Chronic Oculomotor Nerve Palsy Presentation From Posterior Communicating Artery Aneurysm

Operative Neurosurgery 30:703–710, 2026

This case series analyzes 17 patients with subacute to chronic oculomotor nerve palsy (ONP) caused by posterior communicating artery (PCoA) aneurysms treated between 1991 and 2024. Demographics, aneurysm characteristics, treatment modalities (clipping vs endovascular), and follow-up outcomes are reported, highlighting that only a minority presented with rupture.

The report finds that complete ONP recovery occurred exclusively in patients treated within five weeks of symptom onset, supporting early definitive management to maximize functional nerve recovery despite chronic ONP not reliably predicting imminent aneurysm rupture.

Clinical question: The natural history of chronic oculomotor nerve palsy (ONP) from posterior communicating artery (PCoA) aneurysm is unclear, especially regarding rupture risk and likelihood of nerve recovery when symptoms persist beyond 1 week.

Cohort & design: Case series from a prospectively accrued institutional database (1991–2024) including patients with ≥1 week ONP attributed to PCoA aneurysm; patients with <1 week onset, inadequate follow-up, or other causes of ONP were excluded.

Patient profile: 17 patients; predominantly female (94.1%), median age 56; ONP duration ranged 1 week to 10 years; 29.4% presented with aneurysm rupture.

Treatment approaches: Most were treated with microsurgical clipping (64.7%) or endovascular therapy (29.4%); one patient was managed conservatively due to comorbidities/limited life expectancy.

ONP recovery outcomes: Complete ONP recovery occurred in 23.5% (4/17); all complete recoveries were in patients with symptom duration <5 weeks.

Timing signal: Subacute ONP (<5 weeks) was associated with better recovery (including complete recovery), while chronic ONP (≥5 weeks) had no complete recoveries in this cohort.

Rupture implication: Chronic ONP appeared not to indicate imminent rupture, with only about one-third presenting ruptured and an example of 10 years of stable ONP preceding rupture in the longest-duration case.

Management takeaway: Even if chronic ONP may not predict near-term rupture, early definitive aneurysm treatment is still recommended to maximize the chance of functional ONP recovery.

Role of surgical treatment of intracranial aneurysms in the era of endovascular therapy: a review

Neurosurg Focus 59(6):E2, 2025

This review evaluates the contemporary role of microsurgical clipping versus endovascular treatment (EVT) for intracranial aneurysms, comparing long-term durability, complication profiles, and anatomical or patient factors that guide modality selection. It synthesizes trial data (ISAT, BRAT), meta-analyses, and location-specific outcomes to highlight differences in occlusion, retreatment, and morbidity.

The article also outlines practical considerations—hybrid strategies, cerebral bypass, training needs, economics, and global disparities—arguing for individualized, multidisciplinary decision-making and preserving microsurgical expertise despite growing EVT adoption.

Treatment Goals: Exclusion of intracranial aneurysms from circulation while preserving parent vessels and neural function remains the primary objective; both endovascular treatment (EVT) and microsurgical clipping are core modalities.

Long-term Outcomes: Microsurgical clipping offers greater durability and lower rates of recurrence, rebleeding, and retreatment compared to EVT, which has higher retreatment rates despite lower short-term morbidity.

Procedure Selection: EVT is generally preferred for older patients and posterior circulation aneurysms, while microsurgery is favored in younger patients, those with hematomas, mass effect, and aneurysms of the middle cerebral and pericallosal arteries.

Aneurysm Location: Surgical clipping achieves higher occlusion and lower recurrence, especially for anterior circulation, middle cerebral artery, and complex aneurysms; EVT is more suitable for posterior circulation and anatomically challenging cases.

Complications and Adjuncts: Microsurgery allows for evacuation of hematomas and cisternal blood (reducing vasospasm and hydrocephalus), while EVT avoids craniotomy risks but may induce mechanical vasospasm and requires antiplatelet therapy.

Hybrid and Advanced Techniques: Hybrid approaches (combining EVT and surgery) and cerebral bypass remain essential for complex, giant, or recurrent aneurysms not amenable to standard treatments.

Cost and Access: Microsurgical treatment incurs lower overall healthcare costs than EVT; global disparities exist, with surgical clipping dominating in low-resource settings due to limited endovascular infrastructure.

