In vivo response to polypropylene following implantation in animal models: a review of biocompatibility

Injectable Double Crosslinked Hydrogel-Polypropylene Composite Mesh for Repairing Full-Thickness Abdominal Wall Defects

Abdominal wall defects are common clinical diseases, and mesh repair is the standard treatment method. The most commonly used polypropylene (PP) mesh in clinical practice has the advantages of good mechanical properties, stable performance, and effective tissue integration effect. However, direct contact between abdominal viscera and PP mesh can lead to severe abdominal adhesions. To prevent this, the development of a hydrogel-PP composite mesh with anti-adhesive properties may be an effective measure. Herein, biofunctional hydrogel loaded with rosmarinic acid is developed by modifying chitosan and Pluronic F127, which possesses suitable physical and chemical properties and commendable in vitro biocompatibility. In the repair of full-thickness abdominal wall defects in rats, hydrogels are injected onto the surface of PP mesh and applied to intraperitoneal repair. The results indicate that the use of hydrogel-PP composite mesh can alleviate abdominal adhesions resulting from traditional PP mesh implantation by decreasing local inflammatory response, reducing oxidative stress, and regulating the fibrinolytic system. Combined with the tissue integration ability of PP mesh, hydrogel-PP composite mesh has great potential for repairing full-thickness abdominal wall defects.

Polypropylene Pelvic Mesh: What Went Wrong and What Will Be of the Future?

Background: Polypropylene (PP) pelvic mesh is a synthetic mesh made of PP polymer used to treat pelvic organ prolapse (POP). Its use has become highly controversial due to reports of serious complications. This research critically reviews the current management options for POP and PP mesh as a viable clinical application for the treatment of POP. The safety and suitability of PP material were rigorously studied and critically evaluated, with consideration to the mechanical and chemical properties of PP. We proposed the ideal properties of the ‘perfect’ synthetic pelvic mesh with emerging advanced materials. Methods: We performed a literature review using PubMed/Medline, Embase, Cochrane Library (Wiley) databases, and ClinicalTrials.gov databases, including the relevant keywords: pelvic organ prolapse (POP), polypropylene mesh, synthetic mesh, and mesh complications. Results: The results of this review found that although PP is nontoxic, its physical properties demonstrate a significant mismatch between its viscoelastic properties compared to the surrounding tissue, which is a likely cause of complications. In addition, a lack of integration of PP mesh into surrounding tissue over longer periods of follow up is another risk factor for irreversible complications. Conclusions: PP mesh has caused a rise in reports of complications involving chronic pain and mesh exposure. This is due to the mechanical and physicochemical properties of PP mesh. As a result, PP mesh for the treatment of POP has been banned in multiple countries, currently with no alternative available. We propose the development of a pelvic mesh using advanced materials including emerging graphene-based nanocomposite materials.

Transvaginal Mesh-related Complications and the Potential Role of Bacterial Colonization: An Exploratory Observational Study

STUDY OBJECTIVE

This study aimed to investigate the potential role of transvaginal mesh bacterial colonization in the development of mesh-related complications (MRCs).

DESIGN

An observational and exploratory study.

SETTING

Tertiary referral center (Amsterdam UMC, location AMC, Amsterdam, The Netherlands). PATIëNTS: 49 patients indicated for mesh removal and 20 women of whom vaginal tissue was retrieved during prolapse surgery as a reference cohort.

INTERVENTIONS

collection of mesh-tissue complex (patient cohort) or vaginal tissue (reference cohort) MEASUREMENTS AND MAIN RESULTS: Homogenized samples were used for quantitative microbiological culture. Inflammation and fibrosis were semiquantitatively histologically scored; Gram staining and fluorescence in situ hybridization were used to detect bacteria and bacterial biofilms. Of the 49 patients, 44 samples (90%) were culture positive, with a higher diversity of species and more Gram-negative bacteria and polymicrobial cultures in the MRC cohort than the reference cohort, with mostly staphylococci, streptococci, Actinomyces spp., Cutibacterium acnes, and Escherichia coli. Patients with clinical signs of infection or exposure had the highest bacterial counts. Histology demonstrated moderate to severe inflammation in most samples. Gram staining showed bacteria in 57% of culture-positive samples, and in selected samples, fluorescence in situ hybridization illustrated a polymicrobial biofilm.

CONCLUSION

In this study, we observed distinct differences in bacterial numbers and species between patients with MRCs and a reference cohort. Bacteria were observed at the mesh-tissue interface in a biofilm. These results strongly support the potential role of bacterial mesh colonization in the development of MRCs.

Preparation and Characterization of Functionalized Surgical Meshes for Early Detection of Bacterial Infections

Isotactic polypropylene (i-PP) nonabsorbable surgical meshes are modified by incorporating a conducting polymer (CP) layer to detect the adhesion and growth of bacteria by sensing the oxidation of nicotinamide adenine dinucleotide (NADH), a metabolite produced by the respiration reactions of such microorganisms, to NAD+. A three-step process is used for such incorporation: (1) treat pristine meshes with low-pressure O2 plasma; (2) functionalize the surface with CP nanoparticles; and (3) coat with a homogeneous layer of electropolymerized CP using the nanoparticles introduced in (2) as polymerization nuclei. The modified meshes are stable and easy to handle and also show good electrochemical response. The detection by cyclic voltammetry of NADH within the interval of concentrations reported for bacterial cultures is demonstrated for the two modified meshes. Furthermore, Staphylococcus aureus and both biofilm-positive (B+) and biofilm-negative (B-) Escherichia coli cultures are used to prove real-time monitoring of NADH coming from aerobic respiration reactions. The proposed strategy, which offers a simple and innovative process for incorporating a sensor for the electrochemical detection of bacteria metabolism to currently existing surgical meshes, holds considerable promise for the future development of a new generation of smart biomedical devices to fight against post-operative bacterial infections.

Long-term Data on Graft-Related Complications After Sacrocolpopexy With Lightweight Compared With Heavier-Weight Mesh

OBJECTIVE

To estimate the long-term incidence and characteristics of graft-related complications, rate of reintervention for graft-related complications and prolapse, and subjective and anatomical outcomes after laparoscopic sacrocolpopexy with heavier-weight (more than 44 g/m2) compared with lightweight (28 g/m2) polypropylene mesh, the latter with resorbable poliglecaprone component.

METHODS

We conducted a single-center study that compared two consecutive prospective cohorts of patients who were undergoing laparoscopic sacrocolpopexy for symptomatic stage 2 or greater cervical or vault prolapse, by using either heavier-weight polypropylene mesh or lightweight polypropylene mesh at a similar duration of follow-up. The primary outcome was the occurrence of graft-related complications and their nature. Secondary outcomes included reinterventions for graft-related complications, recurrent apical prolapse, a subjective outcome (PGIC [Patient Global Impression of Change] score 4 or higher), and an anatomical outcome (point C -1 cm or greater).

