**2.2 Permanent clipping**

The application of a permanent clip requires the perfect knowledge of aneurysm anatomy, which should follow the Rothon rules [18]:


Different clipping techniques have been described: simple clipping and multiple clipping.

Simple clipping refers to using a single clip for aneurysms with narrow neck and uncomplicated anatomy. It requires the use of the optimal clip in relation to neck conformation and size, considering that the application of the clip pressing the neck will increase its length and that the final part of the blade should cross the neck [12].

Multiple clipping is a technique that allows the application of more than one clip to close the neck of the aneurysm in sequential steps, and it is usually adopted to treat aneurysms with complex anatomy, including intersecting clips, stacked clips, and overlapping clips [12]. *Intersecting clipping* technique describes the application of the second clip angled into the first clip and intersecting it, thus allowing the remodeling of the aneurysm with a *bleb* that otherwise would be impossible to exclude with a simple clipping (**Figure 1A)** [19, 20].

*Stacked clipping* consists of the application of clips in the same direction and parallel to each other, in which usually the first one closes the aneurism, and the other ones closes the remnant *of the neck* beneath to the first clip (understacked). In case of application of the first clip on the neck, if another clip is necessary over the first one to complete the closure, this is defined overstacked (**Figure 1B**) [12, 20, 21].

*Overlapping clipping* describes the application of a second fenestrated clip over a first straight clip encircling it, in order to close a distal remnant beneath the initial clip (**Figure 1C**) [12, 20].

*Tandem clipping* is the technique described by Drake, which consists of the application of a first straight fenestrated clip to close the distal aneurysm (encircling in the fenestration a parent vessel), and a second clip to close the fenestration (**Figure 1D**) [12, 20, 21].

*Clipping Strategies and Intraoperative Tools to Detect Aneurysm Obliteration and Cerebral… DOI: http://dx.doi.org/10.5772/intechopen.110774*

**Figure 1.** *The figure depicts the most common techniques for permanent clipping of cerebral aneurysms.*
