Pamidronate “zebra lines”: A treatment timeline

Abstract

Osteogenesis imperfecta is a hereditary bone dysplasia characterized by bone fragility, deformity, and short stature. Treatment focuses on preventing bone fractures and symptom relief. Pamidronate, a second-generation bisphosphonate drug that minimizes bone loss, is the chosen treatment in osteogenesis imperfecta. Radiologically, each cycle of pamidronate treatment is depicted as a line of sclerosed nondecalcified cartilage at the metaphysis, termed a pamidronate line. In this case report, we demonstrate that a treatment timeline can be visualized on plain radiographs as the number and spacing of pamidronate lines reflects the number and timing of treatment cycles. The educational value of this is to reassure physicians of the benign nature of “zebra lines,” to demonstrate that the pamidronate lines migrate and fade with bone growth, and alert physicians that the lack of expected pamidronate lines during treatment may reflect a change in the patient's condition that reduces the effectiveness of bisphosphonate infusions.

Whole-body MRI in the diagnosis of paediatric CNO/CRMO

“…Bilateral, symmetric metaphyseal high signal bands after the first course of bisphosphonate treatment, have been noted anecdotally (but not reported) and these may mimic disease relapse, particularly after the first course of bisphosphonate therapy (Figure 6a). This is in contrast to reports of low signal (sclerotic) lines on MRI (Figure 6b), equivalent to the radiographic "zebra-line" appearance which affect mainly the distal femora and proximal tibiae and fibulae (Figure 6c) (38)(39)(40).…”

Radiologic zebra line sign in a patient with Langerhans cell histiocytosis on bisphosphonate therapy

“…Bisphosphonates reduce the activity of osteoclasts by inhibiting their recruitment, thereby resulting in the uncoupling of bone remodeling. The zebra line sign refers to the line of cartilage calcification persisting from the metaphysis into the diaphysis [1,2]. This radiologic finding reflects the administration of bisphosphonate [3].…”