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Biomedical subjects

U Klinge

Publications and source records attributed to U Klinge.

At least 73 records · Page 4Linked to original sources
PubMed2001

Influence of suture technique on laparotomy wound healing: an experimental study in the rat.

A suture length to wound length ratio (SLWL ratio) of 4:1 for laparotomy closure has proven in clinical studies to reduce incisional hernia incidence. The effect of different SLWL ratios on the mechanical qualities of the healing incision has not been examined experimentally. In 50 rats, the musculo-fascial layer of median laparotomies was closed with polypropylene sutures using SLWL ratios of 8:1, 4:1, 2:1 and 1.7:1. Single and running sutures, different tissue bites and different suture tensions were applied. Five rats served as controls. After 14 days, the horizontal strength of the incision was tested in a digitised tensiometer. The SLWL ratio, suture tension and suture technique proved to have significant influences on the mechanical strength of the incision. Running sutures and especially closures with a ratio of between 4:1 and 8:1 proved significantly stronger than wounds closed with single sutures. When small tissue bites were applied, the positive influence of running sutures was equalised in the early phase of wound healing. High suture tension led to significantly weaker scars independent of the applied suture technique. In accordance with clinical data, it could be proven experimentally that running closure of midline laparotomies with a SLWL ratio above 4:1 avoiding high suture tension exerts a significantly positive effect on the mechanical strength of the incision. Further studies are needed to allow measurement and better control of suture tension.

Animals↗
PubMed2001

Functional impairment and complaints following incisional hernia repair with different polypropylene meshes.

The influence of mesh material on the clinical outcome of hernia repair has often been neglected, although recent studies have clearly demonstrated the importance of mesh properties for integration in the abdominal wall. Of particular significance are the amount of mesh material and the pore size. In the following study, patients received different mesh types with distinct amounts of polypropylene and of various pore sizes for incisional hernia repair. We investigated whether the type of material influenced the clinical and functional outcomes. Between 1991 and 1999, 235 patients received polypropylene meshes in a sublay position for incisional hernia repair: 115 patients were implanted with a Marlex heavy-weight mesh (Mhw mesh), 37 patients with an Atrium heavy-weight mesh (Ahw mesh) and 83 with a Vypro low-weight mesh (Vlw mesh). The study protocol included ultrasound examination and 3D-stereography in all patients, with a total follow-up of 24 +/- 13 months (Mhw-mesh), 11 +/- 8 months (Ahw-mesh) and 8 +/- 7 months (Vlw-mesh). Our findings demonstrate that the side effects of mesh implantation, comprising paraesthesia and restriction of abdominal wall mobility, were significantly affected by the type of material implanted. Three-dimensional stereographic examinations were well in accordance with our clinical findings. Our data support the hypothesis that the use of low-weight large-pore meshes is advantageous for abdominal wall function.

Abdominal Muscles↗
PubMed2001

Elasticity of the anterior abdominal wall and impact for reparation of incisional hernias using mesh implants.

Mesh implantation to repair incisional hernia involves extensive disturbance of the integrity of the abdominal wall. To define the physiological requirements, we measured the elasticity of the abdominal wall of 14 anatomic samples. The complete abdominal wall was excised and stretched at a strain of 0-24 N in horizontal, vertical and oblique (upper and lower abdomen) directions. The resulting mean distension at 16 N was in the range between 11% and 32% for all directions. Furthermore, we found significant differences between tissue samples from male and female subjects, as well as considerable inter-individual differences in each group. Textile analysis of common mesh materials at 16 N showed elasticities in the range of 4%-16%. Comparing the textile characteristics with the physiological elasticity revealed inadequate properties in at least some of the mesh materials. Our findings indicate that the flexibility of the abdominal wall must be more or less restricted by extensive implantation of large meshes and recurrences may possibly be provoked at the margins of implanted materials.

Abdominal Muscles↗
PubMed2001

Functional assessment and tissue response of short- and long-term absorbable surgical meshes.

