after spinal cord injury in rat model.

To investigate the biomechanical properties of rat bladder tissue after spinal cord injury (SCI) using uniaxial tensile testing. Evidence suggests the bladder wall undergoes remodeling following SCI. There is limited data describing the biomechanical properties of bladder wall after SCI. This study describes the changes in elastic and viscoelastic mechanical properties of bladder tissue using a rat model after SCI. Seventeen adult rats received mid-thoracic SCI. Basso, Beattie, and Bresnahan (BBB) locomotor testing was performed on the rats 7-14 days after injury quantifying the degree of SCI. Bladder tissue samples were collected from controls and spinal injured rats at 2- and 9-weeks post-injury. Tissue samples underwent uniaxial stress relaxation to determine instantaneous and relaxation modulus as well as monotonic load-to failure to determine Young's modulus, yield stress and strain, and ultimate stress. SCI resulted in abnormal BBB locomotor scores. Nine weeks post-injury, instantaneous modulus decreased by 71.0% (p = 0.03) compared to controls. Yield strain showed no difference at 2 weeks post-injury but increased 78% (p = 0.003) in SCI rats at 9 weeks post-injury. Compared to controls, ultimate stress decreased 46.5% (p = 0.05) at 2 weeks post-injury in SCI rats but demonstrated no difference at 9 weeks post-injury. The biomechanical properties of rat bladder wall 2 weeks after SCI showed minimal difference compared to controls. By week 9, SCI bladders had a reduction in instantaneous modulus and increased yield strain. The findings indicate biomechanical differences can be identified between control and experimental groups at 2- and 9-week intervals using uniaxial testing.

Impact of caudal block on revision rates after hypospadias repair: Multi-institution review.

INTRODUCTION: There is controversy surrounding the association between caudal block and complication rates after hypospadias repair. Conflicting results have been reported mostly from single-center, low volume studies and those that did not include relevant variables. OBJECTIVES: We hypothesized that caudal block is not associated with increased rates of reoperation after primary repair and is associated with more complex hypospadias surgery. STUDY DESIGN: The Clinical Practice Solutions Center database was queried to identify patients who received a primary hypospadias repair between 2009 and 2010. Primary hypospadias repair was further categorized as meatal advancement and glanduloplasty, distal, one-stage proximal, or one-stage perineal repair. Anesthesia coding was evaluated to identify those who received a caudal block. Any revision surgery was captured between 2009 and 2019 and the types of revision surgeries were identified. Variables such as caudal block, age, insurance type, surgeon volume, and surgeon years in practice were analyzed with mixed effects multiple logistic regression models. RESULTS: The dataset query identified 3343 pediatric males who had primary hypospadias repair. The procedures were performed by 50 surgeons at 27 hospitals. Primary surgeries included meatal advancement and glanduloplasty (23%), distal (69%), proximal (6.9%), and perineal repairs (1%). Caudal block was administered to 42% of patients. Utilization of caudal block was not associated with type of primary surgery (p = 0.21). Adjusting for all other variables, increased patient age was associated with decreased usage of caudal block (p < 0.001). Analysis did not demonstrate a statistically significant association between utilization of caudal block with rates of revision surgery. CONCLUSIONS: This large, multi-institution study demonstrates that the use of caudal block was not associated with more complex hypospadias surgery nor statistically significantly associated with increased rates of revision surgery after primary hypospadias repair.

Autologous regeneration of blood vessels in urinary bladder matrices provides early perfusion after transplant to the bladder.

Large animal testing and clinical trials using bioengineered bladder for augmentation have revealed that large grafts fail due to insufficient blood supply. To address this critical issue, an in vivo staged implant strategy was developed and evaluated to create autologous, vascularized bioengineered bladder tissue with potential for clinical translation. Pig bladders were used to create acellular urinary bladder matrices (UBMs), which were implanted on the rectus abdominus muscles of rats and pigs to generate cellular and vascular grafts. Rectus-regenerated bladder grafts (rrBGs) were highly cellularized and contained an abundance of CD31-positive blood vessels, which were shown to be functional by perfusion studies. Muscle patterns within grafts showed increased smooth muscle formation over time and specifically within the detrusor compartment, with no evidence of striated muscle. Large, autologous rrBGs were transplanted to the pig bladder after partial cystectomy and compared to transplantation of control UBMs at 2 weeks and 3 months post-transplant. Functional, ink-perfused blood vessels were found in the central portion of all rrBGs at 2 weeks, while UBM grafts were significantly deteriorated, contracted and lacked central cellularization and vascularization. By 3 months, rrBGs had mature smooth muscle bundles and were morphologically similar to native bladder. This staged implantation technique allows for regeneration and harvest of large bladder grafts that are morphologically similar to native tissue with functional vessels capable of inosculating with host bladder vessels to provide quick perfusion to the central area of the large graft, thereby preventing early ischemia and contraction.

