Preliminary Study of a New Growing Rod System in Immature Swine Model

Abstract

Growing rod techniques have been demonstrated to be a valuable treatment in early-onset scoliosis; however, repeated surgeries and general anesthesia cannot be avoided. This study included 12 immature swine that were randomly assigned to receive either a novel growing rod system (experimental group) or a traditional growing rod system (control group). Lengthening was undertaken at 4-week intervals, for a total observation period of 12 weeks. Radiography, computed tomography, and motion analysis of the spine were conducted to evaluate rod extension, growth and nonfusion of the spine, and fixation. One swine (control group) was excluded from the analysis because of a deep wound infection at 1 week after the initial operation. No complications were observed in the remaining 11 swine. In the experimental group, the average lengthening operation lasted 12.1 ± 3.1 minutes, and average incision length was 1.1 ± 0.2 cm; both values were significantly less compared with the control group (P < 0.001). No significant between-group differences in mean trunk length, body mass, or thickness of cephalad-instrumented or caudad-instrumented vertebrae and intervertebral disks were present before the initial operation or at the final assessment (12 weeks after operation; P > 0.05). Spinal growth and motion of instrumented spinal segments were conserved. The novel growing rod system is safe and effective in immature swine, preserving spine growth potential and involving less surgical trauma.