Anatomical Features of Posterior Cerebral Arteries and Basilar Artery in 170 Anatolian Fresh Cadavers: Implications for Surgical Planning and Intervention

BACKGROUND

The posterior cerebral arteries (PCAs) are terminal branches of the basilar artery (BA) and are responsible for the primary supply of the occipital lobe. Saccular aneurysm is most commonly seen close to the bifurcation of the BA. Various surgical interventions are performed for aneurysms. Therefore, the anatomy and localization of the BA and PCA are crucial. The aim of this study was to determine the characteristics of these arteries in a large Anatolian population.

METHODS

The study included 170 Anatolian fresh cadavers. The diameters of the BA and PCA were measured. Correlations according to sex and age groups were analyzed. The Q1, Q2, and Q3 angles between the right and left PCA, between the right PCA and BA, and between the left PCA and BA, respectively, were measured. The location of the PCA relative to the sulcus pontocruralis (pontocrural groove) was also evaluated.

RESULTS

The diameter of the artery increased with age and was higher in males than in females. Q1 and Q2 diameters were larger in males, while the Q3 diameter was larger in females. The Q1 angle between the right and left PCAs was found to be higher in age range 40-59 years with a mean of 87.33 ± 17.91 mm. Finally, the bifurcation point of the PCA was most frequently located above the sulcus pontocruralis (pontocrural groove) and least frequently located on the sulcus pontocruralis (pontocrural groove).

CONCLUSIONS

The findings of our study will contribute to the planning of surgical approaches, the development of endovascular devices, the success of invasive procedures, and the reduction of complications.

Basilar apex aneurysm systematic review: Microsurgical versus endovascular treatment

BACKGROUND

Both microsurgical and endovascular techniques continued to be treatment options for basilar apex aneurysms (BAA). We conducted a systematic review to compare both treatment options in terms of both clinical and radiological outcomes.

METHODS

The PRISMA method was used to identify related articles. Data collected from each article and the two treatment approaches were compared in terms of favorable clinical outcome and complete/near complete occlusion rate. Subgroup analysis was done based on the size and the rupture status of BAA.

RESULTS

Fifty-nine (59) and 32 articles reported a measurable clinical and radiological outcome respectively. The weighted average favorable clinical outcome was significantly higher in the endovascular group (86.4% vs 79.6%, P<0.0001), while the weighted average complete/near complete occlusion rate was significantly higher in the surgical group (92.6% vs 83.8%, P<0.0001). In the subgroup analysis, the favorable clinical outcome remained significantly higher in the endovascular group for the ruptured, unruptured and giant/large BAA (P<0.001), but not in the small BAA subgroup (P=0.26). The occlusion rate remained significantly higher in the surgical group for all subgroups (P<0.001).

CONCLUSION

Treatment of BAA remains in a trade-off between favorable clinical outcome and complete or near-complete occlusion depending on the treatment modality selected. Careful selection of cases and judicial discussion between open surgical and endovascular team is warranted for treatment optimization.

Microsurgical Management of Posterior Circulation Aneurysms: A Retrospective Study on Epidemiology, Outcomes, and Surgical Approaches

