How to Map All Your Flap Perforators in 2 Minutes

Abstract

INTRODUCTION: Imaging modalities are changing clinical practice in plastic surgery and becoming more compact, more affordable, and easier to use. Over the last two decades, 3D imaging, ICG angiography, and virtual surgical planning have become commonplace for operative decision-making. Recently, mobile thermal imaging has demonstrated accuracy and consistency in determining perforator locations and visualizing the functional angiosomes.1 A study by Khouri et al in 1992 showed that the sensitivity of surface-temperature recording is 98%, and its predictive value is 75%.2 We sought to investigate whether recovery-enhanced mobile thermal imaging can be used to rapidly and reliably design perforator flaps. METHODS: Thermal imaging was compared with Doppler perforator mapping in five volunteers. Volunteers underwent traditional flap markings on one thigh and mobile thermal imaging (FLIR One Pro, FLIR Systems, Inc., Willsonville, Oreg.) on their contralateral thigh. In the traditional group, a line was drawn from the ASIS to the superolateral border of the patella with a 3-cm-radius circle at the midpoint, followed by perforator identification with a Doppler.3 On the contralateral thigh, ice cooling was performed for 10 seconds followed by inspection with the thermal camera. Time to identify at least three perforators, determination of perforator dominance, and perforator concordance were recorded. Additionally, in two consecutive patients undergoing anterolateral thigh flap reconstruction, flap design was examined based on traditional markings versus thermal imaging. RESULTS: Perforator identification was more rapid (136 seconds versus 232 seconds) and more likely to demonstrate perforator dominance (five versus one) using thermal imaging compared with traditional markings (P < 0.05). In both patients undergoing ALT flap reconstruction, three perforators were located with traditional and thermal imaging markings. In patient one, the middle perforator demonstrated dominance and true anastomoses to the surrounding perforators. In patient two, the transverse branch perforator demonstrated maximal intensity and poor connections to the distal perforators. After this, proximal perforator was divided and the thermal imaging worsened, resulting in resection of the proximal flap and change in flap design. Perforator location matched computed tomography angiographic findings in both patients. No postoperative flap compromise was encountered. CONCLUSIONS: Thermal imaging with ice cooling appears highly effective at rapid perforator and angiosome identification-based flap design. Recovery-enhanced thermography by ice cooling allows for dynamic visualization of angiosome perfusion area. Given improvement in technology and decreasing costs, mobile thermal imaging may become a reliable tool in flap design and flap monitoring. REFERENCES: 1. Pereira N, Valenzuela D, Mangelsdorff G, et al. Detection of perforators for free flap planning using smartphone thermal imaging. Plast Reconstr Surg. 2018;141(3):787–792. 2. Khouri RK, Shaw WW. Monitoring of free flaps with surface-temperature recordings: is it reliable? Plast Reconstr Surg. 1992;89(3):495–499; discussion 500–502. 3. Saint-Cyr M, Oni G, Lee M, et al. Simple approach to harvest of the anterolateral thigh flap. Plast Reconstr Surg. 2012;129(1):207–211.