Long-term functional independence after minimally invasive endoscopic intracerebral hemorrhage evacuation

J Neurosurg 138:154–164, 2023

Intracerebral hemorrhage (ICH) is a devastating form of stroke with no proven treatment. However, minimally invasive endoscopic evacuation is a promising potential therapeutic option for ICH. Herein, the authors examine factors associated with long-term functional independence (modified Rankin Scale [mRS] score ≤ 2) in patients with spontaneous ICH who underwent minimally invasive endoscopic evacuation.

METHODS Patients with spontaneous supratentorial ICH who had presented to a large urban healthcare system from December 2015 to October 2018 were triaged to a central hospital for minimally invasive endoscopic evacuation. Inclusion criteria for this study included age ≥ 18 years, hematoma volume ≥ 15 ml, National Institutes of Health Stroke Scale (NIHSS) score ≥ 6, premorbid mRS score ≤ 3, and time from ictus ≤ 72 hours. Demographic, clinical, and radiographic factors previously shown to impact functional outcome in ICH were included in a retrospective univariate analysis with patients dichotomized into independent (mRS score ≤ 2) and dependent (mRS score ≥ 3) outcome groups, according to 6-month mRS scores. Factors that reached a threshold of p < 0.05 in a univariate analysis were included in a multivariate logistic regression.

RESULTS A total of 90 patients met the study inclusion criteria. The median preoperative hematoma volume was 41 (IQR 27–65) ml and the median postoperative volume was 1.2 (0.3–7.5) ml, resulting in a median evacuation percentage of 97% (85%–99%). The median hospital length of stay was 17 (IQR 9–25) days, and 8 (9%) patients died within 30 days of surgery. Twenty-four (27%) patients had attained functional independence by 6 months. Factors independently associated with long-term functional independence included lower NIHSS score at presentation (OR per point 0.78, 95% CI 0.67–0.91, p = 0.002), lack of intraventricular hemorrhage (IVH; OR 0.20, 95% CI 0.05–0.77, p = 0.02), and shorter time to evacuation (OR per hour 0.95, 95% CI 0.91–0.99, p = 0.007). Specifically, patients who had undergone evacuation within 24 hours of ictus demonstrated an mRS score ≤ 2 rate of 36% and were associated with an increased likelihood of long-term independence (OR 17.7, 95% CI 1.90–164, p = 0.01) as compared to those who had undergone evacuation after 48 hours.

CONCLUSIONS In a single-center minimally invasive endoscopic ICH evacuation cohort, NIHSS score on presentation, lack of IVH, and shorter time to evacuation were independently associated with functional independence at 6 months. Factors associated with functional independence may help to better predict populations suitable for minimally invasive endoscopic evacuation and guide protocols for future clinical trials.

The positive impact of cisternostomy with cisternal drainage on delayed hydrocephalus after aneurysmal subarachnoid hemorrhage

Acta Neurochirurgica (2023) 165:187–195

Hydrocephalus is one of the major complications of aneurysmal subarachnoid haemorrhage (aSAH). In the acute setting, an external ventricular drain (EVD) is used for early management. A cisternal drain (CD) coupled with the micro-surgical opening of basal cisterns can be an alternative when the aneurysm is clipped. Chronic hydrocephalus after aSAH is managed with ventriculo-peritoneal (VP) shunt, a procedure associated with a wide range of complications. The aim of this study is to analyse the impact of microsurgical opening of basal cisterns coupled with CD on the incidence of VP shunt, compared to patients treated with EVD.

Methods The authors conducted a retrospective review of 89 consecutive cases of patients with aSAH treated surgically and endovascularly with either EVD or CD between January 2009 and September 2021. Patients were stratified into two groups: Group 1 included patients with EVD, Group 2 included patients with CD. Subgroup analysis with only patients treated surgically was also performed. We compared their baseline characteristics, clinical outcomes and shunting rates.

Results There were no statistically significant differences between the two groups in terms of epidemiological characteristics, WFNS score, Fisher scale, presence of intraventricular hemorrhage (IVH), acute hydrocephalus, postoperative meningitis or of clinical outcomes at last follow-up. Cisternostomy with CD (Group 2) was associated with a statistically significant reduction in VP-shunt compared with the use of an EVD (Group 1) (9.09% vs 53.78%; p < 0.001). This finding was confirmed in our subgroup analysis, as among patients with a surgical clipping, the rate of VP shunt was 43.7% for the EVD group and 9.5% for the CD group (p = 0.02).

Conclusions Cisternostomy with CD may reduce the rate of shunt-dependent hydrocephalus. Cisternostomy allows the removal of subarachnoid blood, thereby reducing arachnoid inflammation and fibrosis. CD may enhance this effect, thus resulting in lower rates of chronic hydrocephalus.

