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How I do it? Posterior inferior cerebellar artery-intracranial vertebral artery reimplantation bypass and trapping of dissecting aneurysm involving the proximal posterior inferior cerebellar artery



Proximal posterior inferior cerebellar artery (PICA) aneurysms are surgically challenging due to the high variability in the anatomy of the PICA origin, their deep-seated nature, and their entanglement with the lower cranial nerves. Direct or reconstructive clipping may not be achievable if the aneurysm is large, or dissecting, or exhibits atherosclerosis or calcification.


We present a case of a proximal PICA lateral medullary segment (P2) aneurysm that was successfully cured by trapping the aneurysm and reconstructing the PICA using the PICA-intracranial vertebral artery (PICA-V4) via end-to-side reimplantation bypass with the far lateral approach.


This case demonstrates the feasibility and safety of PICA-V4 reimplantation bypass, especially if the origin of the PICA is highly seated and the intracranial VA, or V4 segment, is long enough and well-exposed supra or under hypoglossal nerves.

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Correspondence to Wei Zhu.

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A video of a surgical case is presented. The patient approved this publication.

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The authors declare no competing interests.

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Key points

1. Preoperative cerebral angiography should be carefully analyzed for PICA aneurysm angioarchitecture evaluation and surgical planning

2. IC-IC bypass was the first choice because remote donor artery or graft harvesting is unnecessary, and IC-IC bypass provides better dural closure.

3. The far lateral approach was appropriate for proximal PICA aneurysms.

4. PICA-V4 reimplantation was appropriate for proximal PICA aneurysm with PICA originating high from the VA superior and inferior to the hypoglossal nerves.

5. Intraoperative electrophysiological monitoring is essential for brainstem ischemia warning.

6. Dentate ligament transection is essential to decrease the interference of the lower cranial nerves in aneurysm access.

7. Meticulous and skilled deep bypass techniques are critical for safe bypass surgery.

8. During the bypass, we used Prolene 10-0 sutures. We first placed an anchor suture at the distal corner of the anastomotic stoma. Then, an opposite anchor suture was placed. Interrupted sutures were used.

9. Considering the thickness of the VA intima, interrupted sutures should be used to sew up both the intima and adventitia to avoid artery dissection formation.

10. A Doppler probe, intraoperative indocyanine green, and even angiography should be applied to assess the aneurysm obliteration and bypass patency.

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Zixiao Yang and Jianping Song are the first two authors contributed equally to this work.

This article is part of the Topical Collection on Vascular Neurosurgery - Aneurysm

Supplementary Information

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This video illustrates a PICA P2segmentgiant dissecting aneurysm trapped with PICA-intracranial vertebral artery (PICA-V4) end-to-side reimplantation using a far lateral approach (MP4 104825 KB)

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Yang, Z., Song, J., Li, P. et al. How I do it? Posterior inferior cerebellar artery-intracranial vertebral artery reimplantation bypass and trapping of dissecting aneurysm involving the proximal posterior inferior cerebellar artery. Acta Neurochir 163, 2973–2976 (2021).

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  • Intracranial aneurysm
  • Posterior inferior cerebellar artery
  • Vertebral artery
  • Reimplantation bypass