Decision-Making: Optimal management requires individualized, multidisciplinary evaluation considering patient factors, aneurysm characteristics, and resource availability; no single factor should solely dictate treatment choice

Novel Delivery System Significantly Improves Technical Success and Safety of the Endovascular Clip System (eCLIPs) While Maintaining Efficacy for the Treatment of Wide-Necked Bifurcation Aneurysms

Neurosurgery 97:963–970, 2025

A prospective registry study found that the new eCLIPs electrolytic bifurcation system (eB) for wide-necked bifurcation aneurysms significantly improved technical success and safety over the prior generation, while maintaining high efficacy, with 96% satisfactory occlusion and low rates of neurological complications and retreatment.

• The eCLIPs device is an endovascular implant designed to treat wide-necked bifurcation aneurysms (WNBAs).

• This study compares two generations: the first-generation eCLIPs bifurcation remodeling system (eBRS) and the newer eCLIPs electrolytic bifurcation system (eB).

• A prospective registry included 280 patients; the eB system showed higher implantation success (92% vs 81% for eBRS, P = .007).

• Both systems achieved high rates of satisfactory aneurysm occlusion (mRROC 1+2: 96%).

• The eB system had lower all-cause (1.1%) and neurological (0.5%) death rates compared to eBRS (7% and 5%, respectively).

• Stroke and repeat procedure rates were low for both devices, with eB performing better (stroke: ~1.7%, repeat procedure: 2.2% vs 8.9% for eBRS).

• eCLIPs compares favorably in safety and efficacy to other devices like WEB and stent-assisted coiling.

• The eB system offers improved procedural success and safety, making eCLIPs a strong option for WNBAs; further studies are recommended.

Microsurgical management of 883 previously coiled intracranial aneurysms

J Neurosurg 143:654–667, 2025

This systematic review and meta-analysis found that microsurgical management of previously coiled intracranial aneurysms is effective and safe in well-selected patients, achieving high complete occlusion and good functional outcomes, especially with delayed direct clipping, small aneurysm size, and anterior location.

• Microsurgical management of previously coiled intracranial aneurysms (IAs) is effective and safe in well-selected patients.

• Meta-analysis included 874 patients with 883 previously coiled IAs; most underwent direct clipping.

• Complete occlusion rate was 97.2%, good functional outcome 82.9%, and perioperative mortality 3.7%.

• Direct clipping had the best safety and efficacy, with the lowest rates of complications and highest rates of good outcomes.

• Smaller, anteriorly located, and unruptured aneurysms were associated with the most favorable outcomes.

• Early microsurgery (within 1 month of coiling) and Gurian group C IAs had higher perioperative death rates.

• Key management factors: IA size, location, rupture status, indication, and timing/type of microsurgery.

• Most studies were retrospective case series, limiting subgroup analysis and introducing some heterogeneity.

Open Microsurgical Versus Endovascular Management of Unruptured and Ruptured Brain Aneurysms

Operative Neurosurgery 29:171–180, 2025

This review compares open microsurgical clipping and endovascular techniques for treating unruptured and ruptured brain aneurysms, discussing their respective risks, benefits, and outcomes. It emphasizes individualized treatment decisions based on aneurysm characteristics, patient factors, and advances in both surgical and endovascular modalities.

• Microsurgical clipping and endovascular techniques are the main treatments for intracranial aneurysms, each with distinct risks and benefits.

• Clipping offers more durable repairs and lower retreatment rates but is more invasive and has higher short-term morbidity, especially in ruptured aneurysms.

• Endovascular treatments (coiling, stenting, flow diverters) are less invasive, have shorter recovery, and are preferred for older patients or those with comorbidities, but have higher recurrence and retreatment rates.

• Aneurysm characteristics such as size, location, morphology, and patient age/comorbidities are critical in selecting the optimal treatment.

• Posterior circulation aneurysms and wide-necked or complex aneurysms often favor endovascular approaches due to surgical risks.

• Clipping is particularly advantageous for younger patients, anterior circulation, and when hematoma evacuation or fenestration is needed.

• New endovascular devices (flow diverters, WEB) expand treatment options but require further study for long-term outcomes.

• Treatment decisions should be individualized, ideally at centers with expertise in both techniques, considering rupture status, anatomy, and patient factors.

From conservative to interventional management in unruptured intracranial aneurysms

J Neurosurg 142:619–625, 2025

Study Focus: Management of unruptured intracranial aneurysms (UIAs) from conservative to interventional.

