Aneurysms of the ophthalmic segment. A clinical and anatomical analysis

Comparative analysis of optical coherence tomography angiography findings before and after flow-diverting stent treatment covering the ophthalmic artery origin in the management of paraclinoid aneurysms

PURPOSE

Flow-diverter stents (FDSs) are being increasingly used for endovascular treatment of paraclinoid aneurysms. However, their impact on ophthalmic artery (OA) flow and retinal microvasculature remains unclear. Using optical coherence tomography angiography (OCTA), we evaluated the microvascular changes after FDS placement on the OA.

METHODS

This retrospective study included 38 patients with paraclinoid aneurysms who had an FDS placed on the OA origin. OCTA imaging was performed preoperatively, on postoperative day 1, and at the 6th month. The superficial and deep capillary plexus (SCP, DCP) densities in the treated and untreated fellow eyes were determined and compared with a control group of 31 healthy individuals who underwent single-session OCTA. OA status and stent-related changes were assessed at the 6th month follow-up with digital subtraction angiography (DSA).

RESULTS

A significant reduction in SCP and DCP densities was observed in the stent-treated eyes over time, particularly in the central, superior, temporal, and inferior regions (p < 0.05), while untreated fellow eyes and controls showed no significant changes.

CONCLUSION

FDS placement covering the OA orifice leads to measurable retinal microvascular changes that are detectable by OCTA, demonstrating the value of the latter as a useful non-invasive tool for this purpose.

The 'Slingshot' technique: balloon-guide assisted tracking of distal systems past tortuosity and ledges in thrombectomy

BACKGROUND

We describe and analyze a novel technique by which inflation of a proximal balloon guide catheter (BGC) permits tracking of distal catheter systems past vessel tortuosity and ledges like the ophthalmic segment of the internal carotid artery (ICA). Inflation of the BGC counteracts slippage when deployed, and careful advancement of the system builds up energy that is translated forward, allowing users to cross segments otherwise inaccessible by endovascular techniques.

METHODS

A retrospective review of our institutional neurovascular database was conducted, and we identified nine patients for whom the novel 'Slingshot' technique was used for mechanical thrombectomy. Patient characteristics, outcomes, and procedural steps were collected and analyzed with regards to safety and efficacy of the technique.

RESULTS

The Slingshot technique was successful in all nine cases to navigate the distal system to the target location. For all cases, conventional tracking of the catheter failed, and the Slingshot technique was used as a rescue. No intraoperative complications such as vessel dissection or perforation were observed. First pass recanalization was achieved in seven (78%) cases with successful reperfusion (thrombolysis in cerebral infarction ((TICI) ≥2B) in all cases. Patient outcome was favorable with National Institutes of Health Stroke Scale (NIHSS) score improvement from a median of 16 to 3 postoperatively.

DISCUSSION

For neurovascular procedures in which advancement of an intermediate catheter or other equipment is limited by ledges or tortuosity, the Slingshot technique is a safe and effective way to reach the intended target position and does not require additional catheters or devices.

Superior hypophyseal artery aneurysm: microsurgical vs. endovascular treatment

This study aimed to provide an updated evidence of superior hypophyseal artery (SHA) aneurysms management, including their clinical implications, predictive factors for rupture, therapeutic approaches, and post-treatment outcomes. This systematic review and meta-analysis, following PRISMA guidelines, assessed the literature on superior hypophyseal artery aneurysms. Studies were selected based on predefined criteria, focusing on coiling and clipping interventions. Data were extracted and analyzed using SPSS and Cochrane RevMan, with assessments of heterogeneity, sensitivity, and publication bias. Study quality was evaluated using the Newcastle-Ottawa Scale and RoB2. A total of 20 studies involving 316 patients were included. The clipping group had a mean age of 53.8 years, while the coiling group had 50.3 years. Most aneurysms were smaller than 7 mm. Aneurysm remnants occurred in 1.1% after clipping and 2.8% after coiling. Clipping was associated with lower recurrence rates (0% vs. 9.3%) and fewer visual disturbances and vasospasms. Mortality was equal (1%) for both groups. The coiling group had better outcomes on the modified Rankin Scale (94% vs. 73% for clipping). Meta-analysis confirmed that clipping had better recurrence and functional outcomes, with no significant differences in aneurysm size or mortality. Surgical clipping is a viable treatment for SHA aneurysms but carries risks, while coil embolization offers a safer, effective alternative. Early intervention, especially for larger aneurysms (> 7 mm), is crucial to prevent rupture. Future research should focus on personalized treatment strategies, as this study's small sample size and study limitations warrant further investigation.

Improvement in cranial nerve palsies following treatment of intracranial aneurysms with flow diverters: Institutional outcomes, systematic review and study-level meta-analysis

BACKGROUND

Cranial nerve (CN) palsies are rare presenting symptoms of intracranial aneurysms. Our objectives were to report our institutional outcomes and study-level meta-analysis summarizing rates of improvement and identifying factors associated with recovery from CN symptoms after flow diversion.

METHODS

We conducted a retrospective review of our institutional database for patients with intracranial aneurysms presenting with CN palsies who underwent treatment with flow diversion between 2015 and 2023. Systematic review of the literature was performed using Medline, EMBASE, Cochrane, as well as manual citation searches. Random effects meta-analysis was used.

RESULTS

Thirteen of 136 studies were included in the meta-analysis and were combined with our institutional data. The pooled rate of improvement in any CN palsies following flow diversion was 71 % (95 %CI, 60 %-82 %, n=322). Patients presenting with CN II deficits were less likely to improve following treatment compared to other CN deficits (pooled OR [pOR] 0.32, 95 %CI, 0.16-0.63, n=224). The pooled rate of clinical improvement was 53 % in CNII deficits (95 %CI, 42 %-65 %, n=80) and 80 % in other CN deficits (95 %CI, 71 %-88 %, n=106). An increased rate of improvement was associated with acute intervention (pOR 9.12, 95 % CI, 2.26-36.73, n = 71) and radiographic aneurysm occlusion (pOR 5.29, 95 %CI, 1.66-16.90, n=118).

CONCLUSIONS

Flow diversion improves CN palsy outcomes in patients with symptomatic intracranial aneurysms. The lower rate of improvement in visual acuity compared to other CN deficits may point to a different mechanism of injury or potential recoverability in these patients.

Cranial nerve palsies and intracranial aneurysms: A narrative review of patterns and outcomes

Background

Cranial nerve palsy (CNP) in patients with intracranial aneurysms (IAs) can impose significant burdens on a patient's quality of life. The literature has a paucity of reviews addressing patterns of overall reported cranial nerve (CN) involvement and outcomes in patients with IA.

Methods

The literature systematically reviewed CNP at presentation in the setting of IA using PubMed, Web-of-Science, and Scopus according to the PRISMA guidelines.

Results

Fifty-two studies reported a total of 513 patients with IA and 630 CNPs observed at presentation: oculomotor (58.25%), abducent (15.87%), optic (12.06%), trochlear (8.7%), and trigeminal (1.9%). Most common aneurysms are located in a posterior communicating artery (46%) and cavernous internal carotid artery (29.2%). Trends of CNP based on the rupture status of IAs showed that 80% were associated with unruptured IAs and 20% with ruptured IAs. Post-treatment of IA, 55% of patients had complete resolution of CNP, with most (89%; n = 134) resolving within the first 6 months. Stratified by CNP type: Complete resolution rate is 100% in CN VII-IX, 60% in CN VI, 59% in CN IV, 54% in CN III, 45% in CN V, and 43% in CN II.

Conclusion

In patients with cranial nerve palsies attributed to IAs, the location and rupture status of the aneurysm could determine the type and severity of the nerve palsy. Most patients experienced favorable outcomes in terms of their resolution and long-term function of the CNP after treatment of the IA.

Imaging of cerebrovascular complications from blunt skull base trauma

Cerebrovascular complications from blunt trauma to the skull base, though rare, can lead to potentially devastating outcomes, emphasizing the importance of timely diagnosis and management. Due to the insidious clinical presentation, subtle nature of imaging findings, and complex anatomy of the skull base, diagnosing cerebrovascular injuries and their complications poses considerable challenges. This article offers a comprehensive review of skull base anatomy and pathophysiology pertinent to recognizing cerebrovascular injuries and their complications, up-to-date screening criteria and imaging techniques for assessing these injuries, and a case-based review of the spectrum of cerebrovascular complications arising from skull base trauma. This review will enhance understanding of cerebrovascular injuries and their complications from blunt skull base trauma to facilitate diagnosis and timely treatment.

Stent-assisted coiling of unruptured paraclinoid aneurysms with wide neck or unfavorable dome-to-neck ratio: Results of ventral wall vs dorsal wall with propensity score matching analysis

OBJECTIVE

This study aimed to evaluate the clinical safety and efficacy of stent-assisted coil embolization of unruptured wide-necked paraclinoid aneurysms based on the projection distribution.

