Epidural abscess associated with pyogenic spondylodiscitis of the lumbar spine; evaluation of a new MRI staging classification and imaging findings as indicators of surgical management: a retrospective study of 37 patients.

ABSTRACT

INTRODUCTION: The aim of this study was to review the patients with lumbar epidural abscess in terms of neurological morbidity, therapeutic outcome, and prognosis, while assessing the usefulness of a new MRI staging classification and specific imaging findings as indicators for surgical management. MATERIALS AND METHODS: We reviewed 37 patients who sustained epidural abscess associated with pyogenic spondylodiscitis of the lumbar spine. Ten patients were treated conservatively, while 27 required urgent or elective surgical drainage. We studied patients with respect to symptomatology, Frankel-American Spinal Injury Association (ASIA) scale evaluation and a new proposed system of MRI staging of pyogenic spondylodiscitis (stages I­V). RESULTS: Of the 37 patients with stage IV and V MRI lesions, 13 (35%) had septicemia and 8 (22%) presented with Frankel-ASIA scale C-D neurological status. All cases with ringlike enhancement on gadolinium-enhanced MRI in the epidural abscess lesions were treated surgically. Progression of local kyphosis and loss of intervertebral disk height were significantly prevented in the surgical group (P < 0.05). Improvements of neurological status and laboratory data were better in the surgical group than the conservative group (P < 0.05), with significantly short hospital stay (P < 0.05). DISCUSSION: Epidural abscess associated with pyogenic spondylodiscitis presents with various neurological symptoms. In addition to assessment of progression by clinical symptomatology, modified neurological Frankel-ASIA scaling and the currently proposed MRI staging regimen may help to consider the timing of surgical intervention. In the acute, subacute or acute-on-chronic phase and the ringlike enhancement pattern of epidural abscess on gadolinium-enhanced MRI may be an indicator for surgery.