Multiple-level disc replacement is artificial disc replacement surgery performed at two, three, or four levels of the spine. Because the spine is essentially a column of spinal bones with spinal discs in between, each spinal disc is a “level” of the spine. For example, a multi-level artificial lumbar disc replacement may be performed at the L2-L3 level, the L3-L4 level, L4-L5 level, and the L5-S1 level during a single surgery.
Sadly, degenerative disc disease tends to affect more than one spinal level at a time. So, if a patient requires artificial disc replacement at two or more levels, multi-level disc replacement may be necessary. The indications for multiple disc replacement are nearly the same as for a single-level replacement: The patient, in general, and the spinal bones, in particular, should be in good health. That means the patient cannot have active cancer, osteoporosis, or any of several other disqualifying illnesses. That said, most patients with symptoms of degenerative disc disease, disc herniation, or bone spurs at more than one level are candidates for multi-level disc replacement.
Multi-level lumbar disc replacement is artificial lumbar disc replacement surgery at two or more levels at L1-L2, L2-L3, L3-L4, L4-L5, L5-S1. In a clinical study, 159 patients who received adjacent 2-level (n=114), 3-level (n=41), or 4-level (n=4) lumbar total disc replacement had significantly less pain and disability and did not need revision surgery or second spine surgery in the same area for at least six years.
2-level lumbar disc replacement is the most commonly performed multiple lumbar disc replacement surgery. Diseased discs are removed from the spaces between vertebrae in the lower back and replaced with two artificial discs.
3-level lumbar disc replacement is performed less often than 2-level lumbar disc replacement but can be performed on three adjacent lumbar discs by experienced surgeons.
4-level lumbar disc replacement is not common and should only be performed by spine surgeons who have experience with this procedure. That said, patient who have 4-level lumbar disc replacement do well.
Outcomes after multi-level artificial cervical disc replacement surgery are also quite good. In a clinical study of 139 patients, 116 who had 3-level disc replacement surgery and 23 who had 4 level cervical disc replacement, the procedure was safe and effective for seven years (the end of the study). Most patients reported less pain and disability after multi-level artificial cervical disc replacement and were satisfied with their results.
2-level cervical disc replacement (surgery at 2 adjacent levels) is the most commonly performed multi-level disc replacement procedure; outcomes are quite good even a decade later.
Cervical disc replacement at three adjacent levels is less commonly performed than 2-level cervical disc replacement, but in skilled hands, the procedure provides long term pain relief with limited need for revision surgery.
4-level cervical disc replacement is the least commonly performed cervical disc replacement procedure, but still provides good outcomes when performed by a spine surgeon with experience in this procedure. As you may imagine, spinal mobility tends to be substantially better after 4-level cervical disc replacement than 4-level cervical disc fusion.
In a multi-level artificial disc replacement surgery procedure, the patient is placed under general anesthesia. The spine surgeon makes an incision in the side of the neck for cervical disc replacement or the abdomen for lumbar disc replacement. The spinal bones are gently exposed, and the diseased disc is removed at one level. Once the space is free of disc tissue, an artificial disc is placed in the newly vacant spot. This sequence of disc removal and artificial disc placement is repeated two or three more times, depending on the number of spinal levels that need to be treated. The area is closed with sutures (stitches), and the patient is moved to the post-anesthesia recovery unit.
The main alternatives to multiple-level disc replacement are hybrid disc surgery or multiple-level fusion. In hybrid disc surgery, at least one level is treated with spinal fusion, and at least one level is treated with artificial disc replacement. Each time a spinal level is fused, the two fused bones will never move separately from each other. Consequently, the spine is less mobile at that location. The more bones (levels) that are fused, the less mobile the spine will be. While artificial disc replacement and spinal fusion both relieve pain and related symptoms, each time a level can be replaced with an artificial disc rather than fused, the spine has a much better chance of remaining mobile. Also, the recovery time after artificial disc replacement tends to be shorter than it is for fusion.
The risks of multiple-level disc replacement are similar to the risks of single disc replacement. As with any surgery, there are risks of excessive bleeding, excessive pain, infection, negative reaction to anesthesia, or a blood clot in the legs. The risks of multiple-level disc replacement include implant migration, implant malplacement, narrowing of the spinal canal, nerve damage, implant wear or failure, pain, or symptoms do not fully resolve. The rate of any of these complications increases with the number of levels treated; however, the procedure is generally well tolerated overall.
Healthier patients are more likely to have more success with multiple-level disc replacement surgery, so the best way to prepare is to get as healthy as possible. People who smoke are at relatively high risk of complications from surgery. Therefore, patients who can manage to stop smoking will have better outcomes. People who are physically fit also do better with multi-level disc replacement. While most exercise may be limited by neck or lower back pain, ask your surgeon or physical therapist to recommend exercises that can be done with little or no additional discomfort. Lastly, some medications should be continued during surgery, and some medications need to be stopped. Patients should make sure they understand whether and how to take their medications up to two weeks before and after surgery, and on the day of the procedure.
Recovery from multi-level disc replacement is slightly longer than it is for single level disc replacement but tends to be shorter than for fusion—especially when compared to multi-level fusion. In 2-level cervical disc replacement, for example, patients returned to work about 30% faster than those who had 2-level cervical disc fusion.