Prevention of adhesion formation to polypropylene mesh by collagen coating: A randomized controlled study in a rat model of ventral hernia repair

Introduction In laparoscopic incisional hernia repair with intraperitoneal mesh, concern exists about the development of adhesions between bowel and mesh, predisposing to intestinal obstruction and enterocutaneous fistulas. The aim of this study was to assess whether the addition of a collagen coating on the visceral side of a polypropylene mesh can prevent adhesion formation to the mesh.Method In 58 rats, a defect in the muscular abdominal wall was created, and a mesh was fixed intraperitoneally to cover the defect. Rats were divided in two groups; polypropylene mesh (control group) and polypropylene mesh with collagen coating (Parieten mesh). Seven and 30 days postoperatively, adhesions and amount and strength of mesh incorporation were assessed. Wound healing was studied by microscopy.Results With Parieten mesh, the mesh surface covered by adhesions was reduced after 30 days (42% vs 69%, p = 0.01), but infection rate was increased after both 7 (p = 0.001) and 30 days (p = 0.03), compared to the polypropylene group with no mesh infections. If animals with mesh infection were excluded in the analysis, the mesh surface covered by adhesions was reduced after 7 days (21% vs 76%, p = 0.02), as well as after 30 days (21 vs 69%, p < 0.001). Percentage of mesh incorporation was comparable in both groups. Mean tensile strength of mesh incorporation after 30 days was higher with Parieten mesh.Conclusion Although the coated Parieten mesh was more susceptible to mesh infection in the current model, a significant reduction of adhesion formation was still seen with the Parieten mesh after 30 days, with comparable mesh incorporation in the abdominal wall.     

Laparoscopic versus open ventral hernia repair: a randomized controlled trial

Laparoscopic and open techniques are both recognized treatment options for ventral hernias. We conducted a prospective randomized trial of both methods, to assess hernia recurrence, postoperative recovery and complications. Fifty-eight patients with ventral hernias were enrolled into the trial between August 2003 and December 2005. Of these, 31 underwent laparoscopic repair and 27 underwent open repair. Clinical parameters were documented on all patients during a median follow-up period of 27.5 months. The demographics of the two groups were similar. There was one recurrence in each of the laparoscopic and open groups. There was an equivalent rate of operative time, length of stay, postoperative pain scores, return to normal activities, wound infection and seroma formation between the two groups. Laparoscopic and open ventral hernia repair are comparable and offer low recurrence rates.     

Effect of prosthetic material on adhesion formation after laparoscopic ventral hernia repair in a porcine model

Intraperitoneal placement of prosthetic mesh causes adhesion formation after laparoscopic incisional hernia repair. A prosthesis that prevents or reduces adhesion formation is desirable. In this study, 21 pigs were randomized to receive laparoscopic placement of plain polypropylene mesh (PPM), expanded polytetrafluoroethylene (ePTFE), or polypropylene coated on one side with a bioresorbable adhesion barrier (PPM/HA/CMC). The animals were sacrificed after 28 days and evaluated for adhesion formation. Mean area of adhesion formation was 14% (SD±15) in the PPM/HA/CMC group, 40% (SD±17) in the PPM group, and 41% (SD±39) in the ePTFE group. The difference between PPM/HA/CMC and PPM was significant (P=0.013). A new visceral layer of mesothelium was present in seven out of seven PPM/HA/CMC cases, six out of seven PPM cases, and two out of seven ePTFE cases. Thus, laparoscopic placement of PPM/HA/CMC reduces adhesion formation compared to other mesh types used for laparoscopic ventral hernia repairs.This work was presented as an oral presentation at the American Hernia Society Meeting, Tucson, Ariz. USA in May, 2002.This study was funded by a grant from Genzyme, Corp., Cambridge, Mass. USA     

Prevention of postoperative intrapleural adhesion of the thoracotomy incision by a bioresorbable membrane in the rat adhesion model.

