This promising new procedure is a boon for all those suffering from severe and intractable neck pain. It has revolutionized the approach used for treating patients with severe longstanding cervical spondylitis, whiplash injuries, cervical disc prolapse, offering them a better quality of life. Also known as artificial disc replacement, this technique is fast becoming popular amidst surgeons and patients alike because of its excellent results. It is considered superior to cervical spine fusion surgeries as it maintains normal neck motion post operatively and ensures early return of patient to normal activities. In this procedure a stainless steel disc with a ball in trough design is inserted between the affected cervical vertebrae. This helps to simulate natural neck movements. The patient stays in the hospital for 1-2 days and resumes work in 45 days.
Working Anatomy of Cervical Spine
The cervical spine consists of 7 cervical vertebrae named C1, C2, C3, C4, C5, C6, C7 with shock absorbing intervertebral disc in between them. These discs allow for the smooth rotating and bending movements of the cervical spine. With age these discs lose their water content and get compressed between the vertebrae which may lead to herniation of disc contents. Along with this there is wear and tear of the vertebrae causing formation bony outgrowths known as (osteophytes). The prolapsed disc can compress the spinal cord within the spinal canal (myelopathy) or the exiting nerve roots at the intervertebral foramina (lateral openings between each vertebral pair) causing radiculopathy (radiating pain in the arm).
Objective of the Procedure
The cervical segments C4- C5, C5-C6, C6-C7 are more vulnerable to disc prolapse and spondylitis due greater mobility at these joints. Disc prolapse results in reduction of intervertebral distance which causes pressure on the exiting nerve roots at intervertebral foramina. Disc replacement surgery aims at reducing the symptoms of degenerative joint disease. Replacing the damaged disc with an artificial implant or prosthesis, restores the normal distance between the two vertebrae and relieves the pressure on the nerve roots.
Why is Cervical Disc Replacement Surgery required?
A large number of people nowadays face neck, shoulder and/ or pain in the arms mainly because of the abnormalities in the neck. These complaints can be signs of disc herniations or disc degeneration, and/or arthritis of the neck.
The cervical spine is composed of vertebral bodies and intervertebral discs. These discs wear out with time causing pain and other symptoms and are referred to as degenerative disc disease, a subgroup of which includes cervical disc herniations. This means the disc becomes compressed, frayed, and/or herniates into the adjacent spinal canal where it can press on nerves or the spinal cord.
Most patients with these types of symptoms do not need surgery and improve with conservative like anti-inflammatory medications, physical therapy, or cold/heat therapy. However, if a person continues to have significant neck pain and/or radicular arm pain, he or she may be a candidate for cervical spine surgery. An anterior discectomy and fusion is the most common operation for treating patients with symptoms related to a degenerative or herniated disc in the neck.
Cervical Disc Replacement Surgery- The Procedure
The procedure for cervical disc replacement surgery consists of removing the problem disc entirely and replacing it with a piece of bone taken either from the patient's hip and a metal plate with screws and/or a cervical collar may also be used to help hold the bone in place and to allow this segment of the neck to fuse together. The purpose of an anterior cervical discectomy and fusion surgery is twofold:
- To remove the offending agent—either the herniated disc or the osteophytes that are compressing the nerves and/or spinal cord.
- To eliminate motion by inducing a fusion at the disc space where the disc has been removed, aided by the use of bone grafts and possibly plates/screws, etc. and thereby creating stability and/or eliminating pain associated with the motion.
This type of surgery typically improves the pain in over 90% of people with one-level disease. However, there may be complications in using bone grafts in pursuit of a fusion. Harvest of one's own bone may be associated with both acute and potentially long-term pain from the donor site. Any type of bone graft may fail to heal, resulting in a so-called 'non-union', which may require another fusion operation.
Also, by fusing a segment of the spine, the levels of the spine above and below the fused area are now forced to absorb more load since there is no longer any intervening motion shock absorption. These adjacent levels will then wear out and become symptomatic in more than 25% of these patients within ten years, meaning possibly more surgery. This is called adjacent-segment degeneration.
The development of artificial cervical discs is intended to accomplish the same objectives as the traditional decompression and fusion surgery in terms of providing pain relief and stability, but with fewer drawbacks. For example, the cervical artificial disc does not include the potential complications involved with using bone graft (e.g. 'non-unions') and theoretically should lessen the risk of developing adjacent-segment disc degeneration or disease.
Post operative Recovery and Rehabilitation Period
The patient stays in the hospital for 1-2 days and resumes work in 45 days post operatively. Avoid bending neck backwards. A brace or soft collar may be recommended after the operation to support the neck muscles. Physical therapy may be prescribed 1-2 weeks after surgery which has to be done on outpatient basis. The therapy will initially start with pain relieving modalities such as ice, electrical stimulation to reduce pain followed by gentle active exercises. Gradually gentle stretching, strengthening and endurance exercises to the neck muscles are introduced. The therapist gives instructions on how to maintain the neck postures during various tasks of daily living. This is followed by a home exercise program.
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