Comparison of Morphological and Histological Characteristics of Human and Sheep: Sheep as a Potential Model for Testing Midurethral Slings in vivo.

INTRODUCTION: The sheep was evaluated as a potential model for preclinical evaluation of urethral slings in vivo based on: (1) anatomical measurements of the sheep vagina and (2) histological tissue integration and host response to polypropylene (PP) slings. METHODS: Eight female, multiparous sheep were utilized. Three of 8 animals underwent surgery mimicking human tension-free vaginal tape protocols for midurethral slings and were euthanized at 6 months. The following measurements were obtained: vaginal length, maximum vaginal width with retraction, symphysis pubis length, and distance from the pubic bone to incision. Explanted sling samples from sheep and human were stained with hematoxylin and eosin for host reaction assessment. RESULTS: Geometric measurements were similar between humans and sheep. Sheep vaginal anatomy allowed sling placement similar to procedures in human surgeries, and all sheep recovered without problems. Comparative histology between the sheep and human indicated similar host reaction and collagen deposition around implants, confirming suitability of the sheep model for biomaterial response assessment. CONCLUSION: Sheep vaginal length is comparable to humans. Tissue integration and host response to PP slings showed chronic inflammation with rich collagen deposition around the material in both sheep and human specimens, highlighting the sheep as a potential animal model for preclinical testing of midurethral slings.

A new titanium-covered transobturator tape for surgical treatment of stress urinary incontinence.

INTRODUCTION AND HYPOTHESIS: To assess the long-term satisfaction, cure rate and safety of a new titanium-covered transobturator tape compared to polypropylene tape for the treatment of stress urinary incontinence (SUI). METHODS: A prospective study was conducted with 151 patients. Seventy patients underwent transobturator sling surgery with titanium tape from 2011 to 2019, and a historical control group (CG) of 81 patients was treated with a noncoated tape and underwent incontinence surgery from 1999 to 2009. We compared patient-reported outcome measures (PROMs) with the incontinence outcome questionnaire (IOQ). RESULTS: The median follow-up was 2½ years in both groups. Based on responses to the IOQ, a statistically significantly shorter time of recovery (IOQ 15: 21.3 ± 26.4 [TG], 40.2 ± 38.5 [CG], p = 0.02), improvement of sex life (IOQ 13: 34.1 ± 29.4 [TG] vs. 65.3 ± 35.6 [CG], p = 0.01) and less voiding dysfunction (IOQ 19: 30.9 ± 28.1 [CG], 9.3 ± 18.6 [TG], p = 0.01) were observed in the TG. Objectively, no postoperative urinary retention was observed in the TG, but four cases were described in the CG. Ten patients needed a reoperation for SUI in the CG compared to three in the TG (p = 0.03). CONCLUSION: The titanium-covered transobturator sling had superior recovery time, improved sexual function and reduced reoperation rate compared to a historical polypropylene group.

Development of bioabsorbable zinc-magnesium alloy wire and validation of its application to urinary tract surgeries.

PURPOSE: Metallic medical devices are typically constructed from non-bioabsorbable metals that remains in the body and causes considerable complications. Particularly in the urinary tract, calculus, intractable infection, and misdiagnosis as calculus are often caused by non-bioabsorbable metals. Here, we developed a zinc-magnesium alloy as a new bioabsorbable metal and sought to evaluate the bioabsorbable behavior of zinc and zinc-magnesium alloy in a rat bladder implantation model. METHODS: We prepared zinc-magnesium alloy wires with various proportions of magnesium and investigated the strength, shape retention, formability, and absorbability of these novel materials. Then, we implanted zinc and zinc-magnesium alloy rings formed by the wires into rat bladder. Rats were euthanized at the end of the observation period, and the rings were removed for volume evaluation. Extracted bladder tissues were subjected to histological analysis. RESULTS: The strength of the zinc wire was enhanced by more than fourfold upon the addition of magnesium, without loss of ductility. Linear reduction of ring volume in urine was observed based on the concentration of magnesium within the ring. Nearly all rings were covered with a thin layer of calculus. Histological findings of the transected urinary bladder tissues did not differ among groups. CONCLUSIONS: Zinc-magnesium alloy is a promising candidate for use as a bioabsorbable medical device in the urinary tract.

