The extent medical literature is crowded with series on the PCAA and they are relatively rare, accounting for 2% to 9% of all intracranial aneurysms [1] - [11] . In our series, they accounted for 6.19% of all intracranial aneurysms and 9.72% of all anterior circulation aneurysms, which supports Lauri et al. rate of 6.76% [21] .

Most authors agree with Lehecka et al. who found a female predominance of 60% [1] [22] [23] , given that he has the biggest series ever published on PCAA. Our modest sample size could not support multivariate analysis of gender, which explains the lack of sex predominance observed in our series.

The mean age of patients in our study was 37 years with a range of 11 to 54 years, half of whom were less than 30 years old. Many authors report a high incidence in young adults [1] [24] . But aneurysms can be found in age groups, as Lehecka in Finland and Aboukais in France found age ranges of 4 to 59 years and 37 to 75 years respectively [1] [2] .

All 6 patients recorded a late admission, but were seen within 16 days from the time of the first symptom. Compounded factors specific to Ivory Coast including but not limited to the lack of neurosurgical centers outside Abidjan, inadequate patient transport system and healthcare system as a whole, are all limiting factors for early patient admission.

There were 5 patients with primary subarachnoid hemorrhage from a ruptured PCAA and their clinical condition on admission was WFNS I-III (83.33%). This clinical presentation is reported in more than 90% of cases of ruptured intracranial aneurysms [25] . Pertuiset [26] summarized PCAA clinical presentations into three major scenarios: subarachnoid hemorrhage with or without motor deficit and chronic intracranial hypertension syndrome with clinical features mimicking a frontal tumor.

One patient (16.67%) had an unruptured aneurysm and presented on admission with a chronic high intracranial pressure syndrome mimicking a frontal tumor. We didn’t record any patient with a WFNS grade IV-V. Aboukais reported a series of ruptured aneurysms where a third of the patients had a WFNS grade I, a third WFNS grades II-III and another third WFNS grades IV-V [2] .

The ruptured PCA aneurysms presented clearly more often with intracerebral hematoma or subarachnoid hemorrhage on the initial CT scan. Three of our patients had a Fischer grade IV and in 3 cases, the Fischer grading system was between grades I and II. Two patients presented with an intracerebral hematoma and one patient had an intraventricular hemorrhage. Two patients had a Fischer grade II. Intracerebral hematoma was associated with subarachnoid hemorrhagein 40% in our study. Lehecka et al. reported a higher incidence of intracerebral hematoma in ruptured PCAA than in other intracranial aneurysms of 17% to 73% [1] [4] [8] [11] [27] . Lehecka further explained that the narrow pericallosal and adhesions of the embedded PCA to the adjacent brain could be the reason for this high incidence [1] .

A total of 7 PCCA were recorded and they accounted for 6.19% of all intracranial aneurysms and 9.72% of all anterior circulation aneurysms.

Five PCA aneurysms occurred most frequently (71.43%) on the A3 segment of the anterior cerebral artery versus two (28.57%) on the A2 segment. Most series report rates of 69% to 82% of A3 segment aneurysms [3] [4] [5] [18] . The callosomarginal artery is believed to be where these vascular localized bulging of arterial walls occur [24] . We did not find any aneurysms on the A4 and A5 segments. In the literature, A2 and A4-A5 segment aneurysms account for 5% - 22% and 5% - 20% of all PCAA respectively [1] [3] [4] [5] [6] [8] [10] [27] [28] [29] .

Six out of seven aneurysms (85.71%) were either smaller (2 - 6 mm) or middle sized (6 - 15 mm) according to Yasargil classification system for the size of aneurysm on CT or MRI angiography [19] . There was only one (14.29%) giant PCA aneurysm. These giant PCAA are rare [16] [18] [28] . There is however, a cross-border agreement that most PCAA are smaller, as Carter et al. argued about an anatomical explanation of the size of distal arteries compared to proximal cerebral arteries [3] [4] [7] [27] [30] [31] .

