Evaluating the in vitro adhesive strength of biomaterials. Biosimulator for selective leak closure.

AIMS: Surgical measures always involve problems of hemostasis and tissue management. Tissue sealing can be carried out in this case, with knowledge of the adhesive strength of liquid and fleece-bound sealing being of great clinical relevance. By employing a leak closure model, it has been possible to perform in vitro standardized technological-biomechanical experiments on a biomembrane mounted in a pressure chamber (biosimulator). FINDINGS: Liquid sealing (fibrin gluing: 4.1 hPa, photopolymerisate: 82.9 hPa) offers minimal and maximal adhesive strengths. Fleece-bound sealing does not depend on the carrier material and is always more stabile than pure liquid sealing, whereby systems that must be coated "on the spot" (prepare-to-use: 22.3-25.3 hPa) exhibit significantly lower adhesive strength (p < 0.0001) than a biodegradable collagen system, which is ready-to-use thanks to its fibrinogen-based coating (TachoComb H). Practicability, effectiveness and efficiency are further advantages of ready-to-use systems. CONCLUSIONS: The biosimulator, presented here, is flexible in terms of its application for tissue management and it enables reproducible, economic and ecological evaluation of repair systems, e.g. tissue sealings.

Aesthetic and functional correction of female, asymmetric funnel chest - a combined approach.

There is still sparse information published about the surgical correction of female funnel chest deformity. Women with severe asymmetric funnel chest deformity often present with asymmetric, hypoplastic breasts. These patients frequently complain of physiological limitations in connection with gross aesthetic impairment. To correct these two features a combined approach is presented in this study. 10 women were operated with correction of the thoracic wall deformity by open retrosternal mobilisation and metal plate fixation. Either during the same procedure or in a secondary operation, submuscular breast augmentation was performed to correct breast hypoplasia and asymmetry. All patients tolerated the operation very well without any complications. Aesthetic outcome was rated good to excellent in secondary breast augmentation, whereas simultaneous implant positioning was prone to cause symmastia. In conclusion we recommend correction of female asymmetric funnel chest by primary sternal reduction with secondary breast augmentation during metal plate removal 1 year after.

Gastroschisis and omphalocele: treatments and long-term outcomes.

Between February 1994 and April 2004, we treated 40 children with gastroschisis and 26 children with omphalocele. We recorded the course of pregnancy, pre- and post-natal complications, delivery, operation, post-operative therapy, and long-term outcomes. Additionally, we conducted follow-up examinations of 37 of these 66 children (56%). We analysed their abdominal musculature, development, cosmetic result and quality of life. The median duration of follow-up was 6.3 years (range 1-10). In 35/40 children (88%) with gastroschisis and in 18/26 children (69%) with omphalocele, there had been prenatal diagnosis. The average maternal age of 23.9 years in the gastroschisis group was lower than in the omphalocele group (29.9 years). Delivery was by caesarean section in 93% of the gastroschisis group and 65% of the omphalocele group. Outcomes following vaginal delivery were no worse than those after caesarean section. Further, congenital abnormalities were shown in 28% of gastroschisis cases, and were limited to the gastrointestinal tract. Of the omphalocele cases 81% showed further abnormalities. Direct closure of the abdominal wall defect was possible in 31/40 (78%) of the gastroschisis cases and 15/26 (58%) of the omphalocele cases. Mortality in gastroschisis was nil; two children with omphalocele died (8%). Outcomes were better after primary closure than in stepwise reconstruction. Follow-up showed good results in all categories. Developmental delays were rapidly made up after treatment, and 75% of the children had no gastrointestinal problems, or suffered from these rarely. Almost all the children were of normal weight and height, and physical and intellectual development were delayed in only one third of the children. The surgical scar was rated as good or very good in about 80% of the cases. Except for those with severe defects, the children had good ratings for quality of life. Improvements in short-term results of gastroschisis and omphalocele treatment can be attributed to recent developments in prenatal diagnosis and the advancements of centralised perinatal care. Our long-term results clearly demonstrate that initial gastrointestinal problems and developmental delays were made up during the first two years of life. Prenatal counselling can now be more optimistic.

Forces to be overcome in correction of pectus excavatum.

OBJECTIVE: The Erlangen technique of funnel chest correction is carried out through an anterior incision, and an essential step is retrosternal mobilization. After elevation of the funnel, the chest wall is stabilized with a lightweight transsternal metal implant. Forces necessary to elevate the chest wall were measured at defined intervals during the operation to prospectively assess the effect of peristernal and retrosternal dissection. METHODS: Over a 3-year period, systematic tension measurements were carried out on 100 consecutive patients with symmetric funnel chest to assess the effect of individual steps in mobilization of the sternum. RESULTS: Whereas in adolescents the extraction force is about 175 N, in adults it is not possible to elevate the sternum to the desired level without surgical mobilization because the force required is, on average, more than 200 N. Only about 50% of this tension can be eliminated by costal chondrotomy. To reduce the tension further and achieve a stable result without the need for heavy-duty internal fixation, we carry out a retrosternal dissection, including removal of the slips of the diaphragm and the insertions of the transversus thoracis muscle. The mean tension at the end of the procedure is 25 N. CONCLUSIONS: Our measurements show that retrosternal dissection is the decisive step in the Erlangen technique, which might explain the low relapse rate and allow for a less extensive anterolateral mobilization.