Posterior circulation aneurysms have been regarded as the most challenging for endovascular coiling and microsurgical occlusion. The role of microsurgical treatment is gradually being overlooked and diminishing in the trend of endovascular treatment. As microsurgical occlusion of posterior circulation aneurysms is decreasing, we present our relevant experience to evaluate treatment options and surgical approaches. A retrospective study was conducted in the Department of Neurosurgery of the First Affiliated Hospital of Soochow University between 2016 and 2021. Patients with posterior circulation aneurysms treated by clipping, bypass, and trapping were enrolled and followed up for at least six months. We included 50 patients carrying 53 posterior circulation aneurysms, 43 of whom had aneurysm ruptures. The posterior cerebral artery and posterior inferior cerebellar artery were the most common aneurysm locations. Direct clipping was performed in 43 patients, while bypass and trapping was performed in six patients. The retrosigmoid, far-lateral, and midline or paramedian suboccipital approaches were performed for those aneurysms in the middle and lower thirds. Aneurysms in the upper third required the lateral supraorbital approach, pterional approach, subtemporal approach, and occipital craniotomy. The lateral supraorbital approach was utilized in seven patients for aneurysms above the posterior clinoid process. Thirty-four patients recovered well with modified Rankin score 0-3 at discharge. No patient experienced aneurysm recurrence during the mean follow-up period of 3.57 years. Microsurgery clipping and bypass should be considered in conjunction with endovascular treatment as a treatment option in posterior circulation aneurysms. The lateral supraorbital approach is a feasible, safe, and simple surgical approach for aneurysms above the posterior clinoid process.

Microsurgical Management of Posterior Circulation Aneurysms: A Retrospective Study on Epidemiology, Outcomes, and Surgical Approaches

Posterior circulation aneurysms have been regarded as the most challenging for endovascular coiling and microsurgical occlusion. The role of microsurgical treatment is gradually being overlooked and diminishing in the trend of endovascular treatment. As microsurgical occlusion of posterior circulation aneurysms is decreasing, we present our relevant experience to evaluate treatment options and surgical approaches. A retrospective study was conducted in the Department of Neurosurgery of the First Affiliated Hospital of Soochow University between 2016 and 2021. Patients with posterior circulation aneurysms treated by clipping, bypass, and trapping were enrolled and followed up for at least six months. We included 50 patients carrying 53 posterior circulation aneurysms, 43 of whom had aneurysm ruptures. The posterior cerebral artery and posterior inferior cerebellar artery were the most common aneurysm locations. Direct clipping was performed in 43 patients, while bypass and trapping was performed in six patients. The retrosigmoid, far-lateral, and midline or paramedian suboccipital approaches were performed for those aneurysms in the middle and lower thirds. Aneurysms in the upper third required the lateral supraorbital approach, pterional approach, subtemporal approach, and occipital craniotomy. The lateral supraorbital approach was utilized in seven patients for aneurysms above the posterior clinoid process. Thirty-four patients recovered well with modified Rankin score 0–3 at discharge. No patient experienced aneurysm recurrence during the mean follow-up period of 3.57 years. Microsurgery clipping and bypass should be considered in conjunction with endovascular treatment as a treatment option in posterior circulation aneurysms. The lateral supraorbital approach is a feasible, safe, and simple surgical approach for aneurysms above the posterior clinoid process.

Influencing Factors for Complication with Aneurysm Rupture of the Fetal Posterior Communicating Artery After Clipping Through the Lateral Supraorbital Approach and Prognosis

Background

To explore the influencing factors for complication with aneurysm rupture of the fetal posterior communicating artery after clipping through the lateral supraorbital (LSO) approach and prognosis.

Methods

A total of 119 patients with posterior communicating artery aneurysm (PCoAA) accompanied by fetal posterior cerebral artery (fPCA), who underwent clipping through the LSO approach from January 2014 to December 2019, were selected. They were aged 50–70 years old, (60.5 ± 13.7) on average. The treatment outcome, incidence of complications and follow-up results were analyzed. Based on the follow-up results, univariate comparative analysis was conducted for the clinical data of patients with good or poor prognosis. The statistically significant factors were incorporated into multivariate Cox regression analysis, and the nomogram prediction model for prognosis was established. The accuracy of the model was assessed using the Hosmer–Lemeshow goodness-of-fit test.

Results

Clipping through the LSO approach was successful in all cases. Perioperative complications occurred in 41 patients. According to the follow-up results, 89 patients had good prognosis, while 30 had poor prognosis. Age of > 65 years old, history of hypertension, high Hunt–Hess grade and high modified Fisher grade were independent risk factors for the poor prognosis of patients with PCoAA accompanied by fPCA after clipping through the LSO approach. The results obtained by the established model were consistent with the actual ones.

