Biological behavior of polypropylene meshes suitable for intra-abdominal implantation in animal model

The expected incisional hernia rate is between 11-20% after laparotomy. Using mesh repair the results of the hernioplasty have recently improved. However the complication of mesh implants--especially in intraperitoneal position--can be life threatening. Additionally the appropriate mesh is expensive. We tried to create a mesh, which can be used intraperitoneally and generates adhesion in the abdominal wall, but keeps the intraabdominal organs adhesion free. Our experiments were divided into four groups. In the first we used different materials to cover the intraperitoneal side of polypropylene mesh. In the second phase three different pore-sized meshes were compared. In the third part the biological behavior of three different material-reduced meshes were investigated. Based on our previous results in the last session we used only silicone membrane protected material-reduced polypropylene meshes to cover the abdominal defects. Our experiments have shown that intraperitoneal implant with silicone-covered Vypro (Ethicon)/Premilene (B. Braun Medical) mesh significantly decreases the formations of adhesion.     

Adhesion formation of a polyvinylidenfluoride/polypropylene mesh for intra-abdominal placement in a rodent animal model

Background  Effective laparoscopic ventral herniorrhaphy mandates the use of an intraperitoneal mesh. Visceral adhesions and shrinkage of prosthetics may complicate repairs. The aim of this study was to compare adhesion formation, mesh shrinkage and tissue ingrowth after intra-abdominal placement of a novel two-component monofilament mesh structure made of polypropylene (PP) and polyvinylidenfluoride (PVDF) with current alternatives. Materials and methods  Forty Sprague-Dawley rats were used in this study. Mesh samples were fixed as intra-abdominal only mesh at the right lateral abdominal wall. The study groups were: PVDF+PP (polypropylene parietally and polyvinylidenfluoride viscerally), PP+Col (polypropylene with a collagenoxidized film), ePTFE (smooth surface viscerally and a textured surface parietally), and PP (a pure polypropylene mesh serving as control). The meshes were explanted after 30 days. Adhesions were scored as a percentage of explanted biomaterials’ affected surface area; prosthetic shrinkage was calculated. Foreign-body reaction to mesh materials was measured by investigating the amount of inflammatory infiltrate and fibrotic tissue formation. Results  In terms of adhesion score, the pure PP mesh showed the highest values followed by the ePTFE, PVDF+PP, and PP+Col meshes. Quantitative assessment of adhesion area revealed a significantly higher value of the pure PP mesh sample (62.0 ± 22.1%) compared with the PP+Col (26.8 ± 12.1%) and the PVDF+PP mesh (34.6 ± 8.2%). Percentage of shrinkage showed a significantly higher value of the ePTFE mesh (52.4 ± 13.9%) compared with all other mesh modifications (PP+Col 19.8 ± 13.9%, PVDF+PP 19.9 ± 7.0%, and PP 26.8 ± 9.5%). Inflammatory infiltrate was significantly reduced in the PVDF+PP mesh group compared with all other mesh samples. Conclusion  The use of the novel two-component monofilament mesh structure made of polypropylene and polyvinylidenfluoride was found to be favorable regarding adhesion formation and mesh shrinkage compared to conventional mesh materials used for intra-abdominal placement.     

Evaluation of intraperitoneal placement of absorbable and nonabsorbable barrier coated mesh secured with fibrin sealant in a New Zealand white rabbit model

Background  

This study aimed to evaluate the acute and chronic fixation strength of fibrin sealant (FS) as an alternative method of fixation for laparoscopic ventral hernia repair (LVHR).     