Polypropylene and polyvinylidene fluoride transobturator slings for the treatment of female stress urinary incontinence: 1-Year outcomes from a multicentre randomized trial.

AIMS: To compare the effectiveness and safety of polypropylene (PP) and polyvinylidene fluoride (PVDF) transobturator tapes (TOT) for the treatment of female stress urinary incontinence (SUI). METHODS: This is a multicentre randomized trial. Women with SUI or stress-predominant mixed urinary incontinence and scheduled for a TOT procedure were randomized to PP or PVDF slings. The primary outcome was 1-year cure or improvement rate using composite criteria. Complications were also compared. Relationships with outcomes were analyzed using multivariable logistic regressions models. RESULTS: From April 2016 to January 2018 285 participants were randomized. PP and PVDF slings showed similar high cure or improvement rate (91.0% vs. 95.6%, p = .138). Improvement in validated questionnaires was also similar. PVDF slings were associated with a lower rate of de novo urgency incontinence (adjusted odds ratio = 0.35; 95% confidence interval = 0.15-0.80). We found no statistical differences in complications rates, although a higher incidence of long-term pain events were observed in the PP group. The study is underpowered to find differences in specific complications owing to the low number of events. CONCLUSION: PP and PVDF TOTs are equally effective, although PVDF is associated with fewer cases of de novo urgency incontinence. Further studies are needed to give robust conclusions on safety profiles.

Two-year outcomes of surgeon-tailored trans obturator tape for female stress urinary incontinence: a randomized, comparative, trial with traditional trans obturator tape.

BACKGROUND: Previously, we presented the short-term outcomes of surgeon-tailored mesh in patients with SUI undergoing TOT. In this report, we aim to highlight the two-year outcomes of surgeon tailored mesh in terms of subjective and objective cure rates, as well as late complications. METHODS: We performed a randomized, open-label comparative trial that recruited women with SUI who were scheduled to undergo TOT. Eligible patients were randomly allocated in a 1:1 ratio to receive traditional TOT mesh or surgeon-tailored polyethylene mesh. All patients were followed up for two years. RESULTS: At the end of the follow-up, there were 13 women in the traditional TOT mesh group and 14 patients in the surgeon-tailored polyethylene mesh group. Concerning the primary outcome of the present study, the cure rate was 100% in the surgeon-tailored polyethylene mesh (n = 14) and 92.9% in the traditional TOT mesh group (p = 0.39). One woman reported improved symptoms in the traditional TOT mesh group. There were no reported failures in both groups. Concerning safety, the incidence of de novo urgency was 0% in the surgeon-tailored polyethylene mesh group, compared to 7.1% in the traditional TOT mesh group (p = 0.34). None of the women in both groups reported mesh erosions, dyspareunia, or need for reoperation. CONCLUSION: Surgeon-tailored mesh for patients undergoing TOT is a cost-effective technique, which has comparable long-term outcomes, in terms of cure rate and complications, to the traditional costly meshes. Larger multicentre studies should confirm our results.

Ureteral stents: the good the bad and the ugly.

PURPOSE OF REVIEW: Ureteral stents are necessary in the routine practice of an urologist. Choosing the correct stent and being aware of the options available will allow urologists to provide the best possible care for patients and value to the healthcare system. This review seeks to educate urologists regarding improvements in stent technology currently available or in development. RECENT FINDINGS: Research from around the world is underway to discover an ideal stent - one that is comfortable for patients, resists infection and encrustation and is affordable for hospital systems. Stent design alterations and stent coatings are revealing reductions in encrustation and bacterial colonization. Biodegradable stents and magnetic stents are being tested to prevent the discomfort of cystoscopic removal. Intraureteral stents are proving efficacious while eliminating an irritating coil from the bladder and the symptoms associated with it. SUMMARY: The studies highlighted in this review provide encouraging results in the pursuit of the ideal stent while opening discussion around new concepts and further areas of research.

Urethral bulking with Bulkamid: An analysis of efficacy, safety profile, and predictors of functional outcomes in a single-center cohort.

