Tag: Hemorrhage

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Comparative Analysis of Efficacy and Safety of Frame-Based, Frameless, and Robot-Assisted Stereotactic Brain Biopsies: A Systematic Review and Meta-Analysis

Operative Neurosurgery 28:749–761, 2025

This systematic review and meta-analysis compares frame-based, frameless, and robot-assisted stereotactic brain biopsies. Robot-assisted biopsies demonstrated non-inferior diagnostic yield and safety compared to traditional methods, with shorter operative times. Complication and mortality rates were similar across all techniques, supporting robot-assisted biopsy as an effective alternative.

• Frame-based stereotactic brain biopsy has been the gold standard for high diagnostic yield and safety, especially for complex or deep-seated lesions.

• Frameless neuronavigation and robot-assisted techniques have emerged as alternatives over the past decade.

• Meta-analysis included 92 studies: 9801 frame-based, 2665 robot-assisted, and 1862 frameless cases.

• Pooled diagnostic yields: robot-assisted 97%, frame-based 95%, frameless 94%; robot-assisted was not inferior.

• Complication and mortality rates were low and similar across all methods.

• Robot-assisted procedures had significantly shorter total operative times (mean 76.6 min) compared to frame-based (132.7 min) and frameless (97.3 min).

• Diagnostic yield for brainstem lesions was comparable between robot-assisted and frame-based approaches.

• Robot-assisted biopsy may offer workflow, comfort, and efficiency advantages, especially for certain patient groups.

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Natural history, management, and outcomes of cerebellar cavernous malformations: A retrospective study of 130 patients

Neurosurgical Review (2025) 48:381

This study on cerebellar cavernous malformations (CMs) examines their natural history, management, and outcomes. It concludes that conservative management is generally effective for incidental lesions, while surgery is recommended for symptomatic cases, especially in accessible regions, due to the associated hemorrhage risks.

• This study investigates cerebellar cavernous malformations (CMs), focusing on natural history, management, and outcomes in 130 patients from 1990 to 2023.

• Hemorrhage risk for incidental lesions is 1.19%, while rehemorrhage risk for initially hemorrhagic lesions is 8.35%.

• Conservative management is recommended for incidental lesions, with surgery reserved for symptomatic, accessible cases.

• Surgery was performed on 31 patients, primarily for hemorrhage or cerebellar symptoms, with postoperative complications in three patients.

• Lesion location and size significantly influence hemorrhage risk and clinical outcomes, with eloquent regions posing higher risks.

• Long-term outcomes were generally favorable, with most patients experiencing improved or stable functional status.

• Psychological support is important due to potential cognitive and emotional impacts associated with cerebellar dysfunction.

• The study emphasizes the need for risk stratification based on lesion size and subregional anatomy within the cerebellum.

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Natural history and management outcomes of patients with ruptured Spetzler-Martin grade IV and V brain arteriovenous malformations

J Neurosurg 142:667–675, 2025

Study Objective: To explore the natural history and management outcomes of patients with ruptured Spetzler-Martin grade IV and V brain arteriovenous malformations (bAVMs).

• Patient Selection: The study involved 84 patients with ruptured high-grade bAVMs, identified from a database spanning 1990 to 2020.

• Hemorrhagic Risk: Annual hemorrhagic risk was 2.68% for cortical bAVMs and 8.37% for deep-seated bAVMs during natural history.

• Treatment Outcomes: Surgery reduced hemorrhagic risk significantly in cortical bAVMs, while radiosurgery was effective for deep-seated bAVMs. Embolization alone increased hemorrhagic risk.

• Predictors of Success: Surgery and radiosurgery were significant predictors of bAVM obliteration for cortical and deep-seated bAVMs, respectively.

• Management Strategies: Conservative management was compared to surgical interventions, showing similar functional outcomes but differing in obliteration rates.

• Conclusion: Surgery and radiosurgery may be viable options for certain patients, while embolization alone should be avoided

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Risk for Brain Arteriovenous Malformation Rupture During Pregnancy and Puerperium

Neurosurgery 93:918–923, 2023

The hemorrhage risk of unruptured and untreated cerebral arteriovenous malformations (AVMs) has been shown to be higher for female patients than male patients in their child bearing ages. Although it has been neurosurgical practice to advise female patients in their childbearing ages to postpone pregnancy until proven AVM obliteration, there is no literature consensus regarding this potential hemorrhage risk increase.

OBJECTIVE: To accurately quantify the risk increase for AVM hemorrhage during pregnancy.

