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

## TL;DR

This paper reviews the use of implantable Dopplers to monitor buried free flaps in surgery, comparing two devices and their effectiveness based on literature and the authors' experience.

## Contribution

The paper provides a comparative analysis of two implantable Dopplers for buried flap monitoring, based on both literature and the authors' clinical practice.

## Key findings

- Cook Swartz is preferred for head and neck flaps due to fewer false positives.
- Synovis Flow Coupler is favored for DIEP flaps based on clinical practice.
- Literature confirms the effectiveness of implantable Dopplers over clinical evaluation for buried flaps.

## Abstract

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

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.

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.

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.