Keywords Cisternostomy · Cisternal drain · External ventricular drain · Aneurysmal subarachnoid haemorrhage · Hydrocephalus · Ventriculo-peritoneal shunt

A quantitative model to differentiate nonaneurysmal perimesencephalic subarachnoid hemorrhage from aneurysmal etiology

J Neurosurg 138:165–172, 2023

OBJECTIVE Nonaneurysmal perimesencephalic subarachnoid hemorrhage (pmSAH) is considered to have a lower-risk pattern than other types of subarachnoid hemorrhage (SAH). However, a minority of patients with pmSAH may harbor a causative posterior circulation aneurysm. To exclude this possibility, many institutions pursue exhaustive imaging. In this study the authors aimed to develop a novel predictive model based on initial noncontrast head CT (NCHCT) features to differentiate pmSAH from aneurysmal causes.

METHODS The authors retrospectively reviewed patients admitted to an academic center for treatment of a suspected aneurysmal SAH (aSAH) during the period from 2016 to 2021. Patients with a final diagnosis of pmSAH or posterior circulation aSAH were included. Using NCHCT, the thickness (continuous variable) and location of blood in basal cisterns and sylvian fissures (categorical variables) were compared between groups. A scoring system was created using features that were significantly different between groups. Receiver operating characteristic curve analysis was used to measure the accuracy of this model in predicting aneurysmal etiology. A separate patient cohort was used for external validation of this model.

RESULTS Of 420 SAH cases, 48 patients with pmSAH and 37 with posterior circulation aSAH were identified. Blood thickness measurements in the crural and ambient cisterns and interhemispheric and sylvian fissures and degree of extension into the sylvian fissure were all significantly different between groups (all p < 0.001). The authors developed a 10-point scoring model to predict aneurysmal causes with high accuracy (area under the curve [AUC] 0.99; 95% CI 0.98–1.00; OR per point increase 10; 95% CI 2.18–46.4). External validation resulted in persistently high accuracy (AUC 0.97; 95% CI 0.92–1.00) of this model.

CONCLUSIONS A risk stratification score using initial blood clot burden may accurately differentiate between aneurysmal and nonaneurysmal pmSAH. Larger prospective studies are encouraged to further validate this quantitative tool.

Chronic Encapsulated Expanding Hematomas After Stereotactic Radiosurgery for Intracranial Arteriovenous Malformations

Neurosurgery 92:195–204, 2023

Stereotactic radiosurgery (SRS) offers a minimally invasive treatment modality for appropriately selected intracranial arteriovenous malformations (AVMs). Recent reports have described the development of rare, delayed chronic encapsulated expanding hematomas (CEEHs) at the site of an angiographically confirmed obliterated AVM.

OBJECTIVE: To elucidate the incidence, characteristics, and management of CEEH in patients with AVM after SRS.

METHODS: The records of all patients who underwent SRS for an intracranial AVM at 4 institutions participating in the International Radiosurgery Research Foundation between 1987 and 2021 were retrospectively reviewed. Data regarding characteristics of the AVM, SRS treatment parameters, CEEH presentation, management, and outcomes were collected and analyzed.

RESULTS: Among 5430 patients, 15 developed a CEEH at a crude incidence of 0.28%. Nine patients were female, and the mean age was 43 ± 14.6 years. Nine patients underwent surgical evacuation, while 6 were managed conservatively. The median CEEH development latency was 106 months after SRS. The patients were followed for a median of 32 months, and 9 patients improved clinically, while 6 patients remained stable. No intraoperative complications were reported after CEEH resection, although 1 patient recovered from postoperative meningitis requiring intravenous antibiotics.

CONCLUSION: CEEH is a rare, late complication of AVM SRS with an incidence of 0.28% and a median latency of 106 months. In the presence of a delayed and symptomatic expanding hematoma in the bed of an angiographically obliterated AVM, surgical resection resulted in clinical improvement in most patients. Conservative management is possible in asymptomatic patients with stable, small-sized hematomas in deeply seated locations.

A taxonomy for brainstem cavernous malformations: subtypes of medullary lesions

J Neurosurg 138:128–146, 2023

Medullary cavernous malformations are the least common of the brainstem cavernous malformations (BSCMs), accounting for only 14% of lesions in the authors’ surgical experience. In this article, a novel taxonomy for these lesions is proposed based on clinical presentation and anatomical location.

METHODS The taxonomy system was applied to a large 2-surgeon experience over a 30-year period (1990–2019). Of 601 patients who underwent microsurgical resection of BSCMs, 551 were identified who had the clinical and radiological information needed for inclusion. These 551 patients were classified by lesion location: midbrain (151 [27%]), pons (323 [59%]), and medulla (77 [14%]). Medullary lesions were subtyped on the basis of their predominant surface presentation. Neurological outcomes were assessed according to the modified Rankin Scale (mRS), with an mRS score ≤ 2 defined as favorable.

