PcomA Aneurysms Research Articles

Intradural “limited drill” technique of anterior clinoidectomy and optic canal unroofing for microneurosurgical management of ophthalmic segment and PCOM aneurysms—review of surgical results

To evaluate the safety and efficacy of intradural "limited drill" technique (ILDT) of anterior clinoidectomy (AC) and optic canal unroofing (OCU) for microneurosurgical management of ophthalmic segment and posterior communicating artery (PCOM) aneurysms. All the patients with ophthalmic segment and PCOM aneurysms who underwent AC and OCU by ILDT for microneurosurgical management of ophthalmic segment and PCOM aneurysms during 4-year period (2013-2016) at our Institute were included in this study. In ILDT of AC and OCU, the use of power drill is restricted to AC only and OCU is done exclusively with 1-mm Kerrison punch. AC and OCU by ILDT were done in 24 patients with 29 ophthalmic segment and 7 PCOM aneurysms. AC and OCU by ILDT helped in mobilization of optic nerve/internal carotid artery (ICA) and provided excellent exposure for all these aneurysms. There was no injury to ICA or optic nerve during drilling. AC and OCU facilitated clip ligation of 34 of these aneurysms. Remaining 2 aneurysms were considered not suitable for clipping. Check angiogram done for 33 aneurysms revealed complete obliteration of 26 aneurysms, very small residual neck in 5 aneurysms, and small residual aneurysm in 2 aneurysms. Deterioration in vision was noted in 1 patient (4.1%). In 6 patients with preoperative visual deficits, significant improvement in vision was noted in 4 patients (4/6-66.6%) after surgery. Good outcome (MRS < 2) was noted in 91.6% (22/24) of these patients. ILDT is a safe and effective technique of AC and OCU which provide good exposure for ophthalmic segment and PCOM aneurysms.

GIANT CEREBRAL ANEURYSMS AND THEIR FLOW-DIVERT STENT TREATMENT

The purpose of the article is to show the very rare bone-wound brain aneurysm found in our practice in Azerbaijan. Material and methods. In our clinical practice, between 2000 and 2018, surgical treatment of 118 cerebral aneurysms was performed. Only 3 of them have giants (25mm&gt;) aneurysm. Clinical observation and screening images were kept under control. Results. 2 of 3 patients applied to our clinic with hemorrhage. One patient was hospitalized with emergency hemicraniotamia, but there was not possible to save his life. His aneurysm was not threated. Other 2 patient's aneurysms were operated: First case was unruptured giant Pcom aneurysm. Successfuly ocluded with 2 flow divert stent implantation. Second patient received 2-stage endovascular treatment. Coiling and later flow-divert stent implantation. Conclusion. The evidence of giant aneurysms is 1%. Nevertheless, these aneurysms tend to bleed extremely high. On the other hand, rupture the giant’s aneurysms scarring in death. Because of microsurgical cliping is quite risky, these patients are usually going to endovascular threatment. Recently, the use of flow-diverts stents has decreased the rysk of intraoperative complications and increase occlusion of aneurysms. These stents, which are currently being applied in our country, showed a low risk and high percentage of occlusion of aneurysms.

Recovery of oculomotor nerve palsy after endovascular and surgical treatment of posterior communicating artery aneurysms: A single institutional experience

Introduction:Surgical oculomotor nerve palsy(ONP), defined by ptosis, ophthalmoplegia, diplopia and pupillary dilatation, is associated with intracranial aneurysms, especially posterior communicating artery (PcomA) aneurysms. Treatment of PcomA aneurysms include endovascular coiling and surgical clipping. This study retrospectively compared the recovery of ONP in patients who underwent endovascular coiling or surgical clipping.Methods:A retrospective review of patients with PcomA aneurysms who presented with ONP between 1998 and 2012 in the National Neuroscience Institute, Singapore, was performed. Inclusion criteria included adult patients of age above 21 who have radiologically confirmed PcomA aneurysms with presentation of ipsilateral ONP. The aneurysms may be unruptured or ruptured with WFNS grade 2 subarachnoid hemorrhage (SAH) or better. Only patients with completely surgically or endovascularly obliterated PcomA aneurysms with regular follow-up are included.Results:A total of 22 patients were recruited. They were treated by either endovascular coiling or surgical clipping. The two groups of patients were demographically comparable, with 11 patients in each arm. 13 (59%) patients had unruptured aneurysms and 9 (41%) had WFNS grade 2 or better SAH. 13 (59%) patients presented with complete ONP and 9 (41%) had partial ONP. 64% of patients who underwent surgical clipping had resolution of ONP completely, compared to 18% of endovascularly coiling (P = 0.03) at 1-month follow-up.Conclusion:Compared to endovascular coiling, surgically clipped PcomA aneurysms are associated with a faster rate of full recovery of ONP.

