Jeff
First off I will get to the basics, since I really don't know how much you know about all this. The vertebra are the bones in your spine, and the disk are more or less pads of cartilage that sit between the vertebra, these cartilage pads a tough on the out side, ( kind of ruberry and some what flexible, and they are soft in the inside, like a jell) they cushion the vertebra and make the spine flexible. As one ages these disk can become a bit brittle and they lose some of theit elasticity. Thus when stressed they can bulge out and not go back to their regular shape. When this happens that bulge can press on the spine or the nerves coming off the spine, allot of times this bulge will eventually dissappear on its own the disk will just slowly go back to its original shape. If it doesn't then the doc can do things to help relieve the pain and or fix it. An actually herniated disk or disk rupture is when the outside hard rubbery part tears or cracks and the inside jelly part spills out, and presses either into the spinal cord, or the out branching nerves, this is usually fixed by the doctor doing surgery. A disk fusion is when the doctor usually goes in and removes the disk and cleans and roughs up the surfaces of the vertebra above and below the removed disk, and then puts in a bone material ( they can either use grafts of your own bone,{ my fist fusion they took bone from my pelvis and used for the graft material}, or they can use donor cadaver bone,my second fusion) I have had both, the bone material is put in the space where the disks once was , and over time the bone will grow and become a part of the vertebra above and below and fill in the area where the disk once was. Thus you have one big bone area where you once had two vertebra and a disk. This can take away some of the mobility of your spine, especially if you have more than one fusion done in a row, say C-4-5-6 all fused together. this would then make this just one large bone and thus no flexion.
Anyway most fusions done now days they ususally use donor bone for the graft, I think it is easier on the patient, as when I had my first fusion they took the bone from my pelvis and that area hurt more that the fused area. Anyway when they do that, they cut through the front part of your neck and they move everthing to the side so they can get at the bad disk, then the surgeon removes the disk, and after they remove it, and clean it all out, they insert a cage like thing containig the the ground up bone material ( at least that is how it was explained to me) and they put this in between the two vertebra where the bad disk was, ( this is the bone graft material that will grow and fuse the top and bottom vertebra together) then they will usually put a bracket across the front of it, to hold the top and bottom vertebra together, and keep everything in place! They anchor this bracket with titanium screws, two that are screwed into the top vertebra, and two screwed in the bottom vertebra. This gives stability until the bone has a chance to grow and fuse the vertebra together. Allot of times when they are doing this, they will shave any excess bone off, ( such as bone spurs that are pressing on the spinal nerves) and they make sure that the nerves are clear and nothing is pressing or impinging on them. The reason that this surgery works is because they remove the part that is pressing on the nerves, when that is gone so usually goes the pain.
When I had my fusions, all I had was arm pain, it was excruciating, it was like when you severly hit your crazy bone, and it went down into my hands and it burned like fire, and ached and .......well it just hurt like the dickens! but the damage was not in my hand or arm it was all in my neck in that C-6/7 disk! and 25 years later I had similar pain again, but affecting different fingers, and kind of down a little different part of the arm. and that time it was C-5/6 this last time the pain was primarily down my left arm, but the first time it was in both arms. Anyway this last fusion I had in Sept of 2009 it was a C-5/6 ACDF, A is for:= Anterior ( going through the front of the neck for surgery) C=Cervical ( the the disks in your neck are Cervical disk) D=Diskectomy ( that is where they take out part or all of the disk that is bad) F=Fusion ( that is where they put in the bone {yours or donor cadaver bone} to fuse the top and bottom vertebra together)
This last time I was in the hospital for 3 days I went in early Monday morning and had the surgery, and I woke up in the afternoon in my room and my arm pain was completely gone! The had a little tube coming from my neck into a J-vac drain( it drains off excess fluid from the surgery and prevents fluid build up and pressure in the fusion area) and they pulled that out on Wednesday morning ( not they don't always put a drain in, it is up to the surgeon that does it) anyway right after that I was discharged home! I had a soft cervical collar brace on for two weeks. and had to go back and get the stiches out in two weeks and then a follow-up in another 6 weeks. with X-rays. It really was not that bad, and to get rid of the arm pain I would do it again with no problem! Just make sure you follow your doctors orders! that is a must to avoid complications!
I hope this has helped you, if there is anything I can be of help with, just let me know
Good Luck to You
White Beard