Los quistes aracnoideos extradurales espinales son lesiones poco frecuentes. Clínicamente se caracterizan por un cuadro mielopático progresivo, asociado o no a crisis radiculares. Para su diagnóstico radiológico las técnicas de resonancia magnética actuales posibilitan definirlos adecuadamente y conocer su localización topográfica. Los antecedentes patológicos del paciente son esenciales para establecer se etiología encontrándose en muchos casos una historia de trauma espinal, cirugía y menos frecuentemente anomalías congénitas asociadas. El tratamiento en la mayoría de los casos es quirúrgico.

Presentamos el caso de un paciente de 35 años con antecedentes de una hemisección medular dorsal por arma blanca hace dos años. Evolutivamente se deterioran sus funciones motoras presentándose con una paraparesia espástica. Los estudios radiológicos mostraron la presencia de la lesión quística extradural comprimiendo el cordón medular a nivel dorsal (D3-D4). Se realizó cirugía descompresiva y se identificó un desgarro meníngeo a ese nivel que fue suturado. La evolución postoperatoria fue satisfactoria.

El tratamiento quirúrgico efectivo de estas lesiones está dado por la detección del defecto meníngeo y su cierre.

Extradural arachnoid spinal cysts are unfrequent lesions that are associated with spinal trauma, surgery and less frequently with congenital anomalies. The clinical manifestations are similar to those seen with other compressive spinal cord lesions. Magnetic resonance techniques allow to diagnose correctly this pathology and to define its thopographic situation. The pathologic history of the patient is essencial to establish the ethiology. Surgery is the elective treatment in most cases.

The patient is a 35 years old man who has a medical history of penetrating spinal trauma two years ago. In that instance he suffered an unilateral spinal cord section at D2-D3 level with the corresponding Brown Sequard syndrome. A small wound was detected at the skin dorsal level and it was closed without difficulties. At the beginning, he improved his motor right leg function with rehabilitation and vitamins. After two years of good recovery he came to our hospital suffering a neurological deterioration of six months of evolution. The physical examination revealed an spastic paraparesis. Magnetic resonance was performed demonstrating a cystic extradural collection compressing the spinal cord at D3-D4 level. Surgical decompressive treatment allowed to excise the cyst and it was possible to define a dural tear that was closed successfully. The outcome was good with restoration of the initial motor function that he had after the spinal trauma.

Surgical management of postraumatic epidural arachnoid spinal cyst allows to detect the meningeal tear and to close it, which is highly effective on these kinds of lesions.