Basilar artery perforator rupture as the cause of perimesencephalic subarachnoid hemorrhage

J Neurosurg 144:1271–1277, 2026

This clinical study evaluates the etiology of perimesencephalic subarachnoid hemorrhage (pmSAH) by applying high-resolution cone-beam CT (CBCT) during catheter angiography to detect basilar artery perforator outpouchings. The retrospective analysis of 22 pmSAH patients found that CBCT identified basilar perforator pseudoaneurysms in a substantial subset, with conservative management yielding excellent outcomes.

The authors argue that many pmSAHs may be arterial rather than venous in origin when imaged with modern high-resolution CBCT protocols. They recommend heightened suspicion for an arterial source and detailed angiographic CBCT acquisition, while acknowledging limits of retrospective design, variable imaging quality, and unresolved management questions.

Objective High-resolution CBCT performed during catheter angiography was used to better identify the etiology of perimesencephalic SAH (pmSAH), challenging the historical assumption of a venous source.

Methods Retrospective review of pmSAH cases (Jan 2023–Dec 2024) requiring catheter angiography with available, diagnostic-quality CBCT; images were interpreted by two experienced neuroangiographers to consensus.

Cohort Of 152 spontaneous SAH presentations, 22 met Rinkel criteria for pmSAH; after exclusions (alternative causes found, missing/low-quality CBCT), 13 patients remained for CBCT-based imaging analysis.

Key finding In 8/13 (61.5%) analyzed pmSAH cases, CBCT showed a basilar artery perforator focal outpouching consistent with a rupture site (submillimeter, 0.4–0.8 mm).

Anatomy distribution Among the 8 identified perforator lesions, 6 were rostral basilar perforators, with 1 midbasilar and 1 caudal perforator involvement.

Outcomes All pmSAH patients—including those with identified basilar perforator outpouchings—had excellent recovery, with no re-rupture events and no clinically significant vasospasm reported in the series.

Follow-up imaging In patients who underwent follow-up DSA with CBCT, the basilar perforator finding resolved on follow-up imaging.

Conclusion/implication pmSAH should be approached with high suspicion for an arterial etiology (basilar perforator pseudoaneurysm frequently detectable with high-resolution CBCT), and conservative management was associated with excellent outcomes in this cohort.

Neuropsychological profile and risk factors for poor cognitive outcomes in survivors of aneurysmal subarachnoid hemorrhage

J Neurosurg 144:517–525, 2026

This clinical study characterizes long-term neuropsychological outcomes in 156 survivors of aneurysmal subarachnoid hemorrhage (aSAH), using MoCA-22, digit span, and verbal fluency tests. Findings show that 34% scored below the 25th percentile despite largely favorable functional recovery, with deficits concentrated in executive function, working memory, and language.

Multivariable analysis identified modified Fisher grade 4 on admission and new radiological infarction during hospitalization as independent predictors of poor cognitive outcomes. Secondary assessments revealed frequent depressive symptoms and acquired personality disturbances, implicating impacts on work productivity and social relationships.

Objective Characterize neuropsychological deficits in aneurysmal subarachnoid hemorrhage (aSAH) survivors and identify clinical variables linked to poor cognitive outcomes.

Design/assessments Retrospective cohort (2009–2024) with cognitive testing ≥6 months post-aSAH using MoCA-22, Digit Span Forward/Backward, and Verbal Fluency; poor outcome defined as MoCA-22 <25th percentile (norm-adjusted).

Prevalence 34% (53/156) had MoCA-22 <25th percentile despite most having good functional recovery at discharge (mRS ≤2 in 79% of those with poor MoCA-22).

Cognitive profile Moderate/severe deficits (z-score >1 SD below norms) occurred in 11% on DST-F, 27% on DST-B, and 9% on VFT, highlighting prominent working-memory/executive-function vulnerability.

Key risk factors Modified Fisher grade 4 on admission and new radiological infarction during hospitalization were independently associated with poor MoCA-22 outcomes (aOR 2.43 and 2.71, respectively).

Quality of life impact Radiological infarction was associated with worse work productivity (OR 0.69) and social relationships (OR 0.72).

Behavioral sequelae Among those assessed, 27% reported at least mild depressive symptoms and 64% showed acquired personality disturbance.