RESULTS

We identified consecutive patients: 101 were implanted with heavier-weight polypropylene, and 238 were implanted with lightweight polypropylene; all were audited at comparable follow-up times (heavier-weight mesh: 97 months [interquartile range 16 months]; lightweight mesh: 92.5 months [interquartile range 58 months]). Graft-related complications were more frequent in patients with heavier-weight than lightweight mesh (22.8% [23/101] vs 7.3% [13/178]; hazard ratio [HR] 3.3, 95% CI 1.6-7.1), more frequently symptomatic (heavier-weight mesh: 16.8% [17/101] vs lightweight mesh: 2.8% [5/178]; HR 6.0, 95% CI 2.5-14.3), and more frequently lead to reintervention for graft-related complications (heavier-weight mesh: 18.8% [19/101] vs lightweight mesh: 2.1% [5/238]; HR 4.6, 95% CI 1.9-11.2). The vast majority of patients improved (PGIC score 4 or higher), without difference between groups (heavier-weight mesh: 71/84 [84.9%]; lightweight mesh: 154/178 [86.5%]; HR 0.8, 95% CI 0.6-1.1); neither was there a difference in anatomical failure rate (heavier-weight mesh: 1/60 [1.7%] vs lightweight mesh: 8/131 [6.1%]; HR 0.3, 95% CI 0.1-1.4). Reoperations for recurrent vault prolapse were scarce (0.0% in heavier-weight mesh, vs 0.4% in lightweight mesh).

CONCLUSION

In two consecutive cohorts, the number of graft-related complications, symptomatic graft-related complications, and reinterventions for graft-related complications were higher in patients implanted with heavier-weight polypropylene than when lightweight polypropylene was used. There were no differences in subjective, objective outcomes, and reoperation rates for prolapse.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT04378400.

FUNDING

To assist in this audit, the University Hospitals Leuven received support from Ethicon Endosurgery.

Clinical Outcomes of Mid-Urethral Sling (MUS) Procedures for the Treatment of Female Urinary Incontinence: A Multicenter Study

Introduction: Stress urinary incontinence (SUI) has a significant impact on the quality of life of many women. Due to embarrassment, most women do not seek medical attention for this condition. The treatment of this problem includes preventive therapies, and in the more advanced stage of urinary incontinence, surgery is a solution. Despite doubts regarding the implantation of urological tapes, the use of tension-free minimally invasive methods constitutes the “gold standard” in the treatment of stress urinary incontinence in women. Objective: The purpose of this article was to evaluate the efficacy and safety of ultralight, polypropylene urogynecological tape (Dallop® NM ULTRALIGHT, Tricomed S.A., Poland) in the surgical treatment of female stress urinary incontinence and mixed urinary incontinence. Methods: This is a multicenter, retrospective cohort study. The included women were adults with stress urinary incontinence (Grade 2 with a positive cough test or Grade 3) or had mixed urinary incontinence and who had undergone “retropubic” or “transobturator” surgery and completed a postoperative follow-up. Results: The study included 68 women from three hospitals. All women completed <6-month and >6-month follow-ups. The median age was 55 (range 36−80). The average value of BMI in the “retropubic” group was 28.6 ± 5.58, and in the “transobturator” group, it was 26.1 ± 4.60. Sixty-three percent (63%, n = 43) of patients were operated on using the “transobturator” method, while thirty-seven percent (37%, n = 25) were operated on using the “retropubic” method. Both the “retropubic” and “transobturator” groups had comparable results in the treatment of SUI. The study showed efficiencies of 84% for the “transobturator” method and 80% for the “retropubic” method. In the “retropubic” group, intraoperative complications were reported in three patients (7%), in comparison to none in the “transobturator” group. There were no tape-related adverse events or infections reported in any case. Conclusions: The presented research confirms the safety and efficacy of retropubic and transobturator tape methods in both short- and long-term follow-up—the success rate was over 80%. In addition to the surgical method used, the experience of the surgeons also has an impact on the final outcome of the surgery. The conducted multi-center study offers the opportunity to eliminate the influence of the human factor on the effectiveness of the procedure.

Ultralight type I transvaginal mesh: an alternative for recurrent severe posterior vaginal prolapse

OBJECTIVE

This study aimed to analyze the medium-term outcomes of ultralight type I mesh for postmenopausal women with recurrent severe posterior vaginal prolapse (PVP).

METHODS

All participants underwent transvaginal ultralight type I mesh repair between April 2016 and April 2021 and were followed until May 2022. Pelvic Organ Prolapse Quantification System (POP-Q) staging, mesh-related complications, Patient Global Impression of Improvement (PGI-I) scale and quality of life questionnaire responses were evaluated. The primary outcome was composite surgical success rate at the last follow-up, composite success being defined as no vaginal bulge symptoms, no POP-Q point at or beyond the hymen and no re-treatment for POP. Secondary outcomes included anatomic outcomes (POP-Q score), symptomatic relief and complications.

RESULTS

The median follow-up was 37.3 months. At the last follow-up, the composite success rate was 75%, and POP-Q scores for the vault and posterior wall and quality of life questionnaire scores were significantly improved (p < 0.01). The subjective satisfaction (PGI-I ≤ 2) rate was 83.3%. There were no mesh-related complications.

CONCLUSIONS

Ultralight mesh can achieve good clinical outcomes and substantially improve the quality of life of patients with severe recurrent PVP in the medium term, and may thus be a viable alternative for treating this condition.

Hydraulic Detrusor for Artificial Bladder Active Voiding

The gold standard treatment for bladder cancer is radical cystectomy that implies bladder removal coupled to urinary diversions. Despite the serious complications and the impossibility of controlled active voiding, bladder substitution with artificial systems is a challenge and cannot represent a real option, yet. In this article, we present hydraulic artificial detrusor prototypes to control and drive the voiding of an artificial bladder (AB). These prototypes rely on two actuator designs (origami and bellows) based either on negative or positive operating pressure, to be combined with an AB structure. Based on the bladder geometry and size, we optimized the actuators in terms of contraction/expansion performances, minimizing the liquid volume required for actuation and exploring different actuator arrangements to maximize the voiding efficiency. To operate the actuators, an ad hoc electrohydraulic circuit was developed for transferring liquid between the actuators and a reservoir, both of them intended to be implanted. The AB, actuators, and reservoir were fabricated with biocompatible flexible thermoplastic materials by a heat-sealing process. We assessed the voiding efficiency with benchtop experiments by varying the actuator type and arrangement at different simulated patient positions (horizontal, 45° tilted, and vertical) to identify the optimal configuration and actuation strategy. The most efficient solution relies on two bellows actuators anchored to the AB. This artificial detrusor design resulted in a voiding efficiency of about 99%, 99%, and 89%, in the vertical, 45° tilted, and horizontal positions, respectively. The relative voiding time was reduced by about 17, 24, and 55 s compared with the unactuated bladder.

