C. J. Krones

Incisional Hernia: Open Techniques

Even with the routine use of mesh, repairing an incisional hernia is a challenge. Increasing evidence of impaired wound healing in these patients supports routine use of an open prefascial, retromuscular mesh repair. Basic pathophysiologic principles dictate that for a successful long-term outcome and prevention of recurrence a wide overlap underneath healthy tissue is required. The extent of this overlap should be 5 cm in all directions: surrounding the wound closure, subxiphoidal underneath the ribs, below the arcuate line, and retropubic.

Influence of polyglecaprone 25 (Monocryl) supplementation on the biocompatibility of a polypropylene mesh for hernia repair

Background: Supplementary polyglecaprone 25 (Monocryl) monofilaments were added to a lightweight pure monofilament polypropylene mesh (PP mesh) to improve intraoperative handling (PP+M mesh). This study was designed to evaluate the influence of this additional supplementation on the biocompatibility in a rodent animal model.Methods: Two mesh materials, a composite mesh (PP+M) and the pure polypropylene variant (PP), were compared after subcutaneous implantation in a standardized rat model. Histological analysis of the inflammatory response was performed after 28, 56 and 84 days of implantation. Material absorption, inflammatory tissue reaction, fibrosis and granuloma formation were investigated, as well as the percentage of proliferating and apoptotic cells at the interface.Results: Both mesh materials showed a slight foreign body reaction involving mainly macrophages and foreign body giant cells. Total absorption of the Monocryl filaments of the PP+M mesh occurred between 56 and 84 days of implantation. Both the inflammatory and the fibrotic reaction were decreased (n.s.) in the PP+M mesh group compared to the pure PP mesh. Whereas the percentage of proliferating cells showed no significant difference, the rate of apoptotic cells was significantly decreased in the PP+M mesh group over the whole implantation period.Conclusion: Compared to the pure polypropylene mesh, our data confirm that the use of a polypropylene mesh supplemented with absorbable Monocryl filaments is feasible without additional short-term mesh-related complications in the experimental model or negative side effects on biocompatibility.

The rare epidemiologic coincidence of diverticular disease and advanced colonic neoplasia

Background and aimsIn Western industrialised countries the prevalence of neoplastic colonic lesions and diverticular disease markedly increases with age. In contrast, the coincident occurrence of both diseases seems to fall below their individual epidemiologic estimates. Because directly comparing data are rare, this retrospective study evaluates the coincidence of neoplastic lesions and diverticular disease.Patient and methodsA total of 1,838 patients from 1986 to 2000 were admitted to the study. For 1,326 patients—56% male (n=741), 44% female (n=585), mean age 64 (±11.83 SD)—with a resection due to colonic cancer, the documented findings of colonoscopy, colonic contrast enema, and/or histopathology were analysed with regard to the prevalence of colonic diverticulosis. In 512 patients—51% male (n=263), 49% female (n=249), mean age 60 (±12.59 SD)—with a colonic resection due to diverticulitis, the synchronous or metachronous occurrence of neoplastic colonic lesions was recorded using the database of the Tumour Centre, Aachen. To compare the observed results with published epidemiology, statistical analysis included age-referred binomial tests and an age-stratified analysis (Cochran–Mantel–Haenszel test). Odds ratios (OR) were also calculated. P<0.05 was considered to indicate locally statistical significance.ResultsIn the cancer group, we found a statistically significant reduced rate of diverticula in nearly all age categories and the age-stratified analyses (corresponding OR 0.30–0.51). Consistently, the diverticulitis group revealed a statistically significant decreased rate of advanced colonic neoplastic lesion in nearly all age categories and all age-stratified analyses (corresponding OR 0.13–0.43).ConclusionOur results indicate that patients with colonic neoplastic lesions or diverticular disease probably form heterogeneous groups. Because current results from molecular biology emphasize the impact of the extracellular matrix on the genesis of diverticulosis and colonic cancer, the observed heterogeneity could be an expression of a distinct composition of the local milieu.