Objective: Identify patterns and predictors for revising UIA management strategy.

Methodology: Retrospective review of cases diagnosed between 2006-2022 with conservative management.

Results: 10 of 144 cases shifted to interventional treatment due to aneurysm growth.

UIA Growth: Most frequent reason for changing treatment strategy.

Size Threshold: UIAs > 3 mm at diagnosis more likely to require intervention.

Conservative Management: Regular radiographic follow-ups recommended, especially for UIAs > 3 mm.

Guidelines: ESO and American Heart Association guidelines emphasize monitoring UIA growth.

Statistical Analysis: Cox regression and Kaplan-Meier curves used for data analysis.

Risk Factors: No significant effect of potential risk factors on treatment change.

Imaging: DSA as confirmative modality for revising conservative management.

Study Limitations: Low statistical power due to limited cases of treatment change.

Conclusion: Regular monitoring crucial for conservatively managed UIAs, especially > 3 mm.

The impact of regular aspirin use on aneurysm recanalization rates after endovascular coiling

J Neurosurg 141:1020–1025, 2024

Intracranial aneurysms (IAs) pose a significant health risk, often leading to subarachnoid hemorrhage and severe neurological outcomes. Endovascular coiling has been a principal treatment method, but it comes with the challenge of high recanalization rates. Aspirin has recently emerged as a potential agent to reduce these rates. In this study, the authors aimed to investigate the impact of regular aspirin use on aneurysm recanalization rates following endovascular coiling in a 10-year single-institution study.

METHODS A retrospective analysis was conducted on a dataset of 2236 aneurysms treated by a single neurosurgeon over a period of 10 years. The primary outcome measure was aneurysm recanalization, defined by a change in the Raymond-Roy Occlusion Classification of at least one grade.

RESULTS A total of 525 aneurysms were coiled, 109 of which involved patients who reported regular use of aspirin. The recanalization rate was significantly lower in the aspirin group (9.2%) compared with the control group (23.6%) (OR 0.33, 95% CI 0.15–0.66; p = 0.001). On analysis of the specific mechanisms of recanalization, aneurysm sac growth was less frequent in the aspirin group (5.5%) compared with the control group (18%) (OR 0.265, 95% CI 0.09–0.63; p = 0.002). Additionally, patients in the control group had a higher retreatment rate (18%) than patients in the aspirin group (5.5%) (OR 0.265, 95% CI 0.09–0.63; p = 0.002).

CONCLUSIONS Regular use of aspirin appears to be associated with reduced rates of aneurysm recanalization after endovascular coiling. However, caution is advised in interpretation of these results given the retrospective nature of this study. Further randomized controlled trials are needed to confirm these findings.

Delayed coil migration into oropharynx following endovascular coiling of a traumatic carotid cavernous fistula

Acta Neurochirurgica (2022) 164:1287–1292

Carotid-cavernous fistulas (CCFs) are abnormal vascular shunts between the carotid artery and the cavernous sinus.

A 37-year-old male presented with a traumatic CCF and basal skull fracture extending through the medial wall of the cavernous sinus and sphenoid sinus. The CCF was treated with endovascular coiling.

Three months after this procedure, he was found to have coil migration through the traumatic sphenoid defect into the pharynx. He underwent urgent endonasal endoscopic surgery to disconnect and remove the extruded coil.

Post-operative coil migration is a rare but serious complication following endovascular treatment of traumatic CCF.

Safety, Efficacy, and Durability of Stent Plus Balloon-Assisted Coiling for the Treatment of Wide-Necked Intracranial Bifurcation Aneurysms

Neurosurgery 88:1028–1037, 2021

Wide-necked bifurcation aneurysms remain a challenge for endovascular surgeons. Dual-stent-assisted coiling techniques have been defined to treat bifurcation aneurysms with a complex neck morphology. However, there are still concerns about the safety of dual-stenting procedures. Stent plus balloon-assisted coiling is a recently described endovascular technique that enables the coiling of wide-necked complex bifurcation aneurysms by implanting only a single stent.

OBJECTIVE: To investigate the feasibility, efficacy, safety, and durability of this technique for the treatment of wide-necked bifurcation aneurysms.

