ABSTRACT
Objective:To analyze the radiographic improvements after Halo-gravity traction in severe kyphoscoliosis patientswith type III spinal cord on preoperative apex MRI, and to assess the clinical outcomes and surgical safety of Halo-gravity traction in this cohort.Methods:A total of 47 severe thoracic kyphoscoliosis patients with type III spinal cord on preoperative apex MRI who underwent preoperative Halo-gravity traction followed by one-stage posterior spinal fusion from February 2019 to June 2021 in the Nanjing Drum Tower Hospital were retrospectively analyzed. There were 18 males and 29 females with an average age of 22.5±12.8 years (range, 9-60 years). The average duration of traction was 7.4±3.9 weeks (range, 4-16 weeks). Radiographic parameters were measured including the coronal Cobb angle, distance between C 7 plumb line and center sacral vertical line (C 7PL-CSVL), sagittalglobal kyphosis (GK) and sagittal vertical axis (SVA) atpre-traction, post-traction and post-operation, respectively. The traction correction rate was measured as "traction degree before traction-traction degree after traction)/traction degree before traction" and the surgical correction rate was represented as "traction degree before traction-postoperative degree)/ traction degree before traction". The Frankel scoring system was used for the evaluation of neurological status at pre-traction, post-traction and post-operation. Results:All of 47 patients underwent the Halo-gravity traction and posterior spinal correction surgery. The C 7PL-CSVL was 35.7±16.9 mm at initial visit. At post-operation, C 7PL-CSVL was improved to 22.0±13.7 mm ( t=13.75, P<0.001), and the improvement rate was 39.9%±15.5%. The GK was 110.9°±22.1° at initial visit, which was improved to 84.1°±19.9° ( t=8.84, P<0.001) after Halo-gravity traction with an average correction of 23.7%±8.9%. At post-operation, GK was improved to 65.3°±19.3° ( t=10.63, P<0.001), and the improvement rate were 40.1%±20.7%. The SVA was 43.8±19.5 mm at initial visit. At post-operation, SVA was improved to 21.1±14.9 mm ( t=10.32, P<0.001), and the improvement rate were 53.1%±27.0%. A total of 14 patients showed neurological deficits of lower limbs at pre-traction, of which 8 patients had significant neurological improvement after Halo gravity traction; 3 patients had significant neurological improvement after surgery, and the remaining 3 patients had no significant neurological improvement during treatment. No new neurological deficits were observed after Halo-gravity traction or surgery. Conclusion:For severe kyphoscoliosis patients with type III spinal cord on preoperative apex MRI, the Halo-gravity traction could effectively correct the deformity, improve neurological function, enhance the tolerance of spinal cord to surgery and reduce the risk of intraoperative iatrogenic neurological deficit.