Clinical Utility of Gene Expression Classifiers in Men With Newly Diagnosed Prostate Cancer.

PURPOSE: Tissue-based gene expression classifiers (GECs) may assist with management decisions in patients with newly diagnosed prostate cancer. We sought to assess the current use of GEC tests and determine how the test results are associated with primary disease management. METHODS: In this observational study, patients diagnosed with localized prostate cancer were tracked through the Michigan Urological Surgery Improvement Collaborative registry. The utilization and results of three GECs (Decipher Prostate Biopsy, Oncotype DX Prostate, and Prolaris) were prospectively collected. Practice patterns, predictors of GEC use, and effect of GEC results on disease management were investigated. RESULTS: Of 3,966 newly diagnosed patients, 747 (18.8%) underwent GEC testing. The rate of GEC use in individual practices ranged from 0% to 93%, and patients undergoing GEC testing were more likely to have a lower prostate-specific antigen level, lower Gleason score, lower clinical T stage, and fewer positive cores (all P < .05). Among patients with clinical favorable risk of cancer, the rate of active surveillance (AS) differed significantly among patients with a GEC result above the threshold (46.2%), those with a GEC result below the threshold (75.9%), and those who did not undergo GEC (57.9%; P < .001 for comparison of the three groups). This results in an estimate that, for every nine men with favorable risk of cancer who undergo GEC testing, one additional patient may have their disease initially managed with AS. On multivariable analysis, patients with favorable-risk prostate cancer who were classified as GEC low risk were more likely to be managed on AS than those without testing (odds ratio, 1.84; P = .006). CONCLUSION: There is large variability in practice-level use and GEC tests ordered in patients with newly diagnosed, localized prostate cancer. In patients with clinical favorable risk of cancer, GEC testing significantly increased the use of AS. Additional follow-up will help determine whether incorporation of GEC testing into initial patient care favorably affects clinical outcomes.

Repeat Prostate Biopsy Practice Patterns in a Statewide Quality Improvement Collaborative.

PURPOSE: We examined rebiopsies in MUSIC (Michigan Urological Surgery Improvement Collaborative) to understand adherence to guidelines recommending repeat prostate biopsy in patients with multifocal high grade prostatic intraepithelial neoplasia or atypical small acinar proliferation. MATERIALS AND METHODS: We analyzed data on men undergoing repeat biopsy, practice patterns and cancer detection rates. Multivariate regression modeling was used to calculate the proportion of patients undergoing rebiopsy. We used claims data to validate the treatment classification in MUSIC. To understand reasons for not performing rebiopsy we reviewed records of a sample of patients with atypical small acinar proliferation. RESULTS: We identified 5,375 men with a negative biopsy, of whom 411 (7.6%) underwent repeat biopsy. In 718 men with high grade prostatic intraepithelial neoplasia, 350 with atypical small acinar proliferation and 587 with high grade prostatic intraepithelial neoplasia and atypical small acinar proliferation or atypical small acinar proliferation alone at initial biopsy the rebiopsy rate was 20.7%, 42.5% and 55.6%, respectively. The adjusted proportion of patients with rebiopsy in each practice ranged from 0% to 17.2% (p <0.001). The overall cancer detection rate at rebiopsy was 39.3%. It was highest after atypical small acinar proliferation (adjusted probability 0.39, 95% CI 0.30-0.48), and after high grade prostatic intraepithelial neoplasia and atypical small acinar proliferation (adjusted probability 0.50, 95% CI 0.35-0.65). The greatest Gleason 7 or greatest detection rate of 41.1% was found in patients with high grade prostatic intraepithelial neoplasia and atypical small acinar proliferation. Chart review revealed that 45.5% of patients with atypical small acinar proliferation underwent prostate specific antigen testing instead of rebiopsy while 36% failed to undergo rebiopsy despite a recommendation. CONCLUSIONS: Rebiopsy rates vary in Michigan practices with relatively low use in men with high grade prostatic intraepithelial neoplasia and atypical small acinar proliferation or atypical small acinar proliferation alone. Quality improvement strategies should target patients with atypical small acinar proliferation and high grade prostatic intraepithelial neoplasia as they have the highest likelihood of cancer detection.