Development of a statistical model for discrimination of rupture status in posterior communicating artery aneurysms.

Intracranial aneurysms at the posterior communicating artery (PCOM) are known to have high rupture rates compared to other locations. We developed and internally validated a statistical model discriminating between ruptured and unruptured PCOM aneurysms based on hemodynamic and geometric parameters, angio-architectures, and patient age with the objective of its future use for aneurysm risk assessment. A total of 289 PCOM aneurysms in 272 patients modeled with image-based computational fluid dynamics (CFD) were used to construct statistical models using logistic group lasso regression. These models were evaluated with respect to discrimination power and goodness of fit using tenfold nested cross-validation and a split-sample approach to mimic external validation. The final model retained maximum and minimum wall shear stress (WSS), mean parent artery WSS, maximum and minimum oscillatory shear index, shear concentration index, and aneurysm peak flow velocity, along with aneurysm height and width, bulge location, non-sphericity index, mean Gaussian curvature, angio-architecture type, and patient age. The corresponding area under the curve (AUC) was 0.8359. When omitting data from each of the three largest contributing hospitals in turn, and applying the corresponding model on the left-out data, the AUCs were 0.7507, 0.7081, and 0.5842, respectively. Statistical models based on a combination of patient age, angio-architecture, hemodynamics, and geometric characteristics can discriminate between ruptured and unruptured PCOM aneurysms with an AUC of 84%. It is important to include data from different hospitals to create models of aneurysm rupture that are valid across hospital populations.

Risk Factors and Morphological Differences of Ruptured Saccular Aneurysm in Different Sites of Anterior Circulation in Patients Presenting with Subarachnoid Haemorrhage

Background: All sites of intracranial aneurysms have always been considered together in most of the studies of risk factors of aneurysm rupture. Therefore, it is not known whether some risk factors predispose to aneurysm rupture at a particular location. Morphologies also vary in accordance to different sites of the aneurysm.Objective: The purpose of the present study was to observe the differences in the risk factors, the size, aspect ratio and size ratio among the anterior circulation aneurysms.Methodology: This hospital based cross-sectional study carried out in the Department of Neurology at Dhaka Medical College Hospital (DMCH), Dhaka during July 2013 to June 2015 for a period of two (02) years. Patients with subarachnoid haemorrhage caused by ruptured anterior circulation saccular aneurysms admitted in the Departments of Neurology, Internal Medicine and Neurosurgery Departments at Dhaka Medical College Hospital (DMCH), Dhaka and the Department of Neurointervention at National Institute of Neurosciences and Hospital, Dhaka were enrolled in this study. Patients’ ≥18 years of age with subarachnoid haemorrhage caused by anterior circulation aneurysm which was confirmed by computed tomogram (CT-scan) and/or CSF study and digital subtraction angiography were included in this study. The risk factors were identified by interviewing the patients and the morphology were measured from the digital subtraction angiogram.Results: A total number of 85 patients with ruptured saccular anterior circulation aneurysm were enrolled in this study. In this study anterior communicating artery aneurysm (ACom) was the most frequent site of aneurysm (42%). The mean age of the patients with ACom aneurysm (51.72 ± 9.26 years) was significantly higher than posterior communicating artery (47.5 ± 8.2 years) aneurysm and middle cerebral artery (MCA) (43.41 ± 8.0 years) aneurysm. Above the age of 50 ACom aneurysm was the most frequent aneurysm (OR 5.5, p&lt;0.05). Among the female Posterior communicating artery (PCom) aneurysm (46.7%) was the most frequent aneurysm and among the male ACom aneurysm (37.5%) was the most frequent aneurysm. Family history was exclusive in MCA aneurysm (3.5%). The mean size of MCA (7.79 ± 0.71 cm) was higher than ACom (6.12 ± 2.7cm) aneurysm and PCom (6.5 ± 2.4 cm) aneurysm and proportion of aneurysm &gt;10 mm was also higher among the middle cerebral artery (35.6%) aneurysms. The size ratio was significantly higher in ACom (3.08±1.23) and MCA (3.04±0.97) aneurysm. ACom (76.4%) and MCA (83.3%) had also more frequent high risk size ratio.Conclusion: In conclusion anterior circulation aneurysms differ in respects of risk factors and morphology.Journal of National Institute of Neurosciences Bangladesh, 2017;3(1): 21-28

Recovery of oculomotor nerve palsy after endovascular treatment of ruptured posterior communicating artery aneurysm.

