RESUMEN
The sacrum is a triangular shaped bone made up of five fused vertebral bodies. It is composed of bone, cartilage, marrow elements as well as notochord remnants and is a common site for both benign and malignant (primary and secondary) tumors. Familiarity with the imaging features and clinical presentations of sacral bone tumors could be helpful in narrowing the differential diagnosis. Magnetic resonance imaging and computed tomography are the preferred imaging modalities for evaluating sacral masses. This pictorial review will highlight imaging features of common sacral tumors with pathologic correlation. Additionally, this article will review some critical principles and helpful tips to successfully biopsy these lesions.
RESUMEN
PURPOSE: Percutaneous radio-frequency ablation is a minimally invasive treatment option for osteoid osteomas. The ablation process is straightforward in the more common locations like the femur/tibia. Surgery has historically been the gold standard, but is currently used in lesions, that may not be effectively and safely ablated, i.e. close to skin/nerve. Radio-frequency ablation can still be used in such cases along with additional techniques/strategies to protect the sensitive structures and hence improve the outcomes. The authors describe their experience with four challenging osteoid osteoma ablation cases. METHODS: We retrospectively reviewed radio-frequency ablations of four osteoid osteomas in rather atypical locations, the protective techniques/strategies employed, the adequacy and safety of the radio-frequency ablation with the use of these techniques. RESULTS: All patients had complete resolution of pain with no recurrence in the follow-up period. No complications were reported. CONCLUSION: RFA has been proven to be an effective and safe option for treatment of OOs in the common locations. It is generally recommended to have a 1 cm safety margin between the RF probe and any critical structures in the vicinity. However, with OOs in atypical locations this may not be always possible and hence additional techniques may be needed to ensure protection of the surrounding sensitive structures and also allow for effective ablation.
RESUMEN
PURPOSE: To describe the MRI findings of the "Stener-like" lesion of the knee and its distinction from simple medial collateral ligament (MCL) tear. A "Stener-like" lesion of the superficial medial collateral ligament is a tear involving the distal fibers, where the torn fibers become displaced superficial to the pes anserinus fibers, a displacement which can prevent healing. METHODS: Nine cases of Stener-like lesion were prospectively diagnosed on MRI. Retrospective, IRB-approved, HIPAA-compliant chart review was performed to determine correlation of surgical and MRI findings. Seven cases were surgically confirmed and are included in the series. RESULTS: MRI is useful in making the diagnosis of Stener-like lesions and prompting the surgeon to explore the distal MCL. Coronal MRI shows variable proximal retraction of the torn ligament. It has a lax contour and abuts the pes anserinus. The proximity of the torn ligament end to the pes can result in misdiagnosis of a partial tear. Axial images are useful to confirm position of the ligament superficial to the pes. All cases had associated tear of the deep MCL fibers, as well as sprains of the proximal superficial MCL. CONCLUSIONS: It is important to recognize the Stener-like lesion because this lesion is usually managed surgically, while most MCL tears are managed conservatively. The presence of injury to the proximal MCL is usually present, and may be a distractor from the distal injury. Care must be taken to include the distal attachment of the sMCL on coronal MRI images.