Conclusion

Age, history of hypertension, Hunt–Hess grade and modified Fisher grade are independent risk factors for the prognosis of patients with PCoAA accompanied by fPCA after clipping through the LSO approach.

Video Section-Operative Nuances: Step by Step - Single Stage Clipping of Ruptured Middle Cerebral Artery and Unruptured Basilar Top Aneurysm

Background and Introduction

Presence of multiple aneurysms, especially a combination of anterior and posterior circulation aneurysm in the same patient, is rare. Surgical clipping of both the aneurysms in the same sitting, although ideal, may be surgically challenging and requires a good preoperative planning.

Objective

In this video abstract, we present a case of a ruptured middle cerebral artery (MCA) aneurysm with a simultaneous occurrence of an unruptured basilar top aneurysm.

Surgical Technique

A 45-year-old female presented with modified Hunt and Hess grade II subarachnoid hemorrhage (SAH). CT scan showed diffuse SAH with a dense bleed in the left sylvian cistern and mild hydrocephalus. Angiography showed a left MCA aneurysm (34 mm size) with a bleb and also an un-ruptured basilar bifurcation/right posterior cerebral artery aneurysm (20 mm). The patient underwent a left frontotemporal craniotomy, zygomatic osteotomy, and clipping of both aneurysms. No temporary clips were applied. The extended craniotomy allowed the surgeon to reach to the base of the aneurysm.

Results

The patient had an uneventful recovery.

Conclusions

Simultaneous occurrence of both anterior and posterior circulation aneurysms are rare, but maybe tackled surgically with proper planning.

Anterior temporal approach for clipping of ruptured basilar tip aneurysms: Surgical techniques and treatment outcomes

BACKGROUND

Basilar tip (BT) aneurysms are challenging to treat with microsurgical clipping, especially in subarachnoid hemorrhage cases. The anterior temporal approach is one of the surgical approaches for the treatment of aneurysms in this area. The majority of the previous reports on this approach have described unruptured cases. For the ruptured cases assessed in our study, the authors describe the surgical technique, patient characteristics, and surgical outcomes following the use of this technique.

METHODS

Fourteen patients with ruptured BT aneurysms who received aneurysm clipping with an anterior temporal approach between December 2015 and August 2019 were retrospectively evaluated. The surgical techniques are described, an illustrative case is shown.

RESULTS

The average patient age was 62.2 years (range: 46-78) for ten women and four men. Nine patients (64.3%) were classified as having a poor grade (World Federation of Neurosurgical Societies Grades 4 and 5) at the first presentation. All of the cases demonstrated complete aneurysm obliteration. Good outcomes (mRS 0 to 2) at 6 months were achieved in 58.3% of the patients and in 77.8% of the patients who had a good Glasgow Coma Score after resuscitation before surgery. Postoperative transient oculomotor nerve palsy and thalamic infarctions were detected in six patients (42.9%) and two patients (14.3%), respectively.

CONCLUSION

With appropriate case selection, the anterior temporal approach was effective and safe for the clipping of ruptured BT aneurysms.

Endovascular Temporary Balloon Occlusion for Microsurgical Clipping of Posterior Circulation Aneurysms

