A comparison of the unilateral and bilateral approaches for posterior lumbar interbody fusion was made by measuring the clinical and radiological results.

The clinical outcomes of 22 cases of the unilateral approaches and 26 cases of the bilateral approaches to the lumbar spine were analyzed using Kirkaldy-Willis method. The amount of intraoperative blood loss, surgery time, transfusions as well as postoperative drainage and transfusions were also investigated. The fusion rate, the changes in the height and angles of the disc in the fused segments and lumbar lordotic angles were analyzed radiologically.

Radiologically, there were no significant differences between the two groups in terms of the fusion rate, the changes in the disc height and angles in the fused segments and lumbar lordotic angels. Good or excellent results were observed in 82.1% and 81% of the unilateral and bilateral approach group, respectively. A longer surgery time was needed and the amount of blood loss was larger in the two level bilateral approaches groups.

In a comparison of the unilateral versus bilateral approaches, similar radiological and clinical outcomes were obtained, but significantly less blood loss and surgery time occurred using the unilateral approaches in the two-level fusions. Therefore, a unilateral approaches is particularly useful in multilevel fusions.