Influence of Test Specimen Geometry and Water Soaking on the In Vitro Cytotoxicity of Orthocryl®, Orthocryl® LC, Loctite® EA 9483 and Polypropylene

Depending on their composition, plastics have a cytotoxic potential that needs to be evaluated before they are used in dentistry, e.g., as orthodontic removable appliances. Relevant guidelines set out requirements that a potential new resin in the medical field must meet, with a wide scope for experimental design. In the present study, test specimens of different geometries consisting of varying polymers (Orthocryl^®, Orthocryl^® LC, Loctite^® EA 9483, Polypropylene) were soaked for different periods of time, then transferred to cell culture medium for 24 h, which was subsequently used for 24-h cultivation of A549 cells, followed by cytotoxicity assays (WST-1, Annexin V-FITC-propidium iodide (PI) flow cytometry). In this context, a reduction in the cytotoxic effect of the eluates of test specimens prepared from Orthocryl^® LC and Loctite^® EA 9483 was particularly evident in the Annexin V-FITC-PI assay when the soaking time was extended to 48 h and 168 h, respectively. Consistent with this, a reduced release of potentially toxic monomers into the cell culture medium, as measured by gas chromatography-mass spectrometry, was observed when the prior soaking time of test specimens of all geometries was extended. Remarkably, a significant increase in cytotoxic effect was observed in the WST-1 assay, which was accompanied by a higher release of monomers when the thickness of the test sample was increased from 0.5 to 1.0 mm, although an elution volume adapted to the surface area was used. However, further increasing the thickness to 3.0 mm did not lead to an increase in the observed cytotoxicity or monomer release. Test specimens made of polypropylene showed no toxicity under all test specimen sizes and soaking time conditions. Overall, it is recommended to perform toxicity studies of test specimens using different geometries and soaking times. Thereby, the influence of the different specimen thicknesses should also be considered. Finally, an extension of the test protocols proposed in ISO 10993-5:2009 should be considered, e.g., by flow cytometry or monomer analysis as well as fixed soaking times.

Exploratory safety study of an umbilical cord derived urethral sling in bilateral pudendal nerves injury-induced urinary incontinence in female rats

PURPOSE

Mid-urethral slings are the standard treatment for women with refractory stress urinary incontinence (SUI) but are at risk of infection or erosion due to host-prothesis interaction. In this proof-of-concept study, we aimed at evaluating umbilical vessel sling (UVS) in incontinent female rats.

MATERIAL AND METHODS

UVS was extracted from human umbilical cord lining and was placed on female rats who underwent bilateral pelvic nerve injury (PNI) to reproduce SUI (Group 3, N = 10). Two control groups were also studied: rats with no PNI (Group 1, N = 4) and rats with PNI but no UVS (Group 2, N = 10). Micturition calendar was frequently recorded using a metabolic cage, and leak point pressure (LPP) test was performed on Day 28. After the LPP test, rats were euthanized, and bladder/urethra were collected for histopathological analysis.

RESULTS

Overall, 24 rats were included, of whom 10 had both PNI and UVS placement. Compared with Group 2, Group 3 had increased maximal LPP but the difference did not reach significance (respectively 21.8 ± 2.1 mmHg vs. 28.4 ± 4.1 mmHg, p = 0.2). Micturition frequencies were similar between the groups. Total voided volume was higher in Group 3 at the end of the study compared with Group 2 (12.5 ± 1.1 ml vs. 9.4 ± 0.6 ml, respectively, p < 0.05). Histopathological findings evidenced a good local tolerance and a moderate to high tissue integration of the UVS.

CONCLUSIONS

Biological sling derived from human umbilical vessel could be safely placed with a slight improvement of LPP in a population of rats who had bilateral PNI without major modification of micturition calendar. UVS could be a promising biomaterial in the management of SUI in women. Clinical studies are needed.

Role of Fibroblasts and Myofibroblasts on the Pathogenesis and Treatment of Pelvic Organ Prolapse

Pelvic organ prolapse (POP) is a multifactorial connective tissue disorder caused by damage to the supportive structures of the pelvic floor, leading to the descent of pelvic organs in the vagina. In women with POP, fibroblast function is disturbed or altered, which causes impaired collagen metabolism that affects the mechanical properties of the tissue. Ideal surgical repair, either native tissue repair or POP surgery using an implant, aims to create a functional pelvic floor that is load-bearing, activating fibroblasts to regulate collagen metabolism without creating fibrotic tissue. Fibroblast function plays a crucial role in the pathophysiology of POP by directly affecting the connective tissue quality. On the other hand, fibroblasts determine the success of the POP treatment, as the fibroblast-to-(myo)fibroblast transition is the key event during wound healing and tissue repair. In this review, we aim to resolve the question of “cause and result” for the fibroblasts in the development and treatment of POP. This review may contribute to preventing the development and progress of anatomical abnormalities involved in POP and to optimizing surgical outcomes.

Evaluation of the short-term host response and biomechanics of an absorbable poly-4-hydroxybutyrate scaffold in a sheep model following vaginal implantation

Objective

To evaluate the host‐ and biomechanical response to a fully absorbable poly‐4‐hydroxybutyrate (P4HB) scaffold in comparison with the response to polypropylene (PP) mesh.

Design

In vivo animal experiment.

Setting

KU Leuven Center for Surgical Technologies.

Population

Fourteen parous female Mule sheep.

Methods

P4HB scaffolds were surgically implanted in the posterior vaginal wall of sheep. The comparative PP mesh data were obtained from an identical study protocol performed previously.

Main outcome measures

Gross necropsy, host response and biomechanical evaluation of explants, and the in vivo P4HB scaffold degradation were evaluated at 60‐ and 180‐days post‐implantation. Data are reported as mean ± standard deviation (SD) or standard error of the mean (SEM).

Results

Gross necropsy revealed no implant‐related adverse events using P4HB scaffolds. The tensile stiffness of the P4HB explants increased at 180‐days (12.498 ± 2.66 N/mm SEM [p =0.019]) as compared to 60‐days (4.585 ± 1.57 N/mm) post‐implantation, while P4HB degraded gradually. P4HB scaffolds exhibited excellent tissue integration with dense connective tissue and a moderate initial host response. P4HB scaffolds induced a significantly higher M2/M1 ratio (1.70 ± 0.67 SD, score 0–4), as compared to PP mesh(0.99 ± 0.78 SD, score 0–4) at 180‐days.