METHODS: This study is based on data from previous publications, consisting of known age at the first AVM hemorrhage in 3425 patients. The risk increase during pregnancy could be calculated from the difference in age distribution for the first AVM hemorrhage between male patients and female patients, taking the average pregnancy time per female into account. A comparison was also made with data for all hospital discharges (13751) in Germany 2008 to 2018 with the diagnosis brain AVM.

RESULTS: The average pregnancy and puerperium time was 1.54 years per female in the patient population, which was used to determine the annual AVM hemorrhage risk during pregnancy to be around 9%. The increased risk during pregnancy was further evidenced by analysis of a subgroup of 105 female patients, for which pregnancy status at the time of hemorrhage was known.

CONCLUSION: The quantified annual risk for AVM hemorrhage during pregnancy is about 3 times higher than that of male patients at corresponding age. This provides an important basis for advising female patients with patent AVMs about the increased risk for hemorrhage that a pregnancy would entail.

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One-Insertion Stereotactic Brain Biopsy Using In Vivo Optical Guidance

Operative Neurosurgery 25:176–182, 2023

Stereotactic neurosurgical brain biopsies are afflicted with risks of inconclusive results and hemorrhage. Such complications can necessitate repeated trajectories and prolong surgical time.

OBJECTIVE: To develop and introduce a 1-insertion stereotactic biopsy kit with direct intraoperative optical feedback and to evaluate its applicability in 3 clinical cases.

METHODS: An in-house forward-looking probe with optical fibers was designed to fit the outer cannula of a side-cutting biopsy kit. A small aperture was made at the tip of the outer cannula and the edges aligned with the optical probe inside. Stereotactic biopsies were performed using the Leksell Stereotactic System. Optical signals were measured in millimeter steps along the preplanned trajectory during the insertion. At the region with the highest 5-aminolevulinic acid (5-ALA)induced fluorescence, the probe was replaced by the inner cannula, and tissue samples were taken. The waiting time for pathology diagnosis was noted.

RESULTS: Measurements took 5 to 10 minutes, and the surgeon received direct visual feedback of intraoperative 5-ALA fluorescence, microcirculation, and tissue gray-whiteness. The 5-ALA fluorescence corroborated with the pathological findings which had waiting times of 45, 50, and 75 minutes. Because only 1 trajectory was required and the patient could be prepared for the end of surgery immediately after sampling, this shortened the total surgical time. CONCLUSION: A 1-insertion stereotactic biopsy procedure with real-time optical guidance has been presented and successfully evaluated in 3 clinical cases. The method can be modified for frameless navigation and thus has great potential to improve safety and diagnostic yield for both frameless and frame-based neurosurgical biopsy procedures.

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Natural History of Spinal Cord Cavernous Malformations

Neurosurgery 90:390–398, 2022

The natural history of spinal cord cavernous malformations (SCCMs) remains relatively unclear.

OBJECTIVE: To investigate the natural history for hemorrhagic risks and neurological outcomes, as well as relevant predicting factors, of SCCMs.

METHODS: All patients between 2002 and 2019 with diagnosis of SCCMs were identified retrospectively. An observational study of patients with conservative management was performed to reveal the natural history of SCCMs.

RESULTS: We identified 305 patients in the full cohort, including 126 patients who were conservatively treated for at least 6 months (median observational period, 24.0 months). Forty-five hemorrhage events occurred during 527 person-years of follow-up, yielding an annual hemorrhage rate of 8.5% per person-year. The 1-, 2-, and 5-year cumulative risks of hemorrhage were 13.9%, 26.1%, and 35.1%, respectively. Prior hemorrhage (hazard ratio [HR] = 12.948, P = .012) and pediatric patients (HR = 2.841, P = .031) were independent predictors of hemorrhage in the long-term follow-up. Familial form (adjusted odds ratio [OR] = 30.695, P = .010) and subsequent hemorrhage events (adjusted OR = 16.333, P = .000) were independent risk factors for worsening of neurological function, and baseline neurological status (adjusted OR = 78.984, P = .000) and presence of subsequent hemorrhage (adjusted OR = 9.611, P = .001) were significantly associated with neurological outcomes.

CONCLUSION: The natural history of SCCMs varies. Baseline characteristics, such as pediatric patients, familial form, and baseline neurological status, as well as prior and subsequent hemorrhagic events, significantly affect the natural history of the SCCMs, which prompts a differentiated treatment strategy.

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Perioperative complications of deep brain stimulation among patients with advanced age

J Neurosurg 135:1421–1428, 2021

Deep brain stimulation (DBS) is an elective procedure that can dramatically enhance quality of life. Because DBS is not considered lifesaving, it is important that providers produce consistently good outcomes, and one factor they usually consider is patient age. While older age may be a relative contraindication for some elective surgeries, the progressive nature of movement disorders treated with DBS may suggest that older patients stand to benefit substantially from surgery. To better understand the risks of treating patients of advanced age with DBS, this study compares perioperative complication rates in patients ≥ 75 to those < 75 years old.