METHODS: A retrospective review was performed of patients with wide-necked intracranial bifurcation aneurysms treated with stent plus balloon-assisted coiling. The initial and follow-up clinical and angiographic outcomeswere assessed. Preprocedural and follow-up clinical statuses were assessed using modified Rankin scale.

RESULTS: A total of 61 patients (mean age: 54.6 ± 10.4 yr) were included in the study. The immediate postprocedural digital subtraction angiography revealed complete aneurysm occlusion in 86.9% of the cases. A periprocedural complication developed in 11.5% of the cases. We observed a delayed ischemic complication in 4.9%. There was no mortality in this study. The permanent morbidity rate was 3.3%. The follow-up angiography was performed in 55 of 61 patients (90.1%) (the mean follow-up period was 25.5 ± 27.3 mo). The rate of complete aneurysm occlusion at the final angiographic follow-up was 89.1%. The retreatment rate was 1.8%.

CONCLUSION: The results of this study showed that stent plus balloon-assisted coiling is a feasible, effective, and relatively safe endovascular technique for the treatment of widenecked bifurcation aneurysms located in the posterior and anterior circulation.

Stent PlusBalloon-Assisted Coiling for the Treatment ofWide-Necked Intracranial Bifurcation Aneurysms

Neurosurgery 88:1028–1037, 2021

Wide-necked bifurcation aneurysms remain a challenge for endovascular surgeons. Dual-stent-assisted coiling techniques have been defined to treat bifurcation aneurysms with a complex neck morphology. However, there are still concerns about the safety of dual-stenting procedures. Stent plus balloon-assisted coiling is a recently described endovascular technique that enables the coiling of wide-necked complex bifurcation aneurysms by implanting only a single stent.

OBJECTIVE:To investigate the feasibility, efficacy, safety, and durability of this technique for the treatment of wide-necked bifurcation aneurysms.

METHODS:A retrospective review was performed of patients with wide-necked intracranial bifurcation aneurysms treated with stent plus balloon-assisted coiling. The initial and follow-up clinical and angiographic outcomes were assessed. Preprocedural and follow-up clinical statuses were assessed using modified Rankin scale.

RESULTS:A total of 61 patients (mean age: 54.6±10.4 yr) were included in the study. The immediate postprocedural digital subtraction angiography revealed complete aneurysm occlusion in 86.9% of the cases. A periprocedural complication developed in 11.5% of the cases. We observed a delayed ischemic complication in 4.9%. There was no mortality in this study. The permanent morbidity rate was 3.3%. The follow-up angiography was performed in 55 of 61 patients (90.1%) (the mean follow-up period was 25.5±27.3 mo).The rate of complete aneurysm occlusion at the final angiographic follow-up was 89.1%. The retreatment rate was 1.8%.

CONCLUSION:The results of this study showed that stent plus balloon-assisted coiling is a feasible, effective, and relatively safe endovascular technique for the treatment of wide-necked bifurcation aneurysms located in the posterior and anterior circulation.

 

Early postmarket results with PulseRider for treatment of wide-necked intracranial aneurysms: a multicenter experience

J Neurosurg 133:1756–1765, 2020

Traditionally, stent-assisted coiling and balloon remodeling have been the primary endovascular treatments for wide-necked intracranial aneurysms with complex morphologies. PulseRider is an aneurysm neck reconstruction device that provides parent vessel protection for aneurysm coiling. The objective of this study was to report early postmarket results with the PulseRider device.

METHODS This study was a prospective registry of patients treated with PulseRider at 13 American neurointerventional centers following FDA approval of this device. Data collected included clinical presentation, aneurysm characteristics, treatment details, and perioperative events. Follow-up data included degree of aneurysm occlusion and delayed (> 30 days after the procedure) complications.

RESULTS A total of 54 aneurysms were treated, with the same number of PulseRider devices, across 13 centers. Fourteen cases were in off-label locations (7 anterior communicating artery, 6 middle cerebral artery, and 1 A1 segment anterior cerebral artery aneurysms). The average dome/neck ratio was 1.2. Technical success was achieved in 52 cases (96.2%). Major complications included the following: 3 procedure-related posterior cerebral artery strokes, a devicerelated intraoperative aneurysm rupture, and a delayed device thrombosis. Immediately postoperative Raymond-Roy occlusion classification (RROC) class 1 was achieved in 21 cases (40.3%), class 2 in 15 (28.8%), and class 3 in 16 cases (30.7%). Additional devices were used in 3 aneurysms. For those patients with 3- or 6-month angiographic follow-up (28 patients), 18 aneurysms (64.2%) were RROC class 1 and 8 (28.5%) were RROC class 2.

