“Mickey Mouse head aneurysms”-kissing aneurysms of the distal anterior cerebral artery: a case report and literature review

Open access: https://ina-jns.org/ “Mickey Mouse head aneurysms” kissing aneurysms of the distal anterior cerebral artery: a case report and literature review Sachin Chemate1*, K. Chandrasekar2, Shankar Ganesh C. V.2, Chetana Govindaraju1, M. Balamurugan2 Background: When two or more adjacent intracranial aneurysms arises from same or different arteries with separate origins and partially adherent walls is referred as “Kissing aneurysm”. These are rare aneurysms1. Among different locations of kissing aneurysms reported in the literature, kissing aneurysms of bilateral distal anterior cerebral arteries (DACA) two different aneurysms situated symmetrically on opposite DACA are very rare. Case Description: 69 years old lady with multiple comorbidities was admitted with anterior inter-hemispheric bleed, Magnetic Resonance Angiography (MRA) and Digital Subtraction Angiography (DSA) showed ruptured bilateral DACA aneurysms in mirror position to each other forming a Mickey Mouse head appearance. Patient was managed surgically by craniotomy and clipping of both


INTRODUCTION:
'Kissing' aneurysms were initially defined and described by Jefferson 1 in 1978. When two or more adjacent Intracranial aneurysms arises from same or different arteries with separate origins and partially adherent walls is referred as "Kissing aneurysm". 1 They occur in <1% of all intracranial aneurysms. 2 The most common site is the internal carotid artery (ICA) followed by the anterior communicating artery (ACom), distal anterior cerebral artery (ACA), and fenestrated basilar artery (BA). 2-8 Kissing aneurysms of bilateral distal anterior cerebral arteries (DACA) are rare and till date only 12 cases reports have been reported. We report one such case which was managed surgically by craniotomy and clipping of both aneurysms.

CASE REPORT
69 years old lady was admitted to emergency department with complaints of one episode of sudden loss of consciousness lasting for 5-10 minutes, followed by headache. She was known case of type II diabetes mellitus since 15 years and systemic hypertension since 10 years on regular management and previous history of well differentiated squamous cell carcinoma of oesophagus diagnosed 5 years ago for which she underwent radiation and achieved remission. On examination, the patient was E4V4M6, vitals were stable, pupil was normal sized and reacting to light, and there were no focal neurological deficits. Due to previous history of carcinoma oesophagus and patient's history, cerebral metastasis was suspected and MRI brain was done but surprisingly it showed anterior interhemispheric bleed with corpus callosum hematoma (Figure 1a and 1b) and Magnetic resonance angiography (MRA) of the brain was suggestive of two adjacent aneurysm on bilateral distal anterior cerebral artery (ACA) at the junction of pericallosal and callosomarginal arteries (Figure 2a and d). Digital subtraction angiography (DSA) was done which showed two adjacent aneurysms over each DACA at the junction of pericallosal and callosomarginal arteries. Right side aneurysm was size 9.4 × 8.7 mm with a neck measuring 2.5 mm with a daughter lobule and superiorly projecting rupture site. Left-sided aneurysm measured size 7.6 × 5.5 mm with a neck of 2.5 mm. Both were directed antero-superiorly. Both A1 ACAs were of the same size with good

CASE REPORT
crossflow. Focal areas of segmental spasm were noted in right pericallosal arteries (Figure 3a-d).
The patient underwent surgery; right frontal craniotomy was done. Anterior interhemispheric approach was utilized. With help of navigation (Figure 4), pericallosal and callosomarginal arteries of the left side was identified and traced proximally. Right DACA aneurysm arising from the junction of pericallosal and callosomarginal artery directing anterosuperiorly was visualized (Figure 5a and 5b). Temporary proximal clip was applied over right A2 and right DACA aneurysm was clipped. Left DACA aneurysm was identified, it was buried in the brain parenchyma with overlying hematoma and adhesions. Proximal control over right A2 achieved with temporary clip. While dissecting dome of aneurysm there was intraoperative rupture, which was managed with bipolar cautery and permanent clip applied at the neck of right DACA aneurysm. Intraoperative Indocynine Green (ICG) dye showed patent proximal and distal DACA, both the aneurysms were completely secured and there was no residual neck ( Figure 5c). Minimal brain retraction was used. Postoperatively, patient was extubated immediately. Postoperatively patient had no new deficit. As our institutional protocol, patient was managed with triple-H therapy. CT brain was done on postoperative day 1, which showed no evidence of infarct or haemorrhage (Figure 6a and 6b). Patient was discharged on postoperative day day 7 without any neurological deficit.

