Management of internal carotid artery bifurcation aneurysm- A clinicoradiological outcome assessment over the last seven years from a tertiary care centre

Management of internal carotid artery bifurcation aneurysm- A clinicoradiological outcome assessment over the last seven years from a tertiary care centre | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Management of internal carotid artery bifurcation aneurysm- A clinicoradiological outcome assessment over the last seven years from a tertiary care centre Ravi Ranjan, Nitish Ranjan, Ved Prakash Maurya, Kamlesh Singh Bhaisora, and 11 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5719155/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Internal Carotid Artery (ICA) bifurcation aneurysms are relatively an uncommon entity. These aneurysm contributes less than 5% of the total intracranial aneurysms in the available literature. They are noticed in relatively younger population and their surgical management poses challenges due to close relation to the terminal branches and perforators in the adjoining area. The present retrospective observational study aims to describe the clinical and radiological nuances in the management of ICA bifurcation aneurysms. Methodology: All the operated cases of aneurysmal subarachnoid hemorrhage (SAH) managed between January 2017 to December 2023 were included. The clinico-radiological scan, including their three-dimensional computerized tomography (3-D CT) of cerebral angiogram was recorded. The intraoperative details of these patients were collected from the neurosurgery operative records. The patients' follow up details were obtained either by the outpatient department or by telephone. Results A total of 33 patients were analysed with a mean age of 44.9 ± 16.5 yrs years. Sudden severe headache and vomiting were the most common presentation. The superomedial orientation 14 (42.4%) was the most common projection of the aneurysm fundus. 27 patients (81.8%) have good outcome (mRS:0–2), six patient (18.2%) had bad outcome (mRS:3–6) and there was no procedure related mortality in this study. The mean follow-up duration was 24.5 ± 4.5 months (range: 8 months to 82 months). Conclusions ICA bifurcation aneurysm are challenging subset of intracranial aneurysms and it requires a detailed neuroanatomical knowledge and 3-dimensional orientation of the ICA anatomy before successful clipping of these aneurysms. Intracranial aneurysm internal carotid artery subarachnoid hemorrhage vasospasm bifurcation aneurysm Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Internal Carotid Artery (ICA) bifurcation aneurysms are rare entity that account for approximately 5% of all intracranial aneurysms. It mostly affects younger patients and are difficult to treat surgically because of the proximity of this region to various perforators [ 1 ]. Exposure of the aneurysm because of its location required frontal lobe retraction which can lead to retraction injury. In this article we attempt to present the clinical outcome of patients harbouring the ICA bifurcation aneurysm managed at a single tertiary centre between January 2017 to December 2023. Methodology This retrospective observational study was conducted in the department of neurosurgery and the study protocols were followed as per the ethical guidelines laid down in the declaration of Helsinki. The clinical, radiological and surgical details of the patients were collected from the Hospital information System and recording keeping system of the department of Neurosurgery during the period of January 2017 to December 2023. The detail operative video recording of the included cases were reviewed to look for the surgical challenges encountered in the clipping of these aneurysms. The follow-up details of these patients over the last seven years were collected from the hospital information and outpatient department record-keeping system ( Fig. 1 . Demonstrating the patient selection process of the study). The latest follow-up of patients were obtained either in the outpatient department of neurosurgery or telephonically. Inclusion Criteria All cases of aneurysmal SAH admitted with clinical characteristics of aneurysmal bleed. Exclusion Criteria Cases of SAH who were detected to have aneurysm other than ICA bifurcation Very poor aneurysmal grade patients who were found not suitable to undergo surgical intervention 1. Clinical Evaluation All patients underwent detailed clinical evaluation, including Glasgow coma scale score, presence of any focal neurological deficits, any cranial nerve palsy; especially third nerve palsy (manifested as ptosis and mydriasis). The clinical grading was used in the form of Hunt and Hess grading and WFNS grading system shown in which are universally accepted and these scales are devoid of significant objective or inter-observer variations. Hunt and Hess grading and Modified WFNS grading are shown in Tables 1 and 2 respectively. Table 1 Table showing the various grades of Hunt and Hess grading system. S.N. Category Criteria 1 Grade I Asymptomatic, or minimal headache and slight nuchal rigidity 2 Grade II Moderate to severe headache, nuchal rigidity, no neurological deficit other than cranial nerve palsy 3 Grade III Drowsiness, confusion, or mild focal deficit 4 Grade IV Stupor, moderate to severe hemiparesis, possibly early decerebrate rigidity and vegetative disturbances. 5 Grade V Deep coma, decerebrate rigidity, moribund appearance Table 2 Table showing the various grades of WFNS grading system. S.N. Grade Criteria 1. Grade I GCS 15 2. Grade II GCS 14 3. Grade III GCS 13 4. Grade IV GCS 7–12 5. Grade V GCS 3–6 2. Radiologic Evaluation and Preoperative Planning The CT brain plain were suggestive of diffuse SAH in the cases of ruptured aneurysmal bleed. The location of the sylvian SAH and lobar hematoma was preliminary suggestive of the laterality of the aneurysmal rupture leading to the SAH in the cisternal spaces. Few of the cases were noticed to have lobar hematoma including the inferomedial surface of the inferior frontal gyrus ( Fig. 2 ). SAH seen on CT brain plain was graded as per Modified Fisher’s Grade which is shown in Table 3 . Modified Fisher grade is also related to incidence of symptomatic vasospasm. Table 3 Table shows the various grades in modified Fisher’ Grading system. S.N. Grade SAH IVH Incidence of Symptomatic Vasospasm 1. 0 No No 0% 2. 1 Focal/Diffuse, Thin No 24% 3. 2 Focal/Diffuse, Thin Yes 33% 4. 3 Thick SAH No 33% 5. 4 Thick SAH Yes 40% The role of CT angiogram and three dimensional (3-D) reconstruction The CT angiogram ( Fig. 3 ) was easily accessible and was done in all the patients found to have SAH with clinical features of severe sudden headache. The CT angiogram were reviewed on the CT scan workstation and following features were noticed in detail. The morphometric relation of the ICA in relation to anterior clinoid process and terminal branches (ACA &MCA): The distance between the anterior clinoid process and the angle between the ACA and MCA were measured in all the case. ( Fig. 4 ) The diameter of the vessels at the bifurcation: The diameter of ICA, ACA (A1) and MCA (M1) were measured at 3 mm from the point of ICA bifurcation. This arbitrary point was chosen to maintain uniformity and avoid inter-observer variability. ( Fig. 4 ) Aneurysm morphology: The morphology of the aneurysm in relation to the neck size, direction of the fundus, lobar hematoma adjacent to the aneurysm, perforator vessel adhered to the neck/ fundus of the aneurysm. Presence of any other aneurysm in the vicinity of the aneurysm. Status of third nerve and optic nerve in relation to the aneurysm. Identification of anterior choroidal artery and posterior communicating artery in 3D- reconstructed images. Feasibility of clipping Vs Endovascular intervention: The size of the neck and width of aneurysm’s fundus were measured to calculate the dome/neck ratio to look for the feasibility of clipping Vs coiling of the aneurysm. The aspect ratio (maximum height of aneurysm fundus/ width of the aneurysm neck), was calculated to predict the chances of aneurysm rupture. 3. Surgical Technique After induction of general anaesthesia and endotracheal intubation, patient was positioned in the supine position with head secured in four pin head fixator system. Head used to be positioned in mild extension so that malar prominence becomes the most prominent point in the operative field. This manoeuvre allows brain to fall away from skull base, minimizing the retraction of brain. The head used to be fixed after 15–20 degree head rotation towards the opposite side with all the pressure points padded to avoid pressure sores. After performing a standard Pterional craniotomy, dura was opened in a curvilinear fashion and reflected anteriorly over the zygoma. Optico carotid and inter-optic cisterns were opened and CSF was released which relaxes the brain. Proper wide splitting of sylvian fissure was recommended from proximal to distal direction to minimise the use of fixed retractor system. Superiorly directed ICA bifurcation aneurysm are commonly adhered to the frontal lobe and can rupture prematurely if frontal lobe retraction is done without proper sylvian splitting. After splitting of sylvian fissure we dissect the ICA vessel till its bifurcation and beyond exposing the initial aspects of A1 and M1 segment. We prefer elective temporary clipping of ICA before final dissection and clipping of the aneurysm neck. This elective temporary clipping prevents premature rupture of aneurysm as well as better visualisation of the relationship between the neck and the surrounding perforators, once the aneurysm became lax following temporary clip application. After clipping of the aneurysm, the surrounding blood clot was washed out with generous saline irrigation and lobar hematoma was evacuated. Injection papaverine used to be instilled in the operative cavity to avoid vasospasm after surgical handling of the vessels. The closure of the wound was performed as per the department policy and patients received standard post-operative care for aneurysm patients. 