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Robot-assisted aspiration improves survival over conservative treatment in critical primary brainstem hemorrhage: a multicenter, volume-stratified cohort study

Year: 2026

Type: article

Abstract: Background The optimal management of critical primary brainstem hemorrhage (PBSH, hematoma volume 5–15 mL) remains controversial. While minimally invasive surgery shows promise, multicenter evidence—particularly stratified by hematoma volume—is lacking. This study aimed to evaluate the survival benefit and safety of frameless robot-assisted aspiration compared to conservative treatment in patients with critical PBSH. Methods We conducted a multicenter, retrospective cohort study involving 79 consecutive patients [Glasgow Coma Scale (GCS) 3–8] admitted to three neurosurgical centers between May 2022 and October 2025. Patients were allocated to a robot-assisted aspiration group ( n = 38) or a conservative care group ( n = 41). Further stratification was performed based on initial hematoma volume (5–10 mL, n = 63; >10 mL, n = 16). Volumetric measurements were performed by two independent neurosurgeons blinded to outcomes, demonstrating excellent inter-rater reliability (intraclass correlation coefficient = 0.96). Primary outcomes included 30-day and 90-day survival rates, analyzed using Kaplan-Meier curves and Cox proportional hazards regression. To rigorously control for potential treatment selection bias inherent in a retrospective cohort design, a 1:1 propensity score matching (PSM) sensitivity analysis was additionally performed. Results Baseline characteristics, including age, GCS score, and hemorrhage location, were comparable between groups. Safety profiles, including rebleeding (7.89% vs. 4.88%) and intracranial infection rates, were similar (all p > 0.05). In the overall cohort, the robot-assisted aspiration group exhibited a significantly higher 30-day survival rate (76.3% vs. 43.9%, p = 0.006). Stratified analysis revealed that the survival benefit was confined to the 5–10 mL subgroup, where robot-assisted aspiration significantly improved 30-day (82.1% vs. 45.7%, p = 0.004) and 90-day survival (71.4% vs. 42.9%, p = 0.044), alongside improved discharge GCS scores. In the >10 mL subgroup ( n = 16), 30-day survival was 60.0% (6/10) vs. 33.3% (2/6) — an absolute difference of +26.7 percentage points (95% CI: −19.9 to +59.8; Fisher's exact p = 0.61; post-hoc power 0.28). This subgroup was underpowered and the result is inconclusive rather than negative. Multivariable Cox regression confirmed robot-assisted aspiration as an independent protective factor (hazard ratio = 0.494, 95% CI: 0.245–0.997, p = 0.049), reducing mortality risk by 50.6%. In the PSM sensitivity cohort (34 matched pairs; 68 patients in total), robot-assisted aspiration still showed a significant survival benefit, reducing the risk of 90-day death by 60.0% (adjusted HR = 0.400, 95% CI: 0.195–0.822, p = 0.013). Volume stratification confirmed significant surgical benefits with respect to both survival and neurological function in the 5–10 mL subgroup (90-day survival rate: 73.1% vs. 32.1%, p = 0.003; distribution of mRS grades: p = 0.034), whereas the outcomes of the two treatment groups converged in the >10 mL subgroup (37.5% vs. 33.3%, p = 1.000). Conclusions Robot-assisted aspiration is a safe intervention for critical PBSH and is associated with improved survival over conservative care — an association that persisted after propensity score matching — particularly within the 5–10 mL volume window. In hematomas larger than 10 mL the study was inconclusive: the point estimates favored aspiration but the subgroup was underpowered ( n = 16; n = 14 after propensity score matching) and the confidence intervals included no benefit. Long-term functional outcomes were dominated by severe disability or death in both treatment arms regardless of volume. These findings suggest—rather than prove—a volume-dependent therapeutic window, underscoring the need for prospective validation to guide stratified neurocritical care.

Source: Frontiers in Neurology

DOI: 10.3389/fneur.2026.1954969