The Challenge of Treating Syringomyelia Associated with Extensive Arachnoiditis

Background/Objectives: Extensive arachnoiditis associated with syringomyelia is a complex and multifactorial disease. This narrative review aims to synthesize current evidence on the terminology, pathogenesis, diagnostic evaluation, conservative and surgical management, and experimental approaches to arachnoiditis-related syringomyelia, with particular emphasis on the factors that limit durable treatment in extensive disease. Methods: PubMed was searched for English-language publications from January 2016 through August 2026 using the primary search terms "syringomyelia AND arachnoiditis," supplemented by targeted searches for diagnostic, surgical, and experimental studies. Fifty-seven publications were included in the narrative synthesis. Results: Focal arachnoid pathology is generally more amenable to surgical reconstruction, whereas extensive multilevel arachnoiditis is associated with greater treatment complexity, recurrence, and reintervention. No single surgical strategy provides consistently durable control across all patterns of extensive disease, and bypass or diversion procedures may be required when direct restoration of the subarachnoid space is not feasible. Experimental studies further implicate cerebrospinal fluid obstruction, spinal cord tethering, altered intramedullary fluid handling, and persistent glial or fibrotic scarring in syrinx formation and treatment failure. Conclusions: The success of treatment for extensive arachnoiditis with syringomyelia depends on the extent of subarachnoid space involvement, particularly the number of spinal segments involved. Available surgical strategies remain limited by recurrent fibrosis, retethering, symptom recurrence, and treatment failure over time. Better treatment modalities are needed.