Repair of bone defect with vascularized tissue engineered bone graft seeded with mesenchymal stem cells in rabbits

This study evaluated the results of repair of the radius defect with a vascularized tissue engineered bone graft composed by implanting mesenchymal stem cells (MSCs) and a vascular bundle into the xenogeneic deproteinized cancellous bone (XDCB) scaffold in a rabbit model. Sixty-four rabbits were used in the study. Among them, four rabbits were used as the MSCs donor. Other 57 rabbits were divided into five groups. In group one (n = 9), a 1.5 cm bone defect was created with no repair. In group two (n = 12), the bone defect was repaired by a XDCB graft alone. In group three (n = 12), the defect was repaired by a XDCB graft that included a vascular bundle. In group four (n = 12), the defect was repaired by a XDCB graft seeded with MSCs. In group five (n = 12), the defect was repaired by a XDCB graft including a vascular bundle and MSCs implantation. The rest three rabbits were used as the normal control for the biomechanical test. The results of X-ray and histology at postoperative intervals (4, 8, and 12 weeks) and biomechanical examinations at 12 weeks showed that combining MSCs and a vascular bundle implantation resulted in promoting vascularization and osteogenesis in the XDCB graft, and improving new bone formation and mechanical property in repair of radius defect with this tissue engineered bone graft. These findings suggested that the vascularized tissue engineered bone graft may be a valuable alternative for repair of large bone defect and deserves further investigations.     

Periosteal neochondrogenesis for biologically resurfacing joints: its cellular origin

The purpose of this study was to determine if the hyaline-like cartilage produced in major full-thickness defects of a joint surface, treated by a free periosteal graft and subjected to continuous passive motion (CPM), originated exclusively from the progenitor cells of the cambium of the graft. Free periosteal grafts were raised from the tibia of both hind legs of eight male New Zealand rabbits and transplanted into full-thickness defects across the entire width of the patellar groove of 15 female rabbits. Postoperatively, CPM was instituted and the animals were sacrificed after 3 weeks. Cells from the regenerated tissue were grown from tissue explants and their karyotypes determined. In 33% of the rabbits, all cells contained a Y (male) chromosome, indicating that regenerated tissue originated exclusively from the progenitor cell of the periosteal graft. Karyotypes of the cells from the other 67% were mosaics (both female and male); thus, their cellular origin was from both the periosteal allograft and the pluripotential mesenchymal cells in the subchondral tissues.     

Prefabrication of periosteal graft alone or with oxidised cellulose: an experimental study

The purpose of this study was to evaluate the feasibility of prefabrication of periosteal grafts, alone or with oxidised cellulose (surgicel), which was an osteoinductive material using femoral vasculature. Fifteen white New Zealand rabbits were used in both femoral regions (30 grafts), and randomly divided into three groups including five rabbits (10 grafts): the control group, the periosteal graft group, and the periosteal graft+surgicel group. A periosteal graft, 30 x 40 mm in size, was obtained from the calvarium of each rabbit. The periosteal graft taken was divided into two equal parts, 20 x 30 mm. All these periosteal grafts were sutured in the shape of tube. In all rabbits, femoral vasculature and periosteal tube was Included in a silicone tube. Additionally, in the control group, femoral vasculature was cut above and below the silicone tube, whereas in the periosteal graft+surgicel group, surgicel was added to the periosteal graft. The results were evaluated macroscopically and histopathologically in the second (two rabbits for each group - 4 grafts) and fourth week (3 rabbits for each group - 6 grafts). In the second week, In all three groups, while no osteoid tissue that indicated osteogenesis developed, it was seen that inflammation and increased vascularity occurred. Surgicel was observed to be absorbed in the periosteal graft+surgicel group. In the fourth week, fibrotic tissue was developed whereas inflammatory tissue disappeared; any osteoid tissue or lamellar bone was not accompanied in all three groups. In conclusion, we do not believe that periosteum was able to survive as a graft, and we found that neovascularization occurred too slowly to preserve the bone forming qualities of the periosteum. We suggested that it could not be prefabricated, being taken away from its donor site although surgicel was used as a stimulating material.     

