A novel subtype classification and corresponding surgical strategies for spinal dural cysts-a report of 104 cases.

Abstract

The nomenclature, classification, and surgical approaches for spinal dural cysts (SDCs) remain a subject of controversy. The present study proposes a novel subtype classification system and corresponding surgical strategies, with the aim of enhancing comprehension of this entity and standardizing surgical treatment. A retrospective review. A total of 104 patients with SDCs underwent novel subtype classification and corresponding surgical strategies from January 2015 to December 2021. Fifty-four patients who underwent conventional surgery from January 2012 to December 2014 as the control group for preliminary validation. The outcomes are categorized into 4 levels: excellent, good, unchanged, and deteriorated, based on neurological improvement and pain relief. Grades of excellent and good were identified as improvements. Follow-up magnetic resonance imaging and complications were also evaluated. Based on the shared pathogenic factor of dural defects, the dural-associated cysts in the spinal canal are uniformly referred to as SDCs. They are further classified into Type 1 (no nerve roots) and Type 2 (containing nerve roots), with 4 additional subtypes based on the shape of the leak and the flow of leakage. The fissure-shaped leak of Type 1a SDCs is directly sutured, whereas the aperture-shaped leak of Type 1b is repaired using a patch. Low-flow leakage of Type 2a is directly sealed using a combination of adipose tissue and fibrin glue, whereas high-flow Type 2b necessitates suturing at the end of the leak to attenuate cerebrospinal fluid flow prior to sealing. The follow-up period averaged 23.8 months. Excellent or good outcomes were achieved in 100%, 88.9%, 100%, and 97.3% for the 4 subtypes respectively. The overall improvement rate of SDCs was 97.1%, which was significantly higher than that of the conventional surgery group (85.2%, p=.008). MRI follow-up showed a significant reduction in cyst size of 100%, 100%, 97.8%, and 97.3% for the 4 subtypes, respectively. The primary complications included pseudomeningocele in 4 cases (3.8%) and delayed wound healing in 5 cases (4.8%). The complication rate was also significantly lower than that of the control group (8.7% vs 24.1%, p=.008). Subtyping SDCs based on the variation of leaks and leakage can enable more targeted surgical strategies, which are helpful for improving treatment effectiveness and reducing complications.