Intramedullary arachnoid cyst: 3-year follow up after bilateral dorsal root entry zone myelotomy

Abstract

Spinal arachnoid cysts are relatively uncommon an intramedullary location is believed to be extremely rare. A 35 year old woman, admitted with progressive weakness in the lower limbs, was diagnosed as having a thoracic intramedullary arachnoid cyst. After bilateral dorsal root entry zone myelotomy procedures and wide fenestration was performed, there was a dramatic and immediate recovery. This is the first intramedullary arachnoid cyst reported to be treated by this approach and the long term outcome discussed.

An Adult Cervical Intramedullary Arachnoid Cyst: Case Report and Review

“…None of these showed worsening of the preoperative neurological deficits. Instead all the patients presented a clear improvement during the first weeks following the procedure, which was independent from the duration or severity of symptoms [3,4,[6][7][8][9][10][11][13][14][15][16][17][18]. The authors report the only published case of intramedullary adult arachnoid cyst with neurological stability during follow-up (five years), and managed with a wait and scan approach.…”

“…All cases of purely intramedullary arachnoid cysts reported in the literature showed a growth overtime accompanied by sudden neurological deterioration, requiring immediate surgical evacuation [3,4,[6][7][8][9][10][11][13][14][15][16][17][18]. To date, there is no existing literature on a quiescent intramedullary arachnoid cyst detected incidentally in an asymptomatic subject [10].…”

“…Most cases are incidental findings detected on imaging evaluations for other reasons [6]. In a series of 99 children, held by Campagna et al between 1 years and 6 years of age that underwent decompressive surgery for spinal cord compression, only 1 case it was an arachnoid cyst [12].…”

“…There are only six cases reported in the literature, in patients over 18-year-old, all with thoracic location [6][7][8][9][10][11].…”

“…The pathogenesis of these lesions remains unclear, and various causes, including congenital, traumatic or inflammatory, are proposed [5]. Nabors et al classified them, according to their location, as: Type I-extradural without spinal nerve root fibers; Type II-extradural with spinal nerve root fibers; Type III-intradural [6]. Extradural cysts arise from arachnoid herniation through small flaws of the dura mater, while the intradural develop mainly from changes of the arachnoid trabeculae.…”