Bottom line Cognitive/behavioral deficits can persist long after aSAH even with favorable mRS; higher hemorrhage burden (modified Fisher 4) and in-hospital infarction signal higher risk.

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.

Anterior choroidal artery aneurysms: a systematic review and meta-analysis of outcomes and ischemic complications following surgical and endovascular treatment

J Neurosurg 142:127–137, 2025

Anterior choroidal artery (AChA) aneurysms account for 2%–5% of all intracranial aneurysms. Treatment considerations include microsurgical clipping, flow diversion, or coiling with or without adjunctive devices. AChA aneurysms pose challenges in treatment due to the origination of the aneurysm from the origin or proximal segment of the AChA. The AChA is particularly susceptible to vasospasm and occlusion during treatment with devastating neurological deficits, including hemiparesis, hemianesthesia, lethargy, neglect, and hemianopia. In this study, the authors performed a meta-analysis to quantify the outcomes and complication rates across treatment modalities for AChA aneurysms and to identify risk factors reported in the literature.

METHODS The authors performed a systematic review of AChA aneurysms treated with surgical clipping, endovascular coiling, or flow diversion and reported in the PubMed, Embase, Scopus, and Cochrane search databases. Single-arm meta-analyses of the selected outcomes were performed in RStudio.

RESULTS Literature review yielded 25 studies that met the inclusion criteria. In total, 1627 patients were included in the analysis, with 554 males, 1009 females, and 64 unspecified. The rate of any complication in the full cohort was 11.6%, with a rate of ischemic complications of 5.5% and a favorable recovery rate of 90.3% of all patients treated. In total, 1064 patients underwent surgical clipping, 443 were treated with coiling, and 120 patients with flow diversion. In clipped patients, the rate of total surgical complications was 17.6%, with an ischemic complication rate of 9.4%. The rate of good functional recovery, defined on the basis of a Glasgow Outcome Scale score of 4–5 or modified Rankin Scale score of 0–2, was 88.0%, and complete obliteration was achieved in 84.5% of surgically clipped aneurysms. The complication rate in coiled patients was 10.3%, with an ischemic complication rate of 3.0%. Good functional recovery was achieved in 88.6% of coiled patients and complete aneurysm obliteration in 74.1%. Flow diversion resulted in a complication rate of 1.3%, with 0.7% rate of ischemic complications. Good functional recovery was achieved in 98.4% of patients and complete aneurysm obliteration in 79.0% in the flow diversion group. Aneurysm morphological features that impacted the complication rate were also identified to augment quantitative data and to help guide treatment selection for AChA aneurysms.

CONCLUSIONS Flow diversion showed significantly lower total and ischemic complications and improved outcomes compared to clipping and coiling. There may be differences in outcomes between treatment types, especially when considering the varied patient presentations that guide treatment selection.

Comparing surgical clipping with endovascular treatment for unruptured middle cerebral artery aneurysms: a systematic review and updated meta-analysis

J Neurosurg 142:116–126, 2025

Unruptured middle cerebral artery aneurysm (uMCAA) has traditionally been treated with open surgical clipping (SC). Endovascular treatments (EVTs) were designed to reduce surgical risks in these cases. Nevertheless, despite its potential benefits, many surgeons favor SC for uMCAA. This updated meta-analysis aimed to compare the safety, efficacy, and clinical outcomes of SC and EVT for uMCAA.

METHODS The authors searched the Medline, Embase, and Cochrane Library databases according to the Cochrane and PRISMA guidelines. Eligible studies included those with ≥ 4 patients with uMCAA reporting comparative data of SC and EVT. The endpoints were the complete occlusion rate (Raymond class I and II), good clinical outcomes (modified Rankin Scale score ≤ 2 or Glasgow Outcome Scale score ≥ 4), procedure-related complications (further divided into major and minor), and mortality. The authors pooled OR with 95% CI values with a random-effects model. I 2 statistics were used to assess heterogeneity, and sensitivity analysis was conducted to address high heterogeneity. Publication bias was assessed with funnel plot analysis and the Egger’s test.