Conclusions

P4HB scaffold facilitated a gradual load transfer to vaginal tissue over time. The fully absorbable P4HB scaffold, in comparison to PP mesh, has a favorable host response with comparable load‐bearing capacity. If these results are also observed at longer follow‐up in‐vivo, a clinical study using P4HB for vaginal POP surgery may be warranted to demonstrate efficacy.

Tweetable Abstract

Degradable vaginal P4HB implant might be a solution for treatment of POP.

Degradable vaginal P4HB implant might be a solution for treatment of POP.

The Masquelet Technique: Can Disposable Polypropylene Syringes be an Alternative to Standard PMMA Spacers? A Rat Bone Defect Model

BACKGROUND

Usually, the two-stage Masquelet induced-membrane technique for extremity reconstruction begins with a polymethylmethacrylate (PMMA) cement spacer-driven membrane, followed by an autologous cancellous bone graft implanted into the membrane cavity to promote healing of large bone defects. In exceptional cases, spacers made of polypropylene disposable syringes were successfully used instead of the usual PMMA spacers because of a PMMA cement shortage caused by a lack of resources. However, this approach lacks clinical evidence and requires experimental validation before being recommended as an alternative to the conventional technique.

QUESTIONS/PURPOSES

To (1) develop and (2) validate a critical-sized femoral defect model in rats for two stages of the Masquelet technique and to (3) compare the biological and bone healing properties of polypropylene-induced membranes and PMMA-induced membranes in this model.

METHODS

Fifty male Sprague Dawley rats aged 8 weeks old received a 6-mm femur defect, which was stabilized with an external fixator that was converted into an internal device. In the development phase, the defect was filled with PMMA in 16 rats to determine the most favorable timing for bone grafting. Two rats were excluded since they died of anesthetic complications. The other 14 were successively euthanized after 2 weeks (n = 3), 4 weeks (n = 4), 6 weeks (n = 4), and 8 weeks (n = 3) for induced membrane analyses. In the validation phase, 12 rats underwent both stages of the procedure using a PMMA spacer and were randomly assigned to two groups, whether the induced membrane was preserved or removed before grafting. To address our final objective, we implanted either polypropylene or PMMA spacers into the defect (Masquelet technique Stage 1; n = 11 rats per group) for the period established by the development phase. In each group, 6 of 11 rats were euthanized to compare the biological properties of polypropylene-induced membranes and PMMA-induced membranes using histological qualitative analysis, semiquantitative assessment of the bone morphogenic protein-2 content by immunostaining, and qualitative assessment of the mesenchymal stromal cell (MSC; CD31-, CD45-, CD90+, and CD73+ phenotypes) content by flow cytometry. Quantitative measurements from serum bone turnover markers were also performed. The five remaining rats of each group were used for Masquelet technique Stage 2, in which rat bone allografts were implanted in the induced membrane cavity after the polypropylene or PMMA spacers were removed. These rats recovered for 10 weeks before being euthanized for microCT quantitative measurements and bone histology qualitative assessment to evaluate and compare the extent of bone regeneration between groups.

RESULTS

Induced membrane analyses together with serum bone turnover measurements indicated that a 4-week interval time between stages was the most favorable. Removal of the induced membrane before grafting led to almost constant early implant failures with poor bone formation. Four-week-old rats with polypropylene-triggered induced membranes displayed similar histologic organization as rats with PMMA-driven induced membranes, without any difference in the cell density of the extracellular matrix (4933 ± 916 cells per mm2 for polypropylene versus 4923 ± 1284 cells per mm2 for PMMA; p = 0.98). Induced membrane-derived MSCs were found in both groups with no difference (4 of 5 with polypropylene versus 3 of 3 with PMMA; p > 0.99). Induced membrane bone morphogenic protein-2 immunolabeling and serum bone turnover marker levels were comparable between the polypropylene and PMMA groups. MicroCT analysis found that bone regeneration in the polypropylene group seemed comparable with that in the PMMA group (29 ± 26 mm3 for polypropylene versus 24 ± 18 mm3 for PMMA; p > 0.99). Finally, qualitative histological assessment revealed a satisfactory endochondral ossification maturation in both groups.

CONCLUSION

Using a critical-sized femoral defect model in rats, we demonstrated that polypropylene spacers could induce membrane encapsulation with histologic characteristics and bone regenerative capacities that seem like those of PMMA spacers.

CLINICAL RELEVANCE

In a same bone site, polymers with close physical properties seem to lead to similar foreign body reactions and induce encapsulating membranes with comparable bone healing properties. Polypropylene spacers made from disposable syringes could be a valuable alternative to PMMA. These results support the possibility of a cementless Masquelet technique in cases of PMMA shortage caused by a lack of resources.

Host-biomaterial interactions in mesh complications after pelvic floor reconstructive surgery

Polypropylene (PPL) mesh is widely used in pelvic floor reconstructive surgery for prolapse and stress urinary incontinence. However, some women, particularly those treated using transvaginal PPL mesh placement for prolapse, experience intractable pain and mesh exposure or extrusion. Explanted tissue from patients with complications following transvaginal implantation of mesh is typified by a dense fibrous capsule with an immune cell-rich infiltrate, suggesting that the host immune response has a role in transvaginal PPL mesh complications through the separate contributions of the host (patient), the biological niche within which the material is implanted and biomaterial properties of the mesh. This immune response might be strongly influenced by both the baseline inflammatory status of the patient, surgical technique and experience, and the unique hormonal, immune and microbial tissue niche of the vagina. Mesh porosity, surface area and stiffness also might have an effect on the immune and tissue response to transvaginal mesh placement. Thus, a regulatory pathway is needed for mesh development that recognizes the roles of host and biological factors in driving the immune response to mesh, as well as mandatory mesh registries and the longitudinal surveillance of patients.

Evaluating tissue-engineered repair material for pelvic floor dysfunction: a comparison of in vivo response to meshes implanted in rats

INTRODUCTION AND HYPOTHESIS

Achieving better anatomic restoration and decreasing the associated complications are necessary for material repair of pelvic floor dysfunction (PFD). This study was aimed to investigate host response to tissue-engineered repair material (TERM) in rat models by comparing different materials and study the changes in biomechanical properties over time.

METHODS

TERM was constructed by seeding adipose-derived stem cells (ADSCs) on electrospun poly(L-lactide)-trimethylene carbonate-glycolide (PLTG) terpolymers. The TERM, PLTG, porcine small intestine submucosa mesh (SIS), and polypropylene (PP) (n = 6 / group per time point) were implanted in rats for 7, 30, 60, and 90 days. Hematoxylin-eosin and Masson's trichrome staining were used to assess the host response, and mechanical testing was used to evaluate the changes in biomechanical properties.

RESULTS

In vivo imaging showed that the ADSCs were confined to the abdominal wall and did not migrate to other organs or tissues. The TERM was encapsulated by a thicker layer of connective tissue and was associated with less reduced inflammatory scores compared with PLTG and PP over time. The vascularization of the TERM was greater than that with PP and PLTG over time (p < 0.05) and was greater than that with SIS on day 90. The ultimate tensile strain and Young's modulus of the PP group showed the greatest increases, and the TERM group followed on day 90.

