**3.2 Surgical technique**

The patient is positioned like for pterional approach. An arcuate incision of the skin and soft tissues of 4–5 cm was performed within the scalp. In the temporal region, the incision was started 1–1.5 cm above the zygomatic process and anteriorly from the superficial temporal artery and continued anteriorly to the projection of the superior temporal line (**Figure 12**).

The incision of the superficial fascia and temporalis muscle was carried out in a C-shaped manner with the base towards the pterion. After subperiosteal dissection, the temporalis muscle was brought together using hook tensioners. This allows the pterion area to be completely exposed. The burr hole was placed upwards from the

#### **Figure 11.**

*Intraoperative photography. Schematic representation of the main anatomical landmarks of MPA. Bone borders are marked in black. Skin incision marked in green. Arrows: white - supraorbital nerve and artery, red - branches of the frontal branch of the facial nerve, blue - superficial temporal artery.*

**Figure 12.** *Intraoperative photography. A, B - Skin incision marked for MPA.*

fronto-zygomatic suture immediately below the superior temporal line. A 2–3 cm craniotomy includes the lateral portions of the sphenoid bone, part of the frontal bone below the superior temporal line, and a minimal portion of the temporal bone. As in the case of classical pterional approach, the crest of the sphenoid bone was resected with cutters and a bur until the meningoorbital artery was visualized in the superior orbital fissure (**Figure 13**).

The durotomy was performed with a semi-oval incision with the base towards the pterion. After opening the dura mater, the Sylvian fissure was visualized in the centre of the wound, which indicates the correct location of the craniotomy. The intradural stage of surgery was performed under microscopic magnification using traditional microneurosurgical techniques.

After clipping of the aneurysm and verification of its complete exclusion, hemostasis was performed. The dura mater was sutured hermetically. In order to prevent pneumocephalus, the subdural space was irrigated with saline until a distinct brain pulsation appeared and air was forced out. The bone flap was fixed with craniofixes or miniplates. The temporal fascia/muscle, subcutaneous tissue, and skin were sutured in layers (**Figure 14**).

Subcutaneous drainage was not performed due to the small size of craniotomy. Postoperative management is identical to the management of patients after ESA.

Clinical example of MCA aneurysm clipping (**Figure 15**).

#### **Figure 13.**

*Intraoperative photos, MPA on the right. A – intraoperative view, skin-aponeurotic flap and temporal muscle are reduced anteriorly, B – burr hole is placed in the area of the pterion, C – bone flap is sawn out, D – view after craniotomy.*

*Keyhole Microsurgery for Cerebral Aneurysms DOI: http://dx.doi.org/10.5772/intechopen.110396*

#### **Figure 14.**

*Intraoperative photographs. A - the bone flap is put in place and fixed, B,C - sutures on the temporal muscle and skin, D,E,F - CT and craniography.*

#### **Figure 15.**

*A - marking of the planned incision, B - CT angiography - saccular aneurysm M1 of the segment of the MCA on the left, C - intraoperative view after minipterional craniotomy and opening of the dura, the centre of craniotomy over the Sylvian fissure, D - saccular aneurysm M1 of the segment of the MCA, E - clipping of the aneurysm, F – intraoperative angiography with indocyanine green, aneurysm is excluded from the cerebral circulation, MCA branches are visualized, G – craniography and CT after surgery, H – view of the patient a week after surgery.*

A 62-year-old woman with unruptured MCA aneurysm. Clinical example of ophthalmic aneurysm clipping (**Figure 16**). A 30-year-old woman with unruptured ophthalmic artery aneurysm.

#### **Figure 16.**

*A - marking of the planned incision, B - CT angiography - carotid-ophthalmic aneurysm is visualized on the right, C - intraoperative view after MPA and opening of the dura, the Sylvian fissure is marked with an arrow, D - intradural resection of the ACP with a 2-mm diamond burr E – aneurysm lateral to the optic nerve, F –clipping of the aneurysm, G – postoperative CT, H – view of the patient 2 weeks after surgery.*