RESULTS Five distinct subtypes were defined for the 77 medullary BSCMs: pyramidal (3 [3.9%]), olivary (35 [46%]), cuneate (24 [31%]), gracile (5 [6.5%]), and trigonal (10 [13%]). Pyramidal lesions are located in the anterior medulla and were associated with hemiparesis and hypoglossal nerve palsy. Olivary lesions are found in the anterolateral medulla and were associated with ataxia. Cuneate lesions are located in the posterolateral medulla and were associated with ipsilateral upper-extremity sensory deficits. Gracile lesions are located outside the fourth ventricle in the posteroinferior medulla and were associated with ipsilateral lower-extremity sensory deficits. Trigonal lesions in the ventricular floor were associated with nausea, vomiting, and diplopia. A single surgical approach was preferred (> 90% of cases) for each medullary subtype: the far lateral approach for pyramidal and olivary lesions, the suboccipital-telovelar approach for cuneate lesions, the suboccipital-transcisterna magna approach for gracile lesions, and the suboccipital-transventricular approach for trigonal lesions. Of these 77 patients for whom follow-up data were available (n = 73), 63 (86%) had favorable outcomes and 67 (92%) had unchanged or improved functional status.

CONCLUSIONS This study confirms that the constellation of neurological signs and symptoms associated with a hemorrhagic medullary BSCM subtype is useful for defining the BSCM clinically according to a neurologically recognizable syndrome at the bedside. The proposed taxonomical classifications may be used to guide the selection of surgical approaches, which may enhance the consistency of clinical communications and help improve patient outcomes.

Microsurgery versus Microsurgery With Preoperative Embolization for Brain Arteriovenous Malformation Treatment: A Systematic Review and Meta-analysis

Neurosurgery 92:27–41, 2023

Preoperative embolization has traditionally been regarded as a safe and effective adjunct to microsurgical treatment of brain arteriovenous malformations (bAVM). However, there is currently no high-level evidence to ascertain this presumption.

OBJECTIVE: To compare the outcomes of microsurgery (MS) vs microsurgery with preoperative embolization (E + MS) in patients with bAVM through systematic review.

METHODS: We searched MEDLINE, PubMed, and Embase. The primary outcome was bAVM obliteration. Secondary outcomes were intraoperative bleeding (mL), complications, worsened modified Rankin Scale (mRS), and mortality. The pooled proportions of outcomes were calculated through the logit transformation method. The odds ratio (OR) of categorical data and mean difference of continuous data were estimated through the Mantel-Haenszel and the inverse variance methods, respectively.

RESULTS: Thirty-two studies met the eligibility criteria. One thousand eight hundred twenty-eight patients were treated by microsurgery alone, and 1088 were treated by microsurgery with preoperative embolization, respectively. The meta-analysis revealed no significant difference in AVM obliteration (94.1% vs 95.6%, OR = 1.15 [0.63-2.11], P = .65), mortality (1.7% vs 2%, OR = 0.88 [0.30-2.58], P = .82), procedural complications (18.2% vs 27.2%, OR = 0.47 [0.19-1.17], P = .10), worsened mRS (21.2% vs 18.5%, OR = 1.08 [0.33-3.54], P = .9), and intraoperative blood loss (mean difference = 182.89 [À87.76, 453.55], P = .19).

CONCLUSION: The meta-analysis showed no significant difference in AVM obliteration, mortality, complications, worse mRS, and intraoperative blood loss between MS and E + MS groups. For AVMs where MS alone has acceptable results, it is reasonable to bypass unnecessary preoperative embolization given higher postoperative complication risk.

Risk for Hemorrhage the First 2 Years After Gamma Knife Surgery for Arteriovenous Malformations: An Update

Neurosurgery 91:920–927, 2022

Knowledge about the natural course of brain arteriovenous malformations (AVMs) have increased during the past 20 years, as has the number of AVMs treated, especially larger ones. It is thus timely to again analyze the risk for hemorrhage after Gamma Knife Surgery (GKS).

OBJECTIVE: To confirm or contradict conclusions drawn 20 years ago regarding factors that affect the risk for post-GKS hemorrhage.

METHODS: The outcome after GKS was studied in 5037 AVM patients followed for up to 2 years. The relation between post-treatment hemorrhage rate and a number of patient, AVM, and treatment parameters was analyzed. The results were also compared with the results from our earlier study.

RESULTS: The annual post-treatment hemorrhage rate was 2.4% the first 2 years after GKS. Large size, low treatment dose, and old age were independent risk factors for AVM hemorrhage. After having compensated for the factors above, peripheral AVM location and female sex, at least during their child bearing ages, were factors associated with a lower post-GKS hemorrhage rate.

CONCLUSION: Large AVMs (>5 cm3) treated with low doses (≤16 Gy) had higher and small AVMs treated with high doses a lower risk for hemorrhage as compared with untreated AVMs. This was detectable within the first 6 months after GKS. No difference in hemorrhage rate could be detected for the other AVMs. Based on our findings, it is advisable to prescribe >16 Gy to larger AVMs, assuming that the risk for radiation-induced complications can be kept at an acceptable level.

