I've done a little searching about erosion, but I didn't quite get the info I was looking for. What is it, what are the symptoms and what can cause it?

My understanding (which may or may not be right) is that erosion is when the band starts to "eat into" and wear away the wall of your stomach. Think of wearing a wristband too tight, or the way a really tight wedding ring eats into your finger or a too-tight collar on a cat or dog will eat into their neck. As far as I know, the major cause is having the band too tight or overeating constantly and putting extra pressure on the band.

This is different from slippage, which is where part of the stomach from below the band slips up through it and then swells up, closing your stoma. That is usually caused by the band becoming detached from where it was stitched to your stomach wall, usually from excessive vomiting causing the stiches to tear loose.

Apparently erosion often doesn't have that many symptoms until it has progressed quite a way and become quite serious. If it wears all the way through the stomach, it can be very dangerous and often requires having the band removed altogether. Slippage is more easily detected (pain, acid reflux and not being able to swallow water) and is also more easily fixed (if caught early, a liquid diet until the swelling goes down can make it slip back down on its own, or a simple readjustment surgery if it has gone further).