L5 Osteoid Osteoma Treated with Partial Laminectomy and Cement Augmentation.

Osteoid osteoma is a benign primary bone tumor of unknown etiology that occurs most commonly in males during adolescence and early adulthood. Osteoid osteoma affects the spine in 20% of cases, and may cause spinal deformity, stiffness, and pain that may sometimes be worst at night. We present a novel description of a partial laminectomy with cement augmentation after resection of an osteoid osteoma. A 22-year-old male with a past medical history of Hodgkin's lymphoma status post chemotherapy and radiation to the mediastinum, and right hip osteoblastoma treated with surgery and radiofrequency ablation presented with low back pain for five years with a recent onset of severe radicular symptoms. The pain was described as shooting and radiating laterally down the right leg to the mid-calf without bowel or bladder incontinence. He has a known right L5 laminar sclerotic lesion measuring 11 x 10 mm causing neuroforaminal narrowing and it kept increasing in size despite previous treatment with stereotactic radiosurgery and radiofrequency ablation. This lesion was metabolically active on positron emission tomography-computed tomography (PET-CT) imaging. His pain was worsening and was refractory to physical therapy, non-steroidal anti-inflammatory drugs (NSAIDs), aspirin, and radiation therapy. A right L5 partial laminectomy was performed to resect the abnormality in an en-bloc fashion. The lesion did not involve the inner cortex of the bone. Lamina reconstruction was achieved with bone cement augmentation for the preservation of vertebral column strength. Pathology was consistent with osteoid osteoma with marrow edema. Microscopic findings include bony trabeculae associated with prominent rimming and hypercellular fibroblastic stroma. No nuclear atypia, necrosis or appreciable mitotic activity was observed. The patient remains neurologically intact with significantly improved radicular symptoms and low back pain. Osteoid osteoma of the lamina may be resected using a partial laminectomy and cement augmentation done to preserve the integrity of the posterior ligamentous complex, prevent potential fracture of the pars interarticularis, and avoid the need for lumbar fusion in younger patients in whom this pathology is commonly found.