CONCLUSIONS

This TERM achieved better host integration in rat models and better biomechanical properties, and it may be an alternative material for PFD.

Small Intestinal Submucosa Membrane Modified by Fusion Peptide-Mediated Extracellular Vesicles to Promote Tissue Regeneration

Tissue injury, which often occurs in daily life, remains challenging in clinical medicine. Developing a novel biomaterial with the capability to provide an ideal microenvironment and homeostasis around the wound is highly desirable for effective tissue regenerative medicine. The small intestinal submucosa (SIS) membrane possesses a precise spatial structure with excellent biocompatibility. Extracellular vesicles (EVs) derived from umbilical cord mesenchymal stem cells can achieve rapid cell proliferation and migration with little immune response by creating a satisfactory microenvironment. In this study, fusion peptide-mediated EVs are able to modify the surface of the SIS membrane via specific combination. In vitro studies prove that modified SIS membranes can promote cell migration and spreading. This phenomenon may be because of the activation of TEADs, which regulate cell behavior. By constructing a rat abdominal wall defect model, it is further demonstrated that the modified SIS membrane is more conducive to tissue regeneration. Collectively, these results suggest that SIS membranes modified by fusion peptide-mediated EVs achieve excellent biofunction and provide promising prospects for tissue regeneration.

Visualization of implanted mesh in the pelvic reconstructive surgery using an X-ray-detectable thread

PURPOSE

Visualization of the implanted mesh after a pelvic floor repair surgery is important for evaluating mesh-related complications. We made an X-ray-detectable mesh and studied the histocompatibility and toxicity of it.

METHODS

A thin barium sulfate thread was weaved on a traditional polypropylene mesh to make it X-ray detectable. The cytotoxicity of the mesh was tested by the MTT assay on L929 cell line. The histocompatibility and toxicity of mesh were evaluated in rabbits. Meshes were first implanted intraperitoneally. On postoperative day 7, bloods were tested to estimate the acute toxicity of meshes. After 6 months, rabbits were sacrificed and local inflammatory reaction and tissue regeneration at implantation sites were estimated by the HE stain and Masson stain. In addition, CT scans were performed after surgeries to display the location and shape of implanted meshes.

RESULTS

Compared to the polypropylene mesh group, no significant difference was observed in the X-ray-detectable mesh group on both in vitro cytotoxicity and in vivo acute and chronic toxicity. The amounts of extra cellular matrix between two groups did not differ. Through CT scan and 3D remodeling, the barium sulfate thread clearly revealed the position and shape of the X-ray-detectable mesh, whereas the traditional mesh was invisible under CT scan.

CONCLUSION

Adding a thin barium sulfate thread on the polypropylene mesh does not change its histocompatibility or toxicity in rabbit model. The barium sulfate thread can effectively show the location and shape of implanted mesh under CT scan.

Animal experimental research assessing urogynecologic surgical mesh implants: Outcome measures describing the host response, a systematic review and meta-analysis

Aim

Before the introduction of new biomaterials for prolapse surgery, animal studies on the host response are required. Unfortunately, large variation in study design hampers obtaining an overview of the safety and efficacy, and translation to clinical practice. Our aim is to systematically review the literature on all outcome measures describing the host response in animal studies assessing the biocompatibility of urogynecologic surgical mesh implants for prolapse surgery. Furthermore, by meta‐analysis, we aim to assess the effect of implantation and compare this to control animals receiving sham surgery or native tissue repair.

Methods

We performed a systematic search from inception to August 2020. Since this is an explorative study we included original, controlled, and noncontrolled animal studies describing any host response to the implant. Quantitative outcome measures reported ≥10 times in ≥2 articles were eligible for meta‐analysis.

Results

Fifty articles were included in the qualitative synthesis and 36 articles were eligible for meta‐analysis. In total, 154 outcome measures were defined and classified into (1) histomorphology, (2) biomechanics and, (3) macroscopic morphology. Animals with vaginal implants demonstrated significantly increased M1 and M2 macrophages, MMP‐2, neovascularization, TNF‐α, and stiffness, and lower vaginal contractility compared to control animals.

Conclusion

The host response significantly differs in animals after vaginal mesh implantation compared to control animals, both pro‐ and anti‐inflammatory. However, we observed a paucity in the uniformity of reported outcomes. For future animal studies, we propose the development of a core outcome set, which ideally predicts the host response in women.

In-vitro Characterization of a Hernia Mesh Featuring a Nanostructured Coating

Abdominal hernia repair is a frequently performed surgical procedure worldwide. Currently, the use of polypropylene (PP) surgical meshes for the repair of abdominal hernias constitutes the primary surgical approach, being widely accepted as superior to primary suture repair. Surgical meshes act as a reinforcement for the weakened or damaged tissues and support tissue restoration. However, implanted meshes could suffer from poor integration with the surrounding tissues. In this context, the present study describes the preliminary evaluation of a PCL-Gel-based nanofibrous coating as an element to develop a multicomponent hernia mesh device (meshPCL-Gel) that could overcome this limitation thanks to the presence of a nanostructured biomimetic substrate for enhanced cell attachment and new tissue formation. Through the electrospinning technique, a commercial PP hernia mesh was coated with a nanofibrous membrane from a polycaprolactone (PCL) and gelatin (Gel) blend (PCL-Gel). Resulting PCL-Gel nanofibers were homogeneous and defect-free, with an average diameter of 0.15 ± 0.04 μm. The presence of Gel decreased PCL hydrophobicity, so that membranes average water contact angle dropped from 138.9 ± 1.1° (PCL) to 99.9 ± 21.6°, while it slightly influenced mechanical properties, which remained comparable to those of PCL (E = 15.7 ± 2.7 MPa, σ R = 7.7 ± 0.6 ε R = 118.8 ± 13.2%). Hydrolytic and enzymatic degradation was conducted on PCL-Gel up to 28 days, with maximum weight losses around 20 and 40%, respectively. The meshPCL-Gel device was obtained with few simple steps, with no influences on the original mechanical properties of the bare mesh, and good stability under physiological conditions. The biocompatibility of meshPCL-Gel was assessed by culturing BJ human fibroblasts on the device, up to 7 days. After 24 h, cells adhered to the nanofibrous substrate, and after 72 h their metabolic activity was about 70% with respect to control cells. The absence of detectable lactate dehydrogenase in the culture medium indicated that no necrosis induction occurred. Hence, the developed nanostructured coating provided the meshPCL-Gel device with chemical and topographical cues similar to the native extracellular matrix ones, that could be exploited for enhancing the biological response and, consequently, mesh integration, in abdominal wall hernia repair.

