Applications of Smartphone thermal camera imaging system in monitoring of the deep inferior epigastric perforator flap for breast reconstruction

Abstract

The rise in Smartphone availability has brought about the development of multiple mobile applications and devices utilized in the clinical setting. Hardwicke et al. 1 have described the use of the FLIR ONE TM miniature thermal imaging camera (FLIR Systems, Wilsonville, Ore) in the evaluation of patients undergoing free tissue transfer. Thermal imaging captures the infrared radiation (IR) emitted from the skin surface and has been extensively used in plastic surgery as a means of determining burn depth, 2 detecting post-operative infection, 3 and postoperative free flap monitoring. 4 The smartphone-friendly product enables clinicians to utilize this technology at a fraction of the price of standard thermographic cameras. The device clips into the mobile phone charging port and requires the installation of the FLIR ONE mobile application to operate. It possesses both a thermal and digital camera that takes photographs simultaneously. The images are then merged by the software allowing for the addition of greater physical detail an otherwise raw thermal reading. Hardwicke et al. 1 argue that despite low image resolution and propensity for background thermal interference, it serves as an effective and inexpensive method of locating perforating vessels and evaluating overall tissue perfusion.We have used this in the peri-operative assessment of patients undergoing deep inferior epigastric perforator (DIEP) flap breast reconstructions. The device is portable and its software is similar to that of traditional Smartphone cameras which makes it easy to use and requires no additional training, however, factors such as vasoconstriction, warming blankets, or low ambient temperature significantly impact on accuracy. The heat signal identified by the camera strongly correlates with the position of the perforators as demonstrated by pre-operative radiological investigations and Doppler findings, even in the face of abundant overlying soft tissue (Fig. 1A). We propose that the perforators are best visualized following a 3-4 minute period of cooling of the skin as this will result in the faster warming of tissues immediately adjacent to the vessels allowing for more accurate localization ( Fig. 1B).We are currently investigating additional uses of this device including monitoring of digital replantation and pre-operative assessment of hand trauma patients. Our positive experience with the camera is in keeping with that described by Hardwicke et al. and there is currently a need for larger comparative studies in order to better evaluate the clinical applicability of the FLIR ONE TM thermal imaging system.

An Algorithm for Selecting Buoy Skin Paddle Design for Flap Monitoring in Total Autologous Breast Reconstruction After Nipple-Sparing Mastectomy

“…In NSM or revision surgery with an adequate soft tissue envelope, the entire native skin is preserved, and therefore, a skin paddle is most often not necessary, making the monitoring of the buried flap a more challenging process. Over the years, numerous techniques and devices have been developed for free flap monitoring, including tissue oximetry, laser Doppler flowmetry, thermal imaging, external temperature measurements, implantable Doppler devices, and microdialysis [15][16][17][18][19][20][21]. However, none of these methods have been proven to be superior in terms of early detection of anastomotic problems compared to traditional monitoring of an exposed skin paddle with clinical examination and handheld Doppler [18][19][20][21][22].…”

“…Over the years, numerous techniques and devices have been developed for free flap monitoring, including tissue oximetry, laser Doppler flowmetry, thermal imaging, external temperature measurements, implantable Doppler devices, and microdialysis [15][16][17][18][19][20][21]. However, none of these methods have been proven to be superior in terms of early detection of anastomotic problems compared to traditional monitoring of an exposed skin paddle with clinical examination and handheld Doppler [18][19][20][21][22]. Therefore, monitoring a flap with an exposed skin paddle remains the gold standard even after NSM autologous reconstruction.…”

Nipple‐sparing mastectomy with immediate breast reconstruction with a deep inferior epigastric perforator flap without skin paddle using delayed primary retention suture

“…Traditional flap monitoring using a handheld Doppler probe post‐free tissue transfer has been widely used with competitive accuracy without extra cost. Several newer technologies have become available to aid in this endeavor, including pulse oximetry, laser doppler, thermal imaging, color duplex, and smartphone photography 11–15 . These range from relatively simple ones to those that are highly sophisticated.…”

“…Several newer technologies have become available to aid in this endeavor, including pulse oximetry, laser doppler, thermal imaging, color duplex, and smartphone photography. [11][12][13][14][15] These range from relatively simple ones to those that are highly sophisticated. A major differentiating factor between them is the necessity for a skin paddle for monitoring.…”

Advances in flap monitoring and impact of enhanced recovery protocols

“…While high resolution thermal imaging cameras are typically rather expensive, the recently developed FLIR ONE (FLIR Systems, Inc., Wilsonville, OR) is a miniature thermal imaging camera which is lower resolution, smartphone‐compatible, and under $200. In two proof‐of‐concept studies, thermal imaging assessment of patients and healthy volunteers demonstrated that FLIR ONE could be useful in both preoperative free flap planning and intraoperative and postoperative monitoring, however larger comparative studies are needed …”