Since introduction of using expanded skin made by subcutaneous implantation and gradual mechanical inflation of rubber balloon by Neuman in 1957, this method has been widely used and popularized in reconstructive plastic surgery.
The method has merits of technical simplicity, aesthetically more satisfactory outcome and less morbidity of donor site. In spite of the merits this method has been used with great fear of flap necrosis, as blood supply of the expanded skin may be interrupted by the surgical procedures and trauma of the mechanical expansion with a subsequent decrease in cutaneous blood supply. Therefore, this study was aimed to investigate the flap viability and the histological changes of expanded skin in 35 rabbits.
The animals were divided into experimental (n=28) and control groups (n=7).
Expansions of skin were made on the lateral thoracic wall of rabbits by insertion of 100ml, rectangular tissue expanders beneath the panniculus carnosus.
The experimental group was divided into 4,6,8 and 10wk. subgroups by expansion
perod, and had 7 rabbits for each. The rubber balloon was inflated to their maximum capacity by injecting 50ml, 25ml, 16.5ml and 12.5ml of saline solution at weekly over a period of 3,5,7 and 9wks respectively with each group. Each expander was removed 1 wk. after its last inflation. After removal of the expander, a flap(1.5x9 cm) was raised from the expanded skin and sutured to its bed. Also, a piece of specimen was taken from the expand-skin, and stained with hematoxylin-eosin for histologic observation. The rates of survival area were calculated on 7 days after the flap elevation. In the control group, skin flaps were raised in 7 rabbits in same size and in same location as
in experimental group, and survival rates and histological observation were investigated on the 7th postoperative day.
The results were as follows;
1. In the control group, the mean survival rate was 57.8 ± 9.5%, however, the
experimental groups showed the mean survival rates of 70.2 ± 9.1% (P<0.05), 71.5 ± 9.1% (P<0.01), 71.3 ± 7.4% (P<0.01), and 77.3 ± 7.9% (P<0.01)in 4,6,8 and 10wk. subgroup respectively (TableⅠ).
2. There was no relation between mean survival rates and the expansion period(TableⅠ).
3. The histological observations showed slight increases of dilated capillaries in dermis and prominent increase of dilated capillaries in the layer between the panniculus carnosus and the capsule formed around the expander (Fig. 3∼10).
|