Functionalized multi-walled carbon nanotubes and hydroxyapatite nanorods reinforced with polypropylene for biomedical application

Modified multi-walled carbon nanotubes (f-MWCNTs) and hydroxyapatite nanorods (n-HA) were reinforced into polypropylene (PP) with the support of a melt compounding approach. Varying composition of f-MWCNTs (0.1–0.3 wt.%) and nHA (15–20 wt.%) were reinforced into PP, to obtain biocomposites of different compositions. The morphology, thermal and mechanical characteristics of PP/n-HA/f-MWCNTs were observed. Tensile studies reflected that the addition of f-MWCNTs is advantageous in improving the tensile strength of PP/n-HA nanocomposites but decreases its Young’s modulus significantly. Based on the thermal study, the f-MWCNTs and n-HA were known to be adequate to enhance PP’s thermal and dimensional stability. Furthermore, MTT studies proved that PP/n-HA/f-MWCNTs are biocompatible. Consequently, f-MWCNTs and n-HA reinforced into PP may be a promising nanocomposite in orthopedics industry applications such as the human subchondral bone i.e. patella and cartilage and fabricating certain light-loaded implants.

In Vitro Bacterial Adhesion and Biofilm Formation on Fully Absorbable Poly-4-hydroxybutyrate and Nonabsorbable Polypropylene Pelvic Floor Implants

Knitted polypropylene (PP) implants for the correction of pelvic organ prolapse have been associated with complications such as vaginal exposure, infection, and pain. Since certain complications may be linked to bacterial contamination and persistent inflammation, there is a rationale to develop a biocompatible implant that is less prone to bacterial adhesion and biofilm formation. Delayed absorbable materials could meet these requirements and poly-4-hydroxybutyrate (P4HB) might be such a new material for future pelvic floor implants. We studied in vitro bacterial adhesion and biofilm formation on P4HB in comparison to PP. We investigated the influence of both polymers using flat films and compared P4HB and PP implants with different knitting designs. P4HB flat films were demonstrated to be hydrophilic with significantly less Staphylococcus aureus and Escherichia coli cultured from P4HB films than from hydrophobic PP films after 24 h of incubation. On the implants, a higher number of E. coli were cultured after 1 h of incubation from the knitted P4HB implant with the highest density and smallest pore size, compared to other P4HB and PP implants. No differences were observed between the implants for E. coli at later time points or for S. aureus incubation. These results show that in flat films, the polymer influences biofilm formation, demonstrated by a reduced biofilm formation on P4HB compared with PP flat films. In addition, the knitting design may affect bacterial adhesion. Despite certain design and material characteristics that give the knitted P4HB implants a higher surface area, this did not result in more bacterial adhesion and biofilm formation overall. Collectively, these results warrant further (pre)clinical investigations of P4HB pelvic floor implants.

Smart Implantable Artificial Bladder: An Integrated Design for Organ Replacement

Substituting the natural bladder with an artificial solution, after cancer and other pathologies, is an ambitious challenge in biomedical engineering. In this work we propose a fully implantable smart artificial bladder system (ABS) that collects urinary fluids and provides the subject with real-time feedback on the implant status. To achieve long term duration, the ABS was designed to be unstretchable in order to be treated with urine resistant coatings and included built-in passive check valves preventing reflux to kidneys. To estimate the amount of fluid collected, the ABS was provided with four electromagnetic distance sensing units and a control unit. An algorithm implemented on an embedded controller enabled the reconstruction of the bladder volume through sensors readings. A wireless data transfer system allows for providing a real-time feedback to the subject. Bench tests validated volume reconstruction accuracy and ex-vivo experiments verified the implantability of the proposed device on a human cadaver, proving the reliability of a Bluetooth data transmission system and paving the way towards an in-body/out-body communication. The proposed solution has the potential to overcome the limitations of currently available replacement strategies towards a new generation of implantable devices for lost organ functions replacement.

Immunochemical analysis on polypropylene mesh: does mesh size make a difference?

INTRODUCTION AND HYPOTHESIS

The aim of the study is to demonstrate the impact of the size of implanted mesh in relation to its immunohistochemical reaction implanted into animal models.

METHODS

An experimental study utilizing 54 female Sprague Dawley (SD) rats was divided into five groups: control, sham, and study groups (mesh-small [M-S], mesh-medium [M-M], mesh-large [M-L]). The M-S group used a mesh size of 0.2 × 0.2 cm, the M-M group a mesh size of 0.5 × 0.5 cm, and the M-L a mesh size of 0.7 × 1.0 cm. The sham group underwent vaginal dissection with no mesh implantation. The rats were sacrificed using isoflurane overdose on days 7 and 30. The mesh with the surrounding vaginal and bladder wall tissues were removed and processed for histochemical and western blot analysis.

RESULTS

There is a significant increase in IL-1 and TNF-α immunoreactivity in the M-M and M-L groups on day 7 when compared with the sham group with p values of 0.001 and < 0.001 respectively. M-L showed significantly higher immunoreactivity to TNF-α persisting until day 30. All study groups presented a significantly higher immunoreactivity to MMP-2 and NGF on day 7. However, reactivity to NGF does not persist to day 30 in all groups. Immunoreactivity to CD 31 on days 7 and 30 appears significantly greater in the M-M and M-L groups, with the reaction in the M-L group continuing until day 30.

CONCLUSION

Mesh size is directly proportional to the inflammatory reaction in the host tissue. The prolonged inflammatory process leads to delayed tissue remodeling and angiogenesis, which could delay mesh-tissue integration.

Stress Urinary Incontinence and Pelvic Organ Prolapse: Biologic Graft Materials Revisited

Symptomatic stress urinary incontinence (SUI) and pelvic organ prolapse (POP) refractory to conservative management with pelvic floor muscle training or vaginal pessaries may warrant surgical intervention with different forms of biologic or synthetic material. However, in recent years, several global regulatory agencies have issued health warnings and recalled several mesh products due to an increase in complications such as mesh erosion, infection, chronic pain, and perioperative bleeding. At present, current surgical treatment strategies for SUI and POP are aimed at developing biological graft materials with similar mechanical properties to established synthetic meshes, but with improved tissue integration and minimal host response. This narrative review aims to highlight recent studies related to the development of biomimetic and biologic graft materials as alternatives to traditional synthetic materials for SUI/POP repair in female patients. We also investigate complications and technical limitations associated with synthetic mesh and biological biomaterials in conventional SUI and POP surgery. Our findings demonstrate that newly developed biologic grafts have a lower incidence of adverse events compared to synthetic biomaterials. However there remains a significant disparity between success in preclinical trials and long-term clinical translation. Further characterization on the optimal structural, integrative, and mechanical properties of biological grafts is required before they can be reliably introduced into clinical practice for SUI and POP surgery. Impact statement Our review article aims to outline the clinical history of developments and controversies associated with the use of synthetic mesh materials in the surgical treatment of stress urinary incontinence and pelvic organ prolapse, as well as highlighting recent advancements in the area of biological graft materials and their potential importance in an area that remains an enduring issue for patients and clinicians alike. This article aims to provide a concise summary of previous controversies in the field of urinary incontinence, while evaluating the future of potential biomaterials in this field.