4. Post operative care and follow up Following surgical clipping all the patients received standard treatment for the post clipping patients in the neurosurgical intensive care unit. The standard euvolemia with hypertension was maintained in all the patients with medication for vasospasm till day 10 of ictus and then gradual tapering of the medications for vasospasm. The patients were observed for onset of any new focal neurological deficits and transcranial doppler was used as an inexpensive tool to help in monitoring of the post operative vasospasm. The patients were followed up as per the standard departmental policy at 6 weeks, 3 months and 6 months. The follow up CT angiogram were performed at 6 weeks of follow up visit. The presence of clipped aneurysm and location of the aneurysm clip was assessed and any additional morbidity in the form of tracheostomy was evaluated for the closure of the stoma if the general condition of the patient allows. The mRS were recorded at each follow up visits and secondary surgical intervention if deemed necessary were performed in the same setting of the visit to the hospital. In case of venous infarct or malignant brain bulge in the post operative period, the patients who were subjected to decompressive craniectomy were subjected to cranioplasty by replacing back the bone flap over the operative site. Results Clinico-Epidemiological Data A total of 33 patients with ruptured ICA bifurcation aneurysm were analysed in this retrospective observational study. Of those, 16 patients (48.5%) were male and 17 patients (51.5%) were female. The study population range from 10 yrs to 70 yrs, mean 44.9 ± 16.5 yrs. Most common symptom was sudden and severe headache which were present in all 33 patients (100%). Other symptoms include vomiting (n = 24,72%), loss of consciousness (n = 10,30.3%), hemiparesis (n = 4,12.12%), seizure (n = 3,0.09%), and aphasia (n = 1,0.03%). Based on the clinical presentation, these patient were classified clinically into Hunt and Hess grade and WFNS grade scale. In this study cohort, using Hunt and Hess grade following was the distribution of patients with SAH: Grade 1: 4 (12.12%) Grade 2: 12 (36.36%) Grade 3: 10 (30.30%) Grade 4: 7 (21.21%) None of the patients belonged to Hunt and Hess grade 5. Upon using WFNS grading scale, following was the distribution of patients with aneurysmal SAH: WFNS grade I: 15 (45.45%) WFNS grade II: 6 (18.18%) WFNS grade III: (15.15%) WFNS grade IV: 7 (21.21%) Radiological Data The CT findings in this study population with aneurysmal SAH were graded using Modified Fisher’s grade scale which is tabulated below in Table 4 . Table 4 Shows Frequency of patients classified into different Modified Fisher Grade S.N. Modified Fisher’s Grade Frequency (%) 1. 0 0 (0%) 2. 1 11 (33.33%) 3. 2 3 (9.09%) 4. 3 14 (42.42%) 5. 4 5 (15.15%) The CT angiogram with 3D reconstructive images of the aneurysmal SAH patients were reviewed to look for the aneurysm morphology. Left ICA bifurcation aneurysm was present in 20 (60.6%) patients while 13 (39.4%) had aneurysm on the right side. The neck size of aneurysm range from 2.5 mm to 6 mm with mean size of 4.3 ± 0.9 mm. Based on the direction of fundus of aneurysm, it was classified into following types which were tabulated in Table 5 . Table 5 Shows frequency of patients based on the direction of aneurysm fundus. S.N. Direction of Fundus Frequency (%) 1. Superomedial 14 (42.4%) 2. Anteromedial 7 (21.2%) 3. Posterolateral 5 (15.1%) 4. Posterosuperior 3 (9.1%) 5. Superolateral 2 (6.1%) 6. Inferomedial 1 (3.0%) 7. Posteromedial 1 (3.0%) The morphometric values and the geometry of ICA bifurcation are described in Table 6 with comparison to control population of 35 patients operated at the our centre who were operated for non-ICA bifurcation aneurysms. There was significant difference in the bifurcation angle between the patients (158.2 ± 8.3 degrees) and the control (142.9 ± 11.1 degrees) group (p < 0.00001). The distance between the anterior clinoid process and the supraclinoid ICA was also significantly higher (p < 0.00001) in the ICA bifurcation aneurysm group (6.4 ± 0.5 mm) than the control population (5.3 ± 1.1 mm). Table 6 Shows the morphometric values of the internal carotid artery and it’s distance from the anterior clinoid process. The ICA bifurcation angle and the lumen diameter of ICA, ACA and MCA. Category Number (N) Distance between anterior clinoid process and supraclinoid ICA [Mean ± S.D.] ICA Bifurcation Angle (between origin of ACA and MCA) [Mean ± S.D.] ICA bifurcation diameter [Mean ± S.D.] ACA origin diameter [Mean ± S.D.] MCA origin diameter [Mean ± S.D.] Case N = 33 6.4 ± 0.5 mm 158.2 ± 8.3 3.4 ± 0.5 mm 1.3 ± 0.1 mm 2.4 ± 0.4 mm Control N = 35 5.3 ± 1.1 mm 142.9 ± 11.1 4.2 ± 1.0 mm 1.6 ± 0.6 mm 2.5 ± 0.5 mm P value < 0.05, significant P < 0.00001 P < 0.00001 P < 0.00063 P < 0.0032 P < 0.5662 Surgical Data All patients underwent Pterional Craniotomy and Clipping of aneurysm. Neck control was not taken in any of the case. There was intra-operative rupture in three (9.1%) patients before adequate aneurysm neck dissection was performed. In the post operative period, significant vasospasm was noticed in 10 (303%) patients and evaluated using transcranial doppler with clinical deterioration. New onset focal neurological deficit were noticed in four (12.1%) patients following clipping of the aneurysm. This deficit was noticed in the immediate post operative period and radiologically new onset hypodensity was present suggestive of perforator injury or perforator getting trapped in the aneurysm clips. Euvolemic hypertension was maintained to overcome the phase of vasospasm. In three patients, fall in GCS was noticed third, fifth and sixth post operative day. The subsequent CT scan of the head was suggestive of gross ischemic infarct in the territory of middle cerebral artery towards the operative side in one patient and hemispheric infarct in the rest of the two patients. These patients underwent re-exploration and decompressive craniectomy was performed to decrease the intracranial pressure and revert the midline shift. These patients did well in the post operative period. Because of prolonged mechanical ventilation and ICU stay eight patients underwent tracheostomy which were closed in the follow visits at six weeks. Outcome, Complications and Follow-up Data Modified Rankin Scale (mRS) was utilised as a tool to evaluate outcome of the cases during post op period at 3 months and at 6 months of follow up. Out of 33 patients, 27 patients (81.8%) have good outcome (mRS:0–2), six patient (18.2%) had bad outcome (mRS:3–6) and there was no procedure related mortality in this study. There was a single mortality after four months of surgery due to respiratory complications. The mRS during the follow-up period are tabulated in a table. The mean follow-up duration was 24.5 ± 4.5 months (range: 8 months to 82 months) Table 7 Table showing the follow-up status of the study cohort at 3 months and 6 months. S.N. Modified Rankin Scale (mRS) At 3 months n (%) At 6 months n (%) 1. 0 6 (18.2%) 8 (24.2%) 2. 1 14 (42.4%) 16 (48.4%) 3. 2 7 (21.2%) 3 (9.1%) 4. 3 2 (6.1%) 2 (6.1%) 5. 4 3 (9.1%) 3 (9.1%) 6. 5 1 (3.0%) 0 (0%) 7. 6 0 (0%) 1 (3.0%) Statistical analysis- Continuous variables are presented in mean with standard deviation and range, whereas categorical variables are presented in number (%). The normality of the data distribution was assessed by using the Kolmogorov- Smirnov test. Student-t- test was used to compare the means between cases and controls. The analyses were performed using the Statistical Package for Social Sciences version- 23 (SPSS-23, IBM, Chicago, USA). P value < 0.05 was considered statistically significant. Discussion Demography and Clinical Profile The internal carotid artery bifurcation aneurysms are known to have relative younger age of occurrence as compared to the aneurysms of other intracranial locations. These aneurysms are known to be associated with some vessel wall disease in addition to the flow dynamics which lead to the vascular dilatation at the area of bifurcation. The present cohort of patients does not follow any gender predilection and nearly two third of the population are within 45 years of age. This age distribution is in accordance to the available literature supporting relative young age of incidence of ICA bifurcation aneurysms [ 2 , 3 ]. Morphology of ICA bifurcation aneurysm As per Miyazawa et al, ICA bifurcation aneurysm is classified by the direction of projection which includes Superior, Anterior, Posterior and Inferior projection [ 3 ]. As per published literature, superior projecting aneurysm are most common and anterior projecting aneurysm is least common which is similar to finding in our study. In our study, most common ICA bifurcation aneurysm is superiorly directed. It is important to know the detail regarding the anatomy of aneurysm especially the projection of aneurysm from the surgical point of view [ 4 , 5 ]. In our study the rate of anterior projection was higher as compared to other studies. The most challenging aneurysm to operate is posteriorly directed ICA bifurcation aneurysm since the perforator density is high and there is high risk of perforator injury. Intracranial hemodynamics The impact of cerebral circulation on the hemodynamics as well as on the lumen of cerebral vasculature is significant resulting in altered flow dynamics. The alteration in vascular flow dynamics