A 46-year-old patient was admitted to the clinic of the Scientific Research Institute – Regional Clinical Hospital No. 1 named after Prof. S. V. Ochapovsky on March 13, 2025. The patient complained of periodic headaches that had been bothering him for the past six months. An outpatient magnetic resonance imaging scan of the brain revealed an aneurysm of the right ICA. The patient was hospitalized for digital subtraction cerebral angiography and surgical treatment. On examination: the neurological status without focal neurological symptoms, the somatic status without abnormalities. Computed tomography angiography and cerebral angiography verified a saccular aneurysm of the right ophthalmic artery measuring 4.0×3.9 mm with a neck of 3.3 mm (Fig. 1A–D).

After consultation with endovascular surgeons, the patient was offered a choice: endovascular treatment using an intracranial stent or open aneurysm exclusion. The potential risks of open and endovascular treatment were explained. The patient preferred open surgery and signed the relevant consent form.

The operation was performed on March 18, 2025. A limited incision of the dura mater was made using the standard pterional approach. The cistern of the lateral cerebral fossa (Sylvian cistern) was opened to relax the brain. An extradural subfrontal approach was used to resect the lesser wing of the sphenoid bone and remove the anterior clinoid process. Hemostasis was achieved. After the final opening of the dura mater and dissection of the basal cisterns, the optic nerve, ICA, and aneurysm dome were identified.

An extradural subtemporal approach to the anterior surface of the temporal bone pyramid was performed to ensure proximal control of possible bleeding. The foramen spinosum and foramen ovale were identified. Partial peeling of the outer wall of the cavernous sinus was performed, exposing the mandibular nerve. The greater petrosal nerve was identified.

After skeletonization of the apex of the petrous bone and trepanation of the upper wall of the carotid canal (Fig. 2A), mobilization and temporary clipping of the petrosal segment of the ICA were performed (Fig. 2B). Then the distal dural ring was dissected, the dome and neck of the aneurysm were exposed (Fig. 2C). Clipping of the aneurysm of the right ophthalmic artery was performed (Fig. 2D). After checking the patency of the ophthalmic artery, coagulation of the aneurysm dome was performed. The temporary clip from the ICA was removed, hemostasis was achieved in the area of the petrous segment of the ICA, and the surgical wound was sutured. A video of the operation is available at the link: https://youtu.be/EoHpNJ5TgcA.

The postoperative period was uneventful, with no increase in neurological symptoms. Follow-up computed tomography and сomputed tomography angiography scans performed one day after surgery (March 19, 2025) revealed no residual aneurysm (Fig. 3A–C). The wound healed by primary tension, the sutures were removed on the 9th day, and the patient was discharged for outpatient follow-up with a recommendation to check the radicality of clipping in 6 months.

Performing open surgeries on cerebral aneurysms is associated with an increased risk of intraoperative bleeding during dissection of the aneurysm dome and neck [8].

Patients with ophthalmic artery aneurysms, which are anatomically complex and difficult to access for surgery, are operated on mostly using intravascular methods. These include occlusion using microcoils: balloon and stent assistance, as well as the installation of flow-diverting devices [9–11].

In open surgery, prevention and control of bleeding from intradural and transit aneurysms of the ophthalmic segment of the ICA are particularly important, since routine application of temporary clips proximal to the aneurysm is impossible due to anatomical conditions. To date, the main method for controlling bleeding from ophthalmic aneurysms remains the exposure of the bifurcation of the common carotid artery into the internal and external branches in the neck. This method of proximal control involves the use of a second surgical approach with possible complications: paresis of the vocal cords and tongue; hematoma in the surgical area, causing compression of the trachea and severe breathing difficulties, in some cases requiring intubation or tracheostomy; dissection of the exposed arteries. Access to the neck vessels may be difficult or impossible in the presence of cicatricial adhesive process after previous surgery or radiation therapy [4].

Occlusion of the ICA in the neck often does not lead to complete cessation of antegrade blood flow through the ophthalmic segment, which is associated with the presence of distal anastomoses between the ICA and branches of other brachiocephalic arteries [12].

Methods for mobilizing the ICA proximal to its cerebral portion, in the ICA carotid canal, were proposed quite some time ago [6][7], but they did not become widely used due to the complexity of their technical implementation and the presence of a number of shortcomings. The intradural access to the petrosal part of the ICA proposed by T.M. Wascher et al. [6], involved complete mobilization of the temporal lobe pole, which significantly increased the risk of developing venous cerebral infarction in the surgical area, and the use of a balloon catheter for occlusion of the ICA carried the risks of incomplete occlusion or excessive compression, leading to damage to the arterial wall.

In the technique described by L.N. Sekhar et al. [7], orbitomaxillofacial craniotomy was proposed for the isolation of the petrosal segment of the ICA, which made the operation more traumatic and worsened cosmetic results. In addition, in all cases, when drilling the carotid canal in the posterolateral triangle (Glasscock triangle) required opening the bony part of the auditory tube, which increased the risk of developing inflammation of the middle ear inflammation and hearing loss. Both techniques involved transection of the greater petrosal nerve, creating a potential risk of complications due to denervation of the lacrimal gland on the access side.

In the described case, a modified method of proximal bleeding control was used (video) [5]. To perform this procedure, after standard pterional craniotomy, the upper wall of the carotid canal in the posteromedial triangle (Kawase triangle) is resected using an extradural approach. The roots of the trigeminal and greater petrosal nerves are preserved; the Eustachian tube, cochlea, and internal auditory canal remain intact. The ICA is mobilized in a sheath of periosteum lining the walls of the carotid canal, which minimizes its trauma, and occlusion of the ICA with clips with a specified degree of compression of their branches reliably stops blood flow without damaging the vascular wall.

The use of modern methods of proximal bleeding control during open surgery in patients with aneurysms of the ophthalmic segment of the ICA, including temporary clipping of the petrosal segment of the ICA, allows for the optimization of surgical technique. This results in increasing the safety of the intervention due to the reliable prevention of bleeding, as well as minimizing the amount of tissue trauma, and improving cosmetic and functional outcomes. All of these factors are important for the patient’s quality of life.

Vyacheslav V. Tkachev performed the surgery, made the main contribution to the concept and design of the article, and supervised the writing and editing process. Dmitry V. Litvinenko, Arkady D. Fedorenko participated in the development of the concept and design of the article, writing and editing the text, as well as preparing illustrations and video. Irina N. Sever participated in the analysis of literature data, processing of illustrations and video, editing the text. All authors approved the final version of the article.

Compliance with ethical standards. Consent statement. The patient consented to the publication of the article “Exposure of the petrous segment of the internal carotid artery as a method for prevention of intraoperative bleeding during clipping of carotid-ophthalmic aneurysms: a clinical case” in the “Sechenov Medical Journal”.

Conflict of interests. The authors declare that there is no conflict of interests.

Financing. The study was not sponsored (own resources).