Surgical Management of ICH

Surgical treatment of intracerebral hemorrhage (ICH) has been one of the most challenging and debated areas in neurology for decades. After 30 years of largely negative craniotomy trials (STICH I/II), the field has undergone a revolution with minimally invasive surgery (MIS). The publication of ENRICH in 2024 — the first trial to demonstrate functional outcome benefit with MIS — alongside positive signals from MISTIE III, MIND, and SWITCH, has fundamentally shifted the treatment landscape. Surgery in ICH is no longer a question of "if," but rather "who, when, and how."

1. Historical Context: The STICH Trials

The International Surgical Trial in Intracerebral Haemorrhage (STICH, 2005) randomized 1,033 patients with supratentorial ICH to early surgery (within 24 hours, predominantly open craniotomy) vs. initial conservative treatment. No benefit was found (OR 0.89; 95% CI 0.66–1.19; p=0.41), with 26% of the conservative group eventually undergoing surgery.

STICH II (2013) focused on lobar ICH without IVH (503 patients, 2 cm from cortical surface, within 48 hours). Results were again neutral (OR 0.86; 95% CI 0.62–1.20; p=0.37), though a trend toward reduced mortality was observed (OR 0.71). The key problem with both STICH trials was the surgical approach: open craniotomy causes significant collateral brain injury through the access corridor, potentially offsetting any benefit from hematoma removal.

2. MISTIE III: Catheter-Based MIS

MISTIE III (2019) tested the MISTIE technique — stereotactic catheter insertion followed by alteplase irrigation (1 mg Q8h for up to 9 doses) to lyse and drain the clot. The trial enrolled 506 patients with supratentorial ICH ≥30 mL, with 61.5% having deep ICH.

The primary endpoint — mRS 0–3 at 365 days — was not significantly different (45% MIS vs. 41% medical; p=0.33). However, two critical findings emerged:

• Mortality benefit: One-year mortality was significantly lower with MIS (HR 0.67; 95% CI 0.45–0.98; p=0.04) — a 33% relative reduction.
• Residual clot threshold: Patients who achieved a residual clot volume ≤15 mL had significantly better functional outcomes (mRS 0–3: 53% vs. 33% in those with >15 mL remaining; adjusted OR 2.06).

The ≤15 mL threshold became a critical treatment target that influenced subsequent trial designs, including ENRICH. The disconnect between mortality reduction and lack of functional improvement likely reflects the predominance of deep ICH patients, who sustain damage to critical white matter tracts (internal capsule, corona radiata) regardless of clot removal.

3. ENRICH: The First Positive MIS Trial

ENRICH (2024, NEJM) was the landmark trial that finally demonstrated functional benefit with MIS in ICH. This multicenter Bayesian adaptive RCT enrolled 300 patients with moderate-to-large supratentorial ICH (≥30 mL) and randomized them to MIS with the BrainPath device (NICO Corporation) plus medical management vs. medical management alone. Surgery was performed within 24 hours of presentation using a parafascicular, endoscopic approach that follows natural white matter planes to minimize collateral injury.

Key Results

• Primary endpoint (Uw-mRS at 180 days): Significant benefit favoring MIS overall (mean difference 0.095; posterior probability of superiority 0.961).
• Lobar ICH subgroup: Even more pronounced benefit (Uw-mRS difference 0.127; posterior probability 0.981). This subgroup drove the overall result.
• Deep ICH subgroup: Enrollment stopped early based on interim futility analysis — no benefit observed in deep hemorrhages.
• ICU and hospital stay: Surgery reduced ICU stay by 2.8 days and hospital stay by 3.7 days.
• Hematoma evacuation: Median residual clot was 4.2 mL (87% volume reduction), with 82% achieving the ≤15 mL threshold.
• Safety: Surgical complication rate was 3.4%, with no increase in 30-day mortality.

ENRICH is the first trial to definitively establish MIS as a beneficial intervention for lobar ICH. The parafascicular approach — traversing along rather than through white matter tracts — likely accounts for the lower collateral damage compared to traditional craniotomy. Importantly, benefit was shown only in lobar (not deep) ICH, and surgery was performed rapidly (within 24 hours, median ~12 hours).

4. MIND: Artemis Endoscopic Evacuation

MIND (2025, JAMA Neurol) tested the Artemis Neuro Evacuation Device (Penumbra) — an endoscopic aspiration system using neuro-navigation. This open-label trial randomized 236 patients (2:1) with moderate-to-large supratentorial ICH (20–80 mL) within 24 hours to MIS or medical management. Notably, 70.8% had deep ICH and 29.2% had lobar ICH. Enrollment was stopped early — first for lobar ICH (after ENRICH results established benefit), then for deep ICH based on futility projections.

