Blood Perfusion in Human Eyelid Skin Flaps Examined by Laser Speckle Contrast Imaging-Importance of Flap Length and the Use of Diathermy

Purpose: It is well known that blood perfusion is important for the survival of skin flaps. As no study has been conducted to investigate how the blood perfusion in human eyelid skin flaps is affected by the flap length and diathermy, the present study was carried out to investigate these in patients. Methods: Fifteen upper eyelids were dissected as part of a blepharoplastic procedure, releasing a 30-mm long piece of skin, while allowing the 5mm wide distal part of the skin to remain attached, to mimic a skin flap (hereafter called a skin flap). Blood perfusion was measured before and after repeated diathermy, using laser speckle contrast imaging. Results: Blood perfusion decreased from the base to the tip of the flap: 5mm from the base, the perfusion was 69%, at 10mm it was 40%, at 15mm it was 20%, and at 20mm it was only 13% of baseline values. Diathermy further decreased blood perfusion (measured 15mm from the base) to 13% after applying diathermy for the first time, to 6% after the second and to 4% after the third applications of diathermy. Conclusions: Blood perfusion falls rapidly with distance from the base of skin flaps on the human eyelid, and diathermy reduces blood perfusion even further. Clinically, it may be advised that flaps with a width of 5mm be no longer than 15mm (i.e., a width:length ratio of 1:3), and that the use of diathermy should be carefully considered.