Surgical removal using V3-radial artery graft-V4 bypass and occipital artery-posterior inferior cerebellar artery bypass for a giant thrombosed aneurysm of vertebral artery compressing brain stem: Case report

Abstract

Background: Giant thrombosed vertebral artery aneurysms (GTVAs) are difficult disease to treat. Here, we are reporting a case of GTVA successfully treated with excluding the pathological segment and restoring the anterograde blood flow of the parent artery, highlighting the reliable surgical procedure.

Case description: A 55-year-old man with a left GTVA complained of right hemiparesis (manual muscle testing 4/5) represented by hand clumsiness and gait disturbance, in addition to severe left-sided dysesthesia, was referred to our hospital. The posterior inferior cerebellar artery (PICA) was incorporated into the GTVA segment, and the contralateral vertebral artery showed atherosclerotic change. Thus, we decided to treat the aneurysm with aneurysm trapping and thrombectomy, in conjunction with V3-radial artery graft (RAG)-V4 bypass and occipital artery (OA)-PICA bypass through a suboccipital transcondylar approach. The distal end of the dilated segment was meandering and deflecting outwardly to the vicinity of the internal auditory canal and was stretched in an axial direction. Thus, the V4 stump can be transposed to the triangle space made by the medulla, lower cranial nerves, and sigmoid sinus, and we could perform a safe and reliable anastomosis through the corridor. After the surgery, the compression of the brain stem was released, and right hemiparesis was improved completely after rehabilitation. The patient was discharged with a modified Rankin Scale score of 1.

Conclusion: Trapping of the aneurysm and thrombectomy are the most radical treatment for GTVA, and if possible, reconstruction of anterograde blood flow with V3-RAG-V4 bypass and OA-PICA bypass is desirable.

Keywords: Giant thrombosed aneurysm; Occipital artery-posterior inferior cerebellar artery bypass; Reconstruction; V3-radial artery graft-V4 bypass.

Figure 1:

Preoperative magnetic resonance imaging showing giant thrombosed vertebral artery aneurysm at left V4 portion compressing the medulla oblongata contralaterally.

Figure 2:

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.

Figure 3:

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.

Figure 4:

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.

Figure 5:

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 11^th 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 11^th nerve. (i) Finally, OA-posterior inferior cerebellar artery anastomosis was added.

Figure 6:

Postoperative magnetic resonance imaging showing improvement of the brain stem compression.

Figure 7:

Postoperative digital subtraction angiography demonstrating good patency of each bypass.