277 Stereotactic Localization Enables Spatial Representation-Based Functional Outcome Prediction Following Minimally Invasive Basal Ganglia Hemorrhage Evacuation

INTRODUCTION: Anatomic factors that contribute to poor outcomes following minimally invasive surgical (MIS) evacuation for basal ganglia intracranial hemorrhage (bgICH) are poorly understood. METHODS: We performed a retrospective single-center review of patients undergoing MIS bgICH evacuation between 2013-2014. Good outcome was defined as modified Rankin Scale (mRS) between 0-3 within one year of surgery. On volumetric CT-scans (axial slice height <1.25-mm), all bgICHs were manually segmented and stereotactically localized using a common anatomic coordinate frame, termed the OTO-space (orbital rim-tentorial incisura-orbital rim). Heat maps that identified differential spatial representation among functional outcome states were generated. Differential bgICH volume overlap was calculated with the heat map for each patient after subtracting out that patient’s contribution to the map. Area under the receiver operating characteristic curve (AUC) was used to evaluate model performance based on differential volume overlap. RESULTS: Poor functional outcome was observed in 32 patients (71% of 45 total patients). Derivative ICH score components including older age (p=0.017), increased ICH volume (p=0.007), NIHSS (p=0.006), and intraventricular hemorrhage severity (via modified Graeb Scale) (p=0.024) were associated with poor outcome. Poor functional outcomes were strongly over-represented in the region of the caudate nucleus, anterior limb/genu of the internal capsule, anterior temporal lobe, and thalamus. Good outcomes were strongly over-represented in the region of the posterior lentiform nucleus. The AUC for differential volume overlap with the dissimilarity heat map was 0.87 (0.69-0.95), which was higher than chance alone (p<0.001), but statistically similar to that (0.82 [0.71-0.97]) of the ICH score (p=0.461, z-test). CONCLUSIONS: Stereotactic bgICH localization enables spatial representation-based functional outcome prognostication in patients undergoing MIS evacuation. Study in medically managed patients may identify anatomic factors that differentially predict outcome according to management strategy.