Several randomized controlled trials are planned or ongoing. In most of these trials, conventional neurosurgical treatment with or without adjunctive endovascular embolization is compared.

Given the encouraging results with a 91% long-term success rate in the series of Link et al., a large scale clinical trial is warranted ¹⁾.

https://clinicaltrials.gov/ct2/show/NCT03307395

A proposed trial aimed to conduct a head-to-head comparison between neurosurgical and endovascular treatment as stand-alone treatments.

The trial is academically driven and funded within existing public healthcare systems and infrastructure. Patients with uni- or bilateral cSDH, presenting with mild-to moderate symptoms, and admitted to neurosurgery on clinical grounds will be offered participation. Subjects are randomized 1:1 between conventional neurosurgical treatment (control) and endovascular embolization of the middle meningeal artery (intervention). Primary endpoint is reoperation due to clinically and/or radiologically significant recurrence within 3 months. Secondary endpoints include safety, technical success rate, neurological disability, and quality of life.

There are mounting retrospective data suggesting eMMA, as sole treatment or as an adjunctive to neurosurgery for cSDH, is safe and effective with a reoperation rate lower than neurosurgical hematoma evacuation alone. If randomized controlled trials confirm these findings, there is a potential for a paradigm shift in the treatment of cSDH where a minimally invasive procedure can replace open surgery in a large and oftentimes old and fragile patient cohort.

Trial registration: ClinicalTrials.gov, ClinicalTrials.gov Identifier NCT05267184 . Registered March 4, 2022 ²⁾.

MEMBRANE is an investigator-initiated, single-center, randomized controlled trial. Male, female, and diverse patients older than 18 years scheduled for surgical evacuation of a first chronic subdural hematoma will be assigned in a 1:1 fashion by block randomization to the chronic subdural hematoma treatment (surgery plus endovascular MMA embolization) or the control group (surgery alone). The primary trial endpoint is chronic subdural hematoma recurrence within 3 months of follow-up after surgery. Secondary endpoints comprise neurological deficits assessed by the modified Rankin Scale (mRS) and recurrence- or intervention-associated complications (see Chronic subdural hematoma surgery complications) see Middle meningeal artery embolization for chronic subdural hematoma complications during 3 months of follow-up. Assuming a risk difference of 20% of rebleeding and surgical revision, a power of 80%, and a drop-out rate of 10%, 154 patients will be enrolled in this trial, employing an adaptive O’Brien-Fleming approach with a planned interim analysis halfway.

The MEMBRANE trial will provide the first clinical experimental evidence on the effectiveness of endovascular embolization of the MMA as an adjunct to surgery to reduce the risk of recurrence after the evacuation of cSDH.

Trial registration: German Clinical Trials Registry (Deutsches Register Klinischer Studien [DRKS]) DRKS00020465. Registered on 18 Nov 2021 ³⁾.

¹⁾

Link TW, Boddu S, Paine SM, Kamel H, Knopman J. Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: A Series of 60 Cases. Neurosurgery. 2019 Dec 1;85(6):801-807. doi: 10.1093/neuros/nyy521. PMID: 30418606.

²⁾

Drake M, Ullberg T, Nittby H, Marklund N, Wassélius J. Swedish trial on embolization of middle meningeal artery versus surgical evacuation in chronic subdural hematoma (SWEMMA)-a national 12-month multi-center randomized controlled superiority trial with parallel group assignment, open treatment allocation and blinded clinical outcome assessment. Trials. 2022 Nov 8;23(1):926. doi: 10.1186/s13063-022-06842-4. PMID: 36348417.

³⁾

Hoenning A, Lemcke J, Rot S, Stengel D, Hoppe B, Zappel K, Schuss P, Mutze S, Goelz L. Middle Meningeal Artery Embolization Minimizes Burdensome Recurrence Rates After Newly Diagnosed Chronic Subdural Hematoma Evacuation (MEMBRANE): study protocol for a randomized controlled trial. Trials. 2022 Aug 22;23(1):703. doi: 10.1186/s13063-022-06506-3. PMID: 35996195.

Anterior communicating artery aneurysm endovascular treatment complications

August 17, 2022

Intraprocedural aneurysm rupture and thrombus formation are serious complications during coiling of ruptured intracranial aneurysms, and they more often occur in patients with anterior communicating artery aneurysms.

It is associated with a high rate of complete angiographic occlusion. However, the procedure-related permanent morbidity and mortality are not negligible for aneurysms in this location ¹⁾.

Delgado Acosta et al. from Hospital Universitario Reina Sofía aimed to report the characteristics of patients suffering intra- or peri-procedural ruptures during embolization of cerebral aneurysms.

Between March 1994 and October 2021, 648 consecutive cerebral aneurysms were treated by the endovascular procedure. Medical records were reviewed retrospectively with emphasis on procedure description, potential risk factors, and clinical outcomes related to intra- or peri-procedural rupture.

Of the 648 patients, 17 (2.6%) suffered an intra- or peri-procedural hemorrhagic event. The most common location was the anterior communicating artery. There was no significant difference between previously ruptured and unruptured aneurysms in the incidence of bleeding. In four patients, bleeding was evident within 24 h after the procedure. The clinical evolution at three months was poor and only four patients presented a positive evolution. There were 11 deaths (64.71%). Balloon remodeling was associated with an increased frequency of ruptures, while stenting was a safer treatment.

Aneurysm rupture during endovascular therapy is unpredictable, and its occurrence can be devastating. The incidence is quite low although the outcome is frequently poor. Early detection and proper management, including prompt occlusion of the aneurysm, are important to achieve a positive outcome. Anterior communicating artery aneurysms and those treated with balloon catheters have a higher incidence of rupture. A small number of ruptures of uncertain origin occur that go unnoticed in digital subtraction angiograms ²⁾.

The immediate and long-term outcomes, complications, recurrences and the need for retreatment were analyzed in a series of 280 consecutive patients with anterior communicating artery aneurysms treated with the endovascular technique. From October 1992 to October 2001 280 patients with 282 anterior communicating artery aneurysms were addressed to our center. For the analysis, the population was divided into two major groups: group 1, comprising 239 (85%) patients with ruptured aneurysms and group 2 comprising of 42 (15%) patients with unruptured aneurysms. In group 1, 185 (77.4%) patients had a good initial pre-treatment Hunt and Hess grade of I-III. Aneurysm size was divided into three categories according to the larger diameter: less than 4 mm, between 4 and 10 mm and larger than 10 mm. The sizes of aneurysms in groups 1 and 2 were identical but a less favorable neck to depth ratio of 0.5 was more frequent in group 2. Endovascular treatment was finally performed in 234 patients in group 1 and 34 patients in group 2. Complete obliteration was more frequently obtained in group 2 unlike a residual neck or opacification of the sac that were more frequently seen in group 1. No peri-treatment complications were recorded in group 2. In group 1 the peri-treatment mortality and overall peri-treatment morbidity were 5.1% and 8.1% respectively. Eight patients (3.4%) in group 1 presented early post treatment rebleeding with a mortality of 88%. The mean time to follow-up was 3.09 years. In group 1, 51 (21.7%) recurrences occurred of which 14 were minor and 37 major. In group 2, eight (23.5%) recurrences occurred, five minor and three major. Two patients (0.8%) presented late rebleeding in group 1. Twenty-seven second endovascular retreatments were performed, 24 (10.2%) in group 1 and three (8.8%) in group 2, seven third endovascular retreatments and two surgical clippings in group 1 only. There was no additional morbidity related to retreatments. Endovascular treatment is an effective method for the treatment of anterior communicating artery aneurysms allowing late rebleeding prevention. Peri-treatment rebleeding warrants caution in anticoagulation management. This is a single center experience and the follow-up period is limited. Patients should be followed-up in the long-term as recurrences may occur and warrant additional treatment ³⁾.

Prolonged anterograde amnesia and disorientation after anterior communicating artery aneurysm coil embolization ⁴⁾

LVIS stent-assisted coiling for ruptured wide-necked ACoA aneurysms was safe and effective, with a relatively low rate of perioperative complications and a high rate of complete occlusion at follow-up ⁵⁾

¹⁾

Fang S, Brinjikji W, Murad MH, Kallmes DF, Cloft HJ, Lanzino G. Endovascular treatment of anterior communicating artery aneurysms: a systematic review and meta-analysis. AJNR Am J Neuroradiol. 2014 May;35(5):943-7. doi: 10.3174/ajnr.A3802. Epub 2013 Nov 28. PMID: 24287090; PMCID: PMC7964525.

²⁾

Delgado Acosta F, Bravo Rey I, Jiménez Gómez E, Saucedo VR, Toledano A, Oteros Fernández R. Intra- or peri-procedural rupture in the endovascular treatment of intracranial aneurysms. Acta Neurol Scand. 2022 Aug 17. doi: 10.1111/ane.13686. Epub ahead of print. PMID: 35975464.

³⁾

Finitsis S, Anxionnat R, Lebedinsky A, Albuquerque PC, Clayton MF, Picard L, Bracard S. Endovascular treatment of ACom intracranial aneurysms. Report on series of 280 patients. Interv Neuroradiol. 2010 Mar;16(1):7-16. doi: 10.1177/159101991001600101. Epub 2010 Mar 25. PMID: 20377974; PMCID: PMC3277962.

⁴⁾

Al-Atrache Z, Friedler B, Shaikh HA, Kavi T. Prolonged anterograde amnesia and disorientation after anterior communicating artery aneurysm coil embolisation. BMJ Case Rep. 2019 Jul 30;12(7). pii: e230543. doi: 10.1136/bcr-2019-230543. PubMed PMID: 31366616.

⁵⁾

Xue G, Liu P, Xu F, Fang Y, Li Q, Hong B, Xu Y, Liu J, Huang Q. Endovascular Treatment of Ruptured Wide-Necked Anterior Communicating Artery Aneurysms Using a Low-Profile Visualized Intraluminal Support (LVIS) Device. Front Neurol. 2021 Jan 28;11:611875. doi: 10.3389/fneur.2020.611875. PMID: 33584512; PMCID: PMC7876256.

Middle cerebral artery M4 segment aneurysm

April 7, 2022

Middle cerebral artery aneurysms, are mainly found in the proximal and bifurcation tracts and only in the 1.1-1.7% of cases they are located in the M4 segment of the middle cerebral artery ¹⁾ ²⁾ ³⁾.

Generally, these aneurysms are secondary to traumatic brain injury and inflammatory or infectious diseases and only rarely they have idiopathic origin ⁴⁾.

At present, only nine cases of ruptured cortical middle cerebral artery aneurysms have been described in literature ⁵⁾ ⁶⁾ ⁷⁾ ⁸⁾ ⁹⁾ ¹⁰⁾.

The patients are all males, except the case of Ricci et al. ¹¹⁾. The average age of the reported patients is 40 years. The size of the aneurysms is between 1 mm and 10 mm and, in most cases, they are saccular intracranial aneurysms or fusiform morphology. In five patients, the aneurysms present infectious etiology. Usually, they occur with ICH, sometimes associated with subarachnoid hemorrhage (SAH).

