Predictors of neurological outcomes in patients with poor Glasgow Coma Scale scores 1 week after aneurysmal subarachnoid hemorrhage.

BACKGROUND: This study assessed neurological outcomes and variables associated with favorable outcomes in aSAH patients with low functional status (Glasgow Coma Scale [GCS] score ≤8) on postbleed day 7 (PBD7). METHODS: A retrospective analysis was conducted of all patients in the Barrow Ruptured Aneurysm Trial (January 1, 2014-July 31, 2019) treated for a ruptured aneurysm and who had a GCS score ≤8 on PBD7. The primary outcome was a favorable neurological outcome (modified Rankin Scale score ≤2) at last follow-up. RESULTS: Of 312 patients, 63 had low GCS scores at PBD7. These patients had a significantly greater proportion of poor Hunt and Hess scale grades (≥4) (44/63 [70%] vs 49/249 [19.7%], P < 0.001) and poor Fisher grades (grade=4) (58/63 [92%] vs 174/249 [69.9%], P < 0.001) compared to patients who did not have low GCS scores on PBD7, but no differences were found in age, sex, anterior location, aneurysm size, or type of treatment. Of the 63 patients, 7 (11%) experienced a favorable neurological outcome. On univariate analysis, none of the physical examination reflexes predicted a favorable neurological outcome. The middle cerebral artery aneurysm territory was the only significant predictor of a favorable neurological outcome by multivariate analysis (odds ratio, 10.8; 95% confidence interval, 1.16-100], P = 0.04). CONCLUSIONS: This study yielded no significant physical examination findings that predict a favorable outcome in patients with GCS score ≤8 on PBD7. This finding may inform the decision of whether to prolong hospital management or arrange for end-of-life care.

A taxonomy for cerebellar cavernous malformations: subtypes of cerebellar lesions.

OBJECTIVE: An anatomical taxonomy has been established to guide surgical approach selection for resecting brainstem and deep and superficial cerebral cavernous malformations (CMs). The authors propose a novel taxonomy for cerebellar CMs, introduce 6 distinct neuroanatomical subtypes, and assess their clinical outcomes. METHODS: This bi-institutional, 2-surgeon cohort study included 143 cerebellar CMs that were microsurgically treated over a 25-year period. The proposed taxonomy classifies cerebellar CMs into 6 subtypes on the basis of anatomical location as identified on preoperative MR imaging. Neurological outcomes were assessed using the modified Rankin Scale (mRS), and outcomes were compared among the subtypes, with favorable outcomes defined as mRS scores ≤ 2. RESULTS: A total of 143 cerebellar CMs were resected in 140 patients. The mean (SD) age was 42.3 (15.2) years; 86 (60%) of the cerebellar CMs were in women, and 57 (40%) were in men. Cerebellar subtypes were suboccipital (17%, 25/143); tentorial (9%, 13/143); petrosal (43%, 62/143); vermian (13%, 18/143); tonsillar (2%, 3/143); and deep nuclear (15%, 22/143). Overall, 78 of 143 (55%) cerebellar CMs presenting to a cerebellar surface were resected without tissue transgression, and the remaining CMs (65/143, 45%) required translobular or transsulcal approaches. Complete resection was achieved in 134 of 143 cases (94%). Favorable outcomes were achieved in 91% (129/141) of cases with follow-up at a mean (SD) follow-up duration of 37.4 (53.8) months. Relative outcomes were unchanged or improved relative to the preoperative baseline in 93% (131/141) of cases with follow-up, without differences between subtypes. CONCLUSIONS: Most cerebellar CMs are convexity lesions that do not require deep dissection. However, transsulcal and fissural approaches are used for those beneath the cerebellar surface to minimize tissue transgression and preserve associated function. Complete resection without any new deficit is accomplished in most patients. The proposed taxonomy for cerebellar CMs (suboccipital, tentorial, petrosal, vermian, tonsillar, and deep nuclear) guides the selection of craniotomy and approach to enhance patient safety and optimize neurological outcomes.

A single-cell atlas deconstructs heterogeneity across multiple models in murine traumatic brain injury and identifies novel cell-specific targets.

