Immunohistochemistry of fibronectin and actin in ungrafted wounds and wounds covered with full- and split-thickness skin grafts

Skin grafting with the modified Meek technique in the standing horse using full thickness skin: Evaluation of acceptance, wound contraction and wound closure in chronic wounds

BACKGROUND

The modified Meek technique is not commonly used in equine wound management, despite the consistent reliable and superior results compared with other grafting techniques. Major drawbacks are the need for specialised, expensive equipment and general anaesthesia.

OBJECTIVES

To describe adjustments of the modified Meek technique enabling use in the standing horse without the need for the full equipment. This implied the use of full-thickness skin grafts manually harvested from the pectoral area and manually cut into micrografts. Graft acceptance; healing progress; and final functional and cosmetic result were outcome parameters.

STUDY DESIGN

Descriptive case series.

METHODS

Eight horses with traumatic wounds at the dorsal side of the carpus or tarsus, healing by second intention, were treated. Original wound areas and areas of graft acceptance and rejection were determined from post-processing of digital photographs and percentage acceptance, wound contraction and epithelialisation were calculated.

RESULTS

The initial mean wound area was 55.4 cm2 . Graft acceptance was 95.3 ± 2.5%. Wound closure was due to 46.0 ± 25.6% wound contraction and 54.0 ± 25.6% epithelialisation and resulted in 96.8 ± 1.9% reduction of the initial wound area 28.0 ± 8.5 days after grafting. The scar was flat, flexible and functional, usually with thin and regular hair growth. The adapted procedure was fast and efficient, with a learning curve for the increased manual work.

MAIN LIMITATIONS

Small study population.

CONCLUSIONS

This adapted modified Meek technique can successfully be performed in the standing horse and obviates the need for the full expensive equipment and general anaesthesia. The acceptance of the full-thickness grafts is excellent resulting in fast and satisfactory healing.

Enxertia de pele em oncologia cutânea

Em oncologia cutânea depara-se freqüentemente com situações em que a confecção de um enxerto é uma boa alternativa para o fechamento do defeito cirúrgico. Conhecer aspectos referentes à integração e contração dos enxertos é fundamental para que os cirurgiões dermatológicos procedam de maneira a não contrariar princípios básicos do transplante de pele. Os autores fazem uma revisão da classificação e fisiologia dos enxertos de pele, acrescendo considerações cirúrgicas determinantes para o sucesso do procedimento.

The modified Meek technique as a novel method for skin grafting in horses: evaluation of acceptance, wound contraction and closure in chronic wounds

REASONS FOR PERFORMING STUDY

The acceptance of skin grafts in horses is unpredictable and the final cosmetic result can be disappointing. Besides movement and infection, graft failure is often caused by chronic inflammation, inherently present during second intention healing of limb wounds in horses. In human burns affected by infection and inflammation, the acceptance of the island skin grafts of the modified Meek technique appeared to be better than meshed sheet skin grafts.

HYPOTHESIS

The percentage take of Meek micrografts is higher than of other techniques; and rates of both wound contraction and epithelialisation are increased.

METHODS

Large traumatic limb wounds of 13 horses healing by second intention were grafted using the modified Meek technique. Photographs of the wounds were taken at set intervals. Wound areas, and areas of acceptance and rejection were determined using a digital image post processor (Scion Image). The percentages of take, wound contraction and epithelialisation were calculated.

RESULTS

The initial mean wound area was 7500 mm2. Graft acceptance was mean +/- s.d. 93.7 +/- 5.9%. Wound closure was due to contraction (55.2 +/- 11.1%) and epithelialisation (44.8 +/- 11.1%) and resulted in a 96.7 +/- 3.6% reduction of the initial wound area 29.1 +/- 6 days after grafting. All wounds showed functional and cosmetic healing.

CONCLUSIONS

The method for skin grafting in horses achieved higher percentages of take than reported previously and consistent cosmetic and functional results. The grafts increased not only the rate of epithelialisation but also had a strong positive effect on wound contraction, resulting in rapid closure and smaller scars.

POTENTIAL RELEVANCE

The modified Meek technique proved to be a novel technique for skin grafting equine wounds in clinical practice, which can be performed easily. The molecular background of the increase of wound contraction by the grafts may provide a clue in the search for medicinal stimulation of wound contraction during second intention healing.

