Polypropylene Prosthesis Research Articles

Hernia inguinocrural: estudio multicéntrico sobre técnicas quirúrgicas

The present study was performed by the Spanish Association of surgeons through its abdominal wall and sutures section. The aim was to determine the current situation of inguinofemoral hernias in Spain and was based on an anonymous multicenter study with the participation of various national hospitals.Fifty general surgery departments in distinct surgical centers throughout Spain responded to an anonymous survey in 2000. The survey gathered data on anesthetic features, surgical techniques and complications in the treatment of inguinofemoral hernias.Sixty-six percent of hospital centers had a specific abdominal wall unit and 24% performed laparoscopic hernia surgery. Prosthetic techniques (especially Lichtenstein) were the most frequently used in the treatment of primary inguinal hernia (72%) and recurrent hernia (100%). The most frequently used prosthetic material was polypropylene mesh (76%). Only 28% of the departments surveyed performed anatomic techniques in the repair of primary inguinal hernia (Shouldice and Bassini). The most frequent treatment for femoral hernia was the Lichtenstein "plug" (78%). Sixty-eight percent of the centers surveyed performed regional anesthesia, 18% used general anesthesia and only 14% used local anesthesia with sedation. Severe complications were found in 20% of departments. Clinical postoperative follow-up was performed in 96% of the centers and telephone follow-up was used in 4%. The recurrence rate was 1.2% for primary inguinal hernia, 2.7% for recurrent inguinal hernia and 0.3% for femoral hernia.In Spain the most commonly used surgical technique in the treatment of inguinal hernia is Lichtenstein hernioplasty under spinal anesthesia and with polypropylene prosthesis. The Lichtenstein plug is the most commonly used technique in the treatment of femoral hernia.

Composite prostheses used to repair abdominal wall defects: Physical or chemical adhesion barriers?

In a composite prosthesis, the component placed at the peritoneal interface takes the form of a physical or chemical barrier. In this experimental study performed on the white New Zealand rabbit, several composites were examined to establish the effectiveness of these barriers at impeding adhesion formation. The biomaterials tested were two polypropylene prostheses (PP) with the physical barriers of expanded polytetrafluoroethylene or polyurethane (PP + ePTFE and PP + PU) and two prostheses (one polyester and the other PP) with the absorbable chemical barriers of polyethylene glycol/glycerol and hyaluronate, respectively (PO + gl and PP + hy). The composites were used to repair 7 x 5 cm defects created in the abdominal wall of the animals by placing the implant in contact with the visceral peritoneum and the subcutaneous tissue and fixing it to recipient tissue by 4/0 polypropylene running suture. Fourteen days after surgery the animals were sacrificed and specimens were taken for light microscopy and scanning electron microscopy. Adhesions developing at the prosthesis/visceral peritoneal interface were quantified. All the prostheses induced optimal mesothelialization. Composites with physical barriers behaved similarly in terms of provoking adhesions. However, the prostheses with chemical barriers differed in their effectiveness at preventing adhesions. Overall, the best results were obtained with the PP + PU composite.

Tumor desmóide da parede abdominal durante a gravidez: relato de caso

Tumores desmóides são neoplasias do tecido conjuntivo, caracterizadas por apresentarem crescimento exclusivamente loco-regional, recorrência freqüente e mínimo potencial metastático. Acometem principalmente portadores de polipose adenomatosa familial dos cólons, sendo sua ocorrência isolada extremamente rara. São mais freqüentes nas mulheres em idade reprodutiva e durante a gravidez. Descreve-se um caso de tumor desmóide de grandes proporções, localizado na parede abdominal, que surgiu a partir da 17ª semana em gestante sem antecedentes de polipose adenomatosa familial. A neoplasia foi totalmente extirpada utilizando-se prótese de polipropileno para reconstituição da parede abdominal. Atualmente a doente encontra-se bem, um ano após a cirurgia, em uso de antiinflamatório não hormonal para prevenção de recidivas.

Tissue integration and biomechanical behaviour of contaminated experimental polypropylene and expanded polytetrafluoroethylene implants.