METHODS

Between November 2015 and September 2020, 267 unruptured paraclinod aneurysms in 236 patients were identified with a wide neck or unfavorable dome-to-neck ratio and treated with stent-assisted coiling technique. The classification of this segment aneurysms was simplified to the dorsal group (located on the anterior wall) and ventral group (Non-dorsal). Following propensity score matching analysis, the clinical and radiographic data were compared between the two groups.

RESULTS

Among 267 aneurysms, 186 were located on the ventral wall and 81 were on the dorsal wall. Dorsal wall aneurysms had a larger size (p < .001), wider neck (p = .001), and higher dome-to-neck ratio (p = .023) compared with ventral wall aneurysms. Propensity score-matched analysis found that dorsal group had a significantly higher likelihood of unfavorable results in immediate (residual sac, 39.4% vs. 18.2%, p = .007) and follow-up angiography (residual sac, 14.8% vs. 1.9%, p = .037) compared with ventral group, with significant difference in recurrence rates (9.3% vs. 0%, p = .028). The rates of procedure-related complications were not significantly different, but one thromboembolic event occurred in the dorsal group with clinical deterioration.

CONCLUSIONS

Traditional stent-assisted coiling can be given preference in paraclinoid aneurysms located on the ventral wall. The relatively high rate of recurrence in dorsal wall aneurysms with stent assistance may require other treatment options.

Clipping of Bilateral Ophthalmic Artery Aneurysms Through a Single Craniotomy

Bilateral ophthalmic aneurysms are rare and involve two aneurysms in the ophthalmic arteries, one on each, leading to potential symptoms such as vision loss and headaches. The treatment options for aneurysms, ranging from surgery and endovascular embolization to observation, depend on various factors, including aneurysm size and the patient's health. Microsurgery, while presenting complexities due to the intricate anatomy of the anterior clinoid region, offers potential advantages such as enhanced decompression rates and reduced aneurysm recurrence. The presented surgical video illustrates the treatment of bilateral ophthalmic artery aneurysms via a single craniotomy. This method reduces surgical duration and trauma, facilitating quicker patient recovery. However, this method bears potential risks, especially to both optic nerves. As underscored in the video, the utmost anatomical understanding in the anterior clinoid area is pivotal for successful outcomes and reduced complications.

Visual Evoked Potential Can Predict Deterioration of Visual Function After Direct Clipping of Paraclinoid Aneurysm With Anterior Clinoidectomy

BACKGROUND

The role of visual evoked potential (VEP) in direct clipping of the paraclinoid internal carotid artery (ICA) aneurysm remains uncertain.

OBJECTIVE

To examine whether intraoperative neuromonitoring with VEP can predict deterioration of visual function after direct clipping of the paraclinoid ICA aneurysm with anterior clinoidectomy.

METHODS

Among consecutive 274 patients with unruptured cerebral aneurysm, we enrolled 25 patients with paraclinoid ICA aneurysm treated by direct clipping after anterior clinoidectomy with intraoperative neuromonitoring with VEP in this study. We evaluated the visual acuity loss (VAL) and visual field loss (VFL) before surgery, 1 month after surgery, and at the final follow-up.

RESULTS

The VAL at 1 month after surgery (VAL1M) and VAL at the final follow-up (Final VAL) were significantly related to the reduction rate of VEP amplitude at the end of surgery (RedEnd%), more than 76.5%, and the maximal reduction rate of VEP amplitude during surgery (MaxRed%), more than 66.7% to 70%. The VFL at 1 month after surgery (VFL1M) and the VFL at the final follow-up (Final VFL) were significantly related to MaxRed% more than 60.7%.

CONCLUSION

VAL1M, Final VAL, VFL1M, and Final VFL could be significantly predicted by the value of RedEnd% and MaxRed% in direct clipping of Al-Rodhan group Ia, Ib, and II paraclinoid ICA aneurysms with anterior clinoidectomy.

The Extended-Sphenoid Ridge Approach: A New Technique for the Surgical Treatment of Skull Base Tumors in Pediatric Patients

The sphenoid ridge approach (SRA) was initially described as a surgical technique for treating vascular pathologies near the Sylvian fissure. However, limited studies have systematically explored the use of skull base techniques in pediatric patients. This study investigated an extended variation in the sphenoid ridge approach (E-SRA), which systematically removed the pterion, orbital walls (roof and lateral wall), greater sphenoid wing, and anterior clinoid process to access the base of the skull.

OBJECTIVE

This report aimed to evaluate the advantages of the extradural removal of the orbital roof, pterion, sphenoid wing, and anterior clinoid process as a complement to the sphenoid ridge approach in pediatric patients.

PATIENTS AND METHODS

We enrolled 36 patients with suspected neoplastic diseases in different regions. The E-SRA was performed to treat the patients. Patients were included based on the a priori objective of a biopsy or a total gross resection. The surgical time required to complete the approach, associated bleeding, and any complications were documented.

RESULTS

Our results demonstrated that the proposed a priori surgical goal, biopsy, or resection were successfully achieved in all cases. In addition, using the E-SRA technique was associated with a shorter operative time, minimal bleeding, and a lower incidence of complications. The most frequently encountered complications were related to dural closure.

CONCLUSIONS

The extended sphenoid ridge approach represents a safe and effective option for managing intracranial tumors in pediatrics.

Efficacy of 3D evaluation of unruptured paraclinoid aneurysms within Leksell GammaPlan® for determination of their intradural localization

BACKGROUND

Determination of the intradural unruptured paraclinoid aneurysm localization is difficult, but critical for selection of the optimal treatment strategy.

OBJECTIVE

To assess efficacy of the three-dimensional (3D) evaluation of unruptured paraclinoid aneurysms within Leksell GammaPlan® (LGP; Elekta AB; Stockholm, Sweden) for determination of their intradural localization.

METHODS

Overall, 125 incidentally diagnosed unruptured paraclinoid aneurysms in 118 patients (mean age, 55 years) underwent 3D evaluation of their localization within LGP using post-contrast thin-slice constructive interference in steady state (CISS) images, which in 41 cases were additionally co-registered and fused with the axial computed tomography angiography (CTA) source images.

RESULTS

According to the evaluation within LGP, paraclinoid aneurysms were considered intradural, transitional, and extradural in 75, 25, and 25 cases respectively. Overall, 51 of 75 aneurysms deemed to be intradural, underwent microsurgical management, and intraoperative visual inspection confirmed their intradural localization in 45 cases, whereas it was transitional in 3, and extradural in 3. If during preoperative 3D evaluation within LGP only post-contrast CISS images were used, prediction of the pure intradural localization of aneurysm was correct in 88 % of cases (95 % CI: 79-97 %), and of the pure or partial (i.e., transitional) intradural localization in 94 % of cases (95 % CI: 88-100 %), whereas it was 100 % if co-registration and fusion of the contrast-enhanced CISS and CTA source images was done.

CONCLUSION

Intradural localization of the unruptured paraclinoid aneurysms may be effectively predicted based on their 3D evaluation within LGP using post-contrast thin-slice CISS and CTA source images, which may help with clinical decision-making.

Choroidal and retinal anatomical response following treatment of carotid-ophthalmic aneurysms with flow diverter stents

BACKGROUND

Flow diverter stents(FDSs) are recent additions to the endovascular armament for treating ophthalmic segment aneurysms(OSA). In our study we evaluated the long-term effect of FDS placement on multiple Optical Coherence Tomography(OCT) findings, best corrected visual acuity(BCVA) and intra-ocular pressure(IOP).

METHODS

A prospective cohort study was conducted in 35 patients treated with a single FDS placement for OSA, between 2013 and 2018. Spectral-domain OCT was used to measure retinal nerve fiber layer thickness, ganglion cell complex thickness, subfoveal choroidal thickness(SFCT), and other stereometric parameters. Choroidal Vascularity Index(CVI) in a 1.5 mm wide subfoveal choroidal area was calculated. BCVA and IOP were also assessed. These measurements, at final follow up, were compared to the untreated fellow eye to evaluate the long-term effect of FDS placement.

RESULTS

This study included 70 eyes from 35 patients (100% female) with a mean age of 54.9 ± 9.8 years and mean follow-up period of 37.3 ± 18.9 months. No ophthalmic artery occlusion was encountered. The mean CVI was significantly higher in the stented side compared to the fellow normal eye (66.90±1.95 vs 65.05±1.93, p=.001) while mean SFCT was significantly reduced (251.23±68.54 vs 288.78±78.95, p=.037). Differences in the remaining studied parameters did not reach statistical significance. The difference in BCVA between stented and fellow normal eyes was also not significant (0.057±0.213 vs 0.060±0.214, p=.977 in logMAR).

