A large number of different conditions can affect the anal region, and some of these conditions require surgery as a form of treatment.
The most common operation is hemorrhoidectomy for piles. A small amount of skin, inner lining of the anus and the piles tissue which consist of an abnormally swollen blood vessel is cut off. This is usually done with an electric knife. Most people have 3 piles, and all 3 are removed at the same operation. However, if the operation is done when the piles are very swollen or when there are many piles, your surgeon may choose to leave some smaller piles behind. This is to avoid cutting too much skin, resulting in a very narrowed anus and causing difficulty in passing motion.
Other common operations include drainage of abscesses. For drainage of abscesses, the skin is cut open. The wound is not stitched back together, so that any pus left inside is allowed to drain out.
For treatment of a fistula, the tract is cut open, taking care not to cut too much of the anal muscle. If there is a risk of cutting too much muscle, your surgeon may choose to leave a stitch inside first and do a second operation to cut the muscle later.
For anal fissures, the anal muscles at the side may be cut to relieve the tension and allow the fissure to heal. Your surgeon will take great care not to cut too much muscle and cause incontinence.
Anal muscle repairs surgeries are also done for incontinence. Most commonly, the muscles are cut apart, overlapped and tightened, and then stitched back together.
Most of these operations are done under anaesthesia. This may be general anaesthesia, where you are asleep, or regional anaesthesia, where you are given an injection at the back and will be numb over the area of the operation.
In some operations, your surgeon may decide that a local injection (local anaesthetic) will be adequate.