The endovascular treatment (EVT) has been performed in four cases, while the surgical treatment has been performed in three cases (two of trapping and one of clipping). In one patient, the infectious aneurysm has resolved spontaneously after antibiotic therapy. In all treatments performed, the patients have improved the neurologic symptoms and no residual aneurysms have been observed in the subsequent neuroradiology follow-up ¹²⁾. Although surgery remains the main choice in the M4 aneurysms, because of the extremely distal location of them over the motor/somatosensory cortices, ¹³⁾ Lv et al. ¹⁴⁾ propose the use of the EVT in all types of the M4 aneurysms, especially after the surgery, when it is impossible to locate the small ruptured aneurysm.

The main difficulty of the surgery is the precise surgical localization of the small M4 aneurysms ¹⁵⁾. An inaccurate localization of these vascular lesions may result in larger craniotomies and unnecessary arachnoid and pial dissections with possible resultant permanent neurological injuries ¹⁶⁾.

In cases of aneurysms or arteriovenous malformations located at the sylvian point or at the posterior superior aspect of the insula, especially in dominant hemisphere, to reduce the dissection and open easily sylvian fissure, a logical path would follow the angular artery in the sylvian fissure cutting the arachnoid fibers and retracting only the tissues which are necessary to gain more exposure of the lesion ¹⁷⁾.

A case of a ruptured dissecting pseudoaneurysm in the distal Middle cerebral artery (distal M3/proximal M4) prefrontal division in an healthy young patient (<60 years) successfully treated with a Pipeline Embolization Device. The PED was chosen both as the only vessel sparing option in the young patient as well as for its potential as a vessel sacrifice tool if the pseudoaneurysm was felt to be incompletely treated, which in this case was not necessary-though would have leveraged the thrombogenicity of the device as a therapeutic advantage ¹⁸⁾.

2017

A 53-year-old female was admitted with a sudden severe headache, nausea, vomiting, and a slight left hemiparesis. The computed tomography (CT) scan showed subarachnoid hemorrhage (SAH) in the left sylvian fissure and intracerebral hemorrhage (ICH) in the left posterior parietal area. The CT angiography (CTA) reconstructed with 3D imaging showed a small saccular aneurysm in the M4 segment in proximity of the angular area. A left parieto-temporal craniotomy was performed, the aneurysm was clipped and the ICH evacuated. The motor deficit was progressively recovered. At 3-month follow-up examination, the patient was asymptomatic and feeling well.

Surgery is the best choice for the treatment of ruptured M4 aneurysms with ICH in the opinion of Ricci et al., because it allows to evacuate the hematoma and to exclude the aneurysm from the intracranial circulation. In addition, we suggest both the use of the neuronavigation technique and of the indocyanine green videoangiography (ICGV) for the aneurismal surgery ¹⁹⁾.

2007

A 41-year-old man presented with an infarction manifesting as left-sided weakness and dysarthria. Magnetic resonance angiography revealed a subacute stage infarction in the right MCA territory and complete occlusion of the right ICA. Angiography demonstrated aneurysmal dilatation of the M4 segment of the right MCA. Surgery was performed to prevent hemorrhage from the aneurysm. The aneurysm was proximally clipped guided by Navigation-CT angiography and flow to the distal MCA was restored by superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis ²⁰⁾.

2005

A 20-year-old man with an intracerebral haemorrhage due to a ruptured aneurysm, which arose from a penetrating artery of the distal middle cerebral artery (MCA; M4 segment). Excision of the aneurysm was successfully achieved via a right pterional approach. The follow-up angiogram demonstrated filling of the parent vessel and no residual aneurysm. This report illustrates the angiographical finding of a penetrating artery aneurysm of the distal MCA and summarizes the previous reports to discuss their pathological and clinical characteristics ²¹⁾.

¹⁾ , ⁴⁾ , ⁵⁾ , ²¹⁾

Ahn JY, Han IB, Joo JY. Aneurysm in the penetrating artery of the distal middle cerebral artery presenting as intracerebral haemorrhage. Acta Neurochir (Wien). 2005 Dec;147(12):1287-90; discussion 1290. Epub 2005 Aug 29. PubMed PMID: 16133768.

²⁾ , ⁸⁾ , ¹⁴⁾

Lv N, Zhou Y, Yang P, Li Q, Zhao R, Fang Y, Xu Y, Hong B, Zhao W, Liu J, Huang Q. Endovascular treatment of distal middle cerebral artery aneurysms: Report of eight cases and literature review. Interv Neuroradiol. 2016 Feb;22(1):12-7. doi: 10.1177/1591019915617317. Epub 2015 Dec 3. Review. PubMed PMID: 26637241; PubMed Central PMCID: PMC4757379.

³⁾

Elsharkawy A, Lehečka M, Niemelä M, Billon-Grand R, Lehto H, Kivisaari R, Hernesniemi J. A new, more accurate classification of middle cerebral artery aneurysms: computed tomography angiographic study of 1,009 consecutive cases with 1,309 middle cerebral artery aneurysms. Neurosurgery. 2013 Jul;73(1):94-102; discussion 102. doi: 10.1227/01.neu.0000429842.61213.d5. PubMed PMID: 23615110.

⁶⁾

Horiuchi T, Tanaka Y, Takasawa H, Murata T, Yako T, Hongo K. Ruptured distal middle cerebral artery aneurysm. J Neurosurg. 2004;100:384–8.

⁷⁾

Lee SM, Park HS, Choi JH, Huh JT. Ruptured mycotic aneurysm of the distal middle cerebral artery manifesting as subacute subduralhematoma. J Cerebrovasc Endovasc Neurosurg. 2013;15:235–40.

⁹⁾ , ¹³⁾ , ¹⁵⁾ , ¹⁶⁾

Raza SM, Papadimitriou K, Gandhi D, Radvany M, Olivi A, Huang J. Intra-arterial intraoperative computed tomography angiography guided navigation: a new technique for localization of vascular pathology. Neurosurgery. 2012 Dec;71(2 Suppl Operative):ons240-52; discussion ons252. doi: 10.1227/NEU.0b013e3182647a73. PubMed PMID: 22858682.

¹⁰⁾ , ¹¹⁾ , ¹²⁾ , ¹⁹⁾

Ricci A, Di Vitantonio H, De Paulis D, Del Maestro M, Raysi SD, Murrone D, Luzzi S, Galzio RJ. Cortical aneurysms of the middle cerebral artery: A review of the literature. Surg Neurol Int. 2017 Jun 13;8:117. doi: 10.4103/sni.sni_50_17. eCollection 2017. PubMed PMID: 28680736; PubMed Central PMCID: PMC5482160.

¹⁷⁾

Ausman JI, Diaz FG, Malik GM, Tomecek F. A new microsurgical approach to cerebrovascular lesions of the sylvian point: report of two cases. Surg Neurol. 1990 Jul;34(1):48-51. PubMed PMID: 2360163.

¹⁸⁾

Berwanger RP, Hoover MC, Scott JA, DeNardo AJ, Amuluru K, Payner TD, Kulwin CG, Sahlein DH. The Use of a Pipeline Embolization Device for Treatment of a Ruptured Dissecting Middle Cerebral Artery M3/M4 Aneurysm: Challenges and Technical Considerations. Neurointervention. 2022 Apr 7. doi: 10.5469/neuroint.2022.00045. Epub ahead of print. PMID: 35385900.

²⁰⁾

Lee SH, Bang JS. Distal Middle Cerebral Artery M4 Aneurysm Surgery Using Navigation-CT Angiography. J Korean Neurosurg Soc. 2007 Dec;42(6):478-80. doi: 10.3340/jkns.2007.42.6.478. Epub 2007 Dec 20. PubMed PMID: 19096593; PubMed Central PMCID: PMC2588183.

Unruptured anterior communicating artery aneurysm rupture risk

February 11, 2022

Although the research on the risk factors of anterior communicating artery aneurysm has made great progress, the independent effect of each risk factor on the rupture of AComA aneurysm is controversial among different studies. For this answer Xie et al. will present the results employing the random effects model. Quality assessment of the included studies will be evaluated using the Newcastle–Ottawa Scale. Statistical analyses will be performed using Stata16 (Stata Corporation, College Station, TX, USA) software.The findings of this study will be submitted to peer-reviewed journals for publication. This systematic review will provide evidence to determine the risk factors that affect the rupture of the AComA aneurysm and quantify their independent effects ¹⁾.

Ma et al. found that larger size, greater size ratio, larger flow angle, irregular shape, and smoking of the patient were associated with the rupture of ACoA aneurysms based on univariate analysis. Size ratio (OR = 3.890, P = 0.003), irregular shape (OR = 1.068, P = 0.001), flow angle (OR = 1.054, P = 0.001), and current smoking (OR = 4.435, P = 0.009) were the strongest factors related to ruptured ACoA aneurysms based on multivariate logistic regression analysis. The areas under the curves for the flow angle and size ratio were 0.742 (95% CI 0.646-0.838; P = 0.001) and 0.736 (95% CI 0.621-0.796; P = 0.001), respectively. The strongest risk factors for rupture include size ratio, irregular shape, flow angle, and current smoking. These features should be taken into consideration to aid in the prediction of the rupture risk of ACoA aneurysms ²⁾.

Multiple logistic regression model revealed that A1 dominance [odds ratio (OR) 3.034], an irregular shape (OR 3.358), and an aspect ratio ≥1.19 (AR; OR 3.163) increased the risk of rupture, while cerebral atherosclerosis (OR 0.080), and mean diameters ≥2.48 mm (OR 0.474) were negatively correlated with ACoAA rupture. Incorporating these five factors, the ROC analysis revealed that the threshold value of the multifactors was one, the sensitivity was 88.3%, and the specificity was 66.0%. The scoring model is a simple method that is based on A1 dominance, irregular shape, aspect ratio, cerebral atherosclerosis, and mean diameters from CTA and is of great value in the prediction of the rupture risk of ACoAAs ³⁾.

According to the International Study of Unruptured Intracranial Aneurysms (ISUIA), anterior circulation (AC) aneurysms of <7 mm in diameter have a minimal risk of rupture. It is general experience, however, that anterior communicating artery (AcoA) aneurysms are frequent and mostly rupture at <7 mm. Bijlenga et al. found that AC aneurysms are not a homogenous group. Aneurysms between 4 and 7 mm located in AcoA or distal anterior cerebral artery present similar rupture odds to posterior circulation aneurysms. Intervention should be recommended for this high-risk lesion group ⁴⁾.

For Matsukawa et al. the anterior projection of an ACoA aneurysm may be related to rupturing. The authors would perhaps recommend treatment to patients with unruptured ACoA aneurysms that have an anterior dome projection, a bleb(s), and a size ≥ 5 mm ⁵⁾.

Aneurysms found unruptured in the ACoA show a risk of rupture twice as high as that of other intracranial aneurysms (95% confidence interval, 1.29-3.12). It is the first time this fact has been demonstrated based on the follow-up of unruptured aneurysms.

When deciding whether to operate on UIAs located in the ACoA, surgeons should consider their higher risk of rupture ⁶⁾.

¹⁾

Xie Y, Tian H, Xiang B, Li D, Liu YZ, Xiang H. Risk factors for anterior communicating artery aneurysm rupture: A protocol for systematic review and meta-analysis. Medicine (Baltimore). 2021 Dec 3;100(48):e28088. doi: 10.1097/MD.0000000000028088. PMID: 35049234.