CONCLUSION

Treatment with FDSs did not cause permanent visual damage. This study is the first to report a decrease in SFCT with a compensatory increase in CVI following FDS placement for OSA.

Elongated, finger-like ophthalmic segment aneurysms: Implications for selection of treatment modality

BACKGROUND

Microsurgical treatment of ophthalmic segment aneurysms often requires anterior clinoidectomy and optic nerve mobilization prior to successful clipping.

OBJECTIVE

We hypothesize that ophthalmic segment aneurysms that are elongated and finger-like grow unconstrained, lateral to the optic nerve. We note that this avoids the need for clinoid resection and optic nerve mobilization.

METHODS

Three cases with up-pointing aneurysms were reviewed. Patient and aneurysm characteristics were collected.

RESULTS

The first two patients with elongated ophthalmic segment aneurysms were found to have aneurysms growing lateral to the optic nerve. This allowed for straightforward treatment via microsurgical clipping without anterior clinoidectomy or division of the falciform ligament. The third patient presented with distortion of the optic chiasm superiorly and medially by a giant ventral ICA aneurysm. A concomitant ophthalmic aneurysm in this patient exhibited elongated morphology, with a high-resolution MRI demonstrating the patient's optic nerve was located inferior and medial to the ophthalmic artery aneurysm dome. This supports our hypothesis that an overriding optic nerve normally impedes vertical growth of ophthalmic segment aneurysms.

CONCLUSIONS

Ophthalmic segment aneurysms may acquire a round morphology when their growth is constrained superiorly by the optic nerve. Elongated ophthalmic segment aneurysms may be the result of growth lateral to the optic nerve. For these aneurysms, an anterior clinoidectomy is not required, and microsurgical clipping represents a straightforward treatment option.

Partial medial clinoidectomy with optic canal roof drilling for clipping of ophthalmic artery aneurysms: how I do it

BACKGROUND

Clipping of ophthalmic artery (OA) aneurysms present one of the treatment strategies for long-term disease management. Existing surgical techniques primarily require extra/intradural removal of the anterior clinoid process, carrying a higher risk of infection, damage to surrounding structures or technical complications.

METHODS

We present the technique of minimally invasive partial medial clinoidectomy with the unroofing of the optic canal for surgical clipping of OA aneurysms, and besides its pros and cons, we also discuss proper technical indications.

CONCLUSION

The partial medial clinoidectomy improves manoeuvrability around the paraclinoid region, provides better protection for adjacent structures and renders excellent treatment outcome.

Clinical analysis of cavernous sinus anatomy, pathologies, diagnostics, surgical management and complications - comprehensive review

For decades, the cavernous sinus (CS) has been the subject of debates and scientific studies aimed at elucidating its anatomical variability, and at choosing the best method for accessing it so that optimal diagnoses and related surgical treatments can be decided. The present review considers a series of issues related to the CS. The anatomy of the CS and its features is explored first, and the most important structures, spaces and morphological variations are considered. This is followed by CS pathology and selected diagnostic methods that have proved useful in therapy, and then the management of these pathologies is discussed. Examples of therapeutic steps that have proved helpful in specific cases are taken from the literature. Finally, the various surgical accesses and complications that can be encountered during invasive interventions in the CS area are discussed. The aim of this study is to summarize up-to-date anatomical and clinical knowledge about the CS, citing the most informative scientific papers and aggregating their results. Morphological variations of the CS are common but have not been well described in the literature.

Endovascular treatment of aneurysms of the paraophthalmic segment of the internal carotid artery: Current status

The paraophthalmic segment of the internal carotid artery (ICA) originates from the distal border of the cavernous ICA and terminates at the posterior communicating artery. Aneurysms arising from the paraophthalmic segment represent ~5–10% of intradural aneurysms. Due to the advent of endovascular treatment (EVT) techniques, specifically flow-diverting stents (FDSs), EVT has become a good option for these aneurysms. A literature review on EVT for paraophthalmic segment aneurysms is necessary. In this review, we discuss the anatomy of the paraophthalmic segment, classification of the paraophthalmic segment aneurysms, EVT principle and techniques, and prognosis and complications. EVT techniques for paraophthalmic segment aneurysms include coil embolization, FDSs, covered stents, and Woven EndoBridge devices. Currently, coiling embolization remains the best choice for ruptured paraophthalmic segment aneurysms, especially to avoid long-term antiplatelet therapy for young patients. Due to the excessive use of antiplatelet therapy, unruptured paraophthalmic segment aneurysms that are easy to coil should not be treated with FDS. FDS is appropriate for uncoilable or failed aneurysms. Other devices cannot act as the primary choice but can be useful auxiliary tools. Both coiling embolization and FDS deployment can result in a good prognosis for paraophthalmic segment aneurysms. The overall complication rate is low. Therefore, EVT offers promising treatments for paraophthalmic segment aneurysms. In addition, surgical clipping continues to be a good choice for paraophthalmic segment aneurysms in the endovascular era.

Contralateral vs. Ipsilateral Approach to Superior Hypophyseal Artery Aneurysms: An Anatomical Study and Morphometric Analysis

Introduction

Surgical clipping of superior hypophyseal artery (SHA) aneurysms is a challenging task for neurosurgeons due to their close anatomical relationships. The development of endovascular techniques and the difficulty in surgery have led to a decrease in the number of surgical procedures and thus the experience of neurosurgeons in this region. In this study, we aimed to reveal the microsurgical anatomy of the ipsilateral and contralateral approaches to SHA aneurysms and define their limitations via morphometric analyses of radiological anatomy, three-dimensional (3D) modeling, and surgical illustrations.

Method

Five fixed and injected cadaver heads underwent dissections. In order to make morphometric measurements, 75 cranial MRI scans were reviewed. Cranial scans were rendered with a module and used to produce 3D models of different anatomical structures. In addition, a medical illustration was drawn that shows different sizes of aneurysms and surgical clipping approaches.

Results

For the contralateral approach, pterional craniotomy and sylvian dissection were performed. The contralateral SHA was reached from the prechiasmatic area. The dissected SHA was approached with an aneurysm clip, and maneuverability was evaluated. For the ipsilateral approach, pterional craniotomy and sylvian dissection were performed. The ipsilateral SHA was reached by mobilizing the left optic nerve with left optic nerve unroofing and left anterior clinoidectomy. MRI measurements showed that the area of the prechiasm was 90.4 ± 36.6 mm² (prefixed: 46.9 ± 10.4 mm², normofixed: 84.8 ± 15.7 mm², postfixed: 137.2 ± 19.5 mm², p < 0.001), the distance between the anterior aspect of the optic chiasm and the limbus sphenoidale was 10.0 ± 3.5 mm (prefixed: 5.7 ± 0.8 mm, normofixed: 9.6 ± 1.6 mm, postfixed:14.4 ± 1.6 mm, p < 0.001), and optic nerves’ interneural angle was 65.2° ± 10.0° (prefixed: 77.1° ± 7.3, normofixed: 63.6° ± 7.7°, postfixed: 57.7° ± 5.7°, p: 0.010).

Conclusion

Anatomic dissections along with 3D virtual model simulations and illustrations demonstrated that the contralateral approach would potentially allow for proximal control and neck control/clipping in smaller SHA aneurysm with relatively minimal retraction of the contralateral optic nerve in the setting of pre- or normofixed chiasm, and ipsilateral approach requires anterior clinodectomy and optic unroofing with considerable optic nerve mobilization to control proximal ICA and clip the aneurysm neck effectively.

Incomplete occlusion and visual symptoms of peri-ophthalmic aneurysm after treatment with a pipeline embolization device: a multi-center cohort study

OBJECTIVE

Peri-ophthalmic aneurysm is a special type of aneurysm. We assessed the relationship between ophthalmic artery (OA) origin and aneurysm and examined the effect of a pipeline embolization device (PED, Covidien/Medtronic) with or without coils on aneurysm occlusion rate and visual outcomes.

METHODS

We retrospectively analyzed 194 peri-ophthalmic aneurysms in 189 patients among 1171 patients treated with a PED in a Chinese post-market multi-center registry study from November 2014 to October 2019. Peri-ophthalmic aneurysms were defined as carotid-ophthalmic segment aneurysms arising from the internal carotid artery dorsal wall at, or distal to, the OA origin, with a superior or superomedial projection. The relationship between OA origin and the aneurysm was classified as follows: type A, OA originating separate from the aneurysm; type B, OA originating from the aneurysm neck or dome. Patients with aneurysm were divided into the PED-only group and the PED + coils group according to treatment.

