I received a question from someone seeking unusual ornamentation:
Are surface anchor piercings permanent, and can you get them on your feet (top)?
No, unfortunately, even when everything is done right, surface anchors simply appear to be less of a permanent body modification than traditional body piercings.
Further, they require ongoing care throughout their life span, including regular irrigation to make sure no matter builds up in the channel or under the ornament. And even with this care, sometimes they will tilt and/or surface and reject.
On the feet, they are especially unlikely to be successful, even for a short period of time. There is little padding on top of the bone, and the area is subject to excessive trauma. Also, in that region you are at greater risk for infection than other parts of the body because of the proximity of the feet to the dirty ground.
In the event that a surface anchor were to actually heal and stay for longer than I would expect, there's some chance that a small amount of tissue could grow through the holes that are present in the base of most anchors (for the very purpose of helping the anchor remain in place). If that were to happen, it could still be removed by a piercer using ordinary piercing instruments.