In September 2008, Covidien Energy-based Devices, a market leader in advanced energy-based surgical systems, announced the launch of the Evident MW Ablation System, providing physicians with a powerful new technology to ablate soft tissue.


Device Capabilities

The Evident system (the first microwave ablation system available globally) uses microwave energy at 915 MHz to coagulate soft tissue during percutaneous, laparoscopic, and open surgical procedures. Microwave energy emanates from the feed point of the radiating section of the antenna, causing water molecules to spin. This creates heat by generating friction, which coagulates the tissue. With microwave ablation, there is no current flow through the patient, eliminating the need for grounding pads.


This major technological advance allows surgical oncologists, interventional radiologists, hepatobiliary surgeons and other medical specialists to perform soft tissue ablation during percutaneous, laparoscopic or open procedures, and in less time than other forms of ablation; with the Evident MW Ablation System, ablation can take 10 minutes or less. The speed and efficiency of the system may mean less time in the operating room or radiology suite, and less time that patients need to spend under anesthesia.


Developing the Design

In the past, alternate energy modalities such as radiofrequency and cryotherapy have been used in operating rooms and radiology suites. But microwave energy, when applied in tissue, behaves differently than these other modalities, allowing for faster ablations. 


When developing the Evident MW Ablation System and instruments, researchers at Energy-based Devices focused on creating a product that offered ease of use. The system includes a microwave generator and two types of disposable instruments, or microwave antennas, which are inserted into the tissue under image guidance prior to applying energy. The percutaneous antenna has a saline-cooled shaft for maintaining low shaft temperatures at the skin site. The non-cooled surgical antenna is a single-connection instrument, which simplifies user setup.


Market Response

As a result of its ease of use and faster heating, the Evident MW Ablation System has been well-received in the medical device marketplace since its launch in September.


“Compared to other ablative systems, this microwave system has a more efficient heating mechanism,” said Robert Martin, M.D., Associate Professor of Surgery, Division of Surgical Oncology at the University of Louisville James Graham Brown Cancer Center. “This leads to faster, more efficient ablations that can be performed simultaneously, and thus leads to less time under anesthesia for the patient.”


Kristin Johnson is the Director of Research and Development of the Division of Interventional Oncology at Covidien Energy-based Devices