Seprafilm reduces adhesions to polypropylene mesh and increases peritoneal hydroxyproline

Polypropylene mesh is an effective and widely used material in repairing abdominal wall defects, but it causes dense adhesions when in contact with abdominal viscera directly. As a consequence of this process intestinal obstruction and enterocutaneous fistula may develop. The purpose of the present study was to determine whether Seprafilm, a bioresorbable translucent membrane, reduces abdominal visceral adhesions to polypropylene mesh and whether Seprafilm has any effects on peritoneal tissue hydroxyproline levels. Twenty-six adult Wistar rats were used. A full-thickness abdominal wall defect was created and cecal abrasions were created to induce adhesion formation in each animal. All of the abdominal defects were repaired with polypropylene mesh. In addition a Seprafilm membrane was laid over the abdominal viscera in the Seprafilm group (n = 13). The abdominal cavity was evaluated for adhesion formation, and peritoneal biopsies were taken for the measurement of tissue hydroxyproline levels at the 14th day. The use of Seprafilm resulted in significant reduction in the adhesion formation (P = 0.002) and a significant increase in peritoneal hydroxyproline level (P < 0.0001). These findings demonstrate that the increase of peritoneal hydroxyproline levels caused by Seprafilm might play a role on the antiadhesive effects of Seprafilm.     

Prevention of adhesions to polypropylene mesh

BACKGROUND: Polypropylene mesh used to repair abdominal wall hernias routinely induces dense adhesions if there is direct contact between the mesh and the viscera. Adhesions may lead later to difficult reoperation, intestinal obstruction, or enteric fistula. STUDY DESIGN: A 2.5-cm square defect was surgically created in the rat abdominal wall and replaced with: 1) polypropylene mesh, 2) Sepramesh (SM), or 3) SM plus Seprafilm. Each group included 20 animals. Adhesion area as a percent of the mesh surface was subjectively quantitated by means of laparoscopy and at sacrifice. Evaluations varied from 7 to 28 days after mesh placement. Tissues were harvested at intervals for scanning electron microscopy. RESULTS: Adhesions were complete by day 7, with no change in area thereafter. Adhesion-free mesh surfaces were found on scanning electron microscopy to be carpeted with mesothelial cells from day 5 on. Polypropylene mesh alone induced adhesions in all rats (20/20). The mean area involved was 92%. With SM, 9 of 20 were adhesion-free. The mean area was 15%. When Seprafilm was added to SM, minimal adhesions developed in 5 of 20 rats, the mean area being 2%. Four of the five were single point omental attachments. CONCLUSIONS: 1) Sepramesh alone reduces polypropylene mesh adhesions by roughly three-quarters. 2) Sepramesh plus Seprafilm nearly eliminates such visceral adhesions. 3) Mesothelial cell coverage of polypropylene mesh confers adhesion resistance.     

Bioabsorbable membrane prevents adhesions to polypropylene mesh in rats

Summary Most of mesh materials used in the repair of ventral hernias lead to considerable adhesion formation. In this study we evaluated the effects of a bioabsorbable membrane composed of carboxymethylcellulose and hyaluronic acid (HA membrane) on adhesion formation in the presence of a polypropylene mesh used to repair an incisional hernia model in rats. We repaired the defects either primarily or by polypropylene mesh. The abdominal surface of the repairs were then covered by a piece of HA membrane in randomly selected groups. The presence and grade of adhesions to the repair or mesh were recorded on the 8th day. Tissue specimens were analyzed for the extent of mesothelial and collagenous tissue growth and the degree of inflammation. Dense adhesions developed on all of the defects repaired by polypropylene mesh alone. The HA membrane decreased adhesions significantly when used as a supplement over the mesh (p < 0.01). Histopathologically, the HA membrane further retarded mesothelial growth over the mesh, and decreased vascular proliferation, inflammatory cell infiltration (p < 0.01) and collagen content of the wound (p < 0.05). In our rat model, the HA membrane prevented most of the adhesions that would be expected to occur on the mesh. It decreased the local infiltration of white cells and neovascularization. The HA membrane seemed to be a suitable physical barrier in rats against adhesion formation without compromising the wound healing. However, these findings need to be confirmed in humans.     

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.     

