Hybrid Lumbar Disc Surgery
When is hybrid lumbar surgery appropriate and what are the challenges?
A hybrid surgery is when a fusion is done at one level and an artificial disc is done at another level during the same surgery. There are many ways to combine fusions and artificial discs. The biggest problem however is getting the insurance companies to pay for this combination.
Years ago it was easier to get a a single level fusion and single level artificial disc replacement approved by insurance, but that has recently changed. Insurance companies have continued to ratchet down their approvals for such hybrid surgery. So, while it seems like it would be the best option for you as a patient, the insurance company does not always agree.
There are definite times when we would want to do a hybrid procedure with a fusion at one level and an artificial disc at another level. For example, a condition called spondylolisthesis is one of the most common problems in which there is slippage of one vertebral body on the other. This is an unstable condition that cannot be treated with an artificial disc. If the adjacent or next level is also degenerative and not unstable then it would be a candidate for disc replacement if the patient has the appropriate indications. This combination of fusion and arthroplasty is an example of a hybrid surgery.
A scenario when arthroplasty would not be appropriate is if you already had multiple surgeries at one level that compromised the facet joints, which are the little connecting joints in the back part of the spine, causing that disc segment to be unstable. To date we do not have any arthroplasty implants that are stable enough to use for these situations of spinal instability. However, if multiple stable levels are involved then a hybrid surgery would be appropriate.
In many cases it would be appropriate to do a two level disc replacement surgery. There are some surgeons who believed that there is not enough motion at the bottom level of the spine, called L5/S1, to consider doing a disc replacement. However, if we look at the FDA trials, the L5/S1 level was the most common level treated. If done appropriately one can restore and maintain motion at that level.
Nonetheless in our Texas Back Institute internal series we found that there is little difference in outcomes between a two level disc replacement surgery at L4/5 and L5/S1 and a hybrid surgery where a fusion was carried out at the L5/S1 level and artificial disc at the L4/5 level. In a perfect world in which insurance was not an issue and the patient had the appropriate indications for such surgery, a two level disc replacement would be ideal. Fortunately, the Prodisc L implant has recently been FDA approved for two level use as of April 2020 even though the study was carried out and completed around 2007. Some insurance companies are indeed approving a two level
disc replacement procedure and even some are approving a hybrid procedure.
What happens if your surgeon suggests a hybrid procedure but your insurance will not pay for it? You should then discuss your options with your surgeon. Obviously, insurance companies are more than likely to pay for a two level fusion, but that would not be the best option for you depending on your age and your activity level. In this case, there are ways to still obtain the hybrid surgery but may require out-of- pocket expenses on your part. Again, this should be discussed with your surgeon as to what the alternatives would be.
Hybrid Cervical Disc Surgery
It is not unusual for a patient to have more than one level of disc in the neck (cervical spine) wear out. In the instance where multiple levels need to be included in the surgical plan, the traditional surgical approach is to fuse each level. Taking away the motion at two or more consecutive levels
with a multilevel fusion can reduce the overall neck range of motion and is expected to put extra stress on the remaining non-fused disc levels. Cervical disc replacement (arthroplasty) is an attractive option to preserve motion; however this may not be suitable for patients with symptomatic multilevel cervical disc degeneration given its relatively narrow indication to be performed at 1 or 2 levels.
What can we do in this situation? A hybrid surgery is a combination of fusion and arthroplasty. In this surgical plan, the most collapsed, stiff level is fused and the level with motion is replaced. Often times the lowest level or levels are treated with a fusion and the upper level is treated with an arthroplasty.
This combination of ACDF (fusion) and ACDR (replacement) has been increasingly utilized over fusion alone for patients with symptomatic multilevel disc degeneration. Hybrid surgery aims to preserve as much segmental motion as possible, while minimizing stress to the surrounding levels.
Challenges do exist with coverage for hybrid surgery by some insurance companies, which may limit access to this option for some patients or increase the out-of-pocket costs to others. It is important to understand what the surgical options through a detailed conversation with your surgeon. Through further research proving the benefits of cervical hybrid surgery, we are hopeful that access to this combination option becomes accessible to all patients.
by Dr. Richard D. Guyer, MD and Dr. Ehsan Jazini, MD
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