Performance of Plate-Only Laminoplasty

» Performance of Plate-Only Laminoplasty
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Surgery to take pressure off the spinal cord in the neck area continues to progress and change. New and better surgical techniques have the potential to improve results for patients suffering from pressure on the spinal cord.

In this study, surgeons from Emory Spine Center in Atlanta, Georgia use a special plate as the only fixation device after performing a laminoplasty for cervical myelopathy. Cervical refers to the neck and myelopathy means damage to the spinal cord. This condition can cause disabling neck and arm pain. Laminoplasty is a surgical way to cut the bone from around the spinal cord to take the pressure off.

But without the bone to support the spine, instability can result. So surgeons have found various ways over the years to give the spinal cord some added room while stabilizing the vertebrae (spinal bones). For one thing, they found they could cut through the lamina (pillar of bone that forms an arch around the spinal cord) and make a hinge to move the bone away from the spinal cord without removing the bone.

Then using spacers made of bone or ceramic, the hinge-door could be propped open. This step keeps the hinge-door from collapsing or closing back on the spinal cord. Over time, they found that the spacers could pop out or fall into the spinal canal. And the technique of using the spacers required advanced surgical skills much like a master carpenter.

The use of metal plates to hold the lamina hinge-door in place is the newest development. Plating can be done with or without the bone spacers called struts. The 54 patients in this study with cervical myelopathy had a laminoplasty with plate-only fixation.

Two advantages of a plate-only approach are the cost savings (it's much more expensive to add bone struts) and the shorter time under anesthesia required for a plate-only procedure. A shorter operative time also saves money but even more importantly, reduces the risk of complications for the patient.

CT scans were taken at three, six, and 12 months after surgery to see how the healing was progressing. CT scans take pictures in series a slice at a time horizontally across the spine. The CT-slices give a visual representation of what's going on at each level of bone. It's possible to see bone bridges being formed, bone remodeling, and bone healing.

The results were very good. There were no cases where the plates broke, shifted, or failed in any way. A couple patients had a screw back out but it didn't cause any problems. Healing was complete after three months in more than half the patients (55 per cent).

Three-fourths of the patients had complete healing at the end of nine months. And by the end of the first year, 93 per cent were healed. The remaining seven per cent were considered "nonunions". The area filled in with fibrous scar tissue rather than bone but the spine was still stable.

Even though there were only 54 patients in the study, the total number of laminoplasty procedures with plating was 217 because many patients had more than one level done. The longest laminoplasty was done from C3 down to T1. Most of the patients had a laminoplasty from C3 to C7. No one had any further neurologic problems from the surgeries.

In a side note, the surgeons saw that a laminoplasty with plating healed the fastest when done at the C6-7 level. One reason given for this outcome is that the bone where the hinge is made tends to be thicker at this level than anywhere else. More bone stimulated and releasing growth factors creates faster healing.

The CT scans showed the expansion around the spinal cord formed by making a hinged-door and propping it open with the plate was a complete success. Since only plates were used without additional bone grafting, the results of this study also show that adding bone graft isn't really necessary. And that's good news because sometimes patients have more problems at the graft site than at the surgical site. Of course, there's a cost savings there as well.

In summary, this is one of the first studies to report on the use of plating only when performing laminoplasty for cervical myelopathy. The high success and low complication rates without the use of supplemental bone grafting suggests this technique to expand the spinal canal may become a standard procedure in the future. Patients have immediate spinal stabilization and can move after surgery right away. The cost savings is an added feature to consider.

Reference: John M. Rhee, MD, et al. Plate-Only Open Door Laminoplasty Maintains Stable Spinal Canal Expansion with High Rates of Hinge Union and No Plate Failures. In Spine. January 2011. Vol. 36. No. 1. Pp. 9-14.

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