Intraoperative carotid bleeding during endoscopic transsphenoidal surgeries is a serious complication associated with high perioperative morbidity and mortality [3,16]. Most bleeding is caused by injury to the arterial wall. There are various methods of bleeding control. Minor bleeding can be stopped by bipolar coagulation, aneurysm clips, vascular sutures, or non-occlusive tamponade. For major injury, occlusion with aneurysm clips or crushed muscle patch is resorted to [6,11,18]. Stenting or complete intravascular occlusion can be resorted to if postoperative angiography reveals pseudoaneurysm or active extravasation. This in turn increases the risk of ischemic complications [17].

Besides a direct injury of the arterial wall, which happens most frequently bleeding from small branches originating from the main trunk of the carotid artery can pose a severe problem as well. One of those arteries is the McConnell’s artery originating from the C4 segment located within the surgical corridor (Fig. 1). Injury to the McConnell’s artery is observed in 30% of endoscopic endonasal approach to the sellar region [5]. It is a rather slim artery that can be easily coagulated by bipolar coagulation if it is within the surgical field. However, its injury within the junction to the carotid artery results in pinpoint and excessive bleeding. When such bleeding occurs, a neurosurgeon needs to act swiftly and decisively. This is complicated by constant pulsatile bleeding in the surgical field obstructing the view, as well as by stress of the surgeon, who does not have much time to think through further surgical tactics. Therefore, it is necessary to have certain knowledge and skills to act in such situations.

A 78-year-old female patient was operated on for asymptomatic planum sphenoidale meningioma. Since the patient had already had a right-sided amaurosis and left optic nerve compression, it was indicated to remove the tumor (Fig. 2). Preoperative planning was performed using Surgical Theater based on thinslice computed tomography (CT) and magnetic resonance imaging image processing. Intraoperative pinpoint bleeding started at the capsular artery junction to the carotid artery trunk in the C4 segment on the left during drilling off the bone of the carotid canal. The arterial wall defect was closed by inserting a small bone fragment into the carotid canal between the arterial wall and the bone (Fig. 3). This way the bone stayed wedged in this position. To avoid dislocation of the bone fragment histoacryl glue was applied (Fig. 3C). The follow-up CT angiography scans did not reveal any pathology in the left carotid artery (Fig. 4A). The patient had no new neurological deficits, and she was successfully discharged from the hospital. The follow-up scans made 3 months later showed no tumor recurrence (Fig. 4B-D) and no pathological changes in the area of the internal carotid artery where the bleeding had occurred (Supplementary Video 1).

Intraoperative carotid artery injury during transsphenoidal surgery is a rare complication that occurs in 0.2-1% of cases [9,12,19]. However, such injuries increase perioperative morbidity and mortality [4,7]. Therefore, it is important not only to recognize and identify risk factors for carotid artery injuries, but also to always be prepared and to act if bleeding occurs.

The best strategy is to prevent carotid artery injury. Preoperative planning is critical. However, it can be sometimes very difficult to prevent arterial injury even for an experienced surgeon [2,3].

Due to the fact that such complications are rare, there is no uniform approach to the management of intraoperative carotid artery injury.

Bleeding occurs most often as a result of arterial injury with forceps or other dissection instruments [15]. Therefore, we prefer gentle drilling of the sphenoidal sinus walls using diamond burs.

The extent of injury and the risks of treatment methods should be evaluated in each case. Only small injuries of less than 3 mm can be closed by bipolar coagulation [6]. It is also possible to stop small bleeding with various hemostatic materials [1,8]. It is not always possible to use aneurysm clips without artery occlusion. Vascular suturing of the arterial wall is complicated in the endoscopic approach and often results in stenosis [10]. Coronary occlusion often results in ischemic complications and greatly increases morbidity and mortality [14].

In the clinical case we have described, we are talking about minor bleeding. However, in this case it was not possible to stop bleeding neither by bipolar coagulation nor with hemostatic materials (Tachosil^®; Takeda, Chuo, Japan). Vascular suturing or using aneurysm clips was also impossible. In order to prevent artery occlusion, we managed to close the defect in the carotid arterial wall by wedging a bone fragment in the carotid canal between the carotid artery and the surrounding bone (Fig. 5) which was acquired from the sphenoid wall during the approach to the pituitary. The fragment was then fixed in place by applying histoacryl glue. That had a good effect. In that case, we prevented possible ischemic complications as a result of carotid artery occlusion.

Given the rapid setting time of histoacryl glue, it can be challenging to apply it accurately in one attempt. Additionally, the glue often hardens within the application tube, necessitating frequent replacements. This limitation is particularly significant when using non-disposable instruments. Furthermore, once histoacryl glue has set, it is difficult to remove. Although in our case there were no problems with application the histoacryl glue, it is necessary to pay close attention to this stage of the surgery. It is best to use a disposable tube for application the histoacryl glue.

We cannot claim that such a method is always effective. However, we can consider that technique using bone fragment and bioglue as one of the surgical options in case of pinpoint carotid bleeding, considering a good bleeding-free outcome in the postoperative period. Due to this event we now routinely preserve small pieces of bone acquired during the approach and histoacryl glue in the operating room, in order to the required material available in the rare case that a bleeding from the carotid artery occurs. Since there have been no literature reports about such a method of controlling intraoperative carotid bleeding, this case may give valuable information to surgeons encountering such a situation and it may be an occasion for further research.

Pinpoint carotid bleeding as a result of intraoperative injury can be stopped by wedging a bone fragment in the carotid canal between the carotid artery and the surrounding bone and fixed it in place by applying histoacryl glue.