Risk factors for worsened muscle strength after the surgical treatment of arteriovenous malformations of the eloquent motor area

Application of diffusion tensor-based tractography in treatment of brain arteriovenous malformations: a systematic review

There is no systematic review investigating the utility of Diffusion tensor-based tractography findings for treating brain arteriovenous malformations (bAVMs). This systematic review aims to investigate the outcomes following bAVM treatment when tractography data is incorporated into treatment planning. PubMed/MEDLINE, Scopus, and Cochrane Library, were searched for published studies. Prospective or retrospective studies involving at least one patient with confirmed bAVM and available data on tractography and clinical outcomes were included. A total of 16 studies were eligible for this review, consisting of 298 patients. 48.2% of patients were female. The mean age of the patients was 27.5 years (range: 5-77). Stereotactic radiosurgery (SRS) and microsurgical resection each were the treatment of choice in eight studies, respectively. Two-hundred forty-eight patients underwent SRS as the primary treatment, while microsurgery was used to resect the bAVMs in 50 patients. The corticospinal tract, optic pathway, and arcuate fasciculus were the most widely investigated white matter tracts. Tractography disruption and failure frequencies were 19.1% and 1.8%, respectively. The pooled proportions (95% CI) of obliteration rates were 88.78% (73.51-95.76) for microsurgery and 51.45% (13-17-88.10) following SRS. Treatment-related non-hemorrhagic complications rates occurred in 24.2% and 9.9% of patients who underwent microsurgical resection and SRS, respectively. Tractography findings can contribute to providing a more accurate dosimetry analysis of functional white matter tracts at risk prior to SRS and minimizing the surgical morbidity following microsurgical resection.

Artificial Intelligence-Assisted Evaluation of the Spatial Relationship between Brain Arteriovenous Malformations and the Corticospinal Tract to Predict Postsurgical Motor Defects

BACKGROUND AND PURPOSE

Preoperative evaluation of brain AVMs is crucial for the selection of surgical candidates. Our goal was to use artificial intelligence to predict postsurgical motor defects in patients with brain AVMs involving motor-related areas.

MATERIALS AND METHODS

Eighty-three patients who underwent microsurgical resection of brain AVMs involving motor-related areas were retrospectively reviewed. Four artificial intelligence-based indicators were calculated with artificial intelligence on TOF-MRA and DTI, including FN5mm/50mm (the proportion of fiber numbers within 5-50mm from the lesion border), FN10mm/50mm (the same but within 10-50mm), FP5mm/50mm (the proportion of fiber voxel points within 5-50mm from the lesion border), and FP10mm/50mm (the same but within 10-50mm). The association between the variables and long-term postsurgical motor defects was analyzed using univariate and multivariate analyses. Least absolute shrinkage and selection operator regression with the Pearson correlation coefficient was used to select the optimal features to develop the machine learning model to predict postsurgical motor defects. The area under the curve was calculated to evaluate the predictive performance.

RESULTS

In patients with and without postsurgical motor defects, the mean FN5mm/50mm, FN10mm/50mm, FP5mm/50mm, and FP10mm/50mm were 0.24 (SD, 0.24) and 0.03 (SD, 0.06), 0.37 (SD, 0.27) and 0.06 (SD, 0.08), 0.06 (SD, 0.10) and 0.01 (SD, 0.02), and 0.10 (SD, 0.12) and 0.02 (SD, 0.05), respectively. Univariate and multivariate logistic analyses identified FN10mm/50mm as an independent risk factor for long-term postsurgical motor defects (P = .002). FN10mm/50mm achieved a mean area under the curve of 0.86 (SD, 0.08). The mean area under the curve of the machine learning model consisting of FN10mm/50mm, diffuseness, and the Spetzler-Martin score was 0.88 (SD, 0.07).

CONCLUSIONS

The artificial intelligence-based indicator, FN10mm/50mm, can reflect the lesion-fiber spatial relationship and act as a dominant predictor for postsurgical motor defects in patients with brain AVMs involving motor-related areas.

