**4. Treatment strategies**

The purpose of active treatment for UIAs is to permanently and safely occlude the aneurysmal lumen while preserving the normal cerebral vasculature. In order to achieve this, two types of approaches have been conceived: surgical (via craniotomy), which includes clipping and bypass procedures, or endovascular. As certain lesions cannot be safely and efficiently removed from arterial circulation either by clipping or by endovascular procedures, bypass surgery has been elaborated to remove the aneurysm and its parent vessel, without sacrificing arterial supply to the involved tissues.

Currently, there are no controlled randomized studies that single out the superior form of treatment for UIAs. Optimal treatment should focus on the following aspects:


Since the majority of studies in the reported literature are retrospective in nature, they may suffer from bias. As of yet, the best sources of information regarding the outcome of UIA treatment originate from comparative studies between natural history and complication rates of certain therapies [60]. As our surgical experience exceeds that of endovascular procedures, as well as our standing concerning its importance in the prevention of rupture, we will exclusively present the technical breakdown of aneurysm clipping, according to our practice.

#### **5. Aneurysm clipping: technical breakdown**

Although seemingly easy in theory, placing a clip at the neck of the aneurysm (i.e., its point of origin) represents a genuine surgical challenge because of the need

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relaxation.

**5.4 Dura mater incision**

*Preventing Rupture: Clipping of Unruptured Intracranial Aneurysms*

to preserve the anatomical and functional integrity of the normal vasculature, brain parenchyma, and cranial nerves. This not only implies a good proximal control of the arteries but also adequate exposure of the aneurysm and the vessels, beginning with the craniotomy. In the following paragraphs, we describe the key points of

This is a crucial stage that can either facilitate or hinder the surgical intervention. The patient is placed in a dorsal decubitus. The patient's head should be positioned so that the planned craniotomy is easy to perform, while ensuring that there is no substantial jugular compression (i.e., if the head is rotated excessively to one side) or that proper ventilation is not impeded (i.e., much too little distance between the tip of the mandible and the sternum). The head can be immobilized by a headholder, if this does not hamper venous drainage. We recommend shaving the head, or at the very least the area around the incision, to minimize the risk of infection. Using cutaneous antiseptics such as iodine solution or chlorhexidine, the skin must be thoroughly cleansed, with special attention toward the auricle and the external ear canal.

The skin incision should always be larger than the bone opening, considering the possible need to enlarge the craniotomy. A wide enough craniotomy must be performed for an ideal surgical exposure. Brain relaxation increases visibility and motility, while also diminishing the risk of damaging the brain and vessels. This is vital for certain aneurysms, especially of the skull base (internal carotid artery (ICA), anterior communicating artery (AcoA), basilar apex, etc.) or when attempting to clip mirror aneurysms during the same opening. There are a few methods to achieve brain relaxation, such as hyperventilation, cerebrospinal fluid (CSF) drainage (realized via lumbar drainage or ventriculostomy), intracisternal drainage (the most effective form of intraoperative brain relaxation in our experience, performed by opening the basal cisternae and the

The bone opening should be entirely adapted to the location, size, and morphology of the aneurysm. It must be able to reveal the Circle of Willis and be spacious enough to allow the exploration of the main blood vessels. The most commonly used craniotomy for aneurysms of the anterior circulation and of the basilar apex is the frontolateral approach as described by Samii, the classical pterional opening being used in MCA aneurysms and for contralateral clipping in the case of multiple aneurysms. A burr hole is placed at the orbitofrontal angle (keyhole), being careful not to open the orbit or the frontal sinus (if it is large enough to reach this point). The craniotome can then be used to complete the flap. Additional burr holes may be needed. In the classical pterional approach, the sphenoid wing should be drilled as close as possible to the anterior cranial fossa. In the event of a tensioned dura, slight elevation of the head and opening the lumbar drainage will result in proper brain

The dura can be opened in a cross-shape or a C shape. We favor the latter, leaving the tip of the convexity upward and at least 2 cm above the sphenoid bone. By

Sylvian valley), or with intravenous diuretics (mannitol or furosemide).

*DOI: http://dx.doi.org/10.5772/intechopen.88038*

aneurysmal clipping.

**5.2 Surgical exposure**

**5.3 Craniotomy**

**5.1 Positioning**

to preserve the anatomical and functional integrity of the normal vasculature, brain parenchyma, and cranial nerves. This not only implies a good proximal control of the arteries but also adequate exposure of the aneurysm and the vessels, beginning with the craniotomy. In the following paragraphs, we describe the key points of aneurysmal clipping.
