Capillaroscopy for Monitoring Arterial Perfusion in Free Flap Surgery

Although various kinds of free flap monitoring techniques have been described, clinical flap assessment remains the most commonly used postoperative monitoring technique.[1] [2] In free flap surgery, venous thrombosis is more common than arterial thrombosis. However, arterial thrombosis is more difficult to detect than venous thrombosis using clinical flap assessment because arterial thrombosis results in a pale, ischemic flap which is not easy to identify compared to a dark, congestive flap due to venous thrombosis.[3] [4] Hence, the salvage rate is lower for arterial thrombosis than for venous thrombosis. One must, therefore, observe adequate surveillance for arterial thrombosis.

We suggest a novel method to monitor arterial blood supply using a capillaroscope (GOKO Bscan-Z; GOKO Imaging Devices Co., Ltd., Kanagawa, Japan). The capillaroscope is a microscope that aids the visualization of capillaries and their blood flow.[5] The magnification can vary between magnifications ×145 and ×590. The camera is a portable device; still and video images are projected to a monitor in real time. This test was approved by our Institutional Review Board and informed consent was obtained from the patients prior to the operation and flap monitoring.

A 45-year-old woman underwent autologous breast reconstruction using deep inferior epigastric perforator (DIEP) flap. Using the capillaroscope, the capillary perfusion of zone I of the skin paddle was examined before and after flap isolation and after flap revascularization. After DIEP flap elevation, the capillary perfusion of zone I was assessed, and abundant continuous capillary blood flow was confirmed ([Video 1]). On clamping the vascular pedicle, the capillary blood flow paused immediately. After flap isolation and microvascular anastomosis, the flap was revascularized; the capillary blood flow resumed shortly after the declamping of vascular pedicles. On postoperative day 1, the monitor skin paddle looked slightly pale, and arterial thrombosis was suspected. We first examined capillary perfusion of the monitor skin paddle with capillaroscopy; continuous capillary blood flow was observed ([Fig. 1]). Then, we performed pin prick test for confirmation and appropriate bleeding was observed. Thereafter, the postoperative course was uneventful and the flap survived.

Fig. 1 Photograph of postoperative flap monitoring using a capillaroscope. Continuous capillary blood flow was observed.

Video 1

The capillary blood flow was visualized using a capillaroscope.

Our findings indicate that, when abundant continuous capillary blood flow is observed under capillaroscopy, there would not be arterial pedicle trouble, and that, when the arterial blood supply is impaired, capillary blood flow pauses immediately.

The drawbacks of this monitoring method include the possibility of false-negative results of blood-flow monitoring. Suspended capillary perfusion may not necessarily indicate a compromise of the vascular pedicle, because capillary blood flow reflects peripheral blood perfusion which can be impaired temporarily or partially due to vascular spasm or other transient causes. Moreover, the device is not suitable for continuous blood flow monitoring; it can only be utilized intermittently.

Despite these limitations, capillaroscopy is a simple and effective method to monitor arterial perfusion in free flap surgery, with the ability to visualize blood circulation of the flap. Although further clinical cases are required to confirm its efficacy compared with other monitoring methods, capillaroscopy is a sensitive and noninvasive method to confirm arterial blood supply when arterial thrombosis is suspected.

Note

This report was published with the consent and permission of the patients involved.

• References

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• 2 Kohlert S, Quimby AE, Saman M, Ducic Y. Postoperative Free-Flap Monitoring Techniques. Semin Plast Surg 2019; 33 (01) 13-16
• 3 Bui DT, Cordeiro PG, Hu QY, Disa JJ, Pusic A, Mehrara BJ. Free flap reexploration: indications, treatment, and outcomes in 1193 free flaps. Plast Reconstr Surg 2007; 119 (07) 2092-2100
• 4 Nakatsuka T, Harii K, Asato H. , et al. Analytic review of 2372 free flap transfers for head and neck reconstruction following cancer resection. J Reconstr Microsurg 2003; 19 (06) 363-368 , discussion 369
• 5 Hern S, Mortimer PS. Visualization of dermal blood vessels--capillaroscopy. Clin Exp Dermatol 1999; 24 (06) 473-478