AIMS: The aim of the present work is to analyze the safety profile, effectiveness, and favorable and unfavorable predictors of clinical outcome in urethral bulking with Bulkamid, and to better identify the ideal candidate for the procedure. METHODS: We included all consecutive female patients treated with urethral bulking with Bulkamid at our institution within 2 years. Patients were affected by stress urinary incontinence (SUI) or mixed incontinence. Incontinence severity was classified as "mild" (urinary leakage <50 g/die), "moderate" (50-200 g/die), or "severe" (>200 g/die) at 24-hours pad test. Clinical success was defined as "dry" (no pads); clinical failure included "partial improvement" (>50% 24-hours pad test reduction) and "no benefit" (<50% 24-hours pad test reduction). The χ2 and Mann-Whitney tests were performed to assess the predictors of clinical outcome. RESULTS: The success rate was 36.1% (n = 35). Forty-three patients (44.3%) reported continence improvement. Complications included eight urinary retention cases (8.2%). Statistically significant correlation was observed between incontinence severity and clinical outcome in thee χ2 test (P = .008). No significant correlation was found between functional outcome and urodynamic incontinence features, postoperative urinary retention, previous pelvic surgery, age, and other physiological, pathological, and urodynamics characteristics. Urinary retention following the surgical procedure appeared to be related to clinical success with nonsignificant P value (P = .10). CONCLUSIONS: Bulkamid procedure could be proposed with good results in elderly patients or in patients requiring a low-invasive procedure with low risk of complications, affected either by SUI or mixed incontinence and with mild to moderate incontinence. Previous training to clean intermittent self-catheterization maneuver should be performed.

Efficacy and safety of non-ablative vaginal erbium:YAG laser treatment as a novel surgical treatment for overactive bladder syndrome: comparison with anticholinergics and ß3-adrenoceptor agonists.

PURPOSE: To examine the efficacy and safety of non-ablative vaginal erbium:YAG laser (VEL) for the treatment of overactive bladder syndrome (OAB) compared with those of two other common pharmacotherapies, namely, anticholinergics and ß3-adrenoceptor agonists. METHODS: Female subjects aged 60-69 years who presented with symptoms of OAB from 2015 to 2017 were assigned to three groups (n = 50) receiving treatment with an anticholinergic agent (4 mg fesoterodine), a ß3-adrenoceptor agonist (25 mg mirabegron), or VEL (20 min/session of VEL performed thrice). The OAB symptom score (OABSS), Vaginal Health Index Scale (VHIS), and occurrence of adverse effects were examined prior to and at 1 year following treatment initiation. RESULTS: The three groups showed significant improvement (p < 0.001) for all items of the OABSS questionnaire. Improved VHIS scores were observed only in the VEL group. Furthermore, after VEL treatment, a negative correlation was observed between questions 3 (urinary urgency) and 4 (urgency urinary incontinence) of the OABSS and VHIS. Regarding safety, no adverse events were observed in the VEL group. However, subjects in the other two groups complained of constipation, as indicated by the Constipation Assessment Scale scores, and mouth dryness. The therapeutic effects were inadequate for one and two subjects in the VEL and ß3-adrenoceptor agonist groups, respectively. CONCLUSIONS: VEL safely and effectively improved OABSS through a different mechanism than that involved in pharmacotherapy. We propose the use of VEL as a novel surgical treatment option in the field of urology.

Bulking for stress urinary incontinence in men: A systematic review.

AIMS: An updated literature review on outcomes in men treated with currently commercially available bulking agents was performed to determine whether this is a reasonable option in selected patients. METHODS: The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework of systematic reviews. A comprehensive search of PubMed, Medline, and Embase was undertaken. Abstracts were independently screened by two investigators to include men with stress urinary incontinence treated with a peri-urethral injection of bulking agents currently available in the market. RESULTS: Only eight original articles met the inclusion criteria. The bulking agents used were Macroplastique in five studies (total 123 patients), Opsys, Durasphere, and Urolastic in one study each (10, 7, and 2 patients, respectively). Only one study was randomized; Macroplastique vs AUS in men with mild or total incontinence. The included populations were heterogeneous and encompassed endoscopic, perineal, abdominal and laparoscopic prostate surgery as well as spinal cord injuries and urethral sphincter insufficiency. Significant dissimilarity was evident for the duration of incontinence (9-108 months), mean volume of bulking agent used (2.3-13.5 mL), number of cushions (1-5), depth and position of the cushions. The outcomes varied significantly, with reported dry rates between 0% and 83%. Outcomes were limited by relatively short follow-up in most studies. CONCLUSION: Following initial enthusiasm and then dismay with collagen-based compounds, sparse and heterogeneous literature data were produced on newer non-migrating and nonabsorbable bulking agents. Some studies have suggested encouraging, if short term outcomes, however, future studies are needed in this field to support recommendations for widespread use.