Oculomotor nerve palsy (ONP) may result from Posterior communicating artery (Pcom) aneurysms. Endovascular treatment of ruptured Pcom aneurysms generally is a safe procedure, but the effect of this therapy on ONP is incompletely elucidated. This retrospective study evaluates outcomes of ONP after endovascular treatment for ruptured Pcom aneurysm and with the intention to clarify predictors of recovery. From May 2010 to October 2015, 210 patients with Pcom aneurysms underwent endovascular treatment at our institution. Among them, 34 patients with ruptured aneurysms and either complete or incomplete ONP were identified. The outcomes and predictors of ONP recovery were analyzed. At the last available clinical follow-up, ONP resolution was complete in 21 (61.8%) patients and incomplete in 8 (23.5%) patients. The mean resolution time after embolization was 24.5days. Five patients showed no signs of ONP recovery. In no case was an initial incomplete ONP observed to worsen. There was a statistically insignificant trend toward complete recovery among patients with initial incomplete ONP (OR=4.17; 95% CI, 0.75-23.18; P=0.103). Endovascular treatment appears to be an effective treatment modality for ruptured Pcom aneurysm and related ONP. The initial incomplete ONP might encourage complete ONP recovery after endovascular treatment.

CTA analysis and assessment of morphological factors related to rupture in 413 posterior communicating artery aneurysms.

Posterior communicating artery (PcomA) aneurysms are frequently encountered, but there are few publications on their morphology. A growing number of aneurysms are incidental findings, which makes evaluation of rupture risk important. Our goal was to identify morphological features and anatomical variants associated with PComA aneurysms and to assess parameters related to rupture. We studied CT angiographies of 391 consecutive patients treated between 2000 and 2014 at a single institution. We determined clinically important morphological parameters and performed univariate and multivariate analysis. There were a total of 413 PComA aneurysms: 258 (62%) were ruptured and 155 (38%) unruptured. Ruptured PComA aneurysms had the potential to cause severe bleeding with IVH and/or temporal ICH (n=170, 66%of ruptured). The main types of PComA origin were classified as follows: (1) separate (32%), (2) side by side (21%) and (3) a joint neck with the aneurysm (6%). After the multivariate logistic regression, the morphological parameters related to PComA aneurysm rupture were an irregular aneurysm dome, neck diameter, and aspect ratio>1.5. The most marked morphological features of the PComA aneurysms were: saccular nature (99%), infero-posterior dome orientation (42%), infrequency of large or giant aneurysms (4%), narrow neck compared to the aneurysm size, PComA originating directly from the aneurysm neck or the dome (28%), and fetal or dominant PComA on the side of the aneurysm (35%). There were location-related parameters that were more strongly associated with PComA aneurysm rupture than aneurysm size: an irregular aneurysm dome, larger diameter of the aneurysm neck and aspect ratio>1.5.

Pipeline embolization of posterior communicating artery aneurysms associated with a fetal origin posterior cerebral artery

Background and purposeFlow diversion may have advantages in the treatment of posterior communicating artery (PComA) aneurysms associated with a fetal origin posterior cerebral artery (PCA), which can be challenging to treat with conventional techniques. However, a PComA incorporated into the aneurysm may prevent or delay aneurysm occlusion. Also, coverage of a fetal origin PCA risks infarction of a large vascular territory. The purpose of this study was to examine the safety and effectiveness of using the Pipeline Embolization Device (PED) to treat PComA aneurysms associated with a fetal origin PCA. Patients and methodsRetrospective review of PComA aneurysms associated with a fetal origin PCA treated with the PED at two neurovascular centers was performed. Periprocedural complications and clinical and angiographic outcomes were reviewed. ResultsSeven female patients underwent a total of seven PED procedures to treat seven PcomA aneurysms associated with a fetal origin PCA. The symptomatic complication rate was 14% (1/7) per patient and 13% (1/8) per procedure. Angiographic follow up was obtained for 6 of 7 aneurysms. Follow-up DSA at 5–7 months after treatment demonstrated complete occlusion of 17% (1/6) of aneurysms. One aneurysm was retreated with a second PED and occlusion was demonstrated 36 months after the second treatment, yielding an overall complete occlusion rate of 33% (2/6). ConclusionsPED treatment was largely ineffective at treating PComA aneurysms associated with a fetal origin PCA, and should only be considered when conventional treatment options, including microsurgical clipping, are not feasible.

