Comparison of long-term biocompability of PVDF and PP meshes

Choice of Polymer, but Not Mesh Structure Variation, Reduces the Risk of Bacterial Infection with Staphylococcus aureus In Vivo

BACKGROUND

Synthetic mesh material is of great importance for surgical incisional hernia repair. The physical and biochemical characteristics of the mesh influence mechanical stability and the foreign body tissue reaction. The influence on bacterial infections, however, remains ill-defined. The aim of the present study was to evaluate the influence of a modified mesh structure with variation in filament linking on the occurrence of bacterial infection that is indicated by the occurrence of CD68⁺, CD4⁺, and CD8⁺ cells in two different materials.

METHODS

A total of 56 male Sprague Dawley rats received a surgical mesh implant in a subcutaneous abdominal position. The mesh of two different polymers (polypropylene (PP) and polyvinylidenfluoride (PVDF)) and two different structures (standard structure and bold structure with higher filament linking) were compared. During the implantation, the meshes were infected with Staphylococcus (S.) aureus. After 7 and 21 days, meshes were explanted, and the early and late tissue responses to infection were histologically evaluated.

RESULTS

Overall, the inflammatory tissue response was higher at 7 days when compared to 21 days. At 7 days, PP meshes of the standard structure (PP-S) showed the strongest inflammatory tissue response in comparison to all the other groups. At 21 days, no statistically significant difference between different meshes was detected. CD8⁺ cytotoxic T cells showed a significant difference at 21 days but not at 7 days. PP meshes of both structures showed a higher infiltration of CD8⁺ T cells than PVDF meshes. CD4⁺ T helper cells differed at 7 days but not at 21 days, and PVDF meshes in a bold structure showed the highest CD4⁺ T cell count. The number of CD68⁺ macrophages was also significantly higher in PP meshes in a standard structure when compared to PVDF meshes at 21 days.

CONCLUSION

The inflammatory tissue response to S. aureus infection appears to be highest during the early period after mesh implantation. PP meshes showed a higher inflammatory response than PVDF meshes. The mesh material appears to be more important for the risk of infection than the variation in filament linking.

Surgical results in POP/UI surgery after using PVDF compared to other materials. A systematic review and meta-analysis

OBJECTIVES

Synthetic materials have been used for the surgical treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP). During the last 25 years, these materials were composed mostly of polypropylene (PP), whereas recently the use of polyvinylidene difluoride (PVDF) is of increasing interest due to its characteristics. This study aimed to compare the results after SUI/POP surgery using PVDF versus PP materials by synthesizing the data of relevant existing literature.

STUDY DESIGN

This systematic review and meta-analysis included clinical trials, case-control studies, or cohort studies written in the English language. The search strategy included the electronic databases MEDLINE, EMBASE, and Cochrane, and grey literature (congresses IUGA, EUGA, AUGS, FIGO). All studies have to provide numeric data or odds ratios (OR) of developing a specific outcome in surgeries with PVDF compared with outcomes of other used materials. No restrictions of race or ethnicity were applied, nor chronological restrictions. Exclusion criteria were studies that included patients with cognitive impairment, dementia, stroke, or central nervous system trauma. All studies were screened by two reviewers, initially by title and abstract, and afterward by full text. Disagreements were resolved through mutual consent. All studies were assessed for their quality and bias risk. Data were extracted using a data extraction form formulated in a Microsoft Excel spreadsheet. Our results were divided into studies dealing only with SUI patients, studies dealing only with POP patients, and cumulative analysis of variables expressed in both SUI and POP surgery. The primary outcomes were the rates of post-operative recurrence, mesh erosion, and postoperative pain after surgery with PVDF compared to PP. The secondary outcomes were post-operative sexual dissatisfaction, overall satisfaction rates, hematoma, urinary tract infection, de novo urge incontinence, and reoperation rate.

RESULTS

No differences in the post-operative rates of SUI/POP recurrence, mesh erosion, and pain were found after surgery with PVDF vs surgery with PP. Patients after SUI surgery with PVDF tapes had statistically significant lower rates of de-novo urgency compared to the PP group [OR = 0.38 (0.18, 0.88), p = 0.01]; patients after POP surgery with PVDF materials had statistically significant lower rates of de-novo sexual dysfunction compared to the PP group [OR = 0.12 (0.03, 0.46), p = 0.002].

CONCLUSIONS

This study provided evidence that the use of PVDF in SUI/POP surgeries could be a valid alternative to PP. However our results are limited by uncertainty due to the overall low quality of the existent data. Further research and validation would contribute to better surgical techniques.

AbsorbaTack™ vs. ProTack™ vs. sutures: a biomechanical analysis of cervical fixation methods for laparoscopic apical fixations in the porcine model

PURPOSE

Treatment of pelvic organ prolapse (POP) often requires the use of synthetic mesh. In case of a novel and standardized bilateral apical fixation, both uterosacral ligaments are replaced by polyvinylidene-fluoride (PVDF) tapes. One of the main problems remains the fixation method, which should be stable, but also simple and quick to use. The current study evaluated biomechanical differences between the cervical tape fixation with sutures (group 1), non-absorbable tacks (group 2) and absorbable tacks (group 3) in an in vitro porcine model.

METHODS

A total of 28 trials, conducted in three groups, were performed on porcine, fresh cadaver uteri. All trials were performed until mesh, tissue or fixation device failure occurred. Primary endpoints were the biomechanical properties maximum load (N), displacement at failure (mm) and stiffness (N/mm). The failure mode was a secondary endpoint.

RESULTS

There was a significant difference between all three groups concerning the maximum load. Group 1 (sutures) supported a maximum load of 64 ± 15 N, group 2 (non-absorbable tacks) yielded 41 ± 10 N and group 3 (absorbable tacks) achieved 15 ± 8 N. The most common failure mode was a mesh failure for group 1 and 2 and a fixation device failure for group 3.

CONCLUSION

The PVDF-tape fixation with sutures supports 1.5 times the load that is supported by non-absorbable tacks and 4.2 times the load that is supported by absorbable tacks. Nevertheless, there was also a stable fixation through tacks. Sutures are the significantly stronger and cheaper fixation device but may prolong the surgical time in contrast to the use of tacks.

Future prospects and recent developments of polyvinylidene fluoride (PVDF) piezoelectric polymer; fabrication methods, structure, and electro-mechanical properties

Polyvinylidene fluoride (PVDF) is a favorite polymer with excellent piezoelectric properties due to its mechanical and thermal stability. This article provides an overview of recent developments in the modification of PVDF fibrous structures and prospects for its application with a major focus on energy harvesting devices, sensors and actuator materials, and other types of biomedical engineering and devices. Many sources of energy harvesting are available in the environment, including waste-heated mechanical, wind, and solar energy. While each of these sources can be impactively used to power remote sensors, the structural and biological communities have emphasized scavenging mechanical energy by functional materials, which exhibit piezoelectricity. Piezoelectric materials have received a lot of attention in past decades. Piezoelectric nanogenerators can effectively convert mechanical energy into electrical energy suitable for low-powered electronic devices. Among piezoelectric materials, PVDF and its copolymers have been extensively studied in a diverse range of applications dealing with recent improvements in flexibility, long-term stability, ease of processing, biocompatibility, and piezoelectric generators based on PVDF polymers. This article reviews recent developments in the field of piezoelectricity in PVDF structure, fabrication, and applications, and presents the current state of power harvesting to create completely self-powered devices. In particular, we focus on original approaches and engineering tools to design construction parameters and fabrication techniques in electro-mechanical applications of PVDF.