²⁾

Ma X, Yang Y, Liu D, Zhou Y, Jia W. Demographic and morphological characteristics associated with rupture status of anterior communicating artery aneurysms. Neurosurg Rev. 2020 Apr;43(2):589-595. doi: 10.1007/s10143-019-01080-w. Epub 2019 Jan 31. PMID: 30706157.

³⁾

Wang GX, Wang S, Liu LL, Gong MF, Zhang D, Yang CY, Wen L. A Simple Scoring Model for Prediction of Rupture Risk of Anterior Communicating Artery Aneurysms. Front Neurol. 2019 May 31;10:520. doi: 10.3389/fneur.2019.00520. PMID: 31214103; PMCID: PMC6554323.

⁴⁾

Bijlenga P, Ebeling C, Jaegersberg M, Summers P, Rogers A, Waterworth A, Iavindrasana J, Macho J, Pereira VM, Bukovics P, Vivas E, Sturkenboom MC, Wright J, Friedrich CM, Frangi A, Byrne J, Schaller K, Rufenacht D; @neurIST Investigators. Risk of rupture of small anterior communicating artery aneurysms is similar to posterior circulation aneurysms. Stroke. 2013 Nov;44(11):3018-26. doi: 10.1161/STROKEAHA.113.001667. Epub 2013 Jul 30. PMID: 23899912.

⁵⁾

Matsukawa H, Uemura A, Fujii M, Kamo M, Takahashi O, Sumiyoshi S. Morphological and clinical risk factors for the rupture of anterior communicating artery aneurysms. J Neurosurg. 2013 May;118(5):978-83. doi: 10.3171/2012.11.JNS121210. Epub 2012 Dec 14. PMID: 23240701.

⁶⁾

Mira JM, Costa FA, Horta BL, Fabião OM. Risk of rupture in unruptured anterior communicating artery aneurysms: meta-analysis of natural history studies. Surg Neurol. 2006;66 Suppl 3:S12-9; discussion S19. doi: 10.1016/j.surneu.2006.06.025. PMID: 17081844.

Anosmia after anterior communicating artery aneurysm surgery

January 25, 2022

For Bor et al. anosmia occurs after coiling in 1 of every 6 SAH patients, but has a good prognosis in most patients. The cause of anosmia after coiling for ruptured aneurysms remains elusive; severity of the initial hemorrhage or long lasting hydrocephalus may be contributing factors ¹⁾.

In patients with subarachnoid hemorrhage (SAH), anosmia has mainly been reported after surgery for anterior communicating artery aneurysms. Olfactory dysfunction after SAH caused by rupture of the ACoA are very frequent and were present in both treatment groups (aneurysmal clip placement and coil embolization).

Cerebral vasospasm and frontal lobe lesions are related to worse performance on an olfactory test in patients undergoing endovascular coil embolization ²⁾.

Both clip treatment and SAH contribute to the occurrence of anosmia, with different chances of improvement. Olfactory dysfunction occurs in almost all patients on the side of surgery and can occur subclinically after coil deployment ³⁾.

Its occurrence after coiling suggests not only damage to the olfactory nerve by clipping but also that the SAH itself plays a role in its pathogenesis ⁴⁾.

The highest incidence of olfactory dysfunction following a pterional approach and its modifications for an intracranial aneurysm has been reported in cases of anterior communicating artery (ACoA) aneurysms. The radiological characteristics of unruptured ACoA aneurysms affecting the extent of retraction of the frontal lobe and olfactory nerve were investigated as risk factors for postoperative olfactory dysfunction. In cases of unruptured ACoA aneurysm surgery, the height of the aneurysm neck and the estimated extent of brain retraction were both found to be powerful predictors of the occurrence of postoperative olfactory dysfunction. ⁵⁾.

Wongsuriyanan and Sriamornrattanakul published that the interhemispheric approach provided an excellent surgical corridor for clipping anterior communicating artery aneurysms (AcoAAs). However, an important disadvantage of the approach is obtaining proximal control at A1 in the last stage of dissection, especially in anterior or superior projecting AcoAAs and ruptured cases.

Postoperative anosmia was detected in 22.7% ⁶⁾.

For Ito et al. the causes of postoperative anosmia in subfrontal and interhemispheric approach were as follows: sectioning of olfactory tracts intentionally or not, avulsion of olfactory bulbs and probability of ischemic or minor mechanical insults to olfactory tracts. However, these matters rarely occur in posterior interhemispheric approach because of little exposure of olfactory nerves. The mechanisms of postoperative anosmia in posterior interhemispheric approach were considered to be as follows: sinking of frontal lobes due to excessive drainage of cerebrospinal fluid and over-retraction of frontal lobes. The incidence of postoperative anosmia decreased from 27.0% via subfrontal and interhemispheric approach to 5.5% via posterior interhemispheric approach ⁷⁾.

Superior direction of aneurysm appears associated with postoperative olfactory dysfunction. Olfactory protection using gelfoam and fibrin glue could be a simple, safe, and useful method to preserve olfactory function during A-com aneurysm surgery. ⁸⁾.

For Aydin et al. the functions of olfactory nerve could be preserved at a relatively high rate of 85 per cent. This high rate resulted from the microtechnique employed as well as the relatively cautious frontal lobe retraction which was less than 1.5 cm ⁹⁾.

For Fujiwara et al. Unilateral dural incision and unilateral brain retraction without elevation of the frontal lobe from the frontal base are important, because frontal lobe depression and elevation during surgery may injure the olfactory nerve ¹⁰⁾.

Olfactory dysfunction has an important impact on quality of life. Recovery after traumatic anosmia has been recorded up to 5 years after injury. Nevertheless, the authors believe that the damage is permanent when lasting 35 months or longer ¹¹⁾.

The interhemispheric approach (IHA) provides an excellent surgical corridor for clipping anterior communicating artery aneurysms (AcoAAs). However, an important disadvantage of the approach is obtaining proximal control at A1 in the last stage of dissection, especially in anterior or superior projecting AcoAAs and ruptured cases. Wongsuriyanan and Sriamornrattanakul described and evaluated the microsurgical clipping of AcoAAs using the IHA with early A1 exposure.

This was a retrospective descriptive study in patients with AcoAA who received microsurgical clipping through the IHA with early A1 exposure between April 2016 and May 2019. Aneurysm morphology, projection, completeness of clipping, surgical complications, and outcomes were collected from medical records.

Twenty-five patients with AcoAA received microsurgical clipping via the IHA with early A1 exposure. Twenty-three patients (92%) presented with subarachnoid hemorrhage. Intraoperative rupture while dissecting the interhemispheric fissure occurred in 2 cases, for which proximal control via subfrontal route was effectively performed. Of the patients, 100% achieved complete obliteration of their aneurysms. Postoperative anosmia was detected in 22.7%. In ruptured cases, 16 (88.9%) of the good grade patients achieved a good outcome (Glasgow Outcome Scale scores of 4 and 5) at 3 months after the operation.

The IHA with early A1 is safe and effective for clipping AcoAAs. ¹²⁾.

Hendrix et al. assessed the risk for olfactory dysfunction following surgical treatment of unruptured cerebral aneurysm via the supraorbital minicraniotomy. A retrospective review of patients with electively treated cerebral aneurysms who underwent perioperative assessment of olfactory function using a sniffin’ sticks odor identification test between January 2015 and January 2016 was performed. A subgroup of patients without history of subarachnoid hemorrhage, without prior intracranial aneurysm treatment, and confirmed olfactory function underwent supraorbital keyhole craniotomy for aneurysm clipping. Microscopic and endoscopic videos were reviewed for this subgroup. Sixty-four patients who underwent elective aneurysm treatment either via surgical clipping or endovascular aneurysm obliteration were identified. Prior to treatment, 4/64 (6.3%) demonstrated bilateral anosmia. Collectively, 14 patients (21.9%) met subgroup criteria of supraorbital keyhole craniotomy for aneurysm clipping. Here, olfactory performance significantly decreased postoperatively on the side of craniotomy (ipsilateral, P = 0.007), whereas contralateral and bilateral olfactory function remained unaltered (P = 0.301 and P = 0.582, respectively). Consequently, 4/14 patients (28.6%) demonstrated ipsilateral anosmia 3 months after surgery. One patient (1/14, 7.1%) also experienced contralateral anosmia resulting in bilateral anosmia. Intraoperative visualization of the olfactory tract and surgical maneuvers do not facilitate prediction of olfactory outcome. The supraorbital keyhole craniotomy harbors a specific risk for unilateral olfactory deterioration. Lack of perioperative olfactory assessment likely results in underestimation of the risk for olfactory decline. Despite uneventful surgery, prediction of postoperative olfactory function and dysfunction remain challenging ¹³⁾.

A total of 63 patients (aged 41-79 yr, mean 64 yr) with relatively small AcomA aneurysms clipped via the lateral supraorbital approach were retrospectively analyzed among the 105 AcomA aneurysms treated by clipping from 2005 to 2014. Neurological and cognitive functions were examined by several scales, including the modified Rankin Scale (mRS) and Mini-Mental Status Examination. The depressive state was assessed using the Beck Depression Inventory and Hamilton Depression Scale. The state of clipping was assessed 1 yr and then every few years after the operation by 3-dimensional computed tomography angiography.

Complete aneurysm neck clipping was confirmed in 62 aneurysms (98.4%). Perioperative complications occurred in 5 patients (5/63; mild frontalis muscle weakness in 3, anosmia in 1, and meningitis in 1). The mean clinical follow-up period was 5.2 ± 2.1 yr. No patient showed an mRS score more than 2 and all were completely independent in daily life. The depression scores were significantly improved after surgery. The overall mortality was 0% and overall morbidity (mRS score > 2 or Mini-Mental Status Examination score < 24) was 1.6%. All completely clipped aneurysms did not show any recurrence during the mean follow-up period of 4.9 ± 2.1 yr.

Keyhole Lateral supraorbital approach to clip relatively small unruptured AcomA aneurysm promises less invasive and durable treatment ¹⁴⁾.

Cho et al. retrospectively reviewed the medical records of patients who underwent surgical clipping for unruptured aneurysm from 2011-2013 by the same senior attending physician. Since March 2012, olfactory protection using gelfoam and fibrin glue was applied in A-com aneurysm surgery. Therefore we categorized patients in two groups from this time-protected group and unprotected group.

Of the 63 enrolled patients, 16 patients showed postoperative olfactory dysfunction-including 8 anosmia patients (protected group : unprotected group=1 : 7) and 8 hyposmia patients (protected group : unprotected group=2 : 6). Thirty five patients who received olfactory protection during surgery showed a lower rate of anosmia (p=0.037, OR 10.516, 95% CI 1.159-95.449) and olfactory dysfunction (p=0.003, OR 8.693, 95% CI 2.138-35.356). Superior direction of the aneurysm was also associated with a risk of olfactory dysfunction (p=0.015, OR 5.535, 95% CI 1.390-22.039).

Methods: A total of 102 patients who underwent a pterional or superciliary keyhole approach to clip an unruptured ACoA aneurysm from 2006 to 2013 were included in this study. Those patients who complained of permanent olfactory dysfunction after their aneurysm surgery, during a postoperative office visit or a telephone interview, were invited to undergo an olfactory test, the Korean version of the Sniffin’ Sticks test. In addition, the angiographic characteristics of ACoA aneurysms, including the maximum diameter, the projecting direction of the aneurysm, and the height of the neck of the aneurysm, were all recorded based on digital subtraction angiography and sagittal brain images reconstructed using CT angiography. Furthermore, the extent of the brain retraction was estimated based on the height of the ACoA aneurysm neck.

