Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P45. The prevalence of incidental and symptomatic lumbar synovial facet cysts

Abstract

BACKGROUND CONTEXT The prevalence of symptomatic and asymptomatic synovial facet cysts in the lumbar spine has been incompletely established, and although many studies demonstrate an association with degenerative spine disease, no cumulative increase in prevalence of synovial facet cysts with increasing age has been presented. PURPOSE To assess the prevalence of incidental (ie, asymptomatic) and symptomatic lumbar synovial facet cysts on MRI. Secondarily, we will assess if the prevalence of lumbar synovial facet cysts increases with age and what other factors are associated with its prevalence. In addition, we will assess differences in patient and cyst characteristics between asymptomatic and symptomatic facet cysts. STUDY DESIGN/SETTING Retrospective cohort study from two affiliated tertiary care referral centers for spine disease. PATIENT SAMPLE A total of 19,010 consecutive patients who underwent a dedicated lumbar spine MRI between 2004 and 2015. OUTCOME MEASURES Symptomatic and asymptomatic facet cysts. METHODS A symptomatic cyst was defined as a cyst with symptoms of radiculopathy on the same side as the cyst. The prevalence of incidental, symptomatic, and overall synovial facet cysts was reported as a percentage with 95% confidence interval (95% CI). Multivariable logistic regression analysis was used to assess if age, sex, race, and indication for MRI were associated with having a facet cyst. Generalized estimating equation analysis was used to assess differences between symptomatic versus asymptomatic synovial facet cyst: age, sex, race, side, level, cyst size, and cyst location. RESULTS The overall synovial facet cyst prevalence was 6.5% (95% CI: 6.1–6.8) [1,228/19,010]. These 1,228 patients had 1,553 synovial facet cysts of which 46% cysts (721/1,553) were incidental and 54% cysts (832/1,553) were symptomatic. The prevalence of having one or more incidental synovial facet cysts was 2.7% (95% CI: 2.5%–3.0%) [518/19,010], the prevalence of having one or more symptomatic synovial facet cysts was 3.2% (95% CI: 3.0%–3.5%) [617/19,010], and the prevalence of having both one or more incidental and one or more symptomatic synovial facet cysts was 0.49% (95% CI: 0.39%–0.59%) [93/19,010]. Increased age was independently associated with a higher likelihood of having a synovial facet cyst (odds ratio [per 10years increase in age]: 1.24, 95%CI: 1.20–1.29, p CONCLUSIONS Approximately 1 in 15 patients has at least one synovial facet cyst and about half of them are symptomatic and half are asymptomatic. Having a facet cyst — symptomatic and asymptomatic — is strongly associated with increased age supporting the theory that degenerative spine disease underlies development of facet cysts. Large cyst size and anterior location of the cysts are associated with an increased likelihood of having neurological symptoms.