METHODS Patients undergoing DBS surgery for various indications by a single surgeon (May 2013–July 2019) were stratified into elderly (age ≥ 75 years) and younger (age < 75 years) cohorts. The risks of common perioperative complications and various outcome measures were compared between the two age groups using risk ratios (RRs) and 95% confidence intervals (CIs).

RESULTS A total of 861 patients were available for analysis: 179 (21%) were ≥ 75 years old and 682 (79%) were < 75 years old (p < 0.001). Patients ≥ 75 years old, compared with those < 75 years old, did not have significantly different RRs (95% CIs) of seizure (RR 0.4, 95% CI 0.1–3.3), cerebrovascular accident (RR 1.9, 95% CI 0.4–10.3), readmission within 90 days of discharge (RR 1.22, 95% CI 0.8–1.8), explantation due to infection (RR 2.5, 95% CI 0.4–15.1), or surgical revision (for lead, RR 2.5, 95% CI 0.4–15.1; for internal pulse generator, RR 3.8, 95% CI 0.2–61.7). Although the risk of postoperative intracranial bleeding was higher in the elderly group (6.1%) than in the younger group (3.1%), this difference was not statistically significant (p = 0.06). However, patients ≥ 75 years old did have significantly increased risk of altered mental status (RR 2.5, 95% CI 1.6–4.0), experiencing more than a 1-night stay (RR 1.7, 95% CI 1.4–2.0), and urinary retention (RR 2.3, 95% CI 1.2–4.2; p = 0.009).

CONCLUSIONS Although elderly patients had higher risks of certain outcome measures than younger patients, this study showed that elderly patients undergoing DBS for movement disorders did not have an increased risk of more serious complications, such as intracranial hemorrhage, infection, or readmission. Advanced age alone should not be considered a contraindication for DBS.

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Clinical and Angioarchitectural Features of Hemorrhagic Brain Arterio-Venous Malformations in Adults and Children

Neurosurgery 89:645–652, 2021

Hemorrhage from brain arteriovenous malformations (bAVMs) is estimated at 3% per annum. Features influencing risk of hemorrhage include perforator/ posterior circulation supply, associated aneurysms, and deep drainage. Children are more likely to present with bAVM bleeds.

OBJECTIVE: To analyze differences in bAVM angioarchitecture between children and adults and describe predictors of poor outcome.

METHODS: Data were collected from adult and pediatric tertiary referral hospitals. Demographic data, bleed location, treatment, and follow-up modified Rankin Scale (mRS) were collected. Angioarchitectural assessment included aneurysm presence, nidus morphology, perinidal angiogenesis, intranidal shunting, steal phenomenon, venous ectasia, venous stenosis, venous reflux, and pseudophlebitic pattern. Regression analyses conducted to determine predictors of mRS > 2.

RESULTS: A total of 270 adult and 135 pediatric ruptured bAVMswere assessed.Median age was 42 (adults) and 10.9 (children) yr. Intranidal aneurysms were more frequent in children (P = .012), whereas prenidal aneurysms were more common in adults (P < .01). Children demonstrated more perinidal angiogenesis (P = .04), whereas steal phenomenon was commoner in adults (P<.01). Venous ectasia (P<.01), reflux (P<.01), and pseudophlebitic pattern (P = .012) were more frequent in adults. Children had better outcome (mRS score ≤ 2) (P < .01). Older age (odds ratio [OR] = 1.02), eloquent location (OR = 2.5), multicompartmental hemorrhage (OR = 1.98), venous reflux (OR = 2.5), diffuse nidus (OR = 1.83), pseudophlebitic pattern (OR = 1.96), intranidal shunts (OR = 2), and no treatment (OR = 3.68) were significant predictors of mRS > 2.

CONCLUSION: Children aremore likely to have intranidal aneurysms and perinidal angiogenesis, whereas adults have more prenidal aneurysms, venous ectasia, corticovenous reflux, and pseudophlebitic pattern. Eloquent location, diffuse nidus, intranidal shunts, venous reflux, and pseudophlebitic pattern predict poorer outcome.

