Keyhole Microsurgery for Cerebral Aneurysms

Abstract

The choice of an effective and safe surgical approach is an important and largely outcome-determining step in the microsurgical treatment of cerebral aneurysms. Transcranial approach to aneurysm should provide proximal and distal control, visualization of the aneurysm and surrounding structures, freedom to work with microinstruments, optimal and close view of the surgical field with the necessary ergonomics and the possibility of comfortable work for the neurosurgeon. In addition, the approach should provide a low risk of associated complications, good cosmetic outcomes and patient satisfaction. Today, a neurosurgeon has a sufficient number of approaches to cerebral aneurysms. Minimally invasive approaches are the reduced model of traditional approaches and each of these approaches has a specific surgical corridor that cannot be changed during microsurgical manipulations, unless through the transition to an extended craniotomy.

1. Introduction

The rapid development of minimally invasive neurosurgery is associated with the wide availability and distribution of highly informative neuroimaging technologies. Neurosurgeons often face the problem of choosing the most optimal treatment method in search of minimizing surgical aggression. For several decades, in the surgical treatment of aneurysms, pterional craniotomy has been the traditional approach for most aneurysms of the anterior parts of the cerebral arterial circle and the upper parts of the basilar artery [1]. However, upon critical analysis, it becomes clear that the “collateral damage” of tissues during craniotomy is not related to the immediate goal of the surgical intervention. These negative consequences affect the immediate and long-term recovery of patients and prolonged hospitalization, which leads to long-term disability and, accordingly, economic costs.

The popularization of the concept of “keyhole” surgery is associated with the possibility of accurate preoperative planning, improvement of microneurosurgical techniques, intraoperative control in the form of fluorescein angiography, video endoscopic assistance and neurophysiological monitoring, which allows focusing on the accuracy, efficiency, and safety of surgical intervention. It is important that minimally invasive approaches make it possible to minimize iatrogenic trauma by creating an individual surgical corridor. The principle of “individual” access to cerebral aneurysms is reduced to the use of several minimally invasive approaches depending on the specific neuroimaging pattern in comparison with the previously used algorithm and the choice of pterional craniotomy for all aneurysms of the anterior cerebral arterial circle [2, 3, 4, 5, 6, 7].

The modern concept of microsurgical treatment of cerebral aneurysms involves the choice of an individual approach. The main goal of individualization is to create the shortest efficient route to the target with minimal collateral damage, ensuring the safety of the intervention. Individualized minimally invasive approach in the microsurgical treatment of cerebral aneurysms improves surgical and clinical outcomes, reduces the time of surgery, length of stay in the hospital, and the cost of treatment and provides excellent cosmetic results [4, 6, 7].

The three keyhole approaches are discussed below: eyebrow supraorbital, minipterional and transorbitals.

2. Types of keyhole approaches

Minimally invasive approaches are reduced models of traditional craniotomies: pterional, supraorbital, orbitozygomatic, etc. (Figure 1).

Figure 1.

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

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, 9, 10]. Main indications for ESA:

• Anterior circulation aneurysms

• Internal carotid artery (ICA)

• Anterior cerebral artery (ACA) A1-A2 segments

• Anterior communicating artery (Acom)

• Middle cerebral artery (MCA) M1 segment-M2 segments (if M1 segment is not more than 20 mm)

Anatomical landmarks assessed for EAS:

• supraorbital notch,

• superior margin of the orbit,

• and superior temporal line,

• the topography of the frontal sinuses is preliminarily assessed based on neuroimaging data (Figure 2).

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.

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:

• 15° for ipsilateral Sylvian fissure, MCA aneurysms

• 20–30° for ICA

• 40–60° for Acom aneurysms

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).

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).

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.

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).

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.

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, 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).

Figure 8.

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

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.

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 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).

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.

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).

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.

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.

3. Minipterional approach

Minipterional approach (MPA) is a limited model of pterional approach, the centre of which is the Sylvian fissure [11, 12, 13]. Therefore, the main indications for MPA are patients with MCA and ICA aneurysms. MPA can be an alternative to minimally invasive anterolateral approaches for patients with large frontal sinuses.