Cyto- and bio-compatibility assessment of plasma-treated polyvinylidene fluoride scaffolds for cardiac tissue engineering

As part of applications dealing with cardiovascular tissue engineering, drop-cast polyvinylidene fluoride (PVDF) scaffolds have been treated by cold plasma to enhance their adherence to cardiac cells. The scaffolds were treated in a dielectric barrier device where cold plasma was generated in a gaseous environment combining a carrier gas (helium or argon) with/without a reactive gas (molecular nitrogen). We show that an Ar-N₂ plasma treatment of 10 min results in significant hydrophilization of the scaffolds, with contact angles as low as 52.4° instead of 132.2° for native PVDF scaffolds. Correlation between optical emission spectroscopy and X-ray photoelectron spectroscopy shows that OH radicals from the plasma phase can functionalize the surface scaffolds, resulting in improved wettability. For all plasma-treated PVDF scaffolds, the adhesion and maturation of primary cardiomyocytes is increased, showing a well-organized sarcomeric structure (α-actinin immunostaining). The efficacy of plasma treatment was also supported by real-time PCR analysis to demonstrate an increased expression of the genes related to adhesion and cardiomyocyte function. Finally, the biocompatibility of the PVDF scaffolds was studied in a cardiac environment, after implantation of acellular scaffolds on the surface of the heart of healthy mice. Seven and 28 days after implantation, no exuberant fibrosis and no multinucleated giant cells were visible in the grafted area, hence demonstrating the absence of foreign body reaction and the biocompatibility of these scaffolds.

The early outcomes of complex abdominal wall reconstruction with polyvinylidene (PVDF) mesh in the setting of active infection: a prospective series

PURPOSE

The use of synthetic mesh to repair infected abdominal wall defects remains controversial. Polyvinylidene fluoride (PVDF) mesh was introduced in 2002 as an alternative to polypropylene, with the advantages of improved biostability, lowered bending stiffness, and minimum tissue response. This study aimed to evaluate the short-term outcomes of using PVDF mesh to treat infected abdominal wall defects in the elective setting.

METHODS

This prospective clinical trial started in 2016 and was designed to evaluate the short- and mid-term outcomes of 38 patients submitted to abdominal wall reconstruction in the setting of active mesh infection and/or enteric fistulas (AI) when compared to a group of 38 patients submitted to clean ventral hernia repairs (CC). Patients were submitted to single-staged repairs, using onlay PVDF mesh (DynaMesh®-CICAT) reinforcement to treat their defects.

RESULTS

Groups had comparable demographic characteristics. The AI group had more previous abdominal operations and required a longer operative and anesthesia time. At 30 days, surgical site occurrences were observed in 16 (42.1%) AI vs. 17 (44.7%) CC, p = 0.817; surgical site infection occurred in 4 (10.5%) AI vs. 6 (15.8%) CC, p = 0.497; and a higher number of procedural interventions were required in the CC group, 15.8 AI vs. 28.9% CC, p = 0.169. Both groups did not have chronic infections at 1 year of follow-up, and one hernia recurrence was observed in the AI group.

CONCLUSIONS

The use of PVDF mesh in the infected setting presented favorable results with a low incidence of wound infection.

Tacks vs. sutures: a biomechanical analysis of sacral bony fixation methods for laparoscopic apical fixations in the porcine model

Purpose

There is a novel surgical procedure, called cervicosacropexy (CESA) and vaginosacropexy (VASA) to treat pelvic organ prolapse and a concomitant urgency and mixed urinary incontinence. As there is little experience with the tapes so far and literature is scanty, the aim of this study was to investigate biomechanical properties for the fixation of the PVDF-tapes with three different fixation methods in context of apical fixations.

Methods

Evaluation was performed on porcine, fresh cadaver sacral spines. A total of 40 trials, divided into 4 subgroups, was performed on the anterior longitudinal ligament. Recorded biomechanical properties were displacement at failure, maximum load and stiffness in terms of the primary endpoints. The failure mode was a secondary endpoint. Group 4 was a reference group to compare single sutures on porcine tissue with those on human tissue. Biomechanical parameters for single sutures on the human anterior longitudinal ligament were evaluated in a previous work by Hachenberg et al.

Results

The maximum load for group 1 (two single sutures) was 65 ± 12 N, for group 2 (three titanium tacks arranged in a row) it was 25 ± 10 N and for group 3 (three titanium tacks arranged in a triangle) it was 38 ± 12 N. There was a significant difference between all three groups. The most common failure mode was a “mesh failure” in 9/10 trials for groups 1–3.

Conclusion

The PVDF-tape fixation with two single sutures endures 2.6 times more load than titanium tacks arranged in a row and 1.7 times more load than titanium tacks arranged in a triangle. The presacral fixation with titanium tacks reduced surgical time compared to the fixation with sutures, nevertheless sutures represent the significantly stronger and cheaper fixation method.

A novel characterisation approach to reveal the mechano-chemical effects of oxidation and dynamic distension on polypropylene surgical mesh

Polypropylene (PP) surgical mesh, used successfully for the surgical repair of abdominal hernias, is associated with serious clinical complications when used in the pelvic floor for repair of stress urinary incontinence or support of pelvic organ prolapse. While manufacturers claim that the material is inert and non-degradable, there is a growing body of evidence that asserts PP fibres are subject to oxidative damage and indeed explanted material from patients suffering with clinical complications has shown some evidence of fibre cracking and oxidation. It has been proposed that a pathological cellular response to the surgical mesh contributes to the medical complications; however, the mechanisms that trigger the specific host response against the material are not well understood. Specifically, this study was constructed to investigate the mechano-chemical effects of oxidation and dynamic distension on polypropylene surgical mesh. To do this we used a novel advanced spectroscopical characterisation technique, secondary electron hyperspectral imaging (SEHI), which is based on the collection of secondary electron emission spectra in a scanning electron microscope (SEM) to reveal mechanical-chemical reactions within PP meshes.

Transvaginal repair of anterior vaginal wall prolapse with polyvinylidene fluoride (PVDF) mesh: an alternative for previously restricted materials?

INTRODUCTION AND HYPOTHESIS

To study the mid-term safety and functional outcomes of transvaginal anterior vaginal wall prolapse repair using polyvinylidene fluoride (PVDF) mesh (DynaMesh®-PR4) by the double trans-obturator technique (TOT).

