Rotatory Dislocation of the Spine in Dystrophic Kyphoscoliosis Secondary to Neurofibromatosis Type 1

Abstract

Aim of the study: Neurofibromatosis type 1 (NF-1) is associated with the development of scoliosis or kyphoscoliosis. The deformity is rapidly progressive in the presence of dystrophic changes producing bone erosion. Vertebral subluxation or dislocation can occur in children with highly dystrophic kyphoscoliosis and carries an increased risk of paralysis. There is no standardised treatment for this extreme deformity with very few patients currently reported in the literature. Methods: Retrospective review of a patient with NF-1 who developed a dystrophic upper thoracic kyphoscoliosis with segmental displacement of T2 on T3. Results: We report a patient with NF-1 who presented at 8.9 years with a progressive upper thoracic kyphoscoliosis. At 18.8 years, the deformity had deteriorated to scoliosis 65° and kyphosis 78° with fixed segmental rotatory dislocation at T2-T3. He underwent posterior cervico-thoracic fusion with concave pedicle screw/hook/rod instrumentation and iliac crest bone. Minimum correction was achieved due to curve rigidity and inability to reduce the T2/T3 displacement by halo-femoral traction. At 7 months, an elective posterior re-grafting procedure was performed followed by anterior fusion with rib strut grafts between T2-T6 through a midline sternotomy. The patient is now 3.5 years after anterior surgery and remains neurologically intact with stable residual deformity and computed tomographic evidence of circumferential fusion. He has no back pain and resumed non-contact physical activities. Conclusions: Patients with NF-1 can develop dystrophic kyphoscoliosis with segmental spinal subluxation/dislocation. Circumferential fusion is a technically challenging procedure which often requires a multi-disciplinary surgical team but produces satisfactory clinical outcome preventing paraplegia.