3.1 Anatomical access landmarks

Pterion is one of the key landmarks of the MPA and the area of the burr hole placement (Figure 11). It is localized in the region of the temporal fossa and is a point at the junction of the parietal bone, the squamous part of the temporal bone, the greater wing of the sphenoid bone and the frontal bone. These bones in the region of the pterion are connected with a sphenoparietal, coronary and squamous suture. Immediately below the pterion, the anterior Sylvian point is located. This landmark is the most common for entry and further dissection of the Sylvian fissure, since the cistern of the Sylvian fissure is usually dilated in this area.

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.

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).

Figure 12.

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

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 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).

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.

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).

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.

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 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).

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.

A 30-year-old woman with unruptured ophthalmic artery aneurysm.

4. Transorbital approaches

Transorbital approaches, due to the inclusion of the upper wall of the orbit in the bone flap, increase the free space for working with microinstruments, significantly reduce the distance to the target of surgery, and reduce brain retraction. This made it possible to expand indications in aneurysm surgery, for example, to use this approach for large and giant aneurysms, small unruptured basilar aneurysms. The main modifications of transorbital approaches include:

1. Eyebrow transorbital approach (ETA)

2. Transpalpebral transorbital approach (TPTA)

Despite different types of skin incisions, the stage of osteotomy is identical, but the functional and cosmetic outcomes are significantly different (Figure 17).

Figure 17.

Various types of skin incisions for transorbital craniotomy. A - eyebrow (blue), B - transpalpebral (red).

4.1 Eyebrow transorbital approach

The skin incision was made along the eyebrow in accordance with the described guidelines for ESA. The planning of transorbital approach is identical to ESA and requires a thorough assessment of the topography of the frontal sinuses [14, 15]. With a high risk of penetration of the frontal sinus, the choice of lateralization of the bone window or the choice of a traditional approach will be correct.

Indications for ETA:

• Aneurysms of the anterior circulation: ICA, Acom, A1 segment of ACA, MCA of M1-M2 segments, excluding distal ones.

• Small unruptured upper basilar artery aneurysm

• Anatomical access landmarks are shown in Figure 18.

Figure 18.

Intraoperative photo. Schematic representation of the main anatomical landmarks of access. Bone borders are marked in black. The skin incision is marked in green. Branches of the superficial temporal artery are marked in red. Arrows: white - supraorbital nerve and artery, blue - frontal branch of the facial nerve.

4.1.1 Surgical technique

Patient positioning and head rotation are identical to those for pterional craniotomy and depends on aneurysm location. For all transorbital approaches, a temporary tarsorrhaphy was necessarily performed with preliminary placement of an antiseptic gel subconjunctivally. A skin incision was made directly along the eyebrow, starting from the level of the pupillary line and continuing laterally within the eyebrow, sometimes extending several millimetres laterally. The supraorbital nerve and artery, the frontal branch of the facial nerve, and the superficial temporal artery are always preserved. The initial stage of incision and dissection of the frontalis muscle is identical to that in ESA, however, after transection of the frontalis muscle, careful skeletonization of the upper edge of the orbit was performed from the level of the supraorbital foramen to the fronto-zygomatic suture. Dissection of the contents of the orbit lateral to the fronto-zygomatic suture should be avoided due to the risk of damage to the lateral canthal ligament and impaired movement of the upper eyelid with the formation of a temporary or permanent diastasis when the eyelids is closed. During dissection, special attention was paid to the preservation of the periosteum and periorbital tissue. The temporal muscle was separated from its place of attachment at the level of the superior temporal line and brought down with a retractor towards the temporal fossa (Figure 19).

Figure 19.

Intraoperative view, A, B – soft tissue incision along the eyebrow, C – subperiosteal dissection of the supraorbital region of the frontal bone, the edge of the orbit and the zygomatic process of the frontal bone.

A single burr hole was made downward from the temporal line immediately above the level of the base of the anterior cranial fossa, at the key point. The transorbital approach included the roof of the orbit, a portion of the frontal bone, and approximately 1–1.5 cm of the zygomatic bone. A single bone flap was sawn out using a craniotome and a high-speed burr. The diameter of the bone window is approximately 25–30 mm. The first cut was made from the burr hole upwards in the supraorbital region, describing a C-shaped bend towards the upper wall of the orbit. From the side of the orbit, the contents of which are protected with a spatula, a cut was also made using a craniotome towards the line of the previous cut. In the area of the zygomatic process, sawing towards the key point can be carried out both with a craniotome and with an oscillating saw, using the protection of the contents of the orbit with a spatula. The roof of the orbit was broken using a chisel. After osteotomy, sharp edges were resected in the area of the upper wall of the orbit with a bur and wire cutters (Figure 20).

