Biomedical subjects

J Conze

Publications and source records attributed to J Conze.

26 records · Page 2Linked to original sources

PubMed1998

Modified mesh for hernia repair that is adapted to the physiology of the abdominal wall.

OBJECTIVE: To develop a new mesh for hernia repair that is adapted to the physiological forces. DESIGN: Animal experiment. SETTING: Surgical Department of the RWTH-Aachen. ANIMALS: Wistar rats MAIN OUTCOME MEASURES: Textile analysis, tensile strength, bending stiffness, histology and morphometry. RESULTS: After textile analysis of commercially available meshes in clinical use we defined the physiological forces and constructed a new mesh (Soft Hernia Mesh, SHM) based on a combination of non-absorbable polypropylene and absorbable polyglactin 910. The amount of non-absorbable material could be reduced to < 30% compared with Marlex while still guaranteeing the necessary pulling force of 16 N/cm. Improvements of the hosiery structure improved the symmetrical distribution of the retaining forces in all directions. Compared with the considerable restriction of the abdominal wall mobility by Prolene (polypropylene) and Mersilene (polyester) meshes there was no increase in the bending stiffness after the implantation of the new mesh. Histological examination showed a pronounced reduction of the inflammatory reaction in the tissues, and the collagen bundles were orientated merely around the mesh filaments instead of forming a scar plate that completely embedded the mesh. CONCLUSION: Different meshes caused specific histological reactions with changes of their mechanical properties after implantation in rodents. A new mesh with a reduced amount of polypropylene showed both less inflammation and less restriction in the mobility of the abdominal wall though it exceeded the required tensile strength of 16 N/cm.

Abdominal Muscles↗

PubMed1997

[Value of subcutaneous drainage in repair of primary inguinal hernia. A prospective randomized study of 100 cases].

Following Shouldice repair of a primary inguinal hernia 50 patients were given subcutaneous Redon drains, while another 50 patients underwent operations without drains in a prospective randomized trial. The amount of postoperative wound secretion in the drainage bottle was added to fluid retention established by sonographic volumetric analysis. The degree of personal impairment was estimated by a visual analogue score. Inflammation parameters were recorded as well as the rate of complications. The drain group showed significantly increased fluid production in comparison to the group without drains on the 1st postoperative day (36.0 vs. 2.5 ml). Wound sepsis was found in two patients in the drain group. Seven patients with drains and eight patients without underwent percutaneous seroma puncture. The drain only slightly affected personal impairment (25.6% vs 21.4%, visual analogue score). Body temperature was elevated in the drain group on the 3rd day after operation (37.2 vs. 36.7 degrees C). We believe there is no indication for the routine use of a Redon drain in the repair of a primary inguinal hernia. Instead, percutaneous puncture of subcutaneous fluid retentions should be performed.

Adolescent↗

PubMed1997

[Morphologic correlation of functional abdominal wall mechanics after mesh implantation].

Modern surgical hernia repair depends increasingly on synthetic meshes for reconstruction of the abdominal wall. Despite the undisputed advantages of the synthetic meshes currently available, reports of late complications after implantation are accumulating. It is essential that the synthetic meshes be improved, but this makes a standardized animal model necessary for evaluation of their biocompatibility on both functional and morphological levels. In the present study, commercially available polypropylene and polyester meshes were implanted in a rat model, and detailed morphological and morphometric analysis were carried out. Correlations between the morphological and morphometric data and the function of the artificial abdominal wall were then sought. In summary, the data show that the mesh construction currently available are oversized and definitely restrict the function of the artificial abdominal wall. The degree of inflammation and fibrosis, the pattern of fibrosis, and the composition of the extracellular matrix exert decisive influences on the function. Fibrosis and inflammation are caused less by the material itself, however, than by its density, the way it is processed, and its surface. Future, that is to say second-generated, mesh constructions should be designed with the aims of reducing the amount of material used and finding material-specific processing methods in mind, to improve the functionally and morphologically defined biocompatibility.

Abdominal Muscles↗

PubMed1996

[Progressive pneumoperitoneum in treatment of inguinal and scar hernias. Results of animal experiments and clinical applications].

Preoperative progressive pneumoperitoneum is a well-known, but sporadically used procedure in preparing patients with giant inguinal or incisional hernias for the operation. The technique requires frequent insufflation of air into the abdominal cavity in order to create space to accommodate herniated viscera and facilitate fascial repair with minimal tension. This article demonstrates the histological findings, technique, complications, advantages and long-term results of the preoperative progressive pneumoperitoneum in hernia repair.