becomes more relevant at the areas of significant turbulence and at the areas of vascular bifurcation. The bifurcation of the internal carotid artery is one of the areas of maximum turbulence within the cerebral circulation. This hemodynamic stress has been implicated to be a major contributing factor in the formation, enlargement and further rupture of the intracranial aneurysms. The area of ICA bifurcation of the human cerebral vasculature faces the maximum stress because of the impact of the blood flow, deflection after reaching the bifurcation and subsequent flow separation [ 6 , 7 ]. The vascular geometry at the area of ICA bifurcation, vessels diameter and the angle between the bifurcation branches); also plays a crucial role in the alteration of the hemodynamic stress. Thus, the intracranial hemodynamic stress along with altered vessel wall morphology plays a crucial role in the appearance and progress of the intracranial aneurysm, especially at the areas of the major vascular bifurcation zone. In the study conducted by Akdag R et al (2024), they noticed the α angle (M1–A1), BifA (β + ɣ), P1, and BifSR to be associated with higher incidence of ICA bifurcation aneurysms [ 8 ]. Pathophysiology of bifurcation Aneurysm The tangential force of friction generated by the flowing blood over the arterial wall endothelium leads to the development of Wall shear stress (WSS). Multiple factors associated with the impairment of arterial wall leads to the development of stress and strain in the arterial wall of cerebral vasculature. It has been unanimously accepted that the WSS is the primary hemodynamic factor responsible for the de novo formation of the intracranial aneurysms [ 9 , 10 ]. The WSS is associated with the diameter of the vessel lumen and the angle formed by the parent artery and the arteries at the bifurcation. angle [ 11 ]. The principle of minimum work (PMW) regulate the WSS which in turn is depended upon the vessel diameter and the bifurcation angle [ 12 , 13 ]. The computational flow dynamics using a series of computer studies have concluded that a parent artery with a smaller diameter leads to higher WSS and proportionately higher energy loss at the point of vascular bifurcation [ 14 ]. In our study, majority of the aneurysms were noticed at a relatively younger age with proportionately smaller diameter than the elderly populations. This reflects a positive correlation between the incidence of ICA bifurcation aneurysm and the younger age along with the smaller diameter of the vessels. This observation was supported by the study conducted by ….group showing increased occurrence of aneurysms in the vessels with decreased diameter and was statistically significant (OR, 0.213; 95% CI, 0.084–0.539). Can et al. reported that a reduced cross-sectional area at the bifurcation leads to increased blood velocity and this in turn results into vessel wall changes leading to aneurysm development [ 15 ]. There are studies which support that the ratio between the parent artery’s diameter to the combined diameter of the daughter branches, is not influenced by dimension of the aneurysm [ 16 , 17 ]. Therefore, the lumen diameter of the distal ICA segment may not be the only determinant of aneurysm formation at the bifurcation. Another recent conducted by Cmiel SK et al, reported that the intracranial vessel diameter do not contribute to the PMW. Their comparative study with MCA and BA bifurcations concluded that formation of aneurysms are the result of asymmetrical daughter vessels instead of the relative ratio of vessel diameter [ 9 ]. The angle between the branches of the ICA bifurcation has been studied to draw a correlation between aneurysm occurrence and the BifAn (bifurcation angle). There have been studies supporting the similar theory in the areas of MCA and BA bifurcation aneurysms [ 15 ]. The relationship between the arterial lumen and the hemodynamics play crucial role in the development of aneurysms, since high WSS leads to negative changes in the vascular endothelium. Lauric et al. suggested that patients with narrow bifurcation angle have less WSS gradient and those with wider angle and asymmetric vascular diameter have higher tendency of aneurysm development due to positive WSS gradient [ 18 ]. A recent animal study noticed the similar association between bifurcation angle and aneurysm development [ 19 , 20 ]. Shimuzi et al. in their multicentric centric case control study concluded that a bifurcation angle > 145 degree had a 5.5 times increase in aneurysm progression when compared to a bifurcation anglr of < 145 degree. Boucherti et al.in their multicentric prospective study concluded that bifurcation angle may increase due to the development of intracranial aneurysms [ 21 ]. In the study conducted by Akdag R et al. both alpha (angulation between both daughter vessels) and BifAn (sum of angulation between te parent and daughter vessels) were measured to look for association between ICAbifAn formation. Statistically, alpha angle approached significance [OR, 1.054 (1.026–1.083), p < 0.001]; however, only the BifA angle retained significance after the multivariate analysis [OR, 0.911 (0.877–0.946), p < 0.001]. When values of these angles were subjected to ROC analysis, the BifAn achieved the larger AUC value of 0.81 (compared to alpha angle AUC 0.68), suggesting BifAn as a more accurate predictor of aneurysm formation than alpha angle [ 8 ]. The association of distance of supraclinoid segment of ICA to the ACP was measured in these subset of patients and the control population. The distance was more in the ICA bifurcation group as compared to those with non-ICA bifurcation aneurysm. The distance was more in the ICAb group than those of the control group. This suggests that there exists an unknown relation. Clinical grading and Surgical Management In our study, we graded SAH on CT scan based on modified Fisher Grade based on which it was classified into 5 grades, Grade 0 (0%), Grade 1 (33.33%), Grade II (9.09%), Grade III (42.42%),Grade IV (15.15%). Higher the Fisher grade greater is the chance of symptomatic vasospasm. The first successfully operated case of ICA bifurcation aneurysm was performed by Dott in 1933 where a muscle patch was used to wrap the aneurysm [ 22 ]. Till now more than 40 series have been reported with ICA bifurcation as the central theme [ 3 ]. In our study, 3 patients (9.09%) had intraoperative rupture. In study done by Kwon et al, intraoperative rupture occurred in 5.8% of cases [ 23 , 24 ]. The incidence of vasospasm in our study was 21.21% (7 patients) which were managed medically. In study done by Gupta et al. vasospasm was reported in 24 patients (43.6%) [ 25 ]. Many studies have put the onus on vasospasm for unfavourable outcome, however perforator injury is also cause of poor outcome [ 4 , 26 ]. In study by Kodama et al. post-operative outcome and poor outcome was reported in four cases (13%) secondary to vasospasm. Contrary to this Yasargil et al. concluded that outcome was dictated by clinical grade rather than surgical results [ 27 ]. There were three patients in our study population who developed delayed thromboembolic events leading to significant ischemic stroke and mass effect as a result of this event. This was supposed to be effect of dislodged thrombus and leading to occlusion of distal branches of MCA and causing mass effect. Atherosclerotic disease of the intracranial vessels have been implicated to be a major cause for the delayed onset ischemic stroke in patients undergoing microsurgical clipping of the aneurysms [ 28 , 29 ]. In our series, there were no procedure related mortality. One patient died because of delayed pulmonary complication after four months of discharge from the hospital. Before introduction of micro neurosurgery, mean mortality was around 26.7% but in modern era it has been around 3–5% [ 27 ]. The availability of high end microscopes with better optics and use of microneuroneurosurgical principles have decreased the morbidity and mortality in this complex subset of surgical cases. Limitations Being a retrospective observational study there are certain drawbacks in this study. The vessel wall anatomy could not be analysed in detail nor any further investigations could be performed on these patients to detect the finer details. The smaller sample size is an inherent limitation to this study. To confirm and validate these results of vascular geometry and morphological relation of ICA larger multicentric prospective studies will be required in the future. Conclusion ICA bifurcation aneurysm are challenging subset of intracranial aneurysms and it requires a detailed neuroanatomical knowledge and 3-dimensional orientation of the ICA anatomy before successful clipping of these aneurysms. Altered flow dynamics, the geometry of ICA with its terminal branches and atherosclerotic vessel wall are the triad responsible for the occurrence of this subset of intracranial aneurysm. The atherosclerotic condition is the only modifiable factor which could be considered as the further area of research to mitigate the early insult over the cerebral vasculature. Declarations Funding: The present study does not involve any source of funding. Competing Interest: NIL. Authors contribution: All authors contributed to the study conception and design. Material preparation was done by [Ved Prakash Maurya, Ravi Ranjan], data collection was done by [Ravi Ranjan] , [Ashutosh Kumar], [Shubham Gupta], [Kamlesh Singh Bhaisora], [Kuntal Kanti Das], [Shreyash Rai], [Pawan Kumar Verma], [Soumen Kanjilal], and analysis were performed by [Ved Prakash Maurya], [Anant Mehrotra], [Awadhesh Kumar Jaiswal], [Sanjay Behari], [Devendra Gupta] and [Arun Kumar Srivastava]. The first draft of the manuscript was written by [Ved Prakash Maurya] and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Ethical approval: The present study being a retrospective observational study the Institute Ethics Committee has confirmed that no ethical approval is required to conduct this study. Consent to participate: Informed written consent was obtained from all the participants who were included in the study. 