Robot-assisted vs conventional lumbar interbody fusion: A systematic review and meta-analysis of perioperative, radiographic, and clinical outcomes

Table 7 Summary of findings and Grading of Recommendations Assessment, Development and Evaluation evidence quality assessment

Outcome	Number of studies	Study design(s)	Risk of bias	Inconsistency	Indirectness	Imprecision	Publication bias	Overall quality (GRADE)	Comments/explanation
Screw accuracy (grade A)	1 RCT, 21 observationals	RCT, observational	Moderate	Not serious	Not serious	Not serious	Undetected	Moderate	Consistent large effect across multiple studies despite observational nature
Operative time	1 RCT, 17 observationals	RCT, observational	Moderate	Serious	Not serious	Serious	Undetected	Low	Risk of confounding and moderate heterogeneity across studies (I2 = 66%)
Blood loss	1 RCT, 17 observationals	RCT, observational	Low	Not serious	Not serious	Not serious	Undetected	Low	Multiple studies had critical ROBINS-I domains; small-to-moderate effect size
FJV	1 RCT, 12 observationals	RCT, observational	Moderate	Not serious	Not serious	Not serious	Undetected	Moderate	RA reduced FJV rates by 50%-75%
Sagittal alignment	0 RCT, 7 observationals	Observational	Moderate	Serious	Not serious	Serious	Undetected	Low	Limited data; heterogeneous measurements
Patient-reported outcomes	1 RCT, 14 observationals	RCT, observational	Moderate	Not serious	Not serious	Not serious	Undetected	Moderate	No long-term differences between RA and comparators

Certainty of evidence was rated using the Grading of Recommendations Assessment, Development and Evaluation approach. “Moderate” certainty was retained only when effect sizes were consistent and robust despite observational design. Downgrades were applied based on risk of bias in non-randomized studies of interventions assessments (e.g., selection bias, confounding, missing data), statistical heterogeneity, and inconsistency where applicable. Radiation dose was excluded from formal grading due to incompatible outcome units (e.g., mGy, μSv, exposure time, image count). GRADE: Grading of Recommendations Assessment, Development and Evaluation; RCT: Randomized controlled trial; ROBINS-I: Risk of bias in non-randomized studies of interventions; RA: Robot-assisted; FJV: Facet joint violation.