Minimally invasive management of a spinal arachnoid cyst with ultrasound-assisted catheter placement: illustrative case.

backgroundSpinal arachnoid cysts are cerebrospinal fluid-filled sacs that are frequently located within the thoracic spine and can lead to symptoms due to direct compression of the thoracic spinal cord. These lesions are typically treated with laminectomy and fenestration of the cyst, with or without shunting. However, with recurrence, treatment is often more complex and sometimes requires re-exposure and fenestration or shunting. OBSERVATIONS: Here, the authors describe a 57-year-old female with a thoracic intradural arachnoid cyst that recurred despite extensive and initially successful fenestration. Given the failure of fenestration, the authors instead attempted to place a cystoperitoneal shunt. Given how extensive her laminectomy was, the authors elected to perform the procedure under ultrasonic guidance to avoid the large incision required for open shunt placement. The procedure was successful, with gradual improvement in the size of the arachnoid cyst as well as symptomatic improvement. LESSONS: Here, the authors present a unique minimally invasive technique to treat recurrent spinal arachnoid cysts. They successfully demonstrated the feasibility and safety of this approach in shunting the cyst while avoiding the extensive re-exposure often required in such complex cases. https://thejns.org/doi/10.3171/CASE24461.