Chinese Cerebrovascular Neurosurgery Society and Chinese Interventional & Hybrid Operation Society, of Chinese Stroke Association Clinical Practice Guidelines for Management of Brain Arteriovenous Malformations in Eloquent Areas

Aim: The aim of this guideline is to present current and comprehensive recommendations for the management of brain arteriovenous malformations (bAVMs) located in eloquent areas. Methods: An extended literature search on MEDLINE was performed between Jan 1970 and May 2020. Eloquence-related literature was further screened and interpreted in different subcategories of this guideline. The writing group discussed narrative text and recommendations through group meetings and online video conferences. Recommendations followed the Applying Classification of Recommendations and Level of Evidence proposed by the American Heart Association/American Stroke Association. Prerelease review of the draft guideline was performed by four expert peer reviewers and by the members of Chinese Stroke Association. Results: In total, 809 out of 2,493 publications were identified to be related to eloquent structure or neurological functions of bAVMs. Three-hundred and forty-one publications were comprehensively interpreted and cited by this guideline. Evidence-based guidelines were presented for the clinical evaluation and treatment of bAVMs with eloquence involved. Topics focused on neuroanatomy of activated eloquent structure, functional neuroimaging, neurological assessment, indication, and recommendations of different therapeutic managements. Fifty-nine recommendations were summarized, including 20 in Class I, 30 in Class IIa, 9 in Class IIb, and 2 in Class III. Conclusions: The management of eloquent bAVMs remains challenging. With the evolutionary understanding of eloquent areas, the guideline highlights the assessment of eloquent bAVMs, and a strategy for decision-making in the management of eloquent bAVMs.

Systematic Review of Functional Mapping and Cortical Reorganization in the Setting of Arteriovenous Malformations, Redefining Anatomical Eloquence

Objective: The goal of this study was to systematically review functional mapping and reorganization that takes place in the setting of arteriovenous malformations (AVMs) and its potential impact on grading and surgical decision making.

Methods: A systematic literature review was performed using the PubMed database for studies published between 1986 and 2019. Studies assessing brain mapping and functional reorganization in AVMs were included.

Results: Of the total 84 articles identified in the original literature search, 12 studies were ultimately selected. This includes studies evaluating the impact of cortical reorganization on patient outcomes and factors impacting and triggering cortical reorganization in AVM.

Conclusion: These studies demonstrate the utility of preoperative brain mapping and acknowledgment of functional reorganization in the setting of AVMs. While these findings led to alterations in Spetzler–Martin grading and subsequent surgical decision making, it remains unclear the clinical utility of this information when assessing patient outcomes. While promising, more research is required before recommendations can be made regarding functional brain mapping and cortical reorganization with respect to AVM surgery involving eloquent brain tissue.

Plasticity in language cortex and white matter tracts after resection of dominant inferior parietal lobule arteriovenous malformations: a combined fMRI and DTI study

OBJECTIVE

The dominant inferior parietal lobe (IPL) contains cortical and subcortical structures that serve language processing. A high incidence of postoperative short-term aphasia and good potential for language reorganization have been observed. The authors' goal was to study the plasticity of the language cortex and language-related fibers in patients with brain arteriovenous malformations (BAVMs) located in the IPL.

METHODS

A total of 6 patients who underwent microsurgical treatment of an IPL BAVM were prospectively recruited between September 2016 and May 2018. Blood oxygen level-dependent functional MRI (BOLD-fMRI) and diffusion tensor imaging (DTI) were performed within 1 week before and 6 months after microsurgery. Language-related white matter (WM) eloquent fiber tracts and their contralateral homologous fiber tracts were tracked. The Western Aphasia Battery was administered to assess language function. The authors determined the total number of fibers and mean fractional anisotropy (FA) indices for each individual tract. In addition, they calculated the laterality index (LI) between the activated language cortex voxels in the lesional and contralesional hemispheres and compared these indices between the preoperative and postoperative fMR and DT images.

RESULTS

Of the 6 patients with IPL BAVMs, all experienced postoperative short-term language deficits, and 5 (83.3%) recovered completely at 6 months after surgery. Five patients (83.3%) had right homologous reorganization of BOLD signal activations in both Broca's and Wernicke's areas. More fibers were observed in the arcuate fasciculus (AF) in the lesional hemisphere than in the contralesional hemisphere (1905 vs 254 fibers, p = 0.035). Six months after surgery, a significantly increased number of fibers was seen in the right hemispheric AF (249 fibers preoperatively vs 485 postoperatively, p = 0.026). There were significantly more nerve fibers in the postoperative left inferior frontooccipital fasciculus (IFOF) (874 fibers preoperatively vs 1186 postoperatively, p = 0.010). A statistically significant increase in right hemispheric dominance of Wernicke's area was observed. The overall functional LI showed functional lateralization of Wernicke's area in the right hemisphere (LI ≤ -0.20) in all patients.