Results: Eleven patients (10.8%) exhibited objective olfactory dysfunction in the Sniffin’ Sticks test, among whom 9 were anosmic and 2 were hyposmic. Univariate and multivariate analyses revealed that the direction of the ACoA aneurysm, ACoA aneurysm neck height, and estimated extent of brain retraction were statistically significant risk factors for postoperative olfactory dysfunction. Based on a receiver operating characteristic (ROC) analysis, an ACoA aneurysm neck height > 9 mm and estimated brain retraction > 12 mm were chosen as the optimal cutoff values for differentiating anosmic/hyposmic from normosmic patients. The values for the area under the ROC curves were 0.939 and 0.961, respectively.

Conclusions: In cases of unruptured ACoA aneurysm surgery, the height of the aneurysm neck and the estimated extent of brain retraction were both found to be powerful predictors of the occurrence of postoperative olfactory dysfunction. ¹⁶⁾.

Matano et al. presented a fibrin-gelatin fixation method that provides reinforcement and moisture to help preserve the olfactory nerve when using the anterior interhemispheric approach and describe the results and outcomes of this technique. We analyze the outcomes with this technique in 45 patients who undergo surgery for aneurysms, brain tumors, or other pathologies via the anterior interhemispheric approach. Anosmia occurred in 4 patients (8.8%); it was transient in 2 (4.4%) and permanent in the remaining 2 (4.4%). Brain tumors clearly attached to the olfactory nerve were resected in the patients with permanent anosmia. We found a significant difference in the presence of anosmia between patients with or without lesions that were attaching the olfactory nerve (p = 0.011). Our results suggested that fibrin-gelatin fixation method can reduce the reported risk of anosmia. However, the possibility of olfactory nerve damage is relatively high when operating on brain tumors attaching olfactory nerve ¹⁷⁾.

Lai et al. presented the operative experiences in a consecutive series of 103 patients with 115 unruptured AcomA aneurysms. Clinical results, operative complications, angiographic outcomes and prognostic factors associated with surgery are presented. Of the 115 aneurysm repairs attempted, 114 were treated by clipping or excision and suture. One aneurysm, less than 2mm, was wrapped. Six patients (5.8%; 95% confidence interval [CI], 2.5-12.4) experienced a new permanent neurological deficit. There was no postoperative mortality. Transient morbidity occurred in 11 patients (10.7%; 95% CI, 5.9-18.3), including transient anosmia (four patients), acute postoperative confusion and memory disturbances (four patients), extradural haematoma requiring surgery (two patients) and cerebrospinal fluid rhinorrhea (one patient). Of the 84 aneurysms (73.0%) that had documented postoperative angiography, 82 (97.6%) had complete obliteration of the aneurysm and two (2.4%) had neck remnants (mean angiographic follow-up 28.0 months; range, 1.6-146.4 months). Retreatment was performed in one patient (1.0%). Logistic regression analysis of risk factors revealed that aneurysm size (p<0.01) was a significant predictor of outcome. There was no incidence of subarachnoid haemorrhage in the 272 person years of follow-up. In the current study, surgical treatment of unruptured AcomA aneurysms resulted in 5.8% morbidity and no mortality. The robustness of aneurysm repair achieved by open microsurgery is an important consideration when considering the option between endovascular and microsurgical treatment for unruptured AcomA aneurysms. ¹⁸⁾.

Nakayama et al. studied the incidence of postoperative infection related to CSF leakage and anosmia in basal interhemispheric approach (BIH). Between April, 1990 to March, 2009, 142 cases of anterior communicating (Acom) aneurysm including both unruptured and ruptured have been treated by clipping surgery using BIH. We retrospectively obtained clinical informations from medical records and video records about infectious complications, CSF leakage of cerebrospinal fluid (CSF), olfactory dysfunction and intraoperative findings of damage to the olfactory nerve. In most cases (139 patients, 97%), frontal sinus were opened at craniotomy. Of all, CSF rinorrhea occurred in 4 cases (2.8%), and meningitis in 6 cases. There was only one patient who sufferd from meningitis due to CSF rinorrhea. All that patients recovered completely without deficit. Anosmia occurred in 6 cases (4.2%), and intraoperative injuries in 4 cases (2.8%). There was only one patient in whom anosmia was consistent with nerve injury. In conclusion, BIH is an appropriate procedure for infection risk control in Acom aneurysm surgery. It is difficult to avoid olfactory dysfunction completely, even if olfactory nerves are preserved in form. ¹⁹⁾.

The horizontal head position was adopted in the unilateral anterior interhemispheric approach to treat an anterior communicating artery (ACoA) aneurysm. The patient was placed in the supine position. The patient’s head was rotated to the right to orient the midline horizontally, and tilted 45 degrees superiorly. After bicoronal skin incision and bifrontal craniotomy, the dura on the right side (downside) was opened. Dissection of the right interhemispheric fissure allowed gravity to retract the right (downside) hemisphere, which fell away from the falx, while the falx supported the upside hemisphere. The present approach was used in three patients with ACoA aneurysm between January 2009 and April 2010. The aneurysms were adequately clipped with this approach. No complication related to the approach occurred. No patients exhibited anosmia after surgery. This approach is useful for ACoA aneurysms. ²⁰⁾.

Beseoglu et al. in 2003 introduced a minimally invasive transorbital keyhole approach. Because this approach requires removal of the orbital rim and orbital roof, there have been concerns regarding perioperative morbidity, long-term morbidity, and cosmetic results. The authors evaluated approach-related morbidity and cosmetic results in their patients to determine the rate of complications and compared this to published reports of similar approaches.

Material: Seventy-one patients (41 female, 30 male) underwent operations using this approach between 2004 and 2008. Immediate approach-related morbidity was recorded after the operation. Late morbidity was determined after 7 months by an independent examiner while cosmetic results were self-rated by the patient using a questionnaire.

Results: Fifty-one (72%) of 71 patients had no postoperative complications and 12 (16.9%) had minor complications, the most common of which was subgaleal CSF collection (7.0%). Other minor complications included facial nerve palsy (2.8%), hyposphagma (2.8%), periorbital swelling due to periorbital hematoma (2.8%), and subdural hematoma (1.4%). Major complications requiring surgical revision occurred in 4 patients (5.6%); these were CSF fistulas in 2 patients, pneumocephalus in 1 patient, and a hematoma in 1 patient. Forty-nine (90.7%) of all 54 examined patients rated the cosmetic results as very good or good. Major long-term morbidity was hyposmia or anosmia (14 patients) followed by hypoesthesia around the scar (9 patients).

The transorbital keyhole approach is a feasible approach with a low-risk profile for postoperative or long-term morbidity and excellent cosmetic outcome ²¹⁾

Although the frequency of smell disorders after the operations of the anterior communicating artery aneurysm depends to a large degree on the used surgical approach, several independent of surgery factors may contribute to the postoperative smell tests outcome. THE AIM OF OUR STUDIES: The evaluation of the sense of smell in patients who underwent the operation of ruptured anterior communicating artery aneurysm using pterional approach.

Material and methods: In the retrospective studies the results of smell test of the group of 21 patients operated for ruptured anterior communicating artery aneurysm and 21 healthy volunteers of control group were compared. The patients suffering from neurodegenerative, metabolic and endocrynological disorders, as well as those with rhinoscopic symptoms of rhinosinusitis and with decreased nasal potency confirmed by anterior rhinomanometry were excluded from the study.

Results: During the operations it was possible to anatomically retain olfactory nerves in all operated patients. Severe smell disorders (severe hyposmia and anosmia) were detected in 1 (4.7%) patient of the control group and in 6 (28.5%) patients of postoperative group. The mean composite olfactory score in Cain test of the postoperative group was 4.53, and in the control group 5.47 points. The difference did not reach statistic significance (Mann-Whitney test, p = 0.068).

Conclusions: Although pterional approach to anterior communicating artery is relatively low traumatic to olfactory tract, the subarachnoid hemorrhage may have an unfavorable effect on postoperative olfactory nerve functioning. Considering the fact, that in spite of thorough examination of the patients, we were not able to exclude from the studied groups all the patients with preoperatively impaired smell, it seems reasonable to perform similar smell test studies in the prospective way ²²⁾.

Bor et al. interviewed all patients who resumed independent living after SAH treated with coiling between 1997 and 2007. We assessed by means of logistic regression analyses whether risk of anosmia was influenced by site of the ruptured aneurysm, neurological condition on admission, amount of extravasated blood, hydrocephalus, and treatment for hydrocephalus.

Of 197 patients, 35 (18%; 95%CI:12 to 23) experienced anosmia. Anosmia had improved in 23 (66%) of them; in 20 the recovery had been complete after a median period of 6 weeks (SD +/-6.5). Intraventricular hemorrhage was a risk factor for anosmia (OR 2.4; 95%CI:1.0 to 5.9). Anterior aneurysm location (OR 1.1; 95%CI:0.5 to 2.3) and high amount of extravasated blood (OR 0.9; 95%CI:0.4 to 2.1) were not related to anosmia.

Anosmia occurs after coiling in 1 of every 6 SAH patients, but has a good prognosis in most patients. The cause of anosmia after coiling for ruptured aneurysms remains elusive; severity of the initial hemorrhage or long lasting hydrocephalus may be contributing factors. ²³⁾.

Martin et al. studied whether and how frequently patients with ACoA aneurysms present with smell identification deficits in 2 treatment groups (endovascular and surgical treatment).

Methods: A prospective study was conducted of patients with SAH caused by ruptured ACoAs and who had a Glasgow Outcome Scale score of 1 or 2, in comparison with a control group matched by age and sex. Olfactory function was assessed using the University of Pennsylvania Smell Identification Test (UPSIT).

Results: A total of 39 patients were enrolled. A marked olfactory impairment was observed in patients with ruptured ACoAs compared with the control group (p < 0.001). Seventeen patients with ruptured ACoAs (44%) compared with 1 patient in the control group (3%) showed a smell identification deficit according to performance on the UPSIT (p < 0.001). Both groups that underwent treatment presented with olfactory impairment. Ten (59%) of 17 patients who underwent aneurysmal clip placement versus 6 (28.5%) of 21 patients who underwent coil embolization scored below the 25th percentile on the UPSIT, and surgical patients also performed worse than endovascular patients (p = 0.048). The authors observed a worse performance on the olfactory test in patients subjected to endovascular coil embolization when cerebral vasospasm (p = 0.037) or frontal cerebral lesions (p = 0.009) were present. This difference was not observed in patients who underwent surgery.

Conclusions: Olfactory disorders after SAH caused by rupture of the ACoA are very frequent and were present in both treatment groups. Cerebral vasospasm and frontal lobe lesions are related to worse performance on an olfactory test in patients undergoing endovascular coil embolization ²⁴⁾.

To discriminate between the effects of aneurysmal rupture and treatment, Moman et al. assessed the occurrence of anosmia after clipping and coiling of unruptured aneurysms as well as after the coiling of ruptured aneurysms.

