Background and purpose: The HydroCoil is an expansile hydrogel coil designed to produce a greater degree of volumetric packing within cerebral aneurysms when compared with bare platinum coils. This increased packing is, in turn, believed to decrease the risk of recurrence within aneurysms and hence the risk of their rupture in the long term. The aim of this work was to assess whether the use of HydroCoils and the proportion of HydroCoil used have any influence on the subsequent occlusion and recurrence rates of treated aneurysms.
Materials and methods: A retrospective study was performed of 328 patients during 5 years at a single institution. The initial angiographic and follow-up angiographic occlusion rates were recorded as were any procedural complications. The proportion of HydroCoil used was described as the relative amount of HydroCoil length to the total coil length used during an aneurysm treatment, thus forming 4 groups: 0%-19%, 20%-49%, 50%-69%, 70%-100%, and the subgroups with 100%.
Results: Two hundred seventy patients had angiographic follow-up during an average of 13 months. The overall risk of permanent neurologic deficit and death was 3%. The rate of complete occlusion was 31% immediately postcoiling and 64.8% on follow-up. At the latest follow-up, 25.6% had residual necks and 9.6% had residual aneurysms. There was a statistically significant trend for HydroCoils to produce greater occlusion rates on follow-up when >70% HydroCoil was used (P = .025). The overall rate of recurrence for all aneurysms as a group was 15.5%. The retreatment rate was 6.6%. There has been 1 rebleed in the 328 patients.
Conclusions: The overall results following the use of HydroCoils to occlude aneurysms compare well with those in other reported series. HydroCoils do produce a statistically significantly greater rate of occlusion when >70% of total aneurysm coil length is HydroCoil compared with coiling with <20% HydroCoil. There was no significant difference, however, in the recurrence or retreatment rate when comparing these groups.