A new, custom-made device for flap protection in experimental rats

Mesenchymal Stem Cell Treatment Perspectives in Peripheral Nerve Regeneration: Systematic Review

Traumatic peripheral nerve lesions affect hundreds of thousands of patients every year; their consequences are life-altering and often devastating and cause alterations in movement and sensitivity. Spontaneous peripheral nerve recovery is often inadequate. In this context, nowadays, cell therapy represents one of the most innovative approaches in the field of nerve repair therapies. The purpose of this systematic review is to discuss the features of different types of mesenchymal stem cells (MSCs) relevant for peripheral nerve regeneration after nerve injury. The published literature was reviewed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A combination of the keywords “nerve regeneration”, “stem cells”, “peripheral nerve injury”, “rat”, and “human” were used. Additionally, a “MeSH” research was performed in PubMed using the terms “stem cells” and “nerve regeneration”. The characteristics of the most widely used MSCs, their paracrine potential, targeted stimulation, and differentiation potentials into Schwann-like and neuronal-like cells are described in this paper. Considering their ability to support and stimulate axonal growth, their remarkable paracrine activity, their presumed differentiation potential, their extremely low immunogenicity, and their high survival rate after transplantation, ADSCs appear to be the most suitable and promising MSCs for the recovery of peripheral nerve lesion. Clinical considerations are finally reported.

Comparison of contraction rates of epigastric and extended dorsal island skin flaps in rats

Flap surgery is a wide field in plastic and reconstructive surgery practice and experimental research is needed to improve surgical success. These research is often performed on rats. Rat is a loose-skinned animal and contraction of skin flaps on rats is an underestimated condition. Besides this variable contraction of survived and necrotic tissues may mislead calculations and results. In this study, contraction patterns of epigastric and dorsal island skin flaps were investigated to identify this phenomenon. Forty-two male Sprague-Dawley rats were divided into four groups. Eleven epigastric flaps with unilateral pedicles, 11 epigastric flaps with bilateral pedicles, 10 extended dorsal island skin flaps with unilateral pedicles, and 10 extended dorsal island skin flaps with bilateral pedicles were prepared. Total, necrotic and viable flap areas were calculated from standardized photographs which were taken daily. The animals were placed on marked papers and image processing software was used the calculate flap areas from the photographs. Respect to these daily flap areas, the contraction rates in epigastric flaps were highly significant. The area loss in necrotic tissues were faster than the viable areas. Compared to the epigastric flaps, the contraction was not significant in extended dorsal island skin flaps flap groups. In conclusion, the rat extended dorsal island skin flap is a more reliable model for experimental flap research, which is resistant to contraction, when compared to the epigastric skin flap model.

Saphenous artery-based flap models in rats: new flap designs for experimental studies

BACKGROUND

Experimental research using laboratory animals provides substantial data about reconstructive surgery. However, the literature does not include any experimental studies that have used flap models on the hind limbs of rats. To gain an understanding of the physiology of lower-extremity flaps and of flap failures, this study assessed the cutaneous perforators of the saphenous artery, and new flap models were designed for the hind limbs of rats.

MATERIALS AND METHODS

The experiment was designed to include three stages and used 35 rats. The first stage involved mapping the perforators of the saphenous artery. In the second stage, the contents and structures of McFarlane, epigastric, and anterior hind limb flap tissues were compared histologically. The third stage of the study involved designing and comparing different flaps for the hind limbs of the rats and included random flaps, perforator-based peninsular flaps, perforator-based island flaps, and perforator-based flaps with rotated pedicles. Postoperative necrosis ratios were evaluated using computer-based software.

RESULTS

Mapping of the saphenous artery perforators revealed an average of 2.2 septocutaneous arteries in each hind limb. Histologic studies showed thick dermis and panniculus carnosus in the McFarlane flaps, thick dermis, and thin panniculus carnosus layers in the epigastric flaps, and thin subcutaneous tissue with no panniculus carnosus tissue in the skin of the hind limbs. The results of the flap studies that used random flaps showed a 52.4% necrosis, while there was no necrosis when perforator-based peninsular flaps, island flaps, and flaps with rotated pedicles were used.

CONCLUSIONS

New flap models used on the saphenous artery perforators of the hind limbs of rats can provide valuable information about the physiology of lower-extremity flaps. New studies can also be designed based on these flap models to acquire more knowledge about pathologic conditions such as ischemia and venous insufficiency.

Intra and postoperative evaluations of microcirculation and micro-rheological parameters in a rat model of musculocutaneous flap ischemia-reperfusion

PURPOSE

To examine how the ischemia-reperfusion injury of latissimus dorsi-cutaneous maximus (LDCM) musculocutaneous flap affects the microcirculatory (flap's skin surface) and hemorheological parameters, and whether an intraoperative deterioration would predictively suggest flap failure in the postoperative period.

METHODS

Ten healthy male rats were subjected to the study. In Group I the left flap was sutured back after 2-hour, while the contralateral side was right after its elevation. In Group II the same technique was applied, but the pedicle of the left flap was atraumatically clamped for 2-hour. The contralateral side was left intact. On the flap skin surface laser Doppler tissue flowmetry measurements were done before and after and during the protocols applied in the groups. Microcirculatory and hemorheological examinations were done postoperatively.

RESULTS

The microcirculatory parameters significantly decreased during immobilization and ischemia. Afterwards, all the regions showed normalization. In the retrospective analysis there was a prominent difference between the microcirculatory parameters of necrotic and survived flap during the early postoperative days (1-3) in Group II. Erythrocyte aggregation and deformability showed only slight differences.

CONCLUSIONS

Two-hour ischemia and reperfusion caused deterioration in latissimus dorsi-cutaneous maximus flap microcirculation. Predicting the possible postoperative complication, the intraoperative laser Doppler measurement can be informative.