Traumatic brain injury (TBI) heterogeneity remains a critical barrier to translating therapies. Identifying final common pathways/molecular signatures that integrate this heterogeneity informs biomarker and therapeutic-target development. We present the first large-scale murine single-cell atlas of the transcriptomic response to TBI (334,376 cells) across clinically relevant models, sex, brain region, and time as a foundational step in molecularly deconstructing TBI heterogeneity. Results were unique to cell populations, injury models, sex, brain regions, and time, highlighting the importance of cell-level resolution. We identify cell-specific targets and previously unrecognized roles for microglial and ependymal subtypes. Ependymal-4 was a hub of neuroinflammatory signaling. A distinct microglial lineage shared features with disease-associated microglia at 24 h, with persistent gene-expression changes in microglia-4 even 6 months after contusional TBI, contrasting all other cell types that mostly returned to naive levels. Regional and sexual dimorphism were noted. CEREBRI, our searchable atlas (https://shiny.crc.pitt.edu/cerebri/), identifies previously unrecognized cell subtypes/molecular targets and is a leverageable platform for future efforts in TBI and other diseases with overlapping pathophysiology.

Transcirculation retrograde placement of a Pipeline embolization device for treatment of a vertebrobasilar junction aneurysm.

Transcirculation catheterization, also known as the retrograde approach, involves the navigation of a catheter or other endovascular device from one arterial circulation to the other (right to left, or anterior to posterior).1-4 We present a case of a complex vertebrobasilar junction aneurysm previously treated by bilateral vertebral artery deconstruction, precluding antegrade access (video 1). Following the creation of a protective occipital artery to posterior inferior cerebellar artery (PICA) bypass, the patient was treated with transcirculation placement of a Pipeline embolization device (PED).5-9 The right internal carotid artery was accessed with a guide catheter using a transradial approach. The microwire-microcatheter combination was then tracked through the right posterior communicating artery, down the basilar trunk, and to the left PICA. The PED was successfully deployed from the left vertebral artery to the mid-basilar artery. At 3-month follow-up, the aneurysm was completely obliterated. The nuances of transcirculation technique, especially for flow diversion, are discussed. (Used with permission from Barrow Neurological Institute, Phoenix, Arizona, USA.)neurintsurg;jnis-2023-021363v1/V1F1V1Video 1Transcirculation retrograde placement of a Pipeline embolization device for treatment of a vertebrobasilar junction aneurysm previously treated by bilateral vertebral artery deconstruction, precluding antegrade access.

Arteriovenous malformations in the cerebellopontine angle: assessment of the "backdoor resection" technique and microsurgical results in 38 patients.

OBJECTIVE: Posterior fossa arteriovenous malformations (AVMs) represent 7% to 15% of all intracranial AVMs and are associated with an increased risk of hemorrhage, morbidity, and mortality compared with supratentorial AVMs, thus prompting urgent and definitive treatment. Cerebellopontine angle (CPA) AVMs are a unique group of posterior fossa AVMs incorporating characteristics of brainstem and cerebellar lesions, which are particularly amenable to microsurgical resection. This study reports the clinical, radiological, operative, and outcome features of patients with CPA AVMs in a large cohort. METHODS: The authors conducted a single-surgeon, 2-institution retrospective cohort study of all consecutive patients with CPA AVMs treated with microsurgical resection during a 25-year period. RESULTS: CPA AVMs represented 22% (38 of 176) of all infratentorial AVMs resected by the senior author. Overall, 38 patients (22 [58%] male and 16 [42%] female) met the study inclusion criteria and were analyzed. Most patients presented with hemorrhage (n = 29, 76%). The median age at surgery was 56 (range 6-82) years. Subtypes included 22 (58%) petrosal cerebellar AVMs, 11 (29%) lateral pontine AVMs, and 5 (13%) AVMs involving both the brainstem and cerebellum. Most AVM niduses were small (< 3 cm; n = 35, 92%) and compact (n = 31, 82%). Fourteen (37%) patients harbored flow-related aneurysms. Twenty (53%) patients underwent preoperative embolization. Complete angiographic obliteration was achieved with microsurgery in 35 (92%) patients. Five (13%) patients with poor neurological conditions at presentation died before hospital discharge. Of the 7 (18%) patients with new postoperative neurological deficits, 5 had transient deficits. The median (interquartile range) follow-up was 1.7 (0.5-3.2) years; 32 (84%) patients were alive at last follow-up, and 30 (79%) had achieved a favorable neurological outcome (modified Rankin Scale [mRS] score 0-2). The only independent predictor of unfavorable postoperative outcome (mRS score 3-6) was the preoperative mRS score (p = 0.002). CONCLUSIONS: CPA AVMs are unique posterior fossa lesions, including petrosal cerebellar and lateral pontine AVMs. The "backdoor resection" technique provides a safe and efficient strategy with high obliteration rates and a low risk of treatment-related morbidity. Microsurgical resection should be considered the frontline treatment for most CPA AVMs, except for those with a significant diffuse brainstem component.