For the purpose of reducing the risk of lung injury while separating adhesions in repeated pulmonary resections, the inhibitory effect of hyaluronate based bioresorbable membrane (HA membrane) on postoperative adhesions was investigated in a new pleural adhesion model in rats. First of all, a novel post-thoracotomy adhesion model in rats was successfully established by using a combination of mechanical, chemical and ischemic injuries of the pleura during operation. After undergoing the same adhesion-inducing procedures, one of two groups was treated with HA membrane inserted between the lung and the parietal pleura, and the other group underwent infusion of saline only. The severity of the adhesion formation was macroscopically lower in the HA membrane-treated rats, and they had favorable mesothelial regeneration microscopically. Additionally, the activity of type 1 plasminogen activator inhibitor (PAI-1) in the intrapleural lavage fluid (ILF) was measured at 24 hours postoperatively because this is the main influence on adhesion formation after surgery. PAI-1 activity was 23.37+/-2.57 U/ml in the saline-treated group and 17.85+/-3.06 U/ml in the HA membrane-treated group. The result suggests that the HA membrane inhibits postoperative adhesion formation through a significant repression of PAI-1 activity.     

Adhesion formation after laparoscopic ventral incisional hernia repair with polypropylene mesh: a study using abdominal ultrasound.

OBJECTIVE: Laparoscopic repair of ventral incisional hernias is feasible and safe. Polypropylene mesh is often preferred because of its ease of handling and lower cost. Complications like adhesion and fistula formation can occur. The goal of this study was to determine whether bowel adhesions and their attendant complications could be prevented by interposition of omentum. METHODS: Thirty patients underwent laparoscopic ventral incisional hernias repair with polypropylene mesh. Omentum was always positioned over the loops of bowel for protection. At a mean follow-up of 14 months, 20 patients underwent ultrasonic examination using the previously described visceral slide technique to detect adhesions. RESULTS: The mean size of the hernias in the study was 50.3 cm2, and the mean size of the mesh applied was 275 cm2. Thirteen patents (65%) had no sonographically detectable adhesions. Five patients demonstrated adhesions between the mesh and omentum, 1 patient developed adhesions between the left lobe of the liver and the mesh, and only 1 case of bowel adhesion to the edge of the mesh was found. CONCLUSION: Laparoscopic ventral incisional hernias repair with polypropylene mesh and omental interposition is not associated with visceral adhesions in the majority of patients. Polypropylene mesh can be used safely when adequate omental coverage is available.     

Use of resterilized polypropylene mesh in inguinal hernia repair: a prospective, randomized study

BACKGROUND: Inguinal hernia repair consumes considerable health-care resources worldwide. Open mesh repairs are commonly used and the feasibility of using a resterilized mesh, which is a general practice in certain countries, has not been evaluated. STUDY DESIGN: In this randomized prospective study, original and resterilized meshes were used in two groups of patients with unilateral inguinal hernia. Microbiologic changes, textile mechanical properties, overall complication rates, and cost-effectiveness of resterilized mesh were investigated. A time period of 3 years was determined for patient enrollment to this pilot feasibility study, with the goal of 100 patients in each group. RESULTS: Ninety-one patients were enrolled in the original group and 93 in the resterilized mesh group. Median followup was 735 and 739 days and calculated interquartile ranges were 454 and 513 days, respectively. Average tensile strength of the original polypropylene mesh changed slightly with resterilization, as maximum load decreased from a mean of 66.6 to 58.2 N/cm. Overall complication rates were similar in the two groups. The 6.6% infection rate in the original mesh group was not statistically different from the 7.5% rate in the resterilized group (p = 0.80, relative risk = 0.88, 95% confidence interval, 0.31-2.51). There was only one recurrence in the original mesh group in the 21st month. Use of a resterilized mesh decreased the overall cost of operation by decreasing the cost of mesh from 15.9% to 8.3% of the total amount. CONCLUSIONS: Use of a resterilized mesh for inguinal hernia repair is feasible without considerable changes in infection and recurrence rates.     