Comparison of AlloDerm, fat, fascia, cartilage, and dermal grafts in rabbits

OBJECTIVE: To compare various graft materials in the rabbit model, including autologous cartilage, dermal tissue, fat, and AlloDerm (a cadaver-derived material). METHODS: Twenty-five New Zealand white rabbits were used. Equally sized autogenous (fat, fascia, cartilage, and dermal) grafts and AlloDerm were implanted into subcutaneous dorsal pockets on the rabbits. Animals were killed 1, 2, 3, and 4 months after surgery. The grafts were examined microscopically for thickness, resorption, fibrosis, neovascularization, inflammation, eosinophilia, and the presence of multinucleated giant cells or microcysts. RESULTS: The cartilage grafts revealed excellent viability with no resorption. The fascial grafts showed negligible volume loss. The dermal grafts developed epidermoid cysts. The AlloDerm grafts demonstrated graft thickening at 1 month and total resorption at 3 and 4 months. The fat grafts demonstrated 30% to 60% partial resorption. CONCLUSIONS: The major disadvantage of using an autogenous fat graft was partial resorption, whereas cyst formation was observed with dermal grafts. AlloDerm caused tissue reaction and resorption. The best graft material was cartilage, with a low absorption rate, good biocompatibility, and minimal tissue reaction or fibrosis, followed by fascia, with a minimal shrinkage capacity and tissue reaction.     

Chondrogenesis in Repair of Articular Cartilage Defects by Free Periosteal Grafts in Rabbits

The origin of the cartilaginous tissue in articular defects after periosteal grafting was studied histologically in 6-month-old rabbits. The grafts were taken from the tibia and transplanted to artificial defects in the femoral articular cartilage. An isolating Nucleopore filter^®, hindering the penetration of cells, was placed between the graft and the cancellous bone, in order to trace the origin of the proliferating cells. The histological results revealed that the cartilage tissue which proliferated in the defect originated from the periosteal graft and not from the subchondral bone. The effect of the depth of the defect was studied by making a superficial and deep part in the defect. Cartilage tissue was found in both parts of the defect, though there was less in the more superficial defect.     

骨髓基质成骨细胞复合支架材料构建组织工程性肌骨瓣的实验研究

目的探索用羟基磷灰石/磷酸三钙(HA/TCP)的支架材料与成骨细胞复合构成组织工程性肌骨瓣修复骨缺损的能力。方法自2004年12月至2005年5月,于新西兰大耳白兔髂后上棘抽取骨髓基质干细胞并诱导分化为成骨细胞,然后与HA/TCP结合,共培养2周,通过相差显微镜、扫描电镜观察体外细胞生长情况,最后将复合物埋入兔的背阔肌下构成组织工程性肌骨瓣。术后6周进行大体解剖观察,HE染色,研究组织工程性肌骨瓣的生长情况。结果扫描电镜显示支架材料表面和孔隙内均有成骨细胞生长,有良好的增殖活动性和稳定细胞表型,材料中心区未见细胞生长,植入体内6周后取材见内植物有新骨形成,多位于内植物表面,可见成骨细胞、骨细胞、髓腔样结构、板层样骨基质等正常骨组织结构。结论骨髓来源的成骨细胞可用作骨组织工程的种子细胞,此种组织工程性肌骨瓣生长良好,可成功构建组织工程化骨。     

Vascularized tendon grafting in the rabbit.

Using a conventional free tendon graft, adhesion formation, with a consequent loss of gliding ability, occurs if the surrounding soft tissue is heavily scarred. An animal experiment was conducted, to evaluate whether a free vascularized tendon graft provides a better gliding surface, with minimal adhesion formation. In order to scar the gliding floor, the lateral aspect of the legs of 40 adult rabbits, including the peroneus tendon and its surrounding soft tissue, was exposed to liquid nitrogen. Two weeks after this induction of frostbite, all the rabbits were randomly divided into two groups: a vascularized tendon graft group and a free tendon graft group. Histologic examination revealed less adhesion of the tendon to the surrounding soft tissues in the vascularized tendon graft group. The tendon pull-out test demonstrated that less pull-out weight was required for vascularized tendons. A microangiographic study disclosed better circulation through the tendon graft and the surrounding soft tissues in the vascularized tendons. These results suggest that, even if scarring is heavy, the free vascularized tendon graft is less likely to adhere to the surrounding soft tissue than the conventional free tendon graft and, consequently, it provides a better gliding surface.     