Methods: The authors interviewed patients in whom an unruptured aneurysm was treated by clipping (32 cases) or endovascular coiling (26 cases) as well as patients with SAH who underwent coil therapy (32 cases). A geographically defined subset of 20 patients per group was invited to undergo olfactory testing.

Results: Nine clip-treated patients (28% [95% CI 14-47%]) in the unruptured group reported having anosmia, and no coil-treated patient in the unruptured group (95% [CI 0-13%]) reported having anosmia; in the SAH group, 7 patients (22% [95% CI 9-40%]) reported having anosmia. Anosmia had improved over time in 3 of the clip-treated patients and in all but 1 of the patients with SAH. Examination revealed olfactory disturbance in 13 (65% [95% CI 41-85%]) of the clip-treated and 8 (42% [95% CI 20-67%]) of the coil-treated patients with unruptured aneurysms, and also in 7 (35% [95% CI 15-59%]) coil-treated patients with SAH. In 20 patients who underwent clip therapy for unruptured aneurysms, 19 (95% [95% CI 75-100%]) had olfactory dysfunction on the side ipsilateral to surgery (anosmia reported by 8 of them).

Conclusions: Both clip treatment and SAH contribute to the occurrence of anosmia, with different chances of improvement. Olfactory dysfunction occurs in almost all patients on the side of surgery and can occur subclinically after coil deployment. ²⁵⁾.

Wermer et al. studied the prevalence, predisposing factors (aneurysm site and type of treatment), impact, and prognosis of anosmia in patients with SAH.

Of the patients with SAH who resumed independent living, we included all patients treated by coiling between 1997 and 2003 and a sample of patients treated by clipping between 1985 and 2001. Patients underwent structured interviews regarding the presence and duration of anosmia. The impact of anosmia was scored using a visual analog scale ranging from 0 (no influence) to 100 (the worst thing that ever happened to them). Risk factors for anosmia were assessed by logistic regression analysis.

Overall, 89 of the 315 interviewed patients (28%; 95% confidence interval [CI], 23-34%) reported anosmia after SAH (mean follow-up period, 7.4 yr), including 10 (15%) of the 67 coiled patients and 79 (32%) of the 248 clipped patients. The median visual analog scale impact score was 53 (range, 0-100). In 20 of the 89 patients (23%; 95% CI, 15-33), the symptoms had improved over time. Risk factors for anosmia were treatment by clipping (odds ratio [OR], 2.7; 95% CI, 1.3-5.7) and anterior communicating artery aneurysms (OR, 2.0; 95% CI, 1.2-3.3).

Anosmia after SAH has a high prevalence, considerable impact, and poor prognosis. Its occurrence after coiling suggests not only damage to the olfactory nerve by clipping but also that the SAH itself plays a role in its pathogenesis. ²⁶⁾

Nozaki et al. described a patient with bilateral persistent primitive olfactory arteries associated with an unruptured saccular aneurysm on the left persistent primitive olfactory artery. Seven reported cases with this anomalous artery including ours are reviewed and classified into two variants. This anomalous artery arises from the terminal portion of the internal carotid artery and courses anteromedially along the ipsilateral olfactory tract and makes a hair-pin curve posterior to the olfactory bulb, becoming the distal anterior cerebral artery (variant 1) or the ethmoidal artery (variant 2). Out of 7 reported cases, 4 cases are associated with saccular aneurysms. The aneurysm in variant 1 is located on the hair-pin curve at which an apparent arterial branch is sometimes absent. Two patients suffer from anosmia. Persistent primitive olfactory artery should be kept in mind because of its high association with intracranial saccular aneurysms and unique clinical presentation. ²⁷⁾.

In as retrospective study, 100 patients with anterior communicating artery aneurysms, for whom the pterional approach was employed, were observed from the point of view of postoperative olfactory nerve function. In the postoperative period only three cases suffered from the impaired sense of smell ipsilateral to the side of surgery. 15 patients objectively showed olfactory nerve distinctions. The functions of olfactory nerve could be preserved at a relatively high rate of 85 per cent. This high rate resulted from the microtechnique employed as well as the relatively cautious frontal lobe retraction which was less than 1.5 cm. ²⁸⁾.

Between 1969 and 1994 we treated 450 patients with ruptured anterior communicating artery aneurysms, of which 434 cases (96.4%) were operated on via the interhemispheric approach (IH), namely, until 1979 mainly, via bifrontal craniotomy, subfrontal and interhemispheric approach (SIH) and, since 1979, via posterior interhemispheric approach (PIH). Postoperative olfactory dysfunction is one of the main disadvantages of IH. The mechanisms and the incidence of this disadvantage were studied in both approaches. The causes of postoperative anosmia in SIH were as follows: sectioning of olfactory tracts intentionally or not, avulsion of olfactory bulbs and probability of ischemic or minor mechanical insults to olfactory tracts. However, these matters rarely occur in PIH because of little exposure of olfactory nerves. The mechanisms of postoperative anosmia in PIH were considered to be as follows: sinking of frontal lobes due to excessive drainage of cerebrospinal fluid and over-retraction of frontal lobes. The incidence of postoperative anosmia decreased from 27.0% via SIH to 5.5% via PIH ²⁹⁾.

The olfactory function could be examined in 101 of 138 patients with anterior communicating artery aneurysms, whom we treated during a recent 6-year period. Among them, 49 patients underwent surgery by the anterior interhemispheric approach and 52 underwent surgery by the basal interhemispheric approach. Fifteen patients (31%) exhibited anosmia after surgery by the anterior interhemispheric approach, whereas only one patient (1.9%) exhibited anosmia after surgery by the basal interhemispheric approach. Unilateral dural incision and unilateral brain retraction without elevation of the frontal lobe from the frontal base are important, because frontal lobe depression and elevation during surgery may injure the olfactory nerve ³⁰⁾.

Yasui et al. reviewed the surgical outcome in 85 patients with ruptured anterior communicating artery (ACoA) aneurysms, who were operated on within 72 hours of onset via a basal interhemispheric (BIH) approach (Group 1, N = 48), or an anterior interhemispheric (AIH) approach (Group 2, N = 37). The age, sex ratio and pre-operative grade (Gr) were similar for both groups. The outcome at the time of discharge was as follows for group 1: excellent or good 88%; fair, 6%; vegetative state, 2% and death 4%. For group 2, it was: excellent or good 78%; fair, 16%; vegetative state, 3%; and death, 3%. A significant correlation between admission grade and outcome was found in both groups. The outcome in group 1 was better than in group 2 for patients with a Glasgow Outcome Scale (GOS) better than fair (p < 0.07). No patient in group 1 had postoperative anosmia, but nine patients in group 2 became anosmic. The total number of complications was also significantly less in group 1. Our overall mortality rate was 4%. In conclusion, the BIH approach was more beneficial for treating acute ACoA aneurysm. ³¹⁾.

In a retrospective study of 25 patients operated on for ruptured intracranial aneurysms via the frontotemporal route, 22 patients suffered postoperatively from anosmia ipsilateral to the side of surgery. This complication most often goes unrecognized by the patient as well as the physician, and attention should be drawn to it because of its widespread occurrence. This investigation demonstrates a high incidence of anosmia (24 (88.9%) of 27 surgical sides) occurring ipsilateral to the frontotemporal approach in aneurysm surgery. Recovery after traumatic anosmia has been recorded up to 5 years after injury. Nevertheless, the authors believe that the damage is permanent when lasting 35 months or longer ³²⁾

¹⁾

Bor AS, Niemansburg SL, Wermer MJ, Rinkel GJ. Anosmia after coiling of ruptured aneurysms: prevalence, prognosis, and risk factors. Stroke. 2009 Jun;40(6):2226-8. doi: 10.1161/STROKEAHA.108.539445. Epub 2009 Apr 16. PMID: 19372449.

²⁾

Martin GE, Junqué C, Juncadella M, Gabarrós A, de Miquel MA, Rubio F. Olfactory dysfunction after subarachnoid hemorrhage caused by ruptured aneurysms of the anterior communicating artery. Clinical article. J Neurosurg. 2009 Nov;111(5):958-62. doi: 10.3171/2008.11.JNS08827. PMID: 19361265.

³⁾

Moman MR, Verweij BH, Buwalda J, Rinkel GJ. Anosmia after endovascular and open surgical treatment of intracranial aneurysms. J Neurosurg. 2009 Mar;110(3):482-6. doi: 10.3171/2008.8.JNS08761. PMID: 19072311.

⁴⁾

Wermer MJ, Donswijk M, Greebe P, Verweij BH, Rinkel GJ. Anosmia after aneurysmal subarachnoid hemorrhage. Neurosurgery. 2007 Nov;61(5):918-22; discussion 922-3. doi: 10.1227/01.neu.0000303187.34308.7b. PMID: 18091268.

⁵⁾ , ¹⁶⁾

Park J, Son W, Goh DH, Kang DH, Lee J, Shin IH. Height of aneurysm neck and estimated extent of brain retraction: powerful predictors of olfactory dysfunction after surgery for unruptured anterior communicating artery aneurysms. J Neurosurg. 2016 Mar;124(3):720-5. doi: 10.3171/2015.1.JNS141766. Epub 2015 Aug 14. PMID: 26274995.

⁶⁾ , ¹²⁾

Wongsuriyanan S, Sriamornrattanakul K. Interhemispheric Approach with Early A1 Exposure for Clipping Anterior Communicating Artery Aneurysms: Operative Techniques and Outcomes. World Neurosurg. 2020 Jun;138:e579-e590. doi: 10.1016/j.wneu.2020.03.005. Epub 2020 Mar 9. PMID: 32165343.

⁷⁾

Ito S, Fujimoto S, Saito K, Tada H, Tanaka T. [Postoperative olfactory dysfunction in interhemispheric approach for ruptured anterior communicating artery aneurysms]. No Shinkei Geka. 1996 Jul;24(7):625-8. Japanese. PMID: 8752875.

⁸⁾ , ¹⁵⁾

Cho H, Jo KI, Yeon JY, Hong SC, Kim JS. Feasibility and Efficacy of Olfactory Protection Using Gelfoam and Fibrin Glue during Anterior Communicating Artery Aneurysm Surgery. J Korean Neurosurg Soc. 2015 Aug;58(2):107-11. doi: 10.3340/jkns.2015.58.2.107. Epub 2015 Aug 28. PMID: 26361525; PMCID: PMC4564741.

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Aydin IH, Kadioğlu HH, Tüzün Y, Kayaoğlu CR, Takçi E, Oztürk M. Postoperative anosmia after anterior communicating artery aneurysms surgery by the pterional approach. Minim Invasive Neurosurg. 1996 Sep;39(3):71-3. doi: 10.1055/s-2008-1052220. PMID: 8892284.

¹⁰⁾ , ³⁰⁾

Fujiwara H, Yasui N, Nathal-Vera E, Suzuki A. Anosmia after anterior communicating artery aneurysm surgery: comparison between the anterior interhemispheric and basal interhemispheric approaches. Neurosurgery. 1996 Feb;38(2):325-8. doi: 10.1097/00006123-199602000-00017. PMID: 8869060.

¹¹⁾ , ³²⁾

Eriksen KD, Bøge-Rasmussen T, Kruse-Larsen C. Anosmia following operation for cerebral aneurysms in the anterior circulation. J Neurosurg. 1990 Jun;72(6):864-5. doi: 10.3171/jns.1990.72.6.0864. PMID: 2338570.