CONCLUSIONS

The authors' findings provide evidence for the functional reorganization by recruiting the right hemispheric homologous region of Broca's and Wernicke's areas, right hemispheric AFs, and left hemispheric IFOFs following resection of IPL BAVMs.Clinical trial registration no.: NCT02868008 (clinicaltrials.gov).

Does eloquence subtype influence outcome following arteriovenous malformation surgery?

OBJECTIVE

Although numerous arteriovenous malformation (AVM) grading scales consider eloquence in risk assessment, none differentiate the types of eloquence. The purpose of this study was to determine if eloquence subtype affects clinical outcome.

METHODS

This is a retrospective review of a prospectively collected clinical database of brain AVMs treated with microsurgery in the period from 1997 to 2017. The only inclusion criterion for this study was the presence of eloquence as defined by the Spetzler-Martin grading scale. Eloquence was preoperatively categorized by radiologists. Poor outcome was defined as a modified Rankin Scale (mRS) score 3-6, and worsening clinical status was defined as an increase in the mRS score at follow-up. Logistic regression analyses were performed.

RESULTS

Two hundred forty-one patients (49.4% female; average age 33.9 years) with eloquent brain AVMs were included in this review. Of the AVMs (average size 2.7 cm), 54.4% presented with hemorrhage, 46.2% had deep venous drainage, and 17.0% were diffuse. The most common eloquence type was sensorimotor (46.1%), followed by visual (27.0%) and language (22.0%). Treatments included microsurgery alone (32.8%), microsurgery plus embolization (51.9%), microsurgery plus radiosurgery (7.9%), and all three modalities (7.5%). Motor mapping was used in 9% of sensorimotor AVM cases, and awake speech mapping was used in 13.2% of AVMs with language eloquence. Complications occurred in 24 patients (10%). At the last follow-up (average 24 months), 71.4% of the patients were unchanged or improved and 16.6% had a poor outcome. There was no statistically significant difference in the baseline patient and AVM characteristics among the different subtypes of eloquence. In a multivariate analysis, in comparison to visual eloquence, both sensorimotor (OR 7.4, p = 0.004) and language (OR 6.5, p = 0.015) eloquence were associated with poor outcomes. Additionally, older age (OR 1.31, p = 0.016) and larger AVM size (OR 1.37, p = 0.034) were associated with poor outcomes.

CONCLUSIONS

Unlike visual eloquence, sensorimotor and language eloquence were associated with worse clinical outcomes after the resection of eloquent AVMs. This nuance in AVM eloquence demands consideration before deciding on microsurgical intervention, especially when numerical grading systems produce a score near the borderline between operative and nonoperative management.

Surgical outcome of motor deficits and neurological status in brainstem cavernous malformations based on preoperative diffusion tensor imaging: a prospective randomized clinical trial

