Spontaneously stabilized severe dysplastic spondylolisthesis without operation: long-term follow-up of a preteenage patient.

Surgical management is the accepted treatment choice for grade III or IV spondylolisthesis, and many satisfactory clinical and radiologic follow-up results have been reported. Very little, however, has been written about long-term results in preteenage patients in whom dysplastic spondylolisthesis has been treated nonoperatively, especially in those who have > or =50% displacement of the fifth lumbar vertebra on the sacrum. We report an unusual case of spontaneous stabilization of severe dysplastic spondylolisthesis in an 8-year-old girl who presented with grade III spondylolisthesis of L5-S1 and was followed up for >14 years in the absence of surgical intervention. On presentation, she complained of a restriction in forward bending and tightness of hamstrings, but she was undisturbed in her daily activities. Initial radiographs showed severe dysplastic spondylolisthesis; however, magnetic resonance imaging (MRI) performed at age 9 years showed that the amount of listhesis was much less than that seen in the initial radiograph. Routine radiographic follow-ups were chosen over early operative measures until she became a teenager. There was no change in the slip, and unusually a gradual ossification of the cartilaginous promontory of the S1 and the posterior lip of the L5 was observed. At 22 years old, the patient is asymptomatic and not conscious of her cosmetic appearance. Surgical treatment has generally been indicated for patients with grade III or IV spondylolisthesis, because slippage progression has been noted in most reported cases. However, MRI may be a tool for predicting which dysplastic spondylolisthesis cases are more likely to progress and therefore circumvent surgical intervention, while maintaining an excellent outcome.