Robot-assisted versus open partial nephrectomy in patients with a solitary kidney: a systematic review and meta-analysis of perioperative and functional outcomes

A patient whose renal tumor develops in a solitary kidney has no contralateral organ able to compensate, and therefore offers the clearest setting in which operative injury to the kidney can be studied. Robot-assisted partial nephrectomy (RAPN) has become routine practice among the wider surgical population, yet no systematic appraisal has established whether it is both safe and effective when the tumor is confined to a solitary kidney. To address this gap we conducted a systematic review and meta-analysis comparing perioperative and functional endpoints between RAPN and open partial nephrectomy (OPN) in these patients. Searches of PubMed, Embase, the Cochrane Library and Web of Science covered each database from its first indexed record to August 13, 2026. Studies were eligible if they were retrospective cohorts in which RAPN and OPN were compared head-to-head in patients with a tumor of a solitary kidney. The Newcastle-Ottawa Scale (NOS) was applied to grade the methodological quality of every report that qualified. Four retrospective studies contributed 333 patients with a solitary kidney (153 assigned to RAPN and 180 to OPN). None of the primary comparisons separated the two arms: the 12-month postoperative eGFR preservation rate (MD = - 3.77%, 95% CI - 10.71 to 3.18, p = 0.287), the need for temporary postoperative dialysis (OR = 1.80, 95% CI 0.47 to 6.90, p = 0.391) and CKD stage progression (OR = 1.42, 95% CI 0.67 to 3.00, p = 0.356). Three secondary endpoints did favor the robotic arm: warm ischemia was shorter by a significant margin (WMD = - 2.15 min, 95% CI - 4.20 to - 0.09, p = 0.041), discharge occurred earlier (WMD = - 2.39 days, 95% CI -4.44 to -0.34, p = 0.012 < 0.05), and blood loss was lower (WMD = - 141.88 mL, 95% CI - 277.40 to - 6.37, p < 0.05). No significant difference emerged for operative duration, transfusion requirement, overall, intraoperative or major complications, or the positive surgical margin rate. For tumors arising in a solitary kidney, renal function at 12 months, dialysis requirement, and CKD progression did not differ significantly between the robotic and open approaches. The robotic route nevertheless delivered a shorter hospital stay, briefer warm ischemia and less blood loss, and did so without increasing complications or positive margins. These retrospective, small-sample findings suggest that RAPN may be a reasonable alternative to OPN in carefully selected patients treated at experienced centers, but they do not establish equivalence or confirm safety and effectiveness. These conclusions are limited by the small number of eligible studies and by their retrospective design; prospective, higher-quality evidence is needed before they can be confirmed.