Prevention of intraabdominal adhesions produced by polypropylene mesh

Polypropylene mesh (PPM) is widely used in ventral hernia repair, however is also associated with visceral adhesions when the mesh is exposed to intraabdominal organs. In this study, a composite mesh [ePTFE (expanded polytetrafluoroehylene) + PPM] and sodium hyaluronate/carboxymethyl cellulose (NaHA/CMC) membrane laid under PPM are evaluated in terms of adhesion formation in a rat model of ventral hernia repair. In this experimental study, a 2 x 1 cm of peritoneum and underlying muscle defect was created at the right side of the anterior abdominal wall of 37 male Wistar albino rats. These defects were repaired with 2.5 x 2 cm PPM in group 1 (n = 13), with composite mesh in group 2 (n = 12) and with PPM+NaHA/CMC in group 3 (n = 12). Rats were sacrificed after 14 days and the prosthetic materials were examined for the calculation of surface area percentage covered by adhesions, for organ involvement in the adhesions and for histological evaluation. There was a reduction in the adhesion-covered area in group 2 and group 3. Organ involvement was predominantly seen in group 1. Neoperitoneum was perfect in group 2. Fibrosis and inflammation were higher in group 1. All groups showed adhesiogenic potential to some extent. This potential was maximum with PPM. Both ePTFE and NaHA/CMC displayed similar effects in preventing adhesion formation.     

Prevention of adhesions to polypropylene mesh in a traumatized bowel model

BACKGROUND: Polypropylene mesh (PPM) is an effective material for the repair of abdominal wall defects, but has a tendency to induce dense adhesions when in contact with viscera. Seprafilm (Genzyme Corp, Cambridge, MA), a bioresorbable membrane, has been shown to reduce adhesion formation after midline closures in humans and to PPM in animals. Given the increased inflammatory response expected with surgical trauma, its efficacy under surgical conditions has been questioned. STUDY DESIGN: A prospective, randomized, blinded study was conducted using a rabbit model. Standardized abdominal wall defects were created in three groups of New Zealand white rabbits. The cecum was deserosalized to simulate the effects of trauma. The abdominal defect was then repaired with PPM. In the control group, no Seprafilm was used. In the first experimental group Seprafilm was placed between the mesh and the abdominal viscera. In the second experimental group Seprafilm was placed over the deserosalized area and between the mesh and abdominal viscera. Animals were sacrificed at 30 days and adhesions were categorized and quantified using digital image analysis of inked specimens. The strength of incorporation was also determined. RESULTS: The formation of adhesions between the viscera and mesh repair was dramatically reduced in both experimental groups compared with the control group. The incidence of visceral adhesions was reduced by 80% in the single film group (p = 0.0004) and 90% in the double film group (p = 0.00008). The reduction in surface area of adhesions was 96.4% in the single film group (p = 0.000019) and 99.4% in the double film group (p = 0.00002). Omental adhesions were reduced by 30% but this did not achieve statistical significance. Strength of incorporation was not adversely affected in either group. CONCLUSIONS: Seprafilm is highly effective in preventing adhesions to PPM. This effect was not diminished by the presence of visceral trauma and its resultant inflammatory response. The use of Seprafilm does not adversely affect tissue incorporation. Clinical trials are warranted to determine if the protective effects of Seprafilm demonstrated in this study are applicable in the clinical setting.     

Effectiveness of Hyalobarrier and Seprafilm to prevent polypropylene mesh shrinkage: a macroscopic and histological experimental study

Introduction and hypothesis

Polypropylene (PP) mesh shrinkage represents a serious complication, as a significant cause of pain and recurrence of pelvic organ prolapse or ventral hernias, frequently requiring several surgical interventions. The retraction seems to be caused by the host, in response to the implantation, through the occurrence of periprosthetic adhesions and fibrosis. We hypothesized that avoiding the postoperative adhesions can prevent PP mesh shrinkage.

Methods

Sixty rats were randomly assigned to three groups. A standardized hernia defect was induced on the abdominal wall, which was repaired using an extraperitoneal PP mesh alone (group 1), with application of a hyaluronate carboxymethylcellulose-based bioresorbable membrane (Seprafilm®, group 2), or an auto-cross-linked polysaccharide hyaluronan-based solution (Hyalobarrier® gel, group 3). Eight weeks after the procedure, a repeat laparotomy was performed. After scoring the adhesion and measuring the mesh surface, a microscopic study of the prosthesis-host tissue interfaces was performed.

