My thoughts on this can be summed up with "I wouldn't recommend it". Though I haven't seen your stats, it's obvious that the size of your penis is a sensitive topic to you, but what you have to realize is that surgery -- any surgery -- carries risks. I admit, I'm nowhere near an expert when it comes to the field of medicine, but it's an area I know a thing or two about, at least, so believe me when I say you shouldn't make this decision lightly.
From what I understand, the surgery involves the cutting of the suspensory ligament of the penis. The ligament is then either extended and reconnected with an artificial bridge or is simply allowed to heal. Both methods result in a longer penis, but remember that the penis isn't just a ligament. It's also blood vessels, nerves, skin, and so forth. You can't be sure how much you'll actually gain until you undergo the surgery, and if it ends up that, say, your nerves or certain vessels don't go as far as you hoped they would, you end up with a very slightly longer penis and a pretty sizable medical bill.
Apart from that, you also must remember that surgery in general can be pretty risky. Surgery opens up the body to a whole slew of problems, including incomplete vascular regeneration, odd nerve growth, nerve disconnection, scar tissue buildup, infection... The list goes on for much longer than that, and I assure you that no item on said list is all that pleasant.
At the end of the day, the decision is still up to you. If the length of your penis bothers you enough that you're even considering elective surgery for it implies that it's pretty important to you. Personally, I would recommend speaking with someone about it - I've heard tales of sex therapists that have truly helped people overcome their sexual insecurities. Even if you do end up going through with it, then you can make the decision knowing exactly what you're getting into.
I wish you nothing but the best!