Percutaneous Pedicle Screw Fixation in Thoracolumbar Fractures: Comparison of Results According to Implant Removal Time

BACKGROUND: The purpose of this study was to determine whether restoration of range of motion (ROM) could be achieved by implant removal after natural bone healing and consolidation of fractured vertebrae and examine whether early removal of the implant could maximize restoration of ROM. METHODS: This study included 30 cases of thoracolumbar fractures without neurological deficit requiring surgery (nine cases of flexion-distraction injuries and 21 cases of burst fractures). Percutaneous pedicle screw fixation (PPSF) was performed at the fractured vertebrae and one level above and one level below the fracture level. Pedicle screws were removed at an average of 12 months after surgery upon healing of fractured vertebrae. The following radiological and clinical findings were evaluated: restoration of anterior vertebral height ratio (AVHR), Cobb angle (CA), ROM, and complications. Sixteen patients who were checked for ROM were divided into two groups based on the time of implant removal: nine patients within 12 months and seven patients after 12 months. Restoration of vertebral height loss and ROM were compared between the two groups. RESULTS: At the final follow-up, significant pain relief and restoration of AVHR and CA were achieved in patients who underwent PPSF. Patients who had implant removed within 12 months after surgery had better ROM recovery than those who had implant removed after 12 months postoperatively. There were no significant differences in AVHR and CA between the two groups. CONCLUSIONS: PPSF followed by implant removal after healing of fractured body appears to be effective in achieving restoration of ROM. In our study, early removal of implant within 12 months after surgery was associated with better achievement of ROM than removal after 12 months. In addition, there were no significant differences in restoration of vertebral height between the two groups.