Effect of full-thickness skin graft initial dimension on secondary wound contraction: experimental study in rats

BACKGROUND

The size of a full-thickness skin graft (FTSG) is typically determined using a pattern of the defect usually obtained following excision of a skin lesion.

OBJECTIVE

The aim of this experimental study is to investigate the effects of various graft sizes on secondary wound contraction.

METHODS

Four 2.5 x 2.5 cm defects were created on the backs of 20 rats. Defect A was left to heal by secondary intention. The graft obtained from defect B (exact size graft) was sutured to its original bed. The wound of defect C (large graft) was patterned, and this was used to obtain a generous graft from the abdomen. A presized 1.5 x 1.5 graft obtained from defect D (small graft) was sutured to its original wound. Graft areas on days 0, 3, 7, 10, 14, 18, and 21 were calculated and converted into a percentage of the original wound size. Analysis of variance was used for statistical comparison. Open wounds reached a final wound size of 5% at day 21. Exact-size grafts showed the least secondary contraction rate (74.19 +/- 4.30 %) (p < .05).

CONCLUSION

A graft in the size of a planned excision preserves its original area better than grafts larger or smaller in size in the rodent model. The size of a FTSG is an important factor in preventing secondary wound contraction. However, it should be stressed that the results of this study cannot necessarily be extrapolated to real clinical scenarios without further detailed studies.

Fist position for skin grafting on the dorsal hand: II. Clinical use in deep burns and burn scar contractures

The fundamental problem in all types of hand burns is a loss of skin and subsequent deformities. The goal of skin grafting on the dorsal hand is to graft a sufficient amount of skin, as much as the original amount, and to restore normal hand function without secondary deformities. The safe, or Michigan, position commonly has been used for immobilizing the hand. However, this position is to protect hand function rather than to provide for adequate skin grafting. This institution has developed a new hand position (the fist position) for grafting the greatest amount of skin on the dorsal side of the hand. In the fist position, the hand is positioned flexing all joints of the wrist and the fingers and maximally stretching the dorsal surface of the hand before skin grafting. Ten hands with deep second- or third-degree burn (n = 6) and burn scar contracture (n = 4) of the dorsal hand in eight patients were treated with split-thickness skin grafting after immobilizing in the fist position. The burns and contractures involved nearly the total area of the dorsal hand. The hand was kept in the fist position for 7 to 9 days after skin grafting. Excellent functional and cosmetic results were observed in all cases during the follow-up period of 6 months to 2 years. Complications resulting from hand immobilization for a short period did not occur. The fist position may be a proper hand position for skin grafting to reconstruct the dorsal hand.

Fist position for skin grafting on the dorsal hand: I. Analysis of length of the dorsal hand surgery in hand positions

In skin grafting for reconstruction of burns and contracture deformities of the dorsal hand, the hand is kept in a proper position to provide the greatest amount of skin and to avoid the secondary functional deformity. The safe position has been commonly used for immobilizing the hand, but this is to protect the hand function rather than to provide maximal surface for skin grafting. Split-thickness skin graft contracts up to 30 to 50 percent of the original size owing to secondary contraction. If insufficient skin is grafted, contracture deformity of the dorsal hand may occur. To graft the greatest amount of skin on the dorsal hand, the hand should be kept preoperatively in a position flexing all joints of the wrist, metacarpophalangeal joints, and interphalangeal joints and maximally stretching the dorsal hand (a fist position). We studied the surface length of the dorsal hand between the wrist, the metacarpophalangeal joint, and the eponychium in the anatomic, safe, and fist positions of the right hand in 60 adults. Difference of total length between the anatomic and safe positions was not statistically significant (p > 0.05). The total length in a fist position was significantly increased in comparison with the other two positions (p < 0.05). In a fist position compared with the safe position, the increase in length of the dorsal surface of the proximal hand was 11 to 20 percent except in the thumb, and the increase in length of the dorsal surface of the finger was 12 to 17 percent. The increase in total length of a fist position was about 9 mm (7 to 8 percent) in the thumb and 20 to 32 mm (14 to 18 percent) in the index to little fingers. It suggests that the safe position fails to provide an increased dorsal hand surface area for skin grafting compared with the anatomic position. The greatest amount of skin can be grafted in a fist position. Hand immobilization in a fist position for 7 to 9 days after skin grafting has not resulted in irrevocable joint stiffness in our experience. If injury of the deep structures is not present, the hand should be immobilized in a fist position before skin grafting on the dorsal hand.