Small versus Large Ruptured Intracranial Aneurysm: Concerns with the Site of Aneurysm

Background: Although size is one of the strongest predictors, small aneurysms often rupture. We compared the characteristics of small and large ruptured intracranial aneurysms (RIAs) according to their location to find the factors associated with small RIAs in each location. Methods: Patients with subarachnoid hemorrhage due to saccular RIAs were consecutively enrolled. The sizes were dichotomized as small (<5 mm) or large, and the location was classified as paraclinoid-distal internal carotid artery, sidewalls of anterior or middle cerebral artery (MCA; sidewall), MCA-bifurcation, anterior or posterior communicating artery (Acom or Pcom, respectively), and posterior circulation RIAs. Independent factors associated with small RIAs compared to large RIAs were investigated in each location. Results: Small RIAs were observed in 384 of 791 patients (48.5%), and were most commonly located at Acom (17.1%) followed by Pcom (9.0%) and sidewalls (7.2%). Female sex (OR 3.038; 95% CI 2.099-4.395), young age (OR 0.971; 95% CI 0.958-0.985), hypertension (OR 1.412; 95% CI 1.033-1.930) and multiple aneurysms (OR 1.942; 95% CI 1.335-2.824) were associated with small RIAs. By location, sidewall aneurysms (OR 2.183; 95% CI 1.049-4.542) were associated with small RIAs, whereas MCA-bifurcation (OR 0.318; 95% CI 0.168-0.599) and Pcom aneurysms (OR 0.511; 95% CI 0.277-0.944) were associated with large RIAs. The presence of multiple aneurysms (OR 4.69; 95% CI 1.45-21.19) was associated with small RIAs at sidewalls, and young age, female sex, hypertension and the presence of bilateral A1 (OR 1.85; 95% CI 1.09-3.13) were associated with small RIAs at Acom. Acom RIAs with bilateral A1 was smaller than those with unilateral A1 (4.7 ± 2.1 vs. 5.8 ± 2.6 mm; p < 0.001). Conclusions: Intracranial aneurysms which rupture below 5 mm are not uncommon, and the factors associated with small-sized RIAs differ according to location. Sidewall aneurysms, with multiple aneurysms and Acom aneurysms with bilateral A1 may rupture even at small size.

To wait for a spontaneous recovery of the third cranial nerve palsy occurring after the coiling of a PcomA aneurysm or to implement surgical treatment? A case report

To wait for a spontaneous recovery of the third cranial nerve palsy occurring after the coiling of a PcomA aneurysm or to implement surgical treatment? A case report

Aneurysmal bleed in traumatic SAH: are we missing something serious?

Introduction and Objective: Spontaneous Subarachnoid hemorrhage (SAH) is usually due to aneurysm rupture (85%) however SAH is far common in traumatic brain injury (TBI) (60%). We did an audit to see proportion of our patients with TBI with SAH and their outcomeMaterials and Methods: We did a retrospective study of patients admitted with Department of neurological surgery since April 2012 till Jan 2016. We included all patients with traumatic SAH and subjected patients with significant cisternal bleed or history of dizziness or headache prior to fall or injury to brain CT angiography. Patient who could not be properly evaluated despite suspicion were excluded. Endpoints studied were outcome, hospital stay and morbidity.Results: 112 patients were studied of which 63 were males and mean age was 48.2 years. Total of 5 cases (4.5%) had intracranial aneurysm. Of these, 3 were PCOM aneurysm and 2 from ACOM. These were successfully clipped and no significant difference in hospital stay or morbidity was seen. Of the other followed up patients, none had recurrent bleed. We discuss our approach and limitations of this study.Conclusion: 5% patients with traumatic SAH had aneurysm. A high index of suspicion and early clipping of aneurysm in such cases is associated with good outcome.