CONCLUSIONS PulseRider is being used in both on- and off-label cases following FDA approval. The clinical and radiographic outcomes are comparable in real-world experience to the outcomes observed in earlier studies. Further experience is needed with the device to determine its role in the neurointerventionalist’s armamentarium, especially with regard to its off-label use.

PulseRider for treatment of wide-necked intracranial aneurysms: a multicenter experience

J Neurosurg 133:1756–1765, 2020

Traditionally, stent-assisted coiling and balloon remodeling have been the primary endovascular treatments for wide-necked intracranial aneurysms with complex morphologies. PulseRider is an aneurysm neck reconstruction device that provides parent vessel protection for aneurysm coiling. The objective of this study was to report early postmarket results with the PulseRider device.

METHODS This study was a prospective registry of patients treated with PulseRider at 13 American neurointerventional centers following FDA approval of this device. Data collected included clinical presentation, aneurysm characteristics, treatment details, and perioperative events. Follow-up data included degree of aneurysm occlusion and delayed (> 30 days after the procedure) complications.

RESULTS A total of 54 aneurysms were treated, with the same number of PulseRider devices, across 13 centers. Fourteen cases were in off-label locations (7 anterior communicating artery, 6 middle cerebral artery, and 1 A1 segment anterior cerebral artery aneurysms). The average dome/neck ratio was 1.2. Technical success was achieved in 52 cases (96.2%). Major complications included the following: 3 procedure-related posterior cerebral artery strokes, a devicerelated intraoperative aneurysm rupture, and a delayed device thrombosis. Immediately postoperative Raymond-Roy occlusion classification (RROC) class 1 was achieved in 21 cases (40.3%), class 2 in 15 (28.8%), and class 3 in 16 cases (30.7%). Additional devices were used in 3 aneurysms. For those patients with 3- or 6-month angiographic follow-up (28 patients), 18 aneurysms (64.2%) were RROC class 1 and 8 (28.5%) were RROC class 2.

CONCLUSIONS PulseRider is being used in both on- and off-label cases following FDA approval. The clinical and radiographic outcomes are comparable in real-world experience to the outcomes observed in earlier studies. Further experience is needed with the device to determine its role in the neurointerventionalist’s armamentarium, especially with regard to its off-label use.

Is 3 years adequate for tracking completely occluded coiled aneurysms?

J Neurosurg 133:758–764, 2020

The authors conducted a study to ascertain the long-term durability of coiled aneurysms completely occluded at 36 months’ follow-up given the potential for delayed recanalization.

METHODS In this retrospective review, the authors examined 299 patients with 339 aneurysms, all shown to be completely occluded at 36 months on follow-up images obtained between 2011 and 2013. Medical records and radiological data acquired during the extended monitoring period (mean 74.3 ± 22.5 months) were retrieved, and the authors analyzed the incidence of (including mean annual risk) and risk factors for delayed recanalization.

RESULTS A total of 5 coiled aneurysms (1.5%) occluded completely at 36 months showed recanalization (0.46% per aneurysm-year) during the long-term surveillance period (1081.9 aneurysm-years), 2 surfacing within 60 months and 3 developing thereafter. Four showed minor recanalization, with only one instance of major recanalization. The latter involved the posterior communicating artery as an apparent de novo lesion, arising at the neck of a firmly coiled sac, and was unrelated to coil compaction or growth. Additional embolization was undertaken. In a multivariate analysis, a second embolization for a recurrent aneurysm (HR = 22.088, p = 0.003) independently correlated with delayed recanalization.

CONCLUSIONS Almost all coiled aneurysms (98.5%) showing complete occlusion at 36 months postembolization proved to be stable during extended observation. However, recurrent aneurysms were predisposed to delayed recanalization. Given the low probability yet seriousness of delayed recanalization and the possibility of de novo aneurysm formation, careful monitoring may be still considered in this setting but at less frequent intervals beyond 36 months.

Outcomes of Retreatment for Intracranial Aneurysms—A Meta-Analysis

Neurosurgery. 2019 Dec 1;85(6):750-761

Long-term results from the International Subarachnoid Hemorrhage Trial (ISAT) and Barrow Ruptured Aneurysm Trial (BRAT) indicate considerably higher retreatment rates for aneurysms treated with coiling compared to clipping, but do not report the outcome of retreatment.