Management of Chronic Subdural Hematoma: A Systematic Review and Component Network Meta-analysis of 455 Studies With 103 645 Cases

Neurosurgery 91:842–855, 2022

Chronic subdural hematoma (CSDH) is a common neurosurgical condition with a high risk of recurrence after treatment.

OBJECTIVE: To assess and compare the risk of recurrence, morbidity, and mortality across various treatments for CSDH.

METHODS: A systematic review and meta-analysis was performed. PubMed/MEDLINE, EMBASE, SCOPUS, and Web of Science were searched from January 01, 2000, to July 07, 2021. The primary outcome was recurrence, and secondary outcomes were morbidity and mortality. Component network meta-analyses (CNMAs) were performed for surgical and medical treatments, assessing recurrence and morbidity. Incremental risk ratios (iRRs) with 95% CIs were estimated for each component.

RESULTS: In total, 12 526 citations were identified, and 455 studies with 103 645 cases were included. Recurrence occurred in 11 491/93 525 (10.8%, 95% CI 10.2-11.5, 418 studies) cases after surgery. The use of a postoperative drain (iRR 0.53, 95% CI 0.44-0.63) and middle meningeal artery embolization (iRR 0.19, 95% CI 0.05-0.83) reduced recurrence in the surgical CNMA. In the pharmacological CNMA, corticosteroids (iRR 0.47, 95% CI 0.36- 0.61) and surgical intervention (iRR 0.11, 95% CI 0.07-0.15) were associated with lower risk. Corticosteroids were associated with increased morbidity (iRR 1.34, 95% CI 1.05-1.70). The risk of morbidity was equivalent across surgical treatments.

CONCLUSION: Recurrence after evacuation occurs in approximately 10% of cSDHs, and the various surgical interventions are approximately equivalent. Corticosteroids are associated with reduced recurrence but also increased morbidity. Drains reduce the risk of recurrence, but the position of drain (subdural vs subgaleal) did not influence recurrence. Middle meningeal artery embolization is a promising treatment warranting further evaluation in randomized trials.

 

Stereotactic Radiosurgery for A Randomized Trial of Unruptured Brain Arteriovenous Malformations- Eligible Patients: A Meta-Analysis

Neurosurgery 91:684–692, 2022

The outcomes of A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) were controversial, and they suggested that intervention is inferior to medical management for unruptured brain arteriovenous malformations (AVMs). However, several studies have shown that stereotactic radiosurgery (SRS) is an acceptable therapy for unruptured AVMs.

OBJECTIVE: To test the hypothesis that ARUBA intervention arm’s SRS results are meaningfully inferior to those from similar populations reported by other studies.

METHODS: We performed a literature review to identify SRS studies of patients who met the eligibility criteria for ARUBA. Patient, AVM, treatment, and outcome data were extracted for statistical analysis. Regression analyses were pooled to identify factors associated with post-SRS obliteration and hemorrhage.

RESULTS: The study cohort included 8 studies comprising 1620 ARUBA-eligible patients who underwent SRS. At the time of AVM diagnosis, 36% of patients were asymptomatic. The mean follow-up duration was 80 months. Rates of radiologic, symptomatic, and permanent radiation-induced changes were 45%, 11%, and 2%, respectively. The obliteration rate was 68% at last follow-up. The post-SRS hemorrhage and mortality rates were 8%, and 2%, respectively. Lower Spetzler-Martin grade (odds ratios [OR] = 0.84 [0.74-0.95], P = .005), lower radiosurgery-based AVM score (OR = 0.75 [0.64-0.95], P = .011), lower Virginia Radiosurgery AVM Scale (OR = 0.86 [0.78-0.95], P = .003), and higher margin dose (OR = 1.13 [1.02-1.25], P = .025) were associated with obliteration.

CONCLUSION: SRS carries a favorable risk to benefit profile for appropriately selected ARUBA-eligible patients, particularly those with smaller volume AVMs. Our findings suggest that the results of ARUBA do not reflect the real-world safety and efficacy of SRS for unruptured AVMs.

Venous Sinus Stenting for Low Pressure Gradient Stenoses in Idiopathic Intracranial Hypertension

Neurosurgery 91:734–740, 2022

Medically refractory idiopathic intracranial hypertension (IIH) is frequently treated with venous sinus stenosis stenting with high success rates. Patient selection has been driven almost exclusively by identification of supraphysiological venous pressure gradients across stenotic regions based on theoretical assessment of likelihood of response.

OBJECTIVE: To explore the possibility of benefit in low venous pressure gradient patients.

METHODS: Using a single-center, prospectively maintained registry of patients with IIH undergoing venous stenting, we defined treatment groups by gradient pressures of ≤4, 5 to 8, and >8 mmHg based on the most frequently previously published thresholds for stenting. Baseline demographics, clinical, and neuro-ophthalmological outcomes (including optical coherence tomography and Humphrey visual fields) were compared.