Resolution of third nerve palsy despite persistent aneurysmal mass effect after flow diversion embolization of posterior communicating artery aneurysms

Posterior communicating artery (PCOM) aneurysms may cause third nerve palsies. The optimal treatment with clipping versus coiling remains controversial. Here we report on two cases of resolution of third nerve palsy after flow diversion embolization of large and giant PCOM aneurysms without adjuvant coil placement. The resolution of third nerve palsy was not preceded by significant shrinkage of the aneurysmal sac on MRI. However, one patient showed resolution of T2-weighted signal abnormalities in the midbrain and mesial temporal lobe despite a similar size of the aneurysm. Therefore, flow diversion embolization of a PCOM aneurysm may resolve oculomotor nerve palsies through decreasing arterial pulsations against the nerve or midbrain.

Morphological Risk Factors for Rupture of Small (

The management of small, unruptured intracranial aneurysms is still controversial. Given the distinctive natural history of aneurysm at different locations, location-specific analysis might be a reasonable approach. This study aimed to investigate morphological discriminators for rupture status by focusing on only posterior communicating artery (PcomA) aneurysms smaller than 7 mm. In 108 small PcomA aneurysms (68 ruptured, 40 unruptured), clinical and morphological characteristics were compared between the ruptured and unruptured groups. Multivariate logistic regression analysis was performed to determine the independent predictors for the rupture status of small PcomA aneurysms. None of the clinical characteristics were significantly different between the ruptured and unruptured groups (P > 0.05). The ruptured group revealed a significantly larger size (P = 0.009), aspect ratio (P = 0.009), size ratio (P = 0.002), dome-to-neck ratio (P = 0.002), inflow angle (P < 0.001), and proportion of bleb formation (P = 0.039). Bottleneck factor (P = 0.154), diameter of PcomA (P = 0.302), and fetal-type PcomA (P = 0.832) showed no significance. With multivariate analyses, size ratio (P = 0.012) and inflow angle (P = 0.001) were shown to be independently associated with the rupture status of small PcomA aneurysms. Morphological characteristics were closely related with the rupture status of small PcomA aneurysms. Size ratio and inflow angle were independent risk factors for rupture and might be useful in clinical risk stratification of small PcomA aneurysms.

Morphological Predictors of Posterior Communicating Artery Aneurysms Rupture

Objective The conflicting findings of previous morphological studies on intracranial aneurysm rupture may be caused by the different locations of aneurysms. We aimed to determine the independent risk factors of aneurysm rupture by focusing on only posterior communicating artery (PcomA) aneurysms. Methods In 89 PcomA aneurysms (58 ruptured, 31 unruptured), clinical and morphological characteristics were compared between the ruptured and unruptured groups. Multivariate logistic regression analysis was performed to determine the independent predictors for the rupture status of PcomA aneurysms. Results In univariate analyses, the aneurysm dome size, aspect ratio, size ratio, dome-to-neck ratio, and inflow angle were significant parameters. With multivariate analyses, only the aneurysm dome size and inflow angle were significantly associated with the rupture status of PcomA aneurysms. Conclusions Morphology was related with rupture of PcomA aneurysms. The aneurysm dome size and inflow angle were found to be the independent parameters characterizing the rupture status of PcomA aneurysms.

Endovascular treatment of posterior communicating artery aneurysms in the presence of the fetal variant of posterior cerebral artery.

Posterior communicating artery (PcomA) aneurysms in the presence of the fetal variant of posterior cerebral artery (PCA) often pose technical challenges for endovascular treatment because of a greater potential for ischemic injury with the fetal PCA compromise. The purpose of this study was to assess the feasibility and results of endovascular treatment for these lesions. We retrospectively reviewed our experience and results of endovascular treatments for a series of nine consecutive patients with PcomA aneurysms occurring at the origin of fetal PCAs at the Department of Neurosurgery of Southwest Hospital, Chongqing, China, between June 2011 and June 2014. Depending on the angiographic findings, location and shape of the aneurysms, various therapeutic strategies were used including coiling by single or double microcatheter, balloon remodeling technique, and single or Y-stenting technique. Overall, fetal PCA was preserved patent in all cases, and complete or near complete occlusion was achieved in 8/9 cases. There was no procedure-related morbidity or mortality. With the exception of one patient who died of pneumonia 6 weeks after treatment, no clinical evidence of neurologic deterioration and hemorrhagic complication was seen during the follow-up period in the remaining 8 patients. Our experience suggests that endovascular treatment is relatively safe and technically feasible in most patients with PcomA aneurysms in the presence of fetal PCA using multiple strategies.

