Posterior communicating artery aneurysm, may occur at either end of the posterior communicating artery; that is at the junction with the posterior cerebral artery, or more commonly at the junction with the carotid (typically points laterally, posteriorly, and inferiorly). May impinge on the third nerve in either case and cause third nerve palsy (ptosis, mydriasis, “down and out” deviation) that is not pupil sparing in 99% of cases. Surgical clipping may be more advantageous than endovascular coiling to treat oculomotor nerve palsies caused by p-comm aneurysms 1) 2).
Posterior communicating artery (PCOM) aneurysms is considered a internal carotid artery aneurysm.
Intracranial aneurysms arising from the posterior wall of the supraclinoid carotid artery are extremely common lesions. The aneurysm dilation typically occurs in immediate proximity to the origin of the posterior communicating artery and, less commonly, the anterior choroidal artery (AChA). Because of the increasingly widespread use of noninvasive neuroimaging methods to evaluate patients believed to harbor cerebral lesions, many of these carotid artery aneurysms are now documented in their unruptured state, prior to occurrence of subarachnoid hemorrhage. Based on these factors, the management of unruptured posterior carotid artery (PCA) wall aneurysms is an important element of any neurosurgical practice. Despite impressive recent advances in endovascular therapy, the placement of microsurgical clips to exclude aneurysms with preservation of all afferent and efferent vasculature remains the most efficacious and durable therapy. To date, an optimal outcome is only achieved when the neurosurgeon is able to combine systematic preoperative neurovascular assessment with meticulous operative technique.
They are the second most common aneurysms overall (25% of all aneurysms) representing 50% of all internal carotid artery aneurysms 3).
The next major branch of the internal carotid artery (ICA) is the posterior communicating artery, home to particularly notorious posterior communicating artery aneurysm, which seem to rupture with increased frequency for given size, when compared to other aneurysms of the ICA (ISUIA data). Next comes the anterior choroidal artery and its aneurysms, which can be mistaken for the PCOM type when the latter is hypo plastic.
see Posterior communicating artery aneurysm oculomotor nerve palsy
Posterior communicating artery aneurysm and middle cerebral artery aneurysm.
Surgery for Giant PCOM Aneurysms Video 1
Surgery for Giant PCOM Aneurysms Video 2