Technical challenges to surgical clipping of aneurysmal regrowth with coil herniation following endovascular treatment – a case report

In recent years, technical developments have made endovascular procedures attractive therapeutic options and enabled the endovascular surgeon to redefine the management of cerebral aneurysms. However, as the number of aneurysms undergoing endovascular therapy has grown, so has the number of patients with incompletely treated aneurysms who are presenting for further management. In cases of failure of endovascular treatment caused by either incomplete occlusion or regrowth of the aneurysm, a complementary treatment is often necessary. Surgical treatment of these patients is challenging. We present a case of a ruptured posterior cerebral artery aneurysm treated initially with endovascular coiling that left behind significant residual aneurysmal sac. Regrowth of the aneurysm documented on follow-up was treated surgically. At surgery, the coil was found to have herniated through the aneurysmal sac into the subarachnoid space, and the aneurysm was successfully clipped without removing the coils. We review the regrowth of aneurysms following endovascular therapy and potential problems and challenges of surgically managing these lesions.