Comparison of unilateral versus bilateral pedicle screw fixation in lumbar interbody fusion: a meta-analysis

Purpose This is a meta-analysis to compare the clinical results between unilateral and bilateral pedicle screw (PS) fixation in lumbar interbody fusion. Methods We included published studies with no language and year restrictions. The criteria which Koes et al. designed in 1995 were used to evaluate the risk of bias of the included studies. All data were analyzed by Review Manager 5.1. The primary outcomes included fusion rate and screw complications, and the secondary outcomes were operative time, blood loss, and hospital time. Results A total of five prospective studies with 407 patients were included in the current meta-analysis, and four of them were randomized controlled trials. There was no significant difference between unilateral PS fixation and bilateral PS fixation group in fusion rate and screw complications (fusion rate: OR 0.54, Z = 1.33, P = 0.18, I 2 = 0 %; screw complications: OR 1.45, Z = 0.71, P = 0.48; I 2 = 44 %). In the secondary outcomes, the operative time ( Z = 3.35, P = 0.0008; I 2 = 95 %) and blood loss ( Z = 4.35, P < 0.0001; I 2 = 98 %) was significantly higher in bilateral PS fixation group than in unilateral PS fixation group. Besides, no significant difference was found in hospital time ( Z = 1.19, P = 0.24; I 2 = 99 %). Conclusions In our meta-analysis, we found that unilateral PS fixation in lumbar fusion was as effective as bilateral PS fixation for lumbar degenerative diseases without major instability, no significant difference was found in hospital time, fusion rate and screw complications. In terms of operative time and blood loss, unilateral PS fixation even produced better results.