METHODS

Between 2015 and 2020, we prospectively included women with symptomatic high-stage anterior vaginal wall prolapse with or without uterine prolapse or stress urinary incontinence (SUI) in the study. The patients underwent transvaginal repair of the prolapse using PVDF mesh in two medical centers. We followed all patients for at least 12 months. We recorded the characteristics of vaginal and sexual symptoms, urinary incontinence, and prolapse stage pre- and postoperatively using International Consultation on Incontinence Questionnaire-Vaginal Symptoms (ICIQ-VS), International Consultation on Incontinence Questionnaire-Urinary Incontinence-Short Form (ICIQ-UI-SF), and Pelvic Organ Prolapse Quantification (POP-Q) system, respectively.

RESULTS

One hundred eight women were included in the final analysis with a mean follow-up time of 34.5 ± 18.6 months. The anatomical success was achieved in 103 (95.4%) patients. There was a significant improvement in patients' vaginal symptoms, urinary incontinence, and quality of life scores postoperatively (p < 0.0001). Only six patients (5.5%) had mesh extrusion, five of whom were managed successfully. The total rates of complications and de novo urinary symptoms were 21.3% and 7.4%, respectively. Significant pain was reported in 17 cases (15.7%).

CONCLUSION

Our findings show that using PVDF mesh in the double TOT technique for anterior vaginal wall prolapse repair is a safe procedure with high anatomic and functional success rates and acceptable complication rates in mid-term follow-up.

Degradation resistance of PVDF mesh in vivo in comparison to PP mesh

Mesh implant has been applied in hernia repair and urogynecological reconstruction. Polypropylene (PP) is now the most widely used material for non-resorbable mesh implants. A degradation phenomenon of PP mesh, which is apparent on the mesh surface as cracking, flaking and peeling, was discovered in the 1990's. This phenomenon of mesh implant has drawn attention because of mesh-related litigations. Polyvinylidene fluoride (PVDF), due to its high biocompatible performance, has been used since 2003 as an alternative material for non-resorbable mesh implants. Till now, no such degradation phenomenon of PVDF mesh has been reported, although limited study on PVDF mesh is available. In this paper, we researched the degradation of PVDF meshes taking the degradation of PP mesh as a reference. The meshes analysed in this study were received from a previous animal experiment. To expose the surface of explanted meshes, a tissue removing method with protease was used and the result of this cleaning process was tested by X-ray Photoelectron Spectroscopy (XPS). The morphological condition of the mesh surface was compared using Scanning Electron Microscopy (SEM) and the chemical condition concerning degradation was analysed through Fourier Transform Infrared Spectroscopy (FTIR). The surface condition of PVDF mesh after 3-, 6-, 12- and 24-month implantation was illustrated and compared with two types of PP meshes. XPS revealed an absence of nitrogen, confirming the successful removal of tissue residues using protease. SEM results presented no notable morphological surface change of the PVDF mesh and progressive surface cracking processes over time of both types of PP meshes. FTIR spectra of the implanted PVDF meshes had no considerable difference from the spectrum of the pristine mesh, while FTIR spectra of both types of PP meshes had extra chemical functional groups (carbonyl (CO) and hydroxyl (-OH) groups) increasing with implantation time, indicating progressive degradation. This study highlights the morphological and chemical stability of the PVDF mesh and demonstrates that the PVDF mesh is more resistant to degradation in comparison to the other two types of PP meshes.

Development of electrospun core-shell polymeric mat using poly (ethyl-2) cyanoacrylate/polyurethane to attenuate biological adhesion on polymeric mesh implants

Poly (ethyl-2) cyanoacrylate was used to create an adhesion-free biocompatible non-woven material reinforced by polyurethane core via a co-axial electrospinning set-up. The effect of relative humidity (RH) of (18, 30, 40, 60, and 68) % on the electrospinning process was examined, and found that in order to achieve well defined core-shell fiber structure, the optimal RH was 18%. If the RH is >18%, a phenomenon called Taylor cone cyclic destabilization occurs, which results in unfavorable surface and mechanical properties of the mat. The developed composite electrospun mat has the potential to be used in medical devices, such as repairing the viscera layer for intraperitoneal hernia mesh implants, which require the attenuation of biological elements, and adequate mechanical properties.

Laparoscopic latero-abdominal colposuspension: Description of the technique, advantages and preliminary results

INTRODUCTION

There are currently various fixation or suspension techniques for pelvic organ prolapse (POP) surgery. Laparoscopic colposacropexy is considered the gold standard. We present the surgical steps of the laparoscopic latero-abdominal colposuspension (LACS) technique and the preliminary results obtained.

MATERIAL AND METHODS

Patients with anterior and/or apical compartment symptomatic POP undergoing LACS are included. The Baden-Walker scale, the Overactive Bladder Questionnaire-Short Form (OAB-q SF), the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12) and the Patient Global Impression of Improvement (PGI-I) scale were used to assess the degree of prolapse, urinary filling and sexual symptoms and the level of satisfaction before and after surgery, respectively. Conventional laparoscopic material and a polyvinylidene fluoride (PVDF) mesh were used.

RESULTS

Eighteen patients were included with a minimum follow-up time of 6months. The mean surgical time was 70.3±23.8min. Anatomic correction of prolapse was seen in all cases. Only one recurrence was detected. High levels of patient satisfaction were achieved.

CONCLUSION

LACS allowed the anatomical reconstruction of the pelvic floor and proved to be a minimally invasive, fast, effective, safe and reproducible technique. More series are needed to evaluate its role against laparoscopic colposacropexy.

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.

Cross-section modified and highly elastic sutures reduce tissue incision and show comparable biocompatibility: in-vitro and in-vivo evaluation of novel thermoplastic urethane surgical threads

Surgical sutures are indispensable for a vast majority of operative procedures. An ideal suture is characterized by high tissue compliance without cutting into the mended tissue and optimal biocompatibility. Therefore, we assessed these mechanical and biological properties for novel elastic thermoplastic polyurethane (TPU) and cross-sectional modified "snowflake" sutures. Circular and "snowflake"-shaped TPU threads were manufactured and compared to similar surface modified polyvinylidene fluoride (PVDF) sutures. Regular PVDF sutures were used as the control group. Single-axis tensile test with and without gelatinous tissue surrogates were performed to evaluate the suture incision into the specimens. Biocompatibility was evaluated by subcutaneous implantation (n = 18) in rats for 7 and 21 days. Histology and immunohistology was conducted for assessment of the foreign body reaction. Regular and modified TPU threads showed a significant reduction of incision into the tissue surrogates compared to the control. Both TPU sutures and the modified PVDF sutures achieved comparable biocompatibility versus regular PVDF threads. Detailed histology revealed novel tissue integration into the notches of the surface modified sutures, we termed this newly shaped granuloma "intrafilamentous" granuloma. Elastic TPU threads showed a significant reduction of tissue surrogate incision and suture tension loss. Biocompatibility did not significantly differ from standard PVDF. Histology demonstrated tissue ingrowth following the surface modification of the suture referred to as "intrafilamentous" granuloma. Further in vivo studies are required to illuminate the exact potential of the new sutures to optimize intestinal anastomosis.

