ment. There is no established consensus regarding the ideal treat- ment modality37,38). Nevertheless, the overall management princi- ples would be obvious that correct the deformity and instability, induce neurological recovery, allow early mobilization and return to work while incurring minimal complication. There are some major factors to consider when determining the optimal treat- ment; neurological status, spinal stability, degree of deformity, and associated injuries. There is still a controversy as to the indications for operative treatment and types of stabilization procedure for the thoraco- lumbar burst fracture. But, the unstable fracture frequently re- quires surgical correction. Progressive neurological deteriora- tion is generally considered an absolute indication for early surgery4,15). Other strong indications for surgical intervention include incomplete neurological deficit, more than 25° to 30° angle of kyphotic deformity, more than 50% loss of vertebral body height, more than 40% to 50% canal narrowing. The main goals of surgical treatment are to decompress the neural ele- ments for neurological recovery and to restore the spine stabili- ty with a correction of the deformity. Surgical treatment pro- vides immediate spinal stability and allows rapid mobilization. In addition, it also restores sagittal alignment, vertebral height and spinal canal dimension than cast or brace management more reliably33). Furthermore, it can also prevent complications of con- servative management such as prolonged recumbency, pressure sores, residual kyphosis, belated neurologic impairment12). Since Roy-Camille et al.28) used plates with pedicle screws for the fixation of thoracolumbar fracture in 1963, various tech- niques have been introduced, including anterior, posterior or combined (circumferential) fixation. Biomechanical data com- paring these techniques have been described in several litera- tures13,16,32). Posterior transpedicular screw fixation allows imme- diate and superior stabilization of the spinal column. Nowadays, posterior short segment pedicle screw fixation (that is, involving one vertebra above and one below the fractured level) has be- come popular for management of thoracolumbar fractures. Internal fixation with spinal fusion is a surgical treatment method that is generally accepted for patients with thoracolum- bar fracture. Achievement of solid fusion leads to a lower risk of implant failure, while fusion components restrict segmental motion and increase stress on the adjacent levels1,2,6,26,39). There- fore, there is a constant debate on the necessity and reliability of fusion techniques for the treatment of the thoracolumbar burst fracture with the posterior instrumentation. Some clinical stud- ies have demonstrated good treatment outcomes of the single instrumentation without fusion9,29,39). In the present study, we retrospectively reviewed the clinical and radiological outcomes of 46 patients with thoracolumbar burst fracture, who underwent posterior pedicle screw fixation. Based on the posterolateral fusion, we divided them into two groups; the non-fusion group and fusion group. Then, our clin- ical series of patients randomly underwent the posterior fixa- tion alone or were supplemented with posterolateral fusion. Posterior Fixation Alone in Thoracolumbar Fractures | JU Hwang, et al. The preoperative characteristics, postoperative clinical out- comes and changes of kyphotic angle were compared between the two groups. The purpose of the present study was to evalu- ate the necessity of posterolateral fusion in patients with thora- columbar burst fracture who were treated with the posterior pedicle screw fixation. MATERIALS AND METHODS We retrospectively examined 59 consecutive patients with thoracolumbar burst fracture who were surgically treated be- tween January 2007 to December 2009. Because 13 patients had no follow-up imaging after discharge, 46 patients were fi- nally enrolled in the present study. All our clinical series of pa- tients had a burst fractures from T12 to L3 level and underwent the posterior pedicle screw fixation. Based on the posterolateral fusion, our patients were divided into two groups; the non-fu- sion group and fusion group. The fusion groups was composed of 19 patients who underwent the posterior instrumentation with posterolateral fusion. But, there were 27 patients who re- ceived no fusion procedure. The indications for operative man- agement were kyphotic deformity more than 30° and/or anterior vertebral height loss more than 50% as well as the involvement of more than two spinal columns. Patients randomly underwent the posterior fixation alone or were supplemented with pos- terolateral fusion. The number of operating segments (short versus long) was determined based on the pattern of fracture, the severity of kyphotic deformity and surgeons’ preference. All the patients underwent a similar posterior pedicle screw fixation with no respect to the number of fixed levels (Fig. 1). Patients were placed in a prone position on a Wilson frame un- der general anesthesia. Pedicle screw fixation and reduction was performed under C-arm guidance. Some patients, who had more than 50% canal encroachment with/without progressive neurological deterioration, received laminectomy or another decompressive procedure. All patients underwent postural and instrumentation via screw-rod system reduction to achieve sat- isfactory reduction. Especially, monoaxial reduction screws (long lever-arm) were used and total laminectomy underwent in case of severe kyphotic deformity and/or canal encroach- ment. In the fusion group, simultaneous posterolateral fusion with bone graft was carried out after screw fixation (Fig. 2). The spine was exposed laterally to the tip of both transverse pro- cesses and it was cleaned from soft tissue and then decorticated to increase the recipient area with a high-speed burr. The bone graft materials, consisting of autologous local bone graft and/or synthetic bone substitutes, were placed in the decorticated area of the fixed segments. The local bone graft (LBG) was harvest- ed from the decompression site and morselized into small cor- ticocancellous pieces. Tricalcium phosphate or hydroxiapatite granule/strip type were used as bone substitutes solely or in com- bination with the LBG. From the postoperative day 2 or 3 on, our patients were recommended to use a custom-fitting thoracolum- 347