METABOLISM IN MYOCUTANEOUS FLAPS STUDIED BY IN-SITU MICRODIALYSIS

The aim of this investigation was to follow the metabolism of myocutan eous flaps using microdialysis. After subcutaneous implantation of a m icrodialysis catheter into the flap tissue, serial samples were collec ted and changes in composition of the extracellular fluid assessed. Te n women underwent reconstructions with transverse rectus abdominis myo cutaneous (TRAM) or latissimus dorsi flaps. Glucose, glycerol, and lac tate concentrations were measured in the flaps and compared with those in adipose control tissue located over the hip. A transient rise in g lucose was observed initially in the flaps. The glycerol concentration also increased significantly: and remained increased for approximatel y 12 hours after the operation. The lactate concentration changed in t he same direction, but stayed elevated in the flap tissue during the e ntire investigation (24 hours). Neither of these parameters changed to the same extent in the control tissue. In one of the patients a haema toma developed postoperatively in the flap. This incident was accompan ied by a sharp decline in glucose, and marked additional increases in glycerol and lactate concentrations. It may well be that this ''metabo lic pattern'' in flap tissue signals threatening flap ischaemia. If so , this new microdialysis technique may be useful as a postoperative su rveillance tool in myocutaneous flap surgery.