**2.1 Eyebrow supraorbital approach (ESA)**

Supraorbital craniotomy with a skin incision through the eyebrow is an anterolateral surgical route that provides access to the aneurysms of the anterior circulation and the upper basilar artery [5, 6, 8–10]. Main indications for ESA:


**Figure 1.**

*Types of minimally invasive approaches. 1 - minipterional, 2 - eyebrow supraorbital, 3 - eyebrow transorbital.*

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

#### **Figure 2.**

*Intraoperative photograph. Schematic representation of the main anatomical landmarks of ESA. Bone borders are marked in black. The skin incision is marked in green. Arrows: white - supraorbital nerve and artery, black branches of the facial nerve, yellow - superficial temporal artery.*


Anatomical landmarks assessed for EAS:


## **2.2 Surgical technique**

The patient was placed in the operating room as for pterional craniotomy (**Figure 3**). Head rotation is carried out depending on the location of the aneurysm:


**Figure 3.** *Position of the patient on the operating table. The head is fixed in a Mayfield clamp, rotated to the contralateral side.*

The zygomatic process is the highest point. This head position provides gravitational retraction of the frontal lobe away from the anterior cranial fossa to facilitate a subfrontal approach. The final position of both the head end and the entire operating table was determined intraoperatively after craniotomy and durotomy and can be changed by rotating the surgical table for better visualization.

### **2.3 Skin incision and soft tissue dissection**

Primarily marked the skin above the eyebrow. The eyebrow was not shaved. For protection of the cornea and sclera, an aseptic ophthalmic gel was placed subconjunctivally. Before the start of the operation, the supraorbital notch was palpated, since it serves as the medial border of the skin incision.

The skin incision was made along the eyebrow, from the level of the supraorbital notch and further within the eyebrow, sometimes extending a few millimetres laterally beyond the hairline (**Figure 4**). The incision planning line is not linear, but somewhat curved (follows the line of the eyebrow) and runs in the mediolateral direction in relation to the hair follicles to avoid postoperative alopecia.

#### **Figure 4.**

*Intraoperative photography. A - Marked skin incision along the eyebrow in ESA. B - the area of the planned incision is infiltrated with an anaesthetic with a vasoconstrictor (optional).*

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

Initially, only the skin was incised. Next, layer-by-layer dissection of fat tissue and the frontalis muscle was performed. The supraorbital nerve and artery, the frontal branch of the facial nerve, and the superficial temporal artery were preserved.

The frontal muscle is cut parallel to the skin incision by monopolar coagulation and then the supraorbital region is skeletonized. The area of bone skeletonization must be at least 3 cm in diameter. The frontal muscle itself was stitched and retracted to the orbit.

After dissection of the frontalis muscle, additional skeletonization of the soft tissues was performed with a raspator, then the frontalis muscle was sutured and retracted to the orbit. Skin tensioners in the amount of three pieces were installed on the upper edge of the wound. The burr hole was placed with a high-speed drill (5 mm) at a key point just below the temporal line above the level of the base of the anterior cranial fossa. The direction of the craniotomy handle is important. To visualize the dura mater, it is necessary to resect with a burr parallel to the anterior cranial fossa, and not towards the orbit. After applying a single burr hole, dissection of the dura within the trefination and careful dissection along the periphery is necessary. To visualize the base of the anterior cranial fossa, as a rule, the inner plate of the bone was resected from the burr hole with a bur or pistol cutters.

The main task in craniotomy is to cut out a bone flap of the required size (at least 2–2.5 cm) with a minimum bone rim, preserve the dura mater, exclude penetration into the frontal sinus and damage to the supraorbital nerve. The first cut was made parallel to the upper edge of the orbit in the medial direction. The second cut was made upward and in a C-shape towards the medial point of the first cut (**Figures 5** and **6**).

If the examination reveals large frontal sinuses, it is necessary to plan osteotomy, avoiding penetration into the latter by lateralizing the approach or choosing an alternative craniotomy. Even though wide sinuses are not a contraindication, but they can increase the risk of cerebrospinal fluid (CSF) rhinorrhea and infectious complications. In some cases, the use of neuronavigation helps to avoid frontal sinus damage (**Figure 7**).