Based on the relationship between the posterior clinoid process and the basilar artery (BA) apex it may be difficult to obtain proximal control of the BA using temporary clips. Endovascular BA temporary balloon occlusion (TBO) can reduce aneurysm sac pressure, facilitate dissection/clipping, and finally lower the risk of intraoperative rupture. We present our experience with TBO during aneurysm clipping of posterior circulation aneurysms within the setting of a hybrid operating room (hOR). We report one case each of a basilar tip, posterior cerebral artery, and superior cerebellar artery aneurysm that underwent surgical occlusion under TBO within an hOR. Surgical exposure of the BA was achieved with a pterional approach and selective anterior and posterior clinoidectomy. Intraoperative digital subtraction angiography (iDSA) was performed prior, during, and after aneurysm occlusion. Two patients presented with subarachnoid hemorrhage and one patient presented with an unruptured aneurysm. The intraluminal balloon was inserted through the femoral artery and inflated in the BA after craniotomy to allow further dissection of the parent vessel and branches needed for the preparation of the aneurysm neck. No complications during balloon inflation and aneurysm dissection occurred. Intraoperative aneurysm rupture prior to clipping did not occur. The duration of TBO varied between 9 and 11 min. Small neck aneurysm remnants were present in two cases (BA and PCA). Two patients recovered well with a GOS 5 after surgery and one patient died due to complications unrelated to surgery. Intraoperative TBO within the hOR is a feasible and safe procedure with no additional morbidity when using a standardized protocol and setting. No relevant side effects or intraoperative complications were present in this series. In addition, iDSA in an hOR facilitates the evaluation of the surgical result and 3D reconstructions provide documentation of potential aneurysm remnants for future follow-up.

Clip retraction of the tentorium: application of a novel technique for tentorial retraction during supracerebellar transtentorial approaches

Supracerebellar transtentorial (SCTT) approaches have become a popular option for treatment of a variety of pathologies in the medial and basal temporal and occipital lobes and thalamus. Transtentorial approaches provide numerous advantages over transcortical approaches, including obviating the need to traverse eloquent cortex, not requiring parenchymal retraction, and circumventing critical vascular structures. All of these approaches require a tentorial opening, and numerous techniques for retraction of the incised tentorium have been described, including sutures, fixed retractors, and electrocautery. However, all of these techniques have considerable drawbacks and limitations. The authors describe a novel application of clip retraction of the tentorium to the supracerebellar approaches in which an aneurysm clip is used to suspend the tentorial flap, and an illustrative case is provided. Clip retraction of the tentorium is an efficient, straightforward adaptation of an established technique, typically used for subtemporal approaches, that improves visualization and surgical ergonomics with little risk to nearby venous structures. The authors find this technique particularly useful for the contralateral SCTT approaches.

Can sectioning the posterior communicating artery be predicted with computed tomography angiography in the microsurgical clipping of basilar apex aneurysms?

BACKGROUND

Microsurgical clipping is a viable option for managing high-riding basilar apex aneurysms (BAXs) using a transsylvian approach. Cutting the posterior communicating artery (PCoA) at the perforator-free zone provides sufficient exposure of BAX, although it is not always safe. The aim was to qualitatively predict sectioning of the interfering PCoA by using preoperative computed tomographic angiography (CTA).

METHODS

A virtual trajectory from the lesser sphenoid wing to the neck of the aneurysm was simulated on CTA in 19 consecutive patients operated on BAX aneurysms from 2013 to 2018. The angles on CTA resembled the typical view through the extended pterional craniotomy. Next, the ipsilateral PCoA was tracked from the internal carotid to its end at the posterior cerebral artery in the trajectory.

RESULTS

The opticocarotid and carotid-oculomotor window served as the corridors for entering the interpeduncular fossa in 16 patients (84.2%) and in 3 patients (15.8%), respectively. The PCoA was intentionally cut during nine surgeries and preserved in 10 of them. The PCoA was cut more often when positioned toward the cranial base and more medially in the corridor; both the Kernel density analysis and the data points representing the position of the PCoA supported this finding (p < 0.01). The CTA-based position of either ends of the PCoA in the trajectory did not differ between cut and not-cut groups (p = 0.19-0.96). Aneurysm projection, rupture, size, PCoA diameter, length, and other distances on CTA were not related to the sectioning of PCoA (p > 0.05).