A comparative study of adhesion formation and abdominal wall ingrowth after laparoscopic ventral hernia repair in a porcine model using multiple types of mesh

Background The ideal mesh for laparoscopic ventral hernia repair is not yet identified.Methods We laparoscopically placed polypropylene (PPM), expanded polytetrafluoroethylene (ePTFE), and polyester with antiadhesive collagen layer (PCO) in eight pigs using sutures and tacks for fixation. After 28-day survival, we compared adhesion formation, fibrous ingrowth, and shrinkage among the types of mesh.Results Mean area of adhesions to PCO (8.25%) was less than that to ePTFE (57.14%, p < 0.001) or PPM (79.38%, p < 0.001). Adhesions peel strength was less for PCO (2.3 N) than for PPM (16.1 N, p < 0.001) or ePTFE (8.8 N, p = 0.02). Peel strength of mesh from the abdominal wall was less for ePTFE (1.3 N/cm of mesh width) than for PCO (2.8 N/cm, p = 0.001) or PPM (2.1 N/cm, p = 0.05). ePTFE area (94.4 cm²) was less than that for PCO (118.6 cm², p < 0.001) or PPM (140.7 cm², p < 0.02).Conclusion PCO had fewer and less severe adhesions than ePTFE or PPM while facilitating excellent ingrowth of the adjacent parietal tissue.     

Shrinkage evaluation of heavyweight and lightweight polypropylene meshes in inguinal hernia repair: a randomized controlled trial

Background  

One of the current complications in inguinal repair is shrinkage following the use of mesh. The selected mesh material, heavyweight (HWM) mesh or lightweight (LWM) mesh, is associated with the frequency of shrinkage. The aim of this study was to investigate shrinkage of these two types of mesh in a controlled trial of male inguinal hernia repair.     

Dermal collagen matrices for ventral hernia repair: comparative analysis in a rat model

Purpose

The purpose of this study was to compare inflammatory responses, tissue integration, and strength of the acellular dermal collagen matrices AlloDerm^?* Regenerative Tissue Matrix, Permacol?**Surgical Implant (Permacol), and CollaMend?*** Implant in a rat model for ventral hernia repair.

Methods

Rats were randomized into four groups and abdominal wall defects repaired with an inlay graft of AlloDerm, Permacol, or CollaMend. Rats were sacrificed at six time points and the defect area was removed and analyzed for tissue integration and physical strength.

Results

Variable cell infiltration was seen for the three implant groups. At of the all time points examined, cellular infiltration was most rapid in the AlloDerm implants and slowest for CollaMend. At 14?days, significant cell infiltration along with putative blood vessel formation was observed for AlloDerm, while Permacol implants exhibited a moderate level of infiltration. Very few cells penetrated CollaMend implants at 2?weeks. Cells had reached the center of the Permacol implants by 1?month, whereas CollaMend implants were encapsulated with a loose coat of disconnected cells, with very few cells infiltrating past the surface. At 6?months, AlloDerm and Permacol had evidence of cell penetration throughout the implants, while the CollaMend samples exhibited limited infiltration. Animals for each implant developed seromas: AlloDerm 40%, Permacol 33%, and CollaMend 83%. Mechanical testing revealed that AlloDerm at 6?months showed the lowest tensile strength, CollaMend the highest, and Permacol an intermediate level.

Conclusions

The three biologics exhibited different patterns and rates of cellular and vascular permeation in our rat model. AlloDerm implants exhibited the most rapid and extensive cellular infiltration, followed by Permacol. However, on gross examination, the AlloDerm implants thinned significantly by 6?months. In contrast, the Permacol and CollaMend implants appeared to be largely intact.     

Development of a dynamic model for ventral hernia mesh repair

Introduction

The adequate way of mesh fixation in laparoscopic ventral hernia repair is still subject to debate. So far, simulation has only been carried out in a static way, thereby omitting dynamic effects of coughing or vomiting. We developed a dynamic model of the anterior abdominal wall.

Materials and methods

An aluminium cylinder was equipped with a pressure controlled, fluid-filled plastic bag, simulating the abdominal viscera. A computer-controlled system allowed the control of influx and efflux, thus creating pressure peaks of up to 200 mmHg to simulate coughing and 290 mmHg to simulate vomiting. We tested fixation with tacks (Absorbatack, Covidien Deutschland, Neustadt a. D., Germany). The model was controlled for the friction coefficient of the tissue against the mesh and the physiologic elasticity of the abdominal wall surrogate.