Laparoscopic sacrocolpopexy comparing polypropylene mesh with polyvinylidene fluoride mesh for pelvic organ prolapse: Technique description and long term outcomes

AIM

Our aim was to evaluate the feasibility and safety of laparoscopic sacrocolpopexy (LSCP) and compare the long-term outcomes and complication rates of polypropelene (PP) and polyvinylidene fluoride (PVDF), following up within a minimum of 12 months.

METHODS

This was a retrospective cohort study using patients who underwent LSCP for POP involving either PP or PVDF mesh between January 2011 and January 2018.

RESULTS

Our study focused on 172 women who underwent LSCP with mesh between January 2011 and January 2018. All procedures were successfully completed laparoscopically, and patients' baseline characteristics were not statistically different in the two groups. Between January 2011 and December 2014, we performed 82 cases of LSC, mainly using PP mesh. Over the last 5 years, since January 2015, we have used PVDF mesh for POP.

CONCLUSIONS

LSCP using PVDF mesh was found to provide excellent anatomical and functional outcomes after a median follow-up duration of 41 months, compared with the PP group, which had a median follow-up duration of 54 months. Mesh infection and erosion rates in the PP group were significantly higher than those in the PVDF group. Additionally, rates of vaginal pain and discomfort were significantly lower in the PVDF group when compared with the PP group.

Use of polyvinylidene fluoride (PVDF) meshes for ventral hernia repair in emergency surgery

PURPOSE

The implantation of non-absorbable meshes is the gold standard technique for ventral hernia (VH) repairs. However, emergency surgeries are often related to contaminated/infected fields, where the implantation of prosthetic materials may not be recommendable. Our aim was to evaluate the results of polyvinylidene fluoride (PVDF) meshes used for contaminated and/or complicated VH repairs in the acute setting.

METHODS

We conducted a retrospective analysis of patients with VH who underwent emergency surgery involving PVDF meshes, in a tertiary hospital (from November 2013 to September 2019). We analyzed postoperative complications and 1-year recurrence rates. We evaluated the relationships between contamination grade, mesh placement, infectious complications, and recurrences.

RESULTS

We gathered data on 123 patients; their mean age was 62.3 years, their mean BMI was 31.1 kg/m², and their mean CeDAR index was 51.6. 96.4% of patients had a grade 2-3 ventral hernia according to the Rosen index. The mean defect width was 8 cm (IQR 2-18). 93 cases (75.6%) were described as contaminated or dirty surgeries. A PVDF mesh was placed using an IPOM technique in 56.3% of cases, and via interposition location in 39.9%. The one-month recurrence rate was 5.7% and recurrence after one year was 19.1%. The overall mortality rate was 27.6%. Risk of recurrence was related to patients with a Rosen score over 2 (p < 0.001), as well as with postoperative SSI (p = 0.045). Higher recurrence rates were not related to PVDF mesh placement.

CONCLUSION

The use of PVDF meshes for emergency VH repairs in contaminated surgeries seems safe and useful, with reasonable recurrence rates, and acceptable infectious complication rates, similar to those published in the literature.

Effectiveness of Prophylactic Intraperitoneal Mesh Implantation for Prevention of Incisional Hernia in Patients Undergoing Open Abdominal Surgery: A Randomized Clinical Trial

Importance

Incisional hernia is a frequent complication after open abdominal surgery. Prophylactic mesh implantation in the onlay or sublay position requires dissection of the abdominal wall, potentially leading to wound-associated complications.

Objective

To compare the incidence of incisional hernia among patients after prophylactic intraperitoneal mesh implantation with that among patients after standard abdominal closure.

Design, Setting, and Participants

An open-label randomized clinical trial was performed in 169 patients undergoing elective open abdominal surgery from January 1, 2011, to February 29, 2014. Follow-up examinations were performed 1 year and 3 years after surgery. The study was conducted at Bern University Hospital, Bern, Switzerland, a referral center that offers the whole spectrum of abdominal surgical interventions. Patients with 2 or more of the following risk factors were included: overweight or obesity, diagnosis of neoplastic disease, male sex, or history of previous laparotomy. Patients were randomly assigned to prophylactic intraperitoneal mesh implantation or standard abdominal closure. Data were analyzed in August 2017.

Interventions

Intraperitoneal implantation of a polypropylene-polyvinylidene fluoride mesh with circumferential fixation.

Main Outcomes and Measures

The primary end point was the incidence of incisional hernia 3 years after surgery. Secondary end points included mesh-related complications.

Results

After the exclusion of 19 patients, 150 patients (81 in the control group and 69 in the mesh group; mean [SD] age, 64.2 [11.1] years; 102 [68.0%] male) were studied. The cumulative incidence of incisional hernia was significantly lower in the mesh group compared with the control group (5 of 69 [7.2%] vs 15 of 81 [18.5%], log-rank test P = .03). Abdominal pain was observed in significantly more patients in the mesh group compared with the control group at 6 weeks (34 of 52 [65%] vs 26 of 59 [44%], P = .04) but not at 12 and 36 months postoperatively. No difference in surgical site infections was observed, but time to complete wound healing of surgical site infection was significantly longer in patients with mesh implantation (median [interquartile range], 8 [6-24] weeks compared with 5 [1-9] weeks; P = .03). Trunk extension was significantly decreased after mesh implantation compared with the control group (mean [SD], 1.73 [0.97] cm vs 2.40 [1.23] cm, P = .009).

Conclusions and Relevance

In patients at elevated risk for incisional hernia, prophylactic intraperitoneal mesh implantation reduces the incidence of hernia formation but with increased early postoperative pain and prolonged wound healing of surgical site infection.

Trial Registration

ClinicalTrials.gov Identifier: NCT01203553.

Parameters of 2-Dimensional Perineal Ultrasonography Before and After Male Sling Procedure for Urinary Incontinence After Radical Prostatectomy

OBJECTIVE

To compare ultrasonographic patterns of 2-dimensional perineal ultrasonography in men in the preoperative and postoperative periods after transobturator sling deployment for the treatment of urinary incontinence after radical prostatectomy. Radiotherapy and radical prostatectomy are the primary treatments for localized prostate cancer. Studies comparing anatomic changes in men before and after radical prostatectomy based on perineal ultrasonography are scarce in the literature.

METHODS

Thirty-one patients from 2 centers were selected for examination and surgery. They were allocated into mild and/or moderate and severe incontinence groups who underwent the transobturator sling procedure between August 2014 and August 2018. Perineal ultrasonography was performed in the preoperative period for 21 of these patients and 3-6 months postoperatively after the transobturator sling procedure for 30 patients. Hypermobility of the proximal urethra and voluntary contraction of the pelvic floor were evaluated during the Valsalva maneuver, perineal contraction and at rest.

RESULTS

Clinical improvements of >50% were significantly more frequent in the mild and/or moderate vs severe incontinence group after male sling surgery (P = .035). Patients who demonstrated clinical improvement >50% showed a significantly greater displacement of the posterior portion of the bladder neck during contraction than those with clinical improvement <50% (P = .024).

