Atlantoaxial dislocation associated with type-1 neurofibromatosis: case report and review of the literature.

Background Neurofibromatosis type 1 (NF-1) is an autosomal dominant genetic condition in which spinal deformities are commonly involved. However, atlantoaxial dislocation in NF-1 is extremely rare. A review of the English literature has identified only 10 cases in 8 reports. We report a rare case involving NF-1 associated with severe atlantoaxial dislocation. Case Description A 22-year-old woman with NF-1 presented with progressive numbness in her left upper and lower extremities and gait difficulty for 2 months. She was treated with skull traction and partial reduction was achieved. Initial surgical strategy was posterior fusion using a screw-rod-wire construct, but significant bleeding was encountered during the surgery. To shorten the procedure time, a single sublaminar wire of the atlas was tied to the spinous process of the axis to accomplish the reduction and fixation. C1-C2 fusion was performed using iliac crest autograft. The patient had significant improvement of neurologic deficit after surgery. Due to relatively poor fixation provided by the wire, she was requested to rest in bed for the first 3 months and to wear a cervical orthosis for the next 3 months. Solid bony fusion was confirmed by radiologic examination at 18-month follow-up. Conclusions Atlantoaxial dislocation is a rare complication in NF-1 patients. Surgical reduction combined with fusion is essential for a good outcome. Spine surgeons should also be knowledgeable about the possibility of significant hemorrhage before surgery.