Traumatic carotid artery dissection and occlusion caused by repetitive mechanical stress to the neck while carrying a mikoshi (portable shrine): illustrative case

Abstract

Background: Traumatic carotid artery dissection can be caused by mechanical stress to the neck. The authors present a case of carotid artery dissection and occlusion caused by repetitive mechanical stress to the neck while carrying a portable shrine (mikoshi) during a traditional Japanese festival.

Observations: A 41-year-old man with no significant medical history developed right hemiparesis and global aphasia while carrying a mikoshi during a festival. Imaging revealed left internal carotid artery occlusion, for which he underwent endovascular treatment. Because the occlusion was caused by dissection, carotid artery stenting was performed. The patient supported the mikoshi's carrying pole by tilting his neck to the left and clamping it between his neck and shoulder. He repeatedly bounced the mikoshi up and down on his left shoulder while carrying it, which likely caused repetitive mechanical stress to the carotid artery, ultimately resulting in dissection and occlusion.

Lessons: Carrying something on the shoulder can cause carotid artery dissection and occlusion. Therefore, care should be taken to avoid placing continuous mechanical stress on the neck while carrying objects. https://thejns.org/doi/10.3171/CASE25488.

Keywords: carotid artery dissection; ischemic stroke; stent; trauma.

FIG. 1.

Imaging findings before endovascular treatment. A: A scene from mikoshi carrying, in which the patient participated, showing other carriers using shoulder padding for neck protection. B:Diffusion-weighted image showing acute ischemic changes in the left MCA territory. The DWI-ASPECTS was 4. C: MR angiogram demonstrating occlusion of the left ICA with preserved blood flow in the horizontal segment of the MCA. D and E: Three-dimensional (D) and axial (E) CT angiograms showing a flap-like structure (arrows) at the origin of the left ICA and the absence of an elongated styloid process.

FIG. 2.

Imaging findings during endovascular treatment. A: Left common carotid artery angiogram showing separation into the true (white asterisk) and false (black asterisk) lumens at the origin of the left ICA. B: Angiogram via the true lumen of the left ICA, showing a complete occlusion of the cervical ICA and a translucent thrombus. C: Angiogram obtained after stent retriever deployment at cervical ICA occlusion, showing severe residual stenosis at the proximal carotid canal and recanalization of intracranial vessels. D: Small amount of retrieved red thrombus. E: Left common carotid artery angiogram showing a persistent occlusion, with separation into the true (white asterisk) and false (black asterisk) lumens at the origin of the left ICA. F: Deployment of the first carotid artery stent (arrowheads) from the petrous segment of the left ICA to the distal portion of the cervical ICA. G: Angiogram obtained after stent deployment, showing recanalization of the left ICA with mild residual stenosis in the cervical ICA and expansion of the proximal carotid canal. H: Deployment of a second carotid artery stent overlapping the first carotid artery stent. The extent of the two stents is marked by arrowheads. I:Left common carotid artery angiogram showing persistent contrast entry into the false lumen at the origin of the left ICA (arrows). J: A third carotid artery stent is deployed proximally, overlapping the second carotid artery stent. The extent of all three stents is marked by arrowheads. K: Final left common carotid artery angiogram showing minimal residual contrast entry into the false lumen (arrows), with good expansion of the cervical ICA. L:No evidence of embolic complications was observed in the left ICA and MCA.

FIG. 3.

Imaging findings after endovascular treatment. A: Diffusion-weighted image obtained on postoperative day 1, showing no expansion of the infarct area. B: MR angiogram showing recanalization of the left ICA. C: Sagittal CT reconstruction angiogram showing good patency of the stents from the carotid canal to the cervical ICA, with no visible false lumen.

FIG. 4.

Schematic illustration of mechanical stress to the neck during mikoshi carrying. A and B: Reconstructed (A) and coronal (B) CT angiograms obtained after stenting. The arrowhead indicates the proximal end of the overlapping carotid artery stents. The double-headed arrow indicates the distance (6 cm) from the left shoulder to the suspected entry site of dissection. C: Simulation using a 6-cm-wide block representing the mikoshi pole placed on the left shoulder without neck tilting. No direct pressure (red arrows) is applied to the neck. The white arrow indicates the suspected entry point of dissection. D: Simulation replicating the patient’s actual posture, with neck tilted to the left. Direct mechanical stress (red arrows) is transmitted from the simulated pole to the carotid artery at the height corresponding to the entry point of dissection.