¹³⁾

Hendrix P, Fischer G, Krug J, Linnebach AC, Simgen A, Griessenauer CJ, Burkhardt BW, Oertel J. Olfactory dysfunction in patients undergoing supraorbital keyhole craniotomy for clipping of unruptured aneurysms. Clin Anat. 2020 Mar;33(2):316-323. doi: 10.1002/ca.23529. Epub 2019 Dec 14. PMID: 31769083.

¹⁴⁾

Mori K, Wada K, Otani N, Tomiyama A, Toyooka T, Tomura S, Takeuchi S, Yamamoto T, Nakao Y, Arai H. Long-Term Neurological and Radiological Results of Consecutive 63 Unruptured Anterior Communicating Artery Aneurysms Clipped via Lateral Supraorbital Keyhole Minicraniotomy. Oper Neurosurg (Hagerstown). 2018 Feb 1;14(2):95-103. doi: 10.1093/ons/opx244. PMID: 29228382.

¹⁷⁾

Matano F, Murai Y, Mizunari T, Tateyama K, Kobayashi S, Adachi K, Kamiyama H, Morita A, Teramoto A. Olfactory preservation during anterior interhemispheric approach for anterior skull base lesions: technical note. Neurosurg Rev. 2016 Jan;39(1):63-8; discussion 69. doi: 10.1007/s10143-015-0647-x. Epub 2015 Jul 17. PMID: 26178238.

¹⁸⁾

Lai LT, Gragnaniello C, Morgan MK. Outcomes for a case series of unruptured anterior communicating artery aneurysm surgery. J Clin Neurosci. 2013 Dec;20(12):1688-92. doi: 10.1016/j.jocn.2013.02.015. Epub 2013 Aug 16. PMID: 23958481.

¹⁹⁾

Nakayama H, Ishikawa T, Yamashita S, Fukui I, Mutoh T, Hikichi K, Yoshioka S, Kawai H, Tamakawa N, Moroi J, Suzuki A, Yasui N. [CSF leakage and anosmia in aneurysm clipping of anterior communicating artery by basal interhemispheric approach]. No Shinkei Geka. 2011 Mar;39(3):263-8. Japanese. PMID: 21372335.

²⁰⁾

Hayashi N, Sato H, Akioka N, Kurosaki K, Hori S, Endo S. Unilateral anterior interhemispheric approach for anterior communicating artery aneurysms with horizontal head position–technical note. Neurol Med Chir (Tokyo). 2011;51(2):160-3. doi: 10.2176/nmc.51.160. PMID: 21358165.

²¹⁾

Beseoglu K, Lodes S, Stummer W, Steiger HJ, Hänggi D. The transorbital keyhole approach: early and long-term outcome analysis of approach-related morbidity and cosmetic results. Technical note. J Neurosurg. 2011 Mar;114(3):852-6. doi: 10.3171/2010.9.JNS1095. Epub 2010 Oct 29. PMID: 21029037.

²²⁾

Sieśkiewicz A, Kochanowicz J, Rutkowska J, Rogowski M, Olszewska E. Ocena zaburzeń wechu u chorych po operacji peknietego tetniaka tetnicy łaczacej przedniej mózgu [The evaluation of olfactory dysfunction after the operation of ruptured anterior communicating artery aneurysm]. Pol Merkur Lekarski. 2009 Oct;27(160):302-4. Polish. PMID: 19928658.

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Nozaki K, Taki W, Kawakami O, Hashimoto N. Cerebral aneurysm associated with persistent primitive olfactory artery aneurysm. Acta Neurochir (Wien). 1998;140(4):397-401; discussion 401-2. doi: 10.1007/s007010050114. PMID: 9689332.

²⁸⁾

²⁹⁾

³¹⁾

Yasui N, Nathal E, Fujiwara H, Suzuki A. The basal interhemispheric approach for acute anterior communicating aneurysms. Acta Neurochir (Wien). 1992;118(3-4):91-7. doi: 10.1007/BF01401292. PMID: 1456108.

Carotid Endarterectomy

January 2, 2022

The most common surgical intervention for carotid artery stenosis is carotid endarterectomy (CEA). Many studies on CEA have been reported and suggested medical indications. For symptomatic carotid artery stenosis, generally, CEA may be indicated for patients with more than 50% stenosis and is especially beneficial in men, patients aged 75 years or older, and patients who underwent surgery within 2 weeks of their last symptoms. For asymptomatic carotid artery stenosis. CEA may be indicated for those with more than 60% stenosis, though each guideline has different suggestions in detail. In order to evaluate the indication for CEA in each case, it is important to assess risks for CEA carefully including anatomical factors and comorbidities and to elaborate each strategy for each operation based on preoperative imaging studies including carotid ultrasonography, magnetic resonance imaging, and angiography. In surgery, there are many tips on operative position, procedure, shunt usage, and monitoring to perform a safe and smooth operation. Now that carotid artery stenting has been rapidly developed, a better understanding of CEA is required to treat carotid artery stenosis adequately. ¹⁾.

Carotid artery endarterectomy is widely used on the carotid artery of the neck as a way to reduce the risk of stroke, particularly when the carotid artery is narrowed by more than 70%. A carotid endarterectomy may itself cause a stroke at the time of operation.

Endarterectomy is also used as a supplement to a vein bypass graft to open up distal segments.

Pulmonary hypertension caused by chronic thromboembolic disease (CTEPH) may be amenable to pulmonary thromboendarterectomy of the pulmonary artery. This is a highly specialized procedure.

Carotid artery stenosis (CS) is a major cause of ischemic stroke. Treatment of CS consists of best medical treatment and carotid revascularization (CR), including carotid endarterectomy (CEA) and carotid artery stenting (CAS). Both CR techniques have their own procedural risks. Therefore, selection of the appropriate treatment for patients with CS is relatively complicated. Many studies and guidelines have reported the efficacy of each treatment for both symptomatic and asymptomatic patients. However, the results are still controversial, especially concerning the efficacy and safety of CEA and CAS ²⁾.

Carotid endarterectomy is a surgical procedure to remove the atheromatous plaque material, or blockage, in the lining of an artery constricted by the buildup of soft/hardening deposits. It is carried out by separating the plaque from the arterial wall.

Atherosclerotic stenosis of the internal carotid artery causes 10–15% of all strokes. Carotid endarterectomy lowers the long-term risk of stroke in patients with symptomatic carotid artery stenosis ³⁾ ⁴⁾.

Carotid endarterectomy (CEA) is a common, well-developed surgical procedure.

Technique: Carotid endarterectomy is safe, effective, and durable, but can we make it better? ⁵⁾.

Carotid artery endarterectomy indications.

Identifying patients at high risk for complications after CEA has proven challenging. Typically, the exclusion criteria from studies are cited, but in most cases, these are simply patients that were not included in the study because it was the investigators’ perception that these patients might be “high risk.” Therefore these risk factors are not validated. They are included here for completeness. NASCET and ACAS: age > 80 years, prior ipsilateral CEA, prior contralateral CEA within 4 months, prior neck XRT, tandem lesion larger than target lesion, other conditions that could cause symptoms (atrial fibrillation, prior stroke with persistent major deficit, valvular heart disease), major organ failure, uncontrolled hypertension or diabetes mellitus, and significant coronary artery disease ⁶⁾ ⁷⁾

The SAPPHIRE Trial (Stenting and Angioplasty with Protection in Patients at High-Risk for Endarterectomy): patients with clinically significant cardiac disease (CHF, abnormal stress test, or need for open-heart surgery), severe pulmonary disease, contralateral carotid occlusion, contralateral laryngeal-nerve palsy, previous radical neck surgery or neck XRT, recurrent stenosis after endarterectomy, and age > 80 years ⁸⁾.

The ARCHeR Trial (ACCULINK for Revascularization of Carotids in High-Risk patients) also included patients with tracheostomy, spinal immobility, and dialysis-dependant renal failure ⁹⁾.

Most (but not all) surgeons monitor some parameter of neurologic function during carotid endarterectomy, and will alter technique (e.g. insert a vascular shunt) if there is evidence of hemodynamic intolerance of carotid clamping (only occurs in ≈ 1–4%).

local/regional anesthesia: permits “clinical” monitoring of patient’s neurologic function ¹⁰⁾ ¹¹⁾

Disadvantages:

patient movement during procedure (often exacerbated by sedation and alterations in CBF), lack of cerebral protection from anesthetic and adjunctive agents. The only prospective randomized study found no di erence between local and general anesthesia ¹²⁾. The multicenter, randomized controlled General Anesthesia versus Local Anesthesia (GALA) Trial ¹³⁾ found no significant differences in the prevention of stroke, MI, or death for either anesthetic technique. Subgroup analysis showed trends (not statistically significant) favoring local anesthesia for perioperative death, event-free survival at 1 year, and patients with contralateral occlusion. Local anesthesia was associated with a significant reduction of shunt insertion ¹⁴⁾.

A Cochrane Database Review found no evidence from randomized trials to favor either anesthetic technique ¹⁵⁾

general anesthesia, possibly including barbiturates (thiopental boluses of 125–250 mg until 15– 30 second burst suppression on EEG, followed by small bolus injections or constant infusion to ¹⁶⁾

a) EEG monitoring

b) SSEP monitoring

c) measurement of distal stump pressure after CCA occlusion (unreliable), e.g. using a shunt if stump pressure <25 mm Hg

d) transcranial Doppler

e) near-infrared spectroscopy.

Both general anesthesia and local anesthesia are used in the University Hospital Pilsen for carotid endarterectomy (CEA). The decision as to which anesthetic technique to use during surgery is made individually.

The satisfaction of a group of 205 patients with regard to anesthesia used and their future preferences were evaluated prospectively through a questionnaire. The reasons for dissatisfaction were assessed.

CEA was performed under general anesthesia (GA) in 159 cases (77.6%) and under local anesthesia (LA) in 46 cases (22.4%). In the GA group, 148 patients (93.1%) were satisfied; 30 patients (65.2%) in the LA group were satisfied (p < 0.0001). The reason for dissatisfaction with GA were postoperative nausea and vomiting (7 patients), postoperative psychological alteration (3), and fear of GA (1). The reasons for dissatisfaction with LA were intraoperative pain (9 patients), intraoperative discomfort and stress (5), and intraoperative breathing problems (2). Of the GA group, 154 (96.9%) patients would prefer GA again, and of the LA group, 28 (60.9%) patients would prefer LA if operated on again (p < 0.0001). Overall, 172 patients (83.9%) would prefer GA in the future, and 33 patients (16.1%) would prefer LA.

Overall patient satisfaction with CEA performed under both GA and LA is high. Nevertheless, in the GA group, patient satisfaction and future preference were significantly higher. Both GA and LA have advantages and disadvantages for CEA. An optimal approach is to make use of both anesthetic techniques based on their individual indications and patient preference ¹⁷⁾.

