Lumbar Spinal Fusion Surgery

What is Lumbar Spinal Fusion Surgery?

Lumbar spinal fusion is a surgical technique in which one or more of the vertebrae of the spine are joined together (fused), to maintain their separation and alignment, and to stop them from moving against each other. This is done by placing bone grafts or bone graft substitutes between the affected vertebrae. The graft material acts as a binding medium and also helps to maintain normal disc height (see under “Disadvantages of Discectomy” in the foregoing). As the body heals, the vertebral bone and bone graft eventually grow together to join the vertebrae and stabilize the spine.

Why Might I Need This Procedure?

There are a number of reasons your surgeon may recommend spinal fusion. This procedure is frequently used to treat

One or more fractured (broken) vertebrae
Spondylolisthesis (one vertebral bone slipping forward on another)
Abnormal curvatures of the spine, such as scoliosis or kyphosis
Protruding or degenerated discs
Instability of the spine (abnormal or excessive motion between two or more vertebrae)

Most commonly fusion is advocated because the decompression operation which must be done to alleviate compression of the spinal cord or nerve roots would destabilise the spine. Fusion, performed as the second stage of the operation, restores alignment, curve and stability to the spine.

Prof. Brazenor will always explain your non-surgical option (if there is one) as well as the surgical option along with its success rate, failure rate and risks. Except when cancer or dangerous spinal instability is present, it is always Prof. Brazenor’s advice that if you are then not sure about having surgery, you should choose not to have surgery for the moment. Stop, think, and let some time pass, and the correct way for you to manage your condition will become clear.

How Is Spinal Fusion Performed?

There are a variety of surgical approaches and procedures, but all involve the placement of bone graft material between vertebrae. The graft material may be bone - either taken from the patient (autograft) or from a bone bank (allograft) – or a synthetic bone substitute called bone morphogenetic protein (BMP).

The various types of fusion are explained in the pages following, including:

Prof. Brazenor will advise you as to which fusion method (if any) is best for your particular condition, should you finally have to resort to surgery.

Spinal Fusion: Traditional vs. Minimally-Invasive Approach

Traditionally, surgeons have performed spinal fusion as an open procedure, which involves making an incision, stripping bands of muscle and retracting muscle and tissue for a clear view of the spine and easy access to the vertebrae for implantation.

Modern spinal fusion can under some circumstances employ less invasive surgical techniques, such as muscle dilation, making the highly invasive posterior fusion approach unnecessary in many cases.

Muscle dilation is achieved by using a series of sequential dilators, or tubes to separate the fibers of the back muscles and create a small tunnel, enabling the surgeon to view the spine through a much smaller incision, with much less disturbance of the spinal musculatureleaving the muscle virtually intact. Advances in instrumentation allow rods and screws to be inserted via smaller incisions in the skin.

Bone graft

Traditionally, autograft has been “the gold standard” in graft material. However, removal of the bone – usually from the patient’s pelvis or iliac crest – can be very painful. Allograft (graft taken from human donors) does not require this extra procedure, but many studies show that the fusion rate with allograft is less than the fusion rate with the patient’s own bone. Prof. Brazenor specialises in using every skeric of your bone as it is drilled away during the approach to your spine (this is termed “local bone”), and very rarely has to take bone from another site.

Bone Morphogenetic Protein (BMP), a naturally-occurring human protein important in bone growth and now made in the laboratory, is now frequently used to speed the process of boney fusion, and to increase the likelihood of fusion occurring. BMP can even be used in some situations to replace bone graft entirely. Unfortunately BMP is expensive, and can cause temporary inflammation of nerve roots, and swelling of soft tissues.