Within the last few years meshes have become essential for the temporary closure of the abdominal cavity to avoid the development of an intra-abdominal compartment syndrome. The interposition of a mesh as an inlay reduces the intra-abdominal pressure and improves markedly the blood circulation, particularly for the intestines and kidneys. Whereas non-absorbable meshes usually tend to produce fistulas in direct contact to the bowels, the interposition of short-term absorbable meshes result in large incisional hernias in almost all cases. In the following study we investigated the functional and histological consequences of a short-term absorbable mesh (polyglactin 910, Vicryl, loss of 50% of its mechanical stability within 3 weeks) and a long-term absorbable mesh (polylactide, LTS, preserved >50% of its mechanical stability for over 1 year). The mesh-modifications were both tested with the aid of three-dimensional stereography, tensiometry, light- (LM) and transmission electron microscopy (TEM) as well as morphometry after implantation intervals of 3, 7, 14, 21, 45, 90, 135 and 180 days in a standardised rat model. The PG-mesh initially revealed a pronounced inflammatory reaction and a significantly increased formation of connective tissue. The extensive arrangement of connective tissue in the interface mesh/recipient tissues correlated to an increased stiffness of the abdominal wall compared to the sham-group. However, a loss of mechanical stability and an increase of elasticity could be detected after 3 weeks of implantation which may be explained by the rapid absorption of the mesh material. In contrast to PG, the LTS-mesh indicated a decreased but persisting inflammatory reaction in the interface mesh-fibres/recipient tissues and a significantly reduced induction of connective tissue. Although, the formation of scar-tissue was diminished compared to PG the LTS-mesh preserved its mechanical stability after 180 days. The results indicate that the frequent development of incisional hernias with short-term absorbable meshes (PG) might be due to the decreased mechanical stability and dilatation of the newly formed connective tissue after 2-3 weeks. Moreover, extensive scar tissue development may promote adhesion formation. The implantation of the long-term absorbable LTS-mesh seems to be favourable with respect to its long-term mechanical stability and the decreased connective tissue formation.

Animals↗
PubMed2000

[Pathology of traditional surgical nets for hernia repair after long-term implantation in humans].

The widespread use of alloplastic materials as the standard procedure for hernia repair makes an evaluation of the long-term integration of these implants imperative. A total of 121 explanted meshes (mean implantation time 23.2 & 19.7 months) of polypropylene (Atrium((R)), n = 20; Marlex((R)), n = 50; Prolene((R)), n = 21), Polyester (Mersilene((R)), n = 19) and PTFE (Gore-Tex((R)), n = 11) were analyzed in regard to the tissue and cell response within the interface mesh-fiber/tissue. The mesh samples were investigated by light and electronmicroscopy, as well as immunohistochemistry. The morphometric results confirmed a persisting inflammatory proliferative foreign-body reaction with increased cell turnover in the recipient tissues. This reaction is mainly influenced by the selected mesh modification. The consequences of the arising "chronic wound" are discussed in detail, in particular with regard to possible malignant transformation.

Adult↗
PubMed2000

The repair of large parastomal hernias using a midline approach and a prosthetic mesh in the sublay position.

Parastomal herniation is a very frequent complication in enterostomy. The therapeutic strategy consists of three approaches: local fascial repair, relocation of the stoma, and a variety of more elaborate procedures, many of which also involve the use of nonabsorbable meshes. Despite this multitude of available techniques, recurrence rates are high, and long-term complications, especially after mesh implantation, are frequent. In order to improve operative results, we would suggest that a parastomal hernia be treated like a subtype of incisional herniation and that methods be employed that have proved to be effective in this situation. A midline approach allows the operation to be performed under practically sterile conditions. The reinforcing mesh is placed in a sublay position, using a combined intraperitoneal and epifascial preparation. Any direct contact between mesh and intestines is thus avoided. A new type of mesh with substantially reduced polypropylene content decreases the occurrence of both early and late complications.

Abdominal Muscles↗
PubMed2000

Expression of heat shock protein 70 (HSP70) at the interface of polymer-implants in vivo.