Load-bearing increases new bone formation in impacted and morselized allografts

The effects of mechanical loading on the incorporation of morselized impacted grafts were addressed in this study. Twelve skeletally mature rabbits were surgically treated. Six rabbits received a proximal tibial joint replacement with a tibial tray and a load-bearing 25-mm long stem. The tibia was packed with fresh frozen, morselized, cancellous rabbit bone. No cement was used. In six other rabbits only the stem was inserted, without a tibial tray, leaving the stem and the likewise impacted bone graft mechanically unloaded. The rabbits were euthanized after 6 weeks, and the tibias were sectioned and analyzed by histomorphometric examination. In the loaded specimens the graft was resorbed and replaced by new bone (30% of area of interest) to a larger extent than in the unloaded specimens. Mechanical loading of an impacted, morselized graft surrounding a conical uncemented stem, increased the amount of new bone that replaced the graft. The ability of morselized impacted grafts to allow mechanical stimulation of ingrown tissue appears to be a principal cause for the success of this grafting procedure.     

Allograft of cultured chondrocytes into articular cartilage defects in rabbits--experimental study of the repair of articular cartilage injuries

Articular cartilage defects were created by dill holes, 2 mm wide and 3 mm deep, through the articular cartilage into the subchondral bone in the patellar groove of the femur in mature rabbits. The defects received graft of cultured chondrocytes and the matrix obtained from the primary culture of chondrocytes isolated from the articular cartilage or auricular cartilage in immature rabbits. The isolated cells were cultured for 10 to 14 days. For graft, the cultured chondrocytes together with the matrix were detached from the culture chamber using rubber policemen and centrifuged. The repair of the grafted defects or defects without graft (control) was histologically studied 2 to 12 weeks after operation. The defects without the graft were progressively filled with fibrous tissue containing spindle shaped cells, fibers perpendicular to the surface, and matrix showing weak metachromasia with toluidin blue at 8 weeks. The defects received articular cartilage cell graft were occupied by new cartilage tissue consisting colonylike crumps of chondrocytes 2 weeks after operation. The crumps showed strong metachromasia with toluidin blue and strong stainability for safranin-O. By 4-8 weeks, the defects were filled with homogeneous cartilage. At 12 weeks, arrangement of the chondrocytes of the superficial layer of the new cartilage became columnar as seen in the normal articular cartilage. The defects received elastic cartilage cell graft were filled by reformed cartilage with chondrocytes surrounded by elastic fibers 2-12 weeks after operation. The results indicate that allograft of cultured chondrocytes with matrix into the articular cartilage defects accerated the repair process of the defects by formation of the new cartilage derived from the grafted chondrocytes.     

骨髓基质细胞移植修复半月板无血运区损伤的实验研究

目的比较自体与同种异体骨髓基质细胞移植对半月板无血运区损伤修复的影响。方法 40只成年新西兰大白兔随机平均分为 A、 B两组。 A组兔的骨髓基质细胞 (MSC)经体外培养后与纤维蛋白凝胶 (FG)混合,自体移植于其一侧的膝关节半月板缺损区,即 FG＋自体 MSC（自体移植组）;另一侧单纯植入 FG(FG植入组 )。于 B组兔的一侧膝关节半月板缺损区移植 FG＋同种异体 MSC(异体移植组 ),另一侧缺损不予修复 (空白对照组 )。分别于术后第 1、 2、 3个月取材,观察半月板损伤部位的组织形态学变化。结果 (1)自体移植组 :术后 1个月缺损区可见纤维组织,内有大量成纤维细胞;术后 2个月见大量软骨细胞并有胶原纤维形成;术后 3个月损伤区呈纤维软骨愈合。 (2)空白对照组 :术后 1～ 3个月缺损区始终未愈合。 (3)单纯 FG植入组 :术后 1～ 3个月缺损区可见纤维组织,内有少量成纤维细胞,没有软骨细胞生长,呈瘢痕样愈合。 (4)同种异体移植组 :与自体移植组所见大致相同,但有 3侧缺损区可见大量淋巴细胞浸润,胶原纤维少。结论骨髓基质细胞移植可促进半月板无血运区损伤的愈合,同种异体骨髓基质细胞移植修复半月板无血运区损伤发生免疫排斥反应的机率较低。     

