Bilateral extradural PICA origins at the point at which the VA ascends between the transverse foramina of C-2 and C-1, simultaneously exist right double origin PICA: a rare case report and literature review.

BACKGROUND: The location of the origin of the PICA is highly variable. An extracranial origin PICA from the vertebral artery(VA) is not rare. But, the PICA originated extradurally at the point at which the VA ascends between the transverse foramina of C-2 and C-1 is one very rare anatomic variant. Double origin PICA (DOPICA) is another one very rare anatomic variant observed in 1% to 4% of patients in which 2 PICA branches converge distally.

CASE DESCRIPTION: We present an rare cadaveric anatomy case which both the PICAs originated extradurally between the vertebrae C1 and C2, simultaneously exist right double origin PICA . For this case,the right PICA was a double-origin PICA, Including one extradural orgin which the VA ascends between the transverse foramina of C-2 and C-1,another one was intradural and Intracranial one.

CONCLUSIONS: To our knowledge, this is the first report of cadaveric anatomy case of bilateral PICA originated extradurally between the vertebrae C1 and C2,and simultaneously exist right double origin PICA (DOPICA).This kind of case is very rare,but the understanding of this anatomical variation is very important.To avoid complications during surgery at the craniovertebral junction, these potential variations should be correctly identified preoperatively.