The ROBINS-I tool is a risk of [[bias]] tool to assess non-randomized studies of interventions. The relevant chapter in the Cochrane Handbook for Systematic Reviews of Interventions Chapter 25, titled ‘Assessing risk of bias in a non-randomized study’. Up-to-date information from the developers on ROBINS-I is available via the Risk of Bias tools website: https://www.riskofbias.info/  
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A [[systematic literature review]] was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in PubMed, Web of Science and Scopus database to identify comparative studies reporting the outcomes of SP lumbar interbody fusion versus DP. For risk of bias assessment [[ROBINS-I tool]] (Risk of bias in non-randomized studies of interventions)  was used.

Results: Four comparative studies were included from an initial search of 3780 papers. All four studies were retrospective cohort studies comparing outcomes of single-position versus dual-position LLIF. A total of 349 patients were operated using a SP versus 254 DP. All the studies involved reported: operating time, estimated blood loss, length of stay, change in segmental lordosis and complications. From a general perspective, baseline variables were similar in both groups in all the studies and all reported a significant decrease in operative time and length of stays with SP.

Literature comparing single-position versus lateral then prone lumbar fusion shows a tendency towards shorter operating time and hospital stays in single position lumbar fusion, while maintaining similar perioperative outcomes
((Guiroy A, Carazzo C, Camino-Willhuber G, Gagliardi M, Fernandes-Joaquim A, Cabrera JP, Menezes C, Asghar J. Single-position surgery versus lateral-then-prone-position circumferential lumbar interbody fusion: a systematic literature review. World Neurosurg. 2021 Apr 17:S1878-8750(21)00579-9. doi: 10.1016/j.wneu.2021.04.039. Epub ahead of print. PMID: 33878467.)).