ViewpointA Quick Evaluation of TRAM Flap Viability using Fingerstall-Type Tissue
Oximetry
Itaru Tsuge, MD; Tatsuki Enoshiri, MD; Susumu Saito, MD, PhD; Shigehiko Suzuki, MD, PhD

Z

one IV, the most distal region of the transverse rectus abdominis musculocutaneous (TRAM) flap, is wellknown as a region of poor circulation.1 We routinely use
the indocyanine green (ICG) test, which has been widelyused for decision-making regarding skin perfusion territory; however, the disadvantages of the test include the riskof an allergic reaction to ICG2 and the need for an expensive imaging system. Tissue oximetry, a system measuring
the tissue oxygen saturation (StO2), has shown promise inpostoperative flap monitoring.3 Recently, Kanayama andNiwayama4 developed a novel tissue oximetry technology,
which allows the circulatory condition of the skin to beevaluated using a fingerstall-type StO2 sensor. Then, theToccare device (Astem, Japan) was released in 20155. The
advantages of this technology include the light weight ofthe module (0.1 kg), mobility (it works with batteries), andthe short sampling time (0.5 s). We investigated the diagnostic potential of the Toccare device on the circulatory
condition of TRAM flaps according to the distribution ofStO2 values and the results of ICG tests. The medical ethics committee of our institution approved this study. The
investigation covered 2 reconstructive surgeries following
breast cancer removal (Fig. 1).

Fig.1. A Toccare device showing the StO2 value on its display. The
module is light (0.1 kg) and runs on batteries. The sampling time isvery short (0.5 s).
From the Department of Plastic and Reconstructive Surgery, Graduate
School of Medicine, Kyoto University, Kyoto, Japan.

Copyright © 2017 The Authors. Published by Wolters Kluwer
Health, Inc. on behalf of The American Society of Plastic Surgeons.
This is an open-access article distributed under the terms of the Creative
Commons Attribution-Non Commercial-No Derivatives License 4.0(CCBY-NC-ND), where it is permissible to download and share thework provided it is properly cited. The work cannot be changed in any
way or used commercially without permission from the journal.
Plast Reconstr Surg Glob Open 2017;5:e1494; doi:10.1097/GOX.0000000000001494; Published online 19 September 2017.

CASE 1

ICG test was performed and the outline of the fluorescence-negative region was marked (see figure, Supplemental Digital Content 1, which displays a right TRAM
flap for breast reconstruction, http://links.lww.com/PRSGO/A534). Then, StO2 values were measured at multiple
sites on the skin surface of the flap, which were regularly
placed at 2-cm intervals. During the measurement, a blue
sheet was positioned under the flap so as not to catch any
signals from the tissues beneath the flap. We also measured the StO2 values of the upper abdominal region andexcised skin as positive and negative controls, respectively.
For each of the 3 longitudinal sites, the StO2 values wereaveraged and recorded with a letter and a numeral, according to the side of the body and the distance from theICG border (e.g., “L3” indicates the site located 3 cm fromthe border on the left). Sites of decreased StO2 values located at R1-L1, which corresponded to the location of theoutline of the ICG-negative region. Accordingly, the partlateral to the site was excised. The surgery resulted in noflap failure.

CASE 2The tests were performed in the reverse order(Fig. 2). The boundaries with StO2 values of 45% and50% were determined first, and then the ICG test wasperformed. This determination took less than 5 minutes.
The fluorescence-negative region corresponded to theregion lateral to the 45% border. The estimated mean
StO2 value on the boundary between the ICG-positive
and negative regions was 41.3%. We excised the skin at
the ICG boundary; however, blood congestion was found.
We therefore further excised the skin to the 45% region.
Consequently, we confirmed the absence of blood congestion and flap failure.
Although the methods by which oximetry systems areused require further investigation, we are of the opinion
that the Toccare device has the potential to be an alternative to the ICG test.
Itaru Tsuge, MD
Department of Plastic and Reconstructive Surgery
Graduate School of Medicine
Kyoto University
54 Shogoin kawahara-cho
Sakyou-ku
Kyoto 606–8507
JapanE-mail: itsuge@kuhp.kyoto-u.ac.jp

Supplemental digital content is available for this­article. Clickable URL citations appear in the text.

www.PRSGlobalOpen.com

Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.

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PRS Global Open • 2017

Fig.2. Case 2: A right TRAM flap for breast reconstruction. The boundaries of the ICG border, StO2 45%
and 50% are marked on the flap. The StO2 values significantly decreased from 2 cm on the right side (R2)of the ICG border (n = 3). **p < 0.01 on a t test.

DISCLOSUREThe authors have no financial interest to declare in relation tothe content of this article. The Article Processing Charge was paid
for by the authors.
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Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.