From manual to robotic: the evolution of pedicle screw placement techniques in obese patients with degenerative lumbar spine disease—a systematic review

The global obesity epidemic and aging population have increased the number of obese patients with degenerative lumbar disease requiring pedicle screw fixation. Traditional freehand fluoroscopy faces accuracy and radiation challenges in this population. Whether robot-assisted techniques offer consistent advantages remains unclear. To systematically compare the accuracy, operative efficiency, radiation exposure, and complication rates of three pedicle screw placement techniques (conventional fluoroscopy-guided freehand, intraoperative 3D navigation, and robot-assisted) in obese patients undergoing lumbar surgery for degenerative conditions. PubMed, Embase, and Web of Science were searched for English-language articles published between January 1, 2016 and April 1, 2026. We included comparative studies (retrospective or prospective cohorts) that enrolled predominantly obese adults (mean BMI ≥ 30 kg/m 2 ) undergoing posterior lumbar fusion for degenerative disease, or from which extractable obese subgroup data (BMI ≥ 30 kg/m 2 ) were available. Studies had to report at least one of the following outcomes: screw placement accuracy, operative time, radiation dose, or complications. Case reports, case series without a comparator, and cadaveric and animal studies were excluded. Obese patients with degenerative lumbar stenosis, disc herniation, spondylolisthesis, or degenerative scoliosis. Interventions were robot-assisted pedicle screw placement (e.g., Mazor X, ExcelsiusGPS). Comparators were conventional two-dimensional fluoroscopy-guided freehand technique or intraoperative 3D navigation (O-arm, CBCT, or CT-based navigation). Screw placement accuracy (Gertzbein-Robbins grade A/B), total or per-screw operative time, radiation exposure (fluoroscopy time or dose), and complication rates (pedicle breach, infection, bleeding/transfusion, reoperation). Eight studies were included. Regarding accuracy, the single head-to-head comparison between robotics and intraoperative 3D navigation reported comparable rates. Another study found that intraoperative 3D navigation was associated with higher accuracy than conventional fluoroscopy in obese patients. In the only direct comparison between robotics and fluoroscopy, the overall error rate was numerically lower with fluoroscopy; however, this group had one screw requiring revision, whereas the robotic group had none. Regarding surgical efficiency, robotics was associated with shorter operative times than intraoperative 3D navigation in some studies, with faster per-screw placement. Navigation cases were longer than fluoroscopy cases. Robotics was associated with reduced fluoroscopy time compared to intraoperative 3D navigation, and image-guided techniques were associated with reduced surgeon radiation exposure compared to fluoroscopy. Navigation was associated with lower complication odds. Blood loss was lower with robotics than with intraoperative 3D navigation in one study, with a non-significant trend in the same direction in another. Robotics was associated with shorter hospital stay compared to navigation or open controls. Given that these findings derive from individual studies rather than pooled estimates, and the overall certainty of evidence is very low (GRADE⊕⊝⊝ ⊝), they should be interpreted as exploratory. Given the very low certainty of the current evidence (GRADE⊕⊝⊝ ⊝), findings should be interpreted as exploratory rather than conclusive. Robotics and intraoperative 3D navigation were associated with comparable accuracy, and both showed potential advantages over conventional fluoroscopy in anatomically challenging cases. Robotic techniques may be linked to improved operative efficiency compared to navigation, particularly in multilevel constructs, and were associated with reduced surgeon radiation exposure without an apparent increase in complication rates. However, these observed associations are derived from observational studies at serious risk of bias, and the true effect sizes remain highly uncertain. Overall error rate alone may not fully reflect clinical significance, and accuracy should be interpreted alongside breach severity and revision requirements. Given the exploratory nature of these findings, clinical decisions should be guided by local expertise and patient-specific factors rather than by a generalized preference for any single technique. Future well-designed comparative trials are warranted. Trial registration : This systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD420261387505.