Repair Of Abdominal Wall Defects Research Articles

Laparoscopic Prosthetic Reinforcement of Hiatal Herniorrhaphy

Background/Aims: Primary repair of a large hiatal hernia is associated with a published recurrence rate of up to 10%; anecdotal rates even higher than this have been reported to the authors. The use of prosthetic material in the repair of other abdominal wall defects has often produced better results than primary repair. We wanted to compare laparoscopic primary repair of large hiatus hernias with laparoscopic primary repair reinforced with prosthetic. Methods: Thirty-one patients with symptomatic gastroesophageal reflux and a hiatal defect 8 cm or greater were randomized to Nissen fundoplication with posterior cruroplasty (n = 16) or Nissen cruroplasty, and onlay of polytetrafluoroethylene (PTFE) mesh (n = 15). All patients underwent preoperative esophagogastroduodenoscopy (EGD) and barium esophagography. After posterior cruroplasty with interrupted nonabsorbable suture, the mesh reinforcement group had an onlay of PTFE placed around the hiatus. A radial slit with 3 cm ‘keyhole’ (to accommodate the esophagus) was cut into the PTFE. The prosthetic was stapled to the diaphragm, and the two leaves of the slit were stapled to each other. All patients underwent EGD at 3 months and all had esophagrams every 6 months postoperatively. Follow-up ranged from 12 to 36 months. Results: Length of hospital stay was equal in both groups (2 days). The average cost to the patient with PTFE was USD 1,050 higher than to the patient with primary repair. There were 2 complications (1 pneumonia, 1 urinary retention) in the PTFE group, and 1 complication (pneumothorax) in the primary repair group. There were 3 recurrences (18.8%) in the primary group (p = 0.08, χ² test). Conclusion: The use of PFTE reinforcement for primary repair of large hiatal hernias may result in a lower rate of recurrent herniation compared to primary repair alone.

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.

Evaluation of a collagen-based biosynthetic material for the repair of abdominal wall defects.

A collagen tissue polymer composite manufactured in sheep and prepared in two different forms (wet and dry) was compared to polypropylene mesh and to a control group for effectiveness in the repair of an abdominal wall defect in a rabbit model. The wet and dry patches were shown to differ significantly in their pore size. The wet material was shown to retain its natural porosity and promoted neovascularization, tissue integration, cellular infiltration, and neomatrix formation compared to the dry collagen-polymer patch. This material was superior to the polypropylene mesh implant, which was associated with significant adhesions. The appearance of type VI collagen was the earliest sign of new cell infiltration and neomatrix formation within the implant. New deposition of type VI collagen was apparent throughout the thickness of the implant within 4 weeks, followed by type III collagen accumulation. Decreased porosity of the collagen component in the dry patches resulted in a totally nonintegrated implant. This induced a foreign-body capsule with minimal cellular tissue infiltration and no deposition of collagen types VI and III within the implant.

Comparison of Meshes for the Repair of Experimental Abdominal Wall Defects

The aim of this experimental study was to compare the effects of polytetrafluoroethylene patch, polypropylene mesh, and porcine dermal collagen implant in rats for the repair of abdominal wall defects. We created experimental abdominal wall defects in 45 rats (three groups of fifteen) and repaired them with polytetrafluoroethylene, polypropylene mesh, and porcine dermal collagen implant by onlay technique. We sacrificed 4 rats from each group at 4, 8, 10, and 12 weeks after implantation and observed if hernia, adhesion, effusion, or infection occurred. We measured the tensile strengths of meshes by a digital tensometer. We made histological and electron microscopic evaluations of the meshes. Postoperative infection and effusion occurred in one rat in each group. Hernia was not found throughout the trial. The tensile strength of polytetrafluoroethylene patch and polypropylene mesh increased more than porcine dermal collagen implant until the end of week 12. Adhesion formation was minimal in the porcine dermal collagen group and moderate in the polytetrafluoroethylene patch and polypropylene mesh groups. Polytetrafluoroethylene patch showed minimum absorption and maximum foreign body reaction. Our results show that although none of the material reached the criteria of ideal mesh, polypropylene mesh is the better mesh for the repair of abdominal defects. Polytetrafluoroethylene patch though expensive, can also be used as a reliable mesh. We do not advise porcine dermal collagen implant as a mesh for abdominal defects due to its weak structure.

