Most arachnoid cysts are found incidentally and remain constant in size, leading many physicians to recommend conservative treatment. When no symptoms are present, no treatment may be necessary and affected individuals may be periodically monitored. If symptoms arise, a cyst can be reevaluated.

When treatment is necessary the specific therapy used depends upon whether symptoms are present, the size of the cyst and the specific location of the cyst within the skull.

In cases where treatment is recommended, therapy traditionally consists of one of two procedures – an open craniotomy fenestration or ventriculoperitoneal shunting.

During a craniotomy fenestration, a portion of the skull is removed to give a surgeon access to the cyst, where multiple openings are made in the cyst wall, (fenestrations), to allow cerebrospinal fluid to drain into the subarachnoid space where the fluid is reabsorbed into the surrounding tissue. Alternatively, some cases may be treated by surgically inserting a device (shunt) into the cyst to provide drainage either into the ventricular system of the brain or into the abdominal cavity. This will drain the cyst and provide an adequate passageway for cerebrospinal fluid to circulate.

More recently, advancements in minimally invasive brain and skull base surgery have evolved these traditional procedures into fully endoscopic techniques, distinguished by shorter operating times, fewer complications, excellent outcomes with faster recovery and overall decreased patient morbidity. While the approach varies depending on the size and location of the arachnoid cyst, fully endoscopic surgical management has provided the surgeon with superior access for either fenestration, or in other cases, resection of the cyst without the complications and risks associated with brain manipulation or retraction. Few facilities provide minimally invasive, endoscope assisted fenestrations, endoscopic shunt placement and endscope assisted or fully endoscopic resection of arachnoid cysts as treatment when indicated.

Spinal arachnoid cysts may be treated by the complete surgical removal (resection) of the cyst, if possible. Surgery generally leads to a resolution of symptoms. In some cases, complete surgical removal of a spinal cyst is not possible. In such cases, fenestration or shunting of the cyst to drain the fluid may be necessary.