Study design:

Meta-analysis.

Objectives:

We performed this meta-analysis to compare the safety of unilateral with bilateral instrumented fusion in two-level degenerative disorders of lumbar spine.

Materials and methods:

We conducted independent and duplicate electronic database search including PubMed, Embase and Cochrane Library till January 2020 for Randomised Controlled Trials(RCTs) comparing unilateral pedicle screw fixation with bilateral pedicle screw fixation for multi-level lumbar degenerative disorders. Fusion and complication rates were the primary outcomes analysed. Analysis was performed in R platform using OpenMeta[Analyst] software.

Results:

5 RCTs including 215 patients(Unilateral/Bilateral=106/109) were included in meta-analysis. There was no significant difference between the two groups regarding fusion rate, complication rate, blood loss, duration of hospital stay, functional outcome scores like Visual Analog Scale(VAS), Oswestry Disability Index(ODI) and Short-Form health survey(SF-36) at final follow-up. Unilateral pedicle screw fixation was associated with a significant reduction in operation time(p<0.001). Compared to open approach, minimally invasive approach showed significant difference in terms of factors like operative time, blood loss, hospital stay, VAS and ODI(p= 0.004).

Conclusion:

Our meta-analysis establishes the immediate safety and significant lesser operative period of unilateral pedicle screw fixation in lumbar fusion. However, due to lack of evidence on complications like cage subsidence and adjacent segment disease, unilateral pedicle screw fixation cannot be recommended as an alternative to bilateral pedicle screw fixation for two-level degenerative spinal disease. Our analysis established the lacunae in literature for high-quality evidence on the subject hence we recommend further large multicentre studies with longer follow-up to arrive at a conclusion.