Organ culture in 3-dimensional matrix: in vitro model for evaluating biological compliance of synthetic meshes for abdominal wall repair.

A new in vitro method to evaluate the early critical interactions between synthetic prosthetic materials and growing tissues is reported. The correct spatial organization and proper cell to cell interaction required to mimic the in vivo environment was obtained in a 3-dimensional (3-D) embryo organ culture. The clot formed by plasma and chick-embryo extract provided a natural 3-D extracellular matrix that was able to support the growth and differentiation of intestinal tissue dissected from 12-day-old chick embryos. Different materials used for the repair of abdominal wall defects were taken as standards; all the prosthetic materials were devoid of any evident cytotoxic potential over a 10-day culture period, so they did not interfere with the organogenesis process. A polyglactin mesh (Vicryl) was fully incorporated into the growing tissue, but early signs of its degradation were detectable. The biologically inert materials polyethylene terephthalate (Mersilene) and polypropylene (Marlex, Prolene, and Herniamesh) retained their structural integrity when incubated with cultured tissue at 37 degrees C, and they did not hinder cellular proliferation or fibroblast migration. However, the outgrowth behavior was very different while the connective tissue invaded the interstices of the polyethylene terephthalate mesh; the explants and the migrating cells were repelled by hydrophobic polypropylene meshes. These findings are in agreement with other reported results in in vivo studies. Therefore, this method can be considered as reliable and predictable for the evaluation of biopolymers.

A new technique of repair for small abdominal wall defects

SummaryUmbilical, epigastric and incisional hernias may cause incarceration and strangulation of the intra-abdominal organs. When ≥ 10 mm trocars are used, incisional herniation may occur if fascial sutures have not been used. We present a new instrument and a new method for the secure repair of small abdominal wall defects. The prototype has been produced by local steel workers.

Comparison of Novel Synthetic Materials with Traditional Methods to Repair Exposed Abdominal Wall Fascial Defects

Repair of large abdominal wall defects is a challenge, particularly when full-thickness tissue loss prohibits coverage of the fascial repair. Two novel synthetic materials (TMS-1 and TMS-2) have been shown to be better accepted than expanded polytetrafluoroethylene (Gore-Tex), and polypropylene (Marlex) in the closure of clean and contaminated fascia1 wounds that are immediately covered by skidsoft tissue. Therefore, 1-cm2 abdominal wall defects were created in each of the four quadrants of rat groups. Gore-Tex, Marlex, and TMS-1 or TMS-2 were used to repair three defects, the fourth being primarily closed. To ensure that each repair remained exposed, skin edges were sutured to underlying muscle. Additional animal groups underwent the same protocol; however, peritonitis was induced at surgery using a fecal inoculum technique. Animals were sacrificed 2 weeks later, at which time a blinded observer assessed the surface area and severity of adhesions. In clean wounds, the surface area of formed adhesions was less (p <. 004) after primary closure than each synthetic material; among the synthetics, TMS-2 caused significantly (p c. 01) less extensive adhesions than Marlex. In addition, the severity of adhesions to TMS-2 was comparable to that of defects closed primarily, and less severe (p <. 02) than those formed to Gore-Tex and Marlex. In animals with peritonitis, primary closure caused less extensive (p <. 03) adhesions than Marlex and Gore-Tex and significantly (p <. 002) less severe adhesions than Marlex, Gore-Tex, and TMS-2. However, the severity of adhesions formed to TMS-1 repairs proved comparable to primarily closed wounds. These experiments reaffirm the tenet that, whenever possible, abdominal wounds should undergo primary fascial closure. When soft tissue coverage over the repair cannot be achieved, TMS-2 is well tolerated in clean wounds. However, the superiority of TMS-1 over the other synthetic materials in contaminated wounds suggests it may also ultimately prove to be of clinical utility.