Novel Aneurysm Grown from a PcomA Infundibulum after Embolization of a Contralateral Posterior Communicating Aneurysm in an Isolated Polycystic Hepatic Patient: A Case Report

We present a case of a posterior communicating (Pcom) artery infundibulum that progressed to an aneurysm in a patient with Polycystic liver disease without kidney cyst after embolization of the controlateral Pcom aneurysm. The infundibulum had been documented on angiography 4 years earlier, while a ruptured controlateral Pcom aneurysm was embolised. The patient presented to the outpatient clinic with right postorbital headache and cranial Ⅲ nerve palsy. Head CT scan found no gross subarachnoid hemorrhage. Though MR angiography note a 7-mm pcom aneurysm at the previous site of Pcom infundibulum. The patient underwent coiling for the novel aneurysm with a good result. This case illustrates a small but growing number of cases which developed from infundibula into aneurysms. It suggests that polycystic disease may pose an additional risk for infundibulum while what has traditionally been considered as a benign lesion.

Morphological and hemodynamic analysis of posterior communicating artery aneurysms prone to rupture: a matched case–control study

ObjectivesWe evaluated the correlation between posterior communicating artery (PcomA) aneurysm rupture and morphological and hemodynamic parameters to assess related rupture risk indices.MethodsSix patients with PcomA aneurysms that ultimately ruptured (cases)...

Recovery from oculomotor nerve palsy due to posterior communicating artery aneurysms: results after clipping versus coiling in a single-center series

Oculomotor nerve palsy (ONP) is a common clinical manifestation of ruptured or unruptured posterior communicating artery (PcomA) aneurysms. Although microsurgical clip ligation has been proven a safe and durable treatment, endovascular management is emerging as an increasingly popular alternative. The aim of our study is to compare the recovery rate from ONP and assess the safety and long-term durability of both techniques. We have reviewed the retrospective data concerning twenty-two patients treated at our institution between 2004 and 2012 for PcomA aneurysms with ONP. Seven patients were operated on via a standard pterional approach, and fourteen were treated by endovascular occlusion with coils. One patient was managed conservatively. Pre-treatment and post-treatment severity of ONP was recorded, as well as the duration of symptoms before admission and treatment-related complications. All seven patients who underwent surgery improved, with six total recoveries and one partial recovery. Among the fourteen patients treated by embolization, thirteen initially recovered, but long-term follow-up revealed three cases of exacerbation of ONP after refilling of the aneurysms. Two of them were clipped, and one embolized. Also, one partially resolved patient underwent a second embolization. No severe complications occurred in either group. Despite the small number of patients, our study suggests that both surgical clipping and embolization are safe and effective methods in regards to functional recovery (complete ONP recovery in about 85% of the cases). However, coiling may lead to delayed recurrence of third cranial nerve (CN) palsy at long-term follow-up, requiring additional treatment.

Retrieval of Unintended Migrated Detached Coil: Case Report

Owing to the rapid development of intervention techniques and devices, endovascular coil embolization of cerebral arteries has become standardized. It is particularly preferred when a patient presents with an unruptured intracranial aneurysm of the posterior communicating artery (PcomA). However, the risk of thrombogenic complications of the coil migration may also result in a large cerebral infarction.When coil migration occurs during embolization, a procedure for removal of the embolic coil should be performed immediately. We experienced a clinically rare case of migration of a framing coil to the distal middle cerebral artery aneurysm during endovascular embolization of an unruptured PcomA aneurysm. The migrated coil was barely retrieved using snare techniques.

Ptosis as Partial Oculomotor Nerve Palsy Due to Compression by Infundibular Dilatation of Posterior Communicating Artery, Visualized with Three-Dimensional Computer Graphics: Case Report

Oculomotor nerve palsy (ONP) due to internal carotid-posterior communicating artery (PcomA) aneurysm generally manifests as partial nerve palsy including pupillary dysfunction. In contrast, infundibular dilatation (ID) of the PcomA has no pathogenic significance, and mechanical compression of the cranial nerve is extremely rare. We describe a 60-year-old woman who presented with progressive ptosis due to mechanical compression of the oculomotor nerve by an ID of the PcomA. Three-dimensional computer graphics (3DCG) accurately visualized the mechanical compression by the ID, and her ptosis was improved after clipping of the ID. ID of the PcomA may cause ONP by mechanical compression and is treatable surgically. 3DCG are effective for the diagnosis and preoperative simulation.