PMC10408648_01
Initial imaging findings. (a) Axial computed tomography image showing thick traumatic subarachnoid hemorrhage. (b) Computed tomography angiography image showing no suspicious vascular abnormalities.
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F1
Head computed tomography (CT) revealed thick subarachnoid hemorrhage (SAH) in the right Sylvian fissure [Figure 1a]. Therefore, we performed head CT angiography (CTA), but no suspicious vascular lesions were detected [Figure 1b].
Follow-up preoperative imaging findings. (a) Magnetic resonance angiography image obtained on day 7 showing mild stenosis of the right M1 portion (arrow). (b) Follow-up magnetic resonance angiography image obtained on day 13 showing progression of the stenosis from M1 to the M1-M2 bifurcation (arrow). (c) Three-dimensional computed tomography angiography image obtained on day 20 showing a small 2.5-mm saccular aneurysm on the superior wall of the M2 superior trunk (arrow). (d) Three-dimensional digital subtraction angiography image obtained on day 23 showing enlargement of the saccular aneurysm (arrow).
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Head magnetic resonance angiography (MRA) showed stenosis of the right M1 portion, suggesting traumatic SAH-induced vasospasm [Figure 2a]. On day 13, we performed follow-up MRA, which showed stenosis of the M1 portion extending to the M1-M2 bifurcation [Figure 2b]. Therefore, we suspected MCA dissection and performed three-dimensional CTA on day 20, which revealed a small 2.5-mm saccular aneurysm on the superior wall of the M2 superior trunk [Figure 2c]. On digital subtraction angiography (DSA) performed on day 23, the maximal aneurysm diameter was 3.6 mm [Figure 2d].
Schematic presentation of the planned and the actual surgical strategies. (a) Preoperatively, middle cerebral artery M1-M2 trapping surgery assisted by superficial temporal artery-middle cerebral artery double-barrel bypass was planned. (b) As the laceration was limited to the superior wall of the M2 superior trunk, M2 clipping was performed assisted by superficial temporary artery-M2 superior trunk bypass to trap the lacerated point and preserve antegrade blood flow from M1 to the M2 inferior trunk. Despite the mild stenosis at the origin of the M2 inferior trunk, superficial temporal artery-M2 inferior trunk bypass was not performed.
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Hence, we decided to perform M1-M2 trapping surgery assisted by an STA-MCA double-barrel bypass [Figures 3a and 3b]. Although the origin of the M2 inferior trunk was slightly stenosed, only a proximal M2 clip was performed, and the lacerated point was trapped with titanium clips [Figures 3b and 4c].
Intraoperative findings. (a) A hard bony process is seen (arrow) attached on the surface of the dura matter along the middle meningeal artery. (b) A small laceration on the superior wall of the M2 superior trunk is observed, indicating pseudoaneurysm (arrow). (c) Trapping of the laceration point with preservation of antegrade blood flow from M1 to the M2 inferior trunk assisted by superficial temporal artery-M2 (superior trunk) bypass, despite the mild stenosis of the origin of the M2 inferior trunk. (d) Indocyanine green video angiography image showing perfect patency of the superficial temporal artery-M2 bypass, antegraded blood flow from M1 to the M2 inferior trunk and complete obliteration of the laceration on the M2 superior trunk.
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When we removed the cranial bone, we found a hard bony process attached the surface of the dura mater along the middle meningeal artery [Figure 4a]. We removed the clot at the rupture point under M1 temporary occlusion and a small laceration of approximately 10-mm was revealed along the superior wall of the M2 superior trunk [Figure 4b], which indicated that the aneurysm was a pseudoaneurysm. Although the origin of the M2 inferior trunk was slightly stenosed, only a proximal M2 clip was performed, and the lacerated point was trapped with titanium clips [Figures 3b and 4c]. Indocyanine green video angiography showed perfect patency of the STA-M2 bypass, antegrade blood flow from the M1 to the M2 inferior trunk, and LSA [Figure 4d].
Postoperative imaging findings. Postoperative digital subtraction angiography image obtained on day 56 showing excellent bypass patency (arrow) with a mild stenotic lesion of the M1-2 bifurcation and M2 inferior trunk (arrowhead).
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F5
Postoperative DSA on day 56 showed excellent bypass patency with a mild stenotic lesion at the M1-M2 bifurcation and M2 inferior trunk [Figure 5].