RESULTS

The median follow-up time was 6.8 months (range, 5.3-20.2 months). There were 163 occluded aneurysms (84%) and 31 aneurysms with incomplete occlusion (16%). A multivariate analysis showed that type B aneurysm was a risk factor for incomplete occlusion in the PED-only group (odds ratio [OR] 4.854, 95% confidence interval [CI] 1.878-12.548, P = 0.001). Visual symptoms at final follow-up correlated with preoperative visual symptoms (OR 22.777, 95% CI 3.115-166.555, P = 0.002).

CONCLUSIONS

Type B aneurysm is associated with a lower occlusion rate after PED-only treatment. Patients with preoperative visual symptoms should be treated promptly to avoid permanent visual symptoms.

A comparative propensity-adjusted analysis of microsurgical versus endovascular treatment of unruptured ophthalmic artery aneurysms

OBJECTIVE

Ophthalmic artery (OA) aneurysms are surgically challenging lesions that are now mostly treated using endovascular procedures. However, in specialized tertiary care centers with experienced neurosurgeons, controversy remains regarding the optimal treatment of these lesions. This study used propensity adjustment to compare microsurgical and endovascular treatment of unruptured OA aneurysms in experienced tertiary and quaternary settings.

METHODS

The authors retrospectively reviewed the medical records of all patients who underwent microsurgical treatment of an unruptured OA aneurysm at the University of California, San Francisco, from 1997 to 2017 and either microsurgical or endovascular treatment at Barrow Neurological Institute from 2011 to 2019. Patients were categorized into two cohorts for comparison: those who underwent open microsurgical clipping, and those who underwent endovascular flow diversion or coil embolization. Outcomes included neurological or visual outcomes, residual or recurrent aneurysms, retreatment, and severe complications.

RESULTS

A total of 345 procedures were analyzed: 247 open microsurgical clipping procedures (72%) and 98 endovascular procedures (28%). Of the 98 endovascular procedures, 16 (16%) were treated with primary coil embolization and 82 (84%) with flow diversion. After propensity adjustment, microsurgical treatment was associated with higher odds of a visual deficit (OR 8.5, 95% CI 1.1-64.9, p = 0.04) but lower odds of residual aneurysm (OR 0.06, 95% CI 0.01-0.28, p < 0.001) or retreatment (OR 0.12, 95% CI 0.02-0.58, p = 0.008) than endovascular therapy. No difference was found between the two cohorts with regard to worse modified Rankin Scale score, modified Rankin Scale score greater than 2, or severe complications.

CONCLUSIONS

Compared with endovascular therapy, microsurgical clipping of unruptured OA aneurysms is associated with a higher rate of visual deficits but a lower rate of residual and recurrent aneurysms. In centers experienced with both open microsurgical and endovascular treatment of these lesions, the treatment choice should be based on patient preference and aneurysm morphology.

Sella turcica bridging: a systematic review

PURPOSE

Sella turcica bridging (STB) has significant implications during neurosurgery, since it alters regional anatomy; however, no studies have investigated the global prevalence of STB. Our systematic review aimed to establish the global prevalence of STB, in specimens/individuals with and without comorbidities, in males and females, and of partial, complete, unilateral, and bilateral bridging.

METHODS

A literature search was conducted in MEDLINE/PubMed, ScienceDirect, and Google Scholar with various key words relating to Sella turcica bridging. Quantitative data were extracted and statistically analysed.

RESULTS

Eighty-two studies satisfied our inclusion criteria. The mean prevalence of STB was 26.54%, and most prevalent in Europe. STB was detected more frequently using radiological investigations. STB was less prevalent in healthy individuals (21.12%) when compared to individuals with comorbidities (33.31%). Partial STB was found to be the more prevalent in both individuals with (41.06%) and without (21.55%) comorbidities. The prevalence of unilateral and bilateral STB was only studied in healthy individuals, with unilateral bridging being the more prevalent (6.26% vs 3.84%).

CONCLUSION

The global overall prevalence of Sella turcica bridging in the general population was found to be higher than previously thought. Anatomical and embryological textbooks should consider including information on STB in their texts, due to its considerable prevalence and effects to the regional anatomy.

The diagnostic accuracy of MRI in determining the relations between paraclinoid aneurysms and the cavernous sinus

Purpose

The location of paraclinoid aneurysms is determinant for evaluation of its intradural compartment and risk of SAH after rupture. Advanced MRI techniques have provided clear visualization of the distal dural ring (DDR) to determine whether an aneurysm is intracavernous, transitional or intradural for decision-making. We analyzed the diagnostic accuracy of MRI in predicting whether a paraclinoid aneurysm is intracavernous, transitional or intradural.

Methods

We conducted a prospective cohort between January 2014 and December 2018. Patients with paraclinoid aneurysms underwent 3D fast spin-echo MRI sequence before surgical treatment. The DDR was the landmark for MRI characterization of the aneurysms as follow: (i) Intradural; (ii) Transitional; and (iii) Intracavernous. The MRI sensitivity, specificity, positive and negative likelihood ratios were determined compared to the intraoperative findings. We also evaluated the intertechnique agreement using the Cohen’s kappa coefficient (κ) for dichotomous classifications (cavernous vs non-cavernous).

Results

Twenty patients were included in the cohort. The accuracy of MRI showed a sensitivity of 86.7% (95%CI:59.5–98.3) and specificity of 90.0% (95%CI:55.5–99.8). Analyzing only patients without history of SAH, accuracy test improved with a sensitivity of 92.3% (95%CI:63.9–99.8) and specificity reached 100% (95%CI: 63–100). Values of Cohen’s kappa (κ), intertechnique agreement was considered substantial for dichotomous classifications (κ = 0.754; p < 0.001). For patients without previous SAH, intertechnique agreement was even more coincident for the dichotomous classification (κ = 0.901; p < 0.001).

Conclusion

3D fast spin-echo MRI sequence is a reliable and useful technique for determining the location of paraclinoid aneurysms in relation to the cavernous sinus, particularly for patients with no history of SAH.

Ophthalmic Segment Aneurysms: Surgical Treatment and Outcomes

Background  Surgical treatment of ophthalmic segment aneurysms (OSAs) remain challenging because of complex anatomy surrounding the aneurysm and entails extensive drilling of anterior clinoid process to define proximal neck of the aneurysm and carotid exposure in the neck for proximal control. Materials and Methods  Authors present a retrospective analysis of 36 aneurysms in 35 patients with OSAs operated surgically by first author. Surgical clipping was done for the aneurysms as primary modality of treatment along with wrapping and trapping as required. Results  Commonest age group was 40 to 60 years with female preponderance of 3:1. Maximum (23) patients presented with subarachnoid hemorrhage (WFNS Gr 1), followed by asymptomatic patients (six). There were 18 small, 14 large, and four giant aneurysms, 15 dorsal wall, 17 ventral wall, three proximal posterior wall, and one blister aneurysm. Good outcome, as measured by Glasgow Outcome Score (GOS) was achieved in 29 patients. Conclusion  OSAs are technically demanding aneurysms, but with due diligence to surgical principles, good outcomes may be obtained.

Contralateral interoptic approach to paraclinoid aneurysms: a patient-selection algorithm based on anatomical investigation and clinical validation

OBJECTIVE

Aneurysms that arise on the medial surface of the paraclinoid segment of the internal carotid artery (ICA) are surgically challenging. The contralateral interoptic trajectory, which uses the space between the optic nerves, can partially expose the medial surface of the paraclinoid ICA. In this study, the authors quantitatively measure the area of the medial ICA accessible through the interoptic triangle and propose a potential patient-selection algorithm that is based on preoperative measurements on angiographic imaging.

METHODS

The contralateral interoptic trajectory was studied on 10 sides of 5 cadaveric heads, through which the medial paraclinoid ICA was identified. The falciform ligament medial to the contralateral optic canal was incised, the contralateral optic nerve was gently elevated, and the medial surface of the paraclinoid ICA was inspected via different viewing angles to obtain maximal exposure. The accessible area on the carotid artery was outlined. The distance from the distal dural ring (DDR) to the proximal and distal borders of this accessible area was measured. The superior and inferior borders were measured using the clockface method relative to a vertical line on the coronal plane. To validate these parameters, preoperative measurements and intraoperative findings were reviewed in 8 clinical cases.

RESULTS

In the sagittal plane, the mean (SD) distances from the DDR to the proximal and distal ends of the accessible area on the paraclinoid ICA were 2.5 (1.52) mm and 8.4 (2.32) mm, respectively. In the coronal plane, the mean (SD) angles of the superior and inferior ends of the accessible area relative to a vertical line were 21.7° (14.84°) and 130.9° (12.75°), respectively. Six (75%) of 8 clinical cases were consistent with the proposed patient-selection algorithm.