RESULTS The analysis included data from 10 studies. Regarding the complete occlusion assessment, the comparative analysis revealed OR 0.17 (95% CI 0.08–0.40, p < 0.01), favoring SC. In terms of achieving good clinical outcomes, OR 0.44 (95% CI 0.20–0.97, p < 0.05) was determined, favoring SC. No differences regarding total procedure-related complications, major complications, or mortality were identified. However, a higher likelihood of minor complications was identified for EVT, with OR 4.68 (95% CI 2.01–10.92, p < 0.01).

CONCLUSIONS This systematic review and meta-analysis identified a lower likelihood of complete occlusion at last follow-up and lower likelihood of good clinical outcomes in patients treated with EVT when compared with SC. Furthermore, a higher likelihood of minor complications was identified in patients who underwent EVT when compared with SC. The findings reinforce that, based on the currently available data, SC should be considered the primary approach for treating uMCAA. However, EVT is an evolving approach, and this study’s findings represent a synthesis of observational studies. Randomized trials are warranted to elucidate which approach should be the mainstay for uMCAA and to identify the nuances that determine whether SC or EVT is more or less indicated for addressing uMCAA with consideration of the individuality of each patient and aneurysm.

Microsurgical management of recurrent intracranial aneurysm after endovascular treatment: a series of 60 consecutive patients

J Neurosurg 141:1235–1243, 2024

The aim of this study was to evaluate the morbidity associated with microsurgical treatment in patients with a recurrent aneurysm to improve their surgical management.

METHODS From 2012 to 2022, among the 3128 patients with ruptured or unruptured intracranial aneurysms managed at the authors’ institution, 954 patients were treated by a microsurgical procedure. Of these 3128 patients, 60 consecutive patients (6.3%) who had a recurrent microsurgically treated aneurysm after previous endovascular treatment were included in this study. Additional microsurgical treatment was considered in case of progressive remnant growth or significant aneurysm recurrence. Intraoperative and postoperative complications were noted. Early (< 7 days) and long-term clinical and radiological monitoring were performed. Good functional outcome was considered as a modified Rankin Scale score < 3.

RESULTS The mean age at initial treatment was 45 years (range 26–65 years). The mean delay between the first treatment and microsurgical treatment of the recurrence was 64 months (range 2 days–296 months). The mean size of the fundus recurrence was 5 mm, and the mean size of the neck recurrence was 4.6 mm. Five patients (8.3%) presented with subarachnoid hemorrhage associated with rupture of the recurrent aneurysm. Three patients died (6%) of aneurysm rupture and/or intensive care complications. The total morbidity rate associated with the microsurgical procedure was 14.5% (8/55) in patients with unruptured recurrent aneurysms. Among these patients, postoperative definitive complications (ischemic lesions) directly related to the microsurgical procedure were present in 3 patients (5.5%). Intraoperative rupture was recorded in these 3 patients. In the 54 surviving patients with unruptured recurrent aneurysms, good functional outcome was noted in 49 (91%). Poor functional outcome was significantly associated with intraoperative rupture.

CONCLUSIONS Microsurgery remains an effective therapeutic option for recurrent intracranial aneurysms. However, in the authors’ experience, postoperative morbidity is higher than in patients with nonrecurrent aneurysms. Therefore, a pretherapeutic multidisciplinary evaluation is mandatory to reduce the potential morbidity associated with the retreatment as much as possible. When endovascular occlusion of the aneurysm requires both stenting and coiling, alternative microsurgical treatment should be carefully evaluated, as microsurgical clipping will become much more challenging in cases of aneurysm recurrence.

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.

The learning curve for cavernous sinus surgery illustrated by symptomatic intracavernous aneurysm clipping through a pretemporal transcavernous approach

J Neurosurg 140:183–193, 2024

OBJECTIVE The anatomy of the cavernous sinus (CS) has been well studied in the laboratory for decades; however, performing surgery in and around the CS is still a challenge. To reveal the learning curve for CS surgery via the pretemporal transcavernous approach (PTTC), surgical procedures were examined. The authors proposed 4 levels of surgical difficulty in opening the walls of the CS through this approach. Details of the approach were illustrated by surgical videos of symptomatic intracavernous aneurysm clipping.

