Surgical treatment of scoliosis in neurofibromatosis type I: A retrospective study on posterior-only correction with third-generation instrumentation

Abstract

Background: Scoliosis is the most common orthopedic complication of neurofibromatosis type I. Scoliosis can be occurred with two patterns: dystrophic or idiopathic-like. In adolescence, in consideration of bone dystrophy, osteopenia, and often associated hyperkyphosis, most of the authors recommend an anterior-posterior approach. According to other authors, modern instrumentations could be sufficient to sustain a solid posterior arthrodesis.

Materials and methods: Ten patients were diagnosed with scoliosis in neurofibromatosis type I aged between 8 and 25 years, Cobb angle of the thoracic curve >45°, and minimum follow-up (FU) of 1 year and treated with posterior-only approach with third-generation high-density instrumentations. Radiographic measurements were performed on the coronal and sagittal planes. Nonparametric tests (Friedman test and Wilcoxon test) were applied to evaluate the reducibility of the preoperative curve (T0), the postoperative surgical correction (T1), and its maintenance on FU.

Results: Statistics showed results compared to those evaluated in the literature with a combined approach regarding surgical correction and its maintenance on FU. On T1, a median correction of 53.5% of the scoliotic curve and of 33.7% of the thoracic hyperkyphosis was observed. On FU, the correction was maintained. A global improvement in balance was appreciated. The curves, despite rigid, showed a relative reducibility to bending tests and traction. No significant complications occurred.

Conclusions: The posterior-only approach produces a satisfactory correction of the dystrophic neurofibromatosis scoliosis if associated with the use of high-density third-generation instrumentations. We are confident in recommending posterior-only approach in dystrophic neurofibromatosis scoliosis with coronal curves till 110° and coexisting thoracic kyphosis till 80°.

Keywords: Hooks; hybrid instrumentations; pedicle screws; posterior approach; sublaminar bands.

Figure 1

Bar chart on the frequency of vertebral pedicles

Figure 2

Rib dislocation with dislocation of the head of the rib in the vertebral canal on computed tomography image. (a) Axial view; (b) coronal view; (c) sagittal view

Figure 3

Patient 1 (female, 14 years old). X-ray examinations on coronal plane: (a) before surgery (T0); (b) immediate postoperative time (T1); (c) 4-year follow-up

Figure 4

Patient 1 (female, 14 years old). X-ray examinations on sagittal plane: (a) before surgery (T0); (b) immediate postoperative time (T1); (c) 4-year follow-up