Novel technique of overlaying a poly-l-lactic acid nanosheet for adhesion prophylaxis and fixation of intraperitoneal onlay polypropylene mesh in a rabbit model

Background

One problem with polypropylene mesh (PPM) used to repair abdominal wall hernias is dense adhesions to the visceral surface. The authors developed the biocompatible poly-l-lactic acid (PLLA) nanosheet (thickness?Methods The PLLA nanosheet was fabricated by the spin-coating method and peeling technique with polyvinyl alcohol (PVA) as a supporting film. Two 1.5-cm-square pieces of mesh were implanted on each peritoneal side of the midline incision. The mesh was fixed to the peritoneum with a suture and then overlaid with a 4-cm-square piece of Seprafilm or nanosheet. To examine the fixative property, mesh was overlaid with Seprafilm or nanosheet without a fixed suture. After 4?weeks, mesh adhesion, inflammatory reaction, fixation, and dislocation of mesh were evaluated.

Results

Nanosheet-overlaid meshes were flexible and fit over the peritoneum. Adhesion was observed in 10% of the nanosheet-overlaid meshes and in 50% of the Seprafilm-overlaid meshes. The adhesion tenacity grade was significantly lower with the nanosheet-overlaid meshes (0.1?±?0.1) than with the Seprafilm-overlaid meshes (1.0?±?0.4) (p?=?0.029), and the percentage of the adhesion area also was lower with the nanosheet-overlaid meshes (1.0?±?1.0% vs 8.5?±?3.2%; p?=?0.037). The mean inflammatory cell counts were lower with the nanosheet-overlaid meshes (p?=?0.0023). Regarding the fixative property, 37.5% of the nanosheet-overlaid meshes were fixated on the peritoneum, but no Seprafilm-overlaid mesh was fixated.

Conclusion

Overlaying of a PLLA nanosheet was effective for adhesion prophylaxis of intraperitoneal mesh. It also may have a possible beneficial effect on fixation of mesh.     

Prevention of adhesions to polypropylene mesh in a rabbit model

The purpose of this study was to develop a quantitative model for evaluating adhesion formation and to determine whether Seprafilm (HAL-F) bioresorbable membrane (Genzyme Corp., Cambridge, MA) is effective in preventing adhesions to polypropylene mesh (PPM). PPM has been shown to be an effective material for the repair of abdominal wall defects. One disadvantage of PPM is its tendency to form dense adhesions when in contact with abdominal viscera. HAL-F, a sodium hyaluronate/carboxymethylcellulose absorbable membrane, has been shown to prevent adhesion formation after midline closures. Its efficacy in preventing adhesions to PPM has not been examined previously. A 5 x 7-cm anterior abdominal wall defect was created in 24 New Zealand White rabbits. This defect was then repaired with PPM. In the experimental group, a 5 x 7-cm piece of HAL-F was placed between the mesh and the abdominal viscera. At 30 days, the animals were killed and adhesions were categorized and quantified using digital image analysis of inked specimens. The strength of mesh incorporation into surrounding tissues was also examined using an Instron tensiometer. The formation of adhesions between the viscera and mesh repair was significantly reduced by the use of HAL-F. The surface area involved for bowel adhesions was reduced 94 per cent (P = 0.00132). The strength of incorporation was not adversely affected. HAL-F is highly effective in preventing adhesions to PPM, without adversely effecting the strength of mesh incorporation.     

Fibrin glue reduces intra-abdominal adhesions to synthetic mesh in a rat ventral hernia model

Postoperative intra-abdominal adhesions are associated with significant morbidity and mortality. In this study, the effect of topical fibrin glue (FG) on adhesion formation in a rat model was investigated. Forty Sprague-Dawley male rats underwent midline laparotomy. Bilateral peritoneal-muscular abdominal wall defects were created and then replaced with premeasured soft tissue Goretex patches. Rats were randomized to FG sprayed over the patches or to a control group. Two observers blinded to the randomization assessed the severity of adhesions to the patch by scoring the density of adhesions (grades 0-3) and the percentage of the patch area covered by adhesions (0-100%). The mean percentage of the patch covered by adhesions was 32.8 +/- 6.1 per cent for the FG group versus 57.9 +/- 6.7 per cent for the control group (P < 0.01). The mean density of adhesions for the FG group was 0.95 (+/-0.17) versus 2.0 (+/-0.21) for the control group (P = 0.001). Topical FG reduces the severity and density of intra-abdominal adhesions in a rat model.     

