Spinal Fusion

The spine is made of vertebrae separated by discs and linked by small facet joints, which together allow bending and twisting. When a segment becomes unstable, painful or deformed, fusing it removes motion at that level. In most modern fusions the surgeon first places screws into the strong part of each vertebra, called the pedicle, and connects them with rods to hold the bones still. Often the worn disc is removed and replaced with a cage, a spacer made of titanium or a strong plastic, which restores the height between vertebrae and gives the bone graft a large surface to grow across. The graft may be your own bone, taken from the spine during surgery or occasionally from the pelvis, donor bone, or a synthetic bone substitute. The screws and rods are a temporary support: the long-term strength comes from the bone growing into one solid piece, which usually takes 6 to 12 months.

Fusion is recommended for problems where movement or instability is clearly part of the cause. Common indications include degenerative or isthmic spondylolisthesis, in which one vertebra slips forward on the next, spinal stenosis that requires extensive bone removal or occurs with instability, and deformities such as scoliosis or kyphosis in adults. Fusion is also used after spinal fractures, for some infections and tumours of the spine, and in the neck, where removing a disc that presses on the spinal cord or a nerve is usually followed by fusing that level. When the only complaint is back pain from general disc wear, without instability or nerve compression, the evidence is mixed: some patients improve after fusion, while others do as well with a structured rehabilitation programme. A careful assessment, including an honest discussion of alternatives such as physiotherapy, spinal injections or decompression without fusion, should come before any decision. Getting a second opinion before fusion is reasonable and common.

Spinal fusion is performed under general anaesthesia, and the approach depends on the problem and the level of the spine. In the lower back, the most common route is from behind, with you lying face down: the surgeon frees any trapped nerves, places pedicle screws and rods and, in techniques known as TLIF or PLIF, inserts a cage into the disc space from the back. Other routes reach the disc from the front through the abdomen, called ALIF, or from the side, called lateral fusion, sometimes combined with screws placed from behind. In the neck, the usual operation is anterior cervical discectomy and fusion, done through a small incision at the front of the neck. Minimally invasive techniques place screws through small skin cuts, and image guidance, navigation or robotic systems can help position them. Nerves are monitored during surgery in many centres. One level usually takes about 2 to 4 hours, and longer constructs take more time.

Good candidates have a clear structural diagnosis that matches their symptoms, such as instability seen on standing or bending X-rays together with MRI or CT findings, and have usually tried non-surgical treatment for several months unless nerve damage or a deformity is progressing. Your general health matters a great deal. Smoking and nicotine in any form strongly reduce the chance of the bone fusing, so stopping well before surgery is often required. Diabetes should be well controlled, weight optimised where possible, and bone strength checked with a density scan if osteoporosis is suspected, because weak bone holds screws less securely. Before surgery you will have blood tests, an ECG and sometimes heart or lung checks, and blood thinners are paused on medical advice. For international patients, scans and reports can usually be reviewed remotely before travel, so that the plan, including the levels and approach, is largely agreed before arrival.

Most people are helped out of bed within a day of surgery and walk short distances with a physiotherapist. Pain is managed with a combination of medicines, and the hospital stay is usually two to five nights, longer after multi-level or deformity surgery. A brace is used by some teams. For the first 6 to 12 weeks, bending, lifting and twisting are limited, while walking is encouraged and increased each day. Desk work often resumes after about 4 to 6 weeks, and physically demanding jobs may need 3 to 6 months. Driving usually becomes possible after a few weeks, once you can sit comfortably and are off strong painkillers. For travel, plan to stay about 10 to 14 days, or longer after larger operations, so the wound can be checked and an X-ray taken if needed; your team will advise on preventing blood clots during the flight. Rehabilitation then continues near home, with follow-up X-rays at intervals to confirm fusion.

Spinal fusion is an established operation, but it is major surgery with real risks. These include infection, bleeding, a tear in the membrane around the nerves, nerve injury that can cause numbness or weakness, blood clots and, rarely, problems with the screws or cage that need further surgery. Sometimes the bone does not fuse fully, called non-union, which is more likely in smokers and people with diabetes or weak bone, and may cause ongoing pain or loosening of the implants. Over the longer term, the discs and joints just above or below a fusion take on extra load and can wear faster, known as adjacent segment degeneration; over the years a proportion of patients develop symptoms at those levels, and some need a further operation. Results depend strongly on the reason for surgery. Leg pain from nerve compression and instability usually improve more reliably than back pain from disc wear alone. Stiffness from a one- or two-level fusion is rarely noticeable in daily life.