The sheath of the rectus abdominis muscle: an anatomical and biomechanical study

The anterior layer of the sheath of the rectus muscles is often used in the repair of incisional hernias through the linea alba. This practice has led us to undertake an anatomical and biomechanical study of its structure. Thirty fresh cadavers were divided into three groups of ten. All were dissected and biomechanical tests were carried out on the latter two groups: in Group 2 a dynamometer was used to measure the resistance to linear traction and to deformation. In Group 3 a bursting strength tester was used in order to determine the resistance to pressure. Morphological studies included measurements of the mean dimensions of the sheath, and of its composition at different levels. The biomechanical results show that the anterior sheath is more resistan to traction below the arcuate line than above it, whereas the resistance to pressure shows an opposite pattern. The resistance to traction of the posterior sheath is similar in its aponeurotic portion both above and below the umbilicus, the resistance to pressure being slightly less in the region of the arcuate line. The figures for deformation are essentially the same at all levels. The implications of these results for the repair of abdominal wall defects are discussed.

Dynamic and functional abdominal wall stabilization, reconstruction of extensive abdominal wall defects

The aim of any abdominal wall reconstruction is maximal functional stability and adequate soft tissue coverage. The anatomy, elevation and clinical application of the myofascial tensor fasciae latae transposition flap and of the microvascular musculocutaneous latissimus dorsi free flap are presented. Repairing extensive fascial defects and recurrent hernias with the tensor fasciae latae transposition flap provides strong, dynamic, and functional reconstruction of fascial continuity to prevent a further recurrence. Adequate functional and aesthetic repair of a full-thickness abdominal wall defect can be optimally managed by the innervated microsurgical latissimus dorsi free flap.

Modified Boerema technique for the closure of congenital abdominal wall defects to prevent incisional herniation and infection

Tension and infection often cause wound dehiscence or incisional herniation after the fascial closure of congenital abdominal wall defects in neonates. To overcome these problems, a modification of the Boerema technique (a method for repairing large incisional hernia in adults) was applied to repair abdominal wall defects in 14 neonates. The efficacy of this technique is discussed in this report.

Transdiaphragmatic pressure gradients and the lower esophageal sphincter after tight abdominal wall plication in the rat

Background: Gastroesophageal reflux (GER) is increasingly recognized as a complication of surgical closure of gastroschisis and omphalocele. Aim: This study tests the hypothesis that forceful abdominal wall closure reinforces the transdiaphragmatic pressure gradients that constitute the main GER-driving force and challenges the antireflux barrier. Materials and Methods: Abdominal and esophageal pressures as well as lower esophageal sphincter pressures (LESP) and length (LESL) were measured in 17 adult rats before tight abdominal wall plication, after it, and 1 week later. Results: This maneuver increased the transdiapragmatic expiratory gradient from 0.67 ± 1.31 to 6.97 ± 2.68 mm Hg ( P < .01) and the inspiratory gradient from 4.36 ± 1.13 to 10.79 ± 2.31 mm Hg ( P < .01) by markedly increasing both the expiratory (from 1.47 ± 0.74 to 9.44 ± 1.85 mm Hg; P < .01) and inspiratory (from 0.98 ± 0.69 to 6.83 ± 1.55 mm Hg; P < .01) intraabdominal pressures. These changes were transient, and all pressures became normal after 1 week. The antireflux barrier functioned properly under these new conditions because both LESP and the diaphragmatic pinch-cock pressure (DPP) increased, from 20.3 ± 3.63 to 26.5 ± 4.31 mm Hg ( P < .01) and from 16.4 ± 7.25 to 22.5 ± 4.36 mm Hg ( P < .01), respectively, while LESL remained unchanged. Conclusion: Tight abdominal wall plication in the rat generates high intraabdominal pressures and thus reinforces the transdiaphragmatic pressure gradients, but these conditions elicit a healthy barrier response with sphincteric reinforcement. In addition, these changes are transient and fade out some time after operation. These facts should be taken into account for understanding the pathogenesis of GER after repair of abdominal wall defects in human babies.