Is a 10-minute surgical scrub necessary in urologic prosthetic surgery? A randomized study of the effect of a 5- vs 10-minute surgical scrub on bacterial colony counts in the genital skin.

AIMS: To determine the antiseptic efficacy on bacterial colony counts of a 5- vs 10-minute surgical site scrub in urologic surgery. METHODS: A prospective cohort study was conducted in 101 patients presenting for elective urological procedures. Patients were randomized to a 5- or 10-minute groin scrub with Betadine (povidone-iodine). Skin swabs were taken immediately after skin clipping and following routine painting with Betadine. A third swab was taken after the betadine skin scrub. Bacterial colony counts were reported as a number of colony-forming units (CFUs). The primary outcome measure was a quantitative comparison of CFUs in the two arms. RESULTS: Fifty-three patients were randomized to a 5-minute scrub and 48 to a 10-minute scrub. After Betadine painting, CFUs were present in 38% of patients in the 5-minute group (mean, 33.5 CFU) and in 27% of the 10-minute group (mean, 45.4 CFU). Following the surgical scrub, only 7.5% of the 5-minute group and 8.3% of the 10-minute group had a measurable CFU count of greater than or equal to 1, and colony counts were low in both groups (5- minute group: mean, 1.5 CFU; 10-minute group: mean, 2.0 CFU). There was no significant difference in CFUs following a 5- or 10-minute scrub (P = 0.28). CONCLUSIONS: The addition of a surgical skin scrub leads to a fourfold reduction in the skin CFU count compared with Betadine painting. However, there is no difference between the antibacterial effects of a 5- and 10-minute scrub. A 5-minute scrub may be sufficient in urologic prosthetic surgery.

Respiratory measurement using infrared thermography and respiratory volume monitor during sedation in patients undergoing endoscopic urologic procedures under spinal anesthesia.

We aimed to evaluate changes in respiratory pattern after sedation by simultaneously applying a respiratory volume monitor (ExSpiron1Xi, RVM) and infrared thermography (IRT) to patients undergoing spinal anesthesia during endoscopic urologic surgeries. After spinal anesthesia was performed, the patient was placed in a lithotomy position for surgery. Then, we established the baseline of the RVM, and started monitoring the mouth and nose with the infrared camera. SpO2 was continuously measured throughout these processes. Once the baseline was set, 0.05 mg/kg midazolam was administered for sedation. Apnea was defined as cessation of airflow for ≥ 10 s with respiratory rate of < 6 breaths/min; hypopnea was defined as a decrease in oxygen hemoglobin of > 4%, compared to baseline. We measured the time at which apnea was detected by IRT, the time at which hypopnea was detected by RVM, and the time at which hypoxia was detected by SpO2. Twenty patients (age: 68.9 ± 11.2 years, body mass index: 24.2 ± 2.6 kg/min2) completed the study. Before sedation, the baseline correlation coefficient of respiratory rate detection between RVM and IRT was 0.866. After midazolam administration, apnea was detected in all subjects within the first 5 min by IRT; the median time required to detect apnea was 102.5 [interquartile range (IQR) 25-75%: 80-155] s. Hypopnea was detected in all subjects within the first 5 min by RVM: the median time required to detect hypopnea was 142.5 (IQR 115-185.2) s. The median time required for SpO2 to decrease > 4% from baseline was 160 (IQR 125-205) s. Our results suggest that IRT can be useful for rapid detection of respiratory changes in patients undergoing sedation following spinal anesthesia for endoscopic urologic procedures.

Challenging the Myth: Transvaginal Mesh is Not Associated with Carcinogenesis.