Key Results

• Primary endpoint (ordinal mRS at 180 days): No significant difference between MIS and medical management (underpowered due to early termination).
• Hematoma evacuation: Impressive volume reduction — 81.5% in deep ICH (to 6.0 mL) and 80.4% in lobar ICH (to 8.1 mL). 79.2% achieved residual clot ≤15 mL.
• 30-day outcomes: Improved mRS at 30 days in both deep and lobar cohorts; fewer patients intubated, reduced ICU and hospital stay.
• Perihematomal edema: Substantial reduction in symptomatic PHE with surgery.
• Procedure: Median duration 33.5 minutes, surgical complications at 0.7% at 30 days, conversion to craniotomy 1.4%.

MIND demonstrated that MIS effectively evacuates hematoma and reduces early morbidity, but the 30-day benefits did not translate to 180-day functional improvement — possibly reflecting irreversible early injury in deep ICH, or simply inadequate power due to early termination.

5. SWITCH: Decompressive Craniectomy

SWITCH (2024) asked a fundamentally different question: rather than evacuating the hematoma, can decompressive craniectomy (with or without hematoma removal) improve outcomes by reducing intracranial pressure? This multinational RCT enrolled 201 patients with large deep supratentorial ICH (including thalamic and posterior limb of internal capsule hemorrhages).

Key Results

• Primary endpoint (mRS 0–4 vs. 5–6 at 6 months): Trend favoring surgery (aRR 0.77; 95% CI 0.59–1.01; p=0.057) — narrowly missed significance.
• Mortality: Significantly reduced with surgery (aRR 0.61; 95% CI 0.40–0.92; p=0.02) — a 39% relative reduction.
• Limitations: Stopped early due to funding constraints, prolonged recruitment (>7 years), and some crossover between arms.

6. Intraventricular Hemorrhage: CLEAR III

CLEAR III (2017) tested EVD placement with alteplase irrigation (1 mg Q8h for up to 12 doses) vs. EVD + saline in 500 patients with IVH and obstructive hydrocephalus. The primary endpoint — mRS 0–3 at 180 days — was not significantly different (48% alteplase vs. 45% saline; p=0.71).

However, mortality was significantly reduced with alteplase (18% vs. 29% at 180 days; HR 0.60; p=0.006), and there was no increase in symptomatic hemorrhage (2% vs. 3%). The mortality benefit came at the cost of more survivors with moderate-to-severe disability (mRS 4–5), explaining the neutral functional outcome.

Current AHA guidelines recommend EVD for IVH causing hydrocephalus (Class 1) and consider EVD + alteplase reasonable for reducing mortality (Class 2a), while acknowledging the uncertain functional outcome impact.

7. Posterior Fossa ICH

Cerebellar ICH carries unique risks due to the confined posterior fossa space. Brainstem compression, obstructive hydrocephalus, and rapid neurological deterioration can occur precipitously. Despite the absence of RCT evidence (due to ethical constraints), there is strong clinical consensus:

• Class 1: Surgical evacuation recommended if cerebellar ICH is causing neurological deterioration, brainstem compression, or hydrocephalus — or if hematoma volume ≥15 mL.
• Class 1: EVD for hydrocephalus (may be used alone in small cerebellar ICH without mass effect, or as a bridge to surgery).
• Initial conservative management may be considered for stable patients with small (<15 mL) cerebellar ICH without brainstem compression or hydrocephalus.
• Close neurological monitoring is essential — deterioration can be sudden and fatal.

8. Lobar vs. Deep ICH: Surgical Evidence Summary

9. Trial Comparison Table

References

1. Mendelow AD, et al. Early surgery versus initial conservative treatment in patients with spontaneous supratentorial intracerebral haematomas (STICH). Lancet. 2005;365(9457):387–397.
2. Mendelow AD, et al. Early surgery versus initial conservative treatment in patients with spontaneous supratentorial lobar ICH (STICH II). Lancet. 2013;382(9890):397–408.
3. Hanley DF, et al. Efficacy and safety of minimally invasive surgery with thrombolysis in intracerebral haemorrhage evacuation (MISTIE III). Lancet. 2019;393(10175):1021–1032.
4. Pradilla G, et al. Trial of early minimally invasive removal of intracerebral hemorrhage (ENRICH). N Engl J Med. 2024;390(14):1277–1289.
5. Arthur AS, et al. Minimally invasive surgery vs medical management alone for intracerebral hemorrhage: The MIND randomized clinical trial. JAMA Neurol. 2025;82(11):1113–1121.
6. Fischer U, et al. Decompressive craniectomy plus best medical treatment versus best medical treatment alone for spontaneous supratentorial intracerebral haemorrhage (SWITCH). Lancet. 2024;404(10449):XXX–XXX.
7. Hanley DF, et al. Thrombolytic removal of intraventricular haemorrhage in treatment of severe stroke (CLEAR III). Lancet. 2017;389(10069):603–611.
8. Greenberg SM, et al. 2022 Guideline for the Management of Patients With Spontaneous ICH. Stroke. 2022;53(7):e282–e361.