rbaz123MemberApril 6, 2012 at 6:14 pmPost count: 1
Dr. Corenman , after 5 months of painless but unusual needles and pins feeling in both hands followed by uncoordinated stiffness in the legs making running impossible and walking difficult at times concluded me to take measures to see the right Dr. through EMG test than MRI I was diagnosed with a compress spinal cord between C5 & C6 and have the classic signs of Mylopothy. I understand that surgery at this point is my best and only option to recover …. The fusion plate which was recommended is a new V shape that fits flush between the vertabra’s eliminating the 2mm thickness of the traditional plate that is screwed from the outer perimeter. ….. The question I have is do they currently make any Bioresorbable plates that will desolve naturally with time leaving the fused vertabra on its own with no titanium parts left inside your body ?
Thank you ….. Robert 47 yrs oldDonald Corenman, MD, DCModeratorApril 6, 2012 at 8:23 pmPost count: 8459
I am not sure how the myelopathy you express was diagnosed. An MRI or CT myelogram along with a meticulous physical examination is critical to diagnosing this condition. An EMG is not a test that will reliably reveal myelopathy. Let us then just assume that you have myelopathy from cord compression at C5-6.
You are most likely discussing one of the disc spacers that fits within the disc space and has its own screw fixation into the endplate of the vertebra. By your discussion, the one proposed by your surgeon is made of titanium and you want to know of bioresorbable materials.
I have a number of comments. First is that any disc space “device” has to be biologically active. That is, the surface area of the disc space in the cervical spine is relatively small and any inert spacer will make the potential surface area for fusion that much smaller. You are depending upon joining the spacer to the bone of the vertebral body and these inert spacers reduce the biologically active surface area.
That means to me that “spacers” made of plastic (PEEK) or of metal (titanium) reduce the success rate of fusion and increase the time to solid fusion. The secondary problem with metal spacers is that metal is a radioopaque material and X-ray cannot penetrate it. Using X-ray to determine fusion status is thwarted.
The graft material made of iliac crest bone (autograft or allograft) fits my bill as a biologically active material that has wonderful healing properties. The only problem with this material is that you have to take the time to carefully mill the surfaces of the receiving vertebral endplates to get a proper bed for fusion. That takes time.
The two mm thick plate you mention that is fitted on the front of the vertebral body is not as relatively thick as you think. There are two reasons for that. First is that the anterior longitudinal ligament is one mm thick. This ligament is removed from the vertebral bodies undergoing surgery to fit the plate. The second is that any bone spur that protrudes from the front of the involved vertebral bodies (and these spurs can be up to eight mm thick) is milled down to the original width of the endplate.
So even if there is no anterior spur to mill down (rare), the plate only adds one mm of thickness. If there is spur present, the addition of the plate will still reduce the total anterior protrusion substantially.
Bioresorbable plates have been tried with poor success. You have to remember that any material resorbed goes through a process of inflammation to resorb. This inflammation is generally detrimental to the bone.
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