Real-Time Assessment of Free Flap Capillary Circulation Using Videocapillaroscopy.

BACKGROUND: Free tissue transfer is a common method of reconstruction for various surgical defects. Many clinical assessment methods, including flap color monitoring and capillary refill time measurements, are commonly used to assess the microcirculation of the flap, yet there is no objective tool available that can clear real-time visualization of the flap microcirculation. The purpose of this study was to use a novel videocapillaroscope to evaluate the circulation changes on free flap skin surfaces while purposely clamping pedicle vessels. METHODS: Ten patients who underwent free flap transfer for head and neck cancer from November of 2019 to June of 2020 were included in the study. Videocapillaroscopic observation was performed after flap elevation, and changes in the flap skin capillary circulation with artery-controlled and vein-controlled clamping were recorded. RESULTS: Average total surgery time was 517.91 minutes (SD, 73.3 minutes), average flap elevation time was 102.9 minutes (SD, 18.3 minutes). When the pedicle artery or vein was purposely clamped, the movement of red blood cells in blood vessels stopped; when clamps were removed after 60 seconds, the restoration of red blood cell movements was rapidly observed. When the pedicle artery was clamped, the number of visualizable blood vessels decreased and flap color became relatively white. When the pedicle vein was clamped, the number of visualizable blood vessels increased, and flap color tone had a tendency toward red. CONCLUSION: Novel videocapillaroscopy can be utilized for objective real-time flap monitoring by directly visualizing flap skin capillary microcirculation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Dynamic Changes on Video-capillaroscopy and Potential Microsurgical Application: Temperature and Skin Surface Readings.

Video-capillaroscopy is being explored as a potential tool for microsurgical flap monitoring. A detailed examination of the effect of temperature on capillary changes using video-capillaroscopy is yet to be investigated. We analyzed the video-capillaroscopy findings on different skin areas often used for flap harvest at normal body temperatures and at lower temperatures. Skin capillaries at the lateral thigh, anterior forearm, mid-axillary line, abdomen, and fingertips were observed using video-capillaroscopy in 20 healthy Japanese individuals. Further, ImageJ software was used to measure the blood vessel area and blood flow velocity, and comparisons were drawn between normal body temperature and lower body temperature states. All measures of blood vessel area and average blood flow velocity for the different anatomical regions were significantly different before and after cooling (P < 0.001). The mean reduction rate of the vessel area was significantly different among anatomic regions (P < 0.001). Post-hoc analysis revealed a significant difference in the vessel area reduction rate between anatomic areas (P < 0.05); except when comparing the thigh versus finger, the forearm versus abdomen, and the mid-axillary line versus abdomen. The mean blood flow velocity was significantly different among anatomic regions (P < 0.001). Post-hoc analysis revealed a significant difference between the thigh and forearm (P = 0.009), the forearm and fingertip (P = 0.001), and the abdomen and fingertip (P = 0.004). Decreasing the skin temperature resulted in a significant vasoconstriction and reduction in capillary flow velocity. It is imperative to keep the monitored area warm during video-capillaroscopy assessment to avoid false diagnosis of vascular occlusion.