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

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.     

Seprafilm reduces adhesions to polypropylene mesh

BACKGROUND: Adhesions to polypropylene mesh used for abdominal wall hernia repair may eventuate in intestinal obstruction or enterocutaneous fistula. A Seprafilm Bioresorbable Membrane translucent adhesion barrier has been shown to inhibit adhesions. This investigation was designed to determine if Seprafilm alters abdominal visceral adhesions to polypropylene mesh. METHODS: A 2.5-cm square abdominal muscle peritoneal defect was created and corrected with polypropylene mesh. Mesh alone was used in 17 rats. In another 17, the Seprafilm membrane was applied between the viscera and the mesh. Five animals had the bioresorbable membrane placed in the subcutaneous space and between the mesh and the viscera. Laparoscopy was performed 7, 14, and 28 days later to evaluate adhesions as a percentage of mesh surface involved. RESULTS: Polypropylene mesh alone was associated with adhesions in every rat. The average area involved was 90%, the minimum was 75%. Adhesions were present within 24 hours and progressed up to 7 days with no change thereafter. When the Seprafilm barrier was used, the mean area involved was 50%. In 16 such rats, the area involved was smaller than any control animal. No adhesions formed in 5 animals. Scanning electron microscopy demonstrated a mesothelial cell layer covering the mesh after 4 weeks. CONCLUSIONS: The use of the Seprafilm adhesion barrier resulted in a significant reduction of adhesion formation to polypropylene mesh (P <.001).     

Hyaluronic acid/carboxymethylcellulose membrane surrounding an intraperitoneal or subcutaneous jejunojejunostomy in rats.

OBJECTIVE: To investigate the healing of intra-abdominal and extra-abdominal jejunal anastomoses that were surrounded by a hyaluronic acid/carboxymethylcellulose membrane (Seprafilm) in rats. DESIGN: Laboratory study. SETTING: University hospital, The Netherlands. ANIMALS: 56 male Wistar rats. INTERVENTIONS: 28 rats had jejunojejunostomies placed subcutaneously and 28 had them placed intra-abdominally. Half of each group of anastomoses were surrounded by Seprafilm. MAIN OUTCOME MEASURES: After 3 or 7 days, the anastomoses were tested for bursting pressure, tensile strength, and hydroxyproline concentrations. RESULTS: There were numerous strong adhesions around the anastomoses in the subcutaneous position and Seprafilm had no influence on their extent. Bursting pressure and hydroxyproline concentrations were not affected by position or Seprafilm treatment. Tensile strength was significantly higher in the subcutaneous position (p < 0.01), but was unaffected by Seprafilm. CONCLUSION: Anastomotic healing was not impaired in the subcutaneous or intraperitoneal position in this model. Seprafilm had no effect on the anastomosis.     

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.     

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 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.     

Suture versus preperitoneal polypropylene mesh for elective umbilical hernia repairs

Background

Repair of primary ventral hernias (PVH) such as umbilical hernias is a common surgical procedure. There is a paucity of risk-adjusted data comparing suture versus mesh repair of these hernias. We compared preperitoneal polypropylene (PP) repair versus suture repair for elective umbilical hernia repair.

Methods

A retrospective review of all elective open PVH repairs at a single institution from 2000–2010 was performed. Only patients with suture or PP repair of umbilical hernias were included. Univariate analysis was conducted and propensity for treatment-adjusted multivariate logistic regression.

Results

There were 442 elective open PVH repairs performed; 392 met our inclusion criteria. Of these patients, 126 (32.1%) had a PP repair and 266 (67.9%) underwent suture repair. Median (range) follow-up was 60 mo (1–143). Patients who underwent PP repair had more surgical site infections (SSIs; 19.8% versus 7.9%, P < 0.01) and seromas (14.3% versus 4.1%, P < 0.01). There was no difference in recurrence (5.6% versus 7.5%, P = 0.53). On propensity score–adjusted multivariate analysis, we found that body mass index (odds ratio [OR], 1.10) and smoking status (OR, 2.3) were associated with recurrence. Mesh (OR, 2.34) and American Society of Anesthesiologists (OR, 1.95) were associated with SSI. Only mesh (OR, 3.41) was associated with seroma formation.

Conclusions

Although there was a trend toward more recurrence with suture repair in our study, this was not statistically significant. Mesh repair was associated with more SSI and seromas. Further prospective randomized controlled trial is needed to clarify the role of suture and mesh repair in PVH.     

