Artificial Disc Replacement a New Alternative to Spinal Fusion Surgery

About 80% of people have back or neck pain at some point in their lives, and it is second only to cold and flu in the number of doctor's visits it prompts. Fortunately, most of the pain takes care of itself, along with a little help from pain killers. But for some, the pain only gets worse - so bad, in fact, that performing even simple household chores becomes almost impossible. An emerging type of spinal surgery, called total disc replacement promises new hope for some of these sufferers.

One of the most common causes of chronic back pain is an injured or degenerated intervertebral disc. The disc is the soft cushioning structure located between the individual bones of the spine, called "vertebra." It is made of cartilage-like tissue and consists of an outer portion, called the annulus, and an inner portion, called the nucleus. In most cases, the disc is flexible enough to allow the spine to bend. A damaged or degenerated disc not only losses its cushioning function, it also becomes a pain generator during simple activities like bending and carrying things.

Typically, surgery is not considered for disc-related pain unless the pain has been severe for a prolonged period (typically over 6 months) and the patient has gone through non-operative treatments (such as active physical therapy, medication, injections, acupuncture and activity modification). The most popular back surgery is spinal fusion, where surgeons remove the disc that's causing pain and fuse the adjacent vertebrae together with rods, screws and a bone graft.

The benefit of spinal fusion is it that can eliminate disc pain by removing its source. The downside is that it puts additional stress on the discs adjacent to the fusion, which could set a person up for more back problems later. This concern has led doctors to advise young and active patients with chronic against spinal fusion. Most of these patients had no choice but to bear with the pain and have a more sedentary lifestyle. In addition, there is a long rehabilitation time which may take 4 to 9 months.

Considering body function, it is a pity to sacrifice the flexibility of the spine. Today, no one would offer arthrodesis (joint fusion) as a treatment for arthritis of the hip or knee joint. For these joints, total joint replacement works quite well and has been the standard of care for decades.

As an alternative to spinal fusion, a variety of artificial intervertebral discs have been investigated for the past 30 years. This approach also referred to as total disc replacement or spinal arthroplasty is expected to have the following advantages over spinal fusion:

  • Provide pain relief and increased patient activity levels
  • Restore disc space height and lordosis
  • Maintain segmental spinal motion and flexibility
  • Eliminate postoperative fusion problems such as extensive recuperation time, bone graft donor site pain, and pseudarthrosis

Patients generally experience an immediate relief of their chronic pain and can resume everyday activities that they could not do for years. Having said this, in some cases spinal fusion may still be necessary and this decision can only be made in the light of X-rays, MRI and the consultation with an experienced spinal surgeon.

While only one artificial disc, the SB Charite III lumbar disc was FDA approved in the United States only last year, the Prodisc lumbar artificial disc replacement has been available in Singapore since October 2002. Both devices have been used in Europe for the past 10 to 20 years.
A. SB Charite III B. Prodisc II

These prostheses consist of two endplates made of high quality cobalt chrome alloy, an implant material which has been proven to be extremely well tolerated by the body. A polyethylene plastic core is inserted between these endplates to allow near normal spinal segmental motion and flexibility. Much like the artificial hip or knee system that relies on metal and plastic to replicate normal movement, these spinal prostheses are designed to mimic the function of the healthy discs.

As with any surgery, there are risks associated with disc replacement. Possible complications include infection, injury to blood vessels, nerve injury, dislodgement of the device and retrograde ejaculation and death.

Recently artificial disc replacement for treatment of neck pain has also been available in Singapore. Cervical arthroplasty is indicated for the treatment of radiculopathy and myelopathy at one or two levels, where the nerve or the spinal cord gets compressed by herniated intervertebral disc. Pain relief is immediate with clinical success of about 85% and device range of motion averaged 7.40.

This expertise is now available at Raffles Hospital. For more information, kindly contact us at
Tel: (65) 6311 1222 or Email: enquiries@raffleshospital.com.