OBJECTIVE: Surgical management of brainstem lesions is challenging due to the highly compact, eloquent anatomy of the brainstem. This study aimed to evaluate the safety and efficacy of preoperative diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) in brainstem cavernous malformations (CMs). METHODS: A prospective randomized controlled clinical trial was performed by using stratified blocked randomization. The primary eligibility criterion of the study was being a surgical candidate for brainstem CMs (with informed consent). The study enrolled 23 patients who underwent preoperative DTI/DTT and 24 patients who did not (the control group). The pre- and postoperative muscle strength of both limbs and modified Rankin Scale (mRS) scores were evaluated. Muscle strength of any limb at 12 months after surgery at the clinic visit was the primary outcome; worsened muscle strength was considered to be a poor outcome. Outcome assessors were blinded to patient management. This study reports the preliminary results of the interim analysis. RESULTS: The cohort included 47 patients (22 women) with a mean age of 35.7 years. The clinical baselines between these 2 groups were not significantly different. In the DTI/DTT group, the corticospinal tract was affected in 17 patients (73.9%): it was displaced, deformed/partially interrupted, or completely interrupted in 6, 7, and 4 patients, respectively. The surgical approach and brainstem entry point were adjusted in 3 patients (13.0%) based on DTI/DTT data. The surgical morbidity of the DTI/DTT group (7/23, 30.4%) was significantly lower than that of the control group (19/24, 79.2%, p = 0.001). At 12 months, the mean mRS score (1.1, p = 0.034) and percentage of patients with worsened motor deficits (4.3%, p = 0.006) were significantly lower in the DTI/DTT group than in the control group (1.7% and 37.5%). Multivariate logistic regression identified the absence of preoperative DTI/DTT (OR 0.06, 95% CI 0.01-0.73, p = 0.028) and use of the 2-point method (OR 4.15, 95% CI 1.38-12.49, p = 0.011) as independent adverse factors for a worsened motor deficit. The multivariate model found a significant correlation between poor mRS score and both an increased preoperative mRS score (t = 3.559, p = 0.001) and absence of preoperative DTI/DTT (t = -2.747, p = 0.009). CONCLUSIONS: DTI/DTT noninvasively allowed for visualization of the anatomical relationship between vital tracts and pathologies as well as facilitated the brainstem surgical approach and entry-point decision making. The technique was valuable for complex neurosurgical planning to reduce morbidity. Nonetheless, DTI/DTT data should be interpreted cautiously.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: randomized controlled trial; evidence: class I. Clinical trial registration no.: NCT01758211 (ClinicalTrials.gov).

Technique of Fractionated Transcatheter Arterial Embolization for Treating Large Arteriovenous Malformation in Brain Functional Area

OBJECTIVE

At present, large cranial function area arteriovenous malformation (fAVM) is mainly treated by craniotomy with a high risk of operation and high disability. In recent years, with the continuous improvement of the neural intervention technology, fractionated transcatheter arterial embolization (fTAE) may be used to treat the fAVM instead of surgical treatment. However, its effectiveness for treating fAVM has never been explored. The authors hypothesized that fTAE can be effective in the treatment of fTAE.

METHODS

A retrospective study was conducted in 229 cases of large fAVM in multicenter hospitals. Among them, 103 cases were performed fTAE and the other 126 cases were carried on minimally invasive craniotomy (MIC). Clinically relevant symptomatic improvement and complications were compared between 2 groups.

RESULTS

Complete resection rate of arteriovenous malformation in MIC group (100%) was significantly higher than that of complete embolization rate in fTAE group (77.7%) (P = 0.000). However, the incidence of postoperative complications includes decreased limb muscle strength (P = 0.001), sensory loss of extremities (P = 0.003), visual field defect (P = 0.025) that were lower in fTAE group and remission rate of headache (P = 0.012) but not epilepsy (P = 0.952) was higher in fTAE group compared with that in MIC group. After 1 year follow-up, the rebleeding rate in the fTAE treatment group was 4.85%, higher than that in MIC group (0%) (P = 0.000).

CONCLUSIONS

Fractionated transcatheter arterial embolization therapy is beneficial for reducing the postoperative complications and preoperative symptoms of fAVM, but not for recurrence rate.

A Tractography-Based Grading Scale of Brain Arteriovenous Malformations Close to the Corticospinal Tract to Predict Motor Outcome After Surgery

Background: Surgical decision-making for brain arteriovenous malformations (AVMs) close to the corticospinal tract (CST) is always challenging. The purpose of this study was to develop a tractography-based grading scale to improve preoperative risk prediction and patient selection.

Methods: We analyzed a consecutive, surgically treated series of 90 patients with AVMs within a 10-mm range from the CST demonstrated by preoperative diffusion tensor tractography. Poor motor outcome was defined as persistent postoperative limb weakness. We examined the predictive ability of nidus-to-CST distance (NCD), the closest CST level (CCL), deep perforating artery supply, as well as variables of the supplemented Spetzler-Martin grading system. Three logistic models were derived from different multivariable logistic regression analyses, of which the most predictive model was selected to construct a prediction grading scale. Receiver operating characteristic analysis was conducted to test the predictive accuracy of the grading scale.