Histologic evaluation of absorbable and non-absorbable barrier coated mesh secured to the peritoneum with fibrin sealant in a New Zealand white rabbit model

Purpose  

The purpose of this study is to evaluate the histologic response to fibrin sealant (FS) as an alternative fixation method for laparoscopic ventral hernia repair.     

Fibrin glue for intraperitoneal laparoscopic mesh fixation: a comparative study in a swine model

Background  

The classic method of mesh fixation in laparoscopic ventral hernia repair is transfascial sutures with tacks. This method has been associated with low recurrence rates, but yields significant morbidity from pain and bleeding. Fibrin glue has been used successfully in inguinal hernia repair with decreased incidence of chronic pain without an increase in recurrence rates, but its utility for laparoscopic ventral hernia repair is unknown. Our aim is to evaluate the efficacy of fibrin glue for laparoscopic mesh fixation to the anterior abdominal wall compared with other fixation methods.     

Evaluation of fibrin sealant for biologic mesh fixation at the hiatus in a porcine model

Background

The ideal method to secure biologic mesh during laparoscopic hiatal hernia repair remains uncertain. Suture or tack fixation can be technically difficult, and serious cardiovascular complications have been reported. Fibrin sealant (FS) offers a potential solution to this problem. We hypothesized that FS provides comparable mesh fixation to suture repair during laparoscopic mesh hiatoplasty.

Study design

Using a porcine model, laparoscopic hiatal hernia repair was performed with suture reapproximation of the crura and reinforcement with an acellular porcine dermal matrix. Prior to repair, animals were randomized to mesh fixation with sutures (S) or FS. After 30-day survival, an esophagram was performed, the diaphragm harvested, and mesh position, fixation, and incorporation were evaluated histologically and biomechanically using a T-peel test.

Results

Twenty (10 S and 10 FS) laparoscopic hiatal hernia repairs were performed. Total operative time was significantly less in the FS group (74.7 versus 127.0?min, p?<?0.01). There were no instances of mesh migration in any animal. Mean peel force did not differ significantly between the S and FS groups (0.21 vs. 0.18?N/mm, respectively; p?=?0.49). There was no significant difference in cellular repopularization or inflammatory changes around the mesh.

Conclusions

Fibrin sealant offers a reasonable alternative to suturing biologic mesh during laparoscopic hiatal hernia repair with equivalent mesh fixation. At 30 days it provides adhesive strength similar to suture fixation, while significantly reducing operative time.     

Evaluation of acute fixation strength of absorbable and nonabsorbable barrier coated mesh secured with fibrin sealant

Introduction  

The purpose of this study was to evaluate the acute fixation strength of fibrin sealant as an alternative fixation method for laparoscopic ventral hernia repair (LVHR) when utilized with absorbable and nonabsorbable barrier meshes.     

Prospective evaluation of adhesion formation and shrinkage of intra-abdominal prosthetics in a rabbit model

Laparoscopic ventral hernia repair requires an intraperitoneal prosthetic; however, these materials are not without consequences. We evaluated host reaction to intraperitoneal placement of various prosthetics and the functional outcomes in an animal model. Mesh (n = 15 per mesh type) was implanted on intact peritoneum in New Zealand white rabbits. The mesh types included ePTFE (DualMesh), ePTFE and polypropylene (Composix), polypropylene and oxidized regenerated cellulose (Proceed), and polypropylene (Marlex). Adhesion formation was evaluated at 1, 4, 8, and 16 weeks using 2-mm mini-laparoscopy. Adhesion area, adhesion tenacity, prosthetic shrinkage, and compliance were evaluated after mesh explantation at 16 weeks. DualMesh had significantly less adhesions than Proceed, Composix, or Marlex at 1, 4, 8, and 16 weeks (P < 0.0001). Marlex had significantly more adhesions than other meshes at each time point (P < 0.0001). There were no statistically significant differences in adhesions between Proceed and Composix meshes. After mesh explantation, the mean area of adhesions for Proceed (4.6%) was less than for Marlex (21.7%; P = 0.001). The adhesions to Marlex were statistically more tenacious than the DualMesh and Composix groups. Overall prosthetic shrinkage was statistically greater for DualMesh (34.7%) than for the remaining mesh types (P < 0.01). Mesh compliance was similar between the groups. Prosthetic materials demonstrate a wide variety of characteristics when placed inside the abdomen. Marlex formed more adhesions with greater tenacity than the other mesh types. DualMesh resulted in minimal adhesions, but it shrank more than the other mesh types. Each prosthetic generates a varied host reaction. Better understanding of these reactions can allow a suitable prosthetic to be chosen for a given patient in clinical practice.     

