[Effect of vacuum drainage on the blood circulation of expanded flap in ear reconstruction]

To investigate the effect of vacuum drainage on blood circulation of expanded skin flap, so as to confirm suitable negative pressure for ear reconstruction.

21 patients (Auricular Reconstructive Center of Plastic Surgery Hospital, PUMC) were randomly divided into A, B, C 3 groups to receive vacuum drainage of: -20, -40 and -60 kPa, respectively. The length and width of reconstructed ears,which represented the swelling degree, were measured instantly and 5, 10 days postoperatively. The changes were calculated and reflected venous drainage of flaps. The temperature of proximal (concha) and distal (helix) part of the expanded flaps, which represented the arterial blood supply of flaps, was detected by infrared thermography after operation.

Five days after operation [(1.48 +/- 0.47) mm, (0.36 +/- 0.06) mm] and immediately [(1.67 +/- 0.69) mm, (0.40 +/- 0.16) mm)] , the changes of the length and width of reconstructed ear in group B was significantly low, while there was no statistically difference between group A and C (P > 0.05). The data between 10 days and 5 days after operation showed the same result. Along with the increase of the negative pressure, the swelling degree of reconstructed ears decreased firstly and then increased reversely ( P < 0.01 ). The flap temperature of reconstructed ears increased (P < 0.01), especially in proximal (concha) part (P < 0.01) , when the negative pressure increased (0 to -60 kPa).

Vacuum drainage has effect on both the venous drainage and blood supply. Negative pressure of -40 kPa can improve both the blood supply and venous drainage. It should be as reference for clinical application.