CONCLUSIONS

The probability of PCoA sectioning is higher when the PCoA is positioned medially and closer to the cranial base. If the anatomical course of the PCoA is recognized beforehand, it can contraindicate surgery. Preoperative CTA-based planning facilitates the surgery of BAX aneurysms. Therefore, CTA can make microsurgical clipping planning more predictable for the neurosurgeon and safer for the patient.

Supraorbital Keyhole Craniotomy for Basilar Artery Aneurysms: Accounting for the "Cliff" Effect

BACKGROUND

Treatment of basilar artery aneurysms is challenging. While endovascular techniques have dominated, there still remain circumstances where open surgical clipping is required or preferred. Minimally invasive "keyhole" approaches are being used more frequently to provide the durability of surgical clipping with a lower morbidity profile; however, careful patient selection is required. The supraorbital "keyhole" approach has been described for the treatment of basilar artery aneurysms, but careful assessment of the basilar exposure is necessary to ensure proper visualization of the aneurysm and ability to obtain proximal vascular control. Various methods of estimating the basilar artery exposure in this approach have been described, including the anterior skull base line and the posterior clinoid line, but both are unreliable and inaccurate.

OBJECTIVE

To propose a new method, the orbital roof-dorsum line, to simply and accurately predict the basilar artery exposure.

METHODS

CT angiograms for 20 consecutive unique patients were analyzed to obtain the anterior skull base line, posterior clinoid line, and the orbital roof-dorsum line. CT angiograms were then loaded onto a Stealth neuronavigation system (Medtronic, Minneapolis, Minnesota) to obtain "true" visualization lengths. A case illustration is presented.

RESULTS

Pairwise comparison tests demonstrated that both the anterior skull base and the posterior clinoid estimation lines differed significantly from the "true"  value ( P < .0001). Our orbital roof-dorsum estimation provided results that accurately predicted the "true" value ( P = .71).

CONCLUSION

The orbital roof-dorsum line provides a simple and reliable method of estimating basilar artery exposure and should be used whenever considering patients for surgical clipping by this approach.

Ruptured posterior circulation aneurysms: epidemiology, patterns of care, and outcomes from the Swiss SOS national registry

BACKGROUND

The treatment of ruptured posterior circulation aneurysms remains challenging despite progresses in the endovascular and neurosurgical techniques.

OBJECTIVE

To provide epidemiological characterization of subjects presenting with ruptured posterior circulation aneurysms in Switzerland and thereby assessing the treatment patterns and neurological outcomes.

METHODS

This is a retrospective analysis of the Swiss SOS registry for patients with aneurysmal subarachnoid hemorrhage. Patients were divided in 3 groups (upper, lower, and middle third) according to aneurysm location. Clinical, radiological, and treatment-related variables were identified and their impact on the neurological outcome was determined.

RESULTS

From 2009 to 2014, we included 264 patients with ruptured posterior circulation aneurysms. Endovascular occlusion was the most common treatment in all 3 groups (72% in the upper third, 68% in the middle third, and 58.8% in the lower third). Surgical treatment was performed in 11.3%. Favorable outcome (mRS ≤ 3) was found in 56% at discharge and 65.7% at 1 year. No significant difference in the neurological outcome were found among the three groups, in terms of mRS at discharge (p = 0.20) and at 1 year (p = 0.18). High WFNS grade, high Fisher grade at presentation, and rebleeding before aneurysm occlusion (p = 0.001) were all correlated with the risk of unfavorable neurological outcome (or death) at discharge and at 1 year.

CONCLUSIONS

In this study, endovascular occlusion was the principal treatment, with a favorable outcome for two-thirds of patients at discharge and at long term. These results are similar to high volume neurovascular centers worldwide, reflecting the importance of centralized care at specialized neurovascular centers.

Analysis of Surgical Freedom Variation Across the Basilar Artery Bifurcation: Towards a Deeper Insight Into Approach Selection for Basilar Apex Aneurysms

BACKGROUND

The orbitozygomatic approach is generally advocated over the pterional approach for basilar apex aneurysms. However, the impact of the extensions of the pterional approach on the obtained maneuverability over multiple vascular targets (relevant to basilar apex surgery) has not been studied before.