Four aneurysms were saccular (57.14%), and there were only three fusiform aneurysms (42.86%). This is consistent with most studies [16] [18] [28] . Kenichiro and Mitsunori in Japan reported a series of 10 PCAA where 8 aneurysms were saccular and 2 were fusiform [24] . Many factors have been associated with the genesis of PCAA, and they are not different from those found in the genesis of other intracranial aneurysms. Lehecka and Senegor reported cases of fusiform and saccular aneurysms of the PCA caused by head trauma [28] [32] . Sypert et al. reported case of PCAA caused by Neisseria meningitidis in the United States [33] . We did not have any case of traumatic or infectious aneurysm in our series.

One patient (16.67%) had two fusiform aneurysms located on A2 segments of the 2 PCA. This is referred to as “mirror image aneurysms” [1] . In his 501 series, Lehecka found a 4% rate of mirror image aneurysms [5] [6] . Apart from the one patient who had multiple aneurysms, we didn’t find any association with other aneurysms in our series, nor did we find any PCA anatomical variation associated with any of the 7 aneurysms. The literature report a frequent association between PCAA and other intracranial aneurysms in about 25% to 55% of cases [3] [4] [5] [7] [11] [27] .

Anatomical variations should be thoroughly investigated in the planning of the surgery. Kakou et al., reported 4.34% of azygospericallosal artery in their microanatomy dissection of the azygospericallosal artery [17] . Baptista found only 0.26% of cases of a single PCA trunk and 12% of cases of a dominant PCA supplying the vast majority of the two hemispheres [15] . Cross branches of the PCA have been reported in about 26% to 64% of cases [16] [18] [28] .

It is widely admitted that microsurgical treatment of PCAA is more challenging than that of other intracranial aneurysms [1] [3] [4] [5] [7] [11] . The anatomical situation of the PCA along with morphological characteristics of the aneurysms are all contributing factors adding complexity to most microneurosurgical treatment of PCAA. Direct clipping remains nonetheless the modality of choice for total occlusion of PCAA, since it has the opportunity to provide both an immediate and a long-term viable outcome to the patient [1] [34] . The frontal interhemispheric route is the approach of choice for the microsurgical treatment of PCAA [1] [16] [18] [28] . Some authors suggest that neuronavigation should be used when accessing aneurysms on the A4 and A5 segments because of poor anatomical landmarks [1] .

All of our 7 aneurysms were treated with microsurgery using the frontal interhemispheric route. Direct clipping was performed in 4 patients with saccular aneurysms (57.14%) and 3 wrapping (42.86%) in patients with fusiform aneurysms. Lehecka clipped 98% of PCA aneurysms in his series [1] .

The median time from rupture to surgery was 59.5 days with a range of 14 to 180 days. Patients in the Lehecka series were operated within 2 days [1] . All of our patients had a late admission due to reasons clearly stated above.

Two patients developed perioperative rebleeding and in 1 case, a severe preoperative hydrocephalus was diagnosed. In 2 cases there was premature perioperative rupture of the aneurysm (33.33%). In the literature the premature rupture rate is about 50% [3] [35] [36] [37] . Surgical morbidity and mortality are estimated at 15% to 20% and 0% to 15% respectively [3] [16] [18] [35] [36] [37] .

One patient (16.67%) had postoperative persistent anosmia and, we didn’t record any fatal outcome in our series. Apart from the one patient who had a grade II moderate handicap on the Glasgow outcome scale, a 9-month follow-up revealed that the 5 remaining patients recovered fully and has since been asymptomatic.

Some authors have advocated endovascular treatment as an attractive option for PCAA, even with pretty modest series, because it is less traumatic compared to microsurgery and has the advantage to reduce postoperative infection and epilepsy rates [38] [39] . But others have been very skeptical treating PCAA using endovascular techniques because of the anatomical nature of these lesions [40] . Lehecka embolised only 12 aneurysms out of 374 in his large aneurysm series making just 3.2%. Of all the 12, 7 were incompletely occluded and 4 had to be re-embolised and 3 clipped. Ivory Coast is currently and technically not yet ready for endovascular procedures.