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Neurol Med Chir (Tokyo) 47:153–158 Laranjeira M, Sadasivan B, Ausman JI (1990) Direct surgery for carotid bifurcation artery aneurysms. Surg Neurol 34:250254 Yasargil MG, Boehm WB, Ho RE (1978) Microsurgical treatment of cerebral aneurysms at the bifurcation of the internal carotid artery. Acta Neurochir (Wien) 41:61–72 Pu Y, Lan L, Leng X et al (207) Intracranial atherosclerosis: From anatomy to pathophysiology. International Journal of Stroke 12:236–245 Cebral J, Ollikainen E, Chung BJ et al (2017) Flow Conditions in the Intracranial Aneurysm Lumen Are Associated with Inflammation and Degenerative Changes of the Aneurysm Wall. AJNR Am J Neuroradiol 38:119–126 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5719155","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":394957236,"identity":"ea6daf63-dec6-4db7-9034-554219298134","order_by":0,"name":"Ravi Ranjan","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Ravi","middleName":"","lastName":"Ranjan","suffix":""},{"id":394957237,"identity":"3c71ffaf-fcd7-48ce-95cc-ccccf206d2b0","order_by":1,"name":"Nitish Ranjan","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Nitish","middleName":"","lastName":"Ranjan","suffix":""},{"id":394957238,"identity":"52404d45-8cd0-4445-b5c6-8d69fa8c8edf","order_by":2,"name":"Ved Prakash Maurya","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4klEQVRIiWNgGAWjYHAD5gNAQkKGFC1sCSAtPKRo4TEAkwTVGdzuTv7Mu6dWznxGzudXN2oseBjYDx/dgFfLnbPbpHmeHTeWuZG7zTrnGNBhPGlpN/BpkZyRu42Z58CxxBkSuduMc9iAWiR4zAhp2fwZqKV+hkTOM+Ocf0Ro4ZfI3SDNc6AmQUIih/lxbhsxWmTObpOcc+CA4QyeZ2bMuX0SPGyE/MIm3bv5w5sDdfIS7MmPP+d8q5PjZz98DK8WBgkweZiBQSCBDcxmw6scoaUO6MQDzB8Iqh4Fo2AUjIIRCQBBUUcFVtyiMQAAAABJRU5ErkJggg==","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":true,"prefix":"","firstName":"Ved","middleName":"Prakash","lastName":"Maurya","suffix":""},{"id":394957239,"identity":"c2cdc1a8-f113-48a2-8557-d80bed5d45a3","order_by":3,"name":"Kamlesh Singh Bhaisora","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Kamlesh","middleName":"Singh","lastName":"Bhaisora","suffix":""},{"id":394957240,"identity":"7e0be4f9-e0ee-4d2b-a641-6ce3d5f62ba9","order_by":4,"name":"Arun K Srivastava","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Arun","middleName":"K","lastName":"Srivastava","suffix":""},{"id":394957241,"identity":"2375b643-2fac-473d-94be-5ef9f2479b25","order_by":5,"name":"Kuntal K Das","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Kuntal","middleName":"K","lastName":"Das","suffix":""},{"id":394957242,"identity":"89866288-3bfe-4072-83cc-448470aeca79","order_by":6,"name":"Shreyash Rai","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Shreyash","middleName":"","lastName":"Rai","suffix":""},{"id":394957243,"identity":"f2ec44c8-b8a5-488b-9cbf-217282981555","order_by":7,"name":"Shubham Gupta","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Shubham","middleName":"","lastName":"Gupta","suffix":""},{"id":394957244,"identity":"dc4f9d05-06a2-4433-9abc-84463697b874","order_by":8,"name":"Soumen Kanjilal","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Soumen","middleName":"","lastName":"Kanjilal","suffix":""},{"id":394957245,"identity":"b7dd7198-9c1d-4a34-9763-05c7234ab92f","order_by":9,"name":"Pawan KVerma","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Pawan","middleName":"","lastName":"KVerma","suffix":""},{"id":394957246,"identity":"f7cbffcd-3c2a-49c7-9772-9c03ac649fe0","order_by":10,"name":"Ashutosh Kumar","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Ashutosh","middleName":"","lastName":"Kumar","suffix":""},{"id":394957247,"identity":"b970a248-27a6-4491-bd96-3a1f88f58fa8","order_by":11,"name":"Anant Mehrotra","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Anant","middleName":"","lastName":"Mehrotra","suffix":""},{"id":394957248,"identity":"c376bebe-e8a0-4956-a166-d15a71545fe6","order_by":12,"name":"Awadhesh Jaiswal","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Awadhesh","middleName":"","lastName":"Jaiswal","suffix":""},{"id":394957249,"identity":"8336948e-33ee-46c7-b78b-df79089070ca","order_by":13,"name":"Devendra Gupta","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Devendra","middleName":"","lastName":"Gupta","suffix":""},{"id":394957250,"identity":"82ff1c45-1b73-4d50-acf0-2018b422499b","order_by":14,"name":"Sanjay Behari","email":"","orcid":"","institution":"Sanjay Gandhi Post Graduate Institute of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Sanjay","middleName":"","lastName":"Behari","suffix":""}],"badges":[],"createdAt":"2024-12-27 05:38:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5719155/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5719155/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":72643855,"identity":"ae4462a3-08f0-47a3-9f07-db2fbdbae20f","added_by":"auto","created_at":"2024-12-30 16:38:41","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":150161,"visible":true,"origin":"","legend":"\u003cp\u003eThe figure shows the consort diagram showing the selection of the cases for the study.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5719155/v1/a5fa2854eee84a72fe5a2d02.jpeg"},{"id":72643856,"identity":"473e11d8-6b00-41d0-aa7a-73ea763267be","added_by":"auto","created_at":"2024-12-30 16:38:41","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":120257,"visible":true,"origin":"","legend":"\u003cp\u003eFigure demonstrating the CT brain plain showing a) cisternal bleed, b) bleed in inferomedial surface of inferior frontal lobe.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5719155/v1/85319fdbf9fa71bfc4132e90.jpeg"},{"id":72645902,"identity":"3d421215-c254-4ad7-8dfa-b5ada1560a7c","added_by":"auto","created_at":"2024-12-30 16:46:43","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":199073,"visible":true,"origin":"","legend":"\u003cp\u003eThe CT angiogram showing a) MIP image showing right side ICA bifurcation aneurysm, b) 3-D reconstruction image showing ICA bifurcation aneurysm (black arrow) and c) 3-D reconstruction image showing ICA bifurcation aneurysm (red arrow).\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5719155/v1/a77f2e60f9c3695afb76c5b1.jpeg"},{"id":72643955,"identity":"9de5a044-1728-41c0-aaff-c2fb6b3f1d0a","added_by":"auto","created_at":"2024-12-30 16:38:43","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1046731,"visible":true,"origin":"","legend":"\u003cp\u003eThe figure demonstrated the 3-D reconstruction images of ICA bifurcation aneurysm. a. Demonstrates the vessel diameter of the bifurcation branches, anterior cerebral artery, (ACA, A1) and middle cerebral artery, (MCA, M1). b. Demonstrates the measurement of bifurcation angle between the two terminal branches of ICA, between ACA and MCA. c. Demonstrates the distance between the anterior clinoid process and the supraclinoid portion of the ICA.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-5719155/v1/f8dc3ac818912753e5a1008a.png"},{"id":75242359,"identity":"bef33e90-5e33-44ed-b0a8-ed2fc4872a03","added_by":"auto","created_at":"2025-02-01 22:16:25","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2969061,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5719155/v1/49331778-51aa-4924-a4db-bffb98d57fbb.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Management of internal carotid artery bifurcation aneurysm- A clinicoradiological outcome assessment over the last seven years from a tertiary care centre","fulltext":[{"header":"Introduction","content":"\u003cp\u003eInternal Carotid Artery (ICA) bifurcation aneurysms are rare entity that account for approximately 5% of all intracranial aneurysms. It mostly affects younger patients and are difficult to treat surgically because of the proximity of this region to various perforators [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Exposure of the aneurysm because of its location required frontal lobe retraction which can lead to retraction injury. In this article we attempt to present the clinical outcome of patients harbouring the ICA bifurcation aneurysm managed at a single tertiary centre between January 2017 to December 2023.\u003c/p\u003e"},{"header":"Methodology","content":"\u003cp\u003eThis retrospective observational study was conducted in the department of neurosurgery and the study protocols were followed as per the ethical guidelines laid down in the declaration of Helsinki. The clinical, radiological and surgical details of the patients were collected from the Hospital information System and recording keeping system of the department of Neurosurgery during the period of January 2017 to December 2023. The detail operative video recording of the included cases were reviewed to look for the surgical challenges encountered in the clipping of these aneurysms. The follow-up details of these patients over the last seven years were collected from the hospital information and outpatient department record-keeping system \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Demonstrating the patient selection process of the study). The latest follow-up of patients were obtained either in the outpatient department of neurosurgery or telephonically.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eInclusion Criteria\u003c/h2\u003e \u003cp\u003eAll cases of aneurysmal SAH admitted with clinical characteristics of aneurysmal bleed.