**1. Introduction**

Once considered as the definitive curative option for intracranial aneurysms (IAs), clipping has steadily lost its footing in the face of the less invasive and lowerrisk-laden endovascular procedures. Successful clipping implies completely occluding the aneurysmal sack at its origin on the parent artery, significantly diminishing the risk of rupture and ensuing morbidity. The procedure is especially indicated for ruptured aneurysms. However, there is ongoing debate regarding the necessity for surgery in the case of unruptured intracranial aneurysms (UIAs). Since many of these patients also harbor more than one aneurysm, another controversial aspect in neurosurgery is whether to treat all aneurysms in the same session or to leave the unruptured lesions for a delayed intervention or even for an endovascular

procedure. In this chapter, we present our considerable experience and attitude in the surgical management of unruptured and multiple aneurysms.

Preventing rupture from IAs represents a major concern for neurosurgeons, neuroradiologists, and neurointerventionists, as this represents a catastrophic and potentially life-threatening occurrence in the natural history of this pathology. UIAs are defined as not possessing a known history or signs of rupture or that have been diagnosed incidentally for symptoms unrelated to intracranial hemorrhage. They are a veritable "ticking time bomb" that, under certain conditions, can "detonate" and cause a devastating hemorrhagic stroke with severe and often irreversible consequences. Therefore, preventive surgical treatment of UIAs, especially clipping of the aneurysmal sack, is a valuable and possibly life-saving option.

A successful clipping means that the vascular clip completely isolates the aneurysmal lumen from blood flow at its origin on the parent artery. This point of origin is generally located at either a bifurcation or a sharp turn of an artery. Surgical clipping may prevent rupture of that particular aneurysm, although an incomplete occlusion can result in recurrence. Since the development of less invasive endovascular techniques, clipping has lost most of its standing in the treatment of UIAs, being reserved for hemorrhagic lesions or those otherwise unsuitable for endovascular procedures. Certain highly experienced centers still favor the intracranial approach for UIAs due to the longevity of procedure and excellent postoperative neurological outcome.

Additionally, some patients may harbor more than one aneurysm, occurring either concomitantly or sequentially. These may be diagnosed incidentally, during the rupture of at least one of the aneurysms or at a variable point in time during postprocedural control. The treatment of multiple intracranial aneurysms (MIAs) to this day remains a highly debated topic, lacking a general consensus regarding indications, timing, and modality. Our experience supports the single-stage singleopening surgical treatment of multiple UIAs.