RESULTS: Among 53 patients, the mean age was 32 years and 70% female with a mean body mass index was 36 kg/m2 . Baseline characteristics were similar between groups. The mean change in lumbar puncture opening pressure at 6 months poststenting was similar between the 3 groups (≤4, 5-8, and >8 mmHg; 13.4, 12.9, and 12.4 cmH2 O, P=.47). Papilledema improvement was observed across groups at 6 months (100, 93, and 86, P = .7) as were all clinical symptoms. The mean changes in optical coherence tomography retinal nerve fiber layer (À30, À54, and À104, P = .5) and mean deviation in Humphrey visual fields (60, 64, and 67, P = .5) at 6 weeks were not significantly different.

CONCLUSION: Patients with IH with low venous pressure gradient venous sinus stenosis seem to benefit equally from venous stenting compared with their higher gradient counterparts. Re-evaluation of our restrictive criteria for this potentially vision sparing intervention is warranted. Future prospective confirmatory studies are needed.

A taxonomy for brainstem cavernous malformations: subtypes of pontine lesions. Part 1: basilar, peritrigeminal, and middle peduncular

J Neurosurg 137:1462–1476, 2022

Brainstem cavernous malformations (BSCMs) are complex, difficult to access, and highly variable in size, shape, and position. The authors have proposed a novel taxonomy for pontine cavernous malformations (CMs) based upon clinical presentation (syndromes) and anatomical location (findings on MRI).

METHODS The proposed taxonomy was applied to a 30-year (1990–2019), 2-surgeon experience. Of 601 patients who underwent microsurgical resection of BSCMs, 551 with appropriate data were classified on the basis of BSCM location: midbrain (151 [27%]), pons (323 [59%]), and medulla (77 [14%]). Pontine lesions were then subtyped on the basis of their predominant surface presentation identified on preoperative MRI. Neurological outcomes were assessed according to the modified Rankin Scale, with a score ≤ 2 defined as favorable.

RESULTS The 323 pontine BSCMs were classified into 6 distinct subtypes: basilar (6 [1.9%]), peritrigeminal (53 [16.4%]), middle peduncular (MP) (100 [31.0%]), inferior peduncular (47 [14.6%]), rhomboid (80 [24.8%]), and supraolivary (37 [11.5%]). Part 1 of this 2-part series describes the taxonomic basis for the first 3 of these 6 subtypes of pontine CM. Basilar lesions are located in the anteromedial pons and associated with contralateral hemiparesis. Peritrigeminal lesions are located in the anterolateral pons and are associated with hemiparesis and sensory changes. Patients with MP lesions presented with mild anterior inferior cerebellar artery syndrome with contralateral hemisensory loss, ipsilateral ataxia, and ipsilateral facial numbness without cranial neuropathies. A single surgical approach and strategy were preferred for each subtype: for basilar lesions, the pterional craniotomy and anterior transpetrous approach was preferred; for peritrigeminal lesions, extended retrosigmoid craniotomy and transcerebellopontine angle approach; and for MP lesions, extended retrosigmoid craniotomy and trans–middle cerebellar peduncle approach. Favorable outcomes were observed in 123 of 143 (86%) patients with follow-up data. There were no significant differences in outcomes between the 3 subtypes or any other subtypes.

CONCLUSIONS The neurological symptoms and key localizing signs associated with a hemorrhagic pontine subtype can help to define that subtype clinically. The proposed taxonomy for pontine CMs meaningfully guides surgical strategy and may improve patient outcomes.

Efficacy and safety of the endoscopic “wet‑field” technique for removal of supratentorial cavernous malformations

Acta Neurochirurgica (2022) 164:2587–2594

Cerebral cavernous malformations (CMs) presenting with focal neurological symptoms or mass effects require surgical removal. In recent years, cylindrical retractors have been widely utilized for the removal of deep-seated lesions during both microscopic and endoscopic surgery. In the present study, we evaluated the efficacy and safety of endoscopic transcylinder removal of CMs using a novel wet-field technique.

Methods We included 13 patients with supratentorial CMs who had undergone endoscopic transcylinder surgery between April 2013 and March 2022. One patient experienced recurrence of the CM and underwent a second endoscopic transcylinder surgery. Therefore, we retrospectively evaluated 14 procedures. The surgical field was continuously irrigated with artificial cerebrospinal fluid to maintain expansion and visualization of the tumor bed. We termed this method as the “wet-field technique.” Patient characteristics, symptoms, and pre- and postoperative magnetic resonance imaging results were obtained from medical records.

Results The average maximum CM diameter was 35.3 mm (range: 10–65 mm). Cylinder diameters were 6 mm in eight procedures, 10 mm in four procedures, and 17 mm in one procedure. Wet-field technique was applied in all cases. The endoscope provided a bright field of view even under water. Continuous water irrigation made it easier to observe the entire tumor bed which naturally expanded by water pressure. Gross total resection was achieved in 13 procedures, while subtotal resection was achieved in one procedure. No surgical complications were observed.

