Limitations of dorsal transpedicular stabilization in unstable fractures of the lower thoracic and lumbar spine: an analysis of 133 patients

The optimal treatment of thoracic and lumbar fractures remains controversial. While many authors recommend dorsal instrumentation with an internal fixator, others favour an anterior approach. To evaluate the posterior approach and to identify conditions under which an anterior approach should be preferred, 133 patients with unstable thoracic and lumbar fractures of the spine who underwent dorsal instrumentation with an internal fixator were analyzed. Clinical data were recorded prospectively with respect to fracture type, neurological findings, operative complications, spinal deformation correction, and long-term outcome. All fractures were located between the 7(th) thoracic and the 5(th) lumbar vertebrae and were considered to be unstable with respect to the three column model. Seventy-six patients (57%) received surgery within the first seven days after the trauma. Postoperatively, 98% of patients with a radicular lesion or an incomplete transverse syndrome (47 patients, 35%) improved. Stable fracture consolidation after fixator removal was obtained in 98% (130 of 133 patients). The preoperative kyphosis angle decreased from an average of 10.1degrees to 7.4degrees at the three year follow up. Major operative complications consisted of two isolated nerve root lesions (1.5%), two deep wound infections with need of fixator removal (1.5%), and mallocation of two pedicle screws with need for another procedure in two patients (1.5%). Three patients (2%) suffered from insufficient bony fusion with increase of kyphotic deformation and required subsequent anterior stabilization. These three patients presented with an initial kyphosis or wedge angle of 20degrees or higher. In conclusion, dorsal stabilization with the internal fixator is a safe and reliable treatment for unstable fractures of the lower thoracic and lumbar spine. The authors recommend this procedure because of its low-invasiveness in conjunction with satisfactory reconstruction and stabilization. However, an anterior approach should be considered in fractures with initial kyphotic deformation or wedge angle of 20 or more degrees.