The most widespread surgery when solving spinal problems is fusion, which involves removing the movement of 2 vertebrae by placing bars, screws and bone graft. Although it is the reference technique, it is paradoxical that to solve the back problems it is best to remove the movement. As an alternative, there are disc prostheses whose philosophy is to maintain the movement of the spine.
What is a lumbar disc prosthesis?
A disc prosthesis is a system designed to replace an intervertebral disc and that attempts to perform the same functions as the disc it replaces.
All prostheses consist of two parts, one that serves as an anchor for the prosthesis to the bone of the vertebrae and another in which the movement of the prosthesis is performed. Depending on the part where the movement is performed, there are 2 types of disc prostheses.
Prostheses that simulate the behaviour of the disc
These prostheses try to imitate how the intervertebral disc behaves. Usually, they are composed of the rigid part that joins the vertebra and a viscoelastic material located in the middle that has similar behaviour to the disc in terms of deformability, load transmission, elasticity, etc.
Prostheses that try to reproduce the movement of the disc
They are the most commonly used prostheses, they also consist of 2 parts, one to anchor the prosthesis to the bone and a mechanical system that allows movement. These prostheses, in turn, can be divided into constrained or unconstrained depending on whether or not the rotational movements are limited.
Access to the intervertebral disc to place a prosthesis is done through the anterior part. For this, an incision is made in the abdomen. The first thing we do is separate the abdominal muscles. Once separated we will see the peritoneum, which is a bag in which the intestines are located. We do not need to open the peritoneum, we simply move it to the side. When we have the separate peritoneum, we find direct access to the disk. In that region, we are careful with the aorta, the iliac arteries and the vegetative nerves. The L5-S1 disc is usually found in the bifurcation of the iliac arteries, however, the L4-L5 disc may be covered by the aorta or the iliac artery and must be carefully separated to access the disc.
Once we have access to the disc we remove it and put the prosthesis according to the particular technique for each type of prosthesis.
The approach to put a prosthesis disc is very anatomical and really is not very aggressive which brings advantages at the time of recovery.
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