CONCLUSION

The most important finding of this study was the significant difference in the posterior displacement of the bladder neck during contraction in patients who showed an improvement >50% compared with those with an improvement <50%. These data support the use of perineal ultrasonography in evaluating and selecting patients for the male sling procedure.

Laparoscopic Bilateral Cervicosacropexy and Vaginosacropexy: New Surgical Treatment Option in Women with Pelvic Organ Prolapse and Urinary Incontinence

Objective: Sacrocolpopexy (SCP) is the gold standard for apical prolapse treatment. However, the technical performance of each SCP is strongly dependent on the surgeon's own discretion and comparison of clinical outcomes with respect to urinary incontinence (UI) is difficult. We developed a comprehensible laparoscopic surgical technique for the treatment of apical prolapse with UI.

Methods: A total of 120 women with UI underwent laparoscopic bilateral SCP for apical prolapse. Thereby, the uterosacral ligaments (USLs) were bilaterally replaced by polyvinylidene fluoride (PVDF) tapes of identical length and shape, which were fixed at defined anatomical landmarks (cervix/vaginal vault and S1).

Results: The restoration of apical vaginal support was achieved in 116 patients (97%); restoration failed in the first 4 patients owing to the use of fast-absorbable sutures. Seventy-eight patients (65%) with mixed and urgency UI symptoms before surgery achieved continence. The mean hospitalization was 3 days; no major complications were observed intraoperatively.

Conclusion: The advantage of laparoscopic cervicosacropexy (laCESA) and laparoscopic vaginosacropexy (laVASA) lies in the comprehensible surgical technique (clearly defined technique) and the minimal amount of material used (no polypropylenes). The possibility of a short operating time and short hospitalization depicts this laparoscopic bilateral USL replacement as one treatment alternative in patients with apical prolapse suffering from UI.

Improved biocompatibility of profiled sutures through lower macrophages adhesion

The biocompatibility of a textile implant is determined by various parameters, such as material composition and surface chemistry. However, little is known about the influence of geometry of sutures on biocompatibility. To elucidate this factor we focused on geometry-modification resulting in ultrafine polyethylene terephthalate (UFPET) suture and a snowflake like shaped polyvenylidenfluorid (PVDF) suture. Forty-eight rats were divided into two observation periods. In each rat 3 out of 4 sutures (profiled UFPET, snowflake-like profiled PVDF, reference Prolene and Mersilene suture) were randomly placed into the subcutaneous tissue. Rats were euthanized after 7 and 21 days and samples were explanted. Foreign body granuloma was measured and expression of CD68, TUNEL, Ki-67 and Collagen I/III ratio were determined. The profiled (snowflake) suture showed a significantly smaller FBG in comparison to standard sutures (p < 0.001). Both modified sutures showed a significant lower tissue remodeling by Ki-67 and TUNEL expression (p < 0.03). Furthermore, profiled sutures caused a lower inflammatory reaction expressed in a significant lower amount of CD68 positive macrophages after 21 days (p < 0.001). Modifications of suture geometry alter the foreign body granuloma and the inflammatory reaction. Therefore, profiled sutures might be a promising approach to improve biocompatibility of textile mesh prosthesis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1772-1778, 2019.

International guidelines for groin hernia management

INTRODUCTION

Worldwide, more than 20 million patients undergo groin hernia repair annually. The many different approaches, treatment indications and a significant array of techniques for groin hernia repair warrant guidelines to standardize care, minimize complications, and improve results. The main goal of these guidelines is to improve patient outcomes, specifically to decrease recurrence rates and reduce chronic pain, the most frequent problems following groin hernia repair. They have been endorsed by all five continental hernia societies, the International Endo Hernia Society and the European Association for Endoscopic Surgery.

