| Study design. A retrospective clinical study was performed.Objective. To determine the clinical, radiologic, and functional status of patients who underwent pedicle-screw fixation of thoracolumbar fractures, to compare the results of pedicle-screw fixation with and without fusion and to evaluate the effect of three types of pedicle-screw fixators(Dick internal fixator, Steffee variable screw placement system,and atlas fixation systerm).Methods. Sixty four patients with unstable thoracolumbar fractures were included in the study. The inclusion criteria was the presence of fractures through the T11-L4 vertebrae with or without neurologic compromise. Multi-segment fractures were excluded from the study. Part one: The patients were randomized into two groups. Group 1 patients were treated using pedicle-screw fixation with fusion(n = 23), and Group 2 patients were treated using pedicle-screw fixation without fusion(n = 41). Part two: The patients were into three groups. Group 1 patients were treated using Dick internal fixator (n = 11), Group 2 using Steffee variable screw placement system (n = 24), and Group 3 using atlas fixation systerm (AF) (n =18). All patients were evaluated clinically, radiographically, and functionally for a minimum of 1 years (mean 40 months). Clinical (Frankel/ASIA grade and Denis' pain and word scales) and radiologic (local kyphosis, percentage of anterior boby height compression) outcomes were analyzed.Results. Before surgey, vertebral kyphosis of all cases averaged 21.6° improved to 6.4° with reduction, and reached 12.2?at final follow -up. percentage of anterior boby height compression initially averaged 48.5% but was reduced to 15.8% with surgey and 24.7% at final follow-up.Both the kyphosis angle and boby height compression were improved after operation, but were losed in some degrees. The patients with incomplete spinal cord injury showed significant functional improvement.The two groups (with grafting and without grafting) were similar in age,follow-up period, and severity of the deformity and fracture. The postoperative and follow-up kyphosis angle, percentage of anterior boby height compression,and average correction loss in kyphosis angle and vertebral height in both groups were not significantly different. In grafting group, 83% of patients had little or no pain (P1P2) and 52% of patients had returned previous work (W1W2). In no grafting group, 76% of patients was rated P1P2 and 46% of patients was rated WlW2.The number of patients with serious pain in no grafting group was larger than grafting group, but there was no significant difference.Among the sixty four patients, Dick internal fixator, Steffee variable screw placement system,and atlas fixation systerm were used in 11, 18, and 24 cases respectively. In the dick group, the kyphosis angle was improved initially by 12.9°, and this was lost by 6.9° at follow-up. In the Steffee group, the kyphosis angle was improved initially by 11.5°, which was lost by 6.7° at follow-up. In the AF group, the kyphosis angle was improved initially by 19.9°, which was lost by 4.6?at follow-up. The correction loss of kyphosis angle in the AF group was smaller than that in the dick group and in the steffee group. The boby height loss were no significantly different in both groups.Conclusions. The pedicle screw instrumentation is one of effective devices for the treatment of thoracolumbar fracrures.but there are certain degree loss of the rate of compressed vertebral body height and correction loss in kyphosis angle at follw-up. Although pedicle-screw fixation by additional posterior grafting adds spine stability, it cannot prevent correction loss in kyphosis angle. There was no significant difference of correction loss in kyphosis angle and body height loss in the grafting group and in the no grafting group. According reduction degree and correction loss at follow-up, AF system is better than Dick internal fixator and Steffee variable screw placement system. |
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