Prospective histologic evaluation of intra-abdominal prosthetics four months after implantation in a rabbit model

Background

Placement of an intraperitoneal prosthetic is required for laparoscopic ventral hernia repair. The biocompatibility of these prosthetics determines the host’s inflammatory response, scar plate formation, tissue ingrowth, and subsequent mesh performance, including prosthetic compliance and prevention of hernia recurrence. We evaluated the host response to intraperitoneal placement of several prosthetics currently used in clinical practice.

Methods

A 4-cm × 4-cm piece of mesh was implanted on intact peritoneum in New Zealand white rabbits. The mesh types included expanded polytetrafluoroethylene (ePTFE) (DualMesh^®), ePTFE and polypropylene (Composix^®, heavyweight polypropylene), polypropylene and oxidized regenerated cellulose (Proceed^®, midweight polypropylene), and polypropylene (Marlex^®, heavyweight polypropylene). At four months, standard hematoxylin and eosin and Milligan’s trichrome stains of the mesh-tissue interaction were analyzed by three observers blinded to the mesh types. Each specimen was evaluated for scar plate formation, inflammatory response, and tissue ingrowth. Each of these three categories was graded on a standard scale of 1–4 (1 = normal tissue and 4 = severe inflammatory response). The scores were analyzed using Wilcoxon rank sum test with p < 0.05 as significant.

Results

Ten samples of each mesh type were evaluated. There was no difference in tissue incorporation between the groups. The mean scar plate formation was greater in the heavyweight polypropylene meshes than for DualMesh (p = 0.04). With Proceed, the reduction in scar plate formation compared with that for Composix and Marlex approached statistical significance (p = 0.07). The mean number of inflammatory cells was greater around the ePTFE when compared with the midweight polypropylene (p = 0.02) but equal to the other meshes.

Conclusions

The four prosthetic materials evaluated in this study demonstrate comparable host biocompatibility as evidenced by the tissue ingrowth. Scar plate formation around DualMesh was significantly less than that around Composix and Marlex. Interestingly, more inflammatory cells were noted surrounding the DualMesh which was equal to that of the heavyweight meshes. Proceed, a midweight polypropylene mesh, has the potential for improved patient tolerance compared to heavyweight polypropylene meshes based on its favorable histologic findings.     

不同材质补片固定大鼠膈肌后的炎症反应、粘连及补片皱缩情况对比研究

背景与目的：食管裂孔疝是外科常见病症,临床上多采用补片以无张力修补的方式进行治疗。食管裂孔疝的补片修补中补片的选择及其应用效果方面的实验数据仍相对缺乏。因此,本研究通过在大鼠食道裂孔处膈肌组织上分别固定聚丙烯补片和复合补片,比较两种材质补片对周围组织的影响,以及自身皱缩情况,为临床食管裂孔疝补片的选择提供参考。方法：雄性SD大鼠在分离胃部与肝脏相连接组织显露胃食道裂孔后,分别用单丝缝线将轻量聚丙烯补片（聚丙烯补片组）或复合补片（复合补片组）固定于食道裂孔处膈肌组织,或不进行补片固定（假手术组）。分别在术后7、15、30 d时记录每组每只大鼠的体质量和饮食量。观察30 d后处死大鼠,分析补片皱缩程度、粘连强度以及膈肌组织的病理学变化。结果：各组大鼠手术前后的体质量及每天进食量均无明显的变化（均P>0.05）。复合补片组膈肌组织与补片的粘连范围及粘连程度分值均明显低于聚丙烯补片组（均P<0.05）;两组补片均出现皱缩,但复合补片组术后补片面积明显大于聚丙烯补片组,皱缩率明显低于聚丙烯补片组（均P<0.05）;与假手术组比较,聚丙烯补片组和复合补片组膈肌组织出现局部肌纤维萎...     