Assessing the Relationship between Surgical Timing and Postoperative Seizure Outcomes in Cavernoma-Related Epilepsy: A Single-Institution Retrospective Analysis of 63 Patients with a Review of the Literature.

Background: Patients with supratentorial cavernous malformations (SCMs) commonly present with seizures. First-line treatments for cavernoma-related epilepsy (CRE) include conservative management (antiepileptic drugs (AEDs)) and surgery. We compared seizure outcomes of CRE patients after early (≤6 months) vs. delayed (>6 months) surgery. Methods: We compared outcomes of CRE patients with SCMs surgically treated at our large-volume cerebrovascular center (1 January 2010-31 July 2020). Patients with 1 sporadic SCM and ≥1-year follow-up were included. Primary outcomes were International League Against Epilepsy (ILAE) class 1 seizure freedom and AED independence. Results: Of 63 CRE patients (26 women, 37 men; mean ± SD age, 36.1 ± 14.6 years), 48 (76%) vs. 15 (24%) underwent early (mean ± SD, 2.1 ± 1.7 months) vs. delayed (mean ± SD, 6.2 ± 7.1 years) surgery. Most (32 (67%)) with early surgery presented after 1 seizure; all with delayed surgery had ≥2 seizures. Seven (47%) with delayed surgery had drug-resistant epilepsy. At follow-up (mean ± SD, 5.4 ± 3.3 years), CRE patients with early surgery were more likely to have ILAE class 1 seizure freedom and AED independence than those with delayed surgery (92% (44/48) vs. 53% (8/15), p = 0.002; and 65% (31/48) vs. 33% (5/15), p = 0.03, respectively). Conclusions: Early CRE surgery demonstrated better seizure outcomes than delayed surgery. Multicenter prospective studies are needed to validate these findings.

Racial and Socioeconomic Status among a Patient Population Presenting with Aneurysmal Subarachnoid Hemorrhage versus Unruptured Intracranial Aneurysm: A Single-Center Study.

Racial and socioeconomic health disparities are well documented in the literature. This study examined patient demographics, including socioeconomic status (SES), among individuals presenting with aneurysmal subarachnoid hemorrhage (aSAH) and unruptured intracranial aneurysm (UIA) to identify factors associated with aSAH presentation. A retrospective assessment was conducted of all patients with aSAH and UIA who presented to a large-volume cerebrovascular center and underwent microsurgical treatment from January 2014 through July 2019. Race and ethnicity, insurance type, and SES data were collected for each patient. Comparative analysis of the aSAH and UIA groups was conducted. Logistic regression models were also employed to predict the likelihood of aSAH presentation based on demographic and socioeconomic factors. A total of 640 patients were included (aSAH group, 251; UIA group, 389). Significant associations were observed between race and ethnicity, SES, insurance type, and aneurysm rupture. Non-White race or ethnicity, lower SES, and having public or no insurance were associated with increased odds of aSAH presentation. The aSAH group had poorer functional outcomes and higher mortality rates than the UIA group. Patients who are non-White, have low SES, and have public or no insurance were disproportionately affected by aSAH, which is historically associated with poorer functional outcomes.

Posterior Interhemispheric-Transtentorial Approach for Resection of an Arteriovenous Malformation of the Superior Medullary Velum and Fourth Ventricle: 2-Dimensional Operative Video.

