Comparaison de différents biomatériaux destinés à la chirurgie vaginale dans un modèle in vivo d'infection de prothèse chez le rat

Acute in vivo response to an alternative implant for urogynecology

Purpose. To investigate in vivo the acute host response to an alternative implant designed for the treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP). Methods. A biodegradable scaffold was produced from poly-L-lactic acid (PLA) using the electrospinning technique. Human and rat adipose-derived stem cells (ADSCs) were isolated and characterized by fluorescence-activated cell sorting and differentiation assays. PLA scaffolds were seeded and cultured for 2 weeks with human or rat ADSCs. Scaffolds with and without human or rat ADSCs were implanted subcutaneously on the abdominal wall of rats. After 3 and 7 days, 6 animals from each group were sacrificed. Sections from each sample were analyzed by Haematoxylin and Eosin staining, Sirius red staining, and immunohistochemistry for CD68, PECAM-1, and collagen I and III. Results. Animals responded to the scaffolds with an acute macrophage response. After 7 days of implantation, there was extensive host cell penetration, new blood vessel formation, and new collagen deposition throughout the full thickness of the samples without obvious differences between cell-containing and cell-free scaffolds. Conclusions. The acute in vivo response to an alternative implant (both with and without cells) for the treatment of SUI and POP showed good acute integration into the host tissues.

A comparison of the incidence of early postoperative infections between patients using synthetic mesh and those undergoing traditional pelvic reconstructive surgical procedures

New mesh-related complications such as erosion, etc., can result from abnormal postoperative healing due to surgical site infection. The aim of our study was to compare systemic inflammatory responses and the incidence of early infectious complications after reconstructive surgery using synthetic mesh and after traditional vaginal wall repair. In this prospective observational study 99 women with symptomatic pelvic organ prolapse were included; 55 women underwent traditional repair and 44 repair using mesh. After the procedure infectious complications were monitored. The patients who underwent reconstructive surgery using mesh material were more likely to have febrile morbidity in the postoperative period than the patients who had been treated with traditional repair (p=0.031); there was a higher incidence of combination febrile morbidity with elevated C-reactive protein (CRP) > 50 mg/l; p=0.046, and a higher incidence of CRP increase over 30 mg/l; p=0.005. Reconstructive procedures using synthetic mesh are accompanied by a higher incidence of early post-operative infectious complications.

Is degradable antibiotic coating for synthetic meshes provide protection against experimental animal infection after fascia repair?

The surgical repair of pelvic organ prolapse using synthetic mesh can fail because of slow or partial implant integration due to poor biocompatibility or infection. As systemic antibiotic prophylaxis has only limited success, we have developed a system that coats standard polypropylene mesh with clinically relevant antibiotics. Amoxicillin and ofloxacin are both released from the mesh in vitro at high levels over 3 days, preventing adhesion and biofilm formation by a clinical isolate of E. coli. In an in vivo incisional hernia repair model in rats, the antibiotic-coated mesh results in appropriate tissue integration with adequate vascularization and collagen formation. When implanted animals are infected with virulent E. coli, both antibiotic coatings provide full protection against infection (as assessed both clinically and microbiologically), thus demonstrating their bioavailability. This method is a specific approach for producing a therapeutic coating that could reduce postsurgical infections.

Late polypropylene mesh susceptibility to infection during intra-abdominal sepsis

PURPOSE

To evaluate the susceptibility of high-density polypropylene mesh to contamination, 1 year after experimental hernia repair.

METHODS

Wistar rats were randomized into two groups: one experimental group (n = 20) and another control group (n = 10). Mesh hernia repair was performed with intra-abdominal (group I, n = 10) or subcutaneous (group II, n = 10) implantation of grafts. The three groups were exposed to an intra-abdominal E. coli administration after 1 year of operation. After 24 hr, the meshes and peritoneum were sampled from the experimental and control groups, respectively, in order to assess bacterial inoculation. Immunoreaction to E. coli inoculation was also evaluated after 24 hr by measuring serum interleukin-6 (IL-6) and C-reactive protein (CRP) levels.

RESULTS

Bacteriological analysis revealed increased contamination in groups I and II when compared with the control group (p = .001 and .007, respectively). IL-6 levels were increased in both groups I and II compared with the control group, 24 hr after E. coli injection (p = .034 and .022, respectively), while there was no statistically significant difference between groups concerning the concentration of CRP.

CONCLUSIONS

Polypropylene mesh is vulnerable to bacterial inoculation during intra-abdominal sepsis 1 year after mesh placement.

Mechanical evaluation of synthetic biomaterials used in the correction of pelvic floor disorders--experimental study in rabbits

OBJECTIVE

To evaluate the biomechanical properties of the principal prosthetic materials currently used in genital prolapse surgery.

STUDY DESIGN

Based on an animal model of incisional abdominal hernia, 40 adult rabbits were implanted. Four 2.5 cm x 2.5 cm parietal defects, were created in the abdominal fascia and muscles while respecting the peritoneum. For each rabbit, the defect was repaired by four different large pore size prostheses which varied according to the material used: two with monofilament of heavy (75 g/m(2)) or low (38 g/m(2)) weight polypropylene (PP), and two with multifilament of heavy (115 g/m(2)) or low (59 g/m(2)) weight polyethylene-terephthalate (PET). Animals were sacrificed in groups of 10 after 14, 30, 90 and 180 days to evaluate contraction, solidity and elasticity of the prostheses.

RESULTS

PP and PET retracted, independently of their weight, in 81.25% and 20% respectively. Intensity of contraction was not predictable but median value of retracted surface was 14% with PP, none with PET. Contraction settled quickly after tissue integration and did not subsequently occur. Heavyweight PET was considered the most solid material (70 N cm(-1)), low-weight PP the most fragile (20 N cm(-1)). Heavy forms of PP or PET resisted better to the rupture than the light forms which were sometimes insufficient to resist the extreme values of the human abdominal pressure (16 N cm(-1)). PP was more flexible than PET, but PET was the only form which was able to support extreme values of the abdominal pressure and remain in the elastic range. Duration of implantation did not modify solidity or elasticity of the prostheses.

CONCLUSION

In our abdominal rabbit model, as regards mechanical properties, heavyweight PET seems to be the optimal biomaterial.

[Transobturator subvesical mesh: Tolerance and mild-term results. A prospective study]

AIM

To evaluate midterm results, tolerance and efficiency of interposition of a transobturator subvesical mesh for the repair of cystoceles.

PATIENTS AND METHODS

We report the results of a total of 45 consecutive transobturator mesh fixation between March 1, 2005 and March 1, 2007. We used a transvaginal polypropylen tension-free mesh (Prolène, Ethicon, Johnson & Johnson, France) fixed through the obturator foramen.

RESULTS

Before surgery, all patients had cystocele of more or equal than grade II, according to Baden and Walker classification. Five had grade II cystocele (11%), 36 had grade III (80%) and four grade IV (9%). Thirty-nine women had associated median and/or posterior prolapse (86%). Eleven women had urinary incontinence (24%). The procedure was performed in all cases. Duration of a cystocele cure procedure was 25minutes+/-3.2 (12-32). Mean follow-up was 18 months+/-4.2 (13-29). Vaginal erosion ratio was 6%. There was no mesh infection. The objective success rate was 93%. The satisfaction index was 70%.

CONCLUSION

Transobturator mesh is a safe and efficient method for anterior segment prolapse repair. This procedure is simple, mini-invasive, reproducible and efficient with low morbidity and good tolerance.