Results

The model was able to create pressure peaks equivalent to physiologic coughs or vomiting. Physiologic elasticity was thereby maintained. We could show that the friction coefficient is crucial to achieve a physiologic situation. The meshes showed a tendency to dislocate with an increasing number of coughs (Fig. 4). Nevertheless, when applied in a plain manner, the meshes withstood more cough cycles than when applied with a bulge as in laparoscopic surgery.

Conclusions

The dynamic movement of the abdominal wall, the friction between tissue and mesh and the way of mesh application are crucial factors that have to be controlled for in simulation of ventral abdominal hernia closure. We could demonstrate that patient specific factors such as the frequency of coughing as well as the application technique influence the long term stability of the mesh.     

Fascial defect closure versus bridged repair in laparoscopic ventral hernia mesh repair: a systematic review and meta-analysis of randomized controlled trials

Hernia - Several studies have examined effectiveness of primary fascial defect closure (FDC) versus bridged repair (no-FDC) during laparoscopic ventral hernia mesh repair (LVHMR). The purpose of...     

Laparoscopic ventral hernia repair using a composite mesh with polypropylene and expanded polytetrafluoroethylene: a prospective,multicentre registry

Background: Abdominal wall hernias are a common problem. Composite meshes placed intraperitoneally for abdominal wall hernia repair are widely used. This registry evaluated the safety and efficacy of one specific composite mesh with polypropylene and expanded polytetrafluoroethylene (Intramesh^® T1) in laparoscopic ventral hernia repair.

Methods: A prospective multicentre registry with data from seven centres was collected between January 2013 and September 2014. Primary endpoint was recurrence rate at 12 months determined by clinical examination. Secondary outcome measures included intraoperative complications, complications during hospitalisation and at 1-month and 12-months follow-up.

Results: The registry included 90 patients (30 female and 60 male). Fifty-five patients (61.1%) presented with primary ventral hernias and 35 patients (38.9%) with incisional ventral hernias. Median hernia size was 4?cm². Intraoperative complications were reported in two patients (2.2%). Complications during hospitalisation were reported in four (4.4%) patients. At 1-month follow-up, 17 (18.9%) patients had postoperative complications, of which 5 complications were major and 19 were minor. Late complications at 12-months were observed in 10 patients (11.1%), of which 2 were major and 8 minor complications.

Conclusion: Intramesh^® T1 is a safe and effective composite mesh with favourable short and midterm outcome and morbidity. (NCT01816867)     

A randomized, controlled, clinical study of laparoscopic vs open tension-free inguinal hernia repair

Background: The aim of this prospective, randomized, controlled clinical study was to compare laparoscopic transabdominal preperitoneal (TAPP) hernia repair with a standard tension-free open mesh repair (open). Methods: A total of 108 low-risk patients with unilateral (primary or recurrent) or bilateral hernias were randomized to TAPP (group 1 = 52 cases) or open (group 2 = 56 cases). The outcome measures included operating time, complications, postoperative pain, return to normal activity, operating theater costs, and recurrences. Results: The mean operative time was longer for the TAPP than for the open group only in unilateral primary hernias. At rest, the median Visual Analog Scale (VAS) score was higher for group 1 than group 2 at 48 h postoperatively. Mild to discomforting pain in the inguinal region after 7 days, night pain after 30 days, and inguinal hardening after 3 months were more frequent in group 2 than group 1. No significant differences were observed in return to normal activities between the groups. One hernia recurrence was observed after 1 month in group 1. TAPP was significantly more expensive than open. Conclusions: TAPP was associated with less postoperative pain than open. The increase in operating theater costs, however, was dramatic and was not compensated by shorter time away from work. TAPP should not be adopted routinely unless its costs can be drastically reduced. Received: 10 June 1997/Accepted: 6 October 1997     