Synthetic polymer meshes are widely applied in the modern surgical approach for repairing abdominal wall defects. The implanted material is often observed leading to post-operative complications such as deficient abdominal wall mobility and adhesion formation with the abdominal cavity and/or abdominal organs. However, the functioning of the implant is primarily affected by the wound healing process guided by inflammatory events occurring at the tissue-material interface. This could presumably be influenced by the physicochemical properties of the polymer. With regard to it, the cellular and molecular processes involved in the successful restoration of the abdominal wall function are poorly understood. The present in vivo study, therefore, exemplary investigated in a rat model, the commercially available polymer-meshes Prolene (polypropylene, PP), Mersilene (polyester, PE) and Vicryl (polyglactin 910), as well as new mesh variants consisting either of PP (EB) or a combination of PP and polyglactin 910 (A plus or Vypro). The implanted material was evaluated by light and electron microscopy, immunohistochemistry as well as morphometry over an implantation period of 90 days. The data show that polymers induce heat shock protein (HSP)70, and its expression at the interface correlates inversely with the activity of the inflammatory reaction in vivo. Further, an ascent in HSP70 expression parallels the increasing implantation period and evolving foreign-body granulomas. Accordingly, a major role for HSP70 in modulating the local acceptance of polymers and as an additional marker for in vivo testing of polymers is suggestive.

Journal Article↗
PubMed2000

Abnormal collagen I to III distribution in the skin of patients with incisional hernia.

The surgical mesh-free repair of incisional hernias has to face recurrence rates of up to 50%. Apart from technical faults this is probably due to collagen metabolic disorders, known to play an important role in the development of inguinal hernia. In particular an altered ratio of collagen types I and III with an increase in collagen type III has been claimed to reduce the mechanical strength of connective tissues. Therefore, we investigated the content of collagen types I and III in the skin of patients with incisional hernia (n = 7) and recurrent incisional hernia (n = 5) in comparison to controls with healthy skin (n = 7) and normal skin scar (n = 7) both by immunohistochemistry and Western blot analysis. Both immunohistochemistry and Western blot analysis revealed a decrease in the ratio of collagen I/III due to a concomitant increase in collagen III. The patients with incisional hernias and with recurrent incisional hernias showed a ratio of 1.0 +/- 0.1 and 0.8 +/- 0.1, respectively, whereas the controls exhibit a ratio of 2.1 +/- 0.2 in healthy skin and of 1.2 +/- 0.2 in normal skin scar, respectively. The decrease was highly significant (p < 0.01) between the patients with either primary or recurrent hernia and the controls or the normal scar, as well as between controls and normal scar, whereas there was not any significant difference between primary and recurrent hernia (p > 0.05). Our data for the first time confirmed that the presence of incisional hernia is accompanied by impaired collagen synthesis in the skin. The decreased tensile strength of collagen type III may play a key role in the development of incisional hernias. Furthermore, it might explain the high recurrence rates of hernia repair by simple closure, as a repetition of the primarily failing technique, and the improvement by the additional use of alloplastic material.

Adult↗
PubMed2000

Influence of suture material and suture technique on collagen fibril diameters in midline laparotomies.

BACKGROUND: Although laparotomy closure is associated with a cumulative 15% failure rate, the effect of different suture techniques and materials on the ultrastructural composition of the healing incision has not been investigated. METHOD: in 40 Wistar rats the collagen fibril diameters and the regenerative tissue were compared using electron microscopy 14 and 28 days after midline laparotomy. Wounds were closed with single and running sutures using either polypropylene or polyglactin 910. RESULTS: Closure with polypropylene led to significantly larger mean fibril diameters than closure with polyglactin. Regardless of time and suture material, running closure resulted in significantly smaller mean collagen fibril diameters than single sutures. Four weeks after laparotomy, inflammatory reactions, disorganization of collagen and irregularities of the vascular architecture were found after closure with absorbable suture material but not after closure with nonabsorbable material. CONCLUSION: Suture material and suture method significantly influence the ultrastructural composition of the healing incision. Persisting mechanical irritation around the suture threads after single sutures and severe persisting inflammatory reactions after the use of absorbable suture material are important influencing factors.

