Monitoring of Tissue Transfer Flaps by Modulated Imaging (MI) Spectroscopy

Tissue transfer flaps are a method of moving tissue from a donor location to a recipient location. In the case of a free tissue transfer flaps, the blood vessels to the transferred tissues are detached and then re-attached to different arteries & veins at the recipient site. The process of reconstructive surgery using tissue transfer flaps allows for improved results in terms of functionality, aesthetic appearance, and psychological well-being in patients requiring reconstructive surgery after cancer resection or trauma. The process of reconstructive surgery using tissue transfer flaps is not without complications. These complications may include acute arterial or venous occlusion, as well as the development of late complications such as fat necrosis and flap atrophy.

The purpose of this pilot study is to determine if a novel, unique, portable, non-contact optical imaging device developed at the Beckman Laser Institute called Modulated Imaging (MI) can detect changes in a flap's optical properties, which can correlate with arterial or venous occlusion or with the development of fat necrosis or flap atrophy. The study would also evaluate if changes in the tissue transfer flap's optical properties, as detected by the device could be employed as a monitoring device in the post-operative period after reconstructive surgery. The MI device's detection of specific optical properties of a tissue flap could also potentially be used as a diagnostic tool to predict the likelihood of the development of fat necrosis or flap atrophy in a delayed fashion several months after reconstructive surgery.

Prior animal and clinical studies using similar devices have demonstrated that changes in the total hemoglobin concentration and percentage of oxygenated hemoglobin in the tissue transfer flap can be used to differentiate between arterial and venous occlusion. These other similar devices have been shown to be able to detect venous occlusion prior to clinical manifestations of venous occlusion using standard monitoring methods. This early detection of venous occlusion has important implications. It is well established that early detection and surgical re-exploration and correction of venous occlusion is associated with improved survival and salvage rates of tissue transfer flaps. It has been suggested in the reconstructive literature that the development of fat necrosis and flap atrophy are caused by a relative arterial or venous insufficiency, which could be detected using the MI device prior to the clinical manifestations of these complications.Patients undergoing reconstructive surgery at UCI Medical Center will be recruited for enrollment into the study. The study design requires following the patients and review their medical records in order to determine the clinical outcomes of their reconstructive surgery. The process of review of the medical record will require the review of both the in-patient medical record during the hospitalization in which the reconstructive surgery takes place and the outpatient medical record after surgery in order to observe for the possible development of the acute and delayed complications of reconstructive surgery.