Comparison of efficacy of KumaFix posterior spinal screw / rod system and posterior U-shape screw / rod system for treatment of thoracolumbar vertebral body fractures

Abstract

Objective To compare the efficacy of KumaFix posterior spinal screw/rod system (KumaFix system) and posterior U-shape screw/rod system for treatment of thoracolumbar vertebral body fractures. Methods A total of 131 patients with thoracolumbar vertebral body fractures treated from January 20ll to July 2011 were prospectively analyzed. All patients showed thoracolumbar injury classification and severity score (TLICS) more than 5 points and spinal load-sharing classification (LSC) score of 4-6. The patients were assigned to two groups according to the coin toss method: group A (n=72, treated with reduction and fixation with KumaFix system in combination with transpedicular bone grafting of fractured vertebrae) and group B (n=59, submitted to posterior reduction and fixation with U-shaped screw/rod system in combination with transpedicular bone grafting of fractured vertebrae). In group A, there were 41 male and 31 female patients at age of (41.2±4.9)years (range, 20-53 years). In group B, there were 33 male and 26 female patients at age of(40.6±4.5)years (range, 21-51 years). The two groups were analyzed and compared in aspects of operation time, blood loss, anterior vertebral height ratio, middle vertebral height ratio, posterior vertebral height ratio, kyphosis angle, Oswestry disability index (ODI) and incidence of adjacent segment degeneration. Results All patients were followed up for mean 5.3 years (range, 5.1-5.8 years). Operation time and blood loss were (72.5±21.8)min and (320.6±90.0)ml in group A, less than (104.3±20.7)min and (421.0±84.5)ml in group B ( P<0.05). Both groups achieved obvious improvements in anterior vertebral height ratio, middle vertebral height ratio, posterior vertebral height ratio and kyphosis angle after operation(P<0.05). At the last follow-up, the middle vertebral height ratio was (92.0±2.8)% in group A, better than (84.1±5.1)% in group B (P<0.05). Both groups showed improvement in ODI after operation(P<0.05). At the last follow-up, ODI and incidence of adjacent segment degeneration were 11.9±7.1 and 0 in group A, decreased compared to 20.9±6.7 and 12% in group B (P<0.05). Conclusions For thoracolumbar vertebral body fractures, the KumaFix system has better reduction effect than U-shape screw/rod system. Meanwhile, the KumaFix system can avoid negative effect. Key words: Spinal fractures; Thoracic vertebrae; Lumbar vertebrae; KumaFix system