Infection is one of the most devastating complications following implantation of a prosthetic material. The aim of this study was to compare the behaviour of two biomaterials contaminated with Staphylococcus aureus or Staphylococcus epidermidis, used to repair abdominal wall defects. Defects (7 x 5 cm) were created in the anterior abdominal wall of 60 white New Zealand rabbits and repaired using polypropylene or expanded polytetrafluoroethylene (ePTFE) prostheses. The site of repair had been previously inoculated with 10(6) colony-forming units/ml S. aureus or S. epidermidis. Seven and 30 days after implantation, prosthetic specimens were examined by light and scanning electron microscopy, and immunohistochemical and biomechanical analysis. No significant differences with respect to controls were observed in the S. epidermidis groups. Two animals inoculated with S. aureus died. S. aureus induced the appearance of denuded areas exposing the filaments in the polypropylene prostheses, whereas the ePTFE prostheses showed zones of erosion, disorganized tissue, haemorrhage and necrosis. The biomechanical strength of the contaminated implants was unaltered. Integration within host tissue was affected in the setting of S. aureus infection but the tensile strength of contaminated prostheses was not significantly reduced.

Efeitos da prótese de polipropileno colocada por inguinotomia no espaço pré-peritoneal, em cães: avaliação laparoscópica e microscópica

OBJETIVO: Observar os efeitos produzidos pela prótese de polipropileno no espaço pré-peritoneal. MÉTODOS: 10 cães (n=10), adultos e sem raça definida, foram submetidos a inguinotomia bilateral, nas quais se colocou uma prótese em um dos lados. Na região contralateral, o procedimento foi o mesmo, sem a colocação da prótese, servindo como controle. Após 30 dias os animais foram submetidos a uma videolaparoscopia e foi realizada a avaliação macroscópica por via intraperitoneal, além do registro das alterações histológicas das duas regiões inguinais. RESULTADOS: Três (03) animais apresentaram aderências epiplóicas no local de implantação da prótese de polipropileno. Nenhum animal apresentou aderência no lado B (sem prótese). As alterações microscópicas no lado A (com prótese) caracterizaram-se pela proliferação de tecido conjuntivo fibroso denso, além da escassa presença de células gigantes multinucleadas, comprovando uma reação inflamatória de leve intensidade. CONCLUSÃO: A prótese de polipropileno induz a formação de aderências em 30% dos animais, quando colocada no espaço pré-peritoneal em cães.

Comparison of Tissue Integration between Polyester and Polypropylene Prostheses in the Preperitoneal Space

Tissue integration and implant characteristics of various biomaterials commonly used for inguinal hernia repair have not been studied extensively. The aim of this study is to compare behavior and tissue response between two new polyester prostheses and a commonly used polypropylene (PP) mesh. The polyester prostheses utilized were polyester flat (PF) and polyester soft three-dimensional (PS); the PP mesh utilized was Marlex®. Eight randomly assigned 4 x 4-cm2 pieces of two different meshes were fixed in the preperitoneal space with a centrally placed single suture. Gross evaluation included shrinkage and stiffness. Histological evaluation included amount of fibrous and fat encapsulation, connective tissue, foreign-body reaction, neovascularization, hemorrhage, necrosis, and exudate. Evaluations were graded on a zero to four scale. The area and the area ratio were measured using a calibrated micrometer. PP mesh resulted in more fibrous encapsulation and stiffness than PF and PS prostheses. PP also resulted in less connective tissue formation and foreign-body reaction than PF and PS prostheses. There was no difference in fat encapsulation, necrosis, hemorrhage, or exudate between prostheses. Both polyester prostheses (PF and PS) have better tissue integration than the PP mesh, as evidenced by the higher amount of connective tissue and lower extent of fibrous encapsulation.

Incisional abdominal hernia: the open mesh repair.

Mesh techniques are the methods of choice for the repair of incisional hernias since these are due to the formation of unstable scar tissue. We review the materials and techniques used in the repair of incisional hernias. We describe in detail the operative technique performed in our clinic, the pitfalls of the repair, and the overlap behind the xiphoid and the pubic bone. Polypropylene is the material widely used for open mesh repair. New developments have led to low-weight, large-pore polypropylene prostheses, which are adjusted to the physiological requirements of the abdominal wall and permit a proper tissue integration. These meshes provide the possibility of forming a scar net instead of a stiff scar plate and therefore help to avoid former known mesh complications. The ideal position for the mesh is the retromuscular sublay position where the force of the abdominal pressure holds the prosthesis against the deep surface of the muscles. The lowest incidence rates of recurrence have been reported for the retromuscular sublay repair; even after long-term follow-up recurrence rates of 10% are possible. Attaining such good results requires an adequate size of the mesh with sufficient overlap of at least 5-6 cm in all directions. Open mesh repair using modern low-weight polypropylene meshes in the retromuscular sublay technique offers excellent results for the treatment of incisional hernias.