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Reconsidering an important subclass of high-risk dural arteriovenous fistulas for stereotactic radiosurgery

J Neurosurg 130:972–976, 2019

Aggressive dural arteriovenous fistulas (dAVFs) with cortical venous drainage (CVD) are known for their relatively high risk of recurrent neurological events or hemorrhage. However, recent natural history literature has indicated that nonaggressive dAVFs with CVD have a significantly lower prospective risk of hemorrhage. These nonaggressive dAVFs are typically diagnosed because of symptomatic headache, pulsatile tinnitus, or ocular symptoms, as in low-risk dAVFs. Therefore, the viability of stereotactic radiosurgery (SRS) as a treatment for this lesion subclass should be investigated.

METHODS The authors evaluated their institutional experience with SRS for dAVFs with CVD for the period from 1991 to 2016, assessing angiographic outcomes and posttreatment hemorrhage rates. They subsequently pooled their results with those published in the literature and stratified the results based on the mode of clinical presentation.

RESULTS In an institutional cohort of 42 dAVFs with CVD treated using SRS, there were no complications or hemorrhages after treatment in 19 patients with nonaggressive dAVFs, but there was 1 radiation-induced complication and 1 hemorrhage among the 23 patients with aggressive dAVFs. In pooling these cases with 155 additional cases from the literature, the authors found that the hemorrhage rate after SRS was significantly lower among the patients with nonaggressive dAVFs (0% vs 6.8%, p = 0.003). Similarly, the number of radiation-related complications was 0/124 in nonaggressive dAVF cases versus 6/73 in aggressive dAVF cases (p = 0.001). The annual rate of hemorrhage after SRS for aggressive fistulas was 3.0% over 164.5 patient-years, whereas none of the nonaggressive fistulas bled after radiosurgery over 279.4 patient-years of follow-up despite the presence of CVD.

CONCLUSIONS Cortical venous drainage is thought to be a significant risk factor in all dAVFs. In the institutional experience described here, SRS proved to be a low-risk strategy associated with a very low risk of subsequent hemorrhage or radiation-related complications in nonaggressive dAVFs with CVD.

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Stereotactic radiosurgery alone or combined with embolization for brain arteriovenous malformations

J Neurosurg 128:1338–1348, 2018

Embolization of brain arteriovenous malformations (AVMs) prior to stereotactic radiosurgery (SRS) has been reported to negatively affect obliteration rates. The goal of this systematic review and meta-analysis was to compare the outcomes of AVMs treated with embolization plus SRS (E+SRS group) and those of AVMs treated with SRS alone (SRS group).

METHODS A literature review was performed using PubMed to identify studies with 10 or more AVM patients and obliteration data for both E+SRS and SRS groups. A meta-analysis was performed to compare obliteration rates between the E+SRS and SRS groups.

RESULTS Twelve articles comprising 1716 patients were eligible for analysis. Among the patients with radiological follow-up data, complete obliteration was achieved in 48.4% of patients (330/681) in the E+SRS group compared with 62.7% of patients (613/978) in the SRS group. A meta-analysis of the pooled data revealed that the obliteration rate was significantly lower in the E+SRS group (OR 0.51, 95% CI 0.41–0.64, p < 0.00001). Symptomatic adverse radiation effects were observed in 6.6% (27/412 patients) and 11.1% (48/433 patients) of the E+SRS and SRS groups, respectively. The annual post-SRS hemorrhage rate was 2.0%–6.5% and 0%–2.0% for the E+SRS and SRS groups, respectively. The rates of permanent morbidity were 0%–6.7% and 0%–13.5% for the E+SRS and SRS groups, respectively.

CONCLUSIONS Arteriovenous malformation treatment with combined embolization and SRS is associated with lower obliteration rates than those with SRS treatment alone. However, this comparison does not fully account for differences in the initial AVM characteristics in the E+SRS group as compared with those in the SRS group. Further studies are warranted to address these limitations.

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Brainstem arteriovenous malformations: lesion characteristics and treatment outcomes

J Neurosurg 128:126–136, 2018

Brainstem arteriovenous malformations (AVMs) are rare lesions that are difficult to diagnose and treat. They are often more aggressive in their behavior when compared with their supratentorial counterparts. The consequence of a brainstem hemorrhage is often devastating, and many patients are in poor neurological status at presentation. The authors examine the factors associated with angiographically confirmed cure and those affecting management outcomes for these complex lesions.

METHODS This was a retrospective analysis of data gathered from the prospectively maintained Stanford AVM database. Lesions were grouped based on their location in the brainstem (medulla, pons, or midbrain) and the quadrant they occupied. Angiographic cure was dichotomized as completely obliterated or not, and functional outcome was dichotomized as either independent or not independent at last follow-up.

RESULTS Over a 23-year period, 39 lesions were treated. Of these, 3 were located in the medulla, 14 in the pons, and 22 in the midbrain. At presentation, 92% of the patients had hemorrhage, and only 43.6% were functionally independent. Surgery resulted in the best radiographic cure rates, with a morbidity rate of 12.5%. In all, 53% of patients either improved or remained stable after surgery. Absence of residual nidus and female sex correlated with better outcomes.