\u003c/p\u003e \u003cp\u003e \u003cb\u003eExclusion Criteria\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eCases of SAH who were detected to have aneurysm other than ICA bifurcation\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eVery poor aneurysmal grade patients who were found not suitable to undergo surgical intervention\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003e1. Clinical Evaluation\u003c/h3\u003e\n\u003cp\u003eAll patients underwent detailed clinical evaluation, including Glasgow coma scale score, presence of any focal neurological deficits, any cranial nerve palsy; especially third nerve palsy (manifested as ptosis and mydriasis). The clinical grading was used in the form of Hunt and Hess grading and WFNS grading system shown in which are universally accepted and these scales are devoid of significant objective or inter-observer variations. Hunt and Hess grading and Modified WFNS grading are shown in Tables\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e respectively.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTable showing the various grades of Hunt and Hess grading system.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS.N.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCategory\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCriteria\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAsymptomatic, or minimal headache and slight nuchal rigidity\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eModerate to severe headache, nuchal rigidity, no neurological deficit other than cranial nerve palsy\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDrowsiness, confusion, or mild focal deficit\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade IV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStupor, moderate to severe hemiparesis, possibly early decerebrate rigidity and vegetative disturbances.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDeep coma, decerebrate rigidity, moribund appearance\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTable showing the various grades of WFNS grading system.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS.N.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCriteria\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGCS 15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGCS 14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGCS 13\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade IV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGCS 7\u0026ndash;12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGCS 3\u0026ndash;6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003e2. Radiologic Evaluation and Preoperative Planning\u003c/h3\u003e\n\u003cp\u003eThe CT brain plain were suggestive of diffuse SAH in the cases of ruptured aneurysmal bleed. The location of the sylvian SAH and lobar hematoma was preliminary suggestive of the laterality of the aneurysmal rupture leading to the SAH in the cisternal spaces. Few of the cases were noticed to have lobar hematoma including the inferomedial surface of the inferior frontal gyrus \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e).\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSAH seen on CT brain plain was graded as per Modified Fisher\u0026rsquo;s Grade which is shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Modified Fisher grade is also related to incidence of symptomatic vasospasm.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTable shows the various grades in modified Fisher\u0026rsquo; Grading system.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS.N.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrade\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSAH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eIVH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIncidence of Symptomatic Vasospasm\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFocal/Diffuse, Thin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e24%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFocal/Diffuse, Thin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eThick SAH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eThick SAH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e40%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003eThe role of CT angiogram and three dimensional (3-D) reconstruction\u003c/h3\u003e\n\u003cp\u003eThe CT angiogram \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e was easily accessible and was done in all the patients found to have SAH with clinical features of severe sudden headache. The CT angiogram were reviewed on the CT scan workstation and following features were noticed in detail.\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eThe morphometric relation of the ICA in relation to anterior clinoid process and terminal branches (ACA \u0026amp;MCA): The distance between the anterior clinoid process and the angle between the ACA and MCA were measured in all the case. \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eThe diameter of the vessels at the bifurcation: The diameter of ICA, ACA (A1) and MCA (M1) were measured at 3 mm from the point of ICA bifurcation. This arbitrary point was chosen to maintain uniformity and avoid inter-observer variability. \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAneurysm morphology: The morphology of the aneurysm in relation to the neck size, direction of the fundus, lobar hematoma adjacent to the aneurysm, perforator vessel adhered to the neck/ fundus of the aneurysm. Presence of any other aneurysm in the vicinity of the aneurysm. Status of third nerve and optic nerve in relation to the aneurysm. Identification of anterior choroidal artery and posterior communicating artery in 3D- reconstructed images.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eFeasibility of clipping Vs Endovascular intervention: The size of the neck and width of aneurysm\u0026rsquo;s fundus were measured to calculate the dome/neck ratio to look for the feasibility of clipping Vs coiling of the aneurysm. The aspect ratio (maximum height of aneurysm fundus/ width of the aneurysm neck), was calculated to predict the chances of aneurysm rupture.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003e3. Surgical Technique\u003c/h3\u003e\n\u003cp\u003eAfter induction of general anaesthesia and endotracheal intubation, patient was positioned in the supine position with head secured in four pin head fixator system. Head used to be positioned in mild extension so that malar prominence becomes the most prominent point in the operative field. This manoeuvre allows brain to fall away from skull base, minimizing the retraction of brain. The head used to be fixed after 15\u0026ndash;20 degree head rotation towards the opposite side with all the pressure points padded to avoid pressure sores.\u003c/p\u003e \u003cp\u003eAfter performing a standard Pterional craniotomy, dura was opened in a curvilinear fashion and reflected anteriorly over the zygoma. Optico carotid and inter-optic cisterns were opened and CSF was released which relaxes the brain. Proper wide splitting of sylvian fissure was recommended from proximal to distal direction to minimise the use of fixed retractor system. Superiorly directed ICA bifurcation aneurysm are commonly adhered to the frontal lobe and can rupture prematurely if frontal lobe retraction is done without proper sylvian splitting. After splitting of sylvian fissure we dissect the ICA vessel till its bifurcation and beyond exposing the initial aspects of A1 and M1 segment.\u003c/p\u003e \u003cp\u003eWe prefer elective temporary clipping of ICA before final dissection and clipping of the aneurysm neck. This elective temporary clipping prevents premature rupture of aneurysm as well as better visualisation of the relationship between the neck and the surrounding perforators, once the aneurysm became lax following temporary clip application. After clipping of the aneurysm, the surrounding blood clot was washed out with generous saline irrigation and lobar hematoma was evacuated. Injection papaverine used to be instilled in the operative cavity to avoid vasospasm after surgical handling of the vessels. The closure of the wound was performed as per the department policy and patients received standard post-operative care for aneurysm patients.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e4. Post operative care and follow up\u003c/h2\u003e \u003cp\u003eFollowing surgical clipping all the patients received standard treatment for the post clipping patients in the neurosurgical intensive care unit. The standard euvolemia with hypertension was maintained in all the patients with medication for vasospasm till day 10 of ictus and then gradual tapering of the medications for vasospasm. The patients were observed for onset of any new focal neurological deficits and transcranial doppler was used as an inexpensive tool to help in monitoring of the post operative vasospasm.\u003c/p\u003e \u003cp\u003eThe patients were followed up as per the standard departmental policy at 6 weeks, 3 months and 6 months. The follow up CT angiogram were performed at 6 weeks of follow up visit. The presence of clipped aneurysm and location of the aneurysm clip was assessed and any additional morbidity in the form of tracheostomy was evaluated for the closure of the stoma if the general condition of the patient allows. The mRS were recorded at each follow up visits and secondary surgical intervention if deemed necessary were performed in the same setting of the visit to the hospital.\u003c/p\u003e \u003cp\u003eIn case of venous infarct or malignant brain bulge in the post operative period, the patients who were subjected to decompressive craniectomy were subjected to cranioplasty by replacing back the bone flap over the operative site.