Early detachment of the Solitaire stent during thrombectomy retrieval: an in vitro investigation
Department of Radiology; New England Center for Stroke Research
Neurology | Radiology
OBJECTIVE: To elucidate the early detachment of the Solitaire stent during mechanical thrombectomy, we tested the stent in vitro under various conditions and evaluated with microscopy.
METHODS: A total of five stents were tested. Using a dynamic mechanical analysis machine, we calculated the tensile force needed for separation of the four stents from the pusher wire. Stent Nos 1 and 2 were tested without any prior manipulation. During the retraction test, no sheathing around the stent-wire junction was applied to stent No 1 whereas stent No 2 was partially covered with a sheath in accordance with instructions for use (IFU) recommendations. Stent No 3 was tested after deployment and retrieval were performed three times in an in vitro vascular replica with sheathing during retrieval. Stent No 4 was tested after one deployment and retrieval using the same replica as in stent No 3 without sheathing. In addition, forward pushing force was applied intentionally during retraction to induce excessive bending of the stent. Stent No 5 was pulled apart by both hands. After separation, stent tips and pusher wires were studied for all stents under the microscope.
RESULTS: The tensile force needed for separation was about 6 N for stent Nos 1, 2, and 3, and about 4 N for stent No 4. All of the stents showed separation at the proximal marker, not at the detachment zone.
CONCLUSIONS: Detachment of the Solitaire stent during thrombectomy can be due to separation around or inside the proximal marker. Adherence to the manufacturer's IFU of partial re-sheathing during retraction and not using the device for more than two passes might decrease the possibility of such device failure.
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Citation: J Neurointerv Surg. 2015 Feb;7(2):114-7. Epub 2014 Jan 16. Link to article on publisher's site
Kwon, Hyon-Jo; Chueh, Juyu; Puri, Ajit S.; and Koh, Hyeon-Song, "Early detachment of the Solitaire stent during thrombectomy retrieval: an in vitro investigation" (2015). Radiology Publications and Presentations. 251.