External adjustment device for distraction system

A method for distraction of bones comprising the steps of:

• providing a distraction system comprising:
• a distraction device configured to be implanted within a subject's body and having an adjustable portion for adjusting a dimension of the distraction device;
• and
• an external adjustment device configured to be placed external to the subject's body in proximity to the distraction device to cause distraction of the distraction device, the external adjustment device including:
• at least one permanent magnet configured for rotation about an axis;
• an actuator configured for rotating the at least one permanent magnet about the axis;
• a control panel configured to control actuation of the actuator;
• and
• at least one sensor in proximity to the at least one permanent magnet,
• wherein the at least one sensor is configured to sense a magnetic field of the at least one permanent magnet as the at least one permanent magnet rotates about the axis within the external adjustment device,
• wherein the at least one sensor is configured to output a first time-variable voltage based at least on a time-variable strength of the sensed magnetic field corresponding to rotation of the at least one permanent magnet,
• distracting adjacent bones using the distraction system.