In the case of penetration into the frontal sinus, the tactics depend on the amount of penetration. With a small penetration without damaging the mucous membrane, it is sufficient to coat this area with wax. If the sinus mucosa is damaged, the latter is removed and coagulated, tamponated with muscle or fatty tissue with vancomycin,

#### **Figure 5.**

*Stages of planning the ESA. A - the sequence of cuts in ESA, B - the arrow shows the direction of the cut in the supraorbital region.*

#### **Figure 6.**

*A - incision along the eyebrow, B, C - dissection of soft tissues, transection of the frontalis muscle, D identification of the supraorbital nerve (arrow), E - burr hole in the key point, F,G - view after osteotomy, H - resection of the supraorbital margin with a diamond burr, I – final view after durotomy.*

#### **Figure 7.**

*The use of neuronavigation to assess the topography of the frontal sinus. A, B – 3D model shows the topography of the frontal sinuses, C - through a microscope, the boundaries of the frontal sinuses are visualized.*

and then closed with a periosteal flap. Hermetic closure of the dura mater is extremely important for the prevention of complications.

The bone flap is placed in place and fixed with miniplates (**Figure 8**).

The temporal fascia and muscle were sutured to the periosteum. The subcutaneous tissue and skin were sutured in layers using 4–0 or 5–0 Prolene. Postoperative drainage was not used.

#### **Figure 8.**

*Clinical example of bone flap fixation. A – intraoperative view after fixation with craniofixes, B – postoperative CT scan with reconstruction.*

#### **2.4 Postoperative management**

The early postoperative period includes the management of the patient in the conditions of the neurocritical care unit, usually within 12–24 hours after the intervention. The patient and staff are warned about the possibility of developing periorbital

#### **Figure 9.**

*Clinical case. A – CT Angio – AcomA aneurysm, B – marking of the eyebrow incision, C – intraoperative view after opening the dura mater, D – intraoperative view after dissection of the ACA-AcomA complex, A1 – A2 segments of the ACA, A2 – A2 segment of the ACA, arrow marks the aneurysm neck, E – temporary clipping of A1 segments of the ACA from both sides, F – clipping of the aneurysm neck, G – view before suturing the dura mater, H – postoperative CT angiography, I – craniography with reconstruction, J-view patient one month after surgery.*

oedema, which we observed in all patients. For the purpose of prevention, it is necessary to use ice locally within 1 hour after the operation. Periorbital oedema may persist during the first 2–5 days after the intervention and lead to transient brow ptosis.

We present clinical observations of the use of ESA in different locations of aneurysms.

Clinical example of Acom aneurysm clipping (**Figure 9**).

Man 54 years old. Debut of the disease with a sudden severe headache. Suffering from hypertension, with a rise in blood pressure up to 200/100 mmHg. CT scan of the brain revealed no data for subarachnoid haemorrhage (SAH). CT angiography revealed a saccular aneurysm in the upper PSA region. In the neurological status there are headache, nausea, and severe meningeal syndrome. No focal neurological disorders were identified (**Figure 9**).

Clinical example of Pcom aneurysm clipping (**Figure 10**).

A 75-year-old woman. Onset of the disease with a severe headache, mainly in the occipital region, vomiting. In the neurological status, headache and severe meningeal syndrome. No focal signs.

#### **Figure 10.**

*Clinical example A – CT scan, SAH is visualized in the right Sylvian fissure, B, C – ICA aneurysm at the orifice of the Pcom, D – positioning of the patient with head rotation, E – intraoperative view, the ICA is visualized (1) and blood clots in carotid cistern, E – intraoperative view, arrow shows terminal membrane of the third ventricle and optic nerve (ON), G – dissection of the Sylvian fissure, H – intradural resection of the anterior clinoid process, I – stage of aneurysm clipping, J – intraoperative angiography with indocyanine green, K – view before closure of the DM, L, M – CT angiography and craniography with reconstruction, N – view of the patient 4 weeks after the operation.*