Prevention of adhesions by bioresorbable tissue barrier following laparoscopic intraabdominal mesh insertion

Intraabdominal adhesions represent a significant problem because of the morbidity associated with adhesive disease, including small bowel obstruction, difficulties in reoperative surgery, and possibly chronic pain. Coating solution of sodium hyaluronate (Sepracoat; Genzyme Production-Surgical Products, Cambridge, MA) was studied in New Zealand white rabbits to determine its potential role for prevention of postoperative adhesions following laparoscopic intraabdominal mesh insertion. A 2-cm polypropylene mesh was inserted laparoscopically to the left iliac fossa and fixed to anterior abdominal wall using a single prolen suture. Group 1 (n = 10) acted as the control group. Mesh was coated using 4% sodium hyaluronate in phosphate buffered saline (Sepracoat) in Group 2 (n = 10). Fourteen days later, all animals underwent diagnostic laparoscopy, and findings were recorded. All animals then were killed, the abdominal cavities were inspected, and adhesions were graded from 0 to 4. All meshes were removed and sent for histologic examination. The degrees of inflammation, fibrosis, and congestion were scored. No adhesions were seen on trocar sites on both groups. Eight of 10 animals in the control group and 5 of 10 animals in the study group had intraabdominal adhesions. The scoring of adhesions revealed that study group had only one (10%) significant adhesion, whereas the control group had eight (80%; < 0.001). Our study suggests that the Sepracoat reduces the incidence and severity of abdominal adhesions following laparoscopic mesh insertion and should be considered as a prophylactic agent, especially in those undergoing laparoscopic transabdominal mesh repair for hernia.     

Shrinkage of intraperitoneal onlay mesh in sheep: coated polyester mesh versus covered polypropylene mesh

Background  

Currently, the laparoscopic placement of intraperitoneal mesh constitutes an acceptable option in the management of ventral hernia. To date, relatively little has been published on the consequences of intra-abdominal placement of a mesh with respect to the decrease of mesh size (shrinkage).     

Evaluation of hyaluronic acid sheet for the prevention of postlaminectomy adhesions.

BACKGROUND CONTEXT: Various materials have been tested for their ability to maintain a barrier between muscles and epidural space in order to physically or chemically inhibit scar ingrowths. Hyaluronic acid (HA) solution and gel have been reported to be effective in preventing adhesions postlaminectomy; however, neither has been used clinically after spinal surgery. PURPOSE: To determine the efficacy of HA sheet for the prevention of postlaminectomy adhesions compared with that of HA gel or another sheet. STUDY DESIGN/SETTING: An animal model of lumbar laminectomy in rabbits was used to study postoperative scar tissue formation around the spinal cord. The histologic effects of HA sheet were compared with those of Gelfoam (GF) and further evaluated by an inflammation model using rhTNF-alpha. PATIENT SAMPLE: Rabbit. OUTCOME MEASURES: Histologic examination. METHODS: Five rabbits were killed at 2, 4, 8, and 24 weeks after laminectomy, respectively. Another 18 rabbits were examined in an environment of active inflammation experimentally induced by rhTNF-alpha to compare the effects of HA sheet with those of GF or HA gel. Histologic examination was performed to quantitatively assess invasive scar formation or inflammation postlaminectomy, and then, the histologic effects of HA sheet were compared with those of GF or HA gel. RESULTS: In the HA group, significantly, the area of subarachnoid space was larger, distance from the surface of dura to scar tissues was greater, the number of inflammatory cells in the scar tissues at the site of laminectomy was less, and enlargement of dura was suppressed. Using an inflammation model, we also demonstrated the efficacy of HA sheet treatment. CONCLUSIONS: In an experimental laminectomy model, HA sheet formed a solid interpositional membrane barrier and exhibited anti-inflammatory activity. Further investigations will be needed for HA sheet to be used clinically.     

Role of a hyaluronate-based membrane in the prevention of peritonitis-induced adhesions

