PMC8088539_01
Preoperative images of the case. (a) Coronal gadolinium-enhanced T1-weighted magnetic resonance imaging shows that the tumor envelops the epipharyngeal region to the sphenoid sinus and the skull base. (b) Lateral view of fusion image between computed tomography angiography and tumor (purple color) reconstructions. Tumor engulfs the right side internal and external carotid arteries. (c) Computed tomography angiography reveals that the tumor envelopes the sphenoid sinus and the right side carotid canal. The bony structure of the carotid canal is dissolved by the tumor.
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F1
Computed tomography (CT), CT angiography (CTA), and magnetic resonance imaging (MRI) revealed a heterogeneous mass occupying the epipharyngeal region [Figure 1].
Intraoperative findings. (a) Right skin incision design. The frontotemporal skin incision is designed from just above the superficial temporal artery parietal branch to the hair's midline. To join this skin incision, an additional curved one along the lateral process of the C2 vertebra is added. (b) The sternocleidomastoid and occipital muscles are exposed. (c) The occipital muscle is elevated as it belongs to the skin flap by detaching it from the superior nuchal line. (d and e) The suboccipital triangle is exposed. (f) The V3 portion of the vertebral artery is exposed.
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F2
The skin incision was designed, as shown in [Figure 2a]. To do this, the sternocleidomastoid (SCM) muscle and occipital muscle were exposed first [Figure 2b], and insertion of those muscles had to be exposed. Then, the occipital muscle was elevated as belonging to the skin flap by detaching it from the superior nuchal line [Figure 2c]. After exposing the suboccipital muscle triangle [Figures 2d and e], the V3 segment of the VA was exposed [Figure 2f].
Intraoperative findings of the V3-radial artery graft -M2 bypass. (a) Superior trunk of the M2 is considered as a recipient artery once Sylvian fissure dissection is complete. (b) At first, superficial temporal artery to the M3 portion of the middle cerebral artery (MCA) bypass is performed. (c) The M2 portion of the MCA to RAG anastomosis is performed. (d) The mastoid and the temporal bones are drilled just below the graft route not to compress the graft and make the graft route shorter. (e) V3 to RAG anastomosis is performed. (f) Indocyanine green video angiography demonstrates good filling of the V3-RAG-M2 bypass. (g) Schematic image of the pressure monitoring.
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F3
By distal Sylvian fissure dissection, the M1 to M3 portion of the MCA was fully exposed [Figure 3a]. The STA-MCA bypass was performed before M2-RAG anastomosis [Figure 3b]. Once the STA-MCA bypass was performed, the M2-RAG anastomosis was performed in an end-to-side manner [Figure 3c]. The graft route was determined by adjusting the contralateral end of the RAG to the V3 segment of the VA, and the mastoid and temporal bones were drilled just below the graft route to avoid compression of the graft and shorten the graft route [Figure 3d]. An end-to-side V3-RAG anastomosis was then performed [Figure 3e]. Using Doppler, indocyanine green video angiography, and pressure monitoring, graft patency, and flow were identified [Figures 3f and g].
Postoperative courses. (a and b) The reconstruction of the computed tomography angiography in lateral view reveals good filling of the V3-radial artery graft (RAG)-M2 and superficial temporal artery -middle cerebral artery bypass. The internal carotid artery is not occluded at this time. (c) The cavernous portion of the internal carotid artery (ICA) is occluded by coil, lateral view of angiography image. (d) The cervical ICA is occluded, oblique view of angiography image. (e and f) Anterior to the posterior and lateral view of the digital subtraction angiography after ICA occlusion shows good filling of the V3-RAG-M2 bypass.
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F4
The ICA was occluded using endovascular coiling the day after systemic heparinization [Figure 4].