钻孔复合人工骨体内植入成骨的实验研究

目的探索符合临床需要的复合人工骨移植材料。方法以磷酸三钙＋多孔羟基磷灰石 (TCP＋ HA)为载体 ,分为钻孔、未钻孔及空白对照三组。自成年新西兰兔股骨转子部取得骨髓基质细胞进行传代培养,所得骨髓基质细胞再与钙磷陶瓷载体复合培养制成复合人工骨。然后植入兔背部肌肉内,分别于手术后第 2、 4、 8、 12周取材。利用组织学和电子显微镜等方法观察细胞在载体内的生长、复合人工骨植入肌肉内的成骨等情况,以及载体钻孔对细胞长入和成骨的影响。结果电子显微镜观察显示,传代的骨髓基质细胞与载体共同培养生长良好,并可长入钻孔载体内部。大体标本可见,复合人工骨植入后,人工骨与周围肌肉连接,无包膜形成。组织学观察显示,术后第 2周组织和血管长入;术后第 4～ 8周有少量骨形成;术后第 12周板层骨形成。三组均无淋巴细胞浸润。与未钻孔者比较,钻孔人工骨的细胞、组织和血管向中心部位生长速度快,中心部位成骨多且更均匀。结论磷酸三钙＋多孔羟基磷灰石载体具有良好的生物相容性及骨传导性;骨髓基质细胞具有成骨能力;载体钻孔有利于增加新骨形成的速度和数量,使成骨更为均匀。     

小肠黏膜下层修复尿道的实验研究

目的探讨小肠黏膜下层(small intestinal submucosa,SIS)在尿道修复重建中的应用价值.方法 24只日本雄性大耳白兔,随机分为A、B、C及D组(n=6).A、B组切除前尿道2.0 cm,A组,用管状SIS修复尿道缺损;B组将其断端与周围组织直接缝合作为对照.C、D组仅切除2.0 cm尿道前壁,保留一半尿道壁为底板,C组用片状SIS修复尿道缺损;D组将其残端与周围组织直接缝合作为对照.均于修复后6、12周行组织学观察;12周行尿道膀胱造影及尿动力学检查.结果术后6周,A、C组修复的尿道有单层上皮细胞覆盖,基层组织中可见SIS的微小碎片包裹,出现不规则紊乱的平滑肌细胞生长,A组较C组的炎性反应重,有白细胞及淋巴细胞浸润,C组出现新生血管.术后12周,C组的上皮组织及基层下组织与D组无明显差别,平滑肌排列规则,血管数目进一步增多,炎性反应消失,未见SIS组织;A组中仍可见少数SIS的微小碎片;B组1只、D组2只尿道自行修复,余可见尿道闭塞,大量结缔组织生长,炎性细胞浸润,无正常上皮结构.术后12周尿道膀胱造影,A、C组可见尿道完整、光滑,无尿液外渗、尿道憩室等形成;尿动力学检查示A、C组的膀胱容量、最大尿道压分别与术前比较,差异无统计学意义(P＞0.05),而B、D组不能置入测压管检测.结论 SIS可作为兔尿道修复重建的良好支架材料,片状SIS修复优于管状SIS修复.     

Local treatment of Dacron patch graft contaminated with Staphylococcus aureus with antibiotic-releasing porous apatite ceramic: an experimental study in the rabbit

OBJECTIVE: The purpose of this study was to investigate whether or not infection of prosthetic vascular graft could be prevented with the placement of antibiotic-loaded porous apatite ceramic on the graft with bacterial contamination. METHODS: Teicoplanin as an antibiotic was loaded into a beta-tricalcium phosphate (TCP) block of porous apatite ceramic. The activity of teicoplanin released from teicoplanin-loaded TCP was examined for 40 days at 2-day intervals. In an in vivo study, the graft was patched in the abdominal aorta of a rabbit. Two different doses of Staphylococcus aureus were applied (n = 13). Teicoplanin-loaded TCP was placed around the graft infected with S aureus (n = 6). The graft, the tissue around it, and the arterial blood were collected and cultivated 4 weeks after operation. RESULTS: The activity of teicoplanin in the replaced saline solution was maintained for at least 40 days. Because graft infection was established in all rabbits with a dose of 2 x 10(7) colony forming units, this dose was used as the dose of S aureus in this study. Fifty-seven percent of the subjects died from the infection. When teicoplanin-loaded TCP was placed around the graft contaminated with S aureus, no rabbits died. Bacterial cultures of the graft and of tissues around it were negative in all rabbits killed 4 weeks after operation. This infection was prevented with teicoplanin-loaded TCP in all rabbits. CONCLUSION: Teicoplanin-loaded TCP may be useful in avoiding Dacron graft infection with S aureus in rabbits.     

