PMC6884950_01
Preoperative magnetic resonance imaging showing giant thrombosed vertebral artery aneurysm at left V4 portion compressing the medulla oblongata contralaterally.
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F1
The GTVA also demonstrated a heterogenic signal intensity suggesting different stages of thrombus formation inside the aneurysm [Figure 1].
Preoperative digital subtraction angiography showing serpentine aneurysm of the left vertebral artery with normal appearance distal V4 segment which was pushed up distally and thus bending toward the internal auditory canal. The posterior inferior cerebellar artery was possibly incorporated in the lesioned part and retrogradely opacified through the ipsilateral superior cerebellar artery and its pial anastomosis.
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F2
As such, the distal portion of the corresponding PICA was retrogradely opacified through the ipsilateral superior cerebellar artery (SCA) and its pial anastomosis [Figure 2].
The schema demonstrating the actual surgical design of the final situation: trapping of the aneurysm and intraluminal thrombectomy, followed by V3-radial artery graft-V4 bypass reconstruction, in conjunction with possible occipital artery- posterior inferior cerebellar artery bypass.
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L shaped skin incision was designed and a lateral suboccipital craniotomy was made followed by the drilling of ipsilateral magnum, condylar fossa as well as sigmoid sinus exposure.
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An L-shape skin incision was performed, and the skin flap was reflected medially [Figure 4].
The intraoperative images. (a) The occipital artery (OA) was harvested from the exit of the digastric groove to the entry to the skin. (b) V3 portion of the left vertebral artery was exposed in the suboccipital triangle. (c) Left suboccipital craniotomy and far-lateral drilling were performed. (d) The giant thrombosed vertebral artery aneurysm (GTVA) compressing the medulla oblongata as well as the spinal root of the 11th nerve medially was exposed. (e) The GTVA was trapped between V3 portion and just distal to the dilated segment. (f) Intraluminal laminated thrombus was removed. (g and h) V3-radial artery graft-V4 bypass was performed through the space lateral to the 11th nerve. (i) Finally, OA-posterior inferior cerebellar artery anastomosis was added.
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The suboccipital muscles were dissected and reflected layer-by- layer, and the OA was simultaneously harvested from the exit of the digastric groove to the entry to the skin, in the layer between the splenius capitis and semispinalis capitis muscles [Figure 5a]. The superior oblique muscle was reflected in the attachment on the C1 lateral mass, and the horizontal segment (V3) of the VA was exposed in the suboccipital triangle [Figure 5b]. This provided a maximum surgical field through the triangle made by the medulla, the spinal root of the 11th nerve, and the lower cranial nerves (LCNs) complex [Figure 5c]. The GTVA was so large that the medulla oblongata and the spinal root of the 11th nerve were deviated medially [Figure 5d]. Therefore, we trapped the aneurysm between the V3 portion and just distal to the dilated segment [Figure 5e], and then incised the aneurysmal wall and removed the intraluminal laminated thrombus through the space lateral to the 11th nerve [Figure 5f]. The stump of the V4 was made fish mouth-like, and end-to-end anastomosis with RAG was performed through the triangular corridor, lateral to the medially-deviated 11th nerve/medulla, inferior to the LCNs, and medial to the sigmoid sinus [Figure 5g]. Another end of the RAG was anastomosed to the V3 portion in an end-to-side method, and the V3-RAG-V4 bypass was completed [Figure 5h]. Therefore, we added an OA-PICA anastomosis in an end-to- side method [Figure 5i].
Postoperative magnetic resonance imaging showing improvement of the brain stem compression.
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Postoperative MRI and DSA demonstrated the disappearance of the aneurysm, improvement of brainstem compression, and good patency of each bypass [Figures 6 and 7].
Postoperative digital subtraction angiography demonstrating good patency of each bypass.
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Postoperative MRI and DSA demonstrated the disappearance of the aneurysm, improvement of brainstem compression, and good patency of each bypass [Figures 6 and 7].