Background Recently, an in vitro cerebrovascular occlusion model of the intracranial circulation was developed for testing thrombectomy devices. The Cover accessory (Lazarus Effect; Campbell, California, USA) is a novel nitinol braided mesh device that surrounds the stent retrieval device and thrombus during the retrieval process to help prevent clot fragmentation and embolization. Methods Using the in vitro model, after introducing fresh clot into the middle cerebral artery, we compared rates of target vessel recanalization and embolization in new territories (areas in which clot had not been introduced) achieved with the Solitaire Flow Restoration (FR) stent retriever (Covidien, Irvine, California) in conjunction with the use of a conventional guide catheter (control group), a balloon guide catheter (BGC group), and the Cover device (Cover group). Results In a total of 51 thrombectomy experiments (20 in the control group, 20 in the BGC group, and 11 in the Cover group), successful recanalization (Thrombolysis in Cerebral Infarction 2b-3) was achieved more frequently in the Cover group than in the control group or in the BGC group (p=0.047 and p=0.020, respectively). Embolization of new ( previously unaffected) territories occurred in five (25%) experiments from the control group and in three (15%) experiments from the BGC group, whereas no embolization of new territories was seen with Cover device assisted thrombectomy. Conclusions Application of the Cover device in this experimental model resulted in higher successful recanalization rates, no embolic events, and was more effective than use of the conventional guide catheter or BGC.