The importance of developing relevant animal models to assess existing and new materials

PURPOSE OF REVIEW

We summarize the recent literature on the use of different animal models for testing existing and new materials for treatment of pelvic organ prolapse.

RECENT FINDINGS

A wide spectrum of animal models is being used in urogynecology, both for the study of physiologic and pathophysiologic processes, training in surgical procedures, yet mainly to study the host response to implant materials. The quality of studies is variable, and procedures, read-outs, and reporting are not standardized. This makes comparison very difficult. The research community is experimenting with different knitting patterns, novel polymers, bioactivation, as well as resorbable rather than durable implants. Outcomes of the experiments are dependent on the location of implantation. Lighter polypropylene constructs seem to induce a less vigorous host response than elder heavier products. Modification of the surface yields contradictory findings. Resorbable acellular collagen matrices may be reintroduced as prophylactically inserted support structures.

SUMMARY

Although animal experimentation with novel candidate implants is advocated, there is a lack of standardization in reporting. The concept of resorbable construct is being revived, as durable materials have caused clinical graft-related complications. Large animal experiments seem to provide interesting and more comprehensive information, yet their use may be contested.

Repair of Orbital Post-Traumatic Wall Defects by Custom-Made TiNi Mesh Endografts

Repairs of orbital post-traumatic and extensive malignant defects remain a major surgical challenge, in view of follow-up outcomes. Incorrect surgical management of injured facial structures results in cosmetic, ophthalmic, and social aftereffects. A custom-made knitted TiNi-based mesh (KTNM) endograft was employed to overcome post-surgical complications and post-resected lesions of the orbital area. Preoperative high-resolution computed tomography (CT) imaging and CAD modelling were used to design the customized KTNM in each case. Twenty-five patients underwent surgery utilizing the suggested technique, from 2014 to 2019. In all documented cases, resolution of the ophthalmic malfunction was noted in the early period. Follow-up observation evidenced no relapsed enophthalmos, hypoglobus, or diplopia as late complications. The findings emanating from our clinical observations allow us to claim that the KTNM indicated a high level of biocompatibility. It is simply modified intraoperatively to attach any desired shape/size for implantation and can also be screw-fixed, providing a good supporting ability. The KTNM precisely renders orbitozygomatic outlines and orbital floor, thus recovering the anatomical structure, and is regarded as an attractive alternative to Ti-based meshes and plates. Additionally, we report one of the studied cases, where good functional and cosmetic outcomes have been achieved.

The challenge of stress incontinence and pelvic organ prolapse: revisiting biologic mesh materials

PURPOSE OF REVIEW

The present article reviews the history of mesh-related complications and regulations in SUI and POP repair settings, clinical outcomes associated with the use of biologic and synthetic mesh materials, and novel approaches using modified mesh materials.

RECENT FINDINGS

Treatment of pelvic floor disorders, such as stress urinary incontinence (SUI) and pelvic organ prolapse (POP) commonly involves implantation of synthetic surgical mesh materials like polypropylene. Many synthetic mesh materials, however, are associated with a foreign body response upon implantation, which is characterized by fibrotic encapsulation. Complications, including erosion, infections, bleeding, and chronic pain, have led to warnings by regulatory agencies and the recall of several mesh products. To mitigate such complications, biologic mesh materials have been proposed as alternatives for SUI and POP repair.

SUMMARY

Clinical outcomes of surgical repair of POP/SUI are similar between biologic and synthetic meshes, but biologic meshes have a lower incidence of adverse effects. Several strategies for modifying or functionalizing biological and synthetic meshes have shown promising results in preclinical studies.

What can we learn from the vaginal mesh story?

The use of vaginal mesh in prolapse surgery has created enormous controversy and unprecedented media interest; it has become the most emotive topic in urogynecology today. The US Food and Drug Administration 510(k) system allowed the proliferation of mesh products which were rapidly adopted by surgeons internationally. The importance of a firm understanding of the biomechanical properties of tissue and implants, surgical skill, patient selection, communication skills, informed consent, and high-quality research are all important lessons we can learn from the mesh story. These lessons need to be applied to all novel treatments in the field of urogynecology and beyond.

Meshes in a mess: Mesenchymal stem cell-based therapies for soft tissue reinforcement

Surgical meshes are frequently used for the treatment of abdominal hernias, pelvic organ prolapse, and stress urinary incontinence. Though these meshes are designed for tissue reinforcement, many complications have been reported. Both differentiated cell- and mesenchymal stem cell-based therapies have become attractive tools to improve their biocompatibility and tissue integration, minimizing adverse inflammatory reactions. However, current studies are highly heterogeneous, making it difficult to establish comparisons between cell types or cell coating methodologies. Moreover, only a few studies have been performed in clinically relevant animal models, leading to contradictory results. Finally, a thorough understanding of the biological mechanisms of mesenchymal stem cells in the context of foreign body reaction is lacking. This review aims to summarize in vitro and in vivo studies involving the use of differentiated and mesenchymal stem cells in combination with surgical meshes. According to preclinical and clinical studies and considering the therapeutic potential of mesenchymal stem cells, it is expected that these cells will become valuable tools in the treatment of pathologies requiring tissue reinforcement. STATEMENT OF SIGNIFICANCE: The implantation of surgical meshes is the standard procedure to reinforce tissue defects such as hernias. However, an adverse inflammatory response secondary to this implantation is frequently observed, leading to a strong discomfort and chronic pain in the patients. In many cases, an additional surgical intervention is needed to remove the mesh. Both differentiated cell- and stem cell-based therapies have become attractive tools to improve biocompatibility and tissue integration, minimizing adverse inflammatory reactions. However, current studies are incredibly heterogeneous and it is difficult to establish a comparison between cell types or cell coating methodologies. This review aims to summarize in vitro and in vivo studies where differentiated and stem cells have been combined with surgical meshes.

