Surgical Management of Spinal Arachnoid Cysts in Adults

BACKGROUND: Spinal arachnoid cysts (SACs) are uncommon lesions in the spinal canal. They are usually asymptomatic, but can occasionally cause mass effect leading to neurologic symptoms. They can be congenital or secondary to a variety of causes. They can produce a variety of neurologic symptoms including pain, weakness, sensory changes, incontinence, and more. Surgical intervention may be necessary when SACs cause symptomatic mass effect. METHODS: Thirteen consecutive patients who underwent surgical intervention for an SAC were retrospectively reviewed. The data included presenting symptoms, imaging findings, neurologic status, and follow-up. RESULTS: Of the 13 patients, the majority of cases were located in the thoracic spine (54%) and all but one case were located dorsally or dorsolaterally. Furthermore, 38% were located extradurally and 54% were located intradurally. Pain (80%) was the most common presenting symptom. Most patients had improvement or complete resolution of their symptoms after intervention. Extradural SACs and their capsules were completely resected, whereas intradural SACs underwent fenestration. No complications occurred in this series. CONCLUSIONS: SACs are usually asymptomatic, but rarely cause mass effect and neurologic deficits requiring surgical intervention. Surgical intervention is tailored to the position of the cysts' dorsal or ventral locations. Pain and weakness are the most likely symptoms to improve, whereas sensory symptoms are least likely to improve.