360 Motion Preservation Surgery

360 motion preservation is not a single spinal device and/or procedure, but a concept, which includes many types of spinal devices and procedures. The name and concept is adapted from 360 fusion. The major difference between the two is that 360 motion preservation preserves the motion of the spine and 360 fusion leaves the patient in a permanently fixed position in the segments, where it is used.

Both concepts address severe conditions of the spine, such as degenerative scoliosis, where dorsal and ventral procedures are needed. The ventral procedures address the anterior vertebral column of the spine (the stack of vertebral bodies and discs) and the dorsal procedures address the posterior laminae column of the spine (the chain of laminae, which includes the facet joints).

Like a flat tire, which makes the steering and support of a car unstable, so does a flat (desiccated or herniated) disc make the spine vertically unstable. Therefore, an Artificial Disc Replacement (ADR), which will reestablish the height of the intervertebral disc space and add stability to the spine, is part of 360 motion preservation.

To extend our automobile analogy further the facet joints, like the tire rods of a car, guide and limit the movement of each spinal segment (the tires). It can be more directly said that the horizontal stability of the spine is the main responsibility of the facet joints. The facet joints limit the rotation of each spine level. When the spinal bony processes, which make up the facet joints, are missing because of a procedure like a laminectomy or facectomy, or malfunctioning from disease, 360 motion preservation utilizes dorsal pedicle screws as anchoring points for posterior fixation, just like some fusions. These screws are featured prominently to the right. However, unlike fusion, the DSS connectors in motion preservation are spring-like allowing for movement. The spring-like connectors help return the spine segment to a neutral position. The nature of these connectors can vary, so the correct application and sizing of the connectors is critical to a good outcome.

Degenerative scoliosis can present not only with a coronal C curve in the spine, but also with rotation of the spine. The C curve is obvious in the second picture (MRI) on this page and to a lesser extent in the image (X-ray) to the right of this paragraph. However, rotation is indicated in the X-ray on the right and the first panel in the image on the page, where we can see the spinal process to the left of the entire vertebral body in the first image and we can see it to the left of the midline in relation to the vertebral body in the second image. In these cases, particularly if a spondylolisthesis is present, hybrid constructs are frequently used, i. e. the use of 360 fusion and 360 motion preservation in combination and adjacent to each other. The ability to connect fusion segments with the motion segments, greatly enhances the ability of the surgeon to preserve a majority of the motion of the spine, while straightening it. This is a rather unique property of DSS, which is an invention of Prof. Dr. Bertagnoli. Again we must say that the correct selection of the screws and connectors must be made by the surgeon. This is very much an engineering task.

Modern back surgery requires much more engineering than traditional back surgery. And the surgeon must look at each case’s individual characteristics more so than previously done in medicine.