Results: Twenty-one (23.3%) patients experienced persistent postoperative limb weakness after a mean 2.7-year follow-up. The most predictive logistic model showed NCD (P = 0.001), CCL (P = 0.017), patient age (P = 0.004), and AVM diffuseness (P = 0.021) were independent predictors for poor motor outcome. We constructed the CLAD grading scale incorporating these predictors. The predictive accuracy of the CLAD grade was better compared with the supplemented Spetzler-Martin grade (area under curve = 0.84 vs. 0.68, P = 0.023).

Conclusions: Both NCD and CCL predict motor outcome after resection of AVMs close to the CST. We propose the CLAD grading scale as an effective risk-prediction tool in surgical decision-making.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT01758211 and NCT02868008

One-staged in situ embolization combined with surgical resection for eloquence protection of AVM: technical note

Brain arteriovenous malformations (AVMs) near/within eloquent areas are challenging to treat surgically. The insufficient lesion-to-eloquence distance (LED) is related to poor neurological outcomes. This paper reports the use of in situ embolization combined with surgical resection in a one-staged hybrid operation for eloquent area protection. Nine patients who underwent one-staged in situ embolization combined with surgical resection were selected from the database of a prospective clinical trial (NCT03774017). Nidus got partial in situ embolization in the parts located near/within the eloquence. The rest of nidus was removed via a microsurgical procedure in the same operation. The in situ embolization ensured a sufficient LED to prevent eloquent areas and tracts from being damaged in the subsequent resection. All of the patients achieved complete obliteration with no neurological deficits or complications. One-staged hybrid operation initiates closer cooperation between surgical and endovascular treatments and proposes an integrative therapeutic mode for AVMs. The in situ embolization combined with surgical resection is safe and effective for improving the functional outcome of AVMs with eloquence and tracts involved. The clinical trial is registered at ClinicalTrials.gov (NCT03774017, https://clinicaltrials.gov/ct2/show/NCT03774017 ).

Supratentorial cavernous malformations adjacent to the corticospinal tract: surgical outcomes and predictive value of diffusion tensor imaging findings

OBJECTIVE

Diffusion tensor imaging (DTI) findings may facilitate clinical decision making in patients with supratentorial cavernous malformations adjacent to the corticospinal tract (CST-CMs). The objective of this study was to determine the predictive value of preoperative DTI findings for surgical outcomes in patients with CST-CMs.

METHODS

A prospectively maintained database of patients with CM referred to the authors' hospital between September 2012 and October 2015 was reviewed to identify all consecutive surgically treated patients with CST-CM. All patients had undergone sagittal T1-weighted anatomical imaging and DTI before surgery. Both DTI findings and clinical characteristics of the patients and lesions were analyzed with respect to surgery-related motor deficits. DTI findings included lesion-to-CST distance (LCD) and the alteration (i.e., deviation, interruption, or degeneration due to the CM) of CST on preoperative DTI images. Surgery-related motor deficits at 1 week and the last clinic visit (≥ 3 months) after surgery were defined as short-term and long-term deficits, respectively. Preoperative and final modified Rankin Scale scores were also analyzed to identify the surgical outcomes in these patients.

RESULTS

A total of 56 patients with 56 CST-CMs were included in this study. The mean LCD was 3.9 ± 3.2 mm, and alterations of the CST were detected in 20 (36.7%) patients. One week after surgery, 21 (37.5%) patients had short-term surgery-related motor deficits, but only 14 (25.0%) patients had long term deficits at the last clinical visit. The mean patient follow-up was 14.7 ± 10.1 months. The difference between preoperative and final modified Rankin Scale scores was not statistically significant (p = 0.490). Multivariate analysis showed that both short-term (p < 0.001) and long-term (p = 0.002) surgery-related motor deficits were significantly associated with LCD. Receiver operating characteristic (ROC) curve results were as follows: for short-term surgery-related motor deficits, the area under the ROC curve (AUC) was 0.860, and the cutoff point was LCD = 2.55 mm; for long-term deficits, the AUC was 0.894, and the cutoff point was LCD = 2.30 mm. Both univariate (p = 0.012) and multivariate (p = 0.049) analyses revealed that CST alteration on preoperative DTI was significantly correlated with short-term surgery-related motor deficits. On univariate analysis, deep location of the CST-CMs was significantly correlated with long-term motor deficits (p = 0.016). Deep location of the CST-CMs had a trend toward significance with long-term motor deficits on the multivariate analysis (p = 0.060).