OBJECTIVE

To analyze the patterns of surgical freedom change across the basilar bifurcation between the pterional, orbitopterional, and orbitozygomatic approaches.

METHODS

Surgical freedom was assessed for 3 vascular targets important in basilar apex aneurysm surgery (ipsilateral and contralateral P1-P2 junctions, and basilar apex), and compared between the pterional, orbitopterional, and orbitozygomatic approaches in 10 cadaveric specimens.

RESULTS

Transitioning from the pterional to orbitopterional approach, the surgical freedom increased significantly at all 3 targets (P < .05). However, the gain in surgical freedom declined progressively from the most superficial target (60% for ipsilateral P1-P2 junction) to the deepest target (35% for contralateral P1-P2 junction). Conversely, transitioning from the orbitopterional to the orbitozygomatic approach, the gain in surgical freedom was minimal for the ipsilateral P1-P2 and basilar apex (<4%), but increased dramatically to 19% at the contralateral P1-P2 junction.

CONCLUSION

The orbitopterional approach provides a remarkable increase in surgical maneuverability compared to the pterional approach for the basilar apex target and the relevant adjacent arterial targets. However, compared to the orbitopterional, the orbitozygomatic approach adds little maneuverability except for the deepest target (ie, contralateral P1-P2 junction). Therefore, the orbitozygomatic approach may be most efficacious with larger basilar apex aneurysms limiting the control over of the contralateral P1 PCA.

Adenosine-induced cardiac arrest as an alternative to temporary clipping during intracranial aneurysm surgery

OBJECTIVE

The purpose of this study was to analyze the impact of adenosine-induced cardiac arrest (AiCA) on temporary clipping (TC) and the postoperative cerebral infarction rate among patients undergoing intracranial aneurysm surgery.

METHODS

In this retrospective matched-cohort study, 65 patients who received adenosine for decompression of aneurysms during microsurgical clipping were identified (Group A) and randomly matched with 65 selected patients who underwent clipping but did not receive adenosine during surgery (Group B). The matching criteria included age, Fisher grade, aneurysm size, rupture status, and location of aneurysms. The primary outcomes were TC time and the postoperative infarction rate. The secondary outcome was the incidence of intraoperative aneurysm rupture (IAR).

RESULTS

In Group A, 40 patients underwent clipping with AiCA alone and 25 patients (38%) received AiCA combined with TC, and in Group B, 60 patients (92%) underwent aneurysm clipping under the protection of TC (OR 0.052; 95% CI 0.018–0.147; p < 0.001). Group A required less TC time (2.04 minutes vs 4.46 minutes; p < 0.001). The incidence of postoperative lacunar infarction was equal in both groups (6.2%). There was an insignificant between-group difference in the incidence of IAR (1.5% in Group A vs 6.1% in Group B; OR 0.238; 95% CI 0.026–2.192; p = 0.171).

CONCLUSIONS

AiCA is a useful technique for microneurosurgical treatment of cerebral aneurysms. AiCA can minimize the use of TC and does not increase the risk of IAR and postoperative infarction.

Comparative Analysis of Orbitozygomatic and Subtemporal Approaches to the Basilar Apex: A Cadaveric Study

BACKGROUND

The subtemporal and orbitozygomatic approaches are the most commonly used surgical approaches for the treatment of basilar artery apex (BAX) aneurysms. Relative advantages and disadvantages are generally reported based on surgeons' experience. This study was performed to provide a detailed comparison between the subtemporal and orbitozygomatic approaches based on cadaveric dissection analysis for the treatment of BAX aneurysms.