Figure 20.

Planning and stages of ETA. A – the sequence of cuts (the arrow indicates the key hole from which the upper wall of the orbit is broken with a chisel), B – the burr hole is placed at the key point and the bone is cut away from the supraorbital hole towards the key point, C – view of the bone flap, D – performed transorbital access, frontal sinus opened.

If necessary, extradural resection of the sphenoid bone and anterior clinoid process performed the degree of bony resection depends on the location and size of the aneurysm. All manipulations were performed through minimal craniotomy. Upon completion of the necessary resection of the bone structures, the dura mater was opened with a semi-oval incision with the base towards the orbit. Then, the surgical technique is dictated by the location and size of the aneurysm.

Classical microsurgical technique is used. Wound closure is standard and has been described above (Figure 21).

Figure 21.

Intraoperative view. A - The bone flap is put in place and fixed with miniplates. B – CT craniography after minitransorbital craniotomy.

4.2 Transpalpebral transorbital approach

The transpalpebral approach, or access through the upper eyelid, is borrowed from ophthalmic and plastic surgery. Transpalpebral approach has been used in neurosurgical practice since 2008 and includes an incision along the natural crease of the upper eyelid followed by a minimal fronto-orbital craniotomy [16, 17, 18]. In fact, the TPTA trajectory is identical to the ESA and ETA and provides access to the anterior cranial fossa, the parasellar space.

The indications for TPTA are identical to those for ETA.

4.2.1 Anatomical access landmarks

Knowledge of anatomy is an indispensable condition for ensuring the effectiveness and safety of surgical intervention. Anatomical landmarks are similar to ETA (Figure 22).

Figure 22.

Intraoperative view. Schematic representation of the main anatomical landmarks of access. Bone borders are marked in black. Arrows: white - supraorbital nerve and artery, grey - circular muscle of the eye, black - lateral cantal ligament, red - temporalis muscle with branches of the frontal branch of the facial nerve.

4.2.2 Surgical technique

The eyebrow and eyelid area are prepped with antiseptic solutions, an ophthalmic gel was applied subconjunctivally. Next, a temporary tarsorrhaphy was performed with a 5–0 thread. The planned incision area was infiltrated with an anaesthetic solution and a vasoconstrictor. The incision was made along the natural fold of the upper eyelid from the level of the supraorbital opening 3.5–4 cm long. If necessary, the incision can be extended laterally by several millimetres exclusively within the fold. The incision should start at least 10 mm above the upper edge of the eyelid and at least 5–6 mm above the projection of the lateral canthal ligament. Thus, the incision is planned below the supraorbital and frontotemporal branches of the facial nerve, which makes it possible to exclude negative cosmetic consequences associated with nerve damage. Initially, the incision was made through the skin and the orbicular muscle of the eye while maintaining the orbital septum. Damage to the orbicularis muscle must be minimized as the blood supply to the eyelid passes through the orbicularis muscle. A single musculoskeletal flap was formed, which ensures adequate healing. Dissection by the sharp way was carried out mainly in the upper and lateral direction. At this stage, the upper and lateral edges of the orbit were palpated for control. Next, a subperiosteal dissection of the supraorbital region, the upper lateral edge of the orbit, and the zygomatic process of the frontal bone was performed with visualization of the fronto-zygomatic suture. During dissection, special attention was paid to the preservation of the periosteum and periorbital tissue. The temporalis muscle was dissected by monopolar coagulation from the place of its attachment at the level of the superior temporal line. Limitation of muscle dissection, its dissection and devascularization eliminates the formation of a depression in this area.

