Study Design. Systematic review of published prevalence of adjacent segment degeneration (ASD) after spine surgery.
Objective. To evaluate the prevalence of ASD in patients after cervical and lumbar spine surgery.
Summary of Background Data. ASD is a common complication after spine surgery in long-term follow-up. A large body of literature has been reported on the topic, but no meta-analysis of the epidemiological data on ASD has been published
Methods. We searched the MEDLINE until March 2012 published in English language that reported the prevalence of ASD after spine surgery. We determined the ASD rates by calculating proportions and 95% confidence interval (CI) for each study and then pooled the data to derive a pooled proportion and 95% CI.
Results. A total of 94 studies with 34,716 patients from 19 countries were included. The occurrence of radiograph ASD ranged from 4.8% to 92.2%, and the pooled prevalence was 29.3% (95% CI, 22.7%–35.8%) by the random-effects model. The occurrence of symptoms ASD ranged from 0.0% to 30.3%, and the pooled prevalence was 7.4% (95% CI, 6.4%–8.5%). In cervical position, the occurrence of radiograph ASD and symptoms ASD was 32.8% (95% CI, 17.8%–47.9%) and 6.3% (95% CI, 4.8%–7.8%); in lumbar position, the occurrence of radiograph ASD and symptoms ASD was 26.6% (95% CI, 21.3%–31.9%) and 8.5% (95% CI, 6.4%–10.7%). In the 0.5- to 2- or less, more than 2- to 5- or less, and more than 5- to 20- or less year diagnosis time, the radiograph ASD prevalence was 21.8% (16.0%–27.6%), 33.6% (21.8%–45.4%), and 37.4% (10.7%–64.1%), respectively; and the symptoms ASD prevalence was 6.5% (4.8%–8.1%), 12.1% (8.2%–16.0%), and 3.2% (2.5%–4.0%), respectively.
Conclusion. Spine surgery is associated with significant risk of ASD. These figures may be useful in the estimation of the burden of the ASD after spine surgery.