Conclusions The endoscopic transcylinder removal using wet-field technique is safe and effective for the removal of symptomatic intracranial supratentorial CMs.

Medication intake and hemorrhage risk in patients with familial cerebral cavernous malformations

J Neurosurg 137:1088–1094, 2022

The objective of this study was to analyze the impact of medication intake on hemorrhage risk in patients with familial cerebral cavernous malformation (FCCM).

METHODS The authors’ institutional database was screened for patients with FCCM who had been admitted to their department between 2003 and 2020. Patients with a complete magnetic resonance imaging (MRI) data set, evidence of multiple CCMs, clinical baseline characteristics, and follow-up (FU) examination were included in the study. The authors assessed the influence of medication intake on first or recurrent intracerebral hemorrhage (ICH) using univariate and multivariate logistic regression adjusted for age and sex. The longitudinal cumulative 5-year risk of hemorrhage was calculated by applying Kaplan-Meier and Cox regression analyses adjusted for age and sex.

RESULTS Two hundred five patients with FCCMs were included in the study. Multivariate Cox regression analysis revealed ICH as a predictor for recurrent hemorrhage during the 5-year FU. The authors also noted a tendency toward a decreased association with ICH during FU in patients on statin medication (HR 0.22, 95% CI 0.03–1.68, p = 0.143), although the relationship was not statistically significant. No bleeding events were observed in patients on antithrombotic therapy. Kaplan-Meier analysis and log-rank test showed a tendency toward a low risk of ICH during FU in patients on antithrombotic therapy (p = 0.085), as well as those on statin therapy (p = 0.193). The cumulative 5-year risk of bleeding was 22.82% (95% CI 17.33%–29.38%) for the entire cohort, 31.41% (95% CI 23.26%–40.83%) for patients with a history of ICH, 26.54% (95% CI 11.13%–49.7%) for individuals on beta-blocker medication, 6.25% (95% CI 0.33%–32.29%) for patients on statin medication, and 0% (95% CI 0%–30.13%) for patients on antithrombotic medication.

CONCLUSIONS ICH at diagnosis was identified as a risk factor for recurrent hemorrhage. Although the relationships were not statistically significant, statin and antithrombotic medication tended to be associated with decreased bleeding events.

Development and Internal Validation of the ARISE Prediction Models for Rebleeding After Aneurysmal Subarachnoid Hemorrhage

Neurosurgery 91:450–458, 2022

Aneurysmal rerupture is one of the most important determents for outcome after aneurysmal subarachnoid hemorrhage and still occurs frequently because individual risk assessment is challenging given the heterogeneity in patient characteristics and aneurysm morphology.

OBJECTIVE: To develop and internally validate a practical prediction model to estimate the risk of aneurysmal rerupture before aneurysm closure.

METHODS: We designed a multinational cohort study of 2 prospective hospital registries and 3 retrospective observational studies to predict the risk of computed tomography confirmed rebleeding within 24 and 72 hours after ictus. We assessed predictors with Cox proportional hazard regression analysis.

RESULTS: Rerupture occurred in 269 of 2075 patients. The cumulative incidence equaled 7% and 11% at 24 and 72 hours, respectively. Our base model included hypertension, World Federation of Neurosurgical Societies scale, Fisher grade, aneurysm size, and cerebrospinal fluid drainage before aneurysm closure and showed good discrimination with an optimism corrected c-statistic of 0.77. When we extend the base model with aneurysm irregularity, the optimism-corrected c-statistic increased to 0.79.

CONCLUSION: Our prediction models reliably estimate the risk of aneurysm rerupture after aneurysmal subarachnoid hemorrhage using predictor variables available upon hospital admission. An online prognostic calculator is accessible at https://www.evidencio. com/models/show/2626.

 

Stability of unruptured intracranial aneurysms in the anterior circulation: nomogram models for risk assessment

J Neurosurg 137:675–684, 2022

The probable stability of the lesion is critical in guiding treatment decisions in unruptured intracranial aneurysms (IAs). The authors aimed to develop multidimensional predictive models for the stability of unruptured IAs.

METHODS Patients with unruptured IAs in the anterior circulation were prospectively enrolled and regularly followed up. Clinical data were collected, IA morphological features were assessed, and adjacent hemodynamic features were quantified with patient-specific computational fluid dynamics modeling. Based on multivariate logistic regression analyses, nomograms incorporating these factors were developed in a primary cohort (patients enrolled between January 2017 and February 2018) to predict aneurysm rupture or growth within 2 years. The predictive accuracies of the nomograms were compared with the population, hypertension, age, size, earlier rupture, and site (PHASES) and earlier subarachnoid hemorrhage, location, age, population, size, and shape (ELAPSS) scores and validated in the validation cohort (patients enrolled between March and October 2018).