The repair of major osteochondral defects in joint surfaces by neochondrogenesis with autogenous osteoperiosteal grafts stimulated by continuous passive motion. An experimental investigation in the rabbit

The purpose of this investigation was to determine the effects of continuous passive motion (CPM) on the chondrogenic potential of autogenous osteoperiosteal grafts to repair major osteochondral defects. A 3.5-mm-wide circular full-thickness defect was drilled in one medial femoral condyle of 55 adolescent New Zealand rabbits. A graft of periosteum from the proximal tibia was wrapped around a disc of bone from the same area (cambium layer of the periosteum facing outward), then press-fitted into the defect. The rabbits were treated by either immobilization (Imm) or intermittent active motion (IAM) for five weeks, or by continuous passive motion (CPM) for two weeks followed by IAM for three weeks. A control group (no osteoperiosteal graft in the defect) was also treated by CPM for two weeks and IAM for three weeks. At five weeks, hyaline cartilage was the predominant tissue in only 10% of the defects in the Imm, IAM, and control groups, compared with 70% in the CPM group (p less than .025). Bonding of the newly formed tissue to the adjacent cartilage was significantly better in the CPM group.     

Scleral reinforcement in rabbits using synthetic graft materials

Because of disappointing results using homologous collagen for scleral reinforcement in the treatment of pathologic myopia in humans, we undertook a series of experiments in rabbits to test the mechanical properties and long-term biocompatibility of three different synthetic graft materials. Grafts made from two of these materials, Gore-Tex Soft Tissue Patch (expanded polytetrafluoroethylene) and Miragel (poly[methyl acrylate-co-hydroxy-ethyl acrylate]), were easy to position about the globe. Both materials, however, were resistant to invasion by fibrovascular tissue. The third material, woven Dacron (polyethylene terephthalate), though more difficult to position, permitted extensive invasion of fibrovascular tissue, which made all parts of the graft firmly adherent to the globe. Our results indicate the long-term compatibility of all three of these materials when used as periscleral grafts in rabbits. However, our results also suggest that a woven material such as commercially available Dacron is a more suitable graft material for scleral reinforcement in humans than collagen, Miragel, or Gore-Tex.     

Persistence of allogeneic cells in graft and host tissues after small bowel transplantation.

Small bowel transplantation is associated with a significant risk of graft versus host disease owing to the large amount of organized lymphoid tissue within the graft. This study assessed whether graft lymphoid cells could persist in the long term following fully allogeneic small bowel transplantation when graft rejection was prevented by cyclosporin immunosuppression. Transplantation was carried out between PVG and DA strains of rat. Cyclosporin (15 mg/kg) was given daily from transplantation, and groups of animals were studied at 28 and 56 days after grafting. The proportions of donor- and recipient-derived cells in the graft and in the host gut and lymphoid tissues were assessed using immunohistochemical tissue staining and monoclonal antibodies specific for cells expressing class I antigens from the two strains of rat. Results demonstrated a persisting population of graft-derived T cells which were capable of migration to the host. Therefore, there may be a long-term risk of graft versus host disease after small bowel transplantation under cyclosporin immunosuppression.     

The chondrogenic potential of free autogenous periosteal grafts for biological resurfacing of major full-thickness defects in joint surfaces under the influence of continuous passive motion. An experimental investigation in the rabbit

