Clipping of ipsilateral posterior communicating and superior cerebellar artery aneurysms

The case is a 55-year-old female who presented with dizziness as the chief complaint. She has a family history of two relatives with subarachnoid hemorrhage. Digital subtraction angiography revealed the presence of a left-sided posterior communicating artery aneurysm and an ipsilateral superior cerebellar artery (SCA) aneurysm. Due to the smaller nature of the SCA, a decision was made to proceed with surgical clipping of both lesions through a pterional approach. A narrated video with illustrations depicts the intraoperative management of these lesions with postoperative angiography results. The video can be found here: http://youtu.be/HCHToSsXv-4 .

Aneurysmal subarachnoid hemorrhage with concomitant posterior communicating artery fenestration

Fenestrations of the posterior communicating artery (PCoA) are extremely rare. Associated aneurysms have only been documented three times in the literature, and none associated with a subarachnoid hemorrhage. We describe a 52-year-old female who presented with a subarachnoid hemorrhage secondary to a ruptured saccular aneurysm at the proximal limb of a fenestrated right PCoA. The patient was also found to have bilateral middle cerebral artery (MCA) aneurysms. Surgical management included surmising the etiology of the subarachnoid hemorrhage with subsequent clipping of both the right PCoA and MCA aneurysm. The potential embryological mechanisms leading to a PCoA fenestration are discussed.

Intraoperative dynamic assessment of the posterior communicating artery and its branches by indocyanine green videoangiography

Background:

True hemodynamic assessment of the posterior communicating artery (PComA) by preoperative angiography in terms of its perforators and configuration (adult vs. fetal vs. transitional) can be challenging in the surgical treatment of aneurysms involving the PComA, posterior cerebral artery, and basilar artery. Indocyanine green videoangiography (ICG-VA) is a widely accepted new technique in the surgical treatment of intracranial aneurysms to assess the patency of the parent artery, branches, and residual flow within the aneurysm after clipping.

Case Description:

Here we report two cases in which ICG-VA was utilized to assess either the direction of flow in the PComA or preservation of the PComA perforators with temporary clip application before dividing the PComA.

Conclusions:

Our experience is that ICG-VA can be used to assess the main trunk, and perforating branches of the PComA providing real-time, dynamic intraoperative information of the surgical field. Therefore we suggest that ICG-VA may increase the safety of surgical treatment of aneurysm involving PComA.

Regulation of pre-natal circle of Willis assembly by vascular smooth muscle Notch signaling

The circle of Willis (cW) is a major arterial collateral structure interconnecting hemispheric circulation within the brain, and in humans, anatomical variation of the cW is linked to stroke risk. Our prior studies on adult mice deficient in vascular smooth muscle cell (vSMC) Notch signaling revealed altered cerebroarterial maturation and patterning, including an anatomically incompetent cW similar to human variants. However, a developmental dependency on Notch signaling for cW formation in this model remained uncharacterized. Through temporospatial embryonic analyses, we now demonstrate that cW assembly is a pre-natal process highly sensitive to vSMC Notch signals, whose absence results in delayed nascent vascular plexus formation and under-development of the cW including the key anterior communicating artery (AComA) interconnecting anterior forebrain circulation. Mutant embryos additionally feature reduced vSMC coverage, non-uniform calibers and asymmetric branching at bifurcations of the major proximal cerebral arteries. At the cellular level, a notable reduction in vascular endothelial cell proliferation exists in the region of AComA assembly despite the presence of Vegfa. Furthermore, Notch signaling-deficient vSMCs in developing cerebral vessels feature reduced Pdgfrβ and Jagged1 levels and impaired proliferation. These collective findings in the embryonic brain support studies in adult animals demonstrating a reliance on intact vSMC Notch signaling for optimal neovascular responses to angiogenic stimuli. Importantly, the new data provide unique insights into the native formation of the cW and underscore a pioneering developmental role for vSMC Notch signaling in regulating temporospatial assembly of the clinically relevant cW.