RESULTS Among 231 patients with 272 unruptured IAs in the primary cohort, hypertension, aneurysm location, irregular shape, size ratio, normalized wall shear stress average, and relative resident time were independently related to the 2-year stability of unruptured IAs. The nomogram including clinical, morphological, and hemodynamic features (C+M+H nomogram) had the highest predictive accuracy (c-statistic 0.94), followed by the nomogram including clinical and morphological features (C+M nomogram; c-statistic 0.89), PHASES score (c-statistic 0.68), and ELAPSS score (c-statistic 0.58). Similarly, the C+M+H nomogram had the highest predictive accuracy (c-statistic 0.94) in the validation cohort (85 patients with 97 unruptured IAs).

CONCLUSIONS Hemodynamics have predictive values for 2-year stability of unruptured IAs treated conservatively. Multidimensional nomograms have significantly higher predictive accuracies than conventional risk prediction scores.

 

Wall enhancement in unruptured posterior communicating aneurysms with oculomotor nerve palsy on magnetic resonance vessel wall imaging

J Neurosurg 137:668–674, 2022

Recent MR vessel wall imaging studies of unruptured intracranial aneurysms (UIAs) have revealed that aneurysm wall enhancement (AWE) can be an indicator for aneurysm evolution; however, the degree of AWE among different types of evolving UIAs has yet to be clarified. The authors assessed the degree of AWE in unruptured posterior communicating artery (PcomA) aneurysms with oculomotor nerve palsy (ONP), which may be a subgroup of evolving UIAs with rapid enlargement and high rupture risk.

METHODS The degree of AWE was analyzed in 35 consecutive evolving PcomA aneurysms (19 with and 16 without ONP). UIAs were considered to be evolving when showing growth or ONP. A 3D T1-weighted fast spin echo sequence was obtained after contrast media injection, and the contrast ratio of the aneurysm wall against the pituitary stalk (CR stalk ) was calculated as the indicator of AWE. The CR stalk in evolving UIAs with ONP was compared with that in UIAs without ONP.

RESULTS The CR stalk was significantly higher in evolving UIAs with ONP than in those without ONP (0.85 vs 0.57; p =0.006). In multivariable analysis, the CR stalk remained a significant indicator for ONP presentation in evolving UIAs (OR 6.13, 95% CI 1.21–31.06).

CONCLUSIONS AWE was stronger in evolving PcomA aneurysms with ONP than in those without ONP, suggesting the potential utility of AWE for risk stratification in evolving UIAs. The degree of AWE can be a promising indicator of a rupture-prone UIA, which can be useful information for the decision-making process in the treatment of UIAs.

Microvascular anatomy of the medial temporal region

J Neurosurg 137:747–759, 2022

The authors investigated the microvascular anatomy of the hippocampus and its implications for medial temporal tumor surgery. They aimed to reveal the anatomical variability of the arterial supply and venous drainage of the hippocampus, emphasizing its clinical implications for the removal of associated tumors.

METHODS Forty-seven silicon-injected cerebral hemispheres were examined using microscopy. The origin, course, irrigation territory, spatial relationships, and anastomosis of the hippocampal arteries and veins were investigated. Illustrative cases of hippocampectomy for medial temporal tumor surgery are also provided.

RESULTS The hippocampal arteries can be divided into 3 segments, the anterior (AHA), middle (MHA), and posterior (PHA) hippocampal artery complexes, which correspond to irrigation of the hippocampal head, body, and tail, respectively. The uncal hippocampal and anterior hippocampal-parahippocampal arteries contribute to the AHA complex, the posterior hippocampal-parahippocampal arteries serve as the MHA complex, and the PHA and splenial artery compose the PHA complex. Rich anastomoses between hippocampal arteries were observed, and in 11 (23%) hemispheres, anastomoses between each segment formed a complete vascular arcade at the hippocampal sulcus. Three veins were involved in hippocampal drainage—the anterior hippocampal, anterior longitudinal hippocampal, and posterior longitudinal hippocampal veins—which drain the hippocampal head, body, and tail, respectively, into the basal and internal cerebral veins.

CONCLUSIONS An understanding of the vascular variability and network of the hippocampus is essential for medial temporal tumor surgery via anterior temporal lobectomy with amygdalohippocampectomy and transsylvian selective amygdalohippocampectomy. Stereotactic procedures in this region should also consider the anatomy of the vascular arcade at the hippocampal sulcus.

Microsurgical treatment of ruptured aneurysms beyond 72 hours after rupture: implications for advanced management

Acta Neurochirurgica (2022) 164:2431–2439

Aneurysmal subarachnoid hemorrhage (aSAH) patients admitted to primary stroke centers are often transferred to neurosurgical and endovascular services at tertiary centers. The effect on microsurgical outcomes of the resultant delay in treatment is unknown. We evaluated microsurgical aSAH treatment > 72 h after the ictus.

Methods All aSAH patients treated at a single tertiary center between August 1, 2007, and July 31, 2019, were retrospectively reviewed. The additional inclusion criterion was the availability of treatment data relative to time of bleed. Patients were grouped based on bleed-to-treatment time as having acute treatment (on or before postbleed day [PBD] 3) or delayed treatment (on or after PBD 4). Propensity adjustments were used to correct for statistically significant confounding covariables.

