Robot-assisted aspiration is a safe intervention for critical primary brainstem hemorrhage and is associated with improved survival over conservative care, an association that persisted after propensity score matching and was most evident in the 5-10 mL hematoma volume window, while results for hematomas >10 mL were inconclusive because the subgroup was underpowered.
Key Findings
Results
In the overall cohort, robot-assisted aspiration was associated with higher 30-day survival than conservative treatment.
30-day survival was 76.3% vs. 43.9% (p = 0.006).
Retrospective multicenter cohort of 79 consecutive patients (GCS 3-8) from three neurosurgical centers, May 2022 to October 2025.
38 patients received robot-assisted aspiration and 41 received conservative care.
Baseline characteristics, including age, GCS score, and hemorrhage location, were comparable between groups.
Results
Multivariable Cox regression identified robot-assisted aspiration as an independent protective factor for survival.
Hazard ratio = 0.494 (95% CI: 0.245-0.997, p = 0.049).
This corresponds to a 50.6% reduction in mortality risk.
Primary outcomes were 30-day and 90-day survival, analyzed with Kaplan-Meier curves and Cox proportional hazards regression.
Results
The survival association persisted in a 1:1 propensity score matched sensitivity cohort.
34 matched pairs (68 patients) were analyzed.
Adjusted HR for 90-day death = 0.400 (95% CI: 0.195-0.822, p = 0.013), a 60.0% reduction in risk.
PSM was performed to control for treatment selection bias inherent in a retrospective design.
Results
In the 5-10 mL hematoma subgroup, robot-assisted aspiration significantly improved 30-day and 90-day survival and discharge GCS scores.
The 5-10 mL subgroup comprised 63 patients.
30-day survival: 82.1% vs. 45.7% (p = 0.004).
90-day survival: 71.4% vs. 42.9% (p = 0.044).
Discharge GCS scores were also improved.
Results
In the PSM cohort, the 5-10 mL subgroup showed significant benefit in both 90-day survival and functional (mRS) outcomes.
90-day survival: 73.1% vs. 32.1% (p = 0.003).
Distribution of mRS grades differed significantly (p = 0.034).
Long-term functional outcomes were dominated by severe disability or death in both arms regardless of volume.
Results
In the >10 mL subgroup, the results were inconclusive: point estimates favored aspiration but there was no statistically significant difference.
The subgroup included 16 patients; 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 was 0.28; the authors describe the result as inconclusive rather than negative.
In the PSM cohort (n = 14 in this subgroup), 90-day survival was 37.5% vs. 33.3% (p = 1.000), i.e., outcomes converged.
Results
Robot-assisted aspiration had a safety profile similar to conservative treatment.
Rebleeding occurred in 7.89% vs. 4.88% of patients.
Intracranial infection rates were similar.
All safety comparisons had p > 0.05.
Methods
Hematoma volume measurements were highly reliable between raters.
Volumes were measured by two independent neurosurgeons blinded to outcomes.
Intraclass correlation coefficient = 0.96.
Conclusions
The authors conclude the findings suggest, but do not prove, a volume-dependent therapeutic window needing prospective validation.
The benefit was confined to the 5-10 mL stratum, with the >10 mL stratum underpowered.
The study is retrospective, so residual selection bias cannot be excluded despite PSM.
Prospective validation is called for to guide stratified neurocritical care.
What This Means
This study looked at 79 patients with serious bleeding in the brainstem (the part of the brain controlling breathing and consciousness) at three hospitals. Some patients had the blood removed by suction using a robot-guided needle approach, and others received standard non-surgical care. Patients who had the robot-assisted procedure were more likely to be alive at 30 days (about 76% vs. 44%), and the survival advantage was still seen after statistically matching similar patients to reduce bias.
The benefit appeared mainly in patients with smaller bleeds (5-10 mL), where survival at 30 and 90 days was clearly higher with surgery. For larger bleeds (over 10 mL), the numbers were too small (16 patients) to draw any conclusion; the results leaned toward benefit but could not rule out no difference. Complication rates such as rebleeding and infection were similar between the two groups. However, many survivors in both groups were left with severe disability.
This research suggests that robot-assisted aspiration may be a safe option that improves survival in some patients with critical brainstem hemorrhage, especially smaller bleeds. Because the study looked back at past records rather than randomly assigning treatment, it cannot prove that the surgery caused the better survival. Larger prospective studies are needed to confirm these findings.
Guo H, Wang X, Li J, Che S, You Q, Gao S, et al.. (2026). Robot-assisted aspiration improves survival over conservative treatment in critical primary brainstem hemorrhage: a multicenter, volume-stratified cohort study.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1954969