Adhesions remain a significant postoperative complication of abdominal surgery; however, recent evidence suggests that physical barriers may reduce their incidence. Although these adhesion prevention barriers are efficacious when used under aseptic conditions, little is known about their use in the presence of peritonitis, which is associated with an increased incidence of abdominal adhesions. A sodium hyaluronate and carboxymethylcellulose bioresorbable membrane (HA membrane) has been shown recently to reduce postoperative adhesions in several animal models and in two clinical trials. To investigate the efficacy of HA membrane in the presence of peritonitis, generalized peritonitis was induced in rats by either cecal ligation and puncture (CLP) or cecal ligation (CL) alone. The ceca were resected after 12 hours, and animals were randomly assigned to receive or not receive HA membrane applied to the cecum. At day 7, abdominal adhesions and abscesses were scored. In the presence of peritonitis, HA membrane did not significantly reduce the number or tenacity of adhesions. A trend toward increased abscess formarion was associated with HA membrane in the CL group. Although HA membrane has been shown to reduce the incidence and severity of abdominal adhesions under aseptic conditions, this study demonstrates that it is not efficacious in preventing abdominal adhesions in the presence of peritonitis. The association between HA membrane and abscess formation in the presence of experimental peritonitis requires further investigation. Supported by the Genzyme Corporation, Cambridge, Mass. Presented at the Fortieth Annual Meeting of The Society for Surgery of the Alimentary Tract, Orlando, Fla., May 16–19, 1999.     

A novel instrument and technique for using Seprafilm hyaluronic acid/carboxymethylcellulose membrane during laparoscopic myomectomy

Myomectomy is associated with the development of adhesions, and even when the patient is operated on laparoscopically, postoperative adhesions can often occur. Seprafilm is an effective and highly safe barrier to postoperative adhesions. However, it is vulnerable to tears and difficult to handle. We developed a device to introduce Seprafilm into the abdominal cavity during the laparoscopic procedure. Seprafilm is divided into 6 pieces and the pieces are rolled and inserted into the purpose-built introducer to be guided into the abdominal cavity. The inner syringe is pushed in and Seprafilm is applied onto the uterine wound with two grasping forceps. Of 117 patients in our study, we were able to use Seprafilm on 114 patients (97.4%). In total, 221 pieces of Seprafilm were used, and 87 pieces were damaged during the operation. Of these 87 pieces, 58 were damaged when inserted into the introducer, though this kind of loss tended to decrease with training, and 29 pieces were damaged during application to the wound. Seprafilm can be used safely and efficiently during laparoscopic surgery.     

猪小肠黏膜下层脱细胞基质补片与轻量聚丙烯补片在腹股沟疝Lichtenstein修补术中的对比研究

目的探讨猪小肠黏膜下层脱细胞基质（porcine small intestine submucosa,SIS）补片对比轻量聚丙烯（polypropylene mesh,PP）补片在腹股沟疝Lichtenstein修补术中应用的安全性和短期疗效。 方法回顾性分析2012年1月至2015年8月,中山大学附属第一医院使用SIS补片和轻量PP补片做单侧腹股沟疝Lichtenstein修补术的连续男性病例资料,SIS组和PP组分别纳入64例,比较2组患者手术安全性和短期疗效。 结果SIS组与PP组在术后24 h疼痛评分、发热、伤口脂肪液化、血清肿、尿潴留、睾丸并发症发生率比较,差异无统计学意义（P均>0.05）。2组均无手术部位感染和血肿发生病例。2组均无复发病例。SIS组在术后慢性疼痛（14.1%比15.6%,χ²=0.062,P=0.804）,术后腹股沟区不适感（12.5%比17.2%,χ²=0.556,P=0.456）,异物感（3.1%比4.7%,P=1.000）均低于PP组,但2组差异无统计学意义（P均>0.05）。2组在术后均无明显射精疼痛或障碍,无睾丸萎缩。PP组有2例（3.1%）患者出现手术侧睾丸肿大。 结论SIS补片对比轻量PP补片在腹股沟疝Lichtenstein修补术中应用的安全性和短期疗效是相当的,其长期疗效仍有待进一步观察。     

Preventing intraperitoneal adhesions with linezolid and hyaluronic acid/carboxymethylcellulose: a comparative study in cecal abrasion model

Background

We aimed to compare the effectiveness of linezolid in preventing intraperitoneal adhesions with hyaluronic acid + carboxymethylcellulose (Seprafilm).

Methods

Thirty rats were divided randomly into 3 groups: Group I (control), untreated; Group II (Seprafilm); and Group III (linezolid). All rats were sacrificed on the 14th day after surgery. Macroscopic adhesion, inflammation, and fibrosis were evaluated.

Results

The multiple comparisons between groups showed a statistically significant difference for adhesion. There were statistically significant differences between Group I and II and I and III, but no statistically significant difference between Group II and III. The multiple comparisons between the groups showed a statistically significant difference for inflammation and fibrosis. For inflammation and fibrosis, there was a statistically significant difference between Group I and II and I and III, but no statistically significant difference between Group II and III.

Conclusion

The efficiency of linezolid in reducing the formation of intraperitoneal adhesions was statistically significant compared with the control group.