The MEA system is a software-controlled device designed to ablate the endometrial lining of the uterus using microwave energy at a fixed frequency of 9.2GHz. It consists of the MEA system console that houses a control module with an embedded computer and user touch screen with colour display, a microwave generator, and a power supply. The microwave generator employs a high stability source with a design life of 5 years or 5,000 duty cycles. Additional components consist of a reusable hand-held applicator, a pneumatic footswitch, coaxial and data cables, a printer (optional), a power cord, and a portable trolley. The MEA applicator serves as the interface between the Microwave module and the patient. It is a one-piece reusable instrument used to introduce microwaves at 9.2 GHz into the uterus via the cervix.

The shaft is graduated along its length in whole centimetre units. A solid black band extending 35 mm below the tip is used to indicate to the surgeon the tip position with respect to the endo-cervical canal. A solid yellow band extending 7 mm beyond the black band is used to call attention to the imminence of the black band during treatment.

The applicator is connected to the MEA system by two cables. The coaxial cable carries the microwave energy from the microwave module to the applicator. The data cable carries temperature data to and from the applicator, and allows continuous temperature monitoring of tissue in the treatment field.

The MEA applicator must be cleaned and sterilised prior to each use.

The control module contains the hardware and software components necessary to guide the user with system and treatment instructions for safe operation of the MEA system. Control of the embedded PC and MEA system is achieved via a resistive touch panel (touch screen) installed in the control module. Using the touch screen, the operator can functionally control all aspects of its operation.

The MEA treatment system has an integrated computer that allows information to be recorded onto a hard storage disk, such as patient number, endometrial thickness, uterine length as well as all of the operative microwave data (including total microwave power and which applicator is used). The information can also be printed for case note documentation once the treatment is complete. This data can also be copied to an external data storage facility via the floppy disk drive at the rear of the MEA system.

Principle of Operation

The coaxial cable carries the microwave energy from the microwave generator to the reusable applicator. During use, the applicator is inserted into the uterine cavity until the applicator tip reaches the fundus. Power to the applicator is controlled by a foot switch operated by the surgeon. The microwave energy is applied by depressing the footswitch connected to the control unit. Microwave energy emanates semi-radially from the applicator tip and is absorbed by the surrounding endometrial tissue. A data cable connected to the applicator transmits temperature measurements from the applicator tip and surrounding endometrial tissue to a colour display providing the surgeon with real-time visual feedback of the treatment temperature. Data such as the serial number of the applicator and its usage history is recorded. The microwave energy heats the endometrium, causing the temperature to rise. Likewise, when the applicator tip is moved to an untreated area, the temperature falls. The surgeon uses this graphical response to control the depth and coverage of heating during the MEA treatment. The applicator is moved slowly from side to side in the fundal area until the treatment temperature reaches the target temperature range (70 to 80 °C) displayed on the treatment screen. At this point, the endometrium in the fundal region is completely ablated (coagulated) and the treatment is continued with side-to-side movements while simultaneously withdrawing the applicator from the uterine cavity, carefully maintaining therapeutic temperature and watching the graduations on the applicator shaft until the end of the treatment band is visible. This treatment process will completely ablate the entire uterine cavity. The system achieves complete endometrial ablation by heating a 5-6 mm layer of intrauterine tissue to therapeutic temperature levels for the duration of the treatment, which averages 3 minutes for the normal size uterus (75-85 mm, respectively). When the applicator tip reaches the internal cervical os, the footswitch is released, which deactivates the microwave energy and the applicator is fully withdrawn.

Safety features include warnings and cut-out devices that are incorporated into the system. The applicator cannot be activated unless the tip is close to body temperature. In the unlikely event of an applicator malfunction or operator error before or during treatment, visual and audible alerts either prompt the operator to take appropriate corrective action or cut off devices ensure that the microwave power is switched off. Temperature and power indications are displayed graphically in real time on a colour display at user eye-level. A printer is used to provide a hard copy of the treatment profile for the patient's file.