CONCLUSIONS Brainstem AVMs usually present with hemorrhage. Surgery offers the best chance of cure, either in isolation or in combination with other modalities as appropriate.

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Stereotactic Radiosurgery for Brainstem Arteriovenous Malformations

Neurosurgery 81:910–920, 2017

The management of brainstem arteriovenous malformations (bAVMs) is a formidable challenge. bAVMs harbor higher morbidity and mortality compared to other locations.

OBJECTIVE: To review the outcomes following stereotactic radiosurgery (SRS) of bAVMs in a multicenter study.

METHODS: Six medical centers contributed data from 205 patients through the International Gamma Knife Research Foundation. Median age was 32 yr (6-81). Median nidus volume was 1.4 mL (0.1-69 mL). Favorable outcome (FO) was defined as AVM obliteration and no post-treatment hemorrhage or permanent symptomatic radiation-induced complications.

RESULTS: Overall obliteration was reported in 65.4% (n = 134) at a mean follow-up of 69 mo. Obliteration was angiographically proven in 53.2% (n = 109) and on MRA in 12.2% (n=25). Actuarial rate of obliteration at 2, 3, 5, 7, and 10 yr after SRS was 24.5%, 43.3%, 62.3%, 73%, and 81.8% respectively. Patients treated with a margin dose >20 Gy were more likely to achieve obliteration (P = .001). Obliteration occurred earlier in patients who received a higher prescribed margin dose (P = .05) and maximum dose (P = .041). Post-SRS hemorrhage occurred in 8.8% (n = 18). Annual post gamma knife latency period hemorrhage was 1.5%. Radiation-induced complications were radiologically evident in 35.6% (n = 73), symptomatic in 14.6% (n=30), and permanent in 14.6% (n=30, which included long-tract signs and new cranial nerve deficits). FO was achieved in 64.4% (n = 132). Predictors of an FO were a higher Virginia radiosurgery AVM scale score (P = .003), prior hemorrhage (P = .045), and a lower prescribed maximum dose (P = .006).

CONCLUSION: SRS for bAVMs results in obliteration and avoids permanent complications in the majority of patients.

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Hemorrhage from cerebral cavernous malformations

J Neurosurg 126:1079–1087, 2017

The aim of this paper is to define an overall cavernous malformation (CM) hemorrhage rate and risk factors for hemorrhage.

METHODS The authors performed a systematic, pooled analysis via the PubMed database through October 2015 using the terms “cavernoma,” “cavernous malformation,” “natural history,” “bleeding,” and “hemorrhage.” English-language studies providing annual rates and/or risk factors for CM hemorrhage were included. Data extraction, performed independently by the authors, included demographic data, hemorrhage rates, and hemorrhage risk factors.

RESULTS Across 12 natural history studies with 1610 patients, the mean age at presentation was 42.7 years old and 52% of patients (95% CI 49%–55%) were female. Presentation modality was seizure in 30% (95% CI 25%–35%), hemorrhage in 26% (95% CI 17%–37%), incidental in 17% (95% CI 9%–31%), and focal deficits only in 16% of cases (95% CI 11%–23%). CM location was lobar in 66% (95% CI 61%–70%), brainstem in 18% (95% CI 13%–24%), deep supratentorial in 8% (95% CI 6%–10%), and cerebellar in 8% (95% CI 5%–11%). Pooling 7 studies that did not assume CM presence since birth, the annual hemorrhage rate was 2.5% per patient-year over 5081.2 patient-years of follow-up (95% CI 1.3%–5.1%). Pooling hazard ratios across 5 studies that evaluated hemorrhage risk factors, prior CM hemorrhage was a significant risk factor for hemorrhage (HR 3.73, 95% CI 1.26–11.1; p = 0.02) while younger age, female sex, deep location, size, multiplicity, and associated developmental venous anomalies (DVAs) were not.

CONCLUSIONS Although limited by the heterogeneity of incorporated reports and selection bias, this study found prior hemorrhage to be a significant risk factor for CM bleeding, while age, sex, CM location, size, multiplicity, and associated DVAs were not. Future natural history studies should compound annual hemorrhage rate with prospective seizure and nonhemorrhagic neurological deficit rates.

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Staged-Volume Radiosurgery of Large Arteriovenous Malformations Improves Outcome by Reducing the Rate of Adverse Radiation Effects

Neurosurgery 80:180–192, 2017

The treatment of large arteriovenous malformations (AVMs) remains challenging. Recently, staged-volume radiosurgery (SVRS) has become an option.