METHODS

Subtemporal and orbitozygomatic approaches were performed on 5 cadaveric heads (10 sides), and the following variables were assessed and compared between the 2 approaches: 1) number of exposed perforators on P₁-posterior cerebral arteries (PCA); 2) lengths of exposure and clipping for bilateral PCA, superior cerebellar arteries (SCA), and basilar trunk; 3) surgical area of exposure; and 4) surgical freedom at the BAX.

RESULTS

Number of perforators exposed on P₁-PCA was not different between the subtemporal and orbitozygomatic approaches. Exposure and clipping of ipsilateral SCA and PCA were superior using the subtemporal approach, and better for contralateral SCA and PCA using the orbitozygomatic approach, all reaching statistical significance. The orbitozygomatic approach provided greater exposure and clipping length for the proximal basilar trunk. Although the surgical area of exposure was similar between the 2 approaches, the overall surgical freedom was greater in the orbitozygomatic approach.

CONCLUSIONS

The orbitozygomatic approach provides a greater number of surgical corridors to the BAX and is superior regarding multiple surgically relevant anatomic parameters. Importantly, control over the basilar trunk and over the contralateral SCA and PCA (blind spots) is superior with the orbitozygomatic approach.

Pneumatization of the sphenoid sinus, dorsum sellae and posterior clinoid processes in computed tomography

Purpose

Assessment of sphenoid sinus (SS), posterior clinoid process (PCP), and dorsum sellae (DS) pneumatisation is significant when planning surgical approaches both to intra- and extrasellar pathologies. The authors analysed pneumatisation of the SS, with particular attention paid to pneumatisation of the PCP and DS.

Material and methods

The study was based on 100 computed tomography angiography examinations. SS, PCP, and DS pneumatisation grades were assessed using the classification system proposed by Hardy. The analyses were conducted in sagittal planes: midline plane (MP), sagittal posterior clinoid plane right (SPCP-R), and sagittal posterior clinoid plane left (SPCP-L). The occurrence of the highest pneumatisation grade (IVB according to Hardy), which encompasses DS and PCP, prompted the authors to conduct a further analysis in the coronal plane. In this way, seven DS and PCP pneumatisation symmetry types were identified.

Results

In the MP and SPCP-R, the most frequent pneumatisation grade was grade III (41% and 38%, respectively). In the SPCP-L, grade IVA prevailed (41%). Grade IVB was found in 12% of the SPCP-R images, 10% of the SPCP-L images, and in 12% of the MP images. Consistent pneumatisation grades in all analysed planes were found for 64% of cases. This was usually grade III noted in 28% of cases.

Conclusions

SS pneumatisation is characterised by considerable individual variability. There are a number of SS pneumatisation classification systems, but the system proposed by Hardy is the most useful for assessment of DS and PCP pneumatisation. Grade III of SS pneumatisation is the most common. Pneumatisation encompassing DS and PCP was found in 10-12% of cases.

Microsurgical Clipping of Basilar Apex Aneurysms: A Systematic Historical Review of Approaches and their Results

OBJECTIVE

Neck clipping remains a valuable treatment option for basilar apex aneurysms, especially in those with complex morphology, such as incorporation of branching vessels or large size, and young patient age. Several approaches have proved to give effective exposure for various types of lesion morphologies. Our historic literature review from 1976 to the present systematically compares the outcomes and complications of the key surgical approaches in the treatment of basilar apex aneurysms.

METHODS

We searched PubMed for articles with at least 5 patients, data on neurologic outcome, and procedure-associated complications for the following approaches: pterional or orbitozygomatic transsylvian, subtemporal (with or without zygomatic osteotomy), pretemporal (with or without transcavernous extension), and transpetrous. n-Weighted averages for clinical outcome, aneurysm occlusion rates, morbidity, mortality, and aneurysm morphology were compared.

