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My interval of ordering X-rays depends upon the type of fusion graft requested by the patient. I offer the patient their own bone (autograft) or donor bone (allograft). I always use iliac crest bone graft as it has the best structural integrity with the greatest surface area of biological activity.

I sometimes post-operatively follow patients that have had surgery elsewhere. There are surgeons that use PEEK cages (plastic) as spacers and some that use fibular allograft so I will delineate the algorithm for all of these.

For autograft iliac crest patients, I obtain X-rays at six weeks and three months post-operatively. Almost all are healed by six weeks and three months confirms the healing. If there is a radiolucent line that still is apparent at three months, an X-ray at six months is required.

For allograft iliac crest where I have performed the operation, again X-rays at six weeks, three month and then six months to confirm fusion (there is a higher non-fusion rate with allograft that needs to be followed).

For PEEK cages and fibular allograft, I follow these cases out for at least one year with X-rays. Unfortunately, since the PEEK cage is biologically inactive, there will always be a “line” at the interface between the vertebral body bone and the cage. The fusion occurs inside the cage and is difficult to visualize without a CT scan. What I look for is evidence of non-fusion such as haloing of the cage against the bone, loosening/fracture of the screws or motion of the segment on flexion-extension x-ray. This is also the algorithm I use for fibular allograft as this thick cortical structure does not incorporate well into native bone. I have seen radiolucent lines three years out from the use of this graft material in spite of a solid fusion.

Even with non-fusion, there is a small chance that with time, the fusion might “take”. If the graft fractures/collapses or the graft recesses into the vertebral body as the PEEK cages are prone to do, there might come a point that with settling the construct becomes stable and fusion might occur. This is why there are some fixation plates on the market that have a sliding channel for the fixation screws to compensate for this collapse.

If the level has obvious fracture, graft collapse or erosion, the hardware is loose and there is motion on flexion/extension X-rays, a CT scan is used to confirm the pseudoarthrosis (non-fusion). If the level is painful or unstable, revision surgery is called for. This might take the form of a posterior fusion or a revision anterior fusion.

Dr. Corenman

You report pain in the cervical spine centrally. The lumbar spine pain most likely is from another source. The upper extremity symptoms seem to be variable. First, which symptoms are worse, the neck or the arms? If the neck, what is the percentage of neck vs. arms? 70/30, 80/20 or? What makes the neck pain worse? Does time of day make a difference? What is the intensity of the pain on a 0-10 scale?

The X-rays can be revealing. You note significant degeneration of C4-7 and straightening of the normal lordosis curve. Straightening of the curve is typical with degenerative change of the discs. The discs are trapezoidal in shape and wear of these discs will straighten the spine.

I will assume that you have already had substantial treatment in the form of physical therapy, chiropractic and other forms like acupuncture and medications. You report that injections have failed to give you relief.

If you have failed everything and the symptoms are disabling, you might be a candidate for a work-up for surgery. First, facet injections might be in order. The cervical facets can generate central neck pain. Temporary relief of your pain with injection of the facets may make you a candidate for ablation of the nerves that send signals from the facets (rhizolysis).

If that procedure gives you no relief, then you might be a candidate for fusion surgery. First, the range of motion of the C4-7 levels on flexion- extension films has to be very limited or there has to be instability present. Some surgeons would then use a test called a discogram to test discs above. This test would have to be negative (no pain generated from the discs above). You would then need a long talk with your surgeon regarding surgery, the expectations, the potential results- both good and bad.

Dr. Corenman

Unfortunately, your information regarding the radiation from DMX machine is wrong. Each picture from the machine is about the same amount of radiation from one standard image. Based upon your statistics, you have had 2700 images of your neck at one sitting.

X-rays are not static if performed at the endpoints of motion. For example, the lateral flexion and extension X-rays of the neck will show the endpoints of motion of each vertebra with the respective position. If you compare these endpoints of motion with the neutral lateral film, you gain the knowledge of pathological motion.

DMX in my opinion will substantially over-diagnose many problems that are really normal variants. I assume that the surgeons you have seen also know this and in general, no one wants to perform surgery simply on the findings of the DMX.

Dr. Corenman