Incisional hernia: challenge of re-operations after mesh repair

Background and aimsThe widespread use of meshes for the repair of incisional hernia is currently followed by an increasing number of re-operations. The incidence of incisional hernia recurrence after mesh repair varies between 3 and 32%. The problem of mesh failure and options for another surgical intervention seem rather unattended.MethodsWe present our experience of 77 re-operations after previous mesh repair that were performed between 1995 and 2004 out of a total of 1,070 operations for incisional hernia. The retrospective analysis focused on recurrence in relation to location, material of the previous mesh repair and the surgical procedure to resolve the problem.ResultsThe locations of the preceding meshes were epifascial as onlays (n=23), retromuscular as sublays (n=46), within the defect as inlays (n=6) or intraperitoneally (n=2). The direction of the incision was vertical medial (n=41) or horizontal crossing the linea semilunaris (n=36). Recurrences after median incisional hernia mesh repair mainly occurred at the cranial border of the mesh subxiphoidal. Except for two patients, all recurrences manifested at the margin of the enclosed mesh.ConclusionsRe-operation after previous mesh repair is a surgical challenge. The type of revision procedure has to consider the position and material of the previous mesh. In our clinic recurrences, heavyweight polypropylene meshes were mostly treated with mesh exchange and lightweight polypropylene meshes could be treated by extension with a second mesh. In contrast to suture techniques, deficient mesh repairs are more evidently related to technical problems.

Deleterious Effect of Zinc in a Pig Model of Acute Endotoxemia

By antiapoptotic effects and the induction of the heat-shock response, zinc is supposed to be a promising means of therapy during sepsis. As zinc also stimulates the expression of proinflammatory cytokines, its administration during the proinflammatory stage of septic shock might have adverse effects. Therefore, this study analyzes the influence of zinc during the acute phase of endotoxemia. In a pig model of acute endotoxemia, animals were divided into two groups: group I (n = 5) with saline treatment and group II (n = 5) with zinc treatment in close succession to lipopolysaccharide (LPS) (1.0 μ g/kg Escherichia coli endotoxin WO 111:B4). Hemodynamic and pulmonary monitoring was followed by combined reflection photometry, pulse oxymetry, blood gas samples, and temperature measurement. Plasma concentrations of tumor necrosis factor (TNF)α and interleukin (IL)-6 were analyzed by enzyme-linked immunosorbent assay (ELISA). Morphology included the weight of the lungs, the width of the alveolar septae, and the paracentral necrosis rate of the liver. After LPS infusion, group II (zinc) showed an impressive and significant deterioration of all pulmonary and most of the hemodynamical parameters compared to group I (saline). Levels of TNFα and IL-6 measured were significantly higher after zinc treatment. In accordance, we found significant more morphologic damages in group II (zinc). The almost simultaneous infusion of zinc and LPS complementary induced proinflammatory effects with a deleterious outcome. The same potentials characterizing zinc as a promising tool of prophylactic therapy in sepsis seem to ban its use during the acute phase.

The Influence of Inguinal Mesh Repair on the Spermatic Cord: A Pilot Study in the Rabbit

The permanent implantation of a polypropylene mesh during inguinal hernia repair causes chronic inflammatory changes in the surrounding tissue. We investigated the effect of this foreign body reaction on the structures of the spermatic cord in the rabbit. Eight Chinchilla rabbits underwent unilateral inguinal hernia repair by the Lichtenstein technique using Marlex (n = 4) orUltrapro (n = 4) mesh. The contralateral side was operated upon using the Shouldice repair. Three animals served as controls. Three months after operation we analyzed testicular size, testicular temperature, and arterial perfusion by excitation light of a 780-nm laser after injection of 0.5 mg/kg indocyanin green. Histological evaluation included spermatogenesis (Johnsen score) and foreign-body reaction. Testicular volume increased about 10% after each operation. The decrease of arterial perfusion and testicular temperature was more significant after mesh repair than following Shouldice operation. After mesh implantation we found fewer seminiferous tubules classified as Johnsen 10 (Marlex: 51.3%, Ultrapro: 45.0%) than after Shouldice repair (63.8%) or in the controls (65.8%). The spermatic cord showed a typical foreign-body reaction at the interface between mesh and surrounding tissue, which was not detectable after Shouldice repair. Preserved cremasteric muscle fibers protected the structures of the spermatic cord. The inflammatory foreign-body reaction of the surrounding tissue induced by the inguinal prosthetic mesh includes the structures of the spermatic cord. This may have an influence also on spermatogenesis. Therefore, we recommend strict indications for implantation of a prosthetic mesh during inguinal hernia repair.

