During this procedure, the surgeon permanently joins two or more vertebrae in the spine. The vertebrae will grow together to form a single, solid bone. Spinal fusion is commonly performed in the neck and lower back, and may be used to correct a wide range of problems in the spine. This animation shows a fusion in the lumbar spine to correct a condition called spondylolisthesis, in which weakened joints or fractured bones have allowed a vertebra to slip forward and pinch a nerve root.
Spondylolisthesis is a displacement of one of the bones of the spine. When the displaced vertebra slips out of its normal location onto the bone beneath it, it may compress a spinal nerve, causing pain. This condition most commonly occurs in the lumbar (lower) region of the back. For some patients, lumbar spinal fusion surgery may be necessary to correct spondylolisthesis.
Causes of Spondylolisthesis
Spondylolisthesis is a condition in which a defect in part of the spine causes a vertebra to slip out of position and onto the bone beneath it. The condition usually occurs between the fifth bone in the lower back, known as the lumbar vertebra, and the first bone in the sacrum, or pelvic, region.
Spondylolisthesis may occur due to a variety of factors including the deterioration of spinal joints that takes places during the aging process when arthritis is present. The condition may also result from an infection, congenital malformation or stress fracture, which can damage a bone so badly that it is unable to maintain a solid position and begins to shift out of place.
When it develops in younger individuals, spondylolisthesis is most likely to be found in those who participate in certain sports activities such as gymnastics, diving, wrestling or weight lifting. These athletic pursuits can place excessive stress on the lumbar spine, which may eventually result in injury. Genetics are another potential cause of spondylolisthesis, as some patients are born with thin vertebral bones that may make them more vulnerable to developing the condition. Spondylolisthesis may also occur in older patients who have a degenerative condition such as arthritis, which can wear down the bones or cartilage over time.
Symptoms of Spondylolisthesis
The severity of spondylolisthesis symptoms is quite variable. Patients with spondylolisthesis may be completely asymptomatic or may experience symptoms ranging from mild to extremely serious. The most common symptom is typically pain across the lower back, which becomes progressively worse following strenuous exercise. Other symptoms of the condition may include:
- Muscle weakness or tightness
- A tingling sensation in the thighs or buttocks
- Extreme tenderness at the slippage site
Diagnosis of Spondylolisthesis
Spondylolisthesis is diagnosed through evaluation of a medical history, a thorough physical examination, and detailed X-rays of the spine. When the patient has pain when raising a straightened leg, this may be indicative of the disorder. Spinal X-rays will help the physician to detect fractures or misalignment of vertebrae.
Treatment of Spondylolisthesis
Treatment for spondylolisthesis will depend on the severity of the slippage. Initially, conservative forms of treatment may be employed for mild cases of the condition, including wearing a back brace to limit spine movement, the use of anti-inflammatory pain medication and beginning a course of physical therapy. If the slippage of the vertebrae is severe, or if nonsurgical treatments fail to provide any relief, lumbar spinal fusion surgery may be necessary.
The Lumbar Spinal Fusion Procedure for Spondylolisthesis
Performed under general anesthesia, lumbar spinal fusion for spondylolisthesis involves the joining of two or more vertebrae in the lower spine using a bone graft to prevent the bones from slipping. This technique enables the two bones to grow together, forming one stable bone. In some cases, metal screws and rods will be implanted to provide support and hold the vertebra in the proper position as the fusion takes place.
Risks of Lumbar Spinal Fusion for Spondylolisthesis
As with any form of surgery, there are several possible complications associated with a lumbar spinal fusion procedure. The risks may include:
- Failure of the vertebrae to fuse together properly
- Failure of the hardware used in the procedure to hold the vertebrae together correctly
- Blood clots
- Pulmonary embolism
- Numbness or weakness throughout the body
- Persistent back pain or stiffness
- Nerve injury
Recovery from Lumbar Spinal Fusion for Spondylolisthesis
After undergoing a lumbar spinal fusion procedure to treat spondylolisthesis, the patient will usually need to participate in rehabilitation services to help promote healing and allow the bones to fuse together. Rehabilitation usually lasts for approximately 6 to 8 weeks, and most patients can expect a full recovery after about 6 months.