疝修补材料的发展与新进展

目的 对比分析轻型聚丙烯补片与标准型聚丙烯补片在腹股沟疝无张力修补术中的应用价值.方法 实验组使用轻型聚丙烯补片,对照组使用标准型聚丙烯补片,每组各30例患者.记录两组患者手术前后的临床参数及术后各种并发症的发生例数,并对数据进行统计学分析. 结果 经统计分析,两组患者在手术时间、术后的最高体温、术后住院日数、术后C-反应蛋白升高的例数以及术前与术后24 h的血白细胞计数、中性粒细胞分类计数和生化的谷丙转氨酶、谷草转氨酶、尿素氮、肌酐的数值等方面均无显著性差异.术后随访6个月,两组均未出现伤口感染、复发、男性患者的睾丸肿大/萎缩.实验组术后有2例出现阴囊积液,1例出现慢性疼痛,没有局部异物感发生;对照组术后有3例发生阴囊积液,3例出现慢性疼痛,6例出现局部异物感.经统计学分析,两组除局部异物感的发生率有显著性差异(P<0.05)外,其它并发症方面的差异无统计学意义.结论 轻型聚丙烯补片在腹股沟疝无张力修补术中的应用是安全有效的;由于其轻质轻量、大网孔、高弹性的特点,可减少术后局部异物感的发生.     

Prospective double-blind randomized controlled study comparing heavy- and lightweight polypropylene mesh in totally extraperitoneal repair of inguinal hernia: early results

Background  Success of totally extraperitoneal (TEP) inguinal herniorrhaphy depends upon strengthening of the weakened native tissue by inflammation resulting in mesh–aponeurosis scar tissue (MAST) complex formation. The inflammatory response attributable to polypropylene (PP) content of the mesh is linked to weight of PP and pore size of the mesh. Continuation of the inflammatory process beyond MAST complex formation can entrap contiguous structures, leading to adverse outcome such as groin pain. Reduction of PP content has been shown to be beneficial in animal studies. Paucity of randomized controlled trials (RCTs) on human beings has left choice of mesh to surgeon preference or cost. We carried out a double-blind RCT comparing heavy- and lightweight PP-based meshes in TEP. Patients and methods  Consecutive, married, sexually active male candidates for bilateral TEP herniorrhaphy were enrolled without any exclusion, with ethical and informed consent protocol. Standard TEP technique was followed for day-care surgery. Heavy- and lightweight meshes were implanted in each patient, one in either groin after randomization. Surgeon and patient were blinded to side of groin and type of mesh. An independent doctor (AID) evaluated the patients for groin pain, discomfort, sexual dysfunction, and clinical recurrence. A nonmedical secretary/AID transferred prospective data for both sides of groin collected by AID to Microsoft Excel. Results  Twenty-five bilateral TEPs implanting 25 heavy- and 25 lightweight PP meshes, one of each type in each patient, were performed from December 2005 to July 2007 without difficulty or complication. Lightweight PP mesh was associated with significantly better pain scores, patient comfort, and sexual function. There was no infection or recurrence with either type of mesh. Conclusion  Lightweight PP mesh is associated with significantly better outcomes in TEP inguinal herniorrhaphy as compared with heavyweight PP mesh. This work was presented at the SAGES 2008 meeting as an oral paper (abstract ID 19,025) and at the 11th World Congress of Surgery held at Yokohama, Japan as an oral paper (abstract ID WWS13-2).     

腹股沟疝无张力修补术前后入路前瞻性对照研究(附263例报告)

目的 通过比较前入路（常规疝手术）和后入路（腹膜前）无张力疝修补方法治疗腹股沟疝病人的手术时间、住院时间等情况，评价两种手术方法的疗效。方法 2001年8月至2005年7月，采用前瞻性随机对照方法，将263例病人275侧腹股沟疝（其中12例同时患有双侧疝）随机分为前入路组（132例）和后入路组（131例）。前入路组用假体的无张力修补（Liehtenstein术式45例，Rutkow术式87例），后入路组用单层网片修补。结果 前入路组平均随访32．2个月，后入路组为31．8个月。两组病人的平均手术时间、平均住院时间、手术并发症和术后复发率差异无显著性意义。在平均费用方面，后入路组明显少于前入路组（P〈0．05），术后腹股沟区疼痛不适的发生率也明显降低。结论 采用后入路方法进行腹股沟疝修补，可明显减少手术费用，降低术后疼痛不适的发生率，改善疗效，是一安全有效的方法，具有推广价值。