Nobody really wants to lose spine motion, but sometimes spinal fusion is the only way to get rid of pain and hold the problem part of the spine together. If one or more segments of the spine must be fused, what’s the best way to do it? What method gives the best result?
This is the focus of a recent study from Japan. The researchers looked at 19 cases of degenerative spondylolisthesis. In spondylolisthesis, there is a fracture in one of the columns of bone supporting the vertebra. The body of the damaged vertebra slips forward over the vertebra below it. This condition causes many problems. Holding the bone in place is important. Screws and bone graft are often used to do this. The result is called a posterolateral fusion.
A newer method of fusion for spondylolisthesis is the posterior interbody lumbar fusion (PLIF). PLIF uses devices that look like cages. Cages are made of titanium, bone, or graphite and fit between the vertebral bones. During PLIF surgery, the disc material is removed through an incision in the back. The cages are filled with bone graft material and inserted in the space where the disc material was taken out.
It’s hard to say if one fusion method is best for everyone. Each patient has his or her own unique problems and needs. Different patients have different amounts of spinal damage and instability. The surgeon tries to restore the patient’s normal spinal angles and curves.
Is extra support needed along the front of the spine? The cages used in PLIF can also be put in from the front of the spine to support the front column of the spine. In this study, researchers use a special tool to measure how much force it takes to spread apart (or distract) the bones at the fused site. This force is called distraction stiffness. It is a measure of spinal stability. The researchers compared the amount of distraction stiffness with findings on X-rays. Since doctors can’t measure distraction stiffness before surgery, the hope is that X-rays show the same information in a different way. The X-rays show disc angle, spinal range of motion, and disc height.
The authors report that disc angle in flexion and range of motion as seen on X-ray can be used to help decide if a patient needs anterior column support. The researchers report which patients could benefit the most from this type of fusion. The authors say the information from this study will help in deciding if anterior column support is needed in lumbar fusion.