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Results of FDA Pilot Study Comparing Single-Level and Multiple-Level Disc Replacements

Disc replacements are now available for the low back (lumbar spine) and the neck (cervical spine). The patient most likely to qualify for this surgery is someone with a herniated disc putting pressure on the spinal cord. Only one level is replaced. This is due to concerns that other levels will start to break down.

This is the first study published comparing the results of single-level cervical disc replacement with multiple (two or three) level replacements. Pain levels, function, and motion were used as measures of the results. X-rays and MRIs were also used to show the position of the implant. The same studies also showed the biomechanical motion in each spine.

The same surgeon treated everyone. An FDA-approved porous coated motion (PCM) implant was used. This type of implant allows bone to grow in and around the surface. Patients in the single-level group were very similar to patients in the multiple-level group. They were the same age and sex. They had the same severity of condition.

Patients were followed for up to three years. The results showed greater overall improvement for the multilevel group. Although the multilevel group had a longer hospital stay, their neck disability improved more. The reoperation rate and the number of problems after the operation were the same between the two groups.

The authors comment that this study shows that either operation does not burn any bridges. Anyone needing further surgery only required a minor operation. No one had to have the implant removed and a spinal fusion done.

Further study is needed before multiple disc replacements can be used for everyone. In fact, insurance companies won't pay for improved technology. They want some proof that the results are superior not just not inferior. Two to five-year results are needed before a change can occur in the standard single-level only policy.

References: Liuz Pimenta MD, et al. Superiority of Multilevel Cervical Arthroplasty Outcomes Versus Single-Level Outcomes. In Spine. May 20, 2007. Vol. 32. No. 12. Pp. 1337-1344.

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