The project aims to develop photoacoustic (PA) imaging to measure perfusion in a more precise manner and with less artifacts than existing laser-based techniques.
Many of today's reconstructive surgical techniques in the eye area involve extensive surgery and often multiple procedures to ensure perfusion. In some cases, the patient’s eyelids are sutured together for three weeks or more and the blood supplying surgical flap is not cut until one assumes that blood circulation is secure. Interestingly, perfusion has never been measured in these surgical flaps and transplants. The reason for this is that the surgery techniques were established many decades ago, long before modern blood perfusion monitoring techniques were invented. Photoacoustic (PA) imaging have proven promising for measuring perfusion, oxygen retention and tissue viability, but have never been tried before for reconstructive surgery. To evaluate photoacoustic imaging for perfusion monitoring, a safe model with low variability and high reproducibility is first needed. Therefore, local anesthesia containing adrenaline is initially used as a method of inducing perfusion changes in the tissue. The local anesthetic is injected subcutaneously into the forearm to induce a measurable hypoperfusion and which can be measured by photoacoustic imaging. Once the techniques have been evaluated, further studies are planned for reconstructive surgery in the eye area of patients.
Animal studies with PA imaging show high resolution images in which one can measure the tissue oxygen saturation. No study has yet been done to study oxygenation in human reconstructive surgery. The work is done in collaboration with Associate Professor Magnus Cithio's research group at Biomedical Engineering, Lund University Faculty of Engineering.
Tenland K, Berggren JV, Dybelius Ansson C, Hult J, Dahlstrand U, Lindstedt S, Sheikh R, Malmsjo M: Blood Perfusion in Rotational Full-Thickness Lower Eyelid Flaps Measured by Laser Speckle Contrast Imaging. Ophthalmic Plast Reconstr Surg 2020, 36(2):148-151.
Berggren J, Castelo N, Tenland K, Dahlstrand U, Engelsberg K, Lindstedt S, Sheikh R, Malmsjo M: Revascularization of free full-thickness skin grafts in periorbital reconstructive surgery monitored using laser speckle contrast imaging. Ophthalmic Plast Reconstr Surg 2020.
Ansson CD, Berggren JV, Tenland K, Sheikh R, Hult J, Dahlstrand U, Lindstedt S, Malmsjo M: Perfusion in Upper Eyelid Flaps: Effects of Rotation and Stretching Measured With Laser Speckle Contrast Imaging in Patients. Ophthalmic Plast Reconstr Surg 2020, 10.1097/IOP.0000000000001614.
Tenland K, Berggren JV, Dybelius Ansson C, Hult J, Dahlstrand U, Lindstedt S, Sheikh R, Malmsjö M. Blood Perfusion in Rotational Full-Thickness Lower Eyelid Flaps Measured by Laser Speckle Contrast Imaging. Ophthalmic Plast Reconstr Surg. 2019 Nov 22.
Berggren J, Tenland K, Ansson CD, Dahlstrand U, Sheikh R, Hult J, Engelsberg K, Lindstedt S, Malmsjö M. Revascularization of Free Skin Grafts Overlying Modified Hughes Tarsoconjunctival Flaps Monitored Using Laser-Based Techniques. Ophthalmic Plast Reconstr Surg. 2019 Jul/Aug;35(4):378-382.
Tenland K, Memarzadeh K, Berggren J, Nguyen CD, Dahlstrand U, Hult J, Engelsberg K, Lindstedt S, Sheikh R, Malmsjö M. Perfusion Monitoring Shows Minimal Blood Flow From the Flap Pedicle to the Tarsoconjunctival Flap. Ophthalmic Plast Reconstr Surg. 2019 Jul/Aug;35(4):346-349.