Objectives: Head and neck free flap success depends on the ability to accurately monitor the patency of the microvascular anastomoses. We investigated whether the implantable venous Doppler could accurately predict anastomotic patency.

Methods: We reviewed 133 consecutive microvascular free flap reconstructions in 128 patients after head and neck cancer resections between April 2000 and October 2005. There were 124 flaps monitored by an implantable Doppler probe placed around the venous anastomosis.

Results: The survival rate of flaps monitored by implantable Doppler was 98%. 13 flaps lost Doppler signals in the immediate post-operative period including one flap with clinical evidence of good perfusion. Twelve flaps explored emergently were found to have occlusion of the artery (2), vein (8), both vessels (1), and a hematoma (1). Eleven of the 12 flaps had flow restored (92% salvage). The sensitivity and specificity of a lost Doppler signal indicating an anastomotic occlusion was 100% and 99%, respectively. The positive predictive value of a lost Doppler signal indicating an anastomotic occlusion was 93%. The negative predictive value of a good Doppler signal indicating a patent anastomosis was 100%.

Conclusions: The implantable venous Doppler accurately predicts anastomotic patency after microvascular free flap for head and neck reconstruction.