[Latissimus dorsi transfer to restore thoracic malformation of Poland's syndrome].

OBJECTIVE: To study the methods and points for attention of latissimus dorsi muscle flap transplantation to correct the thoracic malformation of Poland's syndrome. METHODS: From 1995 to 2003, 10 patients were diagnosed of Poland's syndrome with absence of pectoris major muscle in all patients. The latissimus dorsi muscle flap was exposed and transferred through a vertical lateral thoracic cut and a short cut beneath the axillary fold. Reconstruction of the anterior axillary wall is one of the major goals to be achieved in this operation. RESULTS: All of the latissimus dorsi muscle flaps survived. Satisfactory outcomes were achieved after 1-2 years of follow-up. CONCLUSION: The latissimus dorsi muscle flap has a stable and reliable blood supply. It is an ideal muscle flap to restore the thoracic malformation of Poland's syndrome.

[The relationship between the changes in the blood flow of the exceedingly expanded skin and the viability of the flap].

OBJECTIVE: To investigate the relationship between the blood flow of the exceedingly expanded skin and the viability of the flap. METHODS: The piglets were set up as the animal model. They were divided into 7 groups according to different injection volume of the tissue expander, i. e. injection to 1/2 content, 3/4 content, full content, 50% over content, 100% over content, sham-operation control and normal control. At different stages of expansion, the blood flow and the amplitude of the expanded skin were examined by laser Doppler. The survival length of the expanded flap was measured. Furthermore, statistical analysis was performed. RESULTS: As the expansion volume increasing, the blood flow and the amplitude of the expanded skin increased, the survival length of the expanded flap increased also. In the meantime, the amplitude instability and vessel permeability increased. When the injection volume exceeded to 100%, the blood flow and the survival length of the expanded flap decreased. CONCLUSIONS: In soft tissue and skin expansion, increasing injection volume could increase the survival length of the expanded flap, while over-expansion to 100% content may cause blood flow disturbance.

[The correlation between the expansion volume and the contents of b-FGF and EGF in the expanded skin].

OBJECTIVE: To study the correlation between the expansion with different volume and the contents of the b-FGF and EGF in the expanded skin. METHODS: The piglets were used in the experiment,which were divided into 7 groups including the sham, the blank control,the experimental groups with inflation of 1/2 volume, 3/4 volume, full volume, 150% volume and 200% volume. When expansion was complete, b-FGF was measured using enzyme coagulate method. EGF was measured by radioimmunoassay. The data were analyzed statistically. RESULTS: The contents of b-FGF and EGF in the expanded skin was significantly higher than normal skin (P < 0.05). The difference in contents of b-FGF and EGF between the over-expanded skin and normal skin was more significant (P < 0.01). CONCLUSION: Expansion can lead to the increase of b-FGF and EGF contents in the expanded skin.The biological effects may be relative to epidermal hyperplasia and angiogenesis of the expanded skin.

Biomechanical properties of skin in vitro for different expansion methods.

OBJECTIVE: In plastic surgery, clinicians are interested in replacing conventional expansion by rapid expansion, because the expansion period could be shortened greatly. Also people are concerned that skin properties after rapid expansion might not approach those after conventional expansion. DESIGN: Biomechanical testing of skin for different expansion methods. BACKGROUND: It would be useful to know how much the mechanical properties of skin have been altered during rapid and conventional expansion and during different maintaining times. METHODS: Tensile strength, stress-strain relationship, stress relaxation, and creep were measured by a material testing machine. RESULT: The biomechanical properties of experimental specimens differ significantly from those of their controls immediately after expansion, however, the difference is reduced with time. With the same maintaining period, the biomechanical properties of rapidly expanded skin are similar to conventionally expanded skin. CONCLUSION: Rapid skin expansion did not demonstrate any deleterious effect when compared with the conventional expansion. Extension of the maintaining period can improve the biomechanical properties of expanded skin. Therefore, rapid expansion with an extended maintaining period is acceptable in clinical practice.

Biomechanical comparison between conventional and rapid expansion of skin.

This study was designed to investigate the effects of different surgical expansion regimens on the biomechanical features of expanded skin. Two hundred and forty millilitres expanders were implanted on the backs of six adult dogs. Six flaps were designed on the dorsum of each dog. After serial expansion, the expander was left beneath the skin for a certain period of time, which is called the maintaining period. Rapid expansion and conventional expansion with various maintaining periods were compared. The experimental result shows that the area gain of expanded skin surface had no significant difference between the rapid and conventional expansion. Both the tension in vivo and the instant stretch-back ratio increased during the expansion, but fell almost to control values after four weeks' maintaining period. Biomechanical properties in vitro, such as tensile strength, stress-strain, stress-relaxation, and creep were tested by INSTRON material testing machine. Results show that the biomechanical properties of expanded specimens differ significantly from those of their controls immediately after expansion. However, the difference reduces with prolongation of maintaining time. With the same maintaining period, the biomechanical properties of rapidly expanded skin are similar to conventionally expanded skin. We conclude that rapid skin expansion did not demonstrate any deleterious effect when compared with the conventional expansion. Extension of the maintaining period can improve the biomechanical properties of expanded skin and effectively reduce the stretch-back ratio. Therefore, rapid expansion with an extended maintaining period is acceptable in clinical practice.