What is a reasonable surgical procedure for spinal extradural arachnoid cysts: is cyst removal mandatory? Eight consecutive cases and a review of the literature

Abstract

Background: Spinal epidural arachnoid cysts (EAC) are rare and may present with myelopathy, which can be completely curable with surgery. The majority of investigators believe that the repairment of dural defect is important to treat EAC. However, the necessity of excising EACs remains controversial. The purpose of this study was to find a reasonable surgical technique for treatment of EACs after considering the clinical outcome, recurrence, and complications.

Methods: The data from 44 operations in the literature and eight cases from our own experience were analyzed. This data included the surgical method, patient characteristics, level and size of the EAC, global assessment of the clinical outcomes, and the incidence of recurrence.

Results: The recurrence rate was 2.0 % and 66.7 % in the patients who underwent repair of the dural defect and in those failed to repair of the dural defect, respectively (p = 0.007). The recurrence rate was 8.3 % and 3.6 % in patients who underwent complete EAC excision totally, and those who underwent EAC fenestration only, respectively (p = 0.590). The clinical outcome in patients with repaired dural defects was significantly better than that in patients with unrepaired dural defects (2.61 vs.1.67) (p = 0.027). The clinical outcome score was 2.42 and 2.68 in patients who underwent complete EAC excision and those who underwent EAC fenestration only, respectively (p = 0.158). The mean EAC length was 5.04 vertebral body levels (range, 2-13). Six of the 51 patients (11.7 %) had multiple EACs.

Conclusions: Total excision of EACs may have little benefit in terms of cyst recurrence and clinical outcome. The procedure for EAC resection carries a risk of complications such as kyphosis. If EAC resection is performed, we suggest that a tailored short-level laminotomy be used to allow for the repair of dural defects. Particularly in patients with small EAC, a partial hemilaminectomy with dural defect repair may be a possible method to reduce complications.