Use of polypropylene prostheses for strangulated inguinal and incisional hernias.

We used monofilament polypropylene prostheses in 20 emergency operations for strangulated hernias. Sixteen of the operated patients had groin hernias (five of them recurrent), two had incisional and one had a Spigel's type hernia. Intestinal resection was performed because of bowel wall necrosis in one of the patients. During the postoperative period, we observed only one minor complication (a seroma formation). During the follow-up, no recurrence was observed. In our opinion, the use of monofilament polypropylene mesh in emergency hernia operations is safe, simple and effective.

Laparoscopic Inguinal Hernia Repair : Review of 6 Years Experience

Since 6 years, the totally extraperitoneal laparoscopic hernia repair has become our procedure of choice to manage inguinal hernia in adult patients, especially for bilateral hernias and recurrences after classical anterior repair. Between March 1993 and March 1999, 976 patients underwent 1259 hernia repairs by an endoscopic total extraperitoneal approach.A large polypropylene prosthesis (15 × 15 cm) is placed and covers all potential defects.Follow-up on patients ranged from 6 to 79 months (mean. 39 months).Per- and postoperative morbidity and complications were acceptable (8.4%) and included conversion to open surgery (0.4%), bleedings (0.3%), urinary retention (4.2%), seromas (2.7%), neuralgias (0.2%), vague persistent groin discomfort (0.4%), orchitis (0.08%) and sigmoido-cutaneous fistula (0.08%).Recurrence rate so far is 0.1%.This retrospective study shows that the totally extraperitoneal repair for inguinal hernia should have a promising future because of low morbidity and low recurrence rate.

Cytokine modifications after tension-free hernioplasty or open conventional inguinal hernia repair

Background: The purpose of this study was to evaluate the involvement of proinflammatory cytokines (interferon-γ [INF-γ], interleukin [IL]-6) and anti-inflammatory cytokines (IL-4, IL-l0, IL-13) in patients undergoing Lichtenstein tension-free hernioplasty (LH) using polypropylene prosthetic materials or conventional Bassini hernia (BH) repair. Methods: Thirty-five male patients (age range 25 to 60 years) with unilateral inguinal hernia without complications or recurrence were included in this study. Randomly, patients underwent conventional operation and had their inguinal hernia repair performed with polypropylene mesh. Peripheral venous blood samples were collected 24 hours prior to surgery and then 6, 24, 48, and 168 hours postoperatively. Fifteen healthy controls were included. Results: We present evidence that LH patients showed both an increased serum level of Thelper 1 (Th1)-like cytokines (IFN-γ) and an increase in Thelper 2 (Th2)-like cytokines (IL-6 and IL-l0), associated with a slight reduction of peripheral blood mononuclear cells (PBMC) producing IL-6 and a normal level of PBMC producing IFN-γ, IL-l0, IL-13, and IL-4. Whereas BH patients showed in part an amplification of Th2-like cells, characterized by the sustained serum production of IL-6 and IL-l0, associated with an increase in IL-l0 secreted by in vitro stimulated PMBC. Conclusions: Our data show that LH is associated with a higher production of inflammatory cytokines (IFN-γ and IL-6) compared with BH, likely induced by the presence of the polypropylene prostheses.

Preperitoneal, minimally invasive, prosthetic groin hernia repair

The study describes the advantages of using the positioning of the prosthesis in the pre-peritoneal space by a posterior approach in the repair of inguinal hernia. The research was carried out on 388 patients (372 (96%) men and 16 (4%) women), who had undergone hernioplasties with the insertion of a polypropylene prosthesis by a preperitoneal approach, between January 1994 and December 1996. 216 of these patients (56%) had an indirect inguinal hernia, 94 (24%) a direct inguinal hernia and 78 (20%) a double inguinal hernia (direct and indirect). In 21 cases (6%) it was a recurrent hernia. The following clinical parameters were considered: pain, sensitivity of the inguinal region, testicular pathology, wound pathology and recurrence. 384 patients out of 388 (99%) were discharged at latest one day after the operation. On average the patients went back to work 6 days after the operation. All the patients were checked at least three times out of four, with follow-ups at 30 days, 6 months, 1 year and 2 years after the operation. In 13 patients (1.8%) there was a minor complication, in 3 patients (0.8%) we found an early recurrence due to technical error. We consider that positioning the prosthesis in the preperitoneal space using this minimally invasive procedure can be carried out easily and with very good clinical results in terms of typical early and/or late complications, which range from 2% to 20% by the anterior approach.

