Fardh ghusal for a person who has a medical device taped to his skin

There is a device on the market which is attached to the skin. It gives you a continuous and real time reading of your blood sugar levels by which a diabetes patient will know when to take his insulin and how much insulin he should take. (Not over or under administering the medication)

The device is quite expensive (removing & changing the device each time you require a farz ghusal will be very costly). The device has an adhesive tape by which it is attached to the skin thus preventing water from reaching underneath it. Will the farz ghusal of a person wearing such a device be valid if he makes masah only over the device and washes the rest of the body?