Brain arteriovenous malformations (AVMs) of the fourth ventricle represent a rare subtype associated with an aggressive natural course.1,2 In this case, a woman in her early 50s presented with dizziness. An AVM was diagnosed in the left superior cerebellar peduncle extending into the fourth ventricle. The AVM was supplied by superior cerebellar artery branches and classified as a Spetzler-Martin grade III and a Lawton-Young grade III, with a supplemented grade of 6.3,4 Being a single case report, institutional review board approval was not needed. Patient consent was obtained. The lesion was accessed through a torcular craniotomy and posterior interhemispheric-transtentorial approach, employing gravity to naturally retract the parietooccipital lobe.5-7 Dissection continued into the quadrigeminal and ambient cisterns, where the tentorium was incised parallelling the straight sinus to reach the superior vermis. Partial resection of the lingual and central lobules of the vermis facilitated access to the superior medullary velum. The superior cerebellar artery feeders were divided and followed to the superior cerebellar peduncle and through the superior medullary vellum. A vertical incision in the superior medullary velum facilitated entry into the fourth ventricle, where the AVM nidus was dissected circumferentially and resected en bloc. Intraoperative indocyanine green videoangiography and postoperative digital subtraction angiography confirmed complete obliteration of the AVM. After surgery, the patient experienced mild ataxia, but motor symptoms greatly improved during 3-month follow-up. This video illustrates resection of a complex fourth ventricular AVM through a posterior interhemispheric-transtentorial approach, highlighting pivotal considerations of patient positioning and approach selection to optimize treatment outcome for complex posterior fossa AVM resection.

Dolichoectatic Posterior Inferior Cerebellar Artery Aneurysm Treated With Excision and Posterior Inferior Cerebellar Artery Double Reimplantation Bypass: 2-Dimensional Operative Video.

Posterior inferior cerebellar artery (PICA) aneurysms account for 0.3% of all intracranial aneurysms, and they commonly present with a complex fusiform morphology that necessitates unique bypass strategies.1-5 An adolescent boy with a familial predisposition to aneurysmal subarachnoid hemorrhage was identified as harboring a fusiform aneurysm of the right distal PICA, characterized by 2 outflow branches. Our recommended treatment strategy involved a right far lateral craniotomy, followed by P1 PICA reanastomosis and P2 PICA reimplantation. Informed written consent was obtained. On exposure, the aneurysm was trapped, and the inflow and 2 outflow PICA branches were excised. Revascularization was established through a P1 PICA end-to-end reanastomosis using running continuous suturing techniques, followed by P2 PICA end-to-side reimplantation into a more distal portion of PICA. Subsequent indocyanine green videoangiography confirmed patency of the P2 PICA reimplantation; however, the initial P1 PICA reanastomosis was noted to be thrombosed. After several unsuccessful attempts to dissolve the thrombus, the decision was made to proceed with a P2 PICA side-to-side in situ reimplantation into the V4 segment of the vertebral artery. Indocyanine green videoangiography and postoperative digital subtraction angiography confirmed patency of the PICA double reimplantation bypass. The patient tolerated the procedure well and was discharged home at his neurological baseline. This video showcases the microsurgical treatment of a complex dolichoectatic, distal PICA aneurysm using a double reimplantation technique, in addition to highlighting bypass decision-making processes for managing complex PICA aneurysms.

Arteriovenous shunts of the cervical spine: patient demographics, presentation, patterns of high-risk venous drainage, and updated classification.

