Table 1 Pros and cons in the STICH trials

Strong points of STICH trials

• Well-designed, well-powered randomized clinical trials

• Multicenter, multinational

• The research question tested was biologically plausible

• Very low rate of missing long-term follow-up

• Adoption of prognosis-based outcome

• The surgical group was limited to patients who had early surgery (within 72 h of hemorrhage and within 24 h of randomization)

• Although the patients, surrogates, and site investigators were aware of treatments’ allocation; the data manager was the only study person that knew patients’ allocation at the coordinating center.

Weak points of STICH trials

• Large cross-over from conservative to surgical group: approximately one quarter of patients in the initial conservative group crossed over to surgery due to delayed neurological deterioration. These patients were more likely to bear hematomas ≥ 50 ml, and those with a predicted poor prognosis

• The clinical uncertain principle: patients were only included if the responsible neurosurgeon was unsure about the clinical benefits of either treatment. Therefore, patients who were considered to benefit from hematoma evacuation were not included in the study. The evaluation and decision were on discretion of responsible neurosurgeon, leading to selection bias. However, including comatose patients with expanding hematomas or brain herniation in the conservative management would not be ethically acceptable, since surgery is likely a life-saving measure for this subset of patients.

• If no patient had crossed over to surgery, the rates of unfavorable outcome and death in the initial conservative management group may have been higher.

• Large number of excluded patients in the STICH II trial (> 3300) because of impaired level of consciousness at the time of randomization, which adds additional selection bias to the study. Patients with preserved level of consciousness are those with less severe hemorrhages, therefore these patients have a higher likelihood of favorable outcome, irrespective of treatment.