CONCLUSIONS

The contralateral interoptic approach is a feasible route to access aneurysms that arise from the medial paraclinoid ICA. An aneurysm can be safely clipped via the contralateral interoptic trajectory if 1) both proximal and distal borders of the aneurysm neck are 2.5-8.4 mm distal to the DDR, and 2) at least one border of the aneurysm neck on the coronal clockface is 21.7°-130.9° medial to the vertical line.

Unruptured Paraclinoid Carotid Aneurysms Occur More Frequently in Younger Ages

Purpose

We investigated the age distribution of cerebral saccular aneurysms in various locations to clarify the differences by location and discuss the mechanism of formation.

Materials and Methods

We retrospectively assessed clinical material obtained from 1,252 unruptured aneurysms treated with endovascular embolization between 2004 and 2019. Age, sex, laterality, and size were investigated by the location of aneurysms, classified as cavernous internal carotid artery (ICA), paraclinoid ICA, supraclinoid ICA, anterior communicating artery, anterior cerebral artery, middle cerebral artery, basilar artery complex, and posterior inferior cerebellar artery. Paraclinoid aneurysms were subclassified into 3 patterns according to their projecting direction: S-type, with superior protrusion; M-type, with medial protrusion; and P-type, with posteroinferior protrusion.

Results

There was no significant difference by location for sex, laterality, and size. The mean age of patients with paraclinoid aneurysms (56.5 years old) was significantly lower than that of other aneurysm patients (64.3 years old). Notably, 40% of the patients with M-type aneurysms were <50 years old. This percentage was significantly higher than that of aneurysms at other locations (P<0.05).

Conclusion

We found a young female predominance for patients with paraclinoid carotid aneurysms. This study may suggest that congenital factors contribute to paraclinoid aneurysm formation as well acquired factors, such as hemodynamic stress, atherosclerotic wall damage, and local inflammation.

Flow-diverting devices in the treatment of unruptured ophthalmic segment aneurysms at a mean clinical follow-up of 5 years

A shift toward the endovascular treatment of ophthalmic segment aneurysms is noticeable. However, it is not clear if the long-term treatment results improve with the development of endovascular methods. The aim of this study was to present the outcomes of the treatment of unruptured ophthalmic aneurysms using flow diverting devices (FDD) with or without coiling. This retrospective study included 52 patients with 65 UIAs treated in 2009–2016. The mean aneurysm size was 8.8 mm. Eight aneurysms were symptomatic. Therapeutic procedures included: 5 failed attempts, 55 first sessions with FDD deployment (bilateral procedures in 3) and 3 retreatment procedures. To cover 55 ICAs, 25 Silk, 26 Pipeline, 9 Fred and 1 Surpass FDD were used. FDD with coiling was applied in 19(29.2%), mainly for symptomatic and larger aneurysms. Mean radiological and clinical follow-up was 12 and 61 months, respectively. Postprocedural deterioration was noted in 3(5.8%) patients, but in long-term the modified Rankin Scale grades 0–2 were achieved in 98.1% of patients. One patient died from the treated aneurysm rupture (annual risk—0.07%). Raymond–Roy occlusion classification class I or II was achieved in 98.5% in the long term, with similar results in both groups. Complications occurred in 40.4% of patients and the most frequent were: imperfect FDD deployment (15%), failed attempt of FDD deployment (9.6%) and late FDD stenosis (9.6%). Flow-diverting devices, with additional coiling in selected cases, may offer a very high proportion of satisfactory outcomes. However, in our experience the high risk of complications remains.

Balloon-Assisted Coils Embolization for Ophthalmic Segment Aneurysms of the Internal Carotid Artery

Objective: To explore the role of balloon-assisted coils technique for ophthalmic segment aneurysms (OSAS).

Methods: Clinical data of 30 patients with OSAS were reviewed between December 2017 and December 2018. OSAS were defined as arising from the internal carotid artery (ICA), reaching from the distal dural ring to the origin of the posterior communicating artery. OSAS were classified into four types based on the angiographic findings. The balloon-assisted coils technique was used for the embolization of aneurysms. The duration of balloon inflation cycles, as well as difficulty and complications during the embolization procedure, were recorded. The immediate angiographic results were evaluated according to the Raymond scale. Clinical results were evaluated based on the MRS score. Follow-ups were performed at 18 months post-embolization by DSA or MRA at our institution.

Results: Thirty-two aneurysms in 30 patients were detected by digital subtraction angiography (DSA), which included 30 unruptured and two ruptured cases. The patients with ruptured aneurysms were grade II status according to the Hunt-Hess scale. Three cases were type A, nine cases were type B, 17 cases were type C, and three cases were type D. According to aneurysm size, there were 19 cases of small, 11 cases of medium, two cases of large aneurysm. Thirty-two aneurysms were successfully embolized in 30 patients by balloon-assisted coils technique. The ophthalmic artery could be protected by an engorged balloon in the procedure, especially for type A aneurysms. Considering that type D aneurysm arises from the side-wall of the artery and near to tortuous ICA siphon, the balloon catheter was inflated to stabilize the microcatheter allowing for overinflation when necessary. The average duration of balloon dilatation was 4 min, and the average time was 2.5 times. Raymond class was one in 28 aneurysms and two in four aneurysms according to the immediate post-embolization angiographic results. All the patients achieved good clinical effects, except for one patient who presented with brain ischemia resulting in dizziness and contralateral limb weakness for 10 h due to prolonged temporary clamping of the responsible ICA. The follow-up angiography results were satisfactory at 18 months post-embolization.

Conclusion: OSAS endovascular treatment with balloon-assisted coils has different advantages in a different classification. The technique is safe, effective, and relatively inexpensive, especially for small and medium OSAS.

Microsurgical Clipping Techniques and Outcomes for Paraclinoid Internal Carotid Artery Aneurysms

BACKGROUND

Microsurgical clipping of paraclinoid aneurysms presents unique technical challenges because of the anatomical complexity of the paraclinoid region.

OBJECTIVE

To analyze microsurgical clipping techniques, complications, and outcomes associated with paraclinoid aneurysms, with a focus on clip selection and clipping technique according to aneurysm location.

METHODS

From 1997 to 2016, 231 unruptured paraclinoid aneurysms from 216 patients were treated using microsurgical clipping. We retrospectively reviewed patient records to analyze clinical outcomes.

RESULTS

A total of 80 aneurysms (34.6%) were treated with simple clipping. Among them, fenestrated clips were used with superior hypophyseal artery (SHA) aneurysms, but curved clips were used with most other aneurysms. A total of 151 aneurysms (65.6%) were treated using multiple clips, including tandem clipping for ophthalmic artery (OphA) aneurysms, tandem angled-fenestrated clipping for SHA and ventral carotid aneurysms, stacked clipping for dorsal carotid aneurysms, and various techniques for clinoidal segment/carotid cave aneurysms. Postoperative angiography was performed in 214 aneurysms (92.6%), and complete obliteration was confirmed in 195 aneurysms (91.1%). Using the modified Rankin Scale (mRS), overall functional outcome was good (mRS 0-2) in 99.6% of patients, although 30 cases (13.0%) showed new postoperative visual deficits.

CONCLUSION

Surgical clipping of paraclinoid aneurysms is an excellent treatment modality with good clinical outcomes and acceptable complication rates, particularly in centers with large experience in the microsurgical management of cerebrovascular disorders. Appropriate clip selection and clipping techniques are required to perform complete and safe clipping.

Endovascular Treatment for Lateral Wall Paraclinoid Aneurysms and the Influence of Internal Carotid Artery Angle

Lateral wall paraclinoid aneurysms (LPA) are a rare type of aneurysm located on the lesser curve side of the internal carotid artery (ICA) bend, at the level of the anterior clinoid process. The objective of this study was to assess the influence of flexion of the ICA on the morphology of aneurysms and outcome of endovascular treatment. Between 2003 and 2018, we treated 643 cases of unruptured paraclinoid aneurysms with endovascular therapy in our institution. Of those cases, aneurysms projecting laterally on preoperative angiography were defined as LPA. The degree of bending of the ICA (ICA angle) was measured and statistically analyzed in relation to the aneurysm characteristics and the occlusion status after treatment. In all, 43 aneurysms were identified. ICA angle was positively correlated with the maximum dome size of the aneurysm (P <0.01) and the aspect ratio (P <0.01), and negatively correlated with the volume coil embolization ratio (P <0.01). Complete occlusion (CO) was achieved in 23 cases (53.5%) immediately after treatment, and in 35 cases (81.4%) at follow-up. The mean ICA angle in the incomplete occlusion group was significantly larger than in the CO group (P = 0.01). Larger ICA angle resulted in recurrence, whereas smaller ICA angle was more likely to obtain progressive thrombosis (P = 0.02). Endovascular treatment for LPA was safe and effective. The degree of flexion of the ICA may contribute to the level of hemodynamic stress on the aneurysm, its morphology, and the embolization effect.