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eClinico-Epidemiological Data\u003c/h2\u003e \u003cp\u003eA total of 33 patients with ruptured ICA bifurcation aneurysm were analysed in this retrospective observational study. Of those, 16 patients (48.5%) were male and 17 patients (51.5%) were female. The study population range from 10 yrs to 70 yrs, mean 44.9\u0026thinsp;\u0026plusmn;\u0026thinsp;16.5 yrs. Most common symptom was sudden and severe headache which were present in all 33 patients (100%). Other symptoms include vomiting (n\u0026thinsp;=\u0026thinsp;24,72%), loss of consciousness (n\u0026thinsp;=\u0026thinsp;10,30.3%), hemiparesis (n\u0026thinsp;=\u0026thinsp;4,12.12%), seizure (n\u0026thinsp;=\u0026thinsp;3,0.09%), and aphasia (n\u0026thinsp;=\u0026thinsp;1,0.03%). Based on the clinical presentation, these patient were classified clinically into Hunt and Hess grade and WFNS grade scale.\u003c/p\u003e \u003cp\u003eIn this study cohort, using Hunt and Hess grade following was the distribution of patients with SAH:\u003c/p\u003e \u003cp\u003eGrade 1: 4 (12.12%)\u003c/p\u003e \u003cp\u003eGrade 2: 12 (36.36%)\u003c/p\u003e \u003cp\u003eGrade 3: 10 (30.30%)\u003c/p\u003e \u003cp\u003eGrade 4: 7 (21.21%)\u003c/p\u003e \u003cp\u003eNone of the patients belonged to Hunt and Hess grade 5.\u003c/p\u003e \u003cp\u003eUpon using WFNS grading scale, following was the distribution of patients with aneurysmal SAH:\u003c/p\u003e \u003cp\u003eWFNS grade I: 15 (45.45%)\u003c/p\u003e \u003cp\u003eWFNS grade II: 6 (18.18%)\u003c/p\u003e \u003cp\u003eWFNS grade III: (15.15%)\u003c/p\u003e \u003cp\u003eWFNS grade IV: 7 (21.21%)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eRadiological Data\u003c/h2\u003e \u003cp\u003eThe CT findings in this study population with aneurysmal SAH were graded using Modified Fisher\u0026rsquo;s grade scale which is tabulated below in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eShows Frequency of patients classified into different Modified Fisher Grade\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS.N.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModified Fisher\u0026rsquo;s Grade\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFrequency (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11 (33.33%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (9.09%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (42.42%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (15.15%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe CT angiogram with 3D reconstructive images of the aneurysmal SAH patients were reviewed to look for the aneurysm morphology. Left ICA bifurcation aneurysm was present in 20 (60.6%) patients while 13 (39.4%) had aneurysm on the right side. The neck size of aneurysm range from 2.5 mm to 6 mm with mean size of 4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 mm. Based on the direction of fundus of aneurysm, it was classified into following types which were tabulated in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eShows frequency of patients based on the direction of aneurysm fundus.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS.N.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDirection of Fundus\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFrequency (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSuperomedial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14 (42.4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAnteromedial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7 (21.2%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePosterolateral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5 (15.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePosterosuperior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3 (9.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSuperolateral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2 (6.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInferomedial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1 (3.0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePosteromedial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1 (3.0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe morphometric values and the geometry of ICA bifurcation are described in Table \u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e with comparison to control population of 35 patients operated at the our centre who were operated for non-ICA bifurcation aneurysms. There was significant difference in the bifurcation angle between the patients (158.2\u0026thinsp;\u0026plusmn;\u0026thinsp;8.3 degrees) and the control (142.9\u0026thinsp;\u0026plusmn;\u0026thinsp;11.1 degrees) group (p\u0026thinsp;\u0026lt;\u0026thinsp;0.00001). The distance between the anterior clinoid process and the supraclinoid ICA was also significantly higher (p\u0026thinsp;\u0026lt;\u0026thinsp;0.00001) in the ICA bifurcation aneurysm group (6.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 mm) than the control population (5.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1 mm).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eShows the morphometric values of the internal carotid artery and it\u0026rsquo;s distance from the anterior clinoid process. The ICA bifurcation angle and the lumen diameter of ICA, ACA and MCA.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCategory\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNumber (N)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDistance between anterior clinoid process and supraclinoid ICA [Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;S.D.]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eICA Bifurcation Angle (between origin of ACA and MCA) [Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;S.D.]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eICA bifurcation diameter [Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;S.D.]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eACA origin diameter [Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;S.D.]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMCA origin diameter [Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;S.D.]\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCase\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e158.2\u0026thinsp;\u0026plusmn;\u0026thinsp;8.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4 mm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e142.9\u0026thinsp;\u0026plusmn;\u0026thinsp;11.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 mm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eP value\u0026thinsp;\u0026lt;\u0026thinsp;0.05, significant\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.00001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.00001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.00063\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.0032\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eP\u0026thinsp;\u0026lt;\u0026thinsp;0.5662\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eSurgical Data\u003c/h2\u003e \u003cp\u003eAll patients underwent Pterional Craniotomy and Clipping of aneurysm. Neck control was not taken in any of the case. There was intra-operative rupture in three (9.1%) patients before adequate aneurysm neck dissection was performed. In the post operative period, significant vasospasm was noticed in 10 (303%) patients and evaluated using transcranial doppler with clinical deterioration. New onset focal neurological deficit were noticed in four (12.1%) patients following clipping of the aneurysm. This deficit was noticed in the immediate post operative period and radiologically new onset hypodensity was present suggestive of perforator injury or perforator getting trapped in the aneurysm clips. Euvolemic hypertension was maintained to overcome the phase of vasospasm.\u003c/p\u003e \u003cp\u003eIn three patients, fall in GCS was noticed third, fifth and sixth post operative day. The subsequent CT scan of the head was suggestive of gross ischemic infarct in the territory of middle cerebral artery towards the operative side in one patient and hemispheric infarct in the rest of the two patients. These patients underwent re-exploration and decompressive craniectomy was performed to decrease the intracranial pressure and revert the midline shift. These patients did well in the post operative period. Because of prolonged mechanical ventilation and ICU stay eight patients underwent tracheostomy which were closed in the follow visits at six weeks.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eOutcome, Complications and Follow-up Data\u003c/h2\u003e \u003cp\u003eModified Rankin Scale (mRS) was utilised as a tool to evaluate outcome of the cases during post op period at 3 months and at 6 months of follow up. Out of 33 patients, 27 patients (81.8%) have good outcome (mRS:0\u0026ndash;2), six patient (18.2%) had bad outcome (mRS:3\u0026ndash;6) and there was no procedure related mortality in this study. There was a single mortality after four months of surgery due to respiratory complications. The mRS during the follow-up period are tabulated in a table. The mean follow-up duration was 24.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.5 months (range: 8 months to 82 months)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTable showing the follow-up status of the study cohort at 3 months and 6 months.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS.N.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModified Rankin Scale (mRS)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAt 3 months\u003c/p\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAt 6 months\u003c/p\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (18.