OBJECTIVE: To compare the outcome of SVRS on large AVMs with our historical, single- stage radiosurgery (SSRS) series.

METHODS: We have been prospectively collecting data of patients treated by SVRS since 2007. There were 84 patients who had a median age of 37 years (range, 9-62 years) who were treated until July 2013. The outcomes of 76 of those who had follow-ups available were analyzed and compared with the outcomes of 122 patients treated with the best SSRS technique.

RESULTS: There were 21.5% of AVMs that were deep seated, and 44% presented with hemorrhage resulting in 45% fixed neurological deficit. There were 14% of patients who had undergone embolization before radiosurgery. The median nidus treatment volume was 19.7 cm 3 (6.65-68.7) and 17.5 Gy (13-22.5) prescription isodose was given. Of the 44 lesions having radiological follow-up at 4 years, 61.4% were completely obliterated. Previous embolization (50% with and 63% without) and higher Spetzler-Martin grades appeared to be the negative factors in successful obliteration, but treatment volume was not. Within 3 years after radiosurgery, the annual bleed rates of unruptured and previously ruptured AVMs were 3.2% and 5.6%, respectively. Three bleeds were fatal and 2 resulted in significant modified Rankin scale 3 morbidity. These rates differ little from SSRS. Temporary adverse radiation effects (AREs) did not change significantly, but permanent AREs dropped from 15% to 6.5% (P = .03) compared with SSRS.

CONCLUSION: Obliteration and hemorrhage rates of large AVMs treated by SVRS are similar to historical SSRS. However, SVRS offers a lower rate of AREs.

 

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Stereotactic Radiosurgery for Arteriovenous Malformations: The Effect of Treatment Period on Patient Outcomes

AVM

Neurosurgery 78:499–509, 2016

Stereotactic radiosurgery (SRS) has been performed on patients with cerebral arteriovenous malformations (AVMs) for over 40 years.

OBJECTIVE: To evaluate the impact of treatment period on obliteration, intracranial hemorrhage (ICH), and radiation-induced complications (RICs).

METHODS: Retrospective comparison of 381 AVM patients having SRS during a 20-year period (group 1, January 1990 through March 1997, n = 160; group 2, April 1997 through December 2009, n = 221). The median radiological and clinical follow-up after initial SRS was 77 months and 93 months, respectively.

RESULTS: Obliteration was 59.1% at 4 years and 85.1% at 8 years. Obliteration was more common in patients with hemispheric or cerebellar AVMs (P = .001), smaller prescription isodose volume (PIV) (P < .001), and group 1 patients (P < .001). The ICH rate was 7.7% at 4 years and 10.6% at 8 years. ICH was more common in older patients (P = .02), patients with deep AVM (P = .01), and larger PIV (P < .001). There was no difference in the ICH rate between the treatment groups (P = .18). The rate of permanent RICs was 4.4% at 4 years and 8.6% at 8 years. RICs were more common with larger PIVs (P < .001) and group 1 patients (P = .02). There was no difference in the number of patients having obliteration without new deficits between the 2 treatment periods (68.8% vs 73.3%, P = .33).

CONCLUSION: Advances in SRS procedures over the past 20 years have resulted in a lower risk of RIC, but fewer patients had AVM obliteration. Increasing the prescription dose for patients with medium- and large-volume AVMs by using current conformal dose-planning techniques may improve the obliteration rate while maintaining a low risk of RICs.

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Silent Arteriovenous Malformation Hemorrhage and the Recognition of “Unruptured” Arteriovenous Malformation Patients Who Benefit From Surgical Intervention

Silent Arteriovenous Malformation Hemorrhage and the Recognition of “Unruptured” Arteriovenous Malformation Patients Who Benefit From Surgical Intervention

Neurosurgery 76:592–600, 201

Arteriovenous malformation (AVM) patients present in 4 ways relative to hemorrhage: (1) unruptured, without a history or radiographic evidence of old hemorrhage (EOOH); (2) silent hemorrhage, without a bleeding history but with EOOH; (3) ruptured, with acute bleeding but without EOOH; and (4) reruptured, with acute bleeding and EOOH. OBJECTIVE: We hypothesized that characteristics and outcomes in the unrecognized group of silent hemorrhage patients may differ from those of unruptured patients.

METHODS: Two hundred forty-two patients operated-on since 1997 were categorized by hemorrhage status and hemosiderin positivity in this cohort study: unruptured (group 1), silent hemorrhage (group 2), and ruptured/reruptured (group 3/4). Group 3/4 was combined because hemosiderin cannot distinguish acute hemorrhage from older silent hemorrhage.

