Understanding your spine and surgery.

How the spine is built

The spine, or vertebral column, is a flexible column of 33 bones called vertebrae. It supports the body, allows movement and protects the spinal cord. It runs from the base of the skull to the tailbone and is divided into five regions:

• Cervical (7 vertebrae) — the neck. They allow a wide range of motion, including bending, extending and turning the head.
• Thoracic (12 vertebrae) — the chest. They connect to the ribs and help protect the heart and lungs.
• Lumbar (5 vertebrae) — the lower back. The largest and strongest vertebrae, they carry the weight of the upper body.
• Sacrum (5 fused vertebrae) — a triangular bone at the base of the spine that joins the pelvis.
• Coccyx (4 fused vertebrae) — the tailbone.

Between the vertebrae are intervertebral discs, made of cartilage, which act as shock absorbers and allow movement. The spinal cord, a long bundle of nerves, runs through the centre of the column and carries messages between the brain and the rest of the body.

Why spinal surgery may be needed

Surgery is usually considered when pain, weakness or instability does not improve with other treatment. Common reasons include worn or damaged discs (degenerative disc disease), a vertebra slipping out of place (spondylolisthesis), pressure on nerves or the spinal cord, fractures, and deformities such as kyphosis.

Common procedures

Spinal fusion

Fusion joins two or more vertebrae so they heal into a single solid bone. Screws placed in the vertebrae (pedicle screws) are connected with rods to hold the spine still while it heals. An interbody cage may be placed in the disc space — from the back (PLIF) or from the side of the spinal canal (TLIF) — to restore disc height and hold bone graft.

Anterior cervical discectomy and fusion (ACDF)

In the neck, the surgeon removes a damaged disc from the front, places a cage in the space to hold the vertebrae apart while they fuse, and may add a small plate. Standalone cages combine the cage and fixation in a single implant.

Balloon kyphoplasty

For painful compression fractures, often caused by osteoporosis, a small balloon is passed into the fractured vertebra through a narrow tube and inflated to restore height. The balloon is removed and the space is filled with bone cement to stabilise the bone.

Questions to ask your surgeon

• What is causing my symptoms, and what are the non-surgical options?
• Which procedure do you recommend, and why?
• What are the risks and expected benefits in my case?
• What will recovery and rehabilitation involve?