Systematic Review of Secondary Spinal Intradural Arachnoid Cysts in Adults Following Nontraumatic Nonaneurysmal Perimesencephalic Subarachnoid Hemorrhage

Introduction: Secondary spinal intradural arachnoid cysts (SSIACs) following nontraumatic nonaneurysmal perimesencephalic subarachnoid hemorrhage (PMSAH) are rare pathological entities. Etiologies of SSIACs include post-trauma, inflammatory processes, infections such as meningitis, central nervous system hemorrhage, and iatrogenic causes. SSIACs following nontraumatic nonaneurysmal PMSAH are particularly challenging to treat. Optimal management strategies remain unresolved due to the rarity, limited large case series, and lack of comprehensive statistical analyses. The objective in this study is to obtain a preliminary overview of SSIACs following nontraumatic nonaneurysmal PMSAH clinical trajectories and management and a case of SSIAC following nontraumatic nonaneurysmal PMSAH.

Methods: We conducted a literature review using the PubMed database for the past 30 years (1990-2024). Keywords included "Adult" and "Spinal intradural arachnoid cysts" or "Secondary spinal intradural arachnoid cysts." Exclusions were non-English publications, nonhuman studies, primary spinal arachnoid cysts and studies lacking case details. Data on patient demographics, etiologies, treatment modalities, and clinical outcomes were extracted.

Results: Our search yielded two relevant reports, supplemented by our case report, totaling three cases of SSIACs following nontraumatic nonaneurysmal PMSAH (one male, two females). All cysts were thoracic, with two extending to the cervical spine. Symptoms included pain, lower motor weakness, numbness, ataxia, and urinary dysfunction. All cases underwent cyst evacuation and fenestration; two had cysto-peritoneal shunts, and one had a cyst-subarachnoid bypass.

Conclusion : SSIACs following nontraumatic nonaneurysmal PMSAH often manifest as progressive myelopathy, with severe cord compression due to arachnoiditis and occupying cysts. Treatment is challenging with high recurrence risks. A combined surgical approach, including cyst evacuation, fenestration, cysto-peritoneal shunt placement, and cyst-subarachnoid bypass, offers a viable option. Further research is needed to develop more effective treatments and understand the underlying mechanisms of arachnoid cysts.