Isolated septic facet joints: an underdiagnosed distinct clinical entity

Abstract

We review a series of isolated septic facet joints (ISFJ) that present as a distinct clinical entity compared with spondylodiscitis. We aim to raise awareness that septic facet joints are not a rare entity in the era of modern imaging. We reviewed 353 patients with confirmed spine infections from 2008 to 2017. Of the 353 cases, there were 152 septic facet joints based on MR imaging. Sixty-two presented as ISFJ without evidence of spondylodiscitis and were reviewed. Patients were predominantly male 38/62 (61%). The mean age was 56.7years. Onset of back pain was more acute compared with spondylodiscitis and usually unilateral. The distribution was as follows: 6 cervical, 12 thoracic, and 44 lumbar facets. The majority of ISFJ, 53/62 (85%), were associated with an epidural abscess (EDA) 53/62. The cervical and thoracic EDA required surgical decompression more frequently than lumbar; 100%, 75%, and 53% respectively. Pathogen was identified in 59/62 (95%) cases. Most cases were associated with bacteremia 50/62 (81%). Seven ISFJ were introduced iatrogenically. All iatrogenic ISFJ required surgical decompression. Septic facet joints are not rare, but frequently overlooked as the origin of an epidural abscess. The majority of cases are hematogenously seeded and associated with bacteremia. Surgical decompression is frequently required secondary to the high incidence of associated epidural abscess. Iatrogenic septic facet joints are rare but associated with significant morbidity. From a clinical standpoint, it is helpful to delineate the origin of EDA as either secondary to spondylodiscitis or SFJ.