A Classification System for Spinal Cord Compression and its Association With Neurological Deficit in Spinal Epidural Abscess

Study Design: This was a retrospective case-control study. Objective: We aim to describe a novel 5-point grading system to determine the degree and severity of spinal cord compression secondary to a spinal epidural abscess (SEA). Secondarily, we aim to correlate the degree of compression with clinical presentation and outcomes. Summary of Background Data: Mechanical compression plays an important role in the pathophysiology of neurological dysfunction in SEA. Unfortunately, no standardized classification system for describing the degree of spinal cord compression exists. The lack of a validated grading system makes it challenging to study and consistently report the relationship between cord compression and clinical presentation/outcomes in SEA. Materials and Methods: Patients 18 years and older admitted to our hospital system with a diagnosis of SEA located above the conus medullaris between 1993 and 2016 were included. Using pretreatment axial magnetic resonance images, we developed a 5-point classification scale to determine the degree of spinal cord compression. After assigning a compression grade to each abscess, we investigated the relationship between the degree of compression and presenting neurological symptoms. Furthermore, we assessed the association between compression grade and clinical outcomes. Results: Three hundred thirty-nine patients were included in the study. Patients with high-grade cord compression (grades 4 and 5) were significantly more likely to present with pretreatment motor deficit, sensory changes, and bowel/bladder incontinence. With respect to clinical outcomes, increasing degree of compression was not associated with failure of nonoperative management, residual motor deficit, or 90-day mortality. Conclusions: We report a novel grading system for spinal cord compression in SEA with 5 progressively increasing grades of compression. High-grade abscesses with cord compression were significantly associated with neurological deficit at presentation but not with poor outcomes. We hope that this classification system will allow for greater consistency in reporting the association between cord compression and neurological deficit in SEA.