Five-Year Study: Comparing Lumbar Artificial Disc Replacement to Spinal Fusion in Patients with Degenerative Disc Disease
- An analysis of previous clinical trials found that total disc replacement (TDR) is “as good as or better than” spinal fusion for treating lumbar degenerative disc disease (DDD).
- People who underwent TDR experienced greater improvements in their functioning and were more satisfied with the procedure. They were also less likely to require additional surgery within five years, compared to people who had spinal fusion.
- The authors of the new study wrote that TDR may decrease degeneration in adjacent discs, which could reduce the need for additional surgery later on.
- Other research mentioned by the authors shows that TDR has shorter operating times and hospital stays compared to spinal fusion surgery.
The two surgical options for treating lumbar degenerative disc disease are spinal fusion and artificial disc replacement (ADR).
Several studies suggest that ADR offers greater benefits for patients with lumbar DDD, including reducing disability and back pain, and offering a safer procedure with fewer complications.
To provide a clearer picture of which surgical method is more effective and safer, a group of researchers combined and analyzed data from several previous studies that compared spinal fusion to ADR.
Here’s what you need to know about the new study.
Some research has found that between 62 and 84 percent of people will experience low back pain at some point in their life.
A common cause of this type of pain is lumbar degenerative disc disease. This is an ongoing (chronic) degenerative condition that affects two parts of the lower spine — the vertebral bodies and intervertebral discs.
Treatment for lumbar DDD usually begins with nonsurgical approaches, such as medication and physical therapy. If a person’s pain doesn’t improve after several months, surgery may be needed.
Currently, there are two surgical options.
The first is spinal fusion, in which two or more vertebrae in the patient's spine are permanently fused. This method reduces excess motion in the spine that causes chronic back pain.
Over the past few decades, the fusion rates and effectiveness of this type of surgery have improved. However, the authors of the new study report that as many as one-third of patients continue to experience pain after spinal fusion, which may result in another surgery.
The newer surgical option is artificial disc replacement (ADR), in which a damaged disk in the spine is replaced with an artificial disc.
One type is known as total disc replacement (TDR). This involves replacing all or most of the disc tissue with an implant.
In a study published 2018 in the Global Spine Journal, researchers reviewed four previous clinical trials that compared total disc replacement to spinal fusion as a treatment for lumbar degenerative disc disease.
The trials included people with chronic lower back pain due to lumbar DDD affecting one vertebrae. All of the people had tried nonsurgical approaches first, but their symptoms had not improved.
Researchers followed people for 5 years after surgery and measured the following outcomes:
- The Oswestry Disability Index (ODI): a questionnaire used to measure a patient’s permanent functional disability.
- Back pain scores.
- Re-operation: whether further surgical treatment is needed due to a device-related failure.
- Patient satisfaction or willingness to choose the same surgery again.
- Serious adverse events related to the device, including injuries and death.
Using statistical methods, the authors combined the data from the studies, in what’s known as a meta-analysis. This allowed them to make stronger conclusions about how TDR stacks up to spinal fusion over the long-term.
Based on the four studies, the authors found that total disc replacement offered several clinical advantages over spinal fusion after 5 years. Here is a summary of the results:
- Oswestry Disability Index (ODI): People who underwent TDR were more likely to have a clinically relevant improvement in their ODI score compared to those who had spinal fusion surgery.
- Back pain scores: Back pain scores improved about the same for TDR and spinal fusion.
- Reoperation: People who underwent TDR for lumbar DDD were 48 percent less likely to need further surgery after 5 years, compared to those who had spinal fusion.
- Patient satisfaction: People who had TDR surgery were more likely to be satisfied with the procedure after 5 years, compared to those who underwent spinal fusion.
- Serious adverse events: The studies reported these in different ways, so the authors couldn’t combine the data. However, the authors wrote that all of the studies found that TDR had better safety outcomes compared to spinal fusion.
In roughly 62 to 84 percent of DDD patients, low back pain becomes chronic
The purpose of artificial disc replacement surgery is to stabilize the patient's spine while preserving the patient's natural movement of range and motion. The artificial disc used for artificial disc replacement (ADR) allows the patient to move freely without pain or strain while supporting the spine's natural range of motion with increased flexibility.
The authors included only studies with high-quality designs. These were all randomized controlled trials, meaning the surgeons who implanted the devices did not know if a patient would be undergoing spinal fusion or TDR until the time of surgery.
The studies followed patients for five years, which provides a better idea of the long-term outcomes. There was also little variation among the studies, which means they provided similar results.
The meta-analysis could not address every factor that might affect the outcomes, such as which technique the surgeon used or how patients were cared for after surgery. However, the authors wrote that the original studies were done at large medical centers, so these variations were most likely taken into account.
Based on the study's evidence, the authors concluded that total disc replacement is an “effective treatment” for lumbar degenerative disc disease, compared to spinal fusion.
TDR also offers “several clinical advantages that can benefit the patient,” such as greater improvement in disability (ODI) scores, higher patient satisfaction, lower risk of needing a re-operation and fewer safety problems.