Biomechanical Properties Of Vaginal Wall In Women With Vaginal Anterior Wall And Study On The Changes Of Histocompatibility And Biomechanical Properties Of Three Kinds Of Synthetic Mesh Implanted In Rabbit Abdominal Wall And Vagina

Objective:To assess the biomechanical properties of anterior vaginal tissue from postmenopausal women with anterior vaginal prolapse (AVP), and to explore the influence of AVP on biomechanical properties of anterior vaginal tissue.Methods:Anterior vaginal tissue was obtained at the time of prolapse surgery in 16 postmenopausal women with severe AVP (AVP group) and from 16 fresh female cadavers (control group). Tissue specimens were biomechanically assessed by a puller system, and load-elongation curves were digitally recorded. The results, including stress-strain, stiffness, elastic modulus, tensile strength, breaking load of vaginal tissue and maximum elongation percentage have analyzed in order to define the characteristics of the mechanical properties of anterior vaginal tissue.Results:(1) There was no difference in stiffness and elastic modulus in the toe region of the load-elongation curve between AVP group and control group (0.36±0.14 vs.0.34±0.11 N/mm, P=0.546; 0.32±0.22 vs.0.24±0.08 MPa, P=0.171).(2) There was significant difference in stiffness and elastic modulus in the linear region of the load-elongation curve between AVP group and control group (8.07±3.20 vs.3.71 ±2.73 N/mm, P＜0.001; 6.41±2.41 vs.2.63±1.92 MPa, P<0.001).(3) Breaking load and tensile strength of vaginal tissue in AVP group were significantly higher than that in control group (35.12±18.72 vs.19.24±11.06 N, P=0.007; 2.10± 0.97 vs.0.94±0.54 MPa, P<0.001).(4) There was no significant difference in maximum elongation percentage between AVP group and control group (73.04% vs.78.72%, P=0.305).(5) There was no significant difference in biomechanical properties between transverse and longitudinal vaginal tissue (P>0.05).Conclusions:Women with AVP present degeneration of biomechanical properties in vaginal tissue. The biomechanical behavior of vaginal wall is isotropic biomechanical.Objective:The objective of the study was to assess histologic response and changes in the mechanical properties of three synthetic clinical prolapse meshes following implanted in abdomen and vagina in rabbits after 30 and 90 days.Methods:In this investigator-initiated prospective-controlled experimental study, the basic properties of the partially absorbable meshes (ArtisynTM Y mesh) and super lightweight meshes (Alyte Y mesh), including tissue biocompatibility and mechanical properties were evaluated and compared with conventional polypropylene meshes (GynemeshTM PS) pre and post-implanted in a rabbit model. Thirty New Zealand white rabbits were included in this study (n=5/mesh type/group). At 30 and 90 days after surgery, mesh-tissue complex specimens were subjected to histological studies and biomechanical properties evaluation. Histologic evaluation of the samples under light microscopy included the following parameters:inflammation, neovascularization, and fibroblastic proliferation. Tissue specimens were biomechanically assessed by a puller system, and load-elongation curves were digitally recorded. The results, including stiffness and elastic modulus in toe region and linear region, tensile strength, breaking load of vaginal tissue and maximum elongation percentage have analyzed in order to define the characteristics of the mechanical properties of the pre-implanted mesh types and explanted mesh-tissue complex specimens.Results:(1) Abdominal grafts had a lower mesh exposure rate than vaginal grafts (3.3% vs. 16.67%), but with no significant difference (P=0.195).(2) After 30 days, abdominal grafts had lower scores for inflammation (1.59±0.09 vs. 1.881±0.08, P=0.015) and neovascularization (1.49±0.07 vs.1.95±0.08, P<0.001), and had higher scores for fibroblastic proliferation (2.08±0.08 vs.1.68±0.07, P<0.001) than vaginal grafts.(3) Score of inflammation (abdominal grafts):Alyte mesh (1.16±0.15)<Gynemesh mesh (1.54±0.12)<Artisyn mesh (2.08±0.13), with significant difference (P=0.048, P<0.001).(4) After implanted for 90 days, both of the abdominal grafts and vaginal grafts have lower scores for inflammation than implanted for 30 days (P=0.012, P=0.001).(5) Following 30 days of implantation, compared with the mesh-tissue complex, the mechanical properties of some mesh types altered, with significant decreases in stiffness and elastic modulus in toe region (0.57±0.11 vs.0.42±0.11 N/mm, P=0.001; 2.91±1.15 vs.0.7010.25 MPa, P<0.001), and increases in stiffness in linear region (2.41±0.59 vs. 3.45±1.18 N/mm, P=0.006), and decreases in elastic modulus in linear region (12.17± 4.91 vs.5.53±1.90 MPa, P<0.001).(6) After 90 days, compared with 30 days, these changes still exist.(7) Similar stiffness in linear region and maximum elongation percentage of formed mesh-tissue complexes were observed for mesh types of different pre-implant stiffness and structure after 90 days implantation.Conclusions:(1) The three clinical meshes have good tissue biocompatibility in abdominal and vaginal region.(2) After 30 days, abdominal grafts had lower scores for inflammation and neovascularization, and had higher scores for fibroblastic proliferation than vaginal grafts.(3) Super lightweight meshes have less foreign material, and have a lower histologic inflammation response. Partially absorbable meshes have a higher histologic inflammation response. After 90 days, the scores of inflammation of the three clinical meshes have no significant difference.(4) There are some changes in the mechanical properties of implants meshes formed mesh-tissue complex.(5) Similar stiffness in linear region and maximum elongation percentage of formed mesh-tissue complexes of the three meshes after 90 days implantation.Objective:The purpose of this study was to measure changes in biomechanical properties of rabbit pelvic floor tissue over 48 hours post-mortem using rabbit gemellus tendons under simulated morgue conditions.Methods:Forty New Zealand white rabbits were euthanized and then the gemellus tendons were obtained. The gemellus tendons were obtained from each rabbit immediately post-mortem, and then stored at a constant temperature of 0-4 degrees Celsius for the remainder of the study. Firstly at 2 hours, then at 12 hours,24 ours,36 hours and 48 hours. Tissue specimens were biomechanically assessed by a puller system, and load-elongation curves were digitally recorded. The results, including stiffness and elastic modulus in toe region and linear region, tensile strength, breaking load of vaginal tissue and maximum elongation percentage were analyzed.Results:There was no significant difference in stiffness (0.57、0.94、0.89、0.74、0.70 N/mm) and elastic modulus (1.49、2.43、2.32、1.92、1.82 MPa) in the toe region between the 5 groups. There was no significant difference in stiffness (15.70.12.59. 10.53、11.81、13.48 N/mm) and elastic modulus (40.79、32.69、27.22、30.75、 34.26 MPa) in the linear region between the 5 groups. There was no significant difference in breaking load (45.58、39.03、40.33、47.62、43.42 N), tensile strength (5.97、5.21、5.19、6.10、5.70 MPa) and the maximum elongation percentage (35.87、33.24、33.59、36.33、37.12%) between the 5 groups.Conclusions:This data provides support that gemellus tendons obtained from fresh dead rabbits may be used for biomechanical for up to 48 hours. This information may allow investigators access to muscle tissue that might have been impossible to obtain via surgery or unable to be tested due to fixation.