METHODS

An expert group of international surgeons (the HerniaSurge Group) and one anesthesiologist pain expert was formed. The group consisted of members from all continents with specific experience in hernia-related research. Care was taken to include surgeons who perform different types of repair and had preferably performed research on groin hernia surgery. During the Group's first meeting, evidence-based medicine (EBM) training occurred and 166 key questions (KQ) were formulated. EBM rules were followed in complete literature searches (including a complete search by The Dutch Cochrane database) to January 1, 2015 and to July 1, 2015 for level 1 publications. The articles were scored by teams of two or three according to Oxford, SIGN and Grade methodologies. During five 2-day meetings, results were discussed with the working group members leading to 136 statements and 88 recommendations. Recommendations were graded as "strong" (recommendations) or "weak" (suggestions) and by consensus in some cases upgraded. In the Results and summary section below, the term "should" refers to a recommendation. The AGREE II instrument was used to validate the guidelines. An external review was performed by three international experts. They recommended the guidelines with high scores. The risk factors for inguinal hernia (IH) include: family history, previous contra-lateral hernia, male gender, age, abnormal collagen metabolism, prostatectomy, and low body mass index. Peri-operative risk factors for recurrence include poor surgical techniques, low surgical volumes, surgical inexperience and local anesthesia. These should be considered when treating IH patients. IH diagnosis can be confirmed by physical examination alone in the vast majority of patients with appropriate signs and symptoms. Rarely, ultrasound is necessary. Less commonly still, a dynamic MRI or CT scan or herniography may be needed. The EHS classification system is suggested to stratify IH patients for tailored treatment, research and audit. Symptomatic groin hernias should be treated surgically. Asymptomatic or minimally symptomatic male IH patients may be managed with "watchful waiting" since their risk of hernia-related emergencies is low. The majority of these individuals will eventually require surgery; therefore, surgical risks and the watchful waiting strategy should be discussed with patients. Surgical treatment should be tailored to the surgeon's expertise, patient- and hernia-related characteristics and local/national resources. Furthermore, patient health-related, life style and social factors should all influence the shared decision-making process leading up to hernia management. Mesh repair is recommended as first choice, either by an open procedure or a laparo-endoscopic repair technique. One standard repair technique for all groin hernias does not exist. It is recommended that surgeons/surgical services provide both anterior and posterior approach options. Lichtenstein and laparo-endoscopic repair are best evaluated. Many other techniques need further evaluation. Provided that resources and expertise are available, laparo-endoscopic techniques have faster recovery times, lower chronic pain risk and are cost effective. There is discussion concerning laparo-endoscopic management of potential bilateral hernias (occult hernia issue). After patient consent, during TAPP, the contra-lateral side should be inspected. This is not suggested during unilateral TEP repair. After appropriate discussions with patients concerning results tissue repair (first choice is the Shouldice technique) can be offered. Day surgery is recommended for the majority of groin hernia repair provided aftercare is organized. Surgeons should be aware of the intrinsic characteristics of the meshes they use. Use of so-called low-weight mesh may have slight short-term benefits like reduced postoperative pain and shorter convalescence, but are not associated with better longer-term outcomes like recurrence and chronic pain. Mesh selection on weight alone is not recommended. The incidence of erosion seems higher with plug versus flat mesh. It is suggested not to use plug repair techniques. The use of other implants to replace the standard flat mesh in the Lichtenstein technique is currently not recommended. In almost all cases, mesh fixation in TEP is unnecessary. In both TEP and TAPP it is recommended to fix mesh in M3 hernias (large medial) to reduce recurrence risk. Antibiotic prophylaxis in average-risk patients in low-risk environments is not recommended in open surgery. In laparo-endoscopic repair it is never recommended. Local anesthesia in open repair has many advantages, and its use is recommended provided the surgeon is experienced in this technique. General anesthesia is suggested over regional in patients aged 65 and older as it might be associated with fewer complications like myocardial infarction, pneumonia and thromboembolism. Perioperative field blocks and/or subfascial/subcutaneous infiltrations are recommended in all cases of open repair. Patients are recommended to resume normal activities without restrictions as soon as they feel comfortable. Provided expertise is available, it is suggested that women with groin hernias undergo laparo-endoscopic repair in order to decrease the risk of chronic pain and avoid missing a femoral hernia. Watchful waiting is suggested in pregnant women as groin swelling most often consists of self-limited round ligament varicosities. Timely mesh repair by a laparo-endoscopic approach is suggested for femoral hernias provided expertise is available. All complications of groin hernia management are discussed in an extensive chapter on the topic. Overall, the incidence of clinically significant chronic pain is in the 10-12% range, decreasing over time. Debilitating chronic pain affecting normal daily activities or work ranges from 0.5 to 6%. Chronic postoperative inguinal pain (CPIP) is defined as bothersome moderate pain impacting daily activities lasting at least 3 months postoperatively and decreasing over time. CPIP risk factors include: young age, female gender, high preoperative pain, early high postoperative pain, recurrent hernia and open repair. For CPIP the focus should be on nerve recognition in open surgery and, in selected cases, prophylactic pragmatic nerve resection (planned resection is not suggested). It is suggested that CPIP management be performed by multi-disciplinary teams. It is also suggested that CPIP be managed by a combination of pharmacological and interventional measures and, if this is unsuccessful, followed by, in selected cases (triple) neurectomy and (in selected cases) mesh removal. For recurrent hernia after anterior repair, posterior repair is recommended. If recurrence occurs after a posterior repair, an anterior repair is recommended. After a failed anterior and posterior approach, management by a specialist hernia surgeon is recommended. Risk factors for hernia incarceration/strangulation include: female gender, femoral hernia and a history of hospitalization related to groin hernia. It is suggested that treatment of emergencies be tailored according to patient- and hernia-related factors, local expertise and resources. Learning curves vary between different techniques. Probably about 100 supervised laparo-endoscopic repairs are needed to achieve the same results as open mesh surgery like Lichtenstein. It is suggested that case load per surgeon is more important than center volume. It is recommended that minimum requirements be developed to certify individuals as expert hernia surgeon. The same is true for the designation "Hernia Center". From a cost-effectiveness perspective, day-case laparoscopic IH repair with minimal use of disposables is recommended. The development and implementation of national groin hernia registries in every country (or region, in the case of small country populations) is suggested. They should include patient follow-up data and account for local healthcare structures. A dissemination and implementation plan of the guidelines will be developed by global (HerniaSurge), regional (international societies) and local (national chapters) initiatives through internet websites, social media and smartphone apps. An overarching plan to improve access to safe IH surgery in low-resource settings (LRSs) is needed. It is suggested that this plan contains simple guidelines and a sustainability strategy, independent of international aid. It is suggested that in LRSs the focus be on performing high-volume Lichtenstein repair under local anesthesia using low-cost mesh. Three chapters discuss future research, guidelines for general practitioners and guidelines for patients.

CONCLUSIONS

The HerniaSurge Group has developed these extensive and inclusive guidelines for the management of adult groin hernia patients. It is hoped that they will lead to better outcomes for groin hernia patients wherever they live. More knowledge, better training, national audit and specialization in groin hernia management will standardize care for these patients, lead to more effective and efficient healthcare and provide direction for future research.

Evidence-Based Hernia Treatment in Adults

BACKGROUND

Inguinal hernia repair is the most common general surgical procedure in industrialized countries, with a frequency of about 200 operations per 100 000 persons per year. Suture- and mesh-based techniques can be used, and the procedure can be either open or minimally invasive.

METHODS

This review is based on a selective search of the literature, with interpretation of the published findings according to the principles of evidence-based medicine.

RESULTS

Inguinal hernia is diagnosed by physical examination. Surgery is not necessarily indicated for a primary, asymptomatic inguinal hernia in a male patient, but all inguinal hernias in women should be operated on. For hernias in women, and for all bilateral hernias, a laparoscopic or endoscopic procedure is preferable to an open procedure. Primary unilateral hernias in men can be treated either by open surgery or by laparoscopy/endoscopy. Patients treated by laparoscopy/endoscopy develop chronic pain less often than those treated by open surgery. A mesh-based repair is generally recommended; this seems reasonable in view of the pathogenesis of the condition, which involves an abnormality of the extracellular matrix.

CONCLUSION

The choice of procedure has been addressed by international guidelines based on high-level evidence. Surgeons should deviate from their recommendations only in exceptional cases and for special reasons. Guideline conformity implies that hernia surgeons must master both open and endoscopic/laparoscopic techniques.

Development of a fiber-based membraneless hydrogen peroxide fuel cell

Polyvinylidene fluoride (PVDF) electrospun nano-fiber is suggested as the substrate material for developing biocompatible membraneless hydrogen peroxide fuel cells.

Early safety and efficacy outcomes of a novel technique of sacrocolpopexy for the treatment of apical prolapse

OBJECTIVE

To assess the safety and efficacy of a modified technique of bilateral abdominal sacrocolpopexy in which both uterosacral ligaments are replaced with polyvinylidene fluoride mesh to provide support to the cervix (cervico-sacropexy [CESA]) or vaginal vault (vagino-sacropexy [VASA]).

METHODS

A retrospective observational study was undertaken of women with posthysterectomy vault prolapse or recurrent apical prolapse following previous prolapse repair who underwent bilateral sacrocolpopexy between July 1, 2013, and December 31, 2014, in a tertiary referral unit in the UK. Before surgery and 3 months afterwards, prolapse was assessed using the Pelvic Organ Prolapse Quantification scale and functional outcomes were recorded using the International Consultation on Incontinence Questionnaire for vaginal symptoms and urinary incontinence.

RESULTS

Fifty women were included. At 3 months, 47 (94%) patients reported no bulge symptoms and the mean point C was -7.6. Complications comprised bladder injury in 1 (2%) and minor wound problems in 3 (6%) patients. No mesh erosion was reported.

CONCLUSION

Bilateral abdominal sacrocolpopexy seems to be a safe and effective option for apical prolapse. Longer-term follow-up is needed to detect prolapse recurrence and mesh-related complications.

