Impact of Surgical Timing on Neurological Outcomes for Spinal Arachnoid Cyst: A Single Institution Series

Objective: Spinal arachnoid cysts (SACs) are rare lesions that often present with back pain and myelopathy. There is a paucity of literature evaluating the impact of surgical timing on neurological outcomes for primary SAC management. To compare long-term neurological outcomes in patients who were managed differently and to understand natural progression of SAC. Methods: We conducted a retrospective analysis of adult patients treated for SAC at our in-stitution from 2010 to 2021, stratified into 3 groups (conservative management only, surgi-cal management, or conservative followed by surgical management). Study outcome mea-sures were neurological outcomes as measured by modified McCormick Neurologic Scale (MNS), postoperative complications, and cyst recurrence. Nonparametric analysis was performed to evaluate differences between groups for selected endpoints. Results: Thirty-six patients with SAC were identified. Eighteen patients were managed sur-gically. The remaining 18 patients were managed conservatively with outpatient serial imag-ing, 7 of whom (38. 9%) ultimately underwent surgical treatment due to neurological de-cline. Most common presenting symptoms included back pain (50.0%), extremity weak-ness (36.1%), and numbness/paresthesia (36.1%). Initial/preoperative (p = 0.017) and 1-year postoperative (p = 0.006) MNS were significantly different between the 3 groups, but not at 6 weeks or 6 months postoperatively (p > 0.05). Additionally, at 1 year, there was no difference in MNS between patients managed surgically and those managed conserva-tively but ultimately underwent surgery (p > 0.99). Conclusion: Delayed surgical intervention in minimally symptomatic patients does not seem to result in worse long-term neurofunctional outcomes. At 1 year, postoperative MNS were significantly higher in both surgical groups, when compared to the conservative group highlighting worsening clinical picture regardless of preoperative observational status.