MRI nomenclature for musculoskeletal infection.

The Society of Skeletal Radiology (SSR) Practice Guidelines and Technical Standards Committee identified musculoskeletal infection as a White Paper topic, and selected a Committee, tasked with developing a consensus on nomenclature for MRI of musculoskeletal infection outside the spine. The objective of the White Paper was to critically assess the literature and propose standardized terminology for imaging findings of infection on MRI, in order to improve both communication with clinical colleagues and patient care.A definition was proposed for each term; debate followed, and the committee reached consensus. Potential controversies were raised, with formulated recommendations. The committee arrived at consensus definitions for cellulitis, soft tissue abscess, and necrotizing infection, while discouraging the nonspecific term phlegmon. For bone infection, the term osteitis is not useful; the panel recommends using terms that describe the likelihood of osteomyelitis in cases where definitive signal changes are lacking. The work was presented virtually to SSR members, who had the opportunity for review and modification prior to submission for publication.

Preoperative cryoablation of a hypervascular bone metastasis: A case of effective devascularization before preoperative embolization.

Image-guided cryoablation has become a common approach for the palliative treatment of painful metastatic bone lesions, and indications for this procedure have expanded to include local control of bone metastases. We report a case in which cryoablation was performed on a large hypervascular renal cell carcinoma bone metastasis before surgical fixation of an impending fracture. In this case, cryoablation reduced the patient's pain but also appeared to result in devascularization of the tumor, thus obviating the need for preoperative embolization. This case raises the possibility that image-guided cryoablation may represent an alternative to preoperative embolization for vascular tumors while also serving a palliative function.

Isolated septic facet joints: an underdiagnosed distinct clinical entity.

OBJECTIVES: 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. METHODS: 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. RESULTS: Patients were predominantly male 38/62 (61%). The mean age was 56.7 years. 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. CONCLUSION: 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.

Update on spinal epidural abscess.

PURPOSE OF REVIEW: Spinal epidural abscess (SEA) is still a rare but potentially very morbid infection of the spine. In recent years, the incidence has risen sharply but the condition remains a medical conundrum wrought with unacceptably long diagnostic delays. The outcome depends on timely diagnosis and missed opportunities can be associated with catastrophic consequences. Management and outcomes have improved over the past decade. This review focuses on risk factors and markers that can aid in establishing the diagnosis, the radiological characteristics of SEA on MRI and their clinical implications, as well as the importance of establishing clear indications for surgical decompression. RECENT FINDINGS: This once exclusively surgically managed entity is increasingly treated conservatively with antimicrobial therapy. Patients diagnosed in a timely fashion, prior to cord involvement and the onset of neurologic deficits can safely be managed without decompressive surgery with targeted antimicrobial therapy. Patients with acute cord compression and gross neurologic deficits promptly undergo decompression. The greatest therapeutic dilemma remains the group with mild neurological deficits. As failure rates of delayed surgery approach 40%, recent research is focused on predictive models for failure of conservative SEA management. In addition, protocols are being implemented with some success, to shorten the diagnostic delay of SEA on initial presentation. SUMMARY: SEA is a potentially devastating condition that is frequently missed. Protocols are put in place to facilitate early evaluation of back pain in patients with red flags with appropriate cross-sectional imaging, namely contrast-enhanced MRI. Efforts for establishing clear-cut indications for surgical decompression of SEA are underway.

Infections of the Spine.

Pyogenic infections of the bony spinal column and the intervertebral discs are on a steady rise in an aging western population. Despite advanced medical imaging, this clinical entity of devastating consequences if missed, still presents a diagnostic conundrum and is plagued by an unacceptably long diagnostic delay. The aim of this article is to raise awareness of the heterogeneity of spinal infections paralleling the complex structure of the spinal column and neighboring soft tissues. Emphasis is placed on the clinical presentation and management of septic facet joints and psoas muscle abscesses associated with lumbar spondylodiscitis.

Radiologic Approach to Musculoskeletal Infections.

Imaging is often used to establish a diagnosis of musculoskeletal infections and evaluate the full extent and severity of disease. Imaging should always start with radiographs, which provide an important anatomic overview. MRI is the test of choice in most musculoskeletal infections because of its superior soft tissue contrast resolution and high sensitivity for pathologic edema. However, MRI is not always possible. Alternative imaging modalities including ultrasound scan, computed tomography, and radionuclide imaging may be used. This article reviews the individual imaging modalities and discusses how specific musculoskeletal infections should be approached from an imaging perspective.

Septic Arthritis of an Atlantoaxial Facet Joint with Normal Inflammatory Markers: Case Report and Literature Review.

BACKGROUND: Septic arthritis of the atlantoaxial facet joint is extremely rare. Contiguous spread to the median atlantoaxial joints with subsequent dens erosion can lead to atlantoaxial instability. Misleading normal inflammatory markers can result in delayed diagnosis and catastrophic consequences. CASE DESCRIPTION: A 56-year-old man presented with right-sided neck pain that had lasted for 2 days. He did not have fever or chills, and his serum C-reactive protein and erythrocyte sedimentation rate were normal. The patient was diagnosed with acute neck strain and treated conservatively. The pain continued for the next 3 weeks; cervical spine radiographs demonstrated normal findings with the exception of degenerative changes. The patient was treated with physical rehabilitation for the presumed neck strain and degenerative changes of the cervical vertebrae. Worsening neck pain and stiffness prompted a magnetic resonance imaging study obtained 5 weeks after the initial presentation, which showed an epidural collection with septic arthritis of the right facet and median atlantoaxial joints. Computed tomography demonstrated severe dens erosion. Surgical evacuation of the abscess and occipitocervical fusion were performed. Pathologic evaluation of tissue obtained during surgery demonstrated the presence of an infection, and Streptococcus anginosus grew from cultures. CONCLUSIONS: Infection must be considered in the differential diagnosis for neck pain when imaging findings are suggestive of an infectious process, even in an afebrile patient with normal C-reactive protein and erythrocyte sedimentation rate levels. Magnetic resonance imaging and computed tomography can play a critical role in such cases, potentially leading to a more timely diagnosis.