Zinc deficiency impairs wound healing of colon anastomosis in rats

BackgroundAnastomotic leakage is a relevant surgical complication. The aim of the study was to investigate the influence of a controlled preoperative zinc deficiency on the extracellular matrix composition of colon anastomosis.Materials and methodsForty male Wistar rats were randomized to either a zinc deficiency group (n = 20) or a control group (n = 20). In each animal, a transverse colonic end-to-end anastomosis was performed. On postoperative day 7, the surface of the mucosal villi, expression of matrix metalloproteinases (MMP) 2, 8, 9, and 13, and both the number of proliferating cells (Ki67) and apoptotic cells, as well as the collagen types I/III ratio were analyzed. Within the anastomotic area the mesenterial region and the antimesenterial region were analyzed separately.ResultsIn each group, one anastomotic leakage was detected. Expression of both MMP 2, 9, and 13 was significantly higher, and expression of Ki67 was significantly reduced in the zinc deficient group both mesenterial and antimesenterial. The collagen types I/III ratio was reduced in the zinc deficiency group by trend, without statistical significance neither mesenterial nor antimesenterial. Likewise, zinc deficiency affected neither the expression of MMP 8 nor the rate of apoptotic cells, respectively. Analyses of the surface of the mucosal villi revealed no significant differences comparing the groups with neither mesenterial nor antimesenterial.ConclusionsOur study constitutes the known negative effect of zinc deficiency on wound healing. Zinc deficiency significantly increased the activity of MMPs (2, 9, and 13), caused a reduced collagen type I/III ratio, and delayed cell proliferation and quality of intestinal wound healing.

Different matrix micro-environments in colon cancer and diverticular disease

Background and aimsThe extracellular matrix and the interactive signalling between its components are thought to play a pivotal role for tumour development and metastasis formation. An altered matrix composition as potential underlying pathology for the development of colorectal cancer was hypothesized.MethodsIn a retrospective study of patients with colon cancer, the extracellular matrix in tumour-free bowel specimen was investigated in comparison with non-infected bowel specimen from patients operated on for colonic diverticulosis. The following matrix parameters with known associations to tumour formation, cell proliferation, invasion and metastasis were analysed by immunohistochemistry and quantified by a scoring system: VEGF, TGF-β, ESDN, CD117, c-erb-2, cyclin D1, p53, p27, COX-2, YB-1, collagen I/III, MMP-13, PAI and uPAR. Expression profiles and correlations were calculated.ResultsThe comparison of the two groups revealed a significantly decreased immunostaining for CD117 and TGF-β in the cancer group (8.5±2.6 vs 10.3±2,1 and 4.9±1.5 vs 8.1±3, respectively), whereas PAI scores were significantly higher than in patients with diverticular disease (8.1±1.6 vs 6.2±0.9). Overall correlation patterns of matrix parameters indicated pronounced differences between tumour-free tissue in cancer patients compared with patients with diverticular disease.ConclusionsOur results indicate distinct differences in the colonic tissue architecture between cancer patients and patients with diverticulitis that support the notion of an altered matrix composition predisposing to the development of colon cancer.

Collagen in colon disease

The pathophysiology of wound healing in the bowel wall suggests that collagen and matrix metalloproteinases (MMPs) have an important role in the changes of the bowel wall seen in several colonic diseases. Several recent studies suggest that disturbances of the collagen texture and the extracellular matrix (ECM) metabolism are major factors leading to the onset of diverticular disease. Changes of the ECM also play a role in the development of inflammatory bowel diseases. Regarding the permanent remodeling of the bowel wall, any imbalance of the ECM could support the onset of chronic inflammation and the development of fistula formation, such as that seen in patients with Crohn’s disease. Disturbances of the ECM play a role in the pathogenesis of anastomotic leakage after large bowel surgery and suggest the presence of a genetically defined risk population with disturbed wound healing mechanisms. This concept could explain the well known situation where an anastomotic breakdown is observed, despite the absence of other known risk factors and after a technically correct anastomosis.

Mesh reconstruction preventing sacral herniation

Sacral hernias are uncommon defects developing through the pelvic floor after partial or total sacrectomy. We report on a 29-year-old woman, who has been under our care with a cystic formation after perineosacral resection of a rhabdomyosarcoma and partial sacrectomy. The cystic tumor was resected and a mesh repair performed to prevent sacral herniation. The current literature is summarized; etiology and management recommendations of this rare complication are discussed.