Spinal fusion in the treatment of chronic low back pain: rationale for improvement.

Results following fusion for chronic low back pain (CLBP) are unpredictable and generally not very satisfying. The major reason is the absence of a detailed description of the symptoms of patients with pain, if present, in a motion segment of the spine. Various radiological findings have been attributed to discogenic pain, but if these radiological signs were really true signs of such pain, fusion would have been very successful. If discogenic pain exists, it should be possible to select these patients from all others within the CLBP population. Even if this selection were 100% perfect, however, identification of the painful segment would remain, and at present there is no reliable test for doing so. Regardless of whether an anterior or posterior type of fusion is performed, or even if artificial discs are used, solving the puzzle of pain associated with the presumed segmental disorder must be the primary goal.