Study design: Prospective trial.
Objective: To examine the bone union and clinical results after unilateral or bilateral instrumented posterolateral fusion surgery using a local bone graft.
Summary of background data: The iliac crest bone graft technique for lumbar posterolateral fusion surgery is widely used; however, donor site problems such as pain and sensory disturbance have been reported. Local bone has been used for bilateral multisegment fusion surgery; however, outcomes have been poor because of insufficient amounts of local bone used. This study evaluated unilateral and bilateral posterolateral fusion at 3 levels using a local bone graft.
Methods: Sixty-two patients diagnosed with degenerated spondylolisthesis at 3 levels were divided into 2 groups. All underwent decompression and bilateral instrumented posterolateral fusion. However, a unilateral local bone graft was used in 32 patients and bilateral local bone graft was used in 30 patients. The amount of bone grafting, proportion of patients with bone union, duration of bone union, visual analog scale score, Japanese Orthopedic Association score, and Oswestry Disability Index were evaluated before and 2 years after surgery.
Results: Visual analog scale score, Japanese Orthopedic Association score, and Oswestry Disability Index were not significantly different between the 2 groups before and after surgery (P > 0.05). The amount of local bone graft used for each segment was significantly less in the bilateral group (P < 0.05). The proportion of patients with rates of bone union and instability were 86% and 9%, respectively, in the unilateral group, but significantly poorer at 60% and 34% in the bilateral group.
Conclusion: If multisegment fusion (3-level fusion) is performed, bilateral local bone grafting results in a poor rate of bone union because of an insufficiency of local bone. Unilateral bone grafting is recommended because better rates of bone union and stability are achieved.