Abstract
Introduction: Progression of lumbosacral spondylolisthesis during adolescence is not uncommon, but it is rare in adults. Structural changes in adolescent spondylolisthesis have been reported as possibly predictive and contributory to progression.
Aim: To review the structural changes that occur with and possibly contribute to slip progression in lumbosacral spondylolisthesis.
Methods: The radiographs of 42 patients with lumbosacral spondylolisthesis who had been followed for a mean period of six years were reviewed. The following radiological parameters were determined from the initial and latest radiographs:
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Percentage slip
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Slip angle
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Rounding of the sacrum
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Trapezoid index of L5 vertebral body
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Progression of a lumbar lordosis was defined as an increase in slip of 5% or more.
Results: Strong correlations (p< 0.01) existed between all radiological parameters at the time of the initial examination and at follow-up. Changes in percentage slip over time correlated with changes in all radiological parameters (p< 0.01). Slip progression correlated with increased slip angle (p< 0.01), increased trapezoid index (p< 0.05), and increased lordosis (p< 0.01) but not with age (p=0.16), adolescence (p=0.10), gender or with spondylolysis. The risk of slip progression was greatest for adolescents with an initial slip of 30% or more (p=0.13, Odds Ratio=5.7).
Conclusions: Slip progression in lumbosacral spondylolisthesis was associated with corresponding proportional structural changes in the sacrum and the L5 vertebral body, possibly related to growth and remodelling. The tendency to progress was greatest in adolescents with slips of greater than 30%. This relationship was sufficiently strong to consider prophylactic fusion.
The abstracts were prepared by Professor A. J. Thurston. Correspondence should be addressed to him at the Department of Surgery, Wellington School of Medicine, PO Box 7343, Wellington South, New Zealand