BACKGROUND: Intracranial dural arteriovenous (AV) fistula classifications focus on presence/absence of retrograde flow in the cortical veins of the brain as this angiographic finding portends a worse prognosis. However, prior categorization systems of AV shunts in the spine do not incorporate these features. We propose an updated classification for spinal shunting lesions that terms any shunting lesion with retrograde flow in any cortical vein of the brain or spinal cord medullary vein as "high risk". To present this classification, we analyzed our center's most recent experience with cervical spine shunting lesions. METHODS: The electronic medical record at our institution was reviewed to identify shunting lesions of the cervical spine and patient demographics/presentation. Comprehensive craniospinal digital subtraction angiograms were evaluated to classify shunt location, type (arteriovenous malformation (AVM) vs arteriovenous fistula (AVF)), and presence of high-risk venous drainage. RESULTS: Some 52 lesions were identified and categorized as pial/dural/epidural/paravertebral AVFs and intramedullary/extraspinal AVMs. Lesions were classified as high risk or not depending on the presence of retrograde flow into at least one vein that directly drains the spinal cord or brain. All patients who presented with either hemorrhage or infarct had underlying high-risk lesions. Additionally, 50% (17/34) of symptomatic patients with high-risk lesions presented with neurological extremity symptoms (OR=10.0, p=0.037) most of which fit a myelopathic pattern. CONCLUSION: We present an updated classification system for shunting lesions of the spine that focuses on high-risk retrograde flow to the brain or spine in addition to anatomical location in order to better inform patient management.

Microsurgical Resection of Brainstem Cavernous Malformations in Older Adults: A Multicenter, 30-Year Experience.

BACKGROUND AND OBJECTIVES: Microsurgical resection is the only curative intervention for symptomatic brainstem cavernous malformations (BSCMs), but the management of these lesions in older adults (≥65 years) is not well described. This study sought to address this gap by examining the safety and efficacy of BSCM resection in a cohort of older adults. METHODS: Records of patients who underwent BSCM resection over a 30-year period were reviewed retrospectively. Baseline characteristics and outcomes were compared between older (≥65 years) and younger (<65 years) patients. RESULTS: Of 550 patients with BSCM who met inclusion criteria, 41 (7.5%) were older than 65 years. Midbrain (43.9% vs 26.1%) and medullary lesions (19.5% vs 13.6%) were more common in the older cohort than in the younger cohort ( P = .01). Components of the Lawton BSCM grading system (ie, lesion size, crossing axial midpoint, developmental venous anomaly, and timing of hemorrhage) were not significantly different between cohorts ( P ≥ .11). Mean (SD) Elixhauser comorbidity score was significantly higher in older patients (1.86 [1.06]) than in younger patients (0.66 [0.95]; P < .001). Older patients were significantly more likely than younger patients to have poor outcomes at final follow-up (28.9% vs 13.8%, P = .01; mean follow-up duration, 28.7 [39.1] months). However, regarding relative neurological outcome (preoperative modified Rankin Scale to final modified Rankin Scale), rate of worsening was not significantly different between older and younger patients (23.7% vs 14.9%, P = .15). CONCLUSION: BSCMs can be safely resected in older patients, and when each patient's unique health status and life expectancy are taken into account, these patients can have outcomes similar to younger patients.

Sex differences in patients with and without high-risk factors associated with aneurysmal subarachnoid hemorrhage.

BACKGROUND: Controversy remains regarding the appropriate screening for intracranial aneurysms or for the treatment of aneurysmal subarachnoid hemorrhage (aSAH) for patients without known high-risk factors for rupture. This study aimed to assess how sex affects both aSAH presentation and outcomes for aSAH treatment. METHOD: A retrospective cohort study was conducted of all patients treated at a single institution for an aSAH during a 12-year period (August 1, 2007-July 31, 2019). An analysis of women with and without high-risk factors was performed, including a propensity adjustment for a poor neurologic outcome (modified Rankin Scale [mRS] score > 2) at follow-up. RESULTS: Data from 1014 patients were analyzed (69% [n = 703] women). Women were significantly older than men (mean ± SD, 56.6 ± 14.1 years vs 53.4 ± 14.2 years, p < 0.001). A significantly lower percentage of women than men had a history of tobacco use (36.6% [n = 257] vs 46% [n = 143], p = 0.005). A significantly higher percentage of women than men had no high-risk factors for aSAH (10% [n = 70] vs 5% [n = 16], p = 0.01). The percentage of women with an mRS score > 2 at the last follow-up was significantly lower among those without high-risk factors (34%, 24/70) versus those with high-risk factors (53%, 334/633) (p = 0.004). Subsequent propensity-adjusted analysis (adjusted for age, Hunt and Hess grade, and Fisher grade) found no statistically significant difference in the odds of a poor outcome for women with or without high-risk factors for aSAH (OR = 0.7, 95% CI = 0.4-1.2, p = 0.18). CONCLUSIONS: A higher percentage of women versus men with aSAH had no known high-risk factors for rupture, supporting more aggressive screening and management of women with unruptured aneurysms.

Hematologic and Inflammatory Predictors of Outcome in Patients with Brain Arteriovenous Malformations.

OBJECTIVE: This study investigated the prognostic value of admission blood counts for arteriovenous malformation (AVM) outcomes and compared admission blood counts for patients with ruptured and unruptured AVMs. METHODS: A retrospective analysis of patients who underwent surgical treatment for a ruptured cerebral AVM between February 1, 2014, and March 31, 2020, was conducted. The primary outcome was poor neurologic outcome, defined as a modified Rankin Scale score ≥2 in patients with unruptured AVMs or >2 in patients with ruptured AVMs. RESULTS: Of 235 included patients, 80 (34%) had ruptured AVMs. At admission, patients with ruptured AVMs had a significantly lower mean (SD) hemoglobin level (12.78 [2.07] g/dL vs. 13.71 [1.60] g/dL, P < 0.001), hematocrit (38.1% [5.9%] vs. 40.7% [4.6%], P < 0.001), lymphocyte count (16% [11%] vs. 26% [10%], P < 0.001), and absolute lymphocyte count (1.41 [0.72] × 103/µL vs. 1.79 [0.68] × 103/µL, P < 0.001), and they had a significantly higher mean (SD) white blood cell count (10.4 [3.8] × 103/µL vs. 7.6 [2.3] × 103/µL, P < 0.001), absolute neutrophil count (7.8 [3.8] × 103/µL vs. 5.0 [2.5] × 103/µL, P < 0.001), and neutrophil count (74% [14%] vs. 64% [13%], P < 0.001). Among patients with unruptured AVMs, white blood cell count ≥6.4 × 103/µL and absolute neutrophil count ≥3.4 × 103/µL were associated with a favorable neurologic outcome, whereas hemoglobin level ≥13.4 g/dL was associated with an unfavorable outcome. Among patients with ruptured AVMs, hypertension was associated with a 3-fold increase in odds of a poor neurologic outcome. CONCLUSIONS: Patients with ruptured and unruptured AVMs present with characteristic profiles of hematologic and inflammatory parameters evident in their admission blood work.

Modafinil Therapy and Mental Status Following Aneurysmal Subarachnoid Hemorrhage: Comprehensive Stroke Center Analysis.

BACKGROUND: Disorders of consciousness impair early recovery after aneurysmal subarachnoid hemorrhage (aSAH). Modafinil, a wakefulness-promoting agent, is efficacious for treating fatigue in stroke survivors, but data pertaining to its use in the acute setting are scarce. This study sought to assess the effects of modafinil use on mental status after aSAH. METHODS: Modafinil timing and dosage, neurological examination, intubation status, and physical and occupational therapy participation were documented. Repeated-measures paired tests were used for a before-after analysis of modafinil recipients. Propensity score matching (1:1 nearest neighbor) for modafinil and no-modafinil cohorts was used to compare outcomes. RESULTS: Modafinil (100-200 mg/day) was administered to 21% (88/422) of aSAH patients for a median (IQR) duration of 10.5 (4-16) days and initiated 14 (7-17) days after aSAH. Improvement in mentation (alertness, orientation, or Glasgow Coma Scale score) was documented in 87.5% (77/88) of modafinil recipients within 72 hours and 86.4% (76/88) at discharge. Of 37 intubated patients, 10 (27%) were extubated within 72 hours after modafinil initiation. Physical and occupational therapy teams noted increased alertness or participation in 47 of 56 modafinil patients (83.9%). After propensity score matching for baseline covariates, the modafinil cohort had a greater mean (SD) change in Glasgow Coma Scale score than the no-modafinil cohort at discharge (2.2 [4.0] vs. -0.2 [6.32], P = 0.003). CONCLUSIONS: A temporal relationship with improvement in mental status was noted for most patients administered modafinil after aSAH. These findings, a favorable adverse-effect profile, and implications for goals-of-care decisions favor a low threshold for modafinil initiation in aSAH patients in the acute-care setting.

Early Treatment of Ruptured Cerebral Arteriovenous Malformations: Analysis of Neurological Outcomes and Health Care Costs.

BACKGROUND: The timing of surgical resection is controversial when managing ruptured arteriovenous malformations (AVMs) and varies considerably among centers. OBJECTIVE: To retrospectively analyze clinical outcomes and hospital costs associated with delayed treatment in a ruptured cerebral AVM patient cohort. METHODS: Patients undergoing surgical treatment for a ruptured cerebral AVM (January 1, 2015-December 31, 2020) were retrospectively analyzed. Patients who underwent emergent treatment of a ruptured AVM because of acute herniation were excluded, as were those treated >180 days after rupture. Patients were stratified by the timing of surgical intervention relative to AVM rupture into early (postbleed days 1-20) and delayed (postbleed days 21-180) treatment cohorts. RESULTS: Eighty-seven patients were identified. The early treatment cohort comprised 75 (86%) patients. The mean (SD) length of time between AVM rupture and surgical resection was 5 (5) days in the early cohort and 73 (60) days in the delayed cohort ( P < .001). The cohorts did not differ with respect to patient demographics, AVM size, Spetzler-Martin grade, frequency of preoperative embolization, or severity of clinical presentation ( P ≥ .15). Follow-up neurological status was equivalent between the cohorts ( P = .65). The associated mean health care costs were higher in the delayed treatment cohort ($241 597 [$99 363]) than in the early treatment cohort ($133 989 [$110 947]) ( P = .02). After adjustment for length of stay, each day of delayed treatment increased cost by a mean of $2465 (95% CI = $967-$3964, P = .002). CONCLUSION: Early treatment of ruptured AVMs was associated with significantly lower health care costs than delayed treatment, but surgical and neurological outcomes were equivalent.

A Review of Preoperative Embolization Effectiveness in Patients With Arteriovenous Malformations.

BACKGROUND AND OBJECTIVES: Preoperative embolization of arteriovenous malformations (AVMs) remains controversial. This study sought to analyze the cost-effectiveness of preoperative embolization of AVMs. METHODS: Patients who underwent AVM resection at a single institute (January 1, 2015-December 31, 2020) were analyzed. Patients with preoperative embolization (embolization cohort) were compared with those without preoperative embolization (nonembolization cohort). Cost-effectiveness score (CE) was the primary outcome of interest and was determined by dividing the total 1-year cost by effectiveness, which was derived from a validated preoperative to last follow-up change in the modified Rankin Scale utility score. A lower CE signifies a more cost-effective treatment strategy. RESULTS: Of 188 patients, 88 (47%) underwent preoperative embolization. The mean (SD) total cost was higher in the embolization group than in the nonembolization group ($117 594 [$102 295] vs $84 348 [$82 326]; P < .001). The mean (SD) CE was higher in the embolization cohort ($336 476 [$1 303 842]) than in the nonembolization cohort ($100 237 [$246 255]; P < .001). Among patients with Spetzler-Martin (SM) grade I and II AVMs, the mean (SD) CE was higher in the embolization (n = 40) than in the nonembolization (n = 72) cohort ($164 950 [$348 286] vs $69 021 [$114 938]; P = .004). Among patients with SM grade III AVMs, the mean (SD) CE was lower in the embolization (n = 33) than in the nonembolization (n = 25) cohort ($151 577 [$219 130] vs $189 195 [$446 335]; P = .006). The mean (SD) CE was not significantly different between cohorts among patients with higher-grade AVMs (embolization cohort [n = 3] vs nonembolization cohort [n = 15]: $503 639 [$776 492] vs $2 048 419 [$4 794 758]; P = .49). The mean CE for embolized SM grade III aneurysms was nonsignificant in the ruptured group; however, for the unruptured group, CE was significantly higher in the embolization cohort (n = 26; $160 871 [$240 535]) relative to the nonembolization cohort (n = 15; $108 152 [$166 446]) ( P = .006). CONCLUSION: Preoperative embolization was cost-effective for patients with SM grade III AVMs but not for patients with lower-grade AVMs.