Innovation in Free Flap Monitoring: Intra-Flap Vascular Catheterization (IFVC) Technique

Background:

Thrombosis at the anastomotic site is a major problem in free tissue transfer. In order to detect thrombosis, various methods have been described, including clinical monitoring, implantable Doppler probe, oximetry, visible light spectroscopy, multispectral imaging, CO₂monitoring, laser Doppler flowmetry, glucose and lactate measurements and ultrasound. Although there is evidence of improvement of flap salvage rates with several methods, these methods are limited to monitoring. If we can monitor, prevent, and treat the thrombosis simultaneously, this would be innovative. We developed a new method for free flap monitoring called the intra-flap vascular catheterization technique (IFVC), which enables us to prevent thrombosis, monitor the flap in a highly sensitive manner, and, at the same time, treat small thromboses simply by injecting drugs from the catheter. This is the first report to show that monitoring, prevention, and treatment of thrombosis are possible by a single method.

Patients and Methods:

Between 2015 and 2017, a total of 15 patients underwent free tissue transfer by a single surgeon in St. Mary’s Hospital by using this technique. After the anastomosis, catheters were inserted to the side branch of the flap pedicle in both the artery and vein. The catheters were connected to the pressure monitor and infused either urokinase or saline to prevent thrombosis. Then, 360 U of urokinase were injected into the artery if an arterial pressure decrease was detected, and 5 ml of saline were injected into the vein if a venous pressure increase was detected. Fifteen consecutive patients were operated with this technique.

Results:

All flaps survived, no major re-operation was required, and re-anastomosis during the initial operation was not needed in any cases.

Conclusion:

IFVC may become a powerful tool for surgeons to avoid re-operation in free tissue transfer, even though it adds an hour of operation time. This may be called an innovation in monitoring, because IFVC enables monitoring, prevention, and treatment of thrombus by a single method.