THE NATURAL HISTORY OF SPONDYLOLYSIS AND SPONDYLOLISTHESIS:  45-YEAR FOLLOW-UP EVALUATION.  Spine, Vol. 28, No. 10, May 15, 2003.

            William J. Beutler, MD et al

ABSTRACT

It has been documented conclusively that there is a zero percent incidence of spondylolysis and spondylolisthesis in the fetal stage, and the rate increases to approximately 6% for the general population.  There has been study and debate regarding the progression of the problem, and this study was initiated in 1955 to determine long-term progression of the conditions.

Between 1954 and 1957, a large group of Pennsylvania children in the first grade were radiographed to find the rate of the conditions, and a total of 22 were found to be positive for lytic defect of the pars interarticularis.  By adulthood, more lytic lesions developed in some children raising the total to 30, or 6%.  Now the study population is older than 50, and over the decades they have been studied, radiographed, and are now receiving MRI and SF-36 questionnaires.

Of the 30 subjects, 22 had bilateral pars defects, while 8 had unilateral defects, most being at L5.  3 subjects, all with unilateral defects, showed healing at later years in life (31, 31, and 28 years) via tomography and radiograph.  Long-term MRI images of the unilateral group revealed that only 2 progressed to having disc degeneration.  In the bilateral group, 4 never developed spondylolisthesis, and none revealed any healing like the unilateral group did.  The overall ratio of male to female was 2:1, and the degree of slippage varied in groups that had early slippage, and those who developed the condition in their teen years. 

Overall slippage in those who had either early spondylolisthesis or late was greatest in their early years, with a slip progression of 7% in the first decade of follow-up, 4% in the second and third decades, and 2% in the fourth decade.  Those female subjects who became pregnant revealed no association with any low back pain, with only one reporting pregnancy pain due to situations not even related to the lumbar spine. 

Overall, unilateral defects were not associated with spondylolisthesis or disability, and those with bilateral defects followed a clinical course with regards to DJD, DDD, etc. that was similar to the normal population.  The slip progression continued to slow as they reached the age of 50, and no subject reached a slip degree of 40%.  Only a small percentage of those with bilateral defects will develop symptoms.

COMMENTS

In school, we are often taught that spondylolisthesis patients are to be handled very carefully, avoiding all extension at all costs.  I have found that over time and with education, this is not the case.  Granted, someone with Grade III or IV should not be performing prone press-ups, but you probably would not even see a Grade IV unless something is preventing them from surgery. 

I once worked with a PT who was a certified McKenzie instructor, who also had I believe a Grade II slippage, and he performed extension all the time, with good relief of symptoms.  As this article indicates, the progression slows as age increases.  A 40-year-old person with Grade I spondylolisthesis and low back pain would be safe to do simple extension exercises, such as prone on elbows and back extensor strengthening. 

The clinical exam of these patients, especially the younger ones with unilateral pars defects, will usually reveal excessive movement during extension at the level involved.  As covered in the treatment section of this website, manual therapy to increase segmental extension of the surrounding vertebrae works quite well, and decreases the forces at the involved level. 

It would be safe to assume that most of these patients lived normal lives during the course of this study, perhaps playing tennis, softball, high school sports, etc.  The fact that progression was slow, and that symptoms were not worse than the general population, indicates that this condition may not be as fragile as we have been led to believe.  I doubt that some general therapy procedures would surpass the forces that normal life places on the spine (not counting high force manipulation or mobilization to the involved segments, which could cause damage).  It is also possible that back pain in some of these patients may be due to a completely unrelated situation, and the spondylolisthesis or pars defect was implicated simply because it was there and obvious.