Microsurgical clipping of previously coiled intracranial aneurysms

OBJECTIVE

Endovascular coiling techniques for the treatment of intracranial aneurysms have rapidly developed as an alternative option to surgical clipping. A distinct problem after endovascular coiling is the management of a residual aneurysm neck due to incomplete filling, compaction of coils or regrowth of the aneurysm. Treatment options in this situation include surgical clipping, re-coiling, stent implantation or observation.

METHODS

From June 2006 to August 2011, 15 patients underwent surgical clipping of residual or recurrent aneurysms after previous endovascular treatment. The mean age of the patients was 50.6 years (range, 27-85 years). The mean interval between coiling and clipping was 76.5 weeks (range, 0-288 weeks).

RESULTS

Thirteen patients revealed a regrowth of coiled aneurysms, and in 5 patients compaction of coils was present. Coil extrusion was observed in 9 patients intraoperatively. In case of coil obstruction at the aneurysmal neck during surgery, coils were partially or completely removed. In all cases complete occlusion of the aneurysms was surgically achieved.

CONCLUSION

Coiled aneuryms with incomplete occlusion, coil compaction or regrowth of the aneurysmal neck can be successfully treated with microsurgical clipping. Coil extrusion was more often observed intraoperatively than expected. Complete occlusion of the aneurysm can be performed safely, even if loops of coils protrude into the aneurysmal neck. In these cases intraoperative removal of the coils enables secure closure of the aneurysm with a surgical clip.

The distance between the posterior communicating arteries and their relation to the endoscopic third ventriculostomy in adults: An anatomic study

BACKGROUND

The diencephalic leaf of the Liliequist's membrane is a continuous structure that should be perforated in the endoscopic third ventriculostomy. Its lateral borders are penetrated by the third cranial nerve and the posterior communicating arteries. The most important complication of endoscopic third ventriculostomy is the vascular injury, such as the posterior communicating artery. The purpose of this study is to measure the distance between posterior communicating arteries located below the third ventricle floor and anterior of the mammillary bodies.

METHODS

In this observational prospective study 20 fresh brains from cadavers were utilized to measure the distance between the posterior communicating arteries in April 2008 at the Death Check Unit of our Institution. A digital photograph of the posterior communicating arteries was taken and the distance between the arteries was measured. The measurement was analyzed using descriptive statistics.

RESULTS

In the descriptive analysis of the 20 specimens, the posterior communicating arteries distance was 9 to 18.9 mm, a mean of 12.5 mm, median of 12.2 mm, standard deviation of 2.3 mm.

CONCLUSION

The detailed knowledge of vascular structures involved in the endoscopic third ventriculostomy as to the posterior communicating arteries distance provides a safe lateral vascular border when performing such procedure.

A review of the management of posterior communicating artery aneurysms in the modern era

Background:

Technical advancements have significantly improved surgical and endovascular treatment of cerebral aneurysms. In this paper, we review the literature with regard to treatment of one of the most common intra-cranial aneurysms encountered by neurosurgeons and interventional radiologists.

Conclusions:

Anterior clinoidectomy, temporary clipping, adenosine-induced cardiac arrest, and intraoperative angiography are useful adjuncts during surgical clipping of these aneurysms. Coil embolization is also an effective treatment alternative particularly in the elderly population. However, coiled posterior communicating artery aneurysms have a particularly high risk of recurrence and must be followed closely. Posterior communicating artery aneurysms with an elongated fundus, true posterior communicating artery aneurysms, and aneurysms associated with a fetal posterior communicating artery may have better outcome with surgical clipping in terms of completeness of occlusion and preservation of the posterior communicating artery. However, as endovascular technology improves, endovascular treatment of posterior communicating artery aneurysms may become equivalent or preferable in the near future. One in five patients with a posterior communicating artery aneurysm present with occulomotor nerve palsy with or without subarachnoid hemorrhage. Factors associated with a higher likelihood of recovery include time to treatment, partial third nerve deficit, and presence of subarachnoid hemorrhage. Both surgical and endovascular therapy offer a reasonable chance of recovery. Based on level 2 evidence, clipping appears to offer a higher chance of occulomotor nerve palsy recovery; however, coiling will remain as an option particularly in elderly patients or patients with significant comorbidity.