Addressing severe spinal deformities associated with neurofibromatosis type 1: Surgical strategies and outcomes.

Background: Surgical strategies for spinal deformities associated with neurofibromatosis type 1(NF-1) have been still controversial due to the wide variety of pathologies, particularly, for deformities with severe dystrophic changes in pediatric patients remained challenging with high complication and reoperation rates. The purpose of this study was to validate our surgical strategies by evaluating clinical and radiographical outcomes.

Methods: We retrospectively evaluated 22 cases who underwent correction surgeries for spinal deformities in our institute. The investigations included patient background, presence of dystrophic changes and paravertebral tumors, surgical procedure, number of surgeries, complications and reoperation, and radiographical parameters including Cobb angle and T1-S1 length.

Results: The mean age at the first surgery was 11.6 ± 5.5 years. The mean follows up period was 84.3 ± 50.2 months. Of the 22 cases, 4 cases had cervical kyphosis and 18 cases had deformity in thoracic and/or lumbar spine. Dystrophic changes of spine were observed in all 4 cases with cervical kyphosis and 15 cases with spinal deformity in thoracic and/or lumbar spine. All cases with cervical kyphosis underwent posteroanterior fusion following halo gravity traction preoperatively. The mean local kyphosis of cervical spine improved from 83.7 ± 5.9° to 16.9 ± 2.4° after surgery and 19.4 ± 2.5° at final follow up, and 2 cases required unplanned surgery due to pseudarthrosis. In cases of deformity in thoracic and/or lumbar spine, 11 cases underwent posteroanterior fusion, 4 cases underwent only posterior fusion, and 3 cases underwent conventional growing-rod, of which 4 cases underwent halo gravity traction before correction surgery. The mean Cobb angle of scoliosis in thoracic and/or lumbar spine improved from 73.2 ± 16.9° to 30.9 ± 15.8° after surgery and 29.5 ± 13.3° at final follow up, and that of T1-S1 growth increased from 338.3 ± 13.3 mm to 406.3 ± 8.9 mm at final follow up. Four cases required unplanned surgery due to pseudarthrosis (n = 2) or progression of deformity (n = 2).

Conclusion: The fundamental of surgical treatment for NF-1-related spinal deformity is extensive rigid spinal fusion by adequate bone grafting. Even if these surgeries are performed, in some cases additional surgery could be necessary due to progression of deformity.

Level Of Evidence: Level III, retrospective cohort study.