Post-op check

In addition to routine, the following should be checked:

change in neurologic status due to cerebral dysfunction, including:

a) pronator drift(R/O new hemiparesis)

b) signs of dysphasia (especially for left-sided surgery)

c) mimetic muscle symmetry (assesses facial nerve function)

pupil diameter and reaction (R/O stroke, Horner syndrome)
severe H/A (especially unilateral) > may indicate hyperperfusion syndrome
STA pulses (R/O external carotid occlusion)
tongue deviation (R/O hypoglossal nerve injury)
symmetry of lips (R/O weakness of lower lip depressors due to retraction of marginal mandibular branch of the facial nerve against mandible usually resolves in 6–12 wks, must differentiate from central VII palsy due to stroke)
check for hoarseness (R/O recurrent laryngeal nerve injury)
assess for a hematoma in operative site: note any tracheal deviation, dysphagia

A bovine placenta training model for CEA is inexpensive and readily available and closely resembles human carotid arteries. The model can provide a convenient and valuable simulation and practice addition for vascular surgery training ¹⁸⁾.

Neurocognitive performance is used to assess multiple cognitive function, including motor coordination, before and after carotid endarterectomy (CEA).

Carotid artery endarterectomy complications.

Citation analysis on carotid endarterectomy has witnessed a marked shift in the publication trends from studying the outcome and complications to comparing carotid artery stenting with endarterectomy. This analysis is a good introductory article to physicians interested in this topic, as it summarizes the highly impactful articles and enlists the most-cited RCT on CEA ¹⁹⁾.

Carotid artery endarterectomy case series

¹⁾

Hara T, Rai Y. Carotid Endarterectomy. Adv Tech Stand Neurosurg. 2022;44:187-207. doi: 10.1007/978-3-030-87649-4_10. PMID: 35107680.

²⁾

Noiphithak R, Liengudom A. Recent Update on Carotid Endarterectomy versus Carotid Artery Stenting. Cerebrovasc Dis. 2016 Nov 30;43(1-2):68-75. [Epub ahead of print] PubMed PMID: 27898402.

³⁾

North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. N Engl J Med 1991; 325: 445–53.

⁴⁾

European Carotid Surgery Trialists’ Collaborative Group. Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST). Lancet 1998; 351: 1379–87.

⁵⁾

Williamson RW, Spetzler RF. Carotid endarterectomy is safe, effective, and durable, but can we make it better? World Neurosurg. 2016 Jan 2. pii: S1878-8750(15)01794-5. doi: 10.1016/j.wneu.2015.12.087. [Epub ahead of print] PubMed PMID: 26752091.

⁶⁾

Nguyen LL, Conte MS, Reed AB, et al. Carotid endarterectomy: who is the high-risk patient? Semin Vasc Surg. 2004; 17:219–223

⁷⁾

Kang JL, Chung TK, Lancaster RT, et al. Outcomes after carotid endarterectomy: is there a high-risk population? A National Surgical Quality Improvement Program report. J Vasc Surg. 2009; 49:331–8, 339 e1; discussion 338-9

⁸⁾

Yadav JS, Wholey MH, Kuntz RE, et al. Protected carotid-artery stenting versus endarterectomy in high- risk patients. N Engl J Med. 2004; 351:1493–1501

⁹⁾

Gray WA, Hopkins LN, Yadav S, et al. Protected carotid stenting in high-surgical-risk patients: the ARCHeR results. J Vasc Surg. 2006; 44:258–268

¹⁰⁾

Zuccarello M, Yeh H-S, Tew JM. Morbidity and Mortality of Carotid Endarterectomy under Local Anesthesia: A Retrospective Study. Neurosurgery. 1988; 23:445–450

¹¹⁾

Lee KS, Courtland CH, McWhorter JM. Low Morbidity and Mortality of Carotid Endarterectomy Performed with Regional Anesthesia. J Neurosurg. 1988; 69:483–487

¹²⁾

Forssell C, Takolander R, Bergqvist D, et al. Local Versus Gen eral An esth esia in Carotid Surgery. A Prospect ive Randomized Study. Eur J Vasc Surg. 1989; 3:503–509

¹³⁾ , ¹⁴⁾

Lewis SC, Warlow CP, Bodenham AR, Colam B, Rothwell PM, Torgerson D, Dellagrammaticas D, Horrocks M, Liapis C, Banning AP, Gough M, Gough MJ. General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomised controlled trial. Lancet. 2008; 372:2132– 2142

¹⁵⁾

Rerkasem K, Rothwell PM. Local versus general anaesthesia for carotid endarterectomy. Cochrane Database Syst Rev. 2008. DOI: 1 0.1 002/1 465185 8. CD000126.pub3

¹⁶⁾

Spetzler RF, Martin N, Hadley MN, et al. Microsurgical Endarterectomy Under Barbiturate Protection: A Prospective Study. J Neurosurg. 1986; 65:63–73

¹⁷⁾

Mracek J, Kletecka J, Holeckova I, Dostal J, Mrackova J, Mork J, Priban V. Patient Satisfaction with General versus Local Anesthesia during Carotid Endarterectomy. J Neurol Surg A Cent Eur Neurosurg. 2019 Apr 29. doi: 10.1055/s-0039-1688692. [Epub ahead of print] PubMed PMID: 31035296.

¹⁸⁾

Belykh EG, Lei T, Oliveira MM, Almefty RO, Yagmurlu K, Elhadi AM, Sun G, Bichard WD, Spetzler RF, Preul MC, Nakaji P. Carotid Endarterectomy Surgical Simulation Model Using a Bovine Placenta Vessel. Neurosurgery. 2015 Jul 30. [Epub ahead of print] PubMed PMID: 26230044.

¹⁹⁾

Turki E, Almutairi OT, Modhi A, Mohammed B, Alturki AY. A bibliometric analysis on the most-cited publications on carotid endarterectomy throughout history. J Cerebrovasc Endovasc Neurosurg. 2021 Dec 2. doi: 10.7461/jcen.2021.E2021.03.010. Epub ahead of print. PMID: 34852422.

Anterior communicating artery aneurysm endovascular treatment

December 31, 2021

Endovascular treatment has been increasingly performed due to the fact that it is less likely to cause high dysfunction compared to surgery and the treatment has been improved. The International Subarachnoid Aneurysm Trial reported anterior communicating artery aneurysms to comprise 45.4% of cerebral aneurysms on which both endovascular treatment and surgery are suitable. The use of the endovascular treatment for anterior communicating artery aneurysms is expected to increase in the future ¹⁾.

With regard to the endovascular technique, firstly, many Anterior communicating artery aneurysm (AcoA aneurysms) have very small sacs, which makes it difficult to distinguish between the aneurysm neck and the microcatheter selection, leading to a few disadvantages.

The standard coil embolization technique is limited by its inability to occlude wide necked aneurysms. Stent deployment across the aneurysm neck supports the coil mass inside the aneurysmal sac, and furthermore, has an effect on local hemodynamic and biologic changes

In the cases of Choi et al., 17 of 112 aneurysms (15%) had very small sacs, and 15 of these patients (88%) were treated with surgical clipping ²⁾.

The second disadvantage of endovascular treatment for AcoA aneurysms is poor controllability and track-ability due to arterial morphology and the acute angle during the endovascular procedure. Moret et al., ³⁾ reported that the main causes of failure to embolize were loops in the cervical and intracranial vessels despite using the cervical approach when necessary and acute angle changes of the posterior projection of the aneurysm ⁴⁾.

Furthermore, the lumen of the AcoA is relatively small, and remodeling neck techniques using balloons or stents is particularly difficult when treating wide neck or complex aneurysms Safe and complete endovascular occlusion of these aneurysms usually requires the assistance of combined approaches using balloons and stents in an individually tailored strategy ⁵⁾.

The treatment modality of AcoA aneurysms is affected more by anatomic factors than other aneurysms. However, optimal treatment for AcoA aneurysms cannot be determined by any one anatomic characteristic; rather, all of the morphological features and clinical factors must be considered.

Many papers have emphasized the need for a collaborative approach to treatment strategies and have shown varying tendencies toward coiling or clipping ⁶⁾

The decision-making process during recent years has become increasingly more based on collaboration. All patient cases are discussed by a team including at least one endovascular specialist, one neurosurgeon, and one neurologist. Those presenting acutely are always routinely reviewed by both a surgeon and an endovascular radiologist.

In the study of Choi et al., correlated 5 clinical factors and 5 anatomical factors related to determining treatment modality with clinical and anatomical outcomes. Of the 5 clinical factors, age was the important factor in both uni and multivariate analysis. Older patients (age, >65 years) had significantly higher odds of being treated with coil embolization vs. clipping (adjusted OR, 3.78; 95% CI, 1.39-10.3; p=0.0093). The anatomical factors that affected initial treatment modality decision included aneurysm size (small or large vs. medium), neck size (<4 vs. ≥4) dome-to-neck ratio (<2 vs. ≥2), vessel incorporation, multiple lobulation, and morphologic score. Among these 5 anatomical factors, small or large size, dome-to-neck ratio <2, vessel incorporation, and morphologic score ≥2 were statistically significant in univariate analysis. In multivariate analysis, only morphologic score was statistically significant.

Patients with more than 2 unfavorable factors were treated with surgical clipping 4.34 times more often than with coil embolization. Furthermore, higher scoring patients had a higher tendency to be treated with surgical clipping

Balloon remodeling should be considered for broad-based complex ACoA aneurysms. This technique provides a high rate of aneurysm occlusion with an acceptable complication profile, and avoids the need for dual antiplatelet therapy. The balloon trajectory will depend on aneurysm morphology and bilateral access may be useful in selected cases ⁷⁾.

Prolonged anterograde amnesia and disorientation after anterior communicating artery aneurysm coil embolization ⁸⁾

¹⁾

Takeuchi M, Uyama A, Matsumoto T, Tsuto K. Endovascular Treatment for Anterior Communicating Artery Aneurysms. Adv Tech Stand Neurosurg. 2022;44:239-249. doi: 10.1007/978-3-030-87649-4_13. PMID: 35107683.

²⁾

Choi JH, Kang MJ, Huh JT. Influence of clinical and anatomic features on treatment decisions for anterior communicating artery aneurysms. J Korean Neurosurg Soc. 2011 Aug;50(2):81-8. doi: 10.3340/jkns.2011.50.2.81. Epub 2011 Aug 31. PubMed PMID: 22053224; PubMed Central PMCID: PMC3206283.

³⁾

Moret J, Pierot L, Boulin A, Castaings L, Rey A. Endovascular treatment of anterior communicating artery aneurysms using Guglielmi detachable coils. Neuroradiology. 1996;38:800–805.

⁴⁾

Proust F, Debono B, Hannequin D, Gerardin E, Clavier E, Langlois O, et al. Treatment of anterior communicating artery aneurysms : complementary aspects of microsurgical and endovascular procedures. J Neurosurg. 2003;99:3–14.

⁵⁾

Cohen JE, Melamed I, Itshayek E. X-microstenting and transmesh coiling in the management of wide-necked tent-like anterior communicating artery aneurysms. J Clin Neurosci. 2013 Nov 28. pii: S0967-5868(13)00496-7. doi: 10.1016/j.jocn.2013.09.003. [Epub ahead of print] PubMed PMID: 24291480.

⁶⁾

Cowan JA, Jr, Ziewacz J, Dimick JB, Upchurch GR, Jr, Thompson BG. Use of endovascular coil embolization and surgical clip occlusion for cerebral artery aneurysms. J Neurosurg. 2007;107:530–535.