A scoring system to discriminate blood blister-like aneurysms: a multidimensional study using patient-specific model

Presurgical discrimination of blood blister-like aneurysms (BBAs) can assist neurosurgeons in clinical decision-making. The aim of this study was to investigate the characteristics of BBAs and construct a useful tool to distinguish BBAs. This study reviewed patients with small/median, hemispherical, and wide-necked aneurysms of the internal carotid artery in our institution. BBAs were identified via their intraoperative findings. A hemodynamic analysis was performed using a patient-specific model. The independent risk factors of BBAs were investigated using a logistic analysis. A scoring system was then established to discriminate BBAs, in which its predicting value was analyzed using receiver operating characteristic (ROC) analysis. A total of 67 aneurysms comprising 21 BBAs were enrolled. Comparing features between BBAs and non-BBAs, statistical significances were found in the aspect ratio (AR), height-to-width ratio, aneurysm angle (AA), wall shear stress gradient (WSSG), and normalized wall shear stress average. A multivariate logistic analysis identified AR (OR = 0.29, p = 0.021), WSSG (OR = 1.54, p = 0.017) and AA (OR = 2.49, p = 0.039) as independent risk factors for BBAs. A scoring system was constructed using these parameters, effectively distinguishing BBAs (AUC = 0.931, p < 0.01). Our multidimensional scoring system may effectively assist in the discrimination of BBAs from wide-necked non-BBAs.

Predictor of Visual Impairment Following Paraclinoid Aneurysm Surgery: Special Consideration of Surgical Microanatomy Related to Paraclinoid Structures

BACKGROUND

Microsurgical clipping with extradural anterior clinoidectomy (EDAC) for paraclinoid aneurysm is an established technique with good angiographic outcomes, although postoperative worsening of visual acuity remains a concern. Multiple reports show visual acuity deteriorating after clipping, yet the cause remains unclear.

OBJECTIVE

To analyze results of asymptomatic paraclinoid aneurysm surgeries treated with EDACs, specifically focusing on the microanatomy of paraclinoid structure dissection. This determined the causes of delayed visual impairment and microsurgical indications.

METHODS

Results of the treatment with EDAC of 94 patients with cerebral aneurysm and normal preoperative visual acuity but also full visual fields were retrospectively analyzed.

RESULTS

The mean aneurysm size was 6.2 (±3.3) mm. Clipping was performed in 87 cases and trapping in 7 cases. Complete angiographic occlusion was observed in 91 patients. In 26 cases, a postoperative visual deficit occurred. A total of 20 cases exhibited partial visual field deficits, including 5 who were asymptomatic. Visual deficits were only detectable by postoperative ophthalmologic testing. Six showed light perception impairment or blinding. Of the 15 patients with symptomatic partial visual field deficits, 5 showed improvement at follow-up. Visual deficits persisted in 22 patients at the last follow-up. Multivariate logistic regression analysis revealed that medial projecting aneurysm (adjusted odds ratio [OR]: 10.43) and the opening of the carotidoculomotor membrane (adjusted OR: 5.19) were significantly related to visual impairment.

CONCLUSION

Excess dissection of carotidoculomotor membranes causes postoperative delayed visual worsening. For treating small, asymptomatic paraclinoid aneurysms, carotidoculomotor membranes should not be opened, and microsurgical clipping should not be performed for preoperative asymptomatic medial projecting aneurysms.

Fully automated detection and segmentation of intracranial aneurysms in subarachnoid hemorrhage on CTA using deep learning

In aneurysmal subarachnoid hemorrhage (aSAH), accurate diagnosis of aneurysm is essential for subsequent treatment to prevent rebleeding. However, aneurysm detection proves to be challenging and time-consuming. The purpose of this study was to develop and evaluate a deep learning model (DLM) to automatically detect and segment aneurysms in patients with aSAH on computed tomography angiography. In this retrospective single-center study, three different DLMs were trained on 68 patients with 79 aneurysms treated for aSAH (2016–2017) using five-fold-cross-validation. Their outputs were combined to a single DLM via ensemble-learning. The DLM was evaluated on an independent test set consisting of 185 patients with 215 aneurysms (2010–2015). Independent manual segmentations of aneurysms in a 3D voxel-wise manner by two readers (neurosurgeon, radiologist) provided the reference standard. For aneurysms > 30 mm³ (mean diameter of ~ 4 mm) on the test set, the DLM provided a detection sensitivity of 87% with false positives (FPs)/scan of 0.42. Automatic segmentations achieved a median dice similarity coefficient (DSC) of 0.80 compared to the reference standard. Aneurysm location (anterior vs. posterior circulation; P = .07) and bleeding severity (Fisher grade ≤ 3 vs. 4; P = .33) did not impede detection sensitivity or segmentation performance. For aneurysms > 100 mm³ (mean diameter of ~ 6 mm), a sensitivity of 96% with DSC of 0.87 and FPs/scan of 0.14 were obtained. In the present study, we demonstrate that the proposed DLM detects and segments aneurysms > 30 mm³ in patients with aSAH with high sensitivity independent of cerebral circulation and bleeding severity while producing FP findings of less than one per scan. Hence, the DLM can potentially assist treating physicians in aSAH by providing automated detection and segmentations of aneurysms.

Application of hybrid operating rooms for clipping large or giant intracranial carotid-ophthalmic aneurysms

BACKGROUND

A hybrid operating room (Hybrid-OR) is a surgical theatre that combines a conventional operating room with advanced medical imaging devices. There are still plenty of limitations when endovascular treatment or microsurgical treatment is used individually to treat large or giant carotid-ophthalmic aneurysms.

AIM

To explore and summarize the technical features and effectiveness of the application of a Hybrid-OR in managing major intracranial carotid-ophthalmic aneurysms.

METHODS

The Department of Neurosurgery treated 12 cases of large or giant intracranial carotid-ophthalmic aneurysms between March 2013 and December 2019 in a Hybrid-OR. All cases were treated with clipping and parent vessel reconstruction.

RESULTS

With the assistance of the Hybrid-OR, the rate of incomplete intraoperative aneurysm clipping decreased from 25% (3/12) to 0%, while the rate of vessel stenosis decreased from 16.7% (2/12) to 8.35% (1/12). In terms of thromboembolic events, ischemic infarction complication occurred in only one patient, and none of the patients experienced embolic infarction complications. All 12 patients were followed for an average of 3 years, and no aneurysms recurred. The postoperative recovery was evaluated with the modified Rankin Scale (mRS): 11 patients showed no symptoms (mRS = 0), 1 patient showed slight disability (mRS 1-2), and none of the patients had severe disability (mRS = 5) or died (mRS = 6).

CONCLUSION

The Hybrid-OR provides new ideas for the surgical clipping of large or giant intracranial carotid-ophthalmic aneurysms and decreases the rate of intraoperative vessel stenosis and unsuccessful clipping.

Reproducibility of a new classification of the anterior clinoid process of the sphenoid bone

BACKGROUND

Pneumatization of the anterior clinoid process (ACP) affects paraclinoid region surgery, this anatomical variation occurs in 6.6-27.7% of individuals, making its preoperative recognition essential given the need for correction based on the anatomy of the pneumatized process. This study was conducted to evaluate the reproducibility of an optic strut-based ACP pneumatization classification by presenting radiological examinations to a group of surgeons.

METHODS

Thirty cranial computer tomography (CT) scans performed from 2013 to 2014 were selected for analysis by neurosurgery residents and neurosurgeons. The evaluators received Google Forms with questionnaires on each scan, DICOM files to be manipulated in the Horos software for multiplanar reconstruction, and a collection of slides demonstrating the steps for classifying each type of ACP pneumatization. Interobserver agreement was calculated by the Fleiss kappa test.

RESULTS

Thirty CT scans were analyzed by 37 evaluators, of whom 20 were neurosurgery residents and 17 were neurosurgeons. The overall reproducibility of the ACP pneumatization classification showed a Fleiss kappa index of 0.49 (95% confidence interval: 0.49-0.50). The interobserver agreement indices for the residents and neurosurgeons were 0.52 (0.51-0.53) and 0.49 (0.48-0.50), respectively, and the difference was statistically significant (P < 0.00001).

CONCLUSION

The optic strut-based classification of ACP pneumatization showed acceptable concordance. Minor differences were observed in the agreement between the residents and neurosurgeons. These differences could be explained by the residents' presumably higher familiarity with multiplanar reconstruction software.

Surgical clipping of ophthalmic artery aneurysms: a single center series

AIM

The purpose of this study was to summary the characteristics of ophthalmic artery (OphA) aneurysms and to obtain the independent risk factors for poor prognosis of microsurgical clipping treatment for OphA aneurysms.