METHODS Four levels of surgical difficulty were proposed. The higher the level, the more the CS walls were opened. Pathologies corresponding to each level of difficulty in and around the CS were categorized in each level together with explanations. From 2015 to 2021, 5 patients with symptomatic intracavernous aneurysms (diplopia due to compressive cranial neuropathy) underwent the PTTC at the authors’ institute and served as representative cases in opening the walls of the CS. All CS cases from 2009 to 2021 were reviewed and categorized to demonstrate the learning curve.

RESULTS Four levels of surgical difficulty are as follows: level 1, a basic Dolenc extradural approach, which involves opening the anterior third of the superior and lateral walls of the CS; level 2, mobilizing the internal carotid artery (ICA) and opening the proximal dural ring to enter the roof of the CS and treat lesions around the clinoid and upper cavernous ICA; level 3, opening the entire aspect of the superior and lateral walls of the CS, which involves opening the oculomotor triangle and peeling the lateral wall of the CS to the tentorial incisura; and level 4, mobilizing cranial nerves III, IV, and V1 to gain access to the supra-/infratrochlear triangles to have proximal ICA control and opening the posterior wall as the last step to enter the posterior fossa. Surgical steps were described and illustrated with surgical videos of symptomatic intracavernous aneurysm clipping.

CONCLUSIONS The learning curve for CS surgery is long. The authors use 4 levels of surgical difficulty to describe applications of the PTTC in CS surgery. This approach serves as an effective workhorse in treating CS pathologies with low morbidity and high success rates when performed by experienced neurosurgeons.

Trends in the size of treated unruptured intracranial aneurysms over 35 years

J Neurosurg 139:1328–1338, 2023

In the absence of clear guidelines and consistent natural history data, the decision to treat unruptured intracranial aneurysms (UIAs) is a matter of some controversy. Currently, decisions are often guided by a consensus of cerebrovascular specialist teams and patient preferences. It is unclear how paradigm-shifting developments in the detection and treatment of UIAs have affected the size of the UIAs that are selected for treatment. Herein, the authors aimed to study potential changes in the average size of the UIAs that were treated over time. They hypothesized that the average size of UIAs that are treated is decreasing over time.

METHODS A systematic search of the literature was performed to identify all studies describing the size of UIAs that were treated using any modality. Scatter diagrams with trend lines were used to plot the size of the aneurysms treated over time and assess for the presence of a potentially significant trend via statistical correlation tests. Subgroup analyses based on type of treatment, country of study, and specialty of the authors were performed.

RESULTS A total of 240 studies including 35,150 UIAs treated between 1987 and 2021 met all eligibility criteria and were entered in the analysis. The mean age of patients was 55.5 years, and 70.7% of the patients were females. There was a significant decrease in the size of treated UIAs over time (Spearman’s r = −0.186, p < 0.001), with a 0.71-mm decrease in the average size of treated UIAs every 5 years since 1987 and an annual mean dropping below 7 mm in 2012. This decreasing trend was present in surgically and endovascularly treated UIAs (p < 0.001 for both), in more developed and developing countries (p < 0.001 for both), within neurosurgical and non-neurosurgical specialties (p < 0.001 for both), most prominently in the US (Spearman’s r = −0.482, p < 0.001), and less prominently in Europe (Spearman’s r = −0.221, p < 0.001) and was not detected in East Asia.

CONCLUSIONS The present study indicates that based on the treated UIA size data published in the literature over the past 35 years, smaller UIAs are being treated over time. This trend is likely driven by safer treatments. However, future studies should elucidate the cost-effectiveness of treating smaller UIAs as well as the possible real-world contribution of this trend in preventing aneurysmal subarachnoid hemorrhage.

Endovascular treatment of brain arteriovenous malformations: clinical outcomes of patients included in the registry of a pragmatic randomized trial

J Neurosurg 138:1393–1402, 2023

The role of endovascular treatment in the management of patients with brain arteriovenous malformations (AVMs) remains uncertain. AVM embolization can be offered as stand-alone curative therapy or prior to surgery or stereotactic radiosurgery (SRS) (pre-embolization). The Treatment of Brain AVMs Study (TOBAS) is an all-inclusive pragmatic study that comprises two randomized trials and multiple registries.