DEVELOPMENT OF A NOVEL SYNTHETIC MATERIAL TO CLOSE ABDOMINAL WALL DEFECTS

To compare the efficacy of a novel synthetic material (TMS-2) with polytetrafluoroethylene, polypropylene (Marlex), and primary closure of experimentally fashioned clean and contaminated abdominal wounds, 1-cm2 abdominal wall defects were created in each of the four abdominal quadrants of rats (n = 10). Patches of each material were used to repair three of these defects, the fourth being primarily closed. A second group of rats (n = 7) underwent the same operative protocol; however, peritonitis was induced at the time of surgery using a fecal inoculation technique. Animals were killed 2 weeks later, and surface area and severity of formed adhesions were assessed by a "blinded" observer. All closure techniques were successful insofar as none demonstrated fascial dehiscence. Compared with each synthetic material, the surface area of formed adhesions was smaller after primary closure in clean and in contaminated conditions; however, the three synthetic materials were equally matched regarding surface area of adhesions under both conditions. In the face of fecal contamination, TMS-2 proved identical to primary closure, each generating significantly (P < 0.02) milder adhesions than the other prosthetic materials. It is concluded that the TMS-2 may prove of clinical benefit to repair abdominal wall defects.

Improvement of the tissue integration of a new modified polytetrafluoroethylene prosthesis: Mycro Mesh ®

We studied the behaviour of the different tissue interfaces formed on a new type of prosthesis used for the repair of abdominal wall defects, Mycro Mesh ® (W. L. Gore and Ass., Flagstaff, AZ, USA), which consists of perforated layers of polytetrafluoroethylene (PTFE). In 20 New Zealand white rabbits, a full-thickness (except skin) 7 cm × 5 cm defect was created in the anterior abdominal wall. The defects were repaired with a prosthetic implant (Mycro Mesh ®) that was placed in direct contact with abdominal viscera and subcutaneous tissue. At 14, 30, 60 and 90 d post-implantation, samples were obtained from the tissue interfaces formed between the prosthesis and subcutaneous tissue, visceral peritoneum and receptor tissue, respectively. Samples were studied by optical microscopy and scanning electron microscopy. The immunohistological study was made with RAM-11, a monoclonal antibody specific for rabbit macrophages. Tensile strength was measured with an Instron tensiometer using 2 cm wide strips obtained parallel to the shorter axis of the implant. Strips included the prosthesis and two anchor zones on the receptor tissue. Macroscopically, the prosthesis induced little adhesion formation on the visceral peritoneum interface. Microscopically, an organized neoperitoneum and abundant tissue formed on the subcutaneous interface. In the prosthesis perforations, bridges of tissue linked the peritoneal and subcutaneous sides. The macrophage response decreased significantly in intensity between day 14 and day 90 (Student-Newman-Keuls test, P = 0.01). Tensile strength increased significantly (Wilcoxon test, P < 0.05) at every study period. To conclude: the Mycro Mesh ® prosthesis proved suitable for implantation in sites where it comes in contact with abdominal viscera and it provided good support for the formation of an organized neoperitoneum; the perforations in the prosthetic material improved implant integration; the macrophage response was not altered by the biomaterial and the tensile strength of the prosthesis increased as scar tissue formation and tissular integration of the prosthesis progressed.

Long-term results following repair of neonatal abdominal wall defects with Gore-Tex

Long-term results following repair of neonatal abdominal wall defects with Gore-Tex

Use of amniotic grafts in the repair of gastroschisis

This article describes the use of amniotic grafts (AG) in the repair of large abdominal wall defects in newborns with gastroschisis. From 1988 to 1995, 22 newborns with gastroschisis underwent surgical repair. In 12 primary closure (PC) was performed; in 10 the abdominal wall defect was covered with an AG. A double layer of AG was used and the graft was additionally covered with a silastic silo in 8 cases. The overall mortality was 14%; 3 children died from necrotizing enterocolitis or sepsis after AG. However, the difference in mortality of newborns with PC versus AG was not statistically significant. Patient characteristics, the postoperative courses, nd the frequency of complications were similar after PC and AG. It is concluded that AG has no negative impact on the postoperative course and yields a low overall mortality. In our opinion there are several advantages in using the AG technique: it is an autoplastic material that is readily available without costs, reefing and removal is unnecessary, and there is a potentially low rate of adhesions.

