Thoracic spinal fusion: why it is done, risks and recovery

The thoracic spine is the mid-back section of 12 vertebrae to which the ribs attach. Spinal fusion is an operation that deliberately joins vertebrae so they grow together into one solid piece. The Royal National Orthopaedic Hospital (RNOH) describes it as a procedure to stabilise two or more vertebrae of the spine using metalwork and bone graft, either from your own body or synthetic bone. The screws and rods act as a scaffold, enhancing the body's ability to build new bone between the vertebrae.

Most of the NHS leaflets available describe lumbar (lower back) fusion or fusion for scoliosis. This page draws on the Cambridge University Hospitals leaflet on surgery for scoliosis in people over 16, which describes fusion of the thoracic and lumbar spine, and the RNOH guide to lumbar fusion for the general principles. Details for an individual depend on the part of the spine, the reason for surgery and the surgeon's technique, so your own team's information takes precedence.

Cambridge explains that adolescent idiopathic scoliosis affects children aged 10 to 18 and is found in as many as 4 in 100 adolescents, that curves can continue to progress in adulthood, especially those greater than 60 degrees, and that surgery is considered when there is a risk of the curve progressing or when it has progressed beyond 40 degrees. Approximately 1 in 4 patients with scoliosis will require surgery, according to the leaflet.

RNOH describes the suitable patients for fusion in general as those with incapacitating back and leg pain from deformity (abnormal spinal curvature) or instability (excessive displacement of the spine), and says it is generally a last resort after conservative measures. Other reasons for thoracic fusion, such as fracture or tumour, are decided on an individual basis by a spinal surgeon.

Cambridge describes positioning you to correct the curve, an incision down the middle of the back, screws inserted on both sides of the spine, and two metal rods that hold the correction in place. Bone graft is then added, which causes the vertebrae in that part of the spine to fuse together. The operation normally takes four to five hours, although you may be in the operating theatre for most of the day.

RNOH explains that fusion in the lower back can be done from the front through the abdomen, from the back, or from the side. Surgery is usually under general anaesthetic, and before it you attend a pre-assessment with blood tests and other checks, and are asked to stop smoking or vaping for a minimum of 6 months beforehand.

Cambridge lists blood loss, which may need a transfusion, and the main risk of damage to the spinal cord, which can result in paralysis of the legs and loss of bladder and bowel control. It says this is rare, occurring in about 0.5 per cent of cases worldwide, and that spinal cord monitoring is used. Other risks include damage to the main blood vessels near the spine, wound infections that sometimes only appear months or years later and may require metalwork removal, loosening or failure of screws and rods, and a large scar that fades over about six months.

RNOH adds to its list: anaesthetic risks, nerve injury, bowel injury, cerebrospinal fluid leak, increased pain, failure of fusion, failure to improve symptoms, metalwork failure, adjacent segment disease and deep vein thrombosis, for which stockings and inflatable leg sleeves are used. It says most of these risks are rare and should be discussed thoroughly with your surgeon. It also notes that more than 50% of patients experience improvement in back pain and 50 to 80% in leg pain after lumbar fusion, a statistic that applies to that operation rather than scoliosis surgery.

Cambridge says that after surgery you will be monitored in intensive care, high dependency or on the ward with drains and a bladder catheter, and that it should be possible to get out of bed on day one. Patient-controlled pain relief is used, and physiotherapists help with breathing exercises, circulation exercises and mobilising. Patients are normally ready to leave hospital from four days after surgery and should be able to return to college or work in four to six weeks, increasing activity gradually.

RNOH describes planning for the first six to eight weeks at home: removing trip hazards, arranging help with shopping and care of dependants, and planning time off work. Regular X-rays after the operation check the metalwork. Because the spine is weaker until it has fused, follow your surgeon's and physiotherapist's advice on lifting, bending and sport.

Complex spinal surgery on the NHS is delivered through spinal deformity and spinal surgery units after multidisciplinary discussion, and Cambridge notes the waiting list can take several months. Private spinal surgery is available, but because of the size of the operation it is worth asking about the surgeon's experience with your specific condition, spinal cord monitoring, intensive care support and long-term follow-up with X-rays.