METHODS Results from the TOBAS curative and pre-embolization registries are reported. The primary outcome for this report is death or dependency (modified Rankin Scale [mRS] score > 2) at last follow-up. Secondary outcomes include angiographic results, perioperative serious adverse events (SAEs), and permanent treatment-related complications leading to an mRS score > 2.

RESULTS From June 2014 to May 2021, 1010 patients were recruited in TOBAS. Embolization was chosen as the primary curative treatment for 116 patients and pre-embolization prior to surgery or SRS for 92 patients. Clinical and angiographic outcomes were available in 106 (91%) of 116 and 77 (84%) of 92 patients, respectively. In the curative embolization registry, 70% of AVMs were ruptured, and 62% were low-grade AVMs (Spetzler-Martin grade I or II), while the pre-embolization registry had 70% ruptured AVMs and 58% low-grade AVMs. The primary outcome of death or disability (mRS score > 2) occurred in 15 (14%, 95% CI 8%–22%) of the 106 patients in the curative embolization registry (4 [12%, 95% CI 5%–28%] of 32 unruptured AVMs and 11 [15%, 95% CI 8%–25%] of 74 ruptured AVMs) and 9 (12%, 95% CI 6%–21%) of the 77 patients in the pre-embolization registry (4 [17%, 95% CI 7%–37%] of 23 unruptured AVMs and 5 [9%, 95% CI 4%–20%] of 54 ruptured AVMs) at 2 years. Embolization alone was confirmed to occlude the AVM in 32 (30%, 95% CI 21%–40%) of the 106 curative attempts and in 9 (12%, 95% CI 6%–21%) of 77 patients in the pre-embolization registry. SAEs occurred in 28 of the 106 attempted curative patients (26%, 95% CI 18%–35%, including 21 new symptomatic hemorrhages [20%, 95% CI 13%–29%]). Five of the new hemorrhages were in previously unruptured AVMs (n = 32; 16%, 95% CI 5%–33%). Of the 77 pre-embolization patients, 18 had SAEs (23%, 95% CI 15%–34%), including 12 new symptomatic hemorrhages [16%, 95% CI 9%–26%]). Three of the hemorrhages were in previously unruptured AVMs (3/23; 13%, 95% CI 3%–34%).

CONCLUSIONS Embolization as a curative treatment for brain AVMs was often incomplete. Hemorrhagic complications were frequent, even when the specified intent was pre-embolization before surgery or SRS. Because the role of endovascular treatment remains uncertain, it should preferably, when possible, be offered in the context of a randomized trial.

Transverse sinus stenting without surgical repair in idiopathic CSF rhinorrhea associated with transverse sinus stenoses

J Neurosurg 136:1745–1751, 2022

Based on their clinical and radiological patterns, idiopathic CSF rhinorrhea and idiopathic intracranial hypertension can represent different clinical expressions of the same underlying pathological process. Transverse sinus stenoses are associated with both diseases, resulting in eventual restriction of the venous CSF outflow pathway. While venous sinus stenting has emerged as a promising treatment for idiopathic intracranial hypertension, its efficiency on idiopathic CSF leaks has not been very well addressed in the literature so far. The purpose of this study was to report the results of transverse sinus stenting in patients with spontaneous CSF rhinorrhea associated with transverse sinus stenoses.

METHODS From a prospectively collected database, the authors retrospectively collected the clinical and radiological features of the patients with spontaneous CSF leakage who were treated with venous sinus stenting.

RESULTS Five female patients were included in this study. Transverse sinus stenoses were present in all patients, and other radiological signs of idiopathic intracranial hypertension were present in 4 patients. The median transstenotic pressure gradient was 6.5 mm Hg (range 3–9 mm Hg). Venous stenting resulted in the disappearance of the leak in 4 patients with no recurrence and no subsequent meningitis during the follow-up (median 12 months, range 6–63 months).

CONCLUSIONS According to the authors’ results, venous sinus stenting may result in the disappearance of the leak in many cases of idiopathic CSF rhinorrhea. Larger comparative studies are needed to assess the efficiency and safety of venous stenting as a first-line approach in patients with spontaneous CSF rhinorrhea associated with transverse sinus stenoses.