Intraoperative vascular assessment for estimation of risk in primary closure of omphalocele and gastroschisis

Surgical repair of anterior abdominal wall defects is often complicated by a discrepancy between the eviscerated organs and the intra-abdominal space available. Primary closure of the abdominal wall may result in increased intra-abdominal pressure and consecutive circulatory impairment. We report the results of a retrospective and consecutive prospective study evaluating the influence of different witameters on mortality and morbidity in children with gastroschitis and omphalocele. Both studies demonstrated that real-time sonographic investigations, intraoperative Doppler duplex sonography, and colour-coded Doppler sonography provide the oppurtunity to collect objective intraoperative data. Our data indicate that intraoperative vascular assessment facilitates the discrimination between infants who benefit from primary closure and those in whom a staged repair is the treatment of choice.

Experimental assay of a Dual Mesh ® polytetrafluoroethylene prosthesis (non-porous on one side) in the repair of abdominal wall defects

The porosity of the prosthetic biomaterials used to repair defects in the abdominal wall seems to influence the tissue repair process insofar as tissue integration of the prosthetic material and the formation of adhesions with abdominal viscera are concerned. We studied the behaviour of a new type of polytetrafluoroethylene prosthesis used for the repair of abdominal wall defects, Dual Mesh ® (DM), which has two different faces; one face has a porosity between 30 and 60 μm, while the other is nonporous. In 20 New Zealand White rabbits, a full-thickness (except skin) 7cm × 5cm defect was created in the anterior abdominal wall that was repaired with DM. At 14, 30, 60 and 90 days, samples were obtained and studied by light and scanning electron microscopy. An immunohistochemical study was made with antibody anti-rabbit macrophages (RAM-11). Tensile strength was measured with an Instron tensiometer using 2-cm-wide strips obtained parallel to the shorter axis of the implant. DM induced little tissue adhesion to the material on the visceral peritoneum interface and was surrounded by organized repair tissue. The biomaterial was integrated in the repair tissue on the subcutaneous interface, but not on the peritoneal interface. The macrophage response decreased between days 14 and 90 ( P < 0.001). Tensile strength increased significantly ( P < 0.05) at every study period. We conclude that the DM prosthesis has little tendency to formation of visceral adhesions, the DM prosthesis was well tolerated by the receptor organism and the tensile strength of the prosthesis/ receptor tissue interface increased with time.

Long-term results following repair of neonatal abdominal wall defects with gore-tex: P.M. Willis, C.T. Albanese, M.I. Rowe, et al. Pediatr Surg Int 10:93–96, (February), 1995

Long-term results following repair of neonatal abdominal wall defects with gore-tex: P.M. Willis, C.T. Albanese, M.I. Rowe, et al. Pediatr Surg Int 10:93–96, (February), 1995

Small Intestinal Submucosa

Prosthetic graft material is often used for the repair of abdominal wall defects that result from trauma, infection, neoplastic, or congenital deformities. A new material, porcine small intestinal submucosa, has been successfully used as an arterial and venous graft material in both canine and primate animal models with graft patency and infection rates equal to autologous vein. On the basis of these studies, small intestinal submucosa was used as a graft material for the repair of a 2 x 2-cm full-thickness defect of the muscle and fascia in the rodent abdominal wall (N = 11). Two animals were euthanized at 1 week, 2 weeks, 4 weeks, 2 months, and 3 months. At the time of euthanization, no abdominal hernias were noted and only minimal intra-abdominal adhesions were observed. One animal died on postoperative day 5 as a result of a wound dehiscence. Histological analysis of the excised abdominal wall hernia repairs revealed moderate initial inflammation but with incorporation of small intestinal submucosa with minimal inflammation at 2 months. No evidence of graft-versus-host rejection was noted with hematoxylin and eosin stains and light microscopy. Porcine small intestinal submucosa merits further study as a graft material for abdominal wall replacement.

Collagen-coated Vicryl mesh: A new bioprosthesis in pediatric surgical practice

Collagen-coated Vicryl mesh (C.C.V.M.) was used in 28 children who needed repair of thoracic and abdominal wall defects. Herein the authors report the clinical experience, surgical technique, and outcome in these cases.