When fusing bones of the spine together, surgeons can use hooks, wires, screws, rods, or plates. Recently special screws with superior strength called transpedicular screws have been in use. The location of the fusion has a large bearing in deciding which type of fixation to use.
In this study, translaminar screws were used to help fuse the upper thoracic spine (T1 or T2). This is a tricky area of the spine to fuse because the shape of the bones is changing from the cervical spine to the thoracic spine.
The shape, width, and size of the thoracic vertebrae all must be considered during fusion. The changes in anatomy at this spinal level make using transpedicular screws more of a problem. For example, the epidural space between the spinal cord and the vertebral bone is small. A screw long enough to help hold the spine in place could go right through this space.
Translaminar screws avoid this problem. From the way they are placed in the spine, there’s less risk of damage to the nearby nerves. Surgeons find the use of translaminar screws easier than transpedicular screws. They can see to thread the screw through the bone better than with the transpedicular screws.
Using MRIs, X-rays, and CT scans, seven patients having translaminar screw fixation were followed for at least one year. At the end of that time, none of the 19 screws placed in seven patients had broken or pulled out.
The authors conclude translaminar screws work well in patients with good bone and good alignment in the upper thoracic spine. Using transpedicular screws in this anatomically challenging area can be a problem. This group of patients will be followed much longer to see how long spinal stability lasts.