Laparoscopic treatment of inguinal hernias: prospective evaluation of 757 cases treated by a totally extraperitoneal route

The aim was to assess the value of treament of inguinal hernias by a totally extraperitoneal laparoscopic route. Between January 1993 and December 1998, 541 patients (490 men, 51 women) with 757 hernias were operated laparoscopically by a totally extraperitoneal route. Whenever the parietal repair required the insertion of a prosthesis, this was the method chosen. The procedure was perfomed under general anesthesia. One or two polypropylene prostheses of 15 × 12 cm were placed at the deep aspect of the abdominal wall, split but not fixed. The patients were followed up at one, six and twelve months and then annually. The mean operation time decreased with experience, from 66 minutes in 1993 to 47 minutes in 1998 for unilateral hernias and from 104 to 71.5 minutes for bilateral cases. The laparotomy conversion rate was 2%. Mortality was nil. Morbidity was as follows: hemorrhagic scrotal extravasations 10%, serous effusions 3.5%, phebitis 0.3%, pneumopathies 0.3%. The mean period of hospitalization was 2.9 days and the global recurrence rate was 0.6% (4 cases in the first year, 1 case at three years). The totally extraperitoneal laparoscopic route seems to be the method of choice for the treatment of inguinal hernias requiring a prosthesis. It reduces hospital stay and allows earlier return to work and is associated with only minor morbidity and a low recurrence rate.

Evaluation of polypropylene prostheses designed by the International Committee of the Red Cross for trans-tibial amputees.

Thirty-two (32) trained prosthesis users with 34 trans-tibial amputations, mostly due to war, were fitted with prostheses fabricated from polypropylene (PP) prosthetic components designed and manufactured by the International Committee of the Red Cross (ICRC). The patients were followed prospectively for 10 and 19 months. All but one patient had at least one other type of prosthesis to compare with. Twenty-eight (28) patients were satisfied with the PP prosthesis. Among these 23 found the PP prosthesis the preferred artificial limb, and one patient found the PP limb equal to the aluminium prosthesis previously in use. In 6/28 patients having an aluminium (ALU) prostheses this was found the best, and the 1 already mentioned found it equivalent to the new technology. In only 1/20 cases having an Automated Fabrication of Mobility Aids (AFMA) prosthesis available this was found the best. One (1) double-amputee found all three designs equal. Minor failures of the PP prostheses were encountered; in 4 cases small cracks in the hard socket; in 3 cases cracks of the cosmetic socket seam. From an overall prospect the PP technology can be recommended for trans-tibial prostheses.

Preliminary experiences with modified SACH feet manufactured and used in a tropical developing world setting.

In a prospective study of polypropylene (PP) prostheses for trans-tibial amputees four different modified SACH feet were used. These are identified as: 1. BAVI from the national manufacturer of componentry in BaVi; 2. HCMC a design initiated by the International Committee of the Red Cross (ICRC) together with the Army Factory in Ho Chi Minh City; 3. HI from Handicap International; 4. VI from Veterans International, Cambodia. Four (4) from 5 BAVI feet, 7 from 9 HCMC feet and 4 from 10 HI feet failed after about a year on average, whereas none of 10 VI feet had failed after 19 months. Dimensional differences in the ankle part and in the height of the foot in the different designs made interchangeability impossible.

Dynamic self-regulating prosthesis (Protesi Autoregolantesi Dinamica-PAD): A new technique in the treatment of inguinal hernias

Inguinal hernia has been successfully treated using prostheses. However, doubts still remain with regard to tension-free and sutureless techniques, about tension and torsion, wrinkling, prosthesis dislocation and complications in the post-operative phase. We are therefore proposing a new technique, involving the use of a polypropylene prosthesis (Prolene®), known as P.A.D. (Protesi Autoregolantesi Dinamica) which is designed to eliminate these complications. P.A.D. consists of two superimposed layers of surgical mesh. The lower and upper layers of this dynamic prosthesis can move independently from each other, since each is fixed only to one side facing the side of the other layer, allowing for the movement of the aponeurotic and muscular structures. P.A.D. may be used to treat all forms of inguinal hernia in adult males. This study is based on 500 randomly selected male patients with primary inguinal hernias. Excellent results, improved post-operative comfort and recurrence-free follow-up have been observed in all patients treated using this method. There was a significant fall in the consumption of analgesics in the post-operative period, as a result of greater post-operative comfort. P.A.D application is a simple procedure, and is easily replicated.

