Spinal Fusion

This is a descriptive term for what is often part of a spinal operation. A fusion is when the moving joint between two bones is removed and the bones become joined up. This has the effect of stiffening the joint that is fused. In the spine, because there are so many mobile joints, the patient may not be aware of stiffness if one or two joints are fused. If more bones are fused in mobile areas of the spine some stiffness may be noticeable.

A spinal fusion is commonly carried out as part of a spine operation. The patient’s own bone may be used as a bone graft, sometimes artificial bone is used or sometimes a metal or other type of material is used as a cage between the bones.

In many operations, such as a spinal decompression, bone is removed to free up the collapsed space around the nerves. As well as a decompression the spine may be fused to stabilize the spine at that site. Essentially a solid fusion between two vertebra means there is no bone on bone movement at this level. If abnormal movement has been part of the pain generator then fusing the spine may sometimes help improve the pain.

In some operations such as scoliosis surgery, quite a long area of the spine may be fused to lock it in the corrected and better position. It is important that if spinal fusion is planned, that the fusion aims to achieve a normal alignment of the spine. Increasing levels of fusion, particularly in the lumbar or cervical spine can signify increased risk both during and after the procedure.

Stabilisation

This is a term sometimes used along with the words spinal instrumentation. It is where the area to be fused is also fixed with an implant device. These will usually be a rigid system of screws and rods to reduce movement and possibly improve the probability of a solid fusion occurring. Spinal implants are subject to stringent quality control in terms of the use of medical grade metal and manufacturing process. The implants, screws, rods or possibly hooks are usually made of titanium so that MRI scan can occur if needed.

In discussing the specifics of your spinal surgery your surgeon should give you all the information you wish to know. The options of not fusing and not using implants should also be discussed, so that shared decision-making and good understanding occurs.

When the spine is mechanically unstable as a result of fractures or bone loss from tumours, stabilising the spine with a scaffold of metal will enable an earlier return to walking and reduce the risk of the spine displacing and becoming painful.

Surgery for scoliosis will usually involve stabilisation of the spine with screws and rods to hold the spine in a realigned position until bone healing and fusion has occurred.

Disc replacement

Disc replacement is an operation that is meant to preserve movement. It requires careful evaluation in terms of pre- operative tests and imaging as many patients are not suitable for the procedure. In the lumbar spine it is sometimes offered for severe back pain that has not improved despite all the non-operative treatments that are often effective. A CT scan is often done to exclude arthritis of the small facet joints of the spine, as if there is arthritis in these joints the operation is not likely to be helpful.

A disc replacement for the lower back requires the operation to be performed on the front of the spine through the abdomen. Usually there is also a specialist vascular surgeon assisting who is familiar with operating on and around the blood vessels in the abdomen.

There are artificial discs for both the lower back as well as the cervical spine. Disc replacement in the neck is also done from the front.

Initial results have shown very good improvement with symptoms but over time, the long-term results do not seem much different to a spinal fusion for back pain.