An unusual cause of low back pain? A case report

STUDY DESIGN: Case report. OBJECTIVE: To highlight the evaluation of a patient with low back pain after an incidental radiographic finding clouded routine management. SUMMARY OF BACKGROUND DATA: Greenfield filters have been used for 20 years with good results. Complications have been seen and documented, but the natural history of filter placement in young patients is not fully appreciated. A prong from a Greenfield filter embedded within a vertebral body has been reported once as an incidental finding in a patient undergoing prophylactic monitoring for recurrence of tumor. METHODS: A 31-year-old woman had a pulmonary embolus after surgery for a benign adnexal mass. A bleeding complication occurred after systemic anticoagulation, and a vena caval filter was placed to limit the possibility of further emboli. The patient was referred to the orthopedic clinic 5 years later with low back pain and an unusual finding on computer tomographic scan: One prong of the filter was embedded within a vertebral body. RESULTS: A bone scan was obtained to evaluate the status of bone activity around the prong. Bone reaction was not evident. Conservative management of her low back pain was instituted, and after 2 years, the patient remains asymptomatic. CONCLUSION: The overall use of vena caval filters has produced favorable results, although numerous complications have been reported. All long-term sequelae have not been completely identified.