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Robot-assisted versus conventional posterior lumbar interbody fusion for lumbar spinal stenosis: a propensity score-matched cohort study on total and hidden blood loss

Year: 2026

Type: article

Abstract: BACKGROUND: Hidden blood loss (HBL) represents an important component of perioperative bleeding after posterior lumbar interbody fusion (PLIF), especially in multilevel procedures. Whether robot-assisted PLIF (R-PLIF) is associated with lower total blood loss (TBL) and HBL than conventional PLIF remains uncertain. METHODS: This was a single-center retrospective cohort study of consecutive patients who underwent robot-assisted PLIF (R-PLIF) or conventional PLIF between January 2019 and December 2023. After common-support restriction and 1:1 propensity score matching with an exact-match constraint on fused levels, 102 R-PLIF cases were matched to 102 controls; 58 patients fell outside the region of overlap and 138 additional eligible patients were not retained because no acceptable match was available under the prespecified caliper. TBL was calculated using Nadler's and Gross's formulae; visible blood loss (VBL) was defined as intraoperative loss plus postoperative drainage; HBL was derived rather than directly measured, using HBL = TBL - VBL + transfusion volume; the postoperative hematocrit used for the Gross calculation was obtained on postoperative day 1 (within 24 h). A linear model with robust standard errors clustered by matched pair was used to assess the interaction between surgical approach and number of levels. RESULTS: TBL was significantly lower in the R-PLIF group (500.5 ± 276.6 mL) than in the PLIF group (629.0 ± 293.0 mL) (MD - 128.4 mL, 95% CI - 148.7 to - 108.1; P < 0.001). Compared with conventional PLIF, R-PLIF was associated with lower VBL (308.1 ± 146.6 vs. 401.4 ± 173.8 mL; P < 0.001) and lower HBL (224.8 ± 175.0 vs. 282.5 ± 194.9 mL; MD - 57.8 mL; P = 0.001). An exploratory approach × level interaction (P < 0.001) suggested that the between-group difference in TBL was larger among patients undergoing ≥ 2-level fusion. CONCLUSIONS: In this propensity score-matched retrospective cohort, R-PLIF was associated with lower estimated TBL, VBL, and formula-derived HBL than conventional PLIF. However, causality cannot be established, residual confounding may persist, and the clinical significance of the approximately 128-mL mean TBL difference remains uncertain. TRIAL REGISTRATION: Not applicable.

Source: Journal of Orthopaedic Surgery and Research

DOI: 10.1186/s13018-026-07066-x

Authors: Junjie Qiao, Xinyao Lv, Yuyu Fan, Ruizhao Zhao, Xiutong Fang

Institutions: Capital Medical University, Beijing Shijitan Hospital

Language: English

Topic: Spine and Intervertebral Disc Pathology

Subfield: Pathology and Forensic Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,090