RESULTS: Hemosiderin was found in 45% of specimens. Seventy-five patients (31.0%) had unruptured AVMs, 30 (12.4%) had silent hemorrhage, and 137 (56.6%) had ruptured/ reruptured AVMs. Deep drainage, posterior fossa location, preoperative modified Rankin Scale (mRS) score, outcome, and macrophage score were different across groups. Only the macrophage score was different between the groups without clinical hemorrhage. Outcomes were better in silent hemorrhage patients than in those with frank rupture (mean mRS scores of 1.2 and 1.7, respectively).

CONCLUSION: One-third of patients present with silent AVM hemorrhage. No clinical or anatomic features differentiate these patients from unruptured patients, except the presence of hemosiderin and macrophages. Silent hemorrhage can be diagnosed using magnetic resonance imaging with iron-sensitive imaging. Silent hemorrhage portends an aggressive natural history, and surgery halts progression to rerupture. Good final mRS outcomes and better outcomes than in those with frank rupture support surgery for silent hemorrhage patients, despite the findings of ARUBA.

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Age-related differences in unruptured intracranial aneurysms: 1-year outcomes

Aneurysm surgery

J Neurosurg 121:1024–1038, 2014

The aim of this study was to determine age-related differences in short-term (1-year) outcomes in patients with unruptured intracranial aneurysms (UIAs).

Methods. Four thousand fifty-nine patients prospectively enrolled in the International Study of Unruptured Intracranial Aneurysms were categorized into 3 groups by age at enrollment: < 50, 50–65, and > 65 years old. Outcomes assessed at 1 year included aneurysm rupture rates, combined morbidity and mortality from aneurysm procedure or hemorrhage, and all-cause mortality. Periprocedural morbidity, in-hospital morbidity, and poor neurological outcome on discharge (Rankin scale score of 3 or greater) were assessed in surgically and endovascularly treated groups. Univariate and multivariate associations of each outcome with age were tested.

Results. The risk of aneurysmal hemorrhage did not increase significantly with age. Procedural and in-hospital morbidity and mortality increased with age in patients treated with surgery, but remained relatively constant with increasing age with endovascular treatment. Poor neurological outcome from aneurysm- or procedure-related morbidity and mortality did not differ between management groups for patients 65 years old and younger, but was significantly higher in the surgical group for patients older than 65 years: 19.0% (95% confidence interval [CI] 13.9%–24.4%), compared with 8.0% (95% CI 2.3%–13.6%) in the endovascular group and 4.2% (95% CI 2.3%–6.2%) in the observation group. All-cause mortality increased steadily with increasing age, but differed between treatment groups only in patients < 50 years of age, with the surgical group showing a survival advantage at 1 year.

Conclusions. Surgical treatment of UIAs appears to be safe, prevents 1-year hemorrhage, and may confer a survival benefit in patients < 50 years of age. However, surgery poses a significant risk of morbidity and death in patients > 65 years of age. Risk of endovascular treatment does not appear to increase with age. Risks and benefits of treatment in older patients should be carefully considered, and if treatment is deemed necessary for patients older than 65 years, endovascular treatment may be the best option.

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Stereotactic radiosurgery for Spetzler-Martin Grade III arteriovenous malformations

Spetzler-Martin grade III AVMs

J Neurosurg 120:973–981, 2014

The purpose of this study was to define the outcomes and risks of stereotactic radiosurgery (SRS) for Spetzler-Martin (SM) Grade III arteriovenous malformations (AVMs).

Methods. Between 1987 and 2009, SRS was performed in 474 patients with SM Grade III AVMs. The AVMs were categorized by scoring the size (S), drainage (D), and location (L): IIIa was a small AVM (S1D1L1, N = 282); IIIb was a medium/deep AVM (S2D1L0, N = 44); and IIIc was a medium/eloquent AVM (S2D0L1, N = 148). The median target volume was 3.8 ml (range 0.1–26.3 ml) and the margin dose was 20 Gy (range 13–25 Gy). Eighty-one patients (17%) underwent prior embolization, and 58 (12%) underwent prior resection.

Results. At a mean follow-up of 89 months, the total obliteration rates documented by angiography or MRI for all SM Grade III AVMs increased from 48% at 3 years to 69% at 4 years, 72% at 5 years, and 77% at 10 years. The SM Grade IIIa AVMs were more likely to obliterate than other subgroups. The cumulative rate of hemorrhage was 2.3% at 1 year, 4.4% at 2 years, 5.5% at 3 years, 6.4% at 5 years, and 9% at 10 years. The SM Grade IIIb AVMs had a significantly higher cumulative rate of hemorrhage. Symptomatic adverse radiation effects were detected in 6%.

