The Clinical Study On 12 Patients With Spinal Extradural Arachnoid Cyst And Literature Review

Background and objective:Spinal extradural arachnoid cyst (SEAC) is a rare disease that that accounts for approximately 1 to 3% of all primary spinal space-occupying lesions. Most of the literatures on the disease are case reports. Clinical study and summer is limited, which addresses the feature, diagnosis and treatment of SEAC. This study was designed to discuss the clinical feature diagnosis, management and prognosis on the basis of experience of 12 paitents with SEAC.Methods:Clinical dates of 12 patients with SEAC from January,2003 to December,2008 were collected. All patients were retrospectively analyzed in the Department of neurosurgery, Second Affiliated Hospital, Zhejiang University school of Medicine. Then we reviewed the related literature about SEAC.Results:In the 12 patients aged from 9 to 56 years old, with average age of 28.17 years old. Seven were male and five were female. Among those patients, seven were adolescents with average age of 12.43±2.44 years old and five were adults with average age of 50.2±6.3 years old. Seven patients presented with paraparesis. Five patients had sensory disturbances. Three patients suffered both limb weakness and sensory dysfunction. Five patients showed the corresponding nerve root pain. One child complained urinary incontinence. MRI scans of 12 cases showed arachnoid cyst in cervical spine 1 case (8.3%), in thoracic spine 7 cases (58.3%) and in lumbar spine 2 cases (16.7%) and in sacral segment 2 cases (16.7%). All extradural lesions appeared hyperintense on T2WI images, but hypointense on T1 WI similar to the features seen for cerebrospinal fluid. In seven adolescents, five patients (71.42%) had thoracic spinal SEAC. One (14.29%) had cervical SEAC. One (14.29%) had SEAC in thoracolumbar segments. In five adult cases, two adult patients (40%) had SEAC in the thoracolumbar spine and three patients (60%) had SEAC in the lumbosacral segments. Eleven patients received surgical intervention. Histological examinations confirmed the diagnosis of arachnoid cyst. Follow-up for 3.16 years on average did not show any recurrence of SEAC.Conclusions:SEAC is rarely reported in the literature. It is a complex disorder. Excision of the SEAC can lead to a favorable outcome.