title: Surgical treatment of spinal extradural arachnoid cysts in the thoracolumbar spine.
abstract: BACKGROUND
  Because an idiopathic spinal extradural arachnoid cyst (SEAC) is rare, its optimal surgical treatment remains controversial.
  
  
  OBJECTIVE
  To evaluate the results of surgical treatments for SEACs and to clarify features of the disease associated with poor outcomes.
  
  
  METHODS
  Twelve patients with SEACs who underwent surgery at our hospital between 1988 and 2008 were examined retrospectively. The mean follow-up period was 4.7 years. Total resection of the cyst was performed in 7 patients and closure of the dural defect without cyst resection in 5 patients. Surgical outcomes were evaluated with regard to the duration of symptoms, the size of the cyst, and the surgical procedure used.
  
  
  RESULTS
  Neurological recovery was observed in all patients, and there was no recurrence. Poor outcomes were observed in patients with a long duration of symptoms (>1 year, P < .01) and large cyst size (>5 vertebrae, P < .05). The surgical procedure had no significant association with the postoperative neurological recovery. However, there was a significant difference in the degree of the mean postoperative kyphotic angle between the patients treated by total resection of the cyst (9.7 degrees) and those treated by closure of the dural defect without cyst resection through selective laminectomy (2.2 degrees) (P < .01).
  
  
  CONCLUSIONS
  There was no significant difference in postoperative neurological recovery between the 2 surgical procedures. However, closure of the dural defect without cyst resection was less invasive, preventing postoperative kyphotic deformity of the thoracolumbar spine.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Haruki
authors.initials: H
authors.lastname: Funao
authors.forename: Masaya
authors.initials: M
authors.lastname: Nakamura
authors.forename: Naobumi
authors.initials: N
authors.lastname: Hosogane
authors.forename: Kota
authors.initials: K
authors.lastname: Watanabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuji
authors.forename: Ken
authors.initials: K
authors.lastname: Ishii
authors.forename: Michihiro
authors.initials: M
authors.lastname: Kamata
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiba
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D000328:Adult; D016080:Arachnoid Cysts / Q000175:diagnosis* / Q000601:surgery*; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000379:methods*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D013118:Spinal Cord Diseases / Q000175:diagnosis* / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000601:surgery*; D016896:Treatment Outcome