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Objective: Defect coverage of the ulnar aspect of the hand, wrist and hypothenar with an abductor digiti minimi muscle flap and split skin graft., Indications: Soft tissue defects of the ulnar aspect of the hand, wrist and hypothenar. Osteomyelitis of the fifth metacarpal bone., Contraindications: Large defects > 3 × 5 cm, complex hand trauma, injuries of the ulnar artery or within the area of the pedicle., Surgical Technique: Marking of the flap's rotational radius, using the pisiform bone as the center point. Ulnar skin incision and exposure and detachment of the distal flap pole, which is located at the level of the metacarpophalangeal (MCP) joint. Dissection of the abductor digiti minimi muscle flap up to the vascular pedicle in the area of the pisiform bone. Transposition and fixation of the flap onto the defect after opening of the tourniquet. Coverage of the muscle flap with a split skin graft. Wound closure of the donor side., Postoperative Management: Palmar cast splinting in intrinsic-plus position for 10 days physiotherapy. Scar care and compression glove for 3 months., Results: In total, 9 patients showed good results with a reliable defect coverage due to a constant anatomy and easy preparation.

Objective: Immediate two-step coverage of dorsal finger and thumb-tip soft-tissue defects with a dorsal flag flap, which can bridge over two fingers if necessary., Indications: Soft-tissue defects on the dorsal aspect of fingers between the metacarpophalangeal and the distal interphalangeal joint as well as on the tip of the thumb., Contraindications: Large defects, complex hand trauma, need of a sensible thumb tip, infections, noncompliance., Surgical Technique: Marking of the flap at the middle phalanx and its flagpole pedicle, containing the dorsal digital artery. The breadth should reach to the middle of the finger and the proximal pole should not cross the middle of the proximal phalanx. With tourniquet dissection of the flap above the peritendineum with respect of the dorsal digital artery and subcutaneous veins in the pedicle. Opening of the tourniquet, in the case of flap perfusion transposition of the flap into the defect. Coverage of the donor site with skin graft., Postoperative Management: Palmar cast splinting in intrinsic-plus position for 1 week, followed by physiotherapy. Pedicle separation after 3 weeks. Continuation of physiotherapy and scar care., Results: In 2006, ten patients were operated on, three of them for reconstruction of the thumb tip. All patients showed a survival of the flap and a good wound healing without complications. One patient developed a flexion contracture at the donor finger due to noncompliance following immobilization. The functional and aesthetic results were satisfactory in all patients, the average DASH Score ("Disabilities of the Arm, Shoulder and Hand") was 16.4, mainly due to the residuals of the overall injury.

Aims: Demyelination plays a crucial role in neurodegenerative processes and traumatic disorders. One possibility to achieve remyelination and subsequent restoration of neuronal function is to provide an exogenous source of myelinating cells via transplantation. In this context, mesenchymal stem cells (MSCs) have attracted interest. They are multipotent stem cells that differentiate into cells of the mesodermal lineage like bone, cartilage, fat, and muscle. Although adult, their differentiation potential is remarkable, and they are able to transdifferentiate., Methods: We transformed cultivated rat MSCs into myelinating cells by using a cytokine cocktail. Transdifferentiated MSCs were characterized by an enhanced expression of LNGF-receptor, Krox20, and CD104, and a decreased expression of BMP receptor-1A as compared to untreated MSCs. The myelinating capacity was evaluated in vitro and in vivo. Therefore, PC12 cells, normally unmyelinated, were cocultivated with MSCs, transdifferentiated MSCs, and Schwann cells, or the respective cells were grafted into an autologous muscle conduit bridging a 2-cm gap in the rat sciatic nerve. Myelination of PC12 cells was demonstrated by electron microscopy. In vivo, after 3 and 6 weeks regeneration including myelination was monitored histologically and morphometrically. Autologous nerves and cell-free muscle grafts were used as control., Results: Schwann cells and transdifferentiated MSCs were able to myelinate PC12 cells after 14 days in vitro. In vivo, autologous nerve grafts demonstrated the best results in all regenerative parameters. An appropriate myelination was noted in the Schwann cell groups and, albeit with restrictions, in the transdifferentiated MSC groups, while regeneration in the MSC groups and in the cell-free groups was impaired., Conclusion: Our findings demonstrate that it may be possible to differentiate MSCs into therapeutically useful cells for clinical applications in myelin defects.