PURPOSE: We sought to determine if there was a potential link between synthetic polypropylene mesh implantation for transvaginal pelvic organ prolapse and stress urinary incontinence, and carcinogenesis using statewide administrative data. MATERIALS AND METHODS: Women who underwent transvaginal surgery for pelvic organ prolapse or stress urinary incontinence with mesh between January 2008 and December 2009 in New York State were identified using ICD-9-CM procedure codes and CPT-4 codes. Patients in the mesh cohort were individually matched to 2 control cohorts based on comorbidities and procedure date. Carcinogenesis was determined before and after matching at 1, 2 and 3 years, and during the entire followup time. RESULTS: A total of 2,229 patients who underwent mesh based pelvic organ prolapse surgery and 10,401 who underwent sling surgery for stress urinary incontinence between January 2008 and December 2009 were included in the study. Mean followup was 6 years (range 5 to 7). Exact matching between the mesh and control cohorts resulted in 1,870 pairs for pelvic organ prolapse mesh and cholecystectomy (1:2), 1,278 pairs for pelvic organ prolapse mesh and hysterectomy (1:1), 7,986 pairs for sling and cholecystectomy (1:1) and 3,810 pairs for sling and hysterectomy (1:1). Transvaginal mesh implantation was not associated with an increased risk of a cancer diagnosis (pelvic/local cancers or any cancer) at 1 year and during the entire followup of up to 7 years. CONCLUSIONS: Transvaginal surgery with implantation of mesh was not associated with the development of malignancy at a mean followup of 6 years.

Urethral bulking for recurrent stress urinary incontinence after midurethral sling failure.

AIMS: To assess the effectiveness of a polyacrylamide hydrogel (PAHG; Bulkamid®) in treating recurrent stress urinary incontinence (SUI) following a previous midurethral sling (MUS) implant. METHODS: This observational study, conducted since 2009, included 60 patients with recurrent SUI or mixed urinary incontinence (MUI) after a previous MUS and who chose to be treated with PAHG. Objective and subjective outcomes were assessed at 1, 6, and 12 months after the initial injection. Patients were classified as cured based on a negative cough test (supine and standing) and <2 g urine on 1-hr pad test and a VAS score improved by ≥90%. Improved were those with the loss of only a few drops of urine during the cough test and 2-10 g urine on 1-hr pad test or a reduction >50% compared with preoperative urine loss and a VAS score improved by ≥75%. RESULTS: The volume of PAHG injected in the current study ranged from 1-3 ml. Cured/improved rates were 93.3% (56/60), 88.3% (53/60), and 83.6% (46/55) at 1, 6, and 12 months, respectively. Patients with MUI had a cured urgency urinary incontinence rate of 36.8%, 47.4%, and 38.9%, respectively. Voiding dysfunction rates were 13.3% (8/60), 8.3% (5/60), and 1.8% (1/55) at 1, 6, and 12 months and urinary tract infection rates were 5% (3/60), 11.7% (7/60), and 3.6% (2/55), respectively. Other adverse events were short-term and/or observed in <4% of patients. CONCLUSIONS: PAHG can be used to treat recurrent SUI after MUS failure with good outcome and low complication rates. Neurourol. Urodynam. 36:722-726, 2017. © 2016 The Authors. Neurourology and Urodynamics published by Wiley Periodicals, Inc.

Robotic repair of vesicovaginal fistulas using fibrin sealant.

INTRODUCTION: Although infrequent, when encountered vesicovaginal fistulas (VVF) are a difficult condition for both patients and physicians alike. After the first robotic repair was described in 2005, this has been an increasingly common treatment modality. At our institution between 2009 and 2014, eleven of these patients were evaluated and treated with robotic repair. However, fibrin sealant was used in place of the traditional tissue flap. Included are six patients who had previously undergone operative repair. MATERIALS AND METHODS: After IRB approval was obtained, a retrospective study was undertaken to identify patients with VVF. Inclusion criteria were operative repair utilizing a da Vinci robotic system; there were no exclusion criteria. A total of eleven patients were identified, and in each case, a robot assisted laparoscopic approach was utilized and Tisseel fibrin sealant was used in lieu of tissue interposition. RESULTS: All patients underwent successful repair of their VVF without evidence of recurrence at a mean follow up of 15.6 months. CONCLUSIONS: Robotic vesicovaginal fistula repair with fibrin sealant seems to be a safe and viable alternative to the traditional repair utilizing a tissue flap.

