Forehead flap perfusion monitored by laser speckle contrast imaging: Importance of flap length and thickness

Forehead flaps are commonly used in oculoplastic surgery to cover defects after tumor excision. Blood perfusion is vital for flap survival. The aim of this study was to monitor the perfusion in forehead flaps and investigate the impact of flap length and thickness. Nineteen forehead flaps in patients undergoing direct brow lift were studied. Perfusion was monitored using laser speckle contrast imaging, immediately after raising flaps consisting of epidermis, dermis, and subcutaneous tissue, and after removing the subcutaneous tissue resulting in a thin flap. Perfusion decreased gradually along the length, the mean value being 44% at 5 mm and 26% at 15 mm from the base, in thick flaps. Perfusion was significantly lower in thin flaps, being 13% when measured 15 mm from the flap base (p < 0.0024). Perfusion was better preserved in thick than in thin flaps. Very low perfusion was observed 16.7 mm (16.0–17.3 mm) from the base in thick flaps, and from 10.2 mm (9.8–10.6 mm) from the base in thin flaps (p < 0.0001). Flap thickness is important in maintaining adequate blood perfusion and thus increasing the probability of flap survival. This may be particularly important in long flaps and in patients with impaired microcirculation.