OBJECTIVE: To evaluate retreatment related outcomes.

METHODS: A meta-analysis in accordance with PRISMA guidelines was conducted using Medline search engines PubMed and EMBASE to identify articles describing outcomes after retreatment for intracranial aneurysms. Pooled prevalence rates for complete occlusion rate and mortality were calculated. Outcomes of different treatment and retreatment combinations were not compared because of indication bias.

RESULTS: Twenty-five articles that met the inclusion criteria were included in the metaanalysis. Surgery after coiling had a pooled complete occlusion rate of 91.2% (95% confidence interval [CI]: 87.0-94.1) and a pooled mortality rate of 5.6% (95% CI: 3.7-8.3). Coiling after coiling had a pooled complete occlusion rate of 51.3% (95% CI: 22.1-78.0) and a pooled mortality rate of 0.8% (95% CI: 0.15-3.7). Surgery after surgery did not provide a pooled estimate for complete occlusion as only one study was identified but had a pooled mortality rate of 5.9% (95% CI: 3.1-11.2). Coiling after surgery had a pooled complete occlusion rate of 56.1% (95% CI: 11.4-92.7) and a pooled mortality rate of 9.3% (95% CI: 4.1- 19.9). All pooled incidence rates were produced using random-effect models.

CONCLUSION: Surgical retreatment was associated with a high complete occlusion rate but considerable mortality. Conversely, endovascular retreatment was associated with low mortality but also a low complete occlusion rate.

Management of recurrent intracranial aneurysms after coil embolization: a novel classification scheme based on angiography

J Neurosurg 131:1455–1461, 2019

Recurrent aneurysms after coil embolization remain a challenging issue. The goal of the present study was to report the authors’ experience with recurrent aneurysms after coil embolization and to discuss the radiographic classification scheme and recommended management strategy.

METHODS Aneurysm treatments from a single institution over a 6-year period were retrospectively reviewed. Ninetyseven aneurysms that recurred after initial coiling were managed during the study period. Recurrent aneurysms were classified into the following 5 types based on their angiographic characteristics: I, pure recanalization inside the aneurysm sac; II, pure coil compaction without aneurysm growth; III, new aneurysm neck formed without coil compaction; IV, new aneurysm neck formed with coil compaction; and V, newly formed aneurysm neck and sac.

RESULTS Aneurysm recurrences resulted in rehemorrhages in 6 cases (6.2%) of type III–V aneurysms, but in none of type I–II aneurysms. There was a significantly higher proportion of ophthalmic artery aneurysms and complex internal carotid artery aneurysms presenting as types I and II than presented as the other 3 types (63.3% vs 16.4%, p < 0.001). In contrast, for posterior communicating artery aneurysms and anterior communicating artery aneurysms, a higher proportion of type III–V aneurysms was observed than for the other 2 types, but without a significant difference in the multivariate model (56.7% vs 23.3%). In addition, giant (> 25 mm) aneurysms were more common among type I and II lesions than among type III and IV aneurysms (36.7% vs 9.0%, p = 0.001), which exhibited a higher proportion of small (< 10 mm) lesions (65.7% vs 13.3%, p < 0.001). A single reembolization procedure was sufficient to occlude 80.0% of type I recurrences and 83.3% of type II recurrences from coil compaction but only 65.6% of type III–V recurrences from aneurysm regrowth.

CONCLUSIONS Aneurysm size and location represent the determining factors of the angiographic recurrence types. Type I and II recurrences were safely treated by reembolization, whereas type III–V recurrences may be best managed surgically when technically feasible.

Neck Remnants and the Risk of Aneurysm Rupture After Endovascular TreatmentWith Coiling or Stent-Assisted Coiling

Neurosurgery 84:421–427, 2019

Neck remnants are not uncommon after endovascular treatment of cerebral aneurysms. Critics of endovascular treatments for cerebral aneurysms cite neck remnants as evidence in favor of microsurgical clipping. However, studies have failed to evaluate the true clinical significance of aneurysm neck remnants following endovascular therapies.

OBJECTIVE: To assess the clinical significance of residual aneurysm necks and to determine the rate of subsequent rupture following coiling or stent-assisted coiling of cerebral aneurysms.

