Study design: A retrospective study.
Objective: Aim of the study was to investigate morphological differences in the vertebrae of scoliosis secondary to neurofibromatosis type 1 (NF1-S) with and without paraspinal neurofibromas and to identify the relationship between paraspinal neurofibromas and vertebral deformity.
Summary of background data: Scoliosis is the most common orthopedic manifestation of NF1. Erosion or infiltration of the bone by localized neurofibromas was suggested as one of the primary etiology for the vertebral deformity.
Methods: One hundred fourteen patients with NF1-S were classified into spinal tumor (ST) group and nontumor (NT) group with respect to the presence of paraspinal neurofibromas. The curve pattern, curve magnitude, the shape and location of paraspinal neurofibromas, and various kinds of morphological changes of vertebrae were evaluated by complete radiographs were compared between the two groups to determine whether the presence of paraspinal neurofibromas could be associated with a more severe vertebral deformity.
Results: The ST and NT groups included 54 patients (age, 16.8 ± 5.5 years) and 60 patients (age, 17.3 ± 4.2 years), respectively. The Cobb angles of the main curve were 72.3° ± 20.6° and 65.4° ± 19.4° for the ST and NT groups, respectively. No significant differences were observed between the two groups in age, sex ratio, and Cobb angle. There were significant differences between the ST and NT groups in apical vertebral rotation (36.8° ± 7.2° vs. 27.5° ± 6.8°; P < 0.001) and the prevalence of rotatory subluxation (66.1% vs. 35.0%; P = 0.04). Most of the paraspinal neurofibromas (70.4%) developed within the apical region, with the majority (29/38) located on the concave side.
Conclusion: The NF1-S patients with paraspinal neurofibromas had significantly higher prevalence of morphological changes of vertebrae. The paraspinal neurofibromas, most of which were located on the concave side of the apical region, could be associated with more severe vertebral deformities.
Level of evidence: 3.