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8 (24.2%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (42.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16 (48.4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (21.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (9.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (6.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (6.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (9.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (9.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (3.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (3.0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eStatistical analysis-\u003c/b\u003e Continuous variables are presented in mean with standard deviation and range, whereas categorical variables are presented in number (%). The normality of the data distribution was assessed by using the Kolmogorov- Smirnov test. Student-t- test was used to compare the means between cases and controls. The analyses were performed using the Statistical Package for Social Sciences version- 23 (SPSS-23, IBM, Chicago, USA). P value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eDemography and Clinical Profile\u003c/h2\u003e \u003cp\u003eThe internal carotid artery bifurcation aneurysms are known to have relative younger age of occurrence as compared to the aneurysms of other intracranial locations. These aneurysms are known to be associated with some vessel wall disease in addition to the flow dynamics which lead to the vascular dilatation at the area of bifurcation. The present cohort of patients does not follow any gender predilection and nearly two third of the population are within 45 years of age. This age distribution is in accordance to the available literature supporting relative young age of incidence of ICA bifurcation aneurysms [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eMorphology of ICA bifurcation aneurysm\u003c/h2\u003e \u003cp\u003eAs per Miyazawa et al, ICA bifurcation aneurysm is classified by the direction of projection which includes Superior, Anterior, Posterior and Inferior projection [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. As per published literature, superior projecting aneurysm are most common and anterior projecting aneurysm is least common which is similar to finding in our study. In our study, most common ICA bifurcation aneurysm is superiorly directed. It is important to know the detail regarding the anatomy of aneurysm especially the projection of aneurysm from the surgical point of view [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In our study the rate of anterior projection was higher as compared to other studies. The most challenging aneurysm to operate is posteriorly directed ICA bifurcation aneurysm since the perforator density is high and there is high risk of perforator injury.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eIntracranial hemodynamics\u003c/h2\u003e \u003cp\u003eThe impact of cerebral circulation on the hemodynamics as well as on the lumen of cerebral vasculature is significant resulting in altered flow dynamics. The alteration in vascular flow dynamics becomes more relevant at the areas of significant turbulence and at the areas of vascular bifurcation. The bifurcation of the internal carotid artery is one of the areas of maximum turbulence within the cerebral circulation. This hemodynamic stress has been implicated to be a major contributing factor in the formation, enlargement and further rupture of the intracranial aneurysms. The area of ICA bifurcation of the human cerebral vasculature faces the maximum stress because of the impact of the blood flow, deflection after reaching the bifurcation and subsequent flow separation [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The vascular geometry at the area of ICA bifurcation, vessels diameter and the angle between the bifurcation branches); also plays a crucial role in the alteration of the hemodynamic stress. Thus, the intracranial hemodynamic stress along with altered vessel wall morphology plays a crucial role in the appearance and progress of the intracranial aneurysm, especially at the areas of the major vascular bifurcation zone. In the study conducted by Akdag R et al (2024), they noticed the α angle (M1\u0026ndash;A1), BifA (β + ɣ), P1, and BifSR to be associated with higher incidence of ICA bifurcation aneurysms [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003ePathophysiology of bifurcation Aneurysm\u003c/h2\u003e \u003cp\u003eThe tangential force of friction generated by the flowing blood over the arterial wall endothelium leads to the development of Wall shear stress (WSS). Multiple factors associated with the impairment of arterial wall leads to the development of stress and strain in the arterial wall of cerebral vasculature. It has been unanimously accepted that the WSS is the primary hemodynamic factor responsible for the de novo formation of the intracranial aneurysms [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe WSS is associated with the diameter of the vessel lumen and the angle formed by the parent artery and the arteries at the bifurcation. angle [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The principle of minimum work (PMW) regulate the WSS which in turn is depended upon the vessel diameter and the bifurcation angle [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The computational flow dynamics using a series of computer studies have concluded that a parent artery with a smaller diameter leads to higher WSS and proportionately higher energy loss at the point of vascular bifurcation [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. In our study, majority of the aneurysms were noticed at a relatively younger age with proportionately smaller diameter than the elderly populations. This reflects a positive correlation between the incidence of ICA bifurcation aneurysm and the younger age along with the smaller diameter of the vessels.\u003c/p\u003e \u003cp\u003eThis observation was supported by the study conducted by \u0026hellip;.group showing increased occurrence of aneurysms in the vessels with decreased diameter and was statistically significant (OR, 0.213; 95% CI, 0.084\u0026ndash;0.539). Can et al. reported that a reduced cross-sectional area at the bifurcation leads to increased blood velocity and this in turn results into vessel wall changes leading to aneurysm development [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. There are studies which support that the ratio between the parent artery\u0026rsquo;s diameter to the combined diameter of the daughter branches, is not influenced by dimension of the aneurysm [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Therefore, the lumen diameter of the distal ICA segment may not be the only determinant of aneurysm formation at the bifurcation.\u003c/p\u003e \u003cp\u003eAnother recent conducted by Cmiel SK et al, reported that the intracranial vessel diameter do not contribute to the PMW. Their comparative study with MCA and BA bifurcations concluded that formation of aneurysms are the result of asymmetrical daughter vessels instead of the relative ratio of vessel diameter [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe angle between the branches of the ICA bifurcation has been studied to draw a correlation between aneurysm occurrence and the BifAn (bifurcation angle). There have been studies supporting the similar theory in the areas of MCA and BA bifurcation aneurysms [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The relationship between the arterial lumen and the hemodynamics play crucial role in the development of aneurysms, since high WSS leads to negative changes in the vascular endothelium. Lauric et al. suggested that patients with narrow bifurcation angle have less WSS gradient and those with wider angle and asymmetric vascular diameter have higher tendency of aneurysm development due to positive WSS gradient [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. A recent animal study noticed the similar association between bifurcation angle and aneurysm development [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Shimuzi et al. in their multicentric centric case control study concluded that a bifurcation angle\u0026thinsp;\u0026gt;\u0026thinsp;145 degree had a 5.5 times increase in aneurysm progression when compared to a bifurcation anglr of \u0026lt;\u0026thinsp;145 degree. Boucherti et al.in their multicentric prospective study concluded that bifurcation angle may increase due to the development of intracranial aneurysms [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. In the study conducted by Akdag R et al. both alpha (angulation between both daughter vessels) and BifAn (sum of angulation between te parent and daughter vessels) were measured to look for association between ICAbifAn formation. Statistically, alpha angle approached significance [OR, 1.054 (1.026\u0026ndash;1.083), \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001]; however, only the BifA angle retained significance after the multivariate analysis [OR, 0.911 (0.877\u0026ndash;0.946), \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001]. When values of these angles were subjected to ROC analysis, the BifAn achieved the larger AUC value of 0.81 (compared to alpha angle AUC 0.68), suggesting BifAn as a more accurate predictor of aneurysm formation than alpha angle [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe association of distance of supraclinoid segment of ICA to the ACP was measured in these subset of patients and the control population. The distance was more in the ICA bifurcation group as compared to those with non-ICA bifurcation aneurysm. The distance