Comparison of adhesion formation to intra-abdominal mesh after laparoscopic adhesiolysis in the New Zealand White rabbit

The purpose of this study was to investigate the effects of early adhesiolysis on long-term adhesion formation after the intraperitoneal implantation of polypropylene (PP) mesh and expanded polytetrafluoroethylene (ePTFE) mesh in a rabbit model. Through a small midline laparotomy a 2 x 2-cm piece of mesh (n = 80) was sewn to an intact peritoneum on each side of a midline incision in 40 New Zealand White rabbits. Two types of ePTFE mesh [Dual Mesh (Dual) and modified Dual Mesh (C-Type), W.L. Gore and Associates, Flagstaff, AZ] and PP mesh (Marlex, C.R. Bard, Murray Hill, NJ) were compared. In 10 rabbits (n = 20) a laparoscopic adhesiolysis (LapA) was performed at one week. Mesh adhesions were scored using a modified Diamond scale (0, 0%; 1, 1-25%; 2, 26-50%; and 3, > 50%) at 1, 3, 9, and 16 weeks by serial microlaparoscopic (2 mm) examinations. After recording the final adhesion score at 16 weeks the prosthetic biomaterials were excised en bloc with the anterior abdominal wall for histologic evaluation of mesothelial layer growth (%) on the visceral surface of the mesh. Statistical differences (P value < 0.05) were measured by chi-square and Wilcoxon signed rank tests. There were no statistical differences in mean adhesion scores at adhesiolysis at 7 days. The mean adhesion scores in the groups undergoing laparoscopic adhesiolysis was statistically less (P < 0.05) for PP and both ePTFE meshes at 3-, 9-, and 16-week intervals compared with those not undergoing adhesiolysis. The percentage of mesothelialization on the visceral surface of the mesh was not statistically different between the adhesiolysis and control groups for any of the prosthetic biomaterials. Laparoscopic adhesiolysis at one week minimizes subsequent adhesion formation to PP and ePTFE mesh over a 4-month follow-up. Adhesion formation within the first 7 days after mesh implantation appears to determine the long-term adhesion score. Eliminating adhesions to mesh by mechanical or other means during this critical time may control adhesions to the mesh and subsequent mesh-related complications.     

Histologic assessment of mesh fixation following laser-assisted tissue soldering in a lapine model

OBJECTIVE: Wound histology and mesh bioincorporation following intraperitoneal fixation using laser-assisted soldering was evaluated. METHODS: 2.8-3.2 kg NZW rabbits underwent laparotomy. Controls had 2x2 cm segments of Mersilene stapled to peritoneum. Group 2 segments were affixed with 55% collagen solder onlay by fiber-coupled diode laser (1.43 +/- 10 micro, 2.5 W CW, 4 mm spot, 60 degrees C set temperature). Group 4 had Mersilene inlaid into melted solder. Group 3 had solder-embedded Vicryl mesh affixed. Animals were euthanized at 0, 2, 4, 6 weeks. Fixed sections were assessed for integrity, inflammation, and fibrosis using H & E, Masson's Trichrome and Evans Van Gieson staining. RESULTS: Histology demonstrated cell types, local mesh reaction, and progressive evidence of solder reabsorption mimicking normal healing and bioincorporation. Mersilene groups demonstrated normal arrangement of collagen-rich layers around mesh. CONCLUSION: Collagen-based tissue soldering permits normal wound healing and may mitigate use of staples. Further development of this strategy is warranted.     