Results

Group 1 displayed a median shrinkage of 29 % of the mesh. The Seprafilm® group (p?=?0.0238) and Hyalobarrier® gel group (p?=?0.0072) displayed a significantly smaller reduction of 19.12 and 17 %, respectively. Control group 1 displayed a significantly greater adhesion score (30.40) than the Seprafilm® (11.67, p?=?0.0028) and Hyalobarrier® gel groups (11.19, p?=?0.0013). The fibrosis was reduced in the Hyalobarrier® gel group only.

Conclusion

This experimental study revealed that Hyalobarrier® gel and Seprafilm® can prevent PP mesh shrinkage and postoperative adhesions. They might be integrated in a mesh size-saving strategy, which should preserve the quality and durability of the surgical repair and limit the postoperative pain.     

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.     

Human vital amniotic membrane reduces adhesions in experimental intraperitoneal onlay mesh repair

Background  

Various antiadhesive coatings have been proposed for intraperitoneal onlay meshes (IPOM). However, adhesions, mesh infections, and impaired integration remain clinically relevant problems. In this experiment, human vital amniotic membrane (AM) was tested as antiadhesive mesh coating. Vital AM complies with clinical standards of product safety.     

Hyaluronic acid/carboxymethylcellulose membrane barrier versus taurolidine for the prevention of adhesions to polypropylene mesh

BACKGROUND: A hyaluronic acid/carboxymethylcellulose (HA/CMC) membrane is an effective measure to prevent polypropylene mesh induced adhesions. We hypothesized that taurolidine 2% solution might be a cost-effective alternative to decrease adhesion formation. MATERIALS AND METHODS: Twenty-four rats were randomized into three groups: mesh alone (group 1), mesh + taurolidine 2% (group 2), and mesh + HA/CMC (group 3). Polypropylene mesh (4 cm2) was used to repair surgically induced anterior abdominal wall defects. Taurolidine 2%or a HA/CMC membrane was used as an antiadhesive measure. The animals were sacrificed 6 weeks after the operation, and adhesions to the prosthetic material were evaluated with digital image analysis. RESULTS: Group 1 (mesh alone) had the highest adhesion ratio (58.5 +/- 4.8%) compared with groups 2 and 3 (p < 0.05). The differences between groups 2 (mesh + taurolidine 2%; adhesion ratio 42.9 +/- 1.6%) and 3 (mesh + HA/CMC; adhesion ratio 40.3 +/- 3.0%) were not significant (p > 0.05). CONCLUSIONS: The animals of both treatment groups (2 and 3) had lower adhesion ratios compared with the controls (group 1). In particular, the HA/CMC membrane did not present with a superior antiadhesive effect compared with taurolidine. Therefore, taurolidine is a cost-effective alternative to HA/CMC membranes when a polypropylene mesh is used in direct contact with the abdominal viscera.     

Colocutaneous fistula due to polypropylene mesh

Fistulae due to polypropylene mesh are known to occur if the prosthetic mesh is placed close to a hollow viscus. Some cases of enterocutaneous fistula have been reported but there are few cases of fistula affecting the large bowel. It is important to recognize these cases because they are severe complications of the prosthesis and difficult to manage. We present a case of colocutaneous fistula caused by fragmentation of polypropylene mesh and erosion into the sigmoid colon after recurrent incisional hernia repair. Electronic Publication     

Unexpected adhesions to a previously inserted preperitoneal mesh plug

Adhesion formation is a long-term complication of laparoscopic inguinal hernia surgery-particularly by the transabdominal preperitoneal technique; but it is not thought to occur after open repair. We describe a gentleman presenting with a recurrent hernia who had previously undergone an open mesh plug repair 4 years earlier. At laparoscopy he was found to have considerable adhesions associated with the plug. These were successfully divided before repair. This case illustrates the possibility of intra-abdominal adhesions developing even after open hernia surgery.     