Results Among 956 aSAH patients, 92 (10%) received delayed surgical treatment (delayed group), and 864 (90%) received acute endovascular or surgical treatment (acute group). Reruptures occurred in 3% (26/864) of the acute group and 1% (1/92) of the delayed group (p = 0.51). After propensity adjustments, the odds of residual aneurysm (OR = 0.09; 95% CI = 0.04–0.17; p < 0.001) or retreatment (OR = 0.14; 95% CI = 0.06–0.29; p < 0.001) was significantly lower among the delayed group. The OR was 0.50 for rerupture, after propensity adjustments, in the delayed setting (p = 0.03). Mean Glasgow Coma Scale scores at admission in the acute and delayed groups were 11.5 and 13.2, respectively (p < 0.001).

Conclusions Delayed microsurgical management of aSAH, if required for definitive treatment, appeared to be noninferior with respect to retreatment, residual, and rerupture events in our cohort after adjusting for initial disease severity and significant confounding variables.

Cost Comparison of Microsurgery vs Endovascular Treatment for Ruptured Intracranial Aneurysms: A Propensity-Adjusted Analysis

Neurosurgery 91:470–476, 2022

In specialized neurosurgical centers, open microsurgery is routinely performed for aneurysmal subarachnoid hemorrhage (aSAH).

OBJECTIVE: To compare the cost of endovascular vs microsurgical treatment for aSAH at a single quaternary center.

METHODS: All patients undergoing aSAH treatment from July 1, 2014, to July 31, 2019, were retrospectively reviewed. Patients were grouped based on primary treatment (microsurgery vs endovascular treatment). The primary outcomewas the difference in total cost (including hospital, discharge facility, and all follow-up) using a propensity-adjusted analysis.

RESULTS: Of 384 patients treated for an aSAH, 234 (61%) were microsurgically treated and 150 (39%) were endovascularly treated. The mean cost of index hospitalization for these patients was marginally higher ($9504) for endovascularly treated patients ($103 980) than for microsurgically treated patients ($94 476) (P = .047). For the subset of patients with follow-up data available, the mean total cost was $45 040 higher for endovascularly treated patients ($159 406, n = 59) than that for microsurgically treated patients ($114 366, n = 105) (P < .001). After propensity scoring (adjusted for age, sex, comorbidities, Glasgow Coma Scale score, Hunt and Hess grade, Fisher grade, aneurysms, and type/size/location), linear regression analysis of patients with follow-up data available revealed that microsurgery was independently associated with healthcare costs that were $37 244 less than endovascular treatment costs (P < .001). An itemized cost analysis suggested that this discrepancy was due to differences in the rates of aneurysm retreatment and long-term surveillance.

CONCLUSION: Microsurgical treatment for aSAH is associated with lower total healthcare costs than endovascular therapy. Aneurysm surveillance after endovascular treatments, retreatment, and device costs warrants attention in future studies.

Randomized Trial Comparing Burr Hole Craniostomy, Minicraniotomy, and Twist Drill Craniostomy for Treatment of Chronic Subdural Hematoma

Neurosurgery 91:304–311, 2022

The mainstay of treatment for symptomatic or large chronic subdural hematoma (CSDH) is surgery, but controversy still exists regarding the best surgical technique. Three different techniques are commonly used: burr hole craniostomy (BHC), minicraniotomy (MC), and twist drill craniostomy (TDC).

OBJECTIVE: To determine which surgical technique for drainage of CSDH offers best results.

METHODS: We set up a multicenter prospective randomized trial (Comparison of Chronic Subdural Hematoma Treatment [COMPACT] trial) comparing BHC, MC, and TDC for the surgical treatment of CSDH. The primary end point was reoperation rate, and secondary end points included complication rates and clinical outcome. Patients were considered to have good outcome when they did not undergo reoperation, suffered no surgical or medical complication, and had no related mortality. Clinical outcome was also evaluated by evolution of the Markwalder score and the modified Rankin score.

RESULTS: Two-hundred forty-five patients were included in the final analysis: 79 BHC, 84 MC, and 82 TDC. Mean duration of surgery was shorter for TDC than for BHC and MC (P < .001). Reoperation rate was 7.6% for BHC, 13.1% for MC, and 19.5% for TDC (P = .07). This trend toward better results for BHC was not statistically significant in logistic regression analysis. The proportion of patients with good outcome was 78.5% for BHCgroup, 76.2% for MC, and 69.5% for TDC (P = .4). Evolution of the Markwalder score and modified Rankin score were not significantly different between treatment groups.

CONCLUSION: All 3 techniques are effective at treating patients with CSDH with eventual 6-month outcome being similar. Although not reaching statistical significance in our study, BHC offers the lowest recurrence rate combined with manageable complication rate.