Spinal Intradural Arachnoid Cysts in Adults: An Institutional Experience and Literature Review.

Background: Adult spinal intradural arachnoid cysts are rare pathologic entities with an unclear etiopathogenesis. These lesions can be dichotomized into primary (idiopathic) or secondary (related to inflammation, intradural surgery, or trauma) etiologies. Limited series have depicted optimal management strategies and clinical outcomes.

Objective: To illustrate our experience with spinal intradural arachnoid cysts and to present a literature review of surgically treated cysts to elucidate the clinical and anatomic differences between etiologies.

Methods: Institutional review revealed 29 patients. Various data were extracted from the medical record. Initial and follow-up symptomatologies of the surgical cohort were compared. The literature review included case series describing cysts managed surgically.

Results: From patients treated surgically at our institution (22), there was a significant reduction in thoracic back pain postoperatively ( P = .034). A literature review yielded 271 additional cases. Overall, primary and secondary lesions accounted for 254 and 39 cases, respectively. Cysts of secondary origin were more likely localized ventral to the spinal cord ( P = .013). The rate of symptomatic improvement after surgical intervention for primary cysts was more than double than that of secondary cysts ( P < .001). Compared with primary etiologies, the rates of radiographic progression ( P = .032) and repeat surgery ( P = .041) were each more than double for secondary cysts.

Conclusion: Surgical intervention for spinal intradural arachnoid cysts improves thoracic back pain. The literature supports surgical intervention for symptomatic primary spinal intradural arachnoid cysts with improved clinical outcomes. Surgery should be cautiously considered for secondary cysts given worse outcomes.