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Introduction Patients with acute ischemic stroke due to large vessel occlusion (LVO) and poor collateral circulation face rapid infarct progression and poor outcomes. This subgroup was underrepresented in early thrombectomy trials, creating a treatment grey zone.Aim of Study To review and synthesize current evidence on mechanical thrombectomy (MT) in poor-collateral LVO stroke, assess outcomes, imaging strategies, procedural approaches, and future directions.Method We conducted a comprehensive narrative review of randomized trials, meta-analyses, and observational studies focusing on MT in patients with poor collaterals and evaluated collateral assessment techniques, trial outcomes, procedural modifications, and emerging adjunctive therapies across both anterior and posterior circulation strokes.Results Recent trials such as SELECT-2 and ANGEL-ASPECT demonstrated that thrombectomy significantly improves 90-day outcomes even in patients with ASPECTS 3–5 or core volumes ≥70 mL (e.g., mRS 0–2 in 20–31% vs 7–12% with medical therapy). In RESCUE-Japan LIMIT, functional independence was achieved in 32% of MT patients despite large infarcts. Posterior circulation trials like ATTENTION and BAOCHE reported doubled rates of favorable outcomes (mRS 0–3: 46% vs 23%) and reduced mortality with MT. Imaging modalities like multiphase CTA and CT perfusion improve risk stratification. Rapid, first-pass recanalization is crucial in poor-collateral cases.Conclusion Thrombectomy should not be dismissed outright in poor-collateral LVO strokes. While risks are higher and benefits modest, timely intervention can lead to meaningful recovery in selected cases. Advanced imaging, individualized decision-making, and multimodal strategies may help shrink the grey zone.Conflict of Interest No