Can I get my spine joint replaced like my knee joint?!!!
If you go to a knee surgeon due to pain from severe degeneration or arthritis of the knee, the doctor doesn’t advise you knee fusion surgery. He usually does a knee replacement surgery instead and will relieve you of the pain and you still can move your knee. Pain is relieved and function is restored. But why does the spine surgeon advise a fusion surgery instead of replacement ?!!
Well…. the spine motion segments including the disc and facet joints are much more complex than a knee or hip joint and is difficult to reproduce the same results that apply to these joints .Also there are multiple joints stacked on each other increasing its complexity!!
Hence the best available option was fusion surgery in spine. Spinal fusion is a surgical procedure designed to combine two or more vertebrae together, eventually forming a fused bone. This technique is used to immobilize the vertebrae in order to eliminate, or significantly reduce, the pain caused by abnormal movement of the vertebrae through immobilization.
What is motion preservation surgery in spine ?
It is a spine surgical technique to maintain normal or near normal motion of the spine with pathology to prevent adverse outcomes commonly seen with conventional spinal fusion, most notably the development of adjacent-level degenerative disc disease.
One of the key factor in spinal motion and stability is the intervertebral disc and also the joints of the spine termed as facet joints. Replacing these was a challenge in the past.
But due to advancement of techniques and better innovation and implants the scenario is changing. These days motion preservation is possible in selected cases and the indications to do a motion preservation is growing as surgeons and innovators are pushing boundaries.
Let’s analyse the various motion preservation methods available :
2 main categories: artificial discs and dynamic stabilization devices.
Artificial disc replacement (ADR)is available for cervical and lumbar spine.
The indications for ADR in lumbar spine and cervical spine varies. The most significant variation is that lumbar spine disc replacement is done for discogenic back pain and leg pain whereas cervical Dis replacement is done for nerve compression symptoms rather than neck pain in a broad sense.
Here Iwill be discussing mainly on the cervical disc replacement
Cervical spine ADR.
Duplicating the natural disc’s form and function with an artificial disc is challenging. However, several artificial cervical discs have been developed and are available as a surgical option to treat cervical disc problems
Aims for disc replacement.
1.Relieve neural compression :
When a disc herniates or begins to degenerate and collapse, there is less room for the nerve roots (and sometimes the spinal cord) to function, which can be a source of chronic pain, tingling, numbness, and/or weakness radiating from the neck into the arm. Clearing away the damaged disc and inserting an artificial disc aims to relieve pressure on any compressed nerves to give them space to heal and function normally. If the spinal cord was previously compressed, relieving pressure on it may help resolve or prevent progression of other symptoms, such as trouble with coordination, walking, and/or bladder or bowel control.
2.Maintain motion at the repaired spinal level.
By replacing the damaged disc with an artificial disc, natural biomechanics can be more closely retained throughout the cervical spine when the neck moves. While both ACDF and cervical ADR aim to remove a problematic disc and restore normal disc height, they differ in that ACDF fuses the adjacent vertebrae so motion is lost at that spinal level. The chance of the next level of the spine having to take the extra load is reduced in replacement surgery
3: Reduced Need for Revision Surgery
The main criticism of spinal fusion is that there is substantial evidence that revision surgery is often needed. Studies have shown that after a level is fused, the likelihood of adjacent levels developing degenerative disc disease (DDD) increases substantially. Motion preservation procedures do not carry this concern.
Also, not every patient suffering from degenerative disc disease requires a fusion. Motion preservation devices can delay or prevent spinal fusions from becoming necessary.
4: Quicker Recovery Time
The invasive nature and longer recovery time of spinal fusion procedures is a major deterrent for patients, particular those belonging to the older generation. In 2017, the fastest-growing age demographic in the U.S. was 65 and older. Many of these patients choose to forego spinal fusion and focus instead on pain management, or options like motion preservation that offer quicker recovery rates.
Quicker recovery is also an incentive for the healthcare system, as it reduces the burden placed on the hospitals, facilities and staff involved in the procedure. This overall reduction of strain means that everyone involved is pushing for this transition.
Who is a candidate for cervical disc replacement ?
Confirmed cervical disc disease
An MRI can show soft tissues—such as discs, nerve roots, and the spinal cord—in addition to bones. If imaging shows degeneration of one or more discs, the next step is to determine if any of the degenerating discs correlate to the pain or other symptoms experienced by the patient. If MRI findings correlate then the patient could be considered for a disc replacement.
Radicular pain and/or neurological deficits caused by a problematic disc.
Most commonly, an inflamed cervical nerve root corresponds to problems with pain, tingling, numbness, and/or weakness that radiate down into the arm and/or hand. If the spinal cord is compressed within the cervical spine, cervical myelopathic symptoms and/or myelopathy may be experienced anywhere below the level of compression, such as pain that goes into both hands and/or legs, hand weakness/numbness, leg weakness/numbness, trouble with coordination or walking, or difficulty with bladder/bowel control.
Nonsurgical treatments have been tried and failed
Cervical degenerative disc disease symptoms typically can be managed with nonsurgical treatments, such as rest, ice, heat, medications, physical therapy, and/or therapeutic injections. If the symptoms persist at least 4 to 6 weeks despite nonsurgical treatments, a surgical solution is more likely to be needed for pain relief.
Age is not an absolute contraindication, however younger patients in general fulfil the criteria for motion preservation as advanced age causes weak bones and degeneration.
Contraindications for Cervical ADR
Cervical ADR is not recommended for patients with any of the following:
Advanced spinal degeneration.
Replacing a damaged disc cannot help improve problems associated with an ossified posterior longitudinal ligament or degenerating facet joints, such as from osteoarthritis or ankylosing spondylitis.
Also, while artificial cervical discs have been approved for use at 2 adjacent spinal levels by the FDA in some cases, they have not been approved for use in 3 adjacent spinal levels.
Weakened bones.
If the bones are weak, such as from osteoporosis or a bone infection, the artificial disc is less likely to stay in place after the surgery.
Prior cervical spine surgery.
An underlying instability from a previous neck surgery may reduce the chances for cervical ADR to be successful.
Other contraindications include
- Vertebrate Body Fracture
- Inflammation and Infections
- Injuries of Spinal ligaments
- Severe Spinal stenosis
- Tumours of the spine
Efficacy of Cervical Artificial Disc Replacement Surgery
While cervical artificial disc replacement surgery is still considered a newer procedure, the data collected thus far have shown it to be relatively safe and effective for reducing neck and arm pain resulting from a compressed nerve root or spinal cord.
Several randomized controlled trial studies, ranging from 2 to 10 years, have shown clinical success rates for cervical ADR to be similar or even better than ACDF clinical success rates. However, there is currently a lack of data on the success or failure of cervical ADR in the long run, such as over 15 or 20 years, which presents its own unknown risk and must be taken into consideration when deciding on the surgery.
Current studies do demonstrate that the symptom relief achieved within the first few months after cervical ADR can last for many years.
Spinal implant companies are constantly looking for new ways to innovate, push the envelope and provide a better solution for patients. Motion preservation devices, by nature, allow patients a better outcome, and many companies are investing heavily in new technology to make this happen. Spinal fusions don’t offer the same opportunity for innovation as motion preservation and, thus, a cycle of companies battling for awareness, market share, and improved outcomes has been created thus having a positive impact on patient outcomes.
Wait for further articles on lumbar motion preservation techniques! Meanwhile we got your Back!