Animals↗
PubMed1999

[Minimized polypropylene mesh for preperitoneal net plasty (PNP) of incisional hernias].

Repair of incisional hernias requires the extensive implantation of alloplastic materials. The extent of the scar tissue is markedly regulated by the amount and structure of the incorporated material and is responsible for the increased rate of local wound complications. Correspondingly, minimization of the alloplastic implants should be favorable. In a randomized, prospective clinical study, the early results were compared after implantation of either a minimized, low-weight (26.8 g/m2) mesh with a pore size of 5 mm or a common, heavy-weight (90.2 g/m2 polypropylene) mesh with a pore size of 0.8 mm. Indicators for clinical suitability were the rate and volume of seroma, subjective paraesthesia, physical capability, abdominal wall compliance, and the histologically analyzed tissue reaction of samples removed on the occasion of revision operations. As result, the optimized, low-weight mesh showed a remarkable decrease in the rate of seroma, patient complaints, less restriction of abdominal wall mobility, and improved abdominal wall compliance as verified by 3D stereography. These clinical findings corresponded to a pronounced decrease in inflammation and scar reaction, indicating improved incorporation of the alloplastic material. No other major complications except for one recurrence have been found.

Female↗
PubMed1999

Influence of polyglactin-coating on functional and morphological parameters of polypropylene-mesh modifications for abdominal wall repair.

Regarding oversized mechanical properties of most of the currently available materials a new mesh was developed (ETHICON, Norderstedt, Germany) and exactly adopted to the physiology of the human abdominal wall by reducing the amount of polypropylene (weight of <30 g/m2; mesh A). The consecutive increase of pores size as well as the use of multifilaments led to a pronounced increase of flexibility. To improve the handling during operation the initial stiffness of this low-weight large pores mesh was increased by strengthening with different amounts of absorbable polyglactin (combination of glycolide and lactide) in various forms: by coating (mesh B), adding multifilament polyglactin filaments (mesh C, Vypro) or both (mesh D), respectively. To test the consequences of the different supplementary techniques all mesh variants are implanted in a rat model. Over implantation intervals of 3, 7, 14, 21 and 90 days we measured the tensile strength, the resulting stiffness and surveyed the tissue response, particularly in regard to the extent of inflammation and to the induced fibrosis. The results proved a sufficient mechanical stability of the material reduced and pure polypropylene mesh A without restriction of the mobility of the abdominal wall compared with a group that had simple laparotomy and closure. The histological analysis of the interface showed a minor inflammatory reaction and a dense vascularisation. The addition of polyglactin multifilaments (mesh C) reduces the number of macrophages and granulocytes as indicators for acute inflammation, showing generally a scar formation limited merely to the perifilamentary region. The abdominal wall compliance remained unchanged compared with mesh A. The coating of the polypropylene with polyglactin (mesh B and D) appeared to change the tissue reaction remarkably, favouring the formation of a connective tissue capsule around the whole mesh. The mechanical testing revealed an apparent protrusion with an increase of curvature of the artificial abdominal wall at rising intraabdominal pressures. The entire coating of the polypropylene surface with polyglactin induces an all embedding scar plate, filling out the pores and forming a tissue capsule. The complex interaction of tissue and implanted biomaterials with their distinct alterations of the tissue response confirms the necessity of in vivo experiments even after 'minor' modifications. Whereas the addition of polyglactin filaments appears to be favourable, the coating of polypropylene with polyglactin seems to hinder the incorporation of the mesh.

Abdominal Muscles↗
PubMed1999

Foreign body reaction to meshes used for the repair of abdominal wall hernias.