Metal-Organic-Framework-Based Enzymatic Microfluidic Biosensor via Surface Patterning and Biomineralization

Recently, the biomineralization of enzyme in metal-organic-framework (enzyme-MOF) composite have shown a great potential to increase enzymes stability without compromising their activity; hence, it is desirable for its applications in biosensing devices. Nonetheless, most of the enzyme-MOF research has been focusing on enzyme encapsulation in particle form, which limits its synthesis flexibility for practical applications because of its requirement for postsynthesis immobilization onto solid support. Therefore, to develop a diagnostic device out of the biomineralized enzyme, surface patterning and integration of microfluidic system offers many advantages. In this work, mussel-inspired polydopamine/polyethyleneimine (PDA/PEI) coating is employed to pattern enzyme-MOF in microfluidic channels and exploit the wettability gradient for "pumpless transportation" effect. As a proof of concept, we combine a cascade reaction of glucose oxidase (GOx) and horseradish peroxidase (HRP) enzymes to detect glucose into a patterned zeolitic imidazole framework-8 (ZIF-8) thin film on a flexible polymeric substrate. The results show that the ZIF-8/GOx&HRP in situ composites on PDA/PEI patterns have good acid and thermal stability compared with samples without ZIF-8. ZIF-8/GOx&HRP in situ shows high selectivity toward glucose, linear sensitivity of 0.00303 Abs/μM, and the limit of detection of 8 μM glucose concentration. An unexpected benefit of this approach is the ability of the ZIF-8 thin-film structure to provide a diffusion limiting effect for substrate influx, thus, producing high range of linear response range (8 μM to 5 mM of glucose). This work provides insights into the spatial location of the enzymes in MOF thin films and the potential of such patterning techniques for MOF-based biosensors using other types of biological elements such as antibodies and aptamers.

Safety and efficacy of non-absorbable mesh in contemporary gynaecological surgery

Mesh-augmented pelvic floor surgery evolved to address the limitations of native tissue repair in reconstructive surgery. The development of the synthetic mid-urethral tape signalled a revolution in the treatment of stress urinary incontinence, whilst the use of mesh in abdominal apical prolapse repair may confer benefits over native tissue alternatives. However, these procedures can be associated with mesh-specific complications, underlining the need for shared decision-making between physicians and patients prior to mesh surgery.

Transvaginal non-absorbable mesh implants for pelvic organ prolapse are associated with a high risk of serious adverse events, leading to withdrawal or restricted use in many countries. Increased scrutiny has led to growing concerns about complications associated with all types of mesh-augmented reconstructive surgery, attracting widespread media attention.

National and international reports have been commissioned examining the safety and efficacy of mesh surgery in gynaecology. They have all highlighted systemic failures in the development, regulation and clinical adoption of medical devices. The widespread application of novel devices prior to the availability of reliable safety and efficacy data, and delayed recognition of adverse events, is of serious concern. Notwithstanding, the available data continue to support a role for mesh augmentation. This review outlines the evolution of gynaecological mesh, the safety and efficacy of pelvic floor surgery using non-absorbable mesh materials, and an overview of specific complications.

Modified laparoscopic pectopexy: short-term follow-up and its effects on sexual function and quality of life

INTRODUCTION AND HYPOTHESIS

This study examined the early outcomes of laparoscopic (LS) pectopexy and evaluated its effects on female sexual function and quality of life (QoL).

METHODS

Twenty-two patients with apical prolapse who underwent LS pectopexy were included. Outcomes of the procedure were noted; the Female Sexual Function (FSFI) and Prolapse Quality of Life (P-QOL) questionnaires were completed preoperatively and 6 months postoperatively.

RESULTS

There was no evidence of recurrent prolapse or constipation; the percentages of exacerbation of cystocele, rectocele, de novo stress urinary incontinence (SUI), and de novo urgency (UUI) were 4.5%, 9.0%, 4.5%, and 4.5%, respectively (mean follow-up 10.41 months). FSFI and P-QOL scores improved significantly (p < 0.05) postoperatively.

CONCLUSIONS

LS pectopexy shows promising results for pelvic organ prolapse (POP) surgery with comparable outcomes. It also improved the FSFI and P-QOL scores in POP patients.

Long-term outcome of vaginal mesh or native tissue in recurrent prolapse: a randomized controlled trial

INTRODUCTION AND HYPOTHESIS

Our aim was to evaluate clinically relevant long-term outcomes of transvaginal mesh or native tissue repair in women with recurrent pelvic organ prolapse (POP).

METHODS

We performed a 7-year follow-up of a randomized controlled trial on trocar-guided mesh placement or native tissue repair in women with recurrent POP. Primary outcome was composite success, defined as absence of POP beyond the hymen, absence of bulge symptoms, and absence of retreatment for POP. Secondary outcomes were adverse events, pain, and dyspareunia. Multiple imputation was used for missing data of composite success and pain; estimates are presented with 95% confidence intervals (CI).

RESULTS

Between August 2006 and July 2008, 194 women were randomized; 190 underwent surgery. At 7 years, 142 (75%) were available for analysis, of whom, the primary outcome could be calculated in 127. Composite success was 53% (95% CI 41, 66) for mesh and 54% (95% CI 42, 65) for native tissue. Repeat surgery for POP was 25% for mesh and 16% for native tissue (difference 9%; 95% CI -5, 23) and occurred in untreated compartments in the mesh group and treated compartments in the native tissue group. Mesh exposure rate was 42%; pain with mesh 39% and native tissue 50% (difference - 11%, 95% CI -27, 6); dyspareunia with mesh 20% and native tissue 17% (difference 3%, 95% CI -9, 17).

CONCLUSIONS

Seven-year composite success rates appeared similar for mesh and native tissue. Mesh did not reduce long-term repeat surgery rates due to de novo POP in nonmesh-treated vaginal compartments. Mesh exposure rates were high, though significant differences in pain and dyspareunia were not detected.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov , NCT00372190.

Structural differences and architectural features of two different polypropylene slings (TVT-O and I-STOP) have no impact on biocompatibility and tissue reactions

Introduction

To evaluate the impact of design features of the synthetic mid-urethral slings on tissue integrity and inflammatory responses.

Material and methods

In total 30 female Sprague-Dawley rats were implanted with type I monofilamentous, macroporous polypropylene meshes: Gynecare TVT-Obturator tape^® (Ethicon Inc., Johnson & Johnson, Somerville, NJ, USA) and I-STOP^® (CL Medical Inc., Lyon, France). All animal groups were sacrificed at set time intervals – 6 weeks, 3 months, 6 months, 9 months and 12 months – and the abdominal wall was harvested with mesh strips for histological evaluation.

Results

All mesh strips appeared to be well incorporated into the abdominal wall, and no signs of shrinkage was noticed. All specimens showed a thin/delicate, loose, fibrous interface between the synthetic graft plate and abdominal wall, along with mild inflammatory reactions from 6 weeks to 12 months.

Conclusions

Both mesh brands induced comparable, minimal foreign body reactions and integrated well into the host tissues despite differences in architectural features. TVT-O^® and I-STOP^® evoked similar low-grade inflammatory responses up to 12 months in this animal model.

Structural differences and architectural features of polypropylene slings used in this study have had no impact on tissue integrity and inflammatory responses.