J Korean Neurosurg Soc 52 | October 2012 A B C Fig. 1. A 48-year-old female was sustained an injury due to a motor vehicle. She was diagnosed with burst fracture of L1 and underwent a posterior short segment screw fixation including the index level (that is, the level of the burst fracture). A : The preoperative lateral view and CT scan show 17.9° kyphotic angle and 51% canal encroachment, respectively. B : The immediate postoperative lateral view shows that kyphotic angle was de- creased to 13.6°. C : At a 1-year follow-up, the lateral view shows 18.1° kyphotic angle. A B C Fig. 2. A 42-year-old male fell backwards from height of 3 meters. He was diagnosed with burst fracture of L2 and underwent total laminectomy with posterior short segment screw fixation involving the index level. Instrumentations were supplemented with posterolateral fusion. A : The preoperative lateral view and CT scan show 10.1° kyphotic angle and 62% canal encroachment, respectively. B : The immediate postoperative lateral view shows 12.3° lordotic angle and AP view reveals that bone graft materials were placed in the transverse process of fixed segments. C : At a 1-year follow-up, the lateral view shows 6.2° lordotic angle and the AP view demonstrates that bone grafts were partially absorbed (progression of bone fusion). Table 1. Demographic data of the patients No. of cases Male Female Fracture Level T12 L1 L2 L3 Fixed Level Short Long Mean age (range)* Mean F/U (range)† *Units : years, †Units : months Non-fusion group 27 18 9 9 (33.3%) 12 (44.4%) 4 (14.9%) 2 (7.4%) 15 12 49.93±11.70 (26-71) 16.07±11.45 (6-47) bosacral orthosis when sitting, standing or ambulating for three months postoperatively. Patients were assessed with plain X-ray films on standing an- tero-posterior and lateral views. A radiographic follow-up was done at immediately after surgery, 3, 6 months, and 1 year after surgery. Parameters were measured by Cobb technique; the ky- phosis on a lateral X-ray view from the superior endplate of the vertebral body one level above the injured vertebra body to the inferior endplate of the vertebral body one level below14). Clini- cal outcomes were evaluated using modified Mcnab criteria at a final follow-up. 6 13 49.11±19.56 (22-77) 14.63±9.44 (3-30) Fusion group RESULTS 19 11 The distribution of age, sex, and level 8 of fracture were similar between the 6 (31.6%) two groups (Table 1). The non-fusion 9 (47.4%) group included 27 patients (18 males 3 (15.8%) and 9 females), the fusion group 19 pa- 1 (5.3%) tients (11 males and 8 females), with no significant difference between the two groups in terms of male/female ratio (p=0.544, chi-square test). The mean age of patients was 49.93±11.70 years (range : 26-71) in the non-fusion group and 49.11±19.56 years (range : 22-77) in the fusion group (p=0.871, Welch’s t- test). The fracture levels at T12 was 9 cases; L1, 12 cases; L2, 4 cases, and L3, 2 cases in the non-fusion group. The fusion group had T12, 6 cases; L1, 9 cases, L2, 3 cases, and L3, only 1 case (p=0.802, Fisher’s exact test). The number of fixed levels in terms of short versus long was comparable in both groups (p=0.108, chi-square test). In the non-fusion group, 15 patients underwent short segment fixation while long segment fixation was performed in 12 patients. Whereas in the fusion group, these numbers were 6 and 13, respectively. The average follow- up period was also similar in both groups, 16.07±11.45 months 348