39 patients suffering from single-segment, low-grade, degenerative lumbar instability with unilateral radicular symptoms were randomly allocated to a unilateral or bilateral pedicle screw fixation group. Patients in the unilateral group were operated on using the Wiltse approach, and patients of the bilateral group were operated on using the posterior midline approach. Blood loss and clinical outcomes, including (VAS) back and leg pain scores, Japanese Orthopaedic Association (JOA) scores, and Oswestry Disability Index (ODI) scores, were compiled and analyzed. Results revealed that unilateral fixation via the Wiltse approach through a tubular retractor appears to be an effective surgical option for patients suffering from degenerative lumbar instability.