Comparative evaluation of adhesion formation, strength of ingrowth, and textile properties of prosthetic meshes after long-term intra-abdominal implantation in a rabbit

BACKGROUND: Effective laparoscopic ventral herniorrhaphy usually mandates the use of an intraperitoneal prosthetic. Visceral adhesions and changes in textile characteristics of prosthetics may complicate repairs, especially long-term. The aim of this study was to compare the adhesion formation, tissue ingrowth, and textile characteristics one year after intra-abdominal placement of the commonly used prosthetic meshes. MATERIALS AND METHODS: Forty (4 x 4 cm) meshes were sutured using absorbable suture to an intact peritoneum in 20 New Zealand white rabbits. The study groups included: polypropylene (PP) [Marlex; C.R. Bard Inc, Cranston, NJ], expanded polytetrafluoroethylene (ePTFE) [DualMesh; WL Gore, Flagstaff, AZ], ePTFE and PP (ePTFE/PP) [Composix, C.R. Bard Inc], reduced weight PP and oxidized regenerated cellulose (rPP/C) [Proceed; Ethicon, Inc, Somerville, NJ]. The meshes were explanted after one year. Adhesions were scored as a percentage of explanted biomaterials' affected surface area. Prosthetic shrinkage was calculated. The strength of incorporation and mesh compliance were evaluated using differential variable reluctance transducers. Mesh ingrowth was measured as the load necessary to distract the mesh/tissue complex. Mesh compliance was calculated as the change in linear displacement of the sensors due to applied load. The groups were compared using Student's t-test and Fisher's exact test. RESULTS: ePTFE had significantly less adhesions (0%) than both ePTFE/PP (40%) and PP (80%) groups (P < 0.001). The mean area of adhesions for the rPP/C (10%) and the ePTFE/PP (14%) groups was less than that for the PP group (40%) (P = 0.02). Prosthetic shrinkage was greatest in the ePTFE (32%) group than in any other group (P = 0.001). There were no differences in mesh incorporation between the groups. At explantation, mesh compliance in the ePTFE group was superior to other meshes (P < 0.0001). The rPP/C mesh induced the smallest change in the compliance of the tissue adjacent to the mesh (P = 0.0001). CONCLUSIONS: Prosthetic materials demonstrate a wide variety of characteristics. Although exposed PP formed the most adhesions, up to 40% of the other PP-based meshes formed adhesions despite protective barriers. The ePTFE mesh did not induce adhesions and was the most compliant, however, this prosthetic's contraction was greatest. Reduced weight polypropylene (rPP/C) mesh induced the smallest change in the adjacent tissue pliability/compliance. Understanding of the long-term effects of various prosthetic materials is important to ensure an adequate hernia repair while minimizing postoperative morbidity and patient discomfort.     

A meta-analysis comparing tacker mesh fixation with suture mesh fixation in laparoscopic incisional and ventral hernia repair

Objective

To systematically compare the tacker mesh fixation (TMF) with the suture mesh fixation (SMF) in laparoscopic incisional and ventral hernia (LIVH) repair.

Methods

Trials evaluating the TMF with the SMF in LIVH repair were analysed using the statistical tool RevMan^®. Combined dichotomous and continuous data were expressed as odds ratio (OR) and mean difference (MD), respectively.

Results

Four trials (2 randomised and 2 non-randomised) encompassing 207 patients undergoing LIVH repair with TMF versus SMF were retrieved from the standard electronic databases and analysed systematically. Ninety-nine patients underwent TMF and 108 patients underwent SMF in LIVH repair. There was no statistically significant heterogeneity (p = 0.27)] among trials. In the fixed-effects model, LIVH repair with TMF was associated with shorter operation time (MD, ?23.65; 95 % CI, ?31.06, ?16.25; z = 6.26; p < 0.00001). Four- to six-week postoperative pain score was significantly lower (MD, ?0.69; 95 % CI, ?1.16, ?0.23; z = 2.92; p < 0.004) following TMF. Peri-operative complications (p = 0.65), length of hospital stay (p = 1) and risk of hernia recurrence (OR, 1.54; 95 % CI, 0.38, 6.27; z = 0.61; p = 0.54) following TMF and SMF were statistically not different.