A minimal orbitofrontal craniotomy included the roof of the orbit, a portion of the frontal bone, and approximately 1–1.5 cm of the frontal process of the zygomatic bone. A single bone flap was sawn out using a craniotome and a high-speed burr. The diameter of the bone defect was no more than 25–30 mm. After craniotomy, the roof of the orbit was broken using a chisel. If necessary, extradural resection of the anterior clinoid process and decompression of the optic nerve canal were performed from this access. When opening the frontal sinus, the defect was closed according to the previously described principles. The dura mater was opened with a semi-oval incision with the base towards the orbit. Additionally, tension sutures were placed on the edges of the dura mater to increase the viewing angle and epidural hemostasis (Figure 23).

Figure 23.

Intraoperative view, A – soft tissue incision along the natural crease of the upper eyelid, B – mobilization of the upper wall of the orbit, C – dissection of a part of the temporal muscle over the area of application of the burr hole, D – burr hole is applied at a key point, E – propyl in the area of the frontal process of the zygomatic bones, above the fronto-zygomatic suture. E – cut in the region of the upper wall of the orbit, medial to the supraorbital notch, G – using a chisel, the upper wall of the orbit is broken, H – view after craniotomy, I – the dura mater is opened with the base to the orbit.

At the end of the intervention, the bone flap was fixed with miniplates. The wound was sutured in three layers: muscle, subcutaneous tissue and skin. The temporalis muscle can be fixed to miniplates or to holes formed in the area of the upper lateral wall of the orbit. The orbicular muscle of the eye was sutured with a 4–0 absorbable suture. An intradermal suture was applied using a 5–0 or 6–0 suture. Postoperative drainage was not used.

Clinical example of ophthalmic aneurysm clipping through ETA (Figure 24).

Figure 24.

Clinical example of clipping of multiple ETA aneurysms. A –CT angiography, B- intraoperative view, position of the patient on the table, incision marking; C – view after opening the dura mater; D – intraoperative view after dissection and clipping of the ICA bifurcation aneurysm; ICA, E – dissection of the aneurysm (An) of the MCA bifurcation with visualization of the M1 and M2 branches of the MCA, G – view after clipping of the aneurysm, H – view of the patient 1 month after surgery, I, J – postoperative CT craniography with reconstruction, CT angiography.

A 58-year-old woman with multiple unruptured aneurysm: ICA terminus and MCA artery aneurysms.

Clinical example of basilar bifurcation aneurysm clipping through TPTA (Figure 25).

Figure 25.

Clinical example. A – CT angiography, basilar artery aneurysm, B – Intraoperative view of planning a skin incision along the natural fold of the upper eyelid on the right, C – intraoperative view through the retrocarotid space: 1 – ICA, 2 – aneurysm, 3 – PCA P1 segment, D – view through the retrocarotid space: 1 – optic nerve, 2 - ICA, 3 - Aneurysm, 4 – posterior cerebral artery (PCA), P1 segment on the left, E - view through the endoscope 0°: 1 - PCA, 2 - Pecheron artery, C - clivus, 3n - oculomotor nerve, A - aneurysm, E – view through the 0° endoscope. After clipping: 1 - PCA, 2 – superior cerebellar artery, 3 - Pecheron artery, P - pons, G - control of CT angiography - a clip is visualized. H - during bone reconstruction, the volume of the craniotomy is visualized, I - is the view of the patient after 2 months.

A 53-year-old woman unruptured basilar bifurcation artery aneurysm.

5. Conclusion

In summary, it should be noted that the surgical approach is an important stage of the entire intervention, which can determine the outcomes of patients. Today, highly informative neuroimaging, coupled with modern neurosurgical microscopes, endoscopy and microinstrumentation, substantiate a completely different approach to the surgical treatment of cerebral aneurysms, an approach that is based on individual anatomy: facial, bone, and vascular. An approach that provides a choice between a traditional approach, a minimally invasive approach, or the use of the endovascular intervention. The main task of a neurosurgeon is the correct choice of treatment method depending on the individual neuroimaging pattern and the patient’s condition. The main goal of individualization is to create the shortest efficient route to the target with minimal collateral damage, ensuring the safety of the intervention. Sufficient experience in microsurgical aneurysm clipping and proper selection of patients allows us to use different minimally invasive approaches safely and effectively.

Conflict of interest

The authors declare no conflict of interest.

Consent of patients

All of patients gave their consent to the publication of their photos in this article.