In Situ Spinal Fusion

How bone graft is used for In Situ spinal fusion

Bone graft is used to correct issues with bones and joints, the surgery is also referred to as bone tissue transplant. Bone grafting is essential especially to create stability in cases such as knee transplants for example which helps to allow the bone to grow around an implanted device.

The two main types of bone grafting include:

- An Allograft - bone from a cadaver or deceased donor is used,

- An Autograft - these bone grafts come from the patient's own body (hip, wrist, pelvis or wrist).

There are also other types which are sourced differently and more common in dentistry such as:

- Synthetic variants - made from ceramics to mimic true bone,

- Xenograft - from cattle (bovine),

- Alloplastic grafts - from natural metal.

Spinal fusion surgery is sometimes performed to stop the spine from growing. The operation can be completed through the chest (anterior) or through the back (posterior). In the procedure, the joints of the spine are taken out and are replaced with a bone graft. As the bones heal, they fuse together to form one solid mass of bone. The goal of the surgery is to make several of the individual backbones (vertebra) become one section and stop growing crooked or curved out of alignment. Sometimes surgical implants such as screws, rods or hooks are inserted to act like an internal brace for the bones and the bone graft and to help slightly straighten the spine. In young children, implants might not be used, and the child may need to wear an external brace following surgery.

Patients may also need a bone graft if they have a bone disease, an injury that has not previously been treated, surgically implanted devices as well as a fracture that may not be able to heal without a bone graft procedure.

Advantages of bone grafts

The advantage of an in situ spinal fusion is that it can address the problem of a spinal curvature early before serious deformity occurs. For instance, if a spine specialist sees a child who has a 40-degree curvature that has a good chance of progressing, a limited spinal fusion may be recommended to prevent the curve from getting any worse.

In situ spinal fusion usually carries less risk than operations to correct a spinal curvature. The outcome of surgeries performed to correct curvatures on patients who are still growing is difficult to predict. This is because the spine is still growing, and as it grows in areas not affected by the curve, rotation or twisting of the spine can occur.

Spinal fusion is not recommended for every patient diagnosed with early onset scoliosis. It stops the growth in one section of the spine, so it can also prevent or slow the growth of the thorax, the part of the body that lies between the neck and the waist. This can cause thoracic insufficiency, a condition in which the walls of the chest cannot support adequate breathing.

Risks of bone grafts 

Bone grafting is a surgical procedure and even though it has many benefits it also poses risks which can be also expected from any surgical procedure or operation. Some of these risks may include:

- Bleeding,

- Infection,

- Infection from the donated bone or bone tissue source (rare),

- Complications due to anesthetic,

- Inflammation/swelling,

- Rejection of the bone graft,

- Nerve injury.

Symptoms and Diagnosing the need for bone graft surgery

Treatment of spine using bone grafts

Instrumented Fusion and Osteotomy

When older children develop progressive kyphotic curves, surgery may be performed that includes the use of instrumentation such as screws, hooks, and rods, to help correct the condition. If the risk to the spinal cord it too high to consider manipulative techniques to correct the curve, the surgeon sometimes will remove the vertebrae that are misshapen in order to straighten the spine.

In some cases, surgeons recommend an osteotomy, which involves cutting the bones in order to re-align the spine. Sometimes the bone is removed from the back of the vertebrae to allow the bone to collapse backward. This procedure is called a pedicle subtraction osteotomy. In vertebral column resections, the back and the front of the vertebrae are resected through an incision made in the back. Surgeons sometimes recommend different procedures be performed from both the back and the front of the spine.

Taking care after a bone graft procedure

Many patients will experience pain, this is only natural after any surgical procedure. Recovery time after a bone graft for spinal fusion can vary one patient to another but children will naturally heal faster than adults and elderly patients. Often a back brace is worn to limit movement during the healing process and the patient will need assistance and care within their home.

The patient will be prescribed medication to follow after the bone graft procedure and will need to complete any antibiotics course prescribed. The patient cannot overexert themselves during healing time.

You might also want to read:
- Corpectomy,
- Discectomy.