CONCLUSIONS

To facilitate clinical practice, the authors propose that 3.00 mm (2.55 to ∼3.00 mm) may be the safe LCD for surgery in patients with CST-CMs. A CST alteration on preoperative DTI and a deep location of the CST-CM may be risk factors for short- and long-term surgery-related motor deficits, respectively. A randomized controlled trial is needed to demonstrate the predictive value of preoperative DTI findings on surgical outcomes in patients with CST-CMs in future studies.

Risk factors for neurological deficits after surgical treatment of brain arteriovenous malformations supplied by deep perforating arteries

The treatment of brain arteriovenous malformations supplied by deep perforating arteries (PA) (P-BAVM) remains challenging. The aims of this study were to determine the outcomes after surgical treatment in patients with P-BAVMs and to identify the risk factors associated with postoperative neurological deficits. We retrospectively reviewed the medical charts and imaging records of 228 consecutive patients with BAVMs who underwent microsurgical resection of their BAVMs at Beijing Tiantan Hospital between September 2012 and March 2016. Patients were included if the BAVMs were totally or partially supplied by PA. All patients had undergone preoperative diffusion tensor imaging (DTI), MRI, 3D time-of-flight MRA (3D TOF-MRA) and digital subtraction angiography (DSA) followed by resection. Both functional and angioarchitectural factors were analysed with respect to the postoperative neurological deficits, including motor deficits, visual field deficits and aphasia. Statistical analysis was performed using the statistical package SPSS (version 20.0.0, IBM Corp.). Fifty-nine patients with P-BAVMs were enrolled. Radical obliteration was achieved in all P-BAVMs according to postoperative DSA. Forty-five (76.3%) patients obtained neurological deficits 1 week after surgery. At a mean follow-up of 14.7 ± 9.4 (3-30) months after surgery, 34 patients (57.6%) had long-term neurological deficits. Multivariable logistic regression analyses showed that a shorter lesion-to-eloquent fibre tracts distance (LFD) was an independent risk factor for short- (P = 0.014) and long-term (P = 0.013) neurological deficits. The cut-off point of LFD for long-term neurological deficits was 5.20 mm. The predominant supply of the PA (P = 0.008) was an independent risk factor for long-term neurological deficits. This study identified a high risk of surgical morbidity for P-BAVMs. The predominant supply of the PA and a shorter LFD are crucial risk factors for postoperative neurological deficits in patients with P-BAVMs.

A supplementary grading scale combining lesion-to-eloquence distance for predicting surgical outcomes of patients with brain arteriovenous malformations

OBJECTIVE Case selection for the surgical treatment of brain arteriovenous malformations (BAVMs) remains challenging. This study aimed to construct a predictive grading system combining lesion-to-eloquence distance (LED) for selecting patients with BAVMs for surgery. METHODS Between September 2012 and September 2015, the authors retrospectively studied 201 consecutive patients with BAVMs. All patients had undergone preoperative functional MRI and diffusion tensor imaging (DTI), followed by resection. Both angioarchitectural factors and LED were analyzed with respect to the change between preoperative and final postoperative modified Rankin Scale (mRS) scores. LED refers to the distance between the lesion and the nearest eloquent area (eloquent cortex or eloquent fiber tracts) measured on preoperative fMRI and DTI. Based on logistic regression analysis, the authors constructed 3 new grading systems. The HDVL grading system includes the independent predictors of mRS change (hemorrhagic presentation, diffuseness, deep venous drainage, and LED). Full Score combines the variables in the Spetzler-Martin (S-M) grading system (nidus size, eloquence of adjacent brain, and venous drainage) and the HDVL. For the third grading system, the fS-M grading system, the authors added information regarding eloquent fiber tracts to the S-M grading system. The area under the receiver operating characteristic (ROC) curves was compared with those of the S-M grading system and the supplementary S-M grading system of Lawton et al. RESULTS LED was significantly correlated with a change in mRS score (p < 0.001). An LED of 4.95 mm was the cutoff point for the worsened mRS score. Hemorrhagic presentation, diffuseness, deep venous drainage, and LED were independent predictors of a change in mRS score. Predictive accuracy was highest for the HDVL grading system (area under the ROC curve 0.82), followed by the Full Score grading system (0.80), the fS-M grading system (0.79), the supplementary S-M grading system (0.76), and least for the S-M grading system (0.71). Predictive accuracy of the HDVL grading system was significantly better than that of the Spetzler-Martin grade (p = 0.040). CONCLUSIONS LED was a significant predictor for the preoperative risk evaluation for surgery. The HDVL system was a good predictor of neurological outcomes after BAVM surgery. Adding the consideration of the involvement of eloquent fiber tracts to preoperative evaluation can effectively improve its predictive accuracy.