OBJECTIVE: To investigate the local tissue reactions to meshes that had been removed from humans. DESIGN: Open study SETTING: Surgical department of the technical University, Aachen, Germany. MATERIAL: Samples of 17 non-absorbable meshes (1 polyester, 10 polypropylene, 2 reduced polypropylene, and 4 polytetrafluorethylene, PTFE) and 1 absorbable mesh (polyglactin 910) that had been implanted for repair of abdominal wall defects. INTERVENTIONS: Light and transmission electron microscopy, immunohistochemistry, and histological examination. MAIN OUTCOME MEASURES: Signs of inflammatory response. RESULTS: Light microscopy showed chronic inflammatory tissue reaction, even after years, with pronounced differences among materials. Partial volume of inflammatory cells (%) varied from 32 in polypropylene, to 12 in expanded PTFE, 8 in polyester, and 7 in reduced polypropylene. Formation of connective tissue correlated significantly with the extent of the inflammatory reaction (p<0.01). In meshes implanted for long periods there were still numerous macrophages at the interface between tissue and polypropylene (45%), polyester (45%), expanded PTFE (25%), and reduced polypropylene (22%). There was no difference in time dependent tissue reactions (p = 0.19). CONCLUSION: Inflammation around alloplastic materials used to repair defects in the abdominal wall persists for many years. There was evidence of long term wound complications as a result of persistent foreign body reactions. Further studies are required to evaluate the long term tissue response to these materials.

Abdominal Muscles↗
PubMed1999

Expression of the extracellular matrix proteins collagen I, collagen III and fibronectin and matrix metalloproteinase-1 and -13 in the skin of patients with inguinal hernia.

Although abnormal collagen metabolism has been ascribed an important role in the high recurrence rates after surgical hernia repair, knowledge on tissue sampled in the region affected by inguinal hernias is poor. In the present study, we determined collagen type I and type III in the skin of adult patients with indirect and direct inguinal hernias by both immunohistochemistry and Western blot analysis. In addition, we quantified the immunohistochemical expression of fibronectin and matrix metalloproteinase (MMP)-1 and -13. The results indicated that the ratio of collagen type I/III was significantly decreased in the skin of patients with either indirect (n = 9) or direct hernia (n = 7), with a concomitant increase in collagen type III (p < 0.001 vs. controls, n = 7, without affection of the inguinal region). There was no significant difference between patients with indirect and direct hernia (p > 0.05). MMP-13 was not expressed in any of the skin samples investigated, whereas MMP-1 was found in the epidermis. Fibronectin was predominantly detected at the epidermal-dermal junction. MMP-1, MMP-13 and fibronectin levels were significantly different between patients and controls (p > 0. 05). We conclude that in contrast to the unchanged expression of fibronectin and MMP-1 and MMP-13, the decreased ratios of collagen tpye I/III with the basically increased amount of collagen type III could be of significant importance for the pathophysiology of hernias. The specific ratio collagen I/III probably reflects the altered structural integrity and mechanical stability of the connective tissue in both indirect and direct hernias. Moreover, our findings stress that hernias should be regarded as the manifestation of a systemic disease in the inguinal region with a genetic background, explaining the high recurrence rates after repeated suture repair, as well as the usefulness of surgical meshes in this clinical setting.

Aged↗
PubMed1999

[Meshes within the abdominal wall].

The marked reduction in recurrence rates following reinforcement of the abdominal wall by meshes in incisional hernia has promoted their increasingly widespread use. The primary suture in technique failed more than half of the cases; therefore, the closure method needs to be changed and improved, particularly with regard to a possibly underlying defect in collagen metabolism. After more than 100 years of mesh development they are mainly placed in a sublay or onlay position, ePTFE, polyester and polypropylene are preferred. In any case the mesh has to overlap the defect sufficiently because of wound contraction. On the basis of our experience and reports in the literature, the advantages and disadvantages of various mesh techniques and mesh materials are discussed. However, because long-term studies are missing, the relevance of the cumulative risk for long-term complications such as mesh migration and fistula formation, the extent of patient complaints or the potential risk of a persistent foreign-body reaction cannot yet be ascertained. Nevertheless, because there are no surgical alternatives, meshes represent an improvement in hernia surgery that cannot be overestimated.

Follow-Up Studies↗