The influence of preoperative Halo-gravity traction on the selection of osteotomy grades in the treatment of severe kyphoscoliosis secondary to neurofibromatosis type Ⅰ

English Keywords:Neurofibromatosis  Scoliosis  Kyphosis  Halo-gravity traction  Osteotomy

English Abstract:

  【Abstract】 Objectives: To evaluate the effects of preoperative Halo-gravity (HGT) traction on the osteotomy grades selection plan in the treatment of severe kyphoscoliosis secondary to neurofibromatosis type Ⅰ(NF1). Methods: From January 2011 to December 2018, a consecutive cohort of 19 NF1 patients with severe kyphoscoliosis who underwent surgery in our institute were retrospectively reviewed, including 11 males and 8 females with an average age of 15.8±7.1(6-41) years old. According to the treatment methods, patients were divided into 2 groups: 13 patients in group A were treated with preoperative HGT followed by posterior surgery; 6 patients in group B underwent one-stage posterior surgery with spinal osteotomies. The osteotomy grades, operation data and perioperative complications were recorded. Radiographic parameters including the Cobb angle of coronal curve, coronal deformity angular ratio(c-DAR), global kyphosis(GK) and sagittal deformity angular ratio (s-DAR) were measured and compared before traction, after traction and immediately after surgery. Results: No significant difference was observed between the two groups in terms of the demographic data, pulmonary function and the preoperative radiographic parameters. For patients in group A, the average maximum traction weight of HGT was 13.0±2.1kg(9-16kg) and the traction duration was 9.9±3.8(6.5-19) weeks. Before traction, the coronal Cobb angle and sagittal Cobb angle was 109.9°±23.2° and 84.2°±16.2° respectively, and they decreased to 81.4°±21.0° and 68.0°±15.2° after traction. The coronal and sagittal correction rates of deformity were (26.3±9.1)% and (18.9±11.7)% respectively. The c-DAR and s-DAR was significantly decreased from 17.5±4.1 and 13.0±3.6 to 12.8±3.5 and 10.9±2.7, respectively. 8 patients(8/13, 61.5%) in group A needed not undergo three-column osteotomies after traction treatment, only Ponte osteotomies were performed, while all the 6 patients in group B underwent three-column osteotomies. After surgery, the coronal Cobb angle further improved to 60.8°±19.8° and GK decreased to 46.2°±16.1°, with a correction rates of (45.2±10.9)% and (45.5±15.7)% respectively. For patients in group B, the coronal Cobb angle and sagittal Cobb angle was 101.7°±14.5° and 75.5°±9.9° respectively, and they decreased to 60.8°±19.8° and 39.0°±5.0° after surgery. The coronal and sagittal correction rates of deformity were (49.9±10.8)% and (47.9±7.2)% respectively. There was no significant difference with respect to the deformity correction rates between both groups(P>0.05). The operation time was significantly shorter and the intraoperative blood loss was significantly less in group A than in group B(P<0.05). 1 patient in group A had transient brachial plexus palsy which resolved completely after reducing the traction weight. Each group had 1 patient occurring abnormal intraoperative monitoring during the osteotomies period. No neurological defects were observed postoperatively. Conclusions: For NF1 patients with severe kyphoscoliosis, preoperative Halo-gravity traction is an effective and safe strategy, which can improve spinal deformity to some extent. In addition, it could increase the safety of surgery through reducing the osteotomy grades, shortening the operation time, and reducing blood loss.