summary Spinal epidural abscess is a spinal infection caused by a collection of pus or inflammatory granulation tissue between the dura mater and surrounding adipose tissue Early diagnosis is critical and is made with contrast-enhanced MRI Treatment is usually prompt surgical decompression and long-term IV antibiotics Epidemiology Demographics usually seen in adults >60 y/o Anatomic location usually located dorsally in the thoracolumbar spine Risk factors IV drug abuse immunodeficiency malignancy HIV immunosuppressive medications recent spinal procedure Etiology Pathophysiology origin hematogenous spread ~50% spread from discitis ~33% pathogens Staph aureus is most common (50-65%) Gram-negative organisms, such as E. coli (18%) Pseudomonas in patients with IV drug use Neurologic deficits 33% of patients with an epidural abscess have been found to have neurologic symptoms 4-22% incidence of permanent paralysis can be caused by direct compression or infarction of blood flow to the spinal cord Associated conditions often associated with vertebral osteomyelitis and discitis (spondylodiscitis) present in ~18% of patients with spondylodiscitis Presentation Symptoms systemic illness is typically more profound than in patients with vertebral osteomyelitis fever is present in ~50% pain often severe and insidious in onset occurs in 87% Physical exam neurologic deficits present in ~33% may present as a radiculopathy or a myelopathy Labs WBC mean leukocyte count is 22,000 cells/mm³ elevated in ~42% ESR elevated in >90% of cases (mean 86.3%) CRP elevated in 90% of cases Imaging Radiographs usually normal CT poor sensitivity for detecting epidural abscess CT myelogram 90% sensitivity, but invasive MRI with gadolinium imaging modality of choice for the diagnosis of spinal epidural abscess shows the extent of the abscess, presence of vertebral osteomyelitis, and degree of neurologic compression gadolinium allows differentiation of pus from CSF a ring-enhancing lesion is pathognomonic for an abscess MRI of the entire spine should be performed to rule out skip epidural abscesses concomitant infection outside the spine delayed presentation (>7 days of symptoms) ESR >95 mm/hour Treatment Nonoperative bracing and IV antibiotics indications small abscess with minimal compression of neural elements and no neurologic deficits and patient capable of close clinical follow-up patients who are not candidates for surgery due to medical comorbidities outcomes historically, the presence of an epidural abscess was considered a surgical emergency recent trend toward nonoperative management, as new studies demonstrate that nonoperative treatment may be effective in patients without neurologic deficits medical treatment failure is associated with: neurologic deficits (strongest predictor of medical treatment failure) diabetes CRP >115 mg/L WBC >12 k/mL positive blood cultures >65 y/o MRSA Operative surgical decompression +/- spinal stabilization indications neurologic deficits present risk factors for failure of nonoperative management: older (>65 y/o), diabetics, new-onset neurologic deficits, and MRSA infection evidence of spinal cord compression on imaging studies persistent infection despite antibiotic therapy progressive deformity or gross spinal instability postoperative antibiotics 2-4 weeks if no bony involvement 6 weeks if bony involvement Techniques Decompressive laminectomy most common form of operative treatment indications abscess is located posteriorly and there is no contiguous spondylodiscitis avoid wide decompression and facetectomy, as these can result in spinal instability Anterior debridement and strut grafting indications abscess is located anteriorly anterior vertebral body and discs are involved (presence of spondylodiscitis) Prognosis Preoperative degree of neurologic deficit is the most important indicator of clinical outcome Mortality ~5% Early diagnosis is the most essential factor in preventing devastating complications