Conclusions. Treatment with SRS was an effective and relatively safe management option for SM Grade III AVMs. Although patients with residual AVMs remained at risk for hemorrhage during the latency interval, the cumulative 10-year 9% hemorrhage risk in this series may represent a significant reduction compared with the expected natural history.

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Spinal extradural arteriovenous fistulas

Spinal extradural arteriovenous fistulas

J Neurosurg Spine 19:582–590, 2013

Our understanding of spinal extradural arteriovenous fistulas (eAVFs) is relatively limited. In this study the authors aimed to provide the demographics, natural history, and treatment results of these rare lesions.

Methods. The authors performed a pooled analysis of data in the PubMed database through December 2012. Individualized patient data were extracted to elucidate demographic, clinical, and angioarchitectural features of spinal eAVFs as well as outcomes following different treatment strategies.

Results. Information on 101 patients was extracted from 63 eligible studies. The mean patient age was 45.9 years, and there was no significant overall sex predilection. Only 3% of the lesions were incidental, whereas 10% occurred in patients who had presented with hemorrhage. None of the 64 patients with at least 1 month of untreated follow-up sustained a hemorrhage over a total of 83.8 patient-years. Patients with lumbosacral eAVFs were significantly older (mean age 58.7 years, p < 0.0001), were significantly more often male (70% male, p = 0.02), had significantly worse presenting Aminoff-Logue motor and bladder scores (p = 0.0008 and < 0.0001, respectively), and had the greatest prevalence of lesions with intradural venous drainage (62% of cases, p < 0.0001). Neurofibromatosis Type 1 (30% of cases, p < 0.0001) and subarachnoid hemorrhage (9% of cases, p = 0.06) were associated with and exclusively found in patients with cervical eAVFs. The overall complete obliteration rate was 91%. After a mean follow-up of 1.7 years, the clinical condition was improved in 89% of patients, the same in 9%, and worse in 2%. Obliteration rates and outcome at follow-up did not significantly differ between surgical and endovascular treatment modalities.

Conclusions. Spinal eAVFs are rare lesions with a low risk of hemorrhage; they cause neurological morbidity as a result of mass effect and/or venous hypertension. Their treatment is associated with a high rate of complete obliteration and improvement in preoperative symptoms.

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Biopsy of the Superficial Cortex: Predictors of Effectiveness and Outcomes

Biopsy of the Superficial Cortex

Neurosurgery 73:224–232, 2013 

Brain biopsies of superficial cortex are performed for diagnosis of neurological diseases, but preoperative predictors of successful diagnosis and risks are lacking.

OBJECTIVE: We evaluated effectiveness and outcomes of superficial cortical biopsies and determined preoperative predictors of diagnosis, outcomes, morbidities, and mortality.

METHODS: A single-institution retrospective analysis of 170 patients who underwent open brain biopsies of superficial cortex was performed. Clinical predictors of effectiveness and outcomes were determined using univariate/multivariate analyses and a system for risk-benefit stratification was created and tested.

RESULTS: Brain biopsies led to successful diagnosis in 122 of 170 (71.8%) and affected management in 97 of 170 (57.1%) cases. Factors increasing the odds of diagnostic pathology included age older than 45 years (odds ratio [OR]: 2.67, 95% confidence interval [CI]: 1.34-5.27, P < .01), previous cancer diagnosis (OR: 3.64, 95% CI: 1.69-7.85, P < .001), focal (OR: 3.90, 95% CI: 1.91-8.00, P< .001) and enhancing (OR: 5.03, 95% CI: 2.41-10.52, P< .001) lesions on magnetic resonance imaging, biopsy of specific lesions on magnetic resonance imaging (OR: 9.34, 95% CI: 4.29-20.33, P < .001), and use of intraoperative navigation (OR: 6.59, 95% CI: 3.04-14.28, P < .001). Brain biopsies led to symptomatic intracranial hemorrhage, seizures, other significant morbidities, and perioperative mortality in 12.4%, 16.2%, 37.1%, and 8% of cases, respectively. Risk of postoperative intracranial hemorrhage was increased by a history of aspirin use (OR: 2.51, 95% CI: 1.23-5.28, P < .05) and age older than 60 years (OR: 2.66, 95% CI: 1.36-5.18, P < .01).

CONCLUSION: Effectiveness and risk of morbidity/mortality can be estimated preoperatively for patients undergoing open brain biopsies of the superficial cortex. Older age and specific imaging characteristics increase the odds of diagnostic biopsy. Conversely, older age and aspirin use increases the risk of postoperative complications.

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