TOT 8/4: A Way to Standardize the Surgical Procedure of a Transobturator Tape

Suburethral tapes are placed “tension-free” below the urethra. Several studies reported considerable differences of the distance between urethra and tape. These distances ranged from 1 to 10 mm amongst different patients. This either caused urethral obstruction or had no effect on urinary incontinence. Therefore, we decided to standardize the procedure by placing a Hegar dilator of 8-millimeter diameter in the urethra and another Hegar dilator of 4-millimeter diameter between the urethra and the tape during transobturator tape placement. Using that simple technique, which we named “TOT 8/4,” we observed that 83% of the tapes were placed in the desired distance between 3 and 5 millimeters below the urethra.

Influence of gentamicin-coded PVDF suture material on the healing of intestinal anastomosis in a rat model

PURPOSE

Intestinal anastomosis is a fundamental procedure in general surgery and required to restore intestinal continuity following resection. The aim of this study was to evaluate whether a gentamicin-coated polyvinylidene fluoride (PVDF) suture material has beneficial effect on anastomotic healing.

METHODS

Ninety Sprague-Dawley rats were divided into three groups: a PVDF-suture group, a gentamicin-coated PVDF (GPVDF)-suture group and a control group using Maxon® (polyglycolid-co-trimethylene carbonate). For each animal, a colonic anastomosis was performed. Ten animals from each group were sacrificed on postoperative days 3, 5, and 14. Measurements of anastomotic bursting pressure were performed on days 3 and 5. At each time, collagen type I/III ratio, MMP 2 and MMP-9 expression and the proliferation index (Ki67) were analyzed.

RESULTS

In total, 90 animals underwent surgery without postoperative complications. Bursting strength in the GPVDF group was significantly elevated on day 5. Immunohistochemistry showed significant increase of the collagen type I/III ratio for PVDF and GPVDF on days 3 and 5. MMP2 was significantly increased for PVDF on days 3 and 5 and for GPVDF on day 5. The analysis of MMP9 revealed significant increase compared to control on day 3 and 5 (GPVDF) as well as on day 5 (PVDF). Staining for Ki67 revealed a significant elevation on postoperative day 3 for the PVDF and the GPVDF group.

CONCLUSIONS

The present data shows the feasibility of PVDF as suture material for colonic anastomosis and confirms the ability of gentamicin to increase the stability of colonic anastomosis when used as coating material.

Mesh implants: An overview of crucial mesh parameters

Hernia repair is one of the most frequently performed surgical interventions that use mesh implants. This article evaluates crucial mesh parameters to facilitate selection of the most appropriate mesh implant, considering raw materials, mesh composition, structure parameters and mechanical parameters. A literature review was performed using the PubMed database. The most important mesh parameters in the selection of a mesh implant are the raw material, structural parameters and mechanical parameters, which should match the physiological conditions. The structural parameters, especially the porosity, are the most important predictors of the biocompatibility performance of synthetic meshes. Meshes with large pores exhibit less inflammatory infiltrate, connective tissue and scar bridging, which allows increased soft tissue ingrowth. The raw material and combination of raw materials of the used mesh, including potential coatings and textile design, strongly impact the inflammatory reaction to the mesh. Synthetic meshes made from innovative polymers combined with surface coating have been demonstrated to exhibit advantageous behavior in specialized fields. Monofilament, large-pore synthetic meshes exhibit advantages. The value of mesh classification based on mesh weight seems to be overestimated. Mechanical properties of meshes, such as anisotropy/isotropy, elasticity and tensile strength, are crucial parameters for predicting mesh performance after implantation.

A Novel Operative Procedure for Pelvic Organ Prolapse Utilizing a MRI-Visible Mesh Implant: Safety and Outcome of Modified Laparoscopic Bilateral Sacropexy

Introduction. Sacropexy is a generally applied treatment of prolapse, yet there are known possible complications of it. An essential need exists for better alloplastic materials. Methods. Between April 2013 and June 2014, we performed a modified laparoscopic bilateral sacropexy (MLBS) in 10 patients using a MRI-visible PVDF mesh implant. Selected patients had prolapse POP-Q stages II-III and concomitant OAB. We studied surgery-related morbidity, anatomical and functional outcome, and mesh-visibility in MRI. Mean follow-up was 7.4 months. Results. Concomitant colporrhaphy was conducted in 1/10 patients. Anatomical success was defined as POP-Q stage 0-I. Apical success rate was 100% and remained stable. A recurrent cystocele was seen in 1/10 patients during follow-up without need for intervention. Out of 6 (6/10) patients with preoperative SUI, 5/6 were healed and 1/6 persisted. De-novo SUI was seen in 1/10 patients. Complications requiring a relaparoscopy were seen in 2/10 patients. 8/10 patients with OAB were relieved postoperatively. The first in-human magnetic resonance visualization of a prolapse mesh implant was performed and showed good quality of visualization. Conclusion. MLBS is a feasible and safe procedure with favorable anatomical and functional outcome and good concomitant healing rates of SUI and OAB. Prospective data and larger samples are required.

Polyvinylidene Fluoride as a Suture Material: Evaluation of Comet Tail-Like Infiltrate and Foreign Body Granuloma

Background: Biocompatibility and tissue integration of a surgical suture are decisive factors for wound healing and therefore for the success of sutures. The optimal suture material is still under discussion. Polyvinylidene fluoride (PVDF) is described to have superior properties of biocompatibility and is therefore frequently used as a mesh component. Only little information is available about its use as a suture material. The aim of this study was to evaluate the biocompatibility of PVDF as a suture material in comparison to 5 different established sutures in a rat model. Methods: In 30 male rats, a monofilamental PVDF suture (Resopren®) and 5 established control suture materials [polyester (Miralene®), polytetrafluoroethylene (Gore®), poliglecaprone (Monocryl®), polydioxanone (Monoplus®), polyglactin 910 (Vicryl®), USP size 3-0] were placed in the subcutaneous layer of the abdominal wall without knot or tension. After 3, 7 or 21 days, the abdominal walls were explanted for histopathological and immunohistochemical investigation with special regard to the size and quality of foreign body granuloma and the length of the comet tail-like infiltrate (CTI). Results: The PVDF sutures showed the smallest size of foreign body granuloma (60 ± 14 µm) and the smallest CTI length (343 ± 60 µm) of all polymers after 21 days. Only PVDF (Resopren) and polydioxanone (Monoplus) showed a significant collagen I/III ratio increase between days 3 and 21 (p = 0.009 and p = 0.016). The quality of foreign body reaction regarding inflammation, proliferation and fibrotic remodeling was similar between all suture materials. Conclusions: Our data indicate that monofilamental PVDF sutures show a favorable foreign body reaction with small granuloma sizes and CTI length in comparison to established sutures. Its use as a suture material in general surgery could therefore be extended in the future. To reinforce these findings, further clinical studies need to be conducted.

