Purpose: Stent dislocation is a rarely encountered problem in interventional neuroradiology. This article describes the repositioning of a pipeline embolization device (PED) dislocated from the vertebral artery (VA) into the basilar artery (BA) using a stent-in-stent technique. Based on this case additional in vitro measurements were performed.
Methods: In a patient, a larger PED (4.0 × 20 mm) was partially opened in a PED (3.0 × 20 mm) floating freely within the distal BA. The microcatheter with the partially opened stent was pulled back hereby pulling back the stent-in-stent construct into the VA. In vitro the maximum tensile force that could be applied to a 3.5 mm and a 4.5 mm PED before dislodgement out of a 3.0 mm PED was determined. Videomorphometric analyses of the stent-in-stent construct were performed while applying traction to the construct.
Results: Repositioning of a dislocated PED is feasible using a stent-in-stent technique. Higher dislodgement forces can be applied using a larger PED (4.5 mm, 0.36 N) whereas dislodgement occurred faster using a smaller PED (3.5 mm, 0.26 N). Before dislodgement occurs, elongation and tapering of both stents can be seen. Finally, it was found that incidental extraction of the 4.5 mm PED out of the delivering microcatheter during traction is possible.
Conclusions: Repositioning of a lost PED is feasible using a stent-in-stent technique. Principally, dislodgement force is higher using a larger PED, while in this case care has to be taken to avoid incidental extraction of the second PED out of the microcatheter.