Morbidity after Hemorrhage in Children with Untreated Brain Arteriovenous Malformation

BACKGROUND

Children with untreated brain arteriovenous malformations (bAVM) are at risk of encountering life-threatening hemorrhage very early in their lives. The primary aim of invasive treatment is to reduce unfavorable outcome associated with a bAVM rupture. A better understanding of the morbidity of bAVM hemorrhage might be helpful for weighing the risks of untreated bAVM and invasive treatment. Our aim was to assess the clinical outcome after bAVM rupture and identify features to predict severe hemorrhage in children.

METHODS

We identified all consecutive children admitted to our institution for bAVMs between July 2009 and December 2014. Clinical outcome after hemorrhagic presentation and subsequent hemorrhage was evaluated using the modified Rankin Scale (mRS) for children. The association of demographic characteristics and bAVM morphology with severe hemorrhage (mRS >3 or requiring emergency hematoma evacuation) was studied using univariate and multivariable regression analyses. A nomogram based on multivariable analysis was formulated to predict severe hemorrhage risk for individual patients.

RESULTS

A total of 134 patients were identified with a mean treatment-free follow-up period of 2.1 years. bAVM ruptured in 83 (62%) children: 82 had a hemorrhage at presentation and 6 of them experienced a recurrent hemorrhage during follow-up; 1 patient had other diagnostic symptoms but bled during follow-up. Among them, 49% (41/83) had a severe hemorrhage; emergency hematoma evacuation was required in 28% of them (23/83), and 24% (20/83) remained as disabled (mRS ≥3) at last follow-up. Forty-six percent (38/82) of children with hemorrhagic presentation were severely disabled (mRS >3). Forty-three percent (3/7) were severely disabled after subsequent hemorrhage. The annual rate of severe subsequent hemorrhage was 1% in the overall cohort and 3.3% in children with ruptured presentation. All the subsequent severe hemorrhage events occurred in children with severe hemorrhage history (7%, 3/41). Periventricular location, non-temporal lobe location, and long draining vein were predictors for severe hemorrhage in pediatric untreated bAVMs. A nomogram based on bAVM morphology was contracted to predict severe hemorrhage risk for individual patients, which was well calibrated and had a good discriminative ability (adjusted C-statistic, 0.72).

CONCLUSIONS

Evaluating bAVM morbidity and morphology might be helpful for weighing the risks of untreated bAVM in pediatric patients.

New predictive model for microsurgical outcome of intracranial arteriovenous malformations: study protocol

INTRODUCTION

Although microsurgical resection is currently the first-line treatment modality for arteriovenous malformations (AVMs), microsurgery of these lesions is complicated due to the fact that they are very heterogeneous vascular anomalies. The Spetzler-Martin grading system and the supplementary grading system have demonstrated excellent performances in predicting the risk of AVM surgery. However, there are currently no predictive models based on multimodal MRI techniques. The purpose of this study is to propose a predictive model based on multimodal MRI techniques to assess the microsurgical risk of intracranial AVMs.

METHODS AND ANALYSIS

The study consists of 2 parts: the first part is to conduct a single-centre retrospective analysis of 201 eligible patients to create a predictive model of AVM surgery based on multimodal functional MRIs (fMRIs); the second part is to validate the efficacy of the predictive model in a prospective multicentre cohort study of 400 eligible patients. Patient characteristics, AVM features and multimodal fMRI data will be collected. The functional status at pretreatment and 6 months after surgery will be analysed using the modified Rankin Scale (mRS) score. The patients in each part of this study will be dichotomised into 2 groups: those with improved or unchanged functional status (a decