Category: Vascular

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Unruptured intracranial aneurysms in patients over 80 years

Acta Neurochirurgica (2018) 160:1773–1777

Patients over the age of 80 years when diagnosed with an unruptured intracranial aneurysm (UIA) pose unique decisionmaking challenges due to shortened life-expectancy and increased risk of treatment. Thus, we investigated the risk of rupture and survival of a consecutive series of patients who were diagnosed with an UIA after the age of 80 years.

Methods Data of consecutive patients with an UIA were reviewed, and patients were included in our study if they were first evaluated for a UIA by the senior author during their ninth decade of life. Outcomes were aneurysm rupture and overall survival after diagnosis. Survival was estimated from a Kaplan-Meier survival curve. Incidence of risk factors was compared to a population of patients less than 65 years who were seen by the senior author over the same time period.

Results Eighty-three patients who were over 80 years when diagnosed with a UIA were included in this study. In our population, there is a risk of rupture of 3.2% per patient-year. One-, three-, and five-year survival rates for our population were estimated to be 92, 64, and 35%, respectively. When compared to patients under 65 years diagnosed with a UIA, Bover 80^ patients had a significantly higher incidence of hypertension, and a significantly lower incidence of smoking history and familial aneurysm history.

Conclusions In our study population, UIAs greater than 7 mm carry a non-negligible risk of rupture of 3.2% per patient-year, and further studies investigating the risk-to-benefit ratio of treatment in this population are warranted.

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Effect of body mass index on outcome after aneurysmal subarachnoid hemorrhage treated with clipping versus coiling

J Neurosurg 129:658–669, 2018

It has been suggested that increased body mass index (BMI) may confer a protective effect on patients who suffer from aneurysmal subarachnoid hemorrhage (aSAH). Whether the modality of aneurysm occlusion influences the effect of BMI on patient outcomes is not well understood. The authors aimed to compare the effect of BMI on outcomes for patients with aSAH treated with surgical clipping versus endovascular coiling.

METHODS The authors retrospectively reviewed the outcomes for patients admitted to their institution for the management of aSAH treated with either clipping or coiling. BMI at the time of admission was recorded and used to assign patients to a group according to low or high BMI. Cutoff values for BMI were determined by classification and regression tree analysis. Predictors of poor functional outcome (defined as modified Rankin Scale score > 2 measured ≥ 90 days after the ictus) and posttreatment cerebral hypodensities detected during admission were then determined separately for patients treated with clipping or coiling using stepwise multivariate logistic regression analysis.

RESULTS Of the 469 patients admitted to the authors’ institution with aSAH who met the study’s inclusion criteria, 144 were treated with clipping and 325 were treated with coiling. In the clipping group, the frequency of poor functional outcome was higher in patients with BMI ≥ 32.3 kg/m2 (47.6% vs 19.0%; p = 0.007). In contrast, in the coiling group, patients with BMI ≥ 32.3 kg/m2 had a lower frequency of poor functional outcome at ≥ 90 days (5.8% vs 30.9%; p < 0.001). On multivariate analysis, high BMI was independently associated with an increased (OR 3.92, 95% CI 1.20–13.41; p = 0.024) and decreased (OR 0.13, 95% CI 0.03–0.40; p < 0.001) likelihood of poor functional outcome for patients treated with clipping and coiling, respectively. For patients in the surgical group, BMI ≥ 28.4 kg/m2 was independently associated with incidence of cerebral hypodensities during admission (OR 2.44, 95% CI 1.16–5.25; p = 0.018) on multivariate analysis. For patients treated with coiling, BMI ≥ 33.2 kg/m2 was independently associated with reduced odds of hypodensities (OR 0.45, 95% CI 0.21–0.89; p = 0.021).

CONCLUSIONS The results of this study suggest that BMI may differentially affect functional outcomes after aSAH, depending on treatment modality. These findings may aid in treatment selection for patients with aSAH.

 

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Radiation-Induced Changes After Stereotactic Radiosurgery for Brain Arteriovenous Malformations

Neurosurgery 83:365–376, 2018

Radiation-induced changes (RICs) are the most common complication of stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs), and they appear as perinidal T2-weighted hyperintensities on magnetic resonance imaging, with or without associated neurological symptoms.

OBJECTIVE: To determine the rates of RIC after AVM SRS and identify risk factors.

METHODS: A literature review was performed using PubMed and MEDLINE to identify studies reporting RIC in AVM patients treated with SRS. RICs were classified as radiologic (any neuroimaging evidence), symptomatic (any associated neurological deterioration, regardless of duration), and permanent (neurological decline without recovery). Baseline, treatment, and outcomes data were extracted for statistical analysis.

RESULTS: Based on pooled data from 51 studies, the overall rates of radiologic, symptomatic, and permanent RIC after AVMSRS were 35.5% (1143/3222 patients, 32 studies), 9.2% (499/5447 patients, 46 studies), and 3.8% (202/5272 patients, 39 studies), respectively. Radiologic RIC was significantly associated with lack of prior AVM rupture (odds ratio [OR] = 0.57; 95% confidence interval [CI]: 0.47-0.69; P < .001) and treatment with repeat SRS (OR = 6.19; 95% CI: 2.42-15.85; P < .001). Symptomatic RIC was significantly associated with deep AVM location (OR = 0.38; 95% CI: 0.21-0.67; P< .001).

CONCLUSION: Approximately 1 in 3 patients with AVMs treated with SRS develop radiologically evident RIC, and of those with radiologic RIC, 1 in 4 develop neurological symptoms. Lack of prior AVM hemorrhage and repeat SRS are risk factors for radiologic RIC, and deep nidus location is a risk factor for symptomatic RIC.

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Favorable clinical outcome following surgical evacuation of deep-seated and lobar supratentorial intracerebral hemorrhage

Acta Neurochirurgica (2018) 160:1737–1747

In spontaneous supratentorial intracerebral hemorrhage (ICH), the role of surgical treatment remains controversial, particularly in deep-seated ICHs. We hypothesized that early mortality and long-term functional outcome differ between patients with surgically treated lobar and deep-seated ICH.

Method Patients who underwent craniotomy for ICH evacuation from 2009 to 2015 were retrospectively evaluated and categorized into two subgroups: lobar and deep-seated ICH. The modified Rankin Scale (mRS) was used to evaluate long-term functional outcome.

Result Of the 123 patients operated for ICH, 49.6%(n = 61) had lobar and 50.4%(n = 62) deep-seated ICH. At long-term followup (mean 4.2 years), 25 patients (20.3%) were dead, while 51.0% of survivors had a favorable outcome (mRS score ≤ 3). Overall mortality was 13.0% at 30 days and 17.9% at 6 months post-ictus, not influenced by ICH location. Mortality was higher in patients ≥ 65 years old (p = 0.020). The deep-seated group had higher incidence and extent of intraventricular extension, younger age (52.6 ± 9.0 years vs. 58.5 ± 9.8 years; p < 0.05), more frequently pupillary abnormalities, and longer neurocritical care stay (p < 0.05). The proportion of patients with good outcome was 48.0% in deep-seated vs. 54.1% in lobar ICH (p = 0.552). In lobar ICH, independent predictors of long-term outcome were age, hemorrhage volume, preoperative level of consciousness, and pupillary reaction. In deep-seated ICHs, only high age correlated significantly with poor outcome.

Conclusions At long-term follow-up, most ICH survivors had a favorable clinical outcome. Neither mortality nor long-term functional outcome differed between patients operated for lobar or deep-seated ICH. A combination of surgery and neurocritical care can result in favorable clinical outcome, regardless of ICH location.

 

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Idiopathic intracranial hypertension: 120-day clinical, radiological, and manometric outcomes after stent insertion into the dural venous sinus

J Neurosurg 129:723–731, 2018

Idiopathic intracranial hypertension (IIH) is commonly associated with venous sinus stenosis. In recent years, transvenous dural venous sinus stent (DVSS) insertion has emerged as a potential therapy for resistant cases. However, there remains considerable uncertainty over the safety and efficacy of this procedure, in particular the incidence of intraprocedural and delayed complications and in the longevity of sinus patency, pressure gradient obliteration, and therapeutic clinical outcome. The aim of this study was to determine clinical, radiological, and manometric outcomes at 3–4 months after DVSS in this treated IIH cohort.

METHODS Clinical, radiographic, and manometric data before and 3–4 months after DVSS were reviewed in this single-center case series. All venographic and manometric procedures were performed under local anesthesia with the patient supine.

RESULTS Forty-one patients underwent DVSS venography/manometry within 120 days. Sinus pressure reduction of between 11 and 15 mm Hg was achieved 3–4 months after DVSS compared with pre-stent baseline, regardless of whether the procedure was primary or secondary (after shunt surgery). Radiographic obliteration of anatomical stenosis correlating with reduction in pressure gradients was observed. The complication rate after DVSS was 4.9% and stent survival was 87.8% at 120 days. At least 20% of patients developed restenosis following DVSS and only 63.3% demonstrated an improvement or resolution of papilledema.

CONCLUSIONS Reduced venous sinus pressures were observed at 120 days after the procedure. DVSS showed lower complication rates than shunts, but the clinical outcome data were less convincing. To definitively compare the outcomes between DVSS and shunts in IIH, a randomized prospective study is needed.

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Subarachnoid hemorrhage after surgical treatment of unruptured intracranial aneurysms

J Neurosurg 129:490–497, 2018

Only a few previous studies have investigated subarachnoid hemorrhage (SAH) after surgical treatment in patients with unruptured intracranial aneurysms (UIAs). Given the improvement in long-term outcomes of embolization, more extensive data are needed concerning the true rupture rates after microsurgery in order to provide reliable information for treatment decisions. The purpose of this study was to investigate the incidence of and risk factors for postoperative SAH in patients with surgically treated UIAs.

METHODS Data from 702 consecutive patients harboring 852 surgically treated UIAs were evaluated. Surgical treatments included neck clipping (complete or incomplete), coating/wrapping, trapping, proximal occlusion, and bypass surgery. Clippable UIAs were defined as UIAs treated by complete neck clipping. The annual incidence of postoperative SAH and risk factors for SAH were studied using Kaplan-Meier survival analysis and Cox proportional hazards regression models.

RESULTS The patients’ median age was 64 years (interquartile range [IQR] 56–71 years). Of 852 UIAs, 767 were clippable and 85 were not. The mean duration of follow-up was 731 days (SD 380 days). During 1708 aneurysm years, there were 4 episodes of SAH, giving an overall average annual incidence rate of 0.23% (95% CI 0.12%–0.59%) and an average annual incidence rate of 0.065% (95% CI 0.0017%–0.37%) for clippable UIAs (1 episode of SAH, 1552 aneurysmyears). Basilar artery location (adjusted hazard ratio [HR] 23, 95% CI 2.0–255, p = 0.0012) and unclippable UIA status (adjusted HR 15, 95% CI 1.1–215, p = 0.046) were significantly related to postoperative SAH. An excellent outcome (modified Rankin Scale score of 0 or 1) was achieved in 816 (95.7%) of 852 cases overall and in 748 (98%) of 767 clippable UIAs at 12 months.

CONCLUSIONS In this large case series, microsurgical treatment of UIAs was found to be safe and effective. Aneurysm location and unclippable morphologies were related to postoperative SAH in patients with surgically treated UIAs.

 

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Development of a statistical model for discrimination of rupture status in posterior communicating artery aneurysms

Acta Neurochirurgica (2018) 160:1643–1652

Intracranial aneurysms at the posterior communicating artery (PCOM) are known to have high rupture rates compared to other locations. We developed and internally validated a statistical model discriminating between ruptured and unruptured PCOM aneurysms based on hemodynamic and geometric parameters, angio-architectures, and patient age with the objective of its future use for aneurysm risk assessment.

Methods A total of 289 PCOM aneurysms in 272 patients modeled with image-based computational fluid dynamics (CFD) were used to construct statistical models using logistic group lasso regression. These models were evaluated with respect to discrimination power and goodness of fit using tenfold nested cross-validation and a split-sample approach to mimic external validation.

Results The final model retained maximum and minimum wall shear stress (WSS), mean parent artery WSS, maximum and minimum oscillatory shear index, shear concentration index, and aneurysm peak flow velocity, along with aneurysm height and width, bulge location, non-sphericity index, mean Gaussian curvature, angio-architecture type, and patient age. The corresponding area under the curve (AUC) was 0.8359. When omitting data from each of the three largest contributing hospitals in turn, and applying the corresponding model on the left-out data, the AUCs were 0.7507, 0.7081, and 0.5842, respectively.

Conclusions Statistical models based on a combination of patient age, angio-architecture, hemodynamics, and geometric characteristics can discriminate between ruptured and unruptured PCOM aneurysms with an AUC of 84%. It is important to include data from different hospitals to create models of aneurysm rupture that are valid across hospital populations.

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Indocyanine Green Videoangiography in Aneurysm Surgery: Systematic Review and Meta-Analysis

Neurosurgery, 83 (2): 166–180

Although digital subtraction angiography (DSA) may be considered the gold standard for intraoperative vascular imaging, many neurosurgical centers rely only on indocyanine green videoangiography (ICG-VA) for the evaluation of clipping accuracy. Many studies have compared the results of ICG-VA with those of intraoperative DSA; however, a systematic review summarizing these results is still lacking.
OBJECTIVE
To analyze the literature in order to evaluate ICG-VA accuracy in the identification of aneurysm remnants and vessel stenosis after aneurysm clipping.
METHODS
We performed a systematic literature review of ICG-VA accuracy during aneurysm clipping as compared to microscopic visual observation (primary endpoint 1) and DSA (primary endpoint 2). Quality of studies was assessed with the QUADAS-2 tool. Meta-analysis was performed using a random effects model.
RESULTS
The initial PubMed search resulted in 2871 records from January 2003 to April 2016; of these, 20 articles were eligible for primary endpoint 1 and 11 for primary endpoint 2. The rate of mis-clippings that eluded microscopic visual observation and were identified at ICG-VA was 6.1% (95% CI: 4.2-8.2), and the rate of mis-clippings that eluded ICG-VA and were identified at DSA was 4.5% (95% CI: 1.8-8.3).

CONCLUSION
Because a proportion of mis-clippings cannot be identified with ICG-VA, this technique should still be considered complementary rather than a replacement to DSA during aneurysm surgery. Incorporating other intraoperative tools, such as flowmetry or electrophysiological monitoring, can obviate the need for intraoperative DSA for the identification of vessel stenosis. Nevertheless, DSA likely remains the best tool for the detection of aneurysm remnants.

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Microsurgical Clipping of Ruptured Anterosuperior-Projecting Anterior Communicating Artery Aneurysms: How We Do It

World Neurosurg. (2018) 116:133-135

In anterosuperior-projecting anterior communicating artery (ACoA) aneurysms, the aneurysm dome usually adheres to 1 or both proximal A2 segments, which may present technical difficulties. This video demonstrates microsurgical clipping of a ruptured anterosuperior-projecting ACoA aneurysm. A 52-year-old male presented with a Hunt-Hess grade II subarachnoid hemorrhage. Computed tomography showed subarachnoid hemorrhage in the basal cisterns and sylvian and interhemispheric fissures. Angiography demonstrated a wide-necked ACoA aneurysm projecting anterosuperiorly. Considering the risk of recurrence, the patient decided to accept surgical treatment.

The patient was positioned supine, and the aneurysm was exposed via the lateral supraorbital approach. The carotid cistern and optic cistern were opened to release cerebrospinal fluid and achieve adequate brain relaxation. A subpial resection of a small portion of the gyrus rectus was performed to visualize the ipsilateral A2, recurrent artery of Heubner, and base of the aneurysm. A plane was dissected between the anterior aspect of both the A2 segment and posterior aspect of the aneurysm. A straight clip was placed parallel to the ACoA to completely obliterate the aneurysm. Postoperative angiography confirmed complete obliteration of the aneurysm. The patient recovered well without any complications.

Successful treatment requires preoperative surgical planning, precise dissection, and preservation of critical structures. With adherence to these general principles, these aneurysms can be treated safely and effectively.

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Cranial nerve deficits in giant cavernous carotid aneurysms and their relation to aneurysm morphology and location

Acta Neurochirurgica (2018) 160:1653–1660

Giant cavernous carotid aneurysms (GCCAs) usually exert substantial mass effect on adjacent intracavernous cranial nerves. Since predictors of cranial nerve deficits (CNDs) in patients with GCCA are unknown, we designed a study to identify associations between CND and GCCA morphology and the location of mass effect.

Methods This study was based on data from the prospective clinical and imaging databases of the Giant Intracranial Aneurysm Registry. We used magnetic resonance imaging and digital subtraction angiography to examine GCCA volume, presence of partial thrombosis (PT), GCCA origins, and the location of mass effect. We also documented whether CND was present.

Results We included 36 GCCA in 34 patients, which had been entered into the registry by eight participating centers between January 2009 and March 2016. The prevalence of CND was 69.4%, with one CND in 41.7% and more than one in 27.5%. The prevalence of PT was 33.3%. The aneurysm origin was most frequently located at the anterior genu (52.8%). The prevalence of CND did not differ between aneurysm origins (p = 0.29). Intracavernous mass effect was lateral in 58.3%, mixed medial/lateral in 27.8%, and purely medial in 13.9%. CND occurred significantly more often in GCCA with lateral (81.0%) or mixed medial/lateral (70.0%)mass effect than in GCCA with medial mass effect (20.0%; p = 0.03). After adjusting our data for the effects of the location of mass effect, we found no association between the prevalence of CND and aneurysm volume (odds ratio (OR) 1.30 (0.98–1.71); p = 0.07), the occurrence of PT (OR 0.64 (0.07–5.73); p = 0.69), or patient age (OR 1.02 (95% CI 0.95–1.09); p = 0.59).

Conclusions Distinguishing between medial versus lateral location of mass effect may be more helpful than measuring aneurysm volumes or examining aneurysm thrombosis in understanding why some patients with GCCA present with CND while others do not.

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Minimally Invasive Surgery is Superior to Conventional Craniotomy in Patients with Spontaneous Supratentorial Intracerebral Hemorrhage: A Systematic Review and Meta-Analysis

World Neurosurg. (2018) 115:266-273

Outcomes of minimally invasive surgery (MIS) versus conventional craniotomy (CC) for patients with spontaneous supratentorial intracerebral hemorrhage (SICH) have not been compared previously. We reviewed the current evidence regarding the safety and efficacy of MIS compared with CC in patients with SICH.

METHODS: We conducted a meta-analysis of studies comparing MIS and CC in patients with computed tomography confirmed SICH published between January 2000 and April 2018 in MEDLINE, Embase, and the Cochrane Controlled Trials Register based on PRISMA inclusion and exclusion criteria. Binary outcomes comparisons between MIS and CC were described using odds ratios (ORs).

RESULTS: Five randomized controlled trials (RCTs) and 9 prospective controlled studies (non-RCTs), involving a total of 2466 patients, met our inclusion criteria. There was a statistically significant difference in mortality rate between MIS and CC (OR, 0.76; 95% confidence interval [CI], 0.60e0.97). MIS was associated with a lower rate of rebleeding (OR, 0.42; 95% CI, 0.28e0.64) and a higher rate of good recovery compared with CC (OR, 2.27; 95% CI, 1.34e3.83).

CONCLUSIONS: Patients with SICH may benefit more from MIS than CC. Our study could help clinicians optimize treatment strategies in SICH

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Total Hospital Costs and Length of Stay of Endovascular Coiling Versus Neurosurgical Clipping for Unruptured Intracranial Aneurysms: Systematic Review and Meta-Analysis

World Neurosurg. (2018) 115:393-399

OBJECTIVE: Comparison of feasibility and safety between endovascular
coiling versus neurosurgical clipping for the management of unruptured intracranial aneurysms (UIAs) has been incrementally reported. However, economic comparison has been rarely reported. This meta-analysis aims at qualitatively and quantitatively analyzing the difference of hospital costs and length of stay between endovascular versus neurosurgical treatment in UIA.

METHODS: MEDLINE, the Cochrane database, EMBASE, and Web of Science
database were searched for cohort studies describing economic hospital cost or length of stay in patients with UIA. Two authors independently assessed study eligibility and rated quality using the Newcastle Ottawa Scale. Ravmen 5.2 was used to perform forest plot analysis.

RESULTS: Nine studies describing 24,856 UIAs treated with neurosurgical
clipping and 31,309 UIAs treated with endovascular coiling were included.
Meta-analysis revealed that the total hospital costs (THCs) were similar between coiling and clipping in UIA patients (standard mean difference
[SMD]: -0.33, 95% confidence interval: -0.68 to 0.02, f = 99%, P [ 0.07).
Subgroup analysis showed that THCs of coiling were significantly lower than
clipping in the United States but opposite in South Korea. One-year medical
costs of coiling were similar in both groups (SMD: -0.04, 95% CI: -0.08 to 0.00, f = 0%, P [ 0.07). In addition, the length of stay of coiling were significantly shorter than that of clipping (SMD: 0.69, 95% CI: 0.56e0.81, f = 95%, P < 0.001).

CONCLUSION: Generally, no significant difference in THCs and 1-year medical
costs between coiling versus clipping in UIAs was observed. However, the
length of stay of endovascular coiling was much shorter than neurosurgical
clipping and decreased over time.

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Pure arterial malformations

J Neurosurg 129:91–99, 2018

Over the last half century, there have been isolated case reports of purely arterial malformations. In this study, the authors report a consecutive series of patients with pure arterial malformations, emphasizing the clinical and radiological features of these lesions.

METHODS Pure arterial malformations were defined as dilated, overlapping, and tortuous arteries with a coil-like appearance and/or a mass of arterial loops without any associated venous component. Demographic characteristics of the patients, cardiovascular risk factors, presentation, radiological characteristics, and follow-up data were collected. Primary outcomes were new neurological symptoms including disability, stroke, and hemorrhage.

RESULTS Twelve patients meeting the criteria were identified. Ten patients were female (83.3%) and 2 were male (16.6%). Their mean age at diagnosis was 26.2 ± 11.6 years. The most common imaging indication was headache (7 patients [58.3%]). In 3 cases the pure arterial malformation involved the anterior cerebral arteries (25.0%); in 4 cases the posterior communicating artery/posterior cerebral artery (33.3%); in 2 cases the middle cerebral artery (16.6%); and in 1 case each, the superior cerebellar artery, basilar artery/anterior inferior cerebellar artery, and posterior inferior cerebellar artery. The mean maximum diameter of the malformations was 7.2 ± 5.0 mm (range 3–16 mm). Four lesions had focal aneurysms associated with the pure arterial malformation, and 5 were partially calcified. In no cases was there associated intracranial hemorrhage or infarction. One patient underwent treatment for the pure arterial malformation. All 12 patients had follow-up (mean 29 months, median 19 months), and there were no cases of disability, stroke, or hemorrhage.

CONCLUSIONS Pure arterial malformations are rare lesions that are often detected incidentally and probably have a benign natural history. These lesions can affect any of the intracranial arteries and are likely best managed conservatively.

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Cerebrovascular Imaging: Which Test is Best?

Neurosurgery 83:5–18, 2018

Optimal diagnosis and characterization of cerebrovascular disease requires selection of the appropriate imaging exam for each clinical situation.

In this review,we focus on intracranial arterial disease and discuss the techniques in current clinical use for imaging the blood vessel lumen and blood vessel wall, and for mapping cerebral hemodynamic impairment at the tissue level.

We then discuss specific strategies for imaging intracranial aneurysms, arteriovenous malformations, dural arterial venous fistulas, and arterial steno-occlusive disease.

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Accuracy in Identifying the Source of Subarachnoid Hemorrhage in the Setting of Multiple Intracranial Aneurysms

Neurosurgery 83:62–68, 2018

Subarachnoid hemorrhage cases with multiple cerebral aneurysms frequently demonstrate a hemorrhage pattern that does not definitively delineate the source aneurysm. In these cases, rupture site is ascertained from angiographic features of the aneurysm such as size, morphology, and location.

OBJECTIVE: To examine the frequency with which such features lead to misidentification of the ruptured aneurysm.

METHODS : Records of patients who underwent surgical clipping of a ruptured aneurysm at our institution between 2004 and 2014 and had multiple aneurysms were retrospectively reviewed. A blinded neuroendovascular surgeon provided the rupture source based on the initial head computed tomography scans and digital subtraction angiography images. Operative reports were then assessed to confirm or refute the imaging-based determination of the rupture source.

RESULTS: One hundred fifty-one patients had multiple aneurysms. Seventy-one patients had definitive hemorrhage patterns on initial computed tomography scans and 80 patients had nondefinitive hemorrhage patterns. Thirteen (16.2%) of the cases with nondefinitive hemorrhage patterns had discordance between the imaging-based determination of the rupture source and intraoperative findings of the true ruptured aneurysm, yielding an imperfect positive predictive value of 83.8%. Of all multiple aneurysm cases with subarachnoid hemorrhage treated by surgical or endovascular means at our institution, 4.3% (13 of 303) were misidentified.

CONCLUSION: Morphological features cannot reliably be used to determine rupture site in cases with nondefinitive subarachnoid hemorrhage patterns. Microsurgical clipping, confirming obliteration of the ruptured lesion, may be preferentially indicated in these patients unless, alternatively, all lesions can be contemporaneously and safely treatedwith endovascular embolization.

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Validation of the unruptured intracranial aneurysm treatment score.

J Neurosurg 129:100–106, 2018

The purpose of this study was to compare the unruptured intracranial aneurysm treatment score (UIATS) recommendations with the real-world experience in a quaternary academic medical center with a high volume of patients with unruptured intracranial aneurysms (UIAs).

METHODS All patients with UIAs evaluated during a 3-year period were included. All factors included in the UIATS were abstracted, and patients were scored using the UIATS. Patients were categorized in a contingency table assessing UIATS recommendation versus real-world treatment decision. The authors calculated the percentage of misclassification, sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve.

RESULTS A total of 221 consecutive patients with UIAs met the inclusion criteria: 69 (31%) patients underwent treatment and 152 (69%) did not. Fifty-nine (27%) patients had a UIATS between -2 and 2, which does not offer a treatment recommendation, leaving 162 (73%) patients with a UIATS treatment recommendation. The UIATS was significantly associated with treatment (p < 0.001); however, the sensitivity, specificity, and percentage of misclassification were 49%, 80%, and 28%, respectively. Notably, 51% of patients for whom treatment would be recommended by the UIATS did not undergo treatment in the real-world cohort and 20% of patients for whom conservative management would be recommended by UIATS had intervention. The area under the ROC curve was 0.646.

CONCLUSIONS Compared with the authors’ experience, the UIATS recommended overtreatment of UIAs. Although the UIATS could be used as a screening tool, individualized treatment recommendations based on consultation with a cerebrovascular specialist are necessary. Further validation with longitudinal data on rupture rates of UIAs is needed before widespread use.

 

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Contralateral posterior interhemispheric approach to deep medial parietooccipital vascular malformations

J Neurosurg 129:198–204, 2018

Deep medial parietooccipital arteriovenous malformations (AVMs) and cerebral cavernous malformations (CCMs) are traditionally resected through an ipsilateral posterior interhemispheric approach (IPIA), which creates a deep, perpendicular perspective with limited access to the lateral margins of the lesion. The contralateral posterior interhemispheric approach (CPIA) flips the positioning, with the midline positioned horizontally for retraction due to gravity, but with the AVM on the upper side and the approach from the contralateral, lower side. The aim of this paper was to analyze whether the perpendicular angle of attack that is used in IPIA would convert to a parallel angle of attack with the CPIA, with less retraction, improved working angles, and no significant increase in risk.

METHODS A retrospective review of pre- and postoperative clinical and radiographic data was performed in 8 patients who underwent a CPIA.

RESULTS Three AVMs and 5 CCMs were resected using the CPIA, with an average nidus size of 2.3 cm and CCM diameter of 1.7 cm. All lesions were resected completely, as confirmed on postoperative catheter angiography or MRI. All patients had good neurological outcomes, with either stable or improved modified Rankin Scale scores at last follow-up.

CONCLUSIONS The CPIA is a safe alternative approach to the IPIA for deep medial parietooccipital vascular malformations that extend 2 cm or more off the midline. Contralaterality and retraction due to gravity optimize the interhemispheric corridor, the surgical trajectory to the lesion, and the visualization of the lateral margin, without resection or retraction of adjacent normal cortex. Although the falx is a physical barrier to accessing the lesion, it stabilizes the ipsilateral hemisphere while gravity delivers the dissected lesion through the transfalcine window. Patient positioning, CSF drainage, venous preservation, and meticulous dissection of the deep margins are critical to the safety of this approach.

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Characteristics of Unruptured Compared to Ruptured Intracranial Aneurysms: A Multicenter Case–Control Study

Neurosurgery 83:43–52, 2018

Only a minority of intracranial aneurysms rupture to cause subarachnoid hemorrhage.

OBJECTIVE: To test the hypothesis that unruptured aneurysms have different characteristics and risk factor profiles compared to ruptured aneurysms.

METHODS: We recruited patients with unruptured aneurysms or aneurysmal subarachnoid hemorrhages at 22 UK hospitals between 2011 and 2014. Demographic, clinical, and imaging data were collected using standardized case report forms. We compared risk factors using multivariable logistic regression.

RESULTS: A total of 2334 patients (1729 with aneurysmal subarachnoid hemorrhage, 605 with unruptured aneurysms) were included (mean age 54.22 yr). In multivariable analyses, the following variables were independently associated with rupture status: black ethnicity (odds ratio [OR] 2.42; 95% confidence interval [CI] 1.29-4.56, compared to white) and aneurysm location (anterior cerebral artery/anterior communicating artery [OR 3.21; 95% CI 2.34-4.40], posterior communicating artery [OR 3.92; 95% CI 2.67-5.74], or posterior circulation [OR 3.12; 95% CI 2.08-4.70], compared to middle cerebral artery). The following variables were inversely associated with rupture status: antihypertensive medication (OR 0.65; 95% CI 0.49-0.84), hypercholesterolemia (0.64 OR; 95% CI 0.48-0.85), aspirin use (OR 0.28; 95% CI 0.20-0.40), internal carotid artery location (OR 0.53; 95% CI 0.38-0.75), and aneurysm size (per mm increase; OR 0.76; 95% CI 0.69-0.84).

CONCLUSION: We show substantial differences in patient and aneurysm characteristics between ruptured and unruptured aneurysms. These findings support the hypothesis that different pathological mechanisms are involved in the formation of ruptured aneurysms and incidentally detected unruptured aneurysms. The potential protective effect of aspirin might justify randomized prevention trials in patients with unruptured aneurysms.

K

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Optic neuropathy after anterior communicating artery aneurysm clipping

J Neurosurg 128:1808–1812, 2018

Brain shifts following microsurgical clip ligation of anterior communicating artery (ACoA) aneurysms can lead to mechanical compression of the optic nerve by the clip. Recognition of this condition and early repositioning of clips can lead to reversal of vision loss.

The authors identified 3 patients with an afferent pupillary defect following microsurgical clipping of ACoA aneurysms. Different treatment options were used for each patient. All patients underwent reexploration, and the aneurysm clips were repositioned to prevent clip-related compression of the optic nerve. Near-complete restoration of vision was achieved at the last clinic follow-up visit in all 3 patients.

Clip ligation of ACoA aneurysms has the potential to cause clip-related compression of the optic nerve. Postoperative visual examination is of utmost importance, and if any changes are discovered, reexploration should be considered as repositioning of the clips may lead to resolution of visual deterioration.

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Cost of coils for intracranial aneurysms: clinical decision analysis for implementation of a capitation model

J Neurosurg 128:1792–1798, 2018

The price of coils used for intracranial aneurysm embolization has continued to rise despite an increase in competition in the marketplace. Coils on the US market range in list price from $500 to $3000. The purpose of this study was to investigate potential cost savings with the use of a price capitation model.

METHODS The authors built a clinical decision analytical tree and compared their institution’s current expenditure on endovascular coils to the costs if a capped-price model were implemented. They retrospectively reviewed coil and cost data for 148 patients who underwent coil embolization from January 2015 through September 2016. Data on the length and number of coils used in all patients were collected and analyzed. The probabilities of a treated aneurysm being ≤/> 10 mm in maximum dimension, the total number of coils used for a case being ≤/> 5, and the total length of coils used for a case being ≤/> 50 cm were calculated, as was the mean cost of the currently used coils for all possible combinations of events with these probabilities. Using the same probabilities, the authors calculated the expected value of the capped-price strategy in comparison with the current one. They also conducted multiple 1-way sensitivity analyses by applying plausible ranges to the probabilities and cost variables. The robustness of the results was confirmed by applying individual distributions to all studied variables and conducting probabilistic sensitivity analysis.

RESULTS Ninety-five (64%) of 148 patients presented with a rupture, and 53 (36%) were treated on an elective basis. The mean aneurysm size was 6.7 mm. A total of 1061 coils were used from a total of 4 different providers. Companies A (72%) and B (16%) accounted for the major share of coil consumption. The mean number of coils per case was 7.3. The mean cost per case (for all coils) was $10,434. The median total length of coils used, for all coils, was 42 cm. The calculated probability of treating an aneurysm less than 10 mm in maximum dimension was 0.83, for using 5 coils or fewer per case it was 0.42, and for coil length of 50 cm or less it was 0.89. The expected cost per case with the capped policy was calculated to be $4000, a cost savings of $6564 in comparison with using the price of Company A. Multiple 1-way sensitivity analyses revealed that the capped policy was cost saving if its cost was less than $10,500. In probabilistic sensitivity analyses, the lowest cost difference between current and capped policies was $2750.

CONCLUSIONS In comparison with the cost of coils from the authors’ current provider, their decision model and probabilistic sensitivity analysis predicted a minimum $407,000 to a maximum $1,799,976 cost savings in 148 cases by adapting the capped-price policy for coils.

 

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