⁷⁾

Moon K, Albuquerque FC, Ducruet AF, Crowley RW, McDougall CG. Balloon remodeling of complex anterior communicating artery aneurysms: technical considerations and complications. J Neurointerv Surg. 2014 Apr 28. doi: 10.1136/neurintsurg-2014-011147. [Epub ahead of print] PubMed PMID: 24778138.

⁸⁾

Double origin of the posterior inferior cerebellar artery

July 3, 2021

Double origin of the posterior inferior cerebellar artery

The posterior inferior cerebellar artery (PICA) frequently arises from the fenestrated segment of the intracranial vertebral artery (VA), and this common variation can be misinterpreted as or confused with a PICA of double origin. Rarely, a PICA of true double origin occurs when two branches of the PICA arise separately from the intracranial VA and fuse to form an arterial ring.

Uchino et al. discovered this rare variation incidentally while interpreting images of magnetic resonance angiography. This is the first report of MR angiographic findings of this rare variation ¹⁾.

For Lesley et al. double origin of the PICA is seen in 4.1% of patients with intracranial aneurysms and on 1.45% of catheter angiograms. The double origin of the PICA has an increased association with intracranial aneurysmal disease and may represent a risk factor for subsequent development of an intracranial aneurysm ²⁾.

Posterior fossa arteriovenous malformations (AVMs), especially cerebellar arteriovenous malformations, are also not common. Consequently, the association of a Double origin of the posterior inferior cerebellar artery (DOPICA) with a cerebellar AVM is even rare.

Rodriguez-Calienes et al. presented a rare case of a pediatric cerebellar AVM supplied by a branch of a DOPICA which was treated endovascularly with NBCA. Total obliteration was achieved in the immediate controls and at 1-year follow-up.

Navigation through tortuous and long branches from a DOPICA is technically feasible. Although NBCA cure rates are relatively low, when the microcatheter can no longer navigate through the feeding artery, a correct dilution of NBCA with lipiodol can provide adequate penetration of this embolic agent, to obliterate the AVM nidus completely ³⁾.

A cadaveric specimen was prepared for dissection. A far lateral craniotomy was performed on the right side. While exploring the right cerebellomedullary cistern, two separate origins of PICA were found from the vertebral artery (VA) as the caudal and rostral trunks that joined to form the distal PICA trunk at the tonsillomedullary segment. Microscopic and endoscopic illustrations are provided.

To the best of the authors’ knowledge, this is the first anatomic report on the DOPICA. Cadaveric illustration of this variant helps with understanding its anatomical relationship with adjacent neurovascular structures of the cerebellomedullary cistern including the perforating arteries and the lower cranial nerves ⁴⁾.

Cho et al. demonstrated the first case of double origin of the posterior inferior cerebellar artery (PICA) with juxta-proximal fenestration of the caudal component, which was misunderstood as triple origin, combined with an unruptured middle cerebral artery aneurysm. The caudal component of the PICA originated from the atlanto-occipital portion and it was fenestrated shortly after origin. The cranial component originated from the intracranial vertebral artery and converged with the superior branch of the caudal component, and then met the inferior branch of the caudal component distally ⁵⁾.

Two cases of anatomical variation of the PICA that they have called its double origin, one of which gave rise to an aneurysm. The first patient was a 36-year-old man who presented with a subarachnoid hemorrhage related to the rupture of a PICA aneurysm. The aneurysm was treated by the endovascular route. Selective and super selective studies showed that the PICA origin was low on the fourth segment of the vertebral artery (VA). The aneurysm was located on an anastomosis between the PICA and a small upper arterial branch originating from the VA. Embolization was performed through the small branch with no problem, but a lateral medullary infarct followed, probably due to occlusion of the perforating vessels. The same anatomical variation was incidentally discovered in the second patient. To the authors’ knowledge, neither this anatomical variation of the PICA nor the aneurysm’s topography has been previously described angiographically. This highlights the role of angiography in pretreatment evaluation of aneurysms especially when perforating vessels or small accessory branches that are poorly visualized on angiographic studies are concerned, as in the territory of the PICA. Anatomy is sometimes unpredictable, and the surgeon must be very careful when confronted with these variations because they are potentially dangerous for endovascular treatment ⁶⁾.

¹⁾

Uchino A, Saito N, Ishihara S. Double Origin of the Posterior Inferior Cerebellar Artery Diagnosed by MR Angiography: A Report of Two Cases. Neuroradiol J. 2015 Apr;28(2):187-9. doi: 10.1177/1971400915576659. Epub 2015 Apr 13. PMID: 25923681; PMCID: PMC4757150.

²⁾

Lesley WS, Rajab MH, Case RS. Double origin of the posterior inferior cerebellar artery: association with intracranial aneurysm on catheter angiography. AJR Am J Roentgenol. 2007 Oct;189(4):893-7. doi: 10.2214/AJR.07.2453. PMID: 17885063.

³⁾

Rodriguez-Calienes A, Saal-Zapata G, De la Cruz J. Endovascular Treatment of an Arteriovenous Malformation Associated with a Double Origin of the Posterior Inferior Cerebellar Artery. Pediatr Neurosurg. 2021 Jul 8:1-5. doi: 10.1159/000517248. Epub ahead of print. PMID: 34237747.

⁴⁾

Meybodi AT, Moreira LB, Zhao X, Lawton MT, Preul MC. Double Origin of the Posterior Inferior Cerebellar Artery: Anatomic Case Report. World Neurosurg. 2019 Jan 3:S1878-8750(18)32950-4. doi: 10.1016/j.wneu.2018.12.127. Epub ahead of print. PMID: 30611945.

⁵⁾

Cho YD, Han MH, Lee JY. Double origin of the posterior inferior cerebellar artery with juxta-proximal fenestration of caudal component. Surg Radiol Anat. 2011 Apr;33(3):271-3. doi: 10.1007/s00276-010-0747-9. Epub 2010 Nov 24. PMID: 21107570.

⁶⁾

Pasco A, Thouveny F, Papon X, Tanguy JY, Mercier P, Caron-Poitreau C, Herbreteau D. Ruptured aneurysm on a double origin of the posterior inferior cerebellar artery: a pathological entity in an anatomical variation. Report of two cases and review of the literature. J Neurosurg. 2002 Jan;96(1):127-31. doi: 10.3171/jns.2002.96.1.0127. PMID: 11794593.

Malignant middle cerebral artery territory infarction

June 27, 2021

The malignant middle cerebral artery territory infarction is a distinct syndrome that occurs in up to 10% of stroke patients, ¹⁾ ²⁾ which carries a mortality of up to 80% (mostly due to severe postischemic cerebral edema → increased ICP → herniation ³⁾

Patients usually present with findings of severe hemispheric stroke (hemiplegia, forced eye and head deviation) often with CT findings of major infarct within the first 12 hours. Most develop drowsiness shortly after admission. There is progressive deterioration during the first 2 days, and subsequent transtentorial herniation usually within 2–4 days of stroke. Fatalities are often associated with: severe drowsiness, dense hemiplegia, age > 45–50 yrs, ⁴⁾ early parenchymal hypodensity involving > 50% of the MCA distribution on CT scan,23 midline shift > 8–10 mm, early sulci effacement, and hyperdense artery sign (p. 1354) ⁵⁾ in MCA. Neurosurgeons may become involved in caring for these patients because aggressive therapies in these patients may reduce morbidity and mortality. Options include:

conventional measures to control ICP (with or without ICP monitor): mortality is still high in this group and elevated ICP is not a common cause of initial neurologic deterioration in large hemispheric stroke

2. hemicraniectomy (decompressive craniectomy):

✖ to date, the following treatments have not improved outcome: agents to lyse clot, hyperventilation, mannitol, or barbiturate coma.

In patients with severe middle cerebral artery (MCA), intracranial atherosclerotic disease (ICAD), the mechanism of stroke is multifactorial, but hemodynamic insufficiency plays a significant role. This finding is important in selecting a subgroup of patients who may benefit from revascularization ⁶⁾.

see Malignant middle cerebral artery syndrome.

Malignant middle cerebral artery territory infarction diagnosis.

Malignant middle cerebral artery territory infarction treatment.

Malignant middle cerebral artery territory infarction outcome.

A case of a child with serological evidence of SARS-CoV-2 infection whose onset was a massive right cerebral artery ischemia that led to a malignant cerebral infarction. The patient underwent a life-saving decompressive hemicraniectomy, with good functional recovery, except for residual hemiplegia. During rehabilitation, the patient also developed a lower extremity peripheral nerve neuropathy, likely related to a long-Covid syndrome ⁷⁾.

A 39-year-old woman in the 24th week of pregnancy who suffered a right malignant MCA infarction that eventually required DC. The patient delivered a healthy baby and underwent a second surgery for cranioplasty 7 months later. ⁸⁾.

¹⁾

Moulin DE, Lo R, Chiang J, et al. Prognosis in Middle Cerebral Artery Occlusion. Stroke. 1985;16:282–284

²⁾ , ³⁾

Hacke W, Schwab S, Horn M, et al. Malignant Middle Cerebral Artery Territory Infarction: Clinical Course and Prognostic Signs. Arch Neurol. 1996; 53:309–315

⁴⁾ , ⁵⁾

Wijdicks EFM, Diringer MN. Middle Cerebral Artery Territory Infarction and Early Brain Swelling: Progression and Effect of Age on Outcome. Mayo Clin Proc. 1998; 73:829–836

⁶⁾

Dubow JS, Salamon E, Greenberg E, Patsalides A. Mechanism of Acute Ischemic Stroke in Patients with Severe Middle Cerebral Artery Atherosclerotic Disease. J Stroke Cerebrovasc Dis. 2014 Jan 11. pii: S1052-3057(13)00425-4. doi: 10.1016/j.jstrokecerebrovasdis.2013.10.015. [Epub ahead of print] PubMed PMID: 24424333.

⁷⁾

Scala MR, Spennato P, Cicala D, Piccolo V, Varone A, Cinalli G. Malignant cerebral infarction associated with COVID-19 in a child. Childs Nerv Syst. 2021 Jun 26. doi: 10.1007/s00381-021-05273-x. Epub ahead of print. PMID: 34175976.

⁸⁾

Fernández García A, Jiménez Zapata HD, de Lera Alfonso MC, Sánchez Fernández C, Jiménez Arribas P, Rodríguez Arias CA. Decompressive Craniectomy in Pregnant Women. J Neurol Surg A Cent Eur Neurosurg. 2021 Jun 2. doi: 10.1055/s-0041-1726108. Epub ahead of print. PMID: 34077979.

Anterior communicating artery aneurysm

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Risk Factors

Clinical features

Diagnosis

Treatment

Outcome

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Case series

Case reports

Latest PubMed Anterior communicating artery aneurysm related articles

Middle meningeal artery embolization for chronic subdural hematoma trials

Anterior communicating artery aneurysm endovascular treatment complications

terior communicating artery aneurysm endovascular treatment complications

Middle cerebral artery M4 segment aneurysm

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Unruptured anterior communicating artery aneurysm rupture risk

Anosmia after anterior communicating artery aneurysm surgery

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Carotid Endarterectomy

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Pre-op risk factors for CEA

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Post-op check

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Anterior communicating artery aneurysm endovascular treatment

Balloon remodeling

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Double origin of the posterior inferior cerebellar artery

Malignant middle cerebral artery territory infarction

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