Double rib penetration of the spinal canal in a patient with neurofibromatosis

Background: Rib head penetration into the spinal canal in patients with severe kyphoscoliosis secondary to neurofibromatosis type-1 (NF-1) is extremely rare. Double rib head penetration has only been reported once earlier. Methods: We are reporting on an adolescent male with NF-1 and severe thoracic kyphoscoliosis with adjacent double rib head penetration into the spinal canal without neurological deficits. Only one was recognized on the initial radiographic imaging. Results: A 14-year-old with NF-1 and 74 degrees left thoracic scoliosis and 75 degrees kyphosis was treated at our institution. Preoperative computed tomography (CT) demonstrated protrusion of the left T6 rib head into the spinal canal on the convexity of the curve, compressing the spinal cord. Staged surgical procedures for resection of the rib head and correction of the spinal deformity were planned. After presumed successful resection of the penetrated rib head, a postoperative CT revealed the presence of a second adjacent left T7 rib head in the spinal canal. This was not initially recognized owing to the severe deformity and image obliquity of the CT gantry. Another procedure was performed to remove this rib head. He was then placed in halo traction until anterior and posterior spinal fusion and segmental spinal instrumentation were performed. He achieved good deformity correction and had no neurological deficits throughout his treatment. Conclusions: Rib head protrusion into the spinal canal can occur with spine deformity in NF-1. If present, the imaging should be carefully reviewed for the possibility of an adjacent rib head penetration that may have been obscured by the limitations of CT in the context of a dysplastic spinal deformity. Level of Evidence: Level V. Case study.