[Management of recurrent stress urinary incontinence after anti-incontinence surgery]. / Management recidivující stresové inkontinence moci po selhání efektu anti-inkontinentních operací.

OBJECTIVE: The review article describes the possibilities of procedures for failed anti-incontinence surgery - sling procedure or "bulking agent"? DESIGN: Review article. SETTING: Department of Obstetrics and Gynecology, General Faculty Hospital and 1st Medical Faculty, Charles University, Prague. MATERIALS AND METHODS: The correct choice of procedure type to treat persistent SUI (Stress Urinary Incontinence) which persists or soon reoccurs after anti-incontinence surgery is often problematic. The procedures that treat SUI decrease excessive mobility of the urethra by partially compressing it. If the excessive mobility of the urethra and BN (bladder neck) persist and MUCP (Maximal Urethral Closure Pressure) is within normal range, then we choose a new sling operation to treat the persistent SUI. What type of sling procedure is preferable in this situatitons: transobturator, retropubic or possibly SISs (Single Incision Slings)? SISs are not adequately fixed to the surrounding structures after implantation and are often not of the correct size - especially regarding length - with poor compliance (elasticity). For mentioned reasons we do not use them in reoperations. In this cases we choose such a sling which is properly fixed to the surrounding structures, is of sufficient length, and of appropriate elasticity. When choosing the right type of procedure we also have to consider previous operations: for example, whether reconstructive surgery of pelvic floor defects using mesh has been carried out, where the mesh has been placed, and whether it might be an obstacle to the newly implanted sling. If there is a low urethral mobility after the unsuccessful incontinence operation and a low MUCP is observed on urodynamic examination, then we prefer either a retropubic sling or the application of a bulking agent. The decision of which method to choose also depends on other circumstances, such as whether the patient has undergone radiation treatment or more than on previous surgery to treat SUI. The results of urodynamic, ultrasound and other examinations are very important. CONCLUSIONS: The choice of the right type of surgery to treat SUI after a previous failed procedure depends on information and findings from complex examination of the patient. Case history, examination results, imaging and the experience of the surgeon in individual procedures are therefore most important.

Renal capsule for augmentation cystoplasty in canine model: a favorable biomaterial?

PURPOSE: To evaluate effectiveness of canine renal capsule for augmentation cystoplasty. MATERIALS AND METHODS: Ten adult dogs participated in this study. After induction of anesthesia each animal underwent bed side urodynamic study, bladder capacity and bladder pressure was recorded. Then via mid line incision abdominal cavity was entered, right kidney was identified and its capsule was dissected. Bladder augmentation was done by anastomosing the renal capsule to the bladder. After 6 months bed side urodynamic study was performed again and changes in bladder volume and pressure were recorded. Then the animals were sacrificed and the augmented bladders were sent for histopathology evaluation. RESULTS: Mean maximum anatomic bladder capacity before cystoplasty was 334.00±11.40cc which increased to 488.00±14.83cc post-operatively (p=0.039). Mean anatomic bladder pressure before cystoplasty was 19.00±1.58cmH2O which decreased to 12.60±1.14cmH2O post-operatively (p=0.039). Histopathology evaluation revealed epithelialization of the renal capsule with urothelium without evidence of fibrosis, collagen deposits or contracture. CONCLUSIONS: Our data shows that renal capsule is a favorable biomaterial for bladder augmentation in a canine model.

Whyever bladder tissue engineering clinical applications still remain unusual even though many intriguing technological advances have been reached?

To prevent problematic outcomes of bowel-based bladder reconstructive surgery, such as prosthetic tumors and systemic metabolic complications, research works, to either regenerate and strengthen failing organ or build organ replacement biosubstitute, have been turned, from 90s of the last century, to both regenerative medicine and tissue engineering.Various types of acellular matrices, naturally-derived materials, synthetic polymers have been used for either "unseeded" (cell free) or autologous "cell seeded" tissue engineering scaffolds. Different categories of cell sources - from autologous differentiated urothelial and smooth muscle cells to natural or laboratory procedure-derived stem cells - have been taken into consideration to reach the construction of suitable "cell seeded" templates. Current clinically validated bladder tissue engineering approaches essentially consist of augmentation cystoplasty in patients suffering from poorly compliant neuropathic bladder. No clinical applications of wholly tissue engineered neobladder have been carried out to radical-reconstructive surgical treatment of bladder malignancies or chronic inflammation-due vesical coarctation. Reliable reasons why bladder tissue engineering clinical applications so far remain unusual, particularly imply the risk of graft ischemia, hence its both fibrous contraction and even worse perforation. Therefore, the achievement of graft vascular network (vasculogenesis) could allow, together with the promotion of host surrounding vessel sprouting (angiogenesis), an effective graft blood supply, so avoiding the ischemia-related serious complications.