Assessment of adhesion formation to intra-abdominal polypropylene mesh and polytetrafluoroethylene mesh

BACKGROUND: The development of intra-abdominal adhesions, bowel obstruction, and enterocutaneous fistulas are potentially severe complications related to the intraperitoneal placement of prosthetic biomaterials. The purpose of this study was to determine the natural history of adhesion formation to polypropylene mesh and two types of polytetrafluoroethylene (ePTFE) mesh when placed intraperitoneally in a rabbit model that simulates laparoscopic ventral hernia repair. MATERIALS AND METHODS: Thirty New Zealand white rabbits were used for this study. A 10-cm midline incision was performed for intra-abdominal access and a 2 cm x 2 cm piece of mesh (n = 60) was sewn to an intact peritoneum on each side of the midline. Two types of ePTFE mesh (Dual Mesh and modified Dual Mesh, W.L. Gore & Assoc., Flagstaff, AZ) and polypropylene mesh were compared. The rate of adhesion formation was evaluated by direct visualization using microlaparoscopy (2-mm endoscope/trocar) at 7 days, 3 weeks, 9 weeks, and 16 weeks after mesh implantation. Adhesions to the prosthetic mesh were scored for extent (%) using the Modified Diamond Scale (0 = 0%, 1 50%). At necropsy the mesh was excised en bloc with the anterior abdominal wall for histological evaluation of mesothelial layer growth. RESULTS: The mean adhesion score for the polypropylene mesh was significantly greater (P < 0.05) than Dual Mesh at 9 weeks and 16 weeks and modified Dual Mesh at 7 days, 9 weeks, and 16 weeks. Fifty-five percent (n = 11) of the polypropylene mesh had adhesions to small intestine or omentum at necropsy compared to 30% (n = 6) of the Dual Mesh and 20% (n = 4) of the modified Dual Mesh. There was a significantly greater percentage (P < 0.003) of ePTFE mesh mesothelialized at explant (modified Dual Mesh 44.2%; Dual Mesh 55.8%) compared to the polypropylene mesh (12.9%). CONCLUSIONS: Serial microlaparoscopic evaluation of intraperitoneally implanted polypropylene mesh and ePTFE mesh in a rabbit model revealed a progression of adhesions to polypropylene mesh over a 16 week period. The pore size of mesh is critical in the development and maintenance of abdominal adhesions and tissue ingrowth. The macroporous polypropylene mesh promoted adhesion formation, while the microporous nature of the visceral side of the ePTFE served as a barrier to adhesions.     

轻量型网片和普通聚丙烯补片在腹股沟疝修补术中的对比研究

目的探讨轻量型网片（强生UPP）在腹股沟疝无张力修补中的作用。方法回顾分析90例次腹股沟疝无张力修补患者的临床资料,其中47例次行普通聚丙烯材料修补,43例次行强生UPP修补。结果强生UPP修补组与普通聚丙烯材料修补组比较,早期并发症发生率（切口疼痛、切口积液、伤口感染、肺部感染、尿道损伤以及尿潴留等）和住院时间差异无统计学意义。在6个月时强生UPP修补组其局部切口疼痛、异物感的患者明显少于普通聚丙烯材料修补组,腹壁顺应性明显好于普通聚丙烯材料修补组,在6个月时两组均没有复发。结论轻量型网片在腹股沟疝无张力修补中,其后期并发症明显减少,有望成为腹股沟疝无张力修补的首选材料。     

Abdominal adhesions to prosthetic mesh evaluated by laparoscopy and electron microscopy

BACKGROUND: Most adhesion experiments involve observations at a single time point. We developed a method to evaluate abdominal adhesions to surgical mesh by sequential laparoscopy. STUDY DESIGN: An abdominal wall defect was created in rats and repaired with polypropylene mesh. Sequential laparoscopic evaluation of adhesion formation was performed in each animal. The percentage of mesh area involved was scored (0% to 100%). At various time intervals animals were sacrificed and samples were obtained for light and scanning electron microscopy. RESULTS: Adhesions were already present on day 1, increased by day 7, and did not progress thereafter. Mesh surfaces free of adhesions were covered with a confluent mesothelial cell layer, first seen by scanning electron microscopy on day 5 and complete by day 7. CONCLUSIONS: Intraabdominal adhesions are best studied by sequential laparoscopy. Adhesions develop within 1 day of prosthesis placement. Adhesion-free surfaces are carpeted with mesothelial cells by day 7 and remain free thereafter, for duration of study.