This meta-analysis compared the effectiveness of instrumented posterior lumbar interbody fusion (iPLIF) versus instrumented posterolateral fusion (iPLF) in treating degenerative lumbar disease-related low-back pain (LBP). Nine studies (3 randomized controlled trials and 6 comparative studies) were identified for this analysis. The results revealed that both fusion techniques effectively and similarly reduced low back pain. However, moderate-quality evidence suggested that posterior interbody fusion led to higher fusion rate and better restoration of spinal alignment in comparison to posterolateral fusion.