DISCUSSION:
Epidemiology DACA aneurysms have been reported to have an average incidence of 4.4%. 14 Bilateral DACA "mirror image aneurysms" are extremely rare 9-21 , with majority of reports from Japanese literature ( Table 1).

Pathophysiology
Laitenen and Snellman 22 postulated that a supreme anterior communicating artery, a bridging artery located at the bifurcation of A2 into the pericallosal and callosomarginal arteries and other embryological connections like Azygos ACA, and triple ACAs might represent an embryological remnant and lead to flow disturbance in anterior cerebral artery bifurctation causing bilateral, symmetrical aneurysms. However, no vascular anomaly was detected in our case. Yasargil and Carter 23,24 treated 13 patients with DACA aneurysms with microsurgical techniques and found that in there were two cases where the aneurysmal sacs were connected. Based on this they suggested that, some   Although MRA is very sensitive and specific for distal aneurysm and 3D-reconstructions are also available in this imaging, however, DSA provides complete study of intracranial vessels in real time. Vasospasm can also be diagnosed during angiogram in early phases. Other distal Incidental aneurysms can be seen in angiograms. It also gives very critical information regarding aneurysm location, shape, size of neck, branch vessel, and cross circulation; which helps surgeon to decide whether to go for clipping or coiling.

Management
The most definite management at the bilateral DACA aneurysm is clipping the aneurysm. Bilateral DACA aneurysm has tendency to rupture so it presents with subarachnoid haemorrhage and anterior interhemispheric hematoma. Incidence of rebleed is also very high in DACA aneurysm. Through anterior interhemispheric approach we can not only achieve a proximal control on A2 and secure the aneurysm but also it provides an access evacuation of for hematoma and mass effect and thorough washing of cranial cavity with normal saline during surgery also removes blood by products which decreases the intensity and duration of vasospasm. Aneurysm occlusion rate is very high with clipping and rebleeding or recurrence is very rare after clipping. Challenges of craniotomy and clipping are narrow working corridor, edematous brain, adhesions and buried dome of aneurysm in the surrounding brain parenchyma. Dome of the aneurysms is always directed towards the surgeon and proximal A2 is inferior to aneurysm when visualised from working corridor, hence proximal

DIAGNOSIS
CT angiography, MRA, and DSA are most useful control is challenge and chance of intraoperative rupture is high. Only one case report is available in literature about the experience of coiling. Our patient was taken up for clipping after angiogram. During the operative procedure, retraction was applied first on the right medial frontal lobe. Parent artery and dome of left aneurysm was identified. Dome was followed inferiorly up to the neck and the clip was applied on proximal A2. After securing left-sided aneurysm completely, right-sided A2 proximal clip was applied. Dome and neck of the right DACA aneurysm was then dissected and clip applied. However while dissecting the aneurysm aneurysm ruptured in spite of temporary clip on proximal A2. Recurrent use of temporary clips loses there occlusion force resulting in only partial occlusion. Intraoperative rupture was managed with bipolar cautery over dome and multiple clipping over the bleb. After securing the bleb rupture, final clip was applied at the neck.

CONCLUSION
DSA is essential for diagnosis of multiple intracranial aneurysm. Mirror images of bilateral DACA aneurysms are very rare. They are specific type of aneurysms with probably derived from embryological rearmament. Basic surgical strategy of securing the parent artery and clipping the neck after meticulous dissection of each aneurysm separately is key for successful clipping of aneurysm, as chance of intraoperative rupture is very high.

CONFLICT OF INTEREST
There are no conflicts of interest.

FINANCIAL SUPPORT AND SPONSOR-SHIP
There is no funding available for this case report.

AUTHORS CONTRIBUTIONS
All authors equally contributed immensely.