Natural History of Cervical Degenerative Spondylolisthesis.

Study Design: Retrospective observational and case-control study.
Objective: To determine the risk factors for progression of degenerative listhesis by comparing patients with and without progression at greater than 5-year follow-up.
Summary of Background Data: The previous study with 2- to 7-year follow-up showed that degenerative spondylolisthesis of the cervical spine did not progress. Longer-term follow-up may reveal that these patients actually do progress over time.
Methods: We identified 218 patients with greater than 5-year follow-up without surgery. They were categorized as either having or not having cervical spondylolisthesis. We defined spondylolisthesis as the presence of greater than 2 mm of translation in standing neutral lateral radiographs of the cervical spine at the initial evaluation. The control group at baseline was those without spondylolisthesis. Progression of translation was defined as greater than 2 mm of additional translation on the final standing neutral radiograph.
Results: The mean follow-up duration was 6.4 ± 1.0 years (range: 5-9.4 yr). Progression of translation was found in 20 patients (9.2%), including 4 patients in the spondylolisthesis group and 16 patients in the control group. Progression of translation was not related to the presence of spondylolisthesis or the severity of translation at the initial evaluation, but was more common in the elderly and in the patients with anterior translation than those with posterior translation at the initial evaluation. In addition, progression of spondylolisthesis was not correlated with any change of symptoms.
Conclusion: Progression of cervical spondylolisthesis is not related to the presence of spondylolisthesis at baseline.
Level of Evidence: 4.