Disk Replacement or Spinal Fusion: What’s the Long-Term Benefit?

Drs. Lin and Wang present a review of the total disc replacement (TDR) from its beginnings in the 1950s until today. Surgeons refer to TDR as a total disc arthroplasty (TDA).

TDA has become an alternative treatment option to spinal fusion. The goals of TDA are to: 1) remove the source of pain, 2) maintain disc height, 3) provide spinal stability, and 4) preserve motion.

The design of the TDA has changed over the years. Studies have shown what works and what doesn’t. Today’s TDAs are a ball and socket style. They must last the lifetime of the patient. The materials must be acceptable to the human body to avoid rejection. The disc must not break down or shed particles called debris.

There are two main lumbar discs available in the United States (Charité III and ProDisc-L). Other implants are being studied. Each design has its own specific unique qualities.

Materials, load-bearing surface, and mobility or constraint are just a few things that must be considered. How and where the implant moves and how it is fixed to the bone are also important. The authors review each type of TDA in detail.

TDAs for the cervical spine are also under investigation. Although cervical fusion is very successful, problems with swallowing and degeneration of the adjacent segment can occur. On the other hand, problems with disc replacements can also occur. Cervical implants are new enough so that only short-term results are available.

The authors pose many questions for the future. Will TDA replace spinal fusion? Can these implants last a lifetime without complications? What is the best design? What are the long-term benefits?

In time, gene therapy and human growth factors may make it possible to regenerate diseased discs making even TDAs a treatment of the past. Ongoing studies must continue to analyze results. The true place of TDAs in the treatment of back pain is yet to be decided.