Free flaps monitoring using implantable doppler: our experience and of the literature

Background: Buried free flaps monitoring cannot rely on clinical evaluation, which remains the gold standard in flaps with a skin paddle. A reliable way to monitor buried free flaps is through implantable dopplers, which provide a continuous and direct signal of anastomotic flow. Since the only way to ascertain a suspicion of vascular impairment in buried free flaps is through reoperative exploration, a high specificity is required together with a high sensitivity to avoid unnecessary theatre take-backs Methods: A systematic literature search was performed to screen three different databases (PubMed, Web of Sciences, and Embase) and using the following keywords: "Cook Swartz" AND "doppler" AND "flap" AND "monitoring" and "Synovis" AND "Flow Coupler" AND "flap" AND "monitoring". The indicators of efficacy and effectiveness of the two available implantable dopplers were analyzed and compared to our casistics. Results: The search using Cook Swartz thesaurus identified 116 articles while that of Synovis Flow Coupler 25 articles, of which only 26 and 6, respectively, fully satisfied our inclusion criteria. Conclusion: The literature search seems to confirm our current practice, with Cook Swartz (Cook Medical, Bloomington, IN) arterial placement preferred for head and neck buried free flaps and Synovis Flow Coupler (Synovis Life Technologies, Inc., St. Paul, MN) for buried DIEP flaps. This preferential placement reflects the higher rate of false positives when a vein is monitored in the head and neck, which is high mobile and prone to respiratory oscillations leading to probe dislocation or missing signal. (c) 2025 The Authors. Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)