BACKGROUND The anatomy and biomechanics of the thoracolumbar spine place these segments at high risk of trauma injuries. Treatment options are either conservative or surgical, and there is a lack of consensus about the right indications. International scientific publications agree only on basic surgical principles: vertebral stability, deformity correction, protection of neurological structures and fast functional recovery. The most commonly used approach is the posterior approach, which allows the best management of most vertebral fracture patterns. The aim of this study was to compare clinical and radiological outcomes of monosegmental stabilisation with those of bisegmental stabilisation and fusion in the treatment of traumatic thoracolumbar spine fractures. METHODS This retrospective clinical and radiological study evaluated 48 consecutive patients treated with monosegmental (Group M; n=14) or bisegmental (Group B; n=34) posterior pedicular instrumentation for thoracolumbar fractures. Fractures were classified by the new AO Spine TLIC system. Average follow-up was 30 months. Clinical outcomes in both groups were statistically compared. Radiological outcomes were evaluated in terms of vertebral anterior body height restoration and correction of the kyphotic deformity. RESULTS Radiographical results showed no statistically significant difference between the two groups in vertebral body height restoration and correction of the kyphotic deformity. The mean postoperative somatic vertebral anterior body height in Group M was 25.8±4.52mm and in Group B it was 24.43±4.27mm. In Group M the mean postoperative kyphotic deformity was 11.10±5.71°, in Group B it was 9.09±4.93°. CONCLUSIONS The results of this study confirm the validity of short and very short instrumentation for the treatment of well-selected type A and B vertebral fractures. In C type fractures correct surgical indication must be evaluated on an individual basis.