Abdominal Muscles↗

PubMed1996

[Changes in abdominal wall mechanics after mesh implantation. Experimental changes in mesh stability].

The use of biomaterials for incisional hernia markedly reduces the recurrence rates. Disadvantages are high rates of local wound complications and restriction of mobility by the rigid "shell". The abdominal wall mobility after mesh implantation is analysed for eight different mesh materials. The initial textile testing reveals relevant differences in structure with marked asymmetry in the different directions. The materials are implanted as inlay in rats for 3, 7, 14, 21 and 90 days. The deformation of the abdominal wall following intraabdominal pressure of 0-70 mmHg (0-9.81 kPa) is documented by 3D-photogrammetry, the tensile strength by tearing of excised strips of mesh. Three commercial available materials and two laboratory modifications lead independently of their textile characteristics to a marked restriction of the rounded configuration of the abdominal wall. The tensile strength exceeds by far the physiologically necessary value of 16 N/cm. Three newly developed meshes made of multifilament polypropylene with reduced amounts of material (21% and 28% relative to Marlex) lead to no restriction of the abdominal wall configuration yet have uncompromised stability. It might be possible to reduce the rate of local wound complications by the use of these newly developed meshes.

Abdominal Muscles↗

PubMed1996

[Preperitoneal mesh-plasty in incisional hernia repair. A comparative retrospective study of 272 operated incisional hernias].

In a retrospective study on 245 patients we evaluated the results of 272 incisional hernia repairs in the Department Surgery of the University Hospital Aachen. The group consisted of 58% male and 42% female patients with a mean age of 61.1 years and 111 primary and 161 recurrent incisional hernias. Conventional techniques (simple closure, Mayo) and alloplastic repairs were performed in 69.9 and 30.1%, respectively. During the last 4 years we predominantly used the preperitoneal mesh repair with polypropylene mesh (Marlex). The results of 87% of our group of patients were evaluated by questionnaire and information from the family physicians (mean follow-up period 64 months). The patients who underwent preperitoneal mesh repair were examined clinically and with ultrasound. In comparison to the results of conventional hernia repair, early complications (seroma, hematoma) were higher. The recurrence rate, however, was significantly lower in this group with mesh repair (6.8%) than in patients without alloplastic augmentation (32.6%). Whereas preperitoneal mesh repair is convincingly the ideal surgical technique, optimization of the alloplastic materials by reduction of the amount of foreign substance and improvement of elasticity and biocompatibility is mandatory.

Adolescent↗

PubMed1996

[Pathophysiology of the abdominal wall].

The use of biomaterials for closure of incisional hernias requires meshes adjusted to the physiological forces. The intraabdominal pressure is mainly influenced by the activity of the transverse muscles. The abdominal fascia of corpses withstands forces of 60-80 N/cm in horizontal and 20-30 N/cm in vertical direction; tearing of sutures occurs below 30 N/cm in horizontal direction. Assuming the abdominal cavity to be a thin hollow sphere, the rupture forces are approximately 4-16 N/cm for a diameter of 8-3 cm. The meshes currently in use are much stronger than this, rupturing at 40-100 N/cm. The curvature of the abdominal surface can be measured by 3D-photogrammetry and is highly significantly reduced following mesh implantation (t-test, 2-sided, P < 0.01). Reduction of the mesh material can decrease the rate of local wound complications and the stiffness of the abdominal wall.

Abdominal Muscles↗

PubMed1996

[Palliative therapy of inoperable malignant occlusive jaundice--stent implantation or biliodigestive anastomosis].

For therapy of malignant jaundice different methods are possible: The palliative operative bypass and the monoperative stent implantation by endoscopic or transhepatic procedure. The primary success rate of both methods is similarly high (> 90%). The rate of early complication and the lethality of the stent implantation compared to the operative procedure are lower. The rate of occlusion and incidence of later cholangitis by operative bypass are lower. Postoperative lethality is related to the ASA classification. The preoperative diagnosis of resectability by CT, NMR, angiography and diagnostic laparoscopy has a success rate of maximally 95%. The choice of therapeutic method is therefore related to the general condition of the patient (ASA, staging, duodenal stenosis, expected survival time).

Anastomosis, Surgical↗