Unilateral versus bilateral pedicle screw fixation in minimally invasive transforaminal lumbar interbody fusion: a systematic review and meta-analysis of randomized controlled trials

Introduction: The minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) that adopts paramedian incisions and tubular retractors to perform the decompression and interbody fusion has been widely used in the surgery for lumber degenerative disease (LDD). Bilateral pedicle screw fixation (BPSF) and unilateral pedicle screw fixation (UPSF) are the primary fixing techniques in MIS-TLIF. We conducted an updated systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the efficacy and safety between UPSF and BPSF in patients undergoing MIS-TLIF surgery for LDD. Materials and methods: We searched the PubMed, Embase, and Cochrane Library databases for potential RCTs till June 2023. The effects of the fixation methods on clinical outcomes were estimated using the odd ratio (RR), risk difference (RD), and mean difference (MD) with a 95% confidence interval (CI) and a random-effects model. Results: We obtained six RCTs. There was no significant difference between UPSF and BPSF in fusion rate, hospitalization day, low back pain, leg pain, Oswestry Disability Index, and SF-36 for physical functioning at 3–6 months and ≥ 6 months after surgery. Neither the total complication nor the individual complications showed differences between the two methods. However, UPSF significantly decreased operation time (MD = − 39.05; 95% CI: − 53.50 to − 24.67) and estimated blood loss (MD = − 60.41; 95% CI: − 79.09 to − 41.73) compared with BPSF. Conclusion: UPSF is better than BPSF when operation time and estimated blood loss are considered. BPSF may be considered for patients with single-level LDD without high-grade spondylolisthesis.