Analysis of the preoperative risk factors of intraspinal rib head dislocation in children with dystrophic scoliosis secondary to type 1 neurofibromatosis and the related factors that affecting the passive reduction of rib head

English Keywords:Neurofibromatosis  Dystrophic scoliosis  Rib head  Spinal canal  Risk factors

English Abstract:

  【Abstract】 Objectives: To explore the preoperative risks and the factors affecting the rib head passive reduction of rib head dislocation into spinal canal in children with dystrophic scoliosis secondary to type 1 neurofibromatosis(NF1-DS). Methods: From September 2006 to May 2020, 130 patients with NF1-DS were included in this study, and 34 patients were found with intraspinal dislocation of rib head. 20 patients received growing rods treatment and 14 patients received posterior spinal fusion. 7 patients underwent rib head resection and 27 patients underwent surgery directly without rib head resection. The factors that related to preoperative intraspinal rib proportion(IRP) included age, body mass index (BMI), apical vertebral rotation(AVR), apical vertebral translation(AVT), the angle of intraspinal rib, proportion of rib width, the main tho?鄄racic Cobb angle, trunk shift(TS), thoracic kyphosis(TK), lumbar lordosis(LL) and sagittal balance. Pearson cor?鄄relation analysis was used to screen out the relevant factors and preformed multivariable linear regression to determine the independent risk factors of the IRP. Pearson correlation analysis was used to screen out the factors that related to the correction rate of IRP, included the correction rate of AVR, AVT, the main tho?鄄racic Cobb angle, TS, TK, LL and sagittal balance. Results: The incidence of intraspinal rib in NF1-DS pa?鄄tients was 26.2% (34/130). The preoperative IRP was (32.9±17.2)% (5.5%-68.5%). Preoperative IRP was cor?鄄related with BMI, AVR, AVT, the main thoracic Cobb angle and TK (P<0.05), but it had no correlation with age, the angle of intraspinal rib, proportion of rib width, TS, LL and sagittal balance(P>0.05). Multiple linear regression analysis indicated that BMI and main thoracic Cobb angle were independent risk factors of the pre?鄄operative IRP(B=-4.733, P=0.040; B=0.470, P<0.001). AVR, AVT and TK were non-independent risk factors of the preoperative IRP(P>0.05). In the 27 patients without rib head resection, the IRP decreased from preop?鄄erative (32.6±16.3)% to postoperative (18.9±11.6)%(P<0.05) and the correction rate of IRP was(46.6±19.9)%. The correction rate of IRP was correlated with the correction rate of the main thoracic Cobb angle(r=0.443, P<0.009). The correction rate of IRP was not correlated with the correction rate AVR, AVT, TS, TK, LL and sagittal balance(P>0.05). Conclusions: The patients with worse preoperative nutritional status and severe spinal deformity were more serious in the degree of IRP. The correction rate of the main thoracic Cobb angle should be corrected as much as possible, so as to increase the passive reduction of the intraspinal rib head.