METHODS: We retrospectively reviewed the records of 1292 aneurysm cases that underwent endovascular treatment at 4 institutions. Aneurysms treated by primary coiling or stent-assisted coiling were included in the study; those treated by flow diversion were excluded Aneurysms with residual filling (i.e., Raymond–Roy Occlusion Classification II, neck remnant; or III, residual aneurysm filling) were assessed for their risk of subsequent rupture.

RESULTS: A total of 626 aneurysms were identified as having residual filling immediately posttreatment. Of these, 13 aneurysms (2.1%) ruptured during the follow-up period (mean 7.3 mo; range 1-84 mo). Eleven of the 13 (84.6%) were ruptured at presentation. Rupture at presentation, the size of the aneurysm, and the increasing age of the patient were predictive of posttreatment rupture.

CONCLUSION: We found that unruptured aneurysms with residual necks following endovascular treatment posed a very low risk of rupture (0.6%). However, patients presenting with ruptured aneurysms had a higher risk of rerupture from a neck remnant (3.4%). These results highlight the importance of achieving complete angiographic occlusion of ruptured aneurysms.

Coiling Versus Microsurgical Clipping in the Treatment of Unruptured Middle Cerebral Artery Aneurysms: A Meta-Analysis

Neurosurgery 83:879–889, 2018

Open microsurgical clipping of unruptured intracranial aneurysms has long been the gold standard, yet advancements in endovascular coiling techniques have begun to challenge the status quo. OBJECTIVE: To compare endovascular coiling with microsurgical clipping among adults with unruptured middle cerebral artery aneurysms (MCAA) by conducting a meta-analysis.

METHODS: A systematic search was conducted from January 2011 to October 2015 to update a previous meta-analysis. All studies that reported unruptured MCAA in adults treated by microsurgical clipping or endovascular coiling were included and cumulatively analyzed.

RESULTS: Thirty-seven studies including 3352 patients were included. Using the randomeffects model, pooled analysis of 11 studies of microsurgical clipping (626 aneurysms) revealed complete aneurysmal obliteration in 94.2% of cases (95% confidence interval [CI] 87.6%-97.4%). The analysis of 18 studies of endovascular coiling (759 aneurysms) revealed complete obliteration in 53.2% of cases (95% CI: 45.0%-61.1%). Among clipping studies, 22 assessed neurological outcomes (2404 aneurysms), with favorable outcomes in 97.9% (95% CI: 96.8%-98.6%). Among coiling studies, 22 examined neurological outcomes (826 aneurysms), with favorable outcomes in 95.1% (95% CI: 93.1%-96.5%). Results using the fixed-effect models were not materially different.

CONCLUSION: This updated meta-analysis demonstrates that surgical clipping for unruptured MCAA remains highly safe and efficacious. Endovascular treatment for unruptured MCAAs continues to improve in efficacy and safety; yet, it results in lower rates of occlusion.

 

Early diffusion-weighted MRI lesions after treatment of unruptured intracranial aneurysms:

J Neurosurg 126:1070–1078, 2017

Diffusion-weighted MRI was used to assess periprocedural lesion load after repair of unruptured intracranial aneurysms (UIA) by microsurgical clipping (MC) and endovascular coiling (EC).

METHODS Patients with UIA were assigned to undergo MC or EC according to interdisciplinary consensus and underwent diffusion-weighted imaging (DWI) 1 day before and 1 day after aneurysm treatment. Newly detected lesions by DWI after treatment were the primary end point of this prospective study. Lesions detected by DWI were categorized as follows: A) 1–3 DWI spots < 10 mm, B) > 3 DWI spots < 10 mm, C) single DWI lesion > 10 mm, or D) DWI lesion related to surgical access.

RESULTS Between 2010 and 2014, 99 cases were included. Sixty-two UIA were treated by MC and 37 by EC. There were no significant differences between groups in age, sex, aneurysm size, occurrence of multiple aneurysms in 1 patient, or presence of lesions detected by DWI before treatment. Aneurysms treated by EC were significantly more often located in the posterior circulation (p < 0.001). Diffusion-weighted MRI detected new lesions in 27 (43.5%) and 20 (54.1%) patients after MC and EC, respectively (not significant). The pattern of lesions detected by DWI varied significantly between groups (p < 0.001). Microembolic lesions (A and B) found on DWI were detected more frequently after EC (A, 14 cases; B, 5 cases) than after MC (A, 5 cases), whereas C and D were rare after EC (C, 1 case) and occurred more often after MC (C, 12 cases and D, 10 cases). No procedure-related unfavorable outcomes were detected.