A rectangular graft of autogenous tibial periosteum was sutured (with its cambium layer facing into the joint) onto the base of a five by ten-millimeter full-thickness defect in the patellar groove of each of 143 adolescent and adult rabbits. The rabbits were managed postoperatively by either immobilization, intermittent active motion, continuous passive motion for two weeks, or continuous passive motion for four weeks. When the animals were killed four weeks postoperatively, the contour of the patellar groove had been restored in all of the rabbits in the group that had had four weeks of continuous passive motion, and the newly formed tissue in all of the defects in this group had the gross, histological, and histochemical appearance of smooth, intact hyaline articular cartilage. Histologically, the nature of the tissue that had formed, as well as its surface regularity, structural integrity, and bonding to the adjacent cartilage, were significantly better in the group that had had four weeks of continuous passive motion than in any of the other groups. The results were significantly worse when the orientation of the periosteal graft was reversed (that is, when it had been sutured into the defect with the cambium layer of the graft facing the subchondral bone rather than into the joint) or when no periosteal graft was used. Biochemical analyses revealed that, in the group that had had four weeks of continuous passive motion, the total hexosamine content, the levels of chondroitin sulphate and keratan sulphate, and the ratio of galactosamine to glucosamine were all comparable with the values for normal articular cartilage. In contrast, in the groups that were treated by immobilization, intermittent active motion, or two weeks of continuous passive motion, as well as in the adult rabbits, the content of the first three of these substances was significantly less than normal. In the groups that were treated by immobilization, intermittent active motion, or two weeks of continuous passive motion, 32 to 47 per cent of the total collagen was type II, while in the group that had had four weeks of continuous passive motion, 93 per cent of the total collagen was type II. These results demonstrate that, under the influence of continuous passive motion, free autogenous periosteal grafts can repair a large full-thickness defect in a joint surface by producing tissue that resembles articular cartilage grossly, histologically, and biochemically, and that contains predominantly type-II collagen.     

Histologic evaluation of human cadaveric fascia lata in a rabbit vagina model

The purpose of this study was to evaluate the histologic response of human cadaveric fascia lata after vaginal implantation. Freeze-dried, gamma-irradiated cadaveric fascia lata from three lots was implanted between the rectovaginal membrane and vaginal epithelium in New Zealand white rabbits. Rabbits were killed at 2, 4, 8, and 12 weeks after implantation. At necropsy, gross findings were described and specimens for routine cultures were taken. Histologic evaluation determined graft integrity, neovascularization, inflammatory response, and host tissue incorporation. Nine rabbits were available for histologic analysis and 14 for gross and microbiologic analysis. Vaginal erosions occurred with three grafts. The remainder were adherent to the surrounding tissues. Erosion was associated with bacterial colonization of the graft. Autolysis of one graft occurred at 4 weeks. Over time, the inflammatory response decreased and neovascularization increased; by 12 weeks, the graft collagen was replaced by host collagen. Cadaveric fascia lata serves as scaffolding for host tissue incorporation with replacement by host collagen.Oral/Poster presentation at the Annual Meeting of the Society of Gynecologic Surgeons, Orlando, Florida, March 2001.     

Evaluation of a novel propylene oxide-treated collagen material as a dural substitute

OBJECT: The authors evaluated a new non-cross-linked, propylene oxide-treated, acellular collagen matrix for use as a dural substitute in rabbits. They then compared this material to a commonly used dural substitute as well as to native dura mater used during primary closure. METHODS: Forty-six rabbits were randomly assigned to eight groups of five or six rabbits each. These groups differed according to the type of closure material that was used during surgery (native dura, control dural substitute, or experimental dural substitute) and the duration of convalescence. At the end of the experiment, the tightness of the duraplasty was assessed in each live rabbit by continuous infusion of fluid into the cistema magna until leakage was detected. The animals were killed and each specimen was sectioned and studied histologically. The authors found that the experimental dural substitute was safe in animals for this application, that it held sutures well, and that a watertight closure was usually achieved. There were fewer adhesions between the experimental material and neural tissue was less likely to adhere to the cranium than the control graft. Histological examination showed that the experimental material had slightly more spindle cells and vascularity than the control graft. CONCLUSIONS: The experimental graft material has several features that make it an attractive candidate for use as a dural substitute.     

Comparison of Marlex mesh and microporous teflon sheets when used for hernia repair in the experimental animal.

A new prosthetic material, microporous expanded Teflon (PTFE) was compared with Marlex mesh in the experimental animal. Triangular pieces of each material were placed beneath the transversalis fascia in the right and left groins of seven white New Zealand rabbits (mean weight, 8 kg). The animals were sacrificed are two week intervals. PTFE was found to retain its position and shape without local or peritoneal reaction. By contrast, Marlex mesh showed marked inflammatory reaction and scarring with complete distortion of the graft. Microscopically, PTFE was completely invaded by fibroblast at eight weeks, with flat orientation of graft to the fibrous tissue forming a "neofascia". In contrast, Marlex mesh lacked fibroblastic incorporation of the graft with marked scarring and distortion. These findings suggest that PTFE could be a useful fascial buttress in inguinal hernia repair where Marlex mesh is now used.