Objective Hydrosoft coils were developed to serve as finishing coils to prevent aneurysmal recurrence at the neck. Initial animal studies were encouraging since some studies showed endothelial healing across the neck without recurrence over time. However, theoretical concerns exist regarding the potential threat to parent vessels as the Hydrosoft coils at the neck expand, as well as whether such coils can be adequately supple to safely serve as a true finishing coil. A retrospective review of the initial clinical experience utilizing Hydrosoft coils from three high-volume centers was performed.

Methods Each center was asked to report angiographic (aneurysmal location, aneurysmal maximal size, neck size, incidence of intraprocedural parent vessel thrombosis, coil herniation, aneurysmal rupture as well as Raymond scale and percent occlusion after coiling) and clinical (rupture status, Hunt and Hess grade, incidence of stroke, hemorrhage, vasospasm and hydrocephalus) data on consecutive patients who underwent placement of Hydrosoft coils.

Results A total of 141 patients were enrolled. Embolization achieved a Raymond Scale score of I (complete obliteration) in 79 aneurysms (56%), II (residual neck) in 40 aneurysms (28%) and III (residual dome) in 21 aneurysms (15%); in one case the Hydrosoft coil could not be placed. Procedural morbidity and mortality were 2.1% and 1.4%, respectively. No complications were definitively attributed to the use of Hydrosoft coils. There were three cases (2.1%) of parent vessel thrombosis, two of which resolved after intraprocedural administration of thrombolytic agents and did not lead to neurological sequelae. The incidences of intraprocedural or periprocedural aneurysmal rupture (2.1%), cerebral hemorrhage (3.5%), stroke (4.9%), vasospasm (26.2%) or hydrocephalus (31.1%) were comparable to contemporary literature.

Conclusion The use of Hydrosoft coils appears to be safe and does not lead to higher complication rates than are currently accepted in the literature. Further prospective studies are required to determine whether the use of Hydrosoft coils results in a lower incidence of aneurysmal recurrence.