CONCLUSIONS According to the specific techniques, lesion patterns differ between MC and EC, whereas the frequency of new lesions found on DWI is similar after occlusion of UIA. In general, the lesion load was low in both groups, and lesions were clinically silent. Clinical trial registration no.: NCT01490463 (clinicaltrials.gov)

Comparison of clipping and coiling in elderly patients with unruptured cerebral aneurysms

J Neurosurg 126:811–818, 2017

The comparative effectiveness of the 2 treatment options—surgical clipping and endovascular coiling—for unruptured cerebral aneurysms remains an issue of debate and has not been studied in clinical trials. The authors investigated the association between treatment method for unruptured cerebral aneurysms and outcomes in elderly patients.

METHODS The authors performed a cohort study of 100% of Medicare fee-for-service claims data for elderly patients who had treatment for unruptured cerebral aneurysms between 2007 and 2012. To control for measured confounding, the authors used propensity score conditioning and inverse probability weighting with mixed effects to account for clus- tering at the level of the hospital referral region (HRR). An instrumental variable (regional rates of coiling) analysis was used to control for unmeasured confounding and to create pseudo-randomization on the treatment method.

RESULTS During the study period, 8705 patients underwent treatment for unruptured cerebral aneurysms and met the study inclusion criteria. Of these patients, 2585 (29.7%) had surgical clipping and 6120 (70.3%) had endovascular coiling. Instrumental variable analysis demonstrated no difference between coiling and clipping in 1-year postoperative mortality (OR 1.25, 95% CI 0.68–2.31) or 90-day readmission rate (OR 1.04, 95% CI 0.66–1.62). However, clipping was associ- ated with a greater likelihood of discharge to rehabilitation (OR 6.39, 95% CI 3.85–10.59) and 3.6 days longer length of stay (LOS; 95% CI 2.90–4.71). The same associations were present in propensity score–adjusted and inverse probability–weighted models.

CONCLUSIONS In a cohort of Medicare patients, there was no difference in mortality and the readmission rate between clipping and coiling of unruptured cerebral aneurysms. Clipping was associated with a higher rate of discharge to a rehabilitation facility and a longer LOS.

A new comorbidities index for risk stratification for treatment of unruptured cerebral aneurysms

Aneurysm surgery

J Neurosurg 125:713–719, 2016

Comorbidities have an impact on risk stratification for outcomes in analyses of large patient databases. Although the Charlson Comorbidity Index (CCI) and the Elixhauser Comorbidity Index (ECI) are the most commonly used comorbidity indexes, these have not been validated for patients with unruptured cerebral aneurysms; therefore, the authors created a comorbidity index specific to these patients.

Methods The authors extracted all records involving unruptured cerebral aneurysms treated with clipping, coiling, or both from the Nationwide Inpatient Sample (2002–2010). They assessed the effect of 37 variables on poor outcome and used the results to create a risk score for these patients. The authors used a validation data set and bootstrapping to evaluate the new index and compared it to CCI and ECI in prediction of poor outcome, mortality, length of stay, and hospital charges.

Results The index assigns integer values (-2 to 7) to 20 comorbidities: neurological disorder, renal insufficiency, gastrointestinal bleeding, paralysis, acute myocardial infarction, electrolyte disorder, weight loss, metastatic cancer, drug abuse, arrhythmia, coagulopathy, cerebrovascular accident, psychosis, alcoholism, perivascular disease, valvular disease, tobacco use, hypothyroidism, depression, and hypercholesterolemia. Values are summed to determine a patient’s risk score. The new index was better at predicting poor outcome than CCI or ECI (area under the receiver operating characteristic curve [AUC] 0.814 [95% CI 0.798–0.830], vs 0.694 and 0.712, respectively, for the other indices), and it was also better at predicting mortality (AUC 0.775 [95% CI 0.754–0.792], vs 0.635 and 0.657, respectively, for CCI and ECI).

Conclusions This new comorbidity index outperforms the CCI and ECI in predicting poor outcome, mortality, length of stay, and total charges for patients with unruptured cerebral aneurysm. Reevaluation of other patient cohorts is warranted to determine the impact of more accurate patient stratification.