was more in the ICAb group than those of the control group. This suggests that there exists an unknown relation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003eClinical grading and Surgical Management\u003c/h2\u003e \u003cp\u003eIn our study, we graded SAH on CT scan based on modified Fisher Grade based on which it was classified into 5 grades, Grade 0 (0%), Grade 1 (33.33%), Grade II (9.09%), Grade III (42.42%),Grade IV (15.15%). Higher the Fisher grade greater is the chance of symptomatic vasospasm. The first successfully operated case of ICA bifurcation aneurysm was performed by Dott in 1933 where a muscle patch was used to wrap the aneurysm [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Till now more than 40 series have been reported with ICA bifurcation as the central theme [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn our study, 3 patients (9.09%) had intraoperative rupture. In study done by Kwon et al, intraoperative rupture occurred in 5.8% of cases [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The incidence of vasospasm in our study was 21.21% (7 patients) which were managed medically. In study done by Gupta et al. vasospasm was reported in 24 patients (43.6%) [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Many studies have put the onus on vasospasm for unfavourable outcome, however perforator injury is also cause of poor outcome [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. In study by Kodama et al. post-operative outcome and poor outcome was reported in four cases (13%) secondary to vasospasm. Contrary to this Yasargil et al. concluded that outcome was dictated by clinical grade rather than surgical results [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThere were three patients in our study population who developed delayed thromboembolic events leading to significant ischemic stroke and mass effect as a result of this event. This was supposed to be effect of dislodged thrombus and leading to occlusion of distal branches of MCA and causing mass effect. Atherosclerotic disease of the intracranial vessels have been implicated to be a major cause for the delayed onset ischemic stroke in patients undergoing microsurgical clipping of the aneurysms [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn our series, there were no procedure related mortality. One patient died because of delayed pulmonary complication after four months of discharge from the hospital. Before introduction of micro neurosurgery, mean mortality was around 26.7% but in modern era it has been around 3\u0026ndash;5% [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The availability of high end microscopes with better optics and use of microneuroneurosurgical principles have decreased the morbidity and mortality in this complex subset of surgical cases.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eBeing a retrospective observational study there are certain drawbacks in this study. The vessel wall anatomy could not be analysed in detail nor any further investigations could be performed on these patients to detect the finer details. The smaller sample size is an inherent limitation to this study. To confirm and validate these results of vascular geometry and morphological relation of ICA larger multicentric prospective studies will be required in the future.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003e \u003cb\u003eICA\u003c/b\u003e bifurcation aneurysm are challenging subset of intracranial aneurysms and it requires a detailed neuroanatomical knowledge and 3-dimensional orientation of the ICA anatomy before successful clipping of these aneurysms. Altered flow dynamics, the geometry of ICA with its terminal branches and atherosclerotic vessel wall are the triad responsible for the occurrence of this subset of intracranial aneurysm. The atherosclerotic condition is the only modifiable factor which could be considered as the further area of research to mitigate the early insult over the cerebral vasculature.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eThe present study does not involve any source of funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interest: NIL.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors contribution:\u0026nbsp;\u003c/strong\u003eAll authors contributed to the study conception and design. Material preparation was done by [Ved Prakash Maurya, Ravi Ranjan], \u0026nbsp; data collection was done by [Ravi Ranjan] , [Ashutosh Kumar], [Shubham Gupta], [Kamlesh Singh Bhaisora], [Kuntal Kanti Das], [Shreyash Rai], [Pawan Kumar Verma], [Soumen Kanjilal],\u0026nbsp;and analysis were performed by [Ved Prakash Maurya], [Anant Mehrotra], [Awadhesh Kumar Jaiswal], [Sanjay Behari], [Devendra Gupta] and [Arun Kumar Srivastava].\u0026nbsp;The first draft of the manuscript was written by [Ved Prakash Maurya] and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval:\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eThe present study being a retrospective observational study the Institute Ethics Committee has confirmed that no ethical approval is required to conduct this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate:\u003c/strong\u003e Informed written consent was obtained from all the participants who were included in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to publish:\u0026nbsp;\u003c/strong\u003eThe\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eauthors affirm that human research participants provided informed consent for publication of the radiological and surgical images displayed in Figure 2, Figures 3 and Figure 4.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement:\u003c/strong\u003e No one to acknowledge.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest:\u003c/strong\u003e The authors have no conflict of interest to declare.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eVlak MH, Algra A, Brandenburg R et al (2011) Prevalence of unruptured intracranial aneurysms, with emphasis on sex, age, comorbidity, country, and time period: A systematic review and meta-analysis. Lancet Neurol 10:626\u0026ndash;636\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRinkel GJE, Djibuti M, Algra A et al (1998) Prevalence and risk of rupture of intracranial aneurysms. Stroke 29:251. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003edoi.org/10.1161/01.STR.29.1.251\u003c/span\u003e\u003cspan address=\"10.1161/01.STR.29.1.251\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMiyazawa N, Nukui H, Horikoshi T et al (2002) Surgical management of aneurysms of the bifurcation of the internal carotid artery. 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AJNR Am J Neuroradiol 38:119\u0026ndash;126\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Intracranial aneurysm, internal carotid artery, subarachnoid hemorrhage, vasospasm, bifurcation aneurysm","lastPublishedDoi":"10.21203/rs.3.rs-5719155/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5719155/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eInternal Carotid Artery (ICA) bifurcation aneurysms are relatively an uncommon entity. These aneurysm contributes less than 5% of the total intracranial aneurysms in the available literature. They are noticed in relatively younger population and their surgical management poses challenges due to close relation to the terminal branches and perforators in the adjoining area. The present retrospective observational study aims to describe the clinical and radiological nuances in the management of ICA bifurcation aneurysms.\u003c/p\u003e\u003ch2\u003eMethodology:\u003c/h2\u003e \u003cp\u003eAll the operated cases of aneurysmal subarachnoid hemorrhage (SAH) managed between January 2017 to December 2023 were included. The clinico-radiological scan, including their three-dimensional computerized tomography (3-D CT) of cerebral angiogram was recorded. The intraoperative details of these patients were collected from the neurosurgery operative records. The patients' follow up details were obtained either by the outpatient department or by telephone.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eA total of 33 patients were analysed with a mean age of 44.9\u0026thinsp;\u0026plusmn;\u0026thinsp;16.5 yrs years. Sudden severe headache and vomiting were the most common presentation. The superomedial orientation 14 (42.4%) was the most common projection of the aneurysm fundus. 27 patients (81.8%) have good outcome (mRS:0\u0026ndash;2), six patient (18.2%) had bad outcome (mRS:3\u0026ndash;6) and there was no procedure related mortality in this study. The mean follow-up duration was 24.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.5 months (range: 8 months to 82 months).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003e \u003cb\u003eICA\u003c/b\u003e bifurcation aneurysm are challenging subset of intracranial aneurysms and it requires a detailed neuroanatomical knowledge and 3-dimensional orientation of the ICA anatomy before successful clipping of these aneurysms.\u003c/p\u003e","manuscriptTitle":"Management of internal carotid artery bifurcation aneurysm- A clinicoradiological outcome assessment over the last seven years from a tertiary care centre","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-30 16:38:18","doi":"10.21203/rs.3.rs-5719155/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"882b9587-0e0d-44c4-94f4-e5afd288097e","owner":[],"postedDate":"December 30th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-02-01T22:08:16+00:00","versionOfRecord":[],"versionCreatedAt":"2024-12-30 16:38:18","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5719155","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5719155","identity":"rs-5719155","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}