BackgroundPooled individual data from the landmark stroke trials of 2015 conclude that the benefit of endovascular thrombectomy for patients with intracranial arterial occlusion also extends to patients with concomitant (so-called ’tandem') occlusions of proximal vessels. However, there is heterogeneity and debate in the management of these patients, without a clear standard of care. In particular, there is contention regarding whether the proximal or distal lesion should be treated first. We present a case control study and describe the Simultaneous Extracranial, Intracranial Management of (tandem) LESsions in Stroke (SEIMLESS) technique, an efficient approach to the acute ischemic stroke (AIS) patient who presents with tandem lesions (TLs).MethodsWe describe 5 patients, presenting with AIS and TLs between 2015 and 2017, who we treated with SEIMLESS. Cases were reviewed for clinical data, including arterial puncture to intracranial reperfusion, total fluoroscopy time, amount of contrast, age, and gender. Our series was matched to 5 patients treated with the standard ’sequential' approach (angioplasty followed by thrombectomy) in the same time period by the same operator.ResultsArterial access to intracranial recanalization time was significantly shorter in patients treated with SEIMLESS versus those who had angioplasty followed by thrombectomy (39.6±5.9 min vs 85.2±20.6 min; P=0.014). Patients treated ’seimlessly' also received significantly less iodinated contrast (117±13.5 mL vs 213±48.9 mL; P=0.005) and significantly less fluoroscopy time (21.1±5.2 min vs 55.9±17.8 min; P=0.003). There was no difference in the post-procedural Thrombolysis in Cerebral Infarction score for patients treated with SEIMLESS versus the sequential method (p=0.658).ConclusionSEIMLESS is an efficient procedural method that simultaneously treats a distal intracranial occlusion and a more proximal one. Our small case controlled study finds that this technique is feasible and can lead to faster intracranial recanalization compared with the standard ’sequential' method, utilizing less contrast and radiation in the process. Larger studies are needed to verify our findings.