Conclusion

TMF in LIVH repair is associated with shorter operative time and lesser postoperative pain. TMF is comparable with SMF in terms of peri-operative complications, length of hospital stay and hernia recurrence. Therefore, TMF may be used in LIVH repair. However, further randomised trials recruiting higher number of patients are required to validate these findings.     

Evaluation of a knitted polytetrafluoroethylene mesh placed intraperitoneally in a New Zealand white rabbit model

Background

The intraperitoneal application of surgical mesh remains a controversial issue because of possible complications, especially adhesion and fistula formation. This study aimed to assess the potential of a knitted polytetrafluoroethylene (PTFE) mesh for intraabdominal implantation.

Methods

Twenty-eight 5?×?5?cm samples of knitted macroporous PTFE mesh and light-weight polypropylene mesh (LW-PP) were implanted intraperitoneally in 14 New Zealand white rabbits in a randomized manner and fixed using eight polypropylene stitches. After 90?days, the adhesion formation, adhesion score, shrinkage, strength of fixation to the abdominal wall, and histologic biocompatibility were assessed.

Results

No intraoperative or anesthesia-related complications or mesh infection were recorded. The average area covered by adhesions was 4.7?±?7.2% for the PTFE and 36.4?±?36.1% for the LW-PP. The median adhesion score was 0 for the PTFE and 8 for the LW-PP. Shrinkage was 36.9?±?12.9% for the PTFE mesh and 12.6?±?8.72% for the LW-PP. The mesh-to-abdominal wall fixation strength was almost the same for both materials (PTFE 3.6?±?1.9 vs. LW-PP 3.6?±?2.9). The inflammatory cell count was almost the same for the two groups, with no statistically significant difference. The width of the inner granuloma was equal (PTFE 10.5?±?0.9 vs. LW-PP 11.1?±?0.9). The outer granuloma was reduced significantly in the PTFE group (PTFE 23.0?±?2.1 vs. LW-PP 33.6?±?7.9). One of the animals in the PTFE group died on postoperative day 12 because of ileus. The reason was an adhesion of the small intestine to the polypropylene fixation stitch, which caused small intestine strangulation.

Conclusions

The knitted PTFE mesh induces fewer intraperitoneal adhesions of lower density than the light-weight polypropylene mesh. The strength of the knitted PTFE mesh fixation to the abdominal wall is comparable with that of the light-weight polypropylene mesh, but the shrinkage is greater. The biocompatibility of the knitted PTFE mesh is comparable with that of the light-weight polypropylene implant.     

Osseointegration of polyethylene implants coated with titanium and biomimetically or electrochemically deposited hydroxyapatite in a rabbit model

Purpose

The aim of this study was to evaluate the osseointegration of a new coating directly deposited on PE at room temperature.

Methods

Thirty-six (36) male New Zealand rabbits were randomly assigned to receive one out of three types of implants: two tested implants, i.e. PE implant coated with TiPVD and biomimetic HA (biomimetic), PE implant coated with TiPVD and electrolytic HA (electrolytic), and positive control made of massive microrough titanium coated with plasma sprayed HA (TiHAPS). Osseointegration was evaluated by histomorphometry (bone tissue in contact [BIC]), mineralized bone area [MBA]) and mechanical testing (push-out test, interfacial shear strength [ISS]) at six and 12 weeks in the distal femurs.

Results

For BIC there were no differences between the groups at six (p = 0.98) and 12 weeks (p = 0.13). For MBA, no statistically significant difference was measured between groups at six (p = 0.52) and 12 weeks (p = 0.57). At six weeks, interfacial shear strength (ISS) was significantly higher (p = 0.01) for TiHAPs implants compared to biomimetic and electrolytic implants. This difference was not significant at 12 weeks (p = 0.92).

Conclusion

The osseointegration of biomimetic and electrolytic implants was equivalent to a positive control at 12 weeks.