METHODS

The clinical and microsurgical clipping results of all 63 patients with ophthalmic aneurysm were investigated and reviewed. The OphA aneurysm patient's case records were reviewed including clinical characteristics, image findings, and clinical outcomes. Then, the risk factors of poor prognosis were analyzed retrospectively.

RESULTS

Monocular blindness persisted in 4 patients (6.35%), 1 patient developed persistent vegetate state (PVS) (1.59%), while 4 patients (6.35%) died. The matching process constructed a cohort consisting of 9 poor outcome (Glasgow Outcome Scale, GOS 1-3) patients (14.3%), and 54 good outcome (GOS 4-5) patients (85.7%). Univariate analysis between the good outcome and poor outcome revealed statistical significance in age > 60 (p = 0.045), size (p = 0.016), and rupture before operation (p = 0.049). Further, multivariate logistic regression analysis identified age > 60 (odds ratio [OR], 5.877; 95% confidence interval [CI], 1.039-33.254; p = 0.045) and aneurysm size > 10mm (OR, 9.417; 95% CI, 1.476-60.072; p = 0.018) as the independent risk factors for poor outcome in microsurgical clipping treatment for OphA aneurysms.

CONCLUSION

The significant independent risk factors associated with clipping OphA aneurysms are age (>60) and size (>10mm).

Visual Outcomes after Surgery for Paraclinoid Aneurysms: A Fujita Experience

INTRODUCTION

The surgical strategies for clipping of paraclinoid aneurysms are diverse. These aneurysms are unique in their location, as they closely abut the anterior clinoid process (ACP) and the optic nerve. The ultimate goal of clipping encompasses the exposure of neck of the aneurysm which is seldom complete without the manipulation of optic nerve and the ACP. This manipulation may result in disturbances of vision postoperatively. We analyze our results of visual outcomes in the surgery for paraclinoid aneurysms in this retrospective study.

MATERIALS AND METHODS

All patients with paraclinoid aneurysms who underwent surgery from June 2014 to June 2019 were included in the study. Surgical procedure was uniform in all patients which included anterior clinoidectomy and clipping of aneurysms as per the Bantane protocol. Glasgow Outcome Scale as well as vision was assessed at discharge and at 1 month and 6 months.

RESULTS

There were 77 cases of paraclinoid aneurysms operated during the abovementioned period. All patients had no symptoms related to vision preoperatively. Visual deterioration was noted in two patients. All patients were discharged with a good outcome on the Glasgow Outcome Scale.

CONCLUSION

Paraclinoid aneurysm has a good outcome when treated with surgery. The visual deterioration following surgery can be minimized with extradural anterior clinoidectomy and careful handling of the vessels and nerve.

Anatomical assessment of the endoscopic endonasal approach for the treatment of paraclinoid aneurysms

OBJECTIVE

Endoscopic endonasal approaches (EEAs) are increasingly being incorporated into the neurosurgeon's armamentarium for treatment of various pathologies, including paraclinoid aneurysms. However, few anatomical assessments have been performed on the use of EEA for this purpose. The aim of the present study was to provide a comprehensive anatomical assessment of the EEA for the treatment of paraclinoid aneurysms.

METHODS

Five cadaveric heads underwent an endonasal transplanum-transtuberculum approach to expose the paraclinoid area. The feasibility of obtaining proximal and distal internal carotid artery (ICA) control as well as the topographic location of the origin of the ophthalmic artery (OphA) relative to dural landmarks were assessed. Limitations of the EEA in exposing the supraclinoid ICA were also recorded to identify favorable paraclinoid ICA aneurysm projections for EEA.

RESULTS

The extracavernous paraclival and clinoidal ICAs were favorable segments for establishing proximal control. Clipping the extracavernous ICA risked injury to the trigeminal and abducens nerves, whereas clipping the clinoidal segment put the oculomotor nerve at risk. The OphA origin was found within 4 mm of the medial opticocarotid point on a line connecting the midtubercular recess point to the medial vertex of the lateral opticocarotid recess. An average 7.2-mm length of the supraclinoid ICA could be safely clipped for distal control. Assessments showed that small superiorly or medially projecting aneurysms were favorable candidates for clipping via EEA.

CONCLUSIONS

When used for paraclinoid aneurysms, the EEA carries certain risks to adjacent neurovascular structures during proximal control, dural opening, and distal control. While some authors have promoted this approach as feasible, this work demonstrates that it has significant limitations and may only be appropriate in highly selected cases that are not amenable to coiling or clipping. Further clinical experience with this approach helps to delineate its risks and benefits.

Concomitant occurrence of clinoid and cavernous segment aneurysms complicated with carotid cavernous fistula: A case report

RATIONALE

Dual aneurysms arising from the internal cerotic artery (ICA) is a very rare occurrence. Clinoid segment aneurysms (CSAs) are often seen at the carotid dural rings while cavernous carotid aneurysms (CCAs) are often a direct communication between the ICA and the cavernous sinus (CS). We present a case of complex concomitant occurrence of a CSA and a CCA complicated with delay aneurysmal rupture (DAR) resulting in carotid cavernous fistula (CCF) after our initial treatment of the patient with pipeline embolization devices (PLEDs) PATIENT CONCERNS:: We present a 64-year old female who we admitted at our institution due to one-year history of double vision. Neurological examinations were unremarkable.

DIAGNOSIS

Magnetic resonance imaging (MRI) and computer tomography (CT)-scan revealed dual aneurysms on the ICA. Digital subtracting angiogram (DSA) confirmed a small CSA and a large CCA on the right ICA.

INTERVENTIONS

We treated both aneurysms with PLED and subsequently observed DAR of CCA as a complication.

OUTCOMES

We successfully occluded the fistula with ONYX (ev3, Irvine, CA) via the trans-venous approach.

LESIONS

PLED was the best endovascular treatment option though DAR was inevitable. Although the trans-arterial approach may be the gold standard for the managing of CCF, the complex nature of our case made us opt for trans-venous approach. The trans-venous route is very appropriate for fistulas with complex parent arteries.

The approach angle to the interoptic triangle limits surgical workspace when targeting the contralateral internal carotid artery

BACKGROUND

The interoptic triangle (IOT) offers a key access to the contralateral carotid artery's ophthalmic segment (oICA) and its perforating branches (PB), the ophthalmic artery (OA), and the superior hypophyseal artery (SHA). It has been previously reported that the assessment of IOT's size is relevant when attempting approaches to the contralateral oICA. However, previous studies have overseen that, since the oICA is a paramedian structure and a lateralized contralateral approach trajectory is then required, the real access to the oICA is further limited by the approach angle adopted by the surgeon with respect to the IOT's plane. For this reason, we determined the surgical accessibility to the contralateral oICA and its branches though the IOT by characterizing the morphometry of this triangle relative to the optimal contralateral approach angle.

METHODS

We defined the "relative interoptic triangle" (rIOT) as the two-dimensional projection of the IOT to the surgeon's view, when the microscope has been positioned with a certain angle with respect to the midline to allow the maximal contralateral oICA visualization. We correlated the surface of the rIOT to the visualization of oICA, OA, SHA, and PBs on 8 cadavers and 10 clinical datasets, using for the last a 3D-virtual reality system.

RESULTS

A larger rIOT correlated positively with the exposure of the contralateral oICA (R = 0.967, p < 0.001), OA (R = 0.92, p < 0.001), SHA (R = 0.917, p < 0.001), and the number of perforant vessels of the oICA visible (R = 0.862, p < 0.001). The exposed length of oICA, OA, SHA, and number PB observed increased as rIOT's surface enlarged. The correlation patterns observed by virtual 3D-planning matched the anatomical findings closely.

CONCLUSIONS

The exposure of contralateral oICA, OA, SHA, and PB directly correlates to rIOT's surface. Therefore, preoperative assessment of rIOT's surface is helpful when considering contralateral approaches to the oICA. A virtual 3D planning tool greatly facilitates this assessment.

Comparison of flow diversion with clipping and coiling for the treatment of paraclinoid aneurysms in 115 patients

OBJECTIVE

Paraclinoid aneurysms represent approximately 5% of intracranial aneurysms (Drake et al. [1968]). Visual impairment, which occurs in 16%-40% of patients, is among the most common presentations of these aneurysms (Day [1990], Lai and Morgan [2013], Sahlein et al. [2015], and Silva et al. [2017]). Flow-diverting stents, such as the Pipeline Embolization Device (PED), are increasingly used to treat these aneurysms, in part because of their theoretical reduction of mass effect (Fiorella et al. [2009]). Limited data on paraclinoid aneurysms treated with a PED exist, and few studies have compared outcomes of patients after PED placement with those of patients after clipping or coiling.