Tissue response to polypropylene meshes used in the repair of abdominal wall defects

Synopsis The degree of integration of biomaterials used in the repair of abdominal wall defects seems to depend upon the structure of the prosthesis. Several polypropylene (PP) prostheses are currently available which differ in the number of PP filaments, the type of weave and the porosity. The aim of this study was to evaluate the integration, adhesion formation and resistance to traction of three types of PP prostheses (Marlex ®, Trelex ® and Prolene ®) used in the partial or total repair of abdominal wall defects. Abdominal wall defects (7×5 cm) were created in 54 New Zealand rabbits involving all the tissue layers (total substitutions (TS); n=27) or all layers excluding the parietal peritoneum (partial substitutions (PS); n=27). The defects were repaired with PP monofilament prostheses of different weave (1 mm porosity) (Marlex, n=18; Trelex, n=18) or bifilament (2 mm porosity) (Prolene; n=18). They were placed in contact on one side with subcutaneous tissue and on the other with abdominal viscera or parietal peritoneum. Animals were killed at 30, 60 and 90 days and samples of prosthesis and scar tissue processed for light and scanning microscopy. The adhesion formation with viscera was evaluated. Resistance to traction was measured with a tensiometer using strips including the prosthesis and anchorage tissue. Adhesions were detected in all the TS and in four PS. Microscopic analysis revealed total integration of the TS samples by fibrous and disorganized tissue. Prostheses used for PS were integrated by white adipose tissue with the exception of the areas around the mesh nodes and anchorage zones. The foreign body reaction could be seen as a moderate accumulation of white blood cells. Tensiometric analysis showed an increase in resistance to traction with time ( P<0.001) in each type of prosthesis, but no differences were detected ( P>0.001) between them. We concluded that: (a) the formation of adhesions was almost inhibited when the parietal peritoneum was left intact; (b) in both TS and PS, polypropylene prostheses integrated completely although the composition of the scar tissue was seem to differ; and (c) resistance to traction was similar in both TS and PS.

Ventral herniorrhaphy: Treatment evolution in a hernia service

Between 1980 and 1996 the author operated at a teaching academic center and in a private hospital on 230 patients harboring ventral hernias. Fifty hernias were primary and one hundred eighty were incisional. Utilized techniques included direct tissue approximation or overlapping (N=35, recurrence rate 42%), ePTFE or polypropylene prostheses sutured to aponeurotic edges (N=147, recurrence rate 4.7%) and preperitoneal polyester prostheses (N=48, recurrence rate 2%). Nine wound infections occurred: three in clean, three in clean contaminated, and three in infected wounds, producing an overall 3.9 % infection rate. Thirteen markedly obese patients (Quetelet Index 31.9%) with gigantic multiply recurrent hernias offered a serious challenge requiring repeated procedures for recurrence, wound infection and mesh fragmentation. The technical transition leading to preperitoneal approaches utilizing polyester meshes lowered the overall complication rate and has become our procedure of choice until new prostheses are created.

Tension-free hernioplasty: stop and go ambulatory technique

The appearance of the mesh prosthesis on the market determined radical changes in the treatment of groin hernia. There had been no substantial variations for over a century since the invention of Bassini's technique in 1877. The ‘tension-free’ hernioplasty makes the operation easy; it allows the use of local anesthesia and it lowers remarkably the chance of recurrence and complications. In this work the authors, with experience in herniorrhaphy according to Trabucco, illustrate the technique they use to perform the operation in an office-based surgical suite. Moreover, they explain how they eliminate the risk of recurrence that immediate mobilization of the patient and consequent movement of the prosthesis or creation of seroma may cause. In order to avoid these risks, the authors fix the polypropylene prosthesis with human fibrin spray glue. The patients are selected according to their psycho-social characteristics and the operating risk according to the classification of the American Society of Anesthesiology (ASA). They are informed in detail of the method, are treated in an ambulatory fashion, being hospitalized for 2 h on average, are sent home with an analgesic prescription for 24 h and a phone number to use in case of complications. The authors started this method in January 1996 and have treated six patients so far, aged between 23 and 69. The results, although limited and preliminary, have demonstrated the feasibility of the technique, the very good compliance of the patients, the lack of both immediate and belated complications, and the validity of the method regardless of age. A reassuring fact that has been noticed by examining the forms for pain evaluation is the remarkable reduction of pain after the operation compared with patients treated with the traditional Trabucco technique. This fact may be due both to the better preparation of the patients and to the lower mechanical stimulus from the plug covered with fibrin glue.