3D non-woven polyvinylidene fluoride scaffolds: fibre cross section and texturizing patterns have impact on growth of mesenchymal stromal cells

Several applications in tissue engineering require transplantation of cells embedded in appropriate biomaterial scaffolds. Such structures may consist of 3D non-woven fibrous materials whereas little is known about the impact of mesh size, pore architecture and fibre morphology on cellular behavior. In this study, we have developed polyvinylidene fluoride (PVDF) non-woven scaffolds with round, trilobal, or snowflake fibre cross section and different fibre crimp patterns (10, 16, or 28 needles per inch). Human mesenchymal stromal cells (MSCs) from adipose tissue were seeded in parallel on these scaffolds and their growth was compared. Initial cell adhesion during the seeding procedure was higher on non-wovens with round fibres than on those with snowflake or trilobal cross sections. All PVDF non-woven fabrics facilitated cell growth over a time course of 15 days. Interestingly, proliferation was significantly higher on non-wovens with round or trilobal fibres as compared to those with snowflake profile. Furthermore, proliferation increased in a wider, less dense network. Scanning electron microscopy (SEM) revealed that the MSCs aligned along the fibres and formed cellular layers spanning over the pores. 3D PVDF non-woven scaffolds support growth of MSCs, however fibre morphology and mesh size are relevant: proliferation is enhanced by round fibre cross sections and in rather wide-meshed scaffolds.

Biomechanical analyses of prosthetic mesh repair in a hiatal hernia model

Recurrence rate of hiatal hernia can be reduced with prosthetic mesh repair; however, type and shape of the mesh are still a matter of controversy. The purpose of this study was to investigate the biomechanical properties of four conventional meshes: pure polypropylene mesh (PP-P), polypropylene/poliglecaprone mesh (PP-U), polyvinylidenefluoride/polypropylene mesh (PVDF-I), and pure polyvinylidenefluoride mesh (PVDF-S). Meshes were tested either in warp direction (parallel to production direction) or perpendicular to the warp direction. A Zwick testing machine was used to measure elasticity and effective porosity of the textile probes. Stretching of the meshes in warp direction required forces that were up to 85-fold higher than the same elongation in perpendicular direction. Stretch stress led to loss of effective porosity in most meshes, except for PVDF-S. Biomechanical impact of the mesh was additionally evaluated in a hiatal hernia model. The different meshes were used either as rectangular patches or as circular meshes. Circular meshes led to a significant reinforcement of the hiatus, largely unaffected by the orientation of the warp fibers. In contrast, rectangular meshes provided a significant reinforcement only when warp fibers ran perpendicular to the crura. Anisotropic elasticity of prosthetic meshes should therefore be considered in hiatal closure with rectangular patches.

Elongation of textile pelvic floor implants under load is related to complete loss of effective porosity, thereby favoring incorporation in scar plates

Use of textile structures for reinforcement of pelvic floor structures has to consider mechanical forces to the implant, which are quite different to the tension free conditions of the abdominal wall. Thus, biomechanical analysis of textile devices has to include the impact of strain on stretchability and effective porosity. Prolift(®) and Prolift + M(®), developed for tension free conditions, were tested by measuring stretchability and effective porosity applying mechanical strain. For comparison, we used Dynamesh-PR4(®), which was designed for pelvic floor repair to withstand mechanical strain. Prolift(®) at rest showed moderate porosity with little stretchability but complete loss of effective porosity at strain of 4.9 N/cm. Prolift + M(®) revealed an increased porosity at rest, but at strain showed high stretchability, with subsequent loss of effective porosity at strain of 2.5 N/cm. Dynamesh PR4(®) preserved its high porosity even under strain, but as consequence of limited stretchability. Though in tension free conditions Prolift(®) and Prolift + M(®) can be considered as large pore class I meshes, application of mechanical strain rapidly lead to collapse of pores. The loss of porosity at mechanical stress can be prevented by constructions with high structural stability. Assessment of porosity under strain was found helpful to define requirements for pelvic floor devices. Clinical studies have to prove whether devices with high porosity as well as high structural stability can improve the patients' outcome.

Coated meshes for hernia repair provide comparable intraperitoneal adhesion prevention

BACKGROUND

Laparoscopic incisional hernia repair with intraperitoneal mesh is associated with a certain degree of adhesion formation to the mesh. This experimental study examined the efficacy of several coated meshes for adhesion reduction.

METHODS

Five commercially available meshes with a layered coating were placed intraperitoneally in rats and followed up for 90 days: polypropylene and polyester meshes, both coated with absorbable collagen (Parietene Composite and Parietex Composite, respectively), and three polypropylene meshes respectively coated with absorbable omega-3 fatty acids (C-Qur Edge), absorbable cellulose (Sepramesh IP), and nonabsorbable expanded polytetrafluoroethylene (Intramesh T1). Uncoated polypropylene and collagen meshs (Parietene and Permacol, respectively) served as the control condition. Adhesions, incorporation, and tissue reaction were evaluated macro- and microscopically. Additionally, the development of the neoperitoneum was examined.

RESULTS

All the coated meshes performed equally well in terms of adhesion reduction. The collagen mesh performed comparably, but the uncoated polypropylene mesh performed significantly worse. The different coatings led to very differing degrees of inflammation. Ingrowth was observed only at the place of suture but was comparable for all the meshes except C-Qur Edge, which showed the weakest incorporation. Development of a neoperitoneum on the mesh surface occurred independently of whether an absorbable or nonabsorbable coating or no coating at all was present.

CONCLUSIONS

Commercially available meshes with a layered coating deliver comparable adhesion reduction. The physical presence of a layered coating between the intraperitoneal content and the abdominal wall seems to be more important than the chemical properties of the coating in adhesion formation.

Laparoscopic pectopexy: a randomised comparative clinical trial of standard laparoscopic sacral colpo-cervicopexy to the new laparoscopic pectopexy. Short-term postoperative results

PURPOSE

Sacral colpopexy is a well established method of vaginal prolapse correction. Although it is capable of restoring the physiologic axis of the vagina, this method also bears some serious operative risks [1]. The aim of the study was to compare the laparoscopic sacral colpopexy with a laparoscopic bilateral fixation of the vagina/cervix to the iliopectineal ligaments via a PVDF-mesh (pectopexy).

METHODS

This part of a single-center randomized prospective clinical trial (Canadian Task Force Classification) compared the short-term operative outcome of laparoscopic sacropexy and pectopexy. We evaluated the operating time, blood loss, hospital stay duration, occurrence of major complications, episodes of constipation, urinary retention, de novo urinary incontinence, urinary tract infections, body mass index and postoperative Creactive protein values. The 1-year follow up examination will be carried out to evaluate the occurrence of relapse as well as late complications. Local symptoms and sexual activity will be evaluated using a German version of the ICIQ Vaginal Symptoms Questionnaire.

RESULTS

We carried out 43 pectopexies and 40 sacropexies in conjunction with other laparoscopic and/or vaginal procedures, as indicated. No major complications occurred in both groups during the hospital stay. There were no significant differences in the body mass index, average age, hospital stay duration and occurrence of constipation. The average operating time (43.1 vs. 52.1 min) and blood loss (4.6 vs. 15.3 ml) were significantly lower in the pectopexy group (p < 0.001).

CONCLUSION

Although laparoscopic pectopexy cannot yet be generally recommended as an alternative to sacropexy until the follow-up data is obtained, the new method can be considered in patients where the presacral preparation bears a higher risk of injury.