RESULTS

Of 35 articles selected, 2041 patients with 722 ruptured aneurysms underwent microsurgery, including 1131 transsylvian, 241 pretemporal, 375 subtemporal, and 17 transpetrous approaches. Comparing these 4 approaches in n-weighted averages, respectively, we noted good neurologic outcomes (81%, 85%, 81%, and 58%), surgical morbidity (14%, 10%, 34%, and 53%), surgical mortality (4%, 1%, 0, and 1%), and complete occlusion rates (95%, 94%, 86%, and 75%).

CONCLUSIONS

Transsylvian, pretemporal, and subtemporal approaches showed favorable neurologic outcomes at similar rates and were applied for aneurysms located between -1mm and +7mm in relation to the posterior clinoid process. The pretemporal approach was preferably applied to large and giant aneurysms with good outcome; the transsylvian approach was most frequently used for ruptured aneurysms.

Should we still consider clips for basilar apex aneurysms? A critical appraisal of the literature

Background:

Basilar apex aneurysms constitute 5–8% of all intracranial aneurysms, and their treatment remains challenging for both microsurgical and endovascular approaches. The perceived drawback of the microsurgical approach is its invasiveness leading to increased surgical morbidity. However, many high-volume centers have shown excellent clinical results with better occlusion rates compared to endovascular treatment. With endovascular therapy taking a larger role in the management of cerebral aneurysms, the future role of microsurgery for basilar apex aneurysm treatment is unclear.

Methods:

We performed a literature search to review the microsurgical and endovascular outcomes for basilar apex aneurysms.

Results:

Many studies have examined the efficacy of microsurgical and endovascular treatment for intracranial aneurysms, including large randomized trials such as ISAT and BRAT, prospective observational series such as ISUIA, and many single-center retrospective reviews. The recruitment number for posterior circulation aneurysms, specifically for basilar apex aneurysms, was limited in most prospective trials, thus failing to offer clear guidance on basilar apex aneurysm treatment. Recent single-center series report good clinical outcomes between 57–92% for surgical series and 73–96% in endovascular series. The durability of aneurysm occlusion remains superior in surgical cases. The techniques and devices in endovascular treatment have improved treatment aneurysm occlusion rates but more follow-up is needed to confirm long-term durability.

Conclusions:

Both microsurgical and endovascular approaches should be complementing each other to treat basilar apex aneurysms. Although endovascular therapy has taken a larger role in the treatment of basilar apex aneurysms, many indications still exist for the use of microsurgery. Advancements in microsurgical techniques and good case selection will allow for acceptably low morbidity after surgical treatment while maintaining its superior durability.

Comparison between modified lateral supraorbital approach and pterional approach in the surgical treatment of middle cerebral artery aneurysms

Background

The Middle cerebral artery (MCA) aneurysm is a common type of craniocerebral aneurysm that is prone to rupture and high mortality. The classic surgical approaches are the Pterional approach and the Lateral Supraorbital (LSO) approach, but there are shortcomings.

Methods

This study retrospectively analyzed clinical and imaging data from 181 patients with MCA aneurysm clipping in the Department of Neurosurgery, First Affiliated Hospital of Soochow University between 2011 and 2017. Statistical analysis using parametric and nonparametric tests showed that P values below 0.05 were considered statistically significant.

Results

The preoperative GCS score (P = 0.003), Hunt-Hess scale (P < 0.001) and the operating habits of the surgeon (P < 0.001) affected the surgeon to choose a surgical approach. The choice of two surgical methods on the operation time (P < 0.001), skin incision (P < 0.001), complications (P = 0.026), tracheotomy (P = 0.014), prognosis (P = 0.002) were significantly different. Different surgical approaches (P = 0.002), Hunt-Hess scale (P < 0.001), GCS scale (P < 0.001), GCS sorse (P < 0.001), skin incision (P = 0.031) and complications (P < 0.001) are closely related to the prognosis of patients.

Conclusions

Modified LSO approach provides another surgical approach for MCA aneurysm clipping, while avoiding the drawbacks of the LSO approach in the clipping of MCA distal aneurysm.