Use of nonporous polytetrafluoroethylene prosthesis in combination with polypropylene prosthetic abdominal wall implants in prevention of peritoneal adhesions

One of the drawbacks of using macroporous polypropylene prostheses in the repair of the abdominal wall is the formation of adhesions with the viscera. However, polytetrafluoroethylene (PTFE) has low adhesion formation, although it provides less resistance to traction in the repaired zone. The aim of the present study was to reduce the formation of adhesions to a polypropylene implant Prolene® (PL) by introducing a nonporous expanded PTFE layer (Preclude Dura-Substitute®) (PR) between the polypropylene prosthesis and the abdominal viscera. The scarring process and resistance to traction in the repaired zone were also evaluated. Thirty-six rabbits were divided into three groups and were treated as follows: group I, a PR patch (7 × 5 cm) was secured to the parietal peritoneum; group II, an abdominal wall defect (7 × 5 cm) was created and repaired using a PL patch; group III, an abdominal wall defect was as in group II and was repaired using a combined PR/PL prosthesis. Specimens were evaluated at 14, 30, 60, and 90 days postimplant for extent of adhesion formation and morphological analysis was performed using light and scanning electron microscopy. Biomechanical resistance of the implant was evaluated using strips comprising prosthetic material and anchorage tissue. Group I and group III prostheses showed loose adhesions only, but group II adhesions were firmly attached. The mean surface areas covered by adhesions were 0.08 cm2 (group I), 7.67 cm2 (group II), and 0.1 cm2 (group III). PR implants (group I) were encapsulated by organized tissue. In group II the formation of disorganized tissue invading the prosthesis was observed. In group III the PR impeded the growth of disorganized scar tissue and the lower surface of the implant was covered by an orderly neoperitoneum. Resistance to traction of the double implants (group III) (mean ± SD, 33.32 ± 0.9 N) was similar to that of the Prolene implants (group II) (33.76 ± 0.46 N) (Mann-Whitney U test, p < 0.05). We concluded the presence of a PR layer between the PL implant and viscera greatly reduced the incidence of adhesion formation without affecting the high resistance to traction provided by the PL implant or the evolution of the scarring process. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 38: 197–202, 1997

Use of nonporous polytetrafluoroethylene prosthesis in combination with polypropylene prosthetic abdominal wall implants in prevention of peritoneal adhesions.

One of the drawbacks of using macroporous polypropylene prostheses in the repair of the abdominal wall is the formation of adhesions with the viscera. However, polytetrafluoroethylene (PTFE) has low adhesion formation, although it provides less resistance to traction in the repaired zone. The aim of the present study was to reduce the formation of adhesions to a polypropylene implant Prolene (PL) by introducing a nonporous expanded PTFE layer (Preclude Dura-Substitute) (PR) between the polypropylene prosthesis and the abdominal viscera. The scarring process and resistance to traction in the repaired zone were also evaluated. Thirty-six rabbits were divided into three groups and were treated as follows: group I, a PR patch (7 x 5 cm) was secured to the parietal peritoneum; group II, an abdominal wall defect (7 x 5 cm) was created and repaired using a PL patch; group III, an abdominal wall defect was as in group II and was repaired using a combined PR/PL prosthesis. Specimens were evaluated at 14, 30, 60, and 90 days postimplant for extent of adhesion formation and morphological analysis was performed using light and scanning electron microscopy. Biomechanical resistance of the implant was evaluated using strips comprising prosthetic material and anchorage tissue. Group I and group III prostheses showed loose adhesions only, but group II adhesions were firmly attached. The mean surface areas covered by adhesions were 0.08 cm2 (group I), 7.67 cm2 (group II), and 0.1 cm2 (group III). PR implants (group I) were encapsulated by organized tissue. In group II the formation of disorganized tissue invading the prosthesis was observed. In group III the PR impeded the growth of disorganized scar tissue and the lower surface of the implant was covered by an orderly neoperitoneum. Resistance to traction of the double implants (group III) (mean +/- SD, 33.32 +/- 0.9 N) was similar to that of the Prolene implants (group II) (33.76 +/- 0.46 N) (Mann-Whitney U test, p < 0.05). We concluded the presence of a PR layer between the PL implant and viscera greatly reduced the incidence of adhesion formation without affecting the high resistance to traction provided by the PL implant or the evolution of the scarring process.