Abstract: A Critical Evaluation of Human Perception in Conventional Flap Monitoring Versus Spacial Frequency Domain Imaging (Plastic Surgery 2014)

Saturday, October 11, 2014: 2:40 PM

Jonathan C Rimler, MD , Aesthetic and Plastic Surgery Institute, University of California Irvine, Orange, CA

Adrien Ponticorvo, PhD , Beckman Laser Institute and Medical Clinic, Univeristy of California at Irvine, Irvine, CA

Eren Taydas, MD , Beckman Laser Institute and Medical Clinic, University of California at Irvine, Irvine, CA

Amaan Mazhar, PhD , Modulated Imaging Inc, Irvine, CA

Thomas Scholz, MD , Aesthetic and Plastic Surgery Institute, University of California at Irvine, Orange, CA

Christopher L Ellstrom, MD , Aesthetic and Plastic Surgery Institute, University of California Irvine, Orange, CA

June Tong, BS , Beckman Laser Institute and Medical Clinic, University of California at Irvinve, Irvine, CA

Gregory R. D. Evans, MD , Aesthetic and Plastic Surgery Institute, University of California Irvine, Orange, CA

David J Cuccia, PhD , Modulated Imaging Inc., Irvine, CA

Anthony J Durkin, PhD , Beckman Laser Institute and Medical Clinic, University of California at Irvine, Irvine, CA

Presentation PDF file

Introduction

Detection of failing tissue flaps before clinically apparent changes are noticeable has the potential to improve post-operative flap management and salvage. This study demonstrates a model to quantitatively compare clinical appearance, as recorded via digital camera, with spatial frequency domain imaging (SFDI), a non-invasive imaging technique utilizing wide field patterned illumination to generate images of tissue oxygen saturation.

Methods

Utilizing a swine pedicle model, 8 pigs had bilateral fasciocutaneous pedicle flaps raised in the abdominal area. The flaps were skeletonized on the deep inferior epigastric vasculature. With each pig acting as it own control, blood flow in either the artery (4 pigs) or the vein (4 pigs) was carefully regulated with occlusion cuffs and monitored with ultrasound probes. Throughput was sequentially reduced by 25%, 50%, 75%, and 100% of baseline values for 30 minutes at a time and restored to normal flow for 30 minutes between each occlusion. The flap color changes recorded by a digital camera were quantified in order to predict which occlusion levels were visible to the human eye. SFDI was simultaneously used to measure the changes in physiological parameters including total hemoglobin and oxygen saturation associated with each occlusion and then contrasted with the visual data.

Results

There were no statistically significant changes in color above the noticeable perception levels associated with human vision during any of the partial occlusion levels or the 100% level. Utilizing SFDI there were statistically significant changes in oxygen saturation detected at the 75% and 100% levels after 30 minutes of arterial or venous occlusion. There was significant variability between different animals with some showing identifiable oxygenation changes at lower levels of occlusion.

Conclusions

As demonstrated by the color imaging data, visual flap changes are difficult to detect even when significant occlusion has occurred. SFDI is capable of detecting changes in tissue oxygen saturation as a result of partial blood flow occlusions to pedicle flaps before they are visible to the human eye. Utilization of SFDI may allow for improved response times and salvage of compromised flaps in comparison to conventional monitoring techniques.

25124 A Critical Evaluation of Human Perception in Conventional Flap Monitoring Versus Spacial Frequency Domain Imaging