Global incidence of spinal perineural Tarlov’s cysts and their morphological characteristics: a meta-analysis of 13,266 subjects

Background Spinal perineural Tarlov’s cysts (TCs) are considered incidental findings that occasionally might exert pressure upon nerve roots and correspond with patients’ signs and symptoms. Purpose of this meta-analysis is to deliver global incidence and characteristics (location, size, and shape) of TCs. Methods Following PRISMA checklist, all major databases were searched by two authors for radiologic studies reporting incidence and morphologic features (location, size, and shape) of TCs. Anatomical Quality Assessment tool was applied for risk of bias evaluation. Meta-analysis of random-effects model was employed. Subgroup analysis for regional distribution, gender, sacral levels, age, correspondence with symptoms, and persistent genital arousal disorder (PGAD) were planned ahead. Results 22 radiologic studies of level 3 evidence involving 13,266 subjects were included. Global pooled prevalence of TCs was 4.18% (95% CI 2.47–6.30). Mean pooled sagittal diameter was 11.86 mm (95% CI 10.78–12.93). Sacral cysts strongly prevailed over the other segments. Of the sacral, S2 level was the most common (46.7% [95% CI 29.4–60.5]). Geographically, the highest incidence was found in Europe (6.07% [95% CI 1.49–13.00]), followed by North America (3.82% [95% CI 0.49–9.44]), and Asia (3.33% [95% CI 1.52–5.75]). TCs were more common in women than in men (5.84% vs 3.03%, p