We conclude that spider silk is a viable guiding material for Schwann cell migration and proliferation as well as for axonal re-growth in a long-distance model for peripheral nerve regeneration.

No abstract

Defects of peripheral nerves still represent a challenge for surgical nerve reconstruction. Recent studies concentrated on replacement by artificial nerve conduits from different synthetic or biological materials. In our study, we describe for the first time the use of spider silk fibres as a new material in nerve tissue engineering. Schwann cells (SC) were cultivated on spider silk fibres. Cells adhered quickly on the fibres compared to polydioxanone monofilaments (PDS). SC survival and proliferation was normal in Live/Dead assays. The silk fibres were ensheathed completely with cells. We developed composite nerve grafts of acellularized veins, spider silk fibres and SC diluted in matrigel. These artificial nerve grafts could be cultivated in vitro for one week. Histological analysis showed that the cells were vital and formed distinct columns along the silk fibres. In conclusion, our results show that artificial nerve grafts can be constructed successfully from spider silk, acellularized veins and SC mixed with matrigel.

The existence of a pathogenic link between blunt soft tissue trauma and the formation of post-traumatic lipomas is still controversial. Two potential mechanisms are discussed. Firstly, the formation of so-called post-traumatic 'pseudolipomas' may result from a prolapse of adipose tissue through fascia induced by direct impact. Alternatively, lipoma formation may be explained as a result of preadipocyte differentiation and proliferation mediated by cytokine release following soft tissue damage after blunt trauma and haematoma formation.

The pathogenetic link between soft tissue trauma and the formation of posttraumatic lipomas is still controversially discussed. There are 2 potential explanations to correlate soft tissue trauma and adipose tissue tumor growth. The first is the formation of so-called posttraumatic pseudolipomas by prolapsing adipose tissue through fascia resulting from direct impact. A second possibility points toward lipoma formation as a result of preadipocyte differentiation and proliferation mediated by cytokine release following soft tissue trauma and hematoma formation.

Temporary arteriovenous loops provide adequate recipient vessels and flow to supply microvascular free flap tissue transfer in areas lacking recipient vessels and in which no other reconstructive options exists. No statistical differences in complications and overall outcome were found between immediate or secondary free tissue transfer. Meticulous monitoring of microvascular perfusion, however, is mandatory in both approaches and early intervention is necessary to ensure successful tissue transfer.

No abstract

Due to its function, anatomy, and exposition to multiple pathogens, the hand is highly susceptible to infection. Most of these infections are post-traumatic. Isolates of pathogens from infected hands contain mainly Staphylococcus aureus and beta-hemolytic group A streptococci. We find Pasteurella canis and P. multocida from cat and dog bite wounds and Eikenella corrodens from human bite wounds. The "fight-bite clenched fist" wound, with penetration of the metacarpophalangeal joint and its high risk of septic arthritis, has always to be suspected when patients present with human bites. The therapy of hand infection is based on three principles: surgical treatment, adequate antimicrobial therapy, and early physiotherapy. Early infectious conditions of the hand, e.g. cellulitis and early paronychia, may be treated without surgery. Antimicrobial treatment must be specific for the pathogen and its resistance to antimicrobial agents. Bite wounds should be treated with beta-lactam antibiotics and beta-lactamase inhibitors. Staphylococci and streptococci can be covered by first and second generation cephalosporins. The increasing resistance of staphylococci to antibiotics has to be taken into account. Infections with anaerobic and gas-producing bacteria are rare but occur predominantly in diabetics and immune-compromised individuals.