Surgical treatment of spinal deformities associated with neurofibromatosis type 1. Report of 12 cases.

Abstract

In 10 to 50% of cases with neurofibromatosis, skeletal disorders are present, mainly as various deformities of the spine. These deformities can be divided into dystrophic and nondystrophic groups depending on the absence or presence of bone dystrophy. The nondystrophic curves are highly similar to those in idiopathic scoliosis, whereas the dystrophic curves are manifested early and, by progressing inexorably, may lead to neurological symptoms. In this article the authors report on a series of 12 patients (11 with dystrophic and one with nondystrophic deformities) who underwent surgical treatment. In the case with a nondystrophic curve, posterolateral instrumentation-assisted fusion was performed. A curvature correction of 70% was achieved in the frontal plane, and at the 2-year follow-up examination neither bone dysplasia nor pseudarthrosis was observed. In the cases with dystrophic curves, preoperative traction for 3 weeks was applied; anterior surgical release was then performed, as was two-stage posterior instrumentation-assisted fusion. In the cases of thoracic kyphoscoliosis in which this treatment protocol was performed, the mean scoliosis correction was 66%, whereas the mean decrease in kyphotic angle was 34.5 degrees. In the cases with thoracolumbar and lumbar curves, the mean correction in the frontal plane was 69.8 degrees, whereas the mean preoperative lumbar kyphosis of 42 degrees was corrected to a mean lordotic angle of 23 degrees. Postoperatively, no hook dislocation was detected. A neurological complication was observed in one case. The surgical treatment of dystrophic curves always included 360 degrees fusion and the use of a tibial corticocancellous graft, which must be placed on the concave side of the curve in the frontal plane, the graft thereby providing biomechanical support.