Comparing robotic and open partial nephrectomy under the prism of surgical precision: a meta-analysis of the average blood loss rate as a novel variable

Abstract

Exploration of surgical precision in robotic procedures is extensive, yet lacks a unified framework for comparability. This study examines tissue handling precision by comparing the per-minute blood loss rate between robotic and open partial nephrectomy. A literature search from August 2022 to June 2024 identified 43 relevant studies providing data on estimated blood loss and procedure duration. The expected values and standard errors of these variables were used to compute the per-minute blood loss rate (Q). Meta-analytical methods estimated pooled and subgroup-level mean differences, favoring robotic surgery (MD_Q = - 1.043 ml/min, CI_95% = [- 1.338; - 0.747]). Subgroup analyses by publication year, patient matching, referral center count, and ROBINS-I status consistently supported this advantage. Sensitivity analyses confirmed the above benefit in studies with increased accuracy in reported results (MD_Q = - 0.957 ml/min, CI_95% = [- 1.269; - 0.646]), low risk of bias involving matched comparisons (MD_Q = - 0.563 ml/min, CI_95% = [- 0.716; - 0.410]), large sample sizes and increased statistical power (MD_Q = - 0.780 ml/min, CI_95% = [- 1.134; - 0.425]), and multicenter analyses with patient matching (MD_Q = - 0.481 ml/min, CI_95% = [- 0.698; - 0.263]). The subsequent analysis of correlation between the original variables suggested a slight reduction in the robotic advantage when the latter were proportionally related. Multilevel meta-regression at both temporal and qualitative scales consistently indicated a comparative benefit of the robotic approach. Potentially, lower per-minute blood loss compared to open surgery suggests that robotic partial nephrectomy demonstrates enhanced precision in tissue handling.

Keywords: Nephron-sparing surgery; Partial nephrectomy; Robot-assisted surgery; Robotic surgery; Surgical precision.

Fig. 1

Flowchart of studies according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). From: Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;3 72:n71. https://doi.org/10.1136/bmj.n71

Fig. 2

Comprehensive chart featuring an embedded map displaying the percentage distributions of studies and patients by their respective countries of origin

Fig. 3

Pie charts depicting the percentage distributions of available data for studies and patients, respectively, categorized by publication year (a), adoption of patient matching (b), number of referral centers involved (c) and ROBINS-I class (d)

Fig. 4

Histogram illustrating the percentages of pooled studies corresponding to each quality grading class according to the Newcastle–Ottawa Scale (a). Summary plot illustrating the evaluation of all incorporated studies using the ROBINS-I tool, presenting their percentages stratified by the risk of bias level within each of the seven domains (b)

Fig. 5

Scatter plots depicting the EBL–OT pairs for the two compared surgical approaches (RPN/RAPN vs. OPN). Each diagram is accompanied by the corresponding correlation, represented by a dashed regression line. It is noted that the plots were constructed using the expected values for each variable from each arm of every included study

Fig. 6

Forest plot showing the comparative effect as the mean difference in Q (MD_Q) between RPN/RAPN and OPN for all included studies

Fig. 7

Funnel plot presenting the publication bias assessment in all the examined studies, incorporating a curved regression line to investigate for small study effects (a). Radial plot complemented with an integrated regression line, to assess the significance of publication bias using the Egger's test (b). Meta-regression analysis plots showing the change in the comparative effect (MD_Q) between RPN/RAPN vs. OPN, along with the CI_95%, in the aggregated studies, using as moderator the publication year (c) and the score in quality stars based on the NOS scale (d)

Fig. 8

Forest plot showing the comparative effect as the mean difference in Q (MD_Q) between RPN/RAPN and OPN in the subset of studies with increased accuracy of reported results,  isolated at the first level of the sensitivity analysis

Fig. 9

Funnel plot presenting the publication bias assessment in the subset of studies corresponding to the first level of the sensitivity analysis, that incorporates a curved regression line to investigate for small study effects (a). The respective radial plot with an embedded regression line, to assess the significance of publication bias using the Egger's test (b). Meta-regression analysis plots showing the change in the comparative effect (MD_Q) between RPN/RAPN vs. OPN, along with the CI_95%, in the subset of studies corresponding to the first level of the sensitivity analysis using as moderator the publication year (c) and the score in quality stars based on the NOS scale (d)

Fig. 10

Plot depicting the variation in the comparative effect (MD_Q) between RPN/RAPN and OPN, along with its CI_95%, for consecutive r-values, at the  fifth level of the sensitivity analysis and for the total of included studies