There have been some questions, recently, regarding the difference between “temporary” and “permanent” feeding tubes. Whichever tube is chosen, they both require either eventual removal or replacement:
1) temporary tube – long tube (6-12inches) placed through the body wall into the stomach; usually placed using an endoscope. Can be used for 2 weeks (that’s why this tube is called “temporary”) to several months. If needed longer, a “permanent” tube can be placed; requires anesthesia for placement.
2) permanent tube – “low profile button” laying up against the body wall, to which a longer tube can be attached for feeding; can be placed either by removing a temporary tube which has been present for at least 2 week, or, can be placed surgically by opening the abdomen. Usually requires either no sedation, or, mild, short term anesthesia.

For more information, see:http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=3504

This is from a different source:
“There may be a slight misunderstanding as to the meaning of “permanent” versus “temporary” feeding tubes. Technically, these terms generally mean how long you rely on the tube for feeding your dog. There are two general procedures for placing a gastrostomy tube, or at least, two common ones. One is done with a scope, and a short term anesthesia. It is not “surgery”. A small puncture is made on the outside of the dog’s body in the lower side of the midsection, close to the stomach. Then the tube is inserted from the outside, through the body wall into the stomach, and the stomach end of the tube is placed to hold the stomach firmly against the inner body wall, so that leakage from the stomach into the peritoneum will not occur. The first 10-14 days are very important to avoid ANY disturbance of this connection, with the tube in place, so that the new “mouth” (called a stoma) from the outside of the body to the stomach, can heal and close firmly around the tube, and the stomach well-adhered to the inner wall of the body. This tube is generally what is referred to as the “temporary tube”, although well cared for, may last many, many months. Once the body has healed in this manner, a low profile tube may be inserted, and that is a simple procedure, usually requiring no anesthesia at all, but may need only sedation for an uncooperative dog. The tube is fed through the opening, and once the far end of the tube is in the stomach, the balloon is inflated, either with about 5 cc of water, or air, depending on tube design. That probably takes 10 – 20 minutes. The low profile tube generally lasts 6 – 12 months, and is also changed in the same way. Many dog owners keep an extra low profile tube on hand, just in case. They can be purchased online, and cost roughly from about $150-300. You have to know the size.

Once the stoma is well healed, replacement is pretty simple, but a damaged or expelled tube has to be replaced quickly, because the body tries to close that opening right away, and after about an hour, this may require a bit of help at the DVM clinic. So – what is a “permanent tube”? That is when the first tube is placed surgically, with a low profile tube as the initial placement. Or, some refer to the low profile tube as being “permanent”, even when inserted as discussed about, after the “temporary” tube. It is more invasive, more expensive, and harder on the dog. I will leave explanation of this part to Dr. Kathy, as my experience is with the first process, then placement of the low profile. The most important thing is the doctor’s proper assessment of the size (think straw versus cocktail mixer straw) and length of the part of the tube that goes from outside to the stomach, and the proper size of the “hole” to punch for it.

The first, so-called “temporary” tube has a few inches of tubing that you see outside of the body, with the feeding valve on the end, and is a little easier to use because you aren’t going directly into a tube close to the dog, so positioning is less crucial. To confuse matters, there are adaptors that can hook into a low profile tube, and make them more like the temporary PEG tube, for ease of use.

The first two weeks one will be a bit nervous about getting used to handling this, and cleaning the stoma, and keeping the dog away from the tube completely.

A feeding tube can be removed when no longer needed, but not in the first two weeks. That would be potentially dangerous.”