Pulsatile wall movement of spinal arachnoid cyst deteriorates spinal cord symptoms: report of three cases

Symptomatic spinal arachnoid cyst is a rare disease and the pathophysiology causing spinal cord symptoms has not been well clarified. The authors report three symptomatic cases of spinal arachnoid cyst at the thoracic level. These patients, aged from 70 to 73 years, showed progressive gait disturbance for a few months before admission. Phase-contrast cine magnetic resonance imaging demonstrated significant compression at the rostral side of the cyst during the diastolic phase of the cardiac cycle. Intraoperative ultrasonography demonstrated that the maximum expansion of the cyst and compression of the dorsal spinal cord occurred when the cerebrospinal fluid moved rostrally during diastole. All patients showed good improvement of their symptoms after surgical removal of the arachnoid cyst. This report proposes the pathophysiology that the pulsatile enlargement of the arachnoid cyst during diastolic cardiac phase can be an important factor for deterioration of spinal cord symptoms.