Muscle-in-vein conduit is successfully employed for repairing nerve injuries: the vein prevents muscle fiber dispersion, while the muscle prevents the vein collapse and creates a favorable environment for Schwann cell migration and axon regrowth. However, it requires microsurgical skills. In this study we show a simple strategy to improve the performance of a chitosan hollow tube by the introduction of fresh skeletal muscle fibers. The hypothesis is to overcome the technical issue of the muscle-in-vein preparation and to take advantage of fiber muscle properties to create an easy and effective conduit for nerve regeneration. Rat median nerve gaps were repaired with chitosan tubes filled with skeletal muscle fibers (muscle-in-tube graft), hollow chitosan tubes, or autologous nerve grafts. Our results demonstrate that the fresh skeletal muscle inside the conduit is an endogenous source of soluble Neuregulin 1, a key factor for Schwann cell survival and dedifferentiation, absent in the hollow tube during the early phase of regeneration. However, nerve regeneration assessed at late time point was similar to that obtained with the hollow tube. To conclude, the muscle-in-tube graft is surgically easy to perform and we suggest that it might be a promising strategy to repair longer nerve gap or for secondary nerve repair, situations in which Schwann cell atrophy is a limiting factor for recovery.
The reconstruction of loss of substance due to trauma or oncological excision may have relevant functional and aesthetic implications. We report our experience in twenty-one cases of propeller flaps for the treatment of loss of substance of the upper and lower limbs. The etiology of defect was tumor excision in nine cases, trauma in seven cases, surgical wound complications in four cases, and chronic osteomyelitis in one case. Clinical results were favorable in most cases and eighteen flaps survived. We observed an overall complication rate of 33% with four cases of superficial epidermolysis that spontaneously healed and three cases of partial flap loss ranging from 10 to 50% that required surgical revision by means of skin graft (two cases) or ALT free flap (one case). Propeller flap harvesting requires great care and experience, and potential complications may occur even in expert hands. When indicated by the characteristic of the defect, these flaps can be a useful surgical option for the treatment of loss of substance of upper and lower limbs.