METHODS

The authors performed a retrospective analysis of 115 patients with an aneurysm of the cavernous to ophthalmic segments of the internal carotid artery treated with clipping, coiling, or PED deployment between January 2011 and March 2017. Postoperative complications were defined as new neurological deficit, aneurysm rupture, recanalization, or other any operative complication that required reintervention.

RESULTS

A total of 125 paraclinoid aneurysms in 115 patients were treated, including 70 with PED placement, 23 with coiling, and 32 with clipping. Eighteen (14%) aneurysms were ruptured. The mean aneurysm size was 8.2 mm, and the mean follow-up duration was 18.4 months. Most aneurysms were discovered incidentally, but visual impairment, which occurred in 21 (18%) patients, was the most common presenting symptom. Among these patients, 15 (71%) experienced improvement in their visual symptoms after treatment, including 14 (93%) of these 15 patients who were treated with PED deployment. Complete angiographic occlusion was achieved in 89% of the patients. Complications were seen in 17 (15%) patients, including 10 (16%) after PED placement, 2 (9%) after coiling, and 5 (17%) after clipping. Patients with incomplete aneurysm occlusion had a higher rate of procedural complications than those with complete occlusion (p = 0.02). The rate of postoperative visual improvement was significantly higher among patients treated with PED deployment than in those treated with coiling (p = 0.01). The significant predictors of procedural complications were incomplete occlusion (p = 0.03), hypertension, (p = 0.04), and diabetes (p = 0.03).

CONCLUSIONS

In a large series in which patient outcomes after treatment of paraclinoid aneurysms were compared, the authors found a high rate of aneurysm occlusion and a comparable rate of procedural complications among patients treated with PED placement compared with the rates among those who underwent clipping or coiling. For patients who presented with visual symptoms, those treated with PED placement had the highest rate of visual improvement. The results of this study suggest that the PED is an effective and safe modality for treating paraclinoid aneurysms, especially for patients who present with visual symptoms.

Intraoperative Flash Visual Evoked Potential Recording and Relationship to Visual Outcome

OBJECTIVE

To determine the relationship between intraoperative flash visual evoked potential (FVEP) monitoring and visual function.

METHODS

Intraoperative FVEPs were recorded from electrodes placed in the scalp overlying the visual cortex (Oz) after flashing red light stimulation delivered by Cadwell LED stimulating goggles in 89 patients. Restrictive filtering (typically 10-100 Hz), optimal reject window settings, mastoid reference site, total intravenous anesthetic (TIVA), and stable retinal stimulation (ensured by concomitant electroretinogram [ERG] recording) were used to enhance FVEP reproducibility.

RESULTS

The relationship between FVEP amplitude change and visual outcome was determined from 179 eyes. One eye had a permanent intraoperative FVEP loss despite stable ERG, and this eye had new, severe postoperative visual dysfunction. Seven eyes had transient significant FVEP change (&gt;50% amplitude decrease that recovered by the end of surgery), but only one of those had a decrease in postoperative visual acuity. FVEP changes in all eight eyes (one permanent FVEP loss plus seven transient FVEP changes) were related to surgical manipulation. In each case the surgeon was promptly informed of the FVEP deterioration and took remedial action. The other eyes did not have FVEP changes, and none of those eyes had new postoperative visual deficits.

CONCLUSIONS

Our FVEP findings relate to visual outcome with a sensitivity and specificity of 1.0. New methods for rapidly acquiring reproducible FVEP waveforms allowed for timely reporting of significant FVEP change resulting in prompt surgical action. This may have accounted for the low postoperative visual deficit rate (1%) in this series.

The 25th anniversary of the retrograde suction decompression technique (Dallas technique) for the surgical management of paraclinoid aneurysms: historical background, systematic review, and pooled analysis of the literature

OBJECTIVE

Paraclinoid internal carotid artery (ICA) aneurysms frequently require temporary occlusion to facilitate safe clipping. Brisk retrograde flow through the ophthalmic artery and cavernous ICA branches make simple trapping inadequate to soften the aneurysm. The retrograde suction decompression (RSD), or Dallas RSD, technique was described in 1990 in an attempt to overcome some of those treatment limitations. A frequent criticism of the RSD technique is an allegedly high risk of cervical ICA dissection. An endovascular modification was introduced in 1991 (endovascular RSD) but no studies have compared the 2 RSD variations.

METHODS

The authors performed a systematic review of MEDLINE/PubMed and Web of Science and identified all studies from 1990-2016 in which either Dallas RSD or endovascular RSD was used for treatment of paraclinoid aneurysms. A pooled analysis of the data was completed to identify important demographic and treatment-specific variables. The primary outcome measure was defined as successful aneurysm obliteration. Secondary outcome variables were divided into overall and RSD-specific morbidity and mortality rates.

RESULTS

Twenty-six RSD studies met the inclusion criteria (525 patients, 78.9% female). The mean patient age was 53.5 years. Most aneurysms were unruptured (56.6%) and giant (49%). The most common presentations were subarachnoid hemorrhage (43.6%) and vision changes (25.3%). The aneurysm obliteration rate was 95%. The mean temporary occlusion time was 12.7 minutes. Transient or permanent morbidity was seen in 19.9% of the patients. The RSD-specific complication rate was low (1.3%). The overall mortality rate was 4.2%, with 2 deaths (0.4%) attributable to the RSD technique itself. Good or fair outcome were reported in 90.7% of the patients.Aneurysm obliteration rates were similar in the 2 subgroups (Dallas RSD 94.3%, endovascular RSD 96.3%, p = 0.33). Despite a higher frequency of complex (giant or ruptured) aneurysms, Dallas RSD was associated with lower RSD-related morbidity (0.6% vs 2.9%, p = 0.03), compared with the endovascular RSD subgroup. There was a trend toward higher mortality in the endovascular RSD subgroup (6.4% vs 3.1%, p = 0.08). The proportion of patients with poor neurological outcome at last follow-up was significantly higher in the endovascular RSD group (15.4% vs 7.2%, p < 0.01).

CONCLUSIONS

The treatment of paraclinoid ICA aneurysms using the RSD technique is associated with high aneurysm obliteration rates, good long-term neurological outcome, and low RSD-related morbidity and mortality. Review of the RSD literature showed no evidence of a higher complication rate associated with the Dallas technique compared with similar endovascular methods. On a subgroup analysis of Dallas RSD and endovascular RSD, both groups achieved similar obliteration rates, but a lower RSD-related morbidity was seen in the Dallas technique subgroup. Twenty-five years after its initial publication, RSD remains a useful neurosurgical technique for the management of large and giant paraclinoid aneurysms.

The Superior Hypophyseal Arteries: Anatomical Study with an Endoscopic Endonasal Perspective

BACKGROUND

The use of high-definition endoscopes in extended transsphenoidal approaches to the suprasellar area has significantly improved visualization of its vascularization.

OBJECTIVE

To systematically examine the superior hypophyseal arteries (SHAs) anatomy from an endonasal endoscopic perspective.

METHODS

The endoscopic endonasal transsphenoidal trans-tuberculum approach was performed in 19 adult, fresh and latex injected specimens. Dissections recordings were reviewed to analyze SHAs type, number, and branches, as well as internal carotid arteries (ICA) branches that vascularized optic nerves and chiasm.

RESULTS

Identification of SHAs was possible in all specimens (37/38 sides). The number of SHAs varied from 1 to 3 per side (mean: 1.7). The anterior superior hypophyseal artery was visible in almost all cases (35/37 sides) and originated at the level of the carotid cave in 18/35 specimens; number of branches ranged from 1 to 6 (mean: 3.5), directed to the optic nerve (86%), chiasm (57%), infundibulum (86%), and/or parallel to the pituitary stalk (74%). The 4 main branches and patterns, originally described by McConnell in 1953, were confirmed. The posterior superior hypophyseal artery was evident in 28/37 sides with number of branches ranging from 0 to 4 (mean: 2.1), directed to the optic chiasm (50%), optic tract (32%), infundibulum (79%), and/or pituitary stalk (36%). The surgical implications of this study, together with anatomical and clinical videos, are also briefly discussed.

CONCLUSION

SHAs constitute a complex of anterior and posterior branches that stem from the medial ICA with different patterns, vascularizing the optic apparatus and pituitary stalk.

Anterior clinoidectomy using an extradural and intradural 2-step hybrid technique

In Brief: The authors found a practical intraoperative landmark to localize the optic strut during anterior clinoidectomy and used it as the basis for performing anterior clinoidectomy in two steps: extradural phase and intradural phase. This anatomically based technique can increase the safety of anterior clinoidectomy by providing easily identifiable landmarks and reducing intradural bone drilling, which could put the adjacent neurovauscular structures at risk.