[Pyeloureteral stenting using nitinol stents].

AIM: To test the effectiveness of nitinol stents in restoring patency of pyeloureteral segment (PUS). MATERIALS AND METHODS: Endoureteral nitinol stents were used in 54 patients. The indications for stenting were recurrent strictures of upper urinary tract and ureteral tumor obstruction in 34 and 20 patients, respectively. In 9 (16.6%) of them, including 4 women and 5 men aged 28-65 years, stenting was performed for extensive recurrent PUS strictures. In 8 patients extensive strictures resulted from various surgical interventions on the PUS. In 2 patients, PUS narrowing was caused by open pyelolithotomy, in 6 patients by pyeloplasty, both open (4) and laparoscopic (2). A female patient with solitary right kidney and Bourneville - Pringle disease of the PUS received two metal prostheses. RESULTS: In all cases, nitinol stents were adequately installed in PUS. Hematuria was observed in 1 patient. During the follow-up period of 8 to 60 months, the results of stenting were considered good in 6 (66.7%) and satisfactory in 2 (22.2%) patients. At month 10, 1 (11.1%) patient developed the stent obstruction by proliferative tissue and underwent ureteroscopy with recanalization of the nitinol stent. The patient with Bourneville - Pringle disease was found to have a stone formed in the renal pelvic end of the endoprosthesis; she underwent percutaneous nephrolithotripsy. In another patient a lower calyceal stone migrated and wedged into the proximal end of the stent. The stone was extracted using percutaneous nephroscopy. CONCLUSION: Pyeloureteral stenting is an effective method to restore patency of the PUS in patients with extensive recurrent strictures. For adequate functioning of the stents, they need to be of optimal length and correctly installed.

[Urinary bladder substitution using combined membrane based on secretions of human mesenchymal stem cells and type I collagen].

AIM: Despite the widespread use of intestinal cystoplasty, urinary bladder substitution remains a challenging problem due to the complexity of operations and the potentially high risk of complications. A promising alternative may be bio-engineered collagen-based matrices containing stem cells or their secretions. MATERIAL AND METHODS: To evaluate the effectiveness of this bladder substitution modality, an experiment was conducted on 14 male rabbits. The animals underwent resection of urinary bladder, and the formed defect was substituted with a membrane of type I collagen (series 1, 5 rabbits) or a membrane of the same composition containing a conditioned medium with secretion of mesenchymal stem/stromal cells derived from human adipose tissue (series 2, 5 rabbits). In the comparison group (4 rabbits) resection of the bladder and the closure of the defect was carried out without bladder substitution (series 3). RESULTS: At 1 month after surgery, there was a complete epithelization of the inner surface of the implant, and body tissues replaced the collagen matrix. In series 1, the collagen implant was replaced mainly by connective tissue ingrown with occasional solitary smooth muscle cells. In series 2, the newly formed bladder wall contained numerous smooth muscle cells, growing into the collagen matrix and forming the muscular coat. In series 3, the muscular layer regeneration at the scar site was also noted, but it was less intense, which was confirmed by morphometry. In series 2, more active vascularization of the collagen implant occurred due to neo-angiogenesis, which was more intense than that in series 3, and especially in series 1. Functional studies revealed a reduced bladder functional capacity in series 1 and 3, while in series 2 it was close to normal. During filling cystometry, changes in intra-vesical pressure profile in series 2 were close to normal, while in series 1 and 3 infusion of a small volume of saline resulted in a marked increase in intra-vesical pressure, showing a reduced compliance of the reconstructed bladder. Discussion The study findings show that implants based on type I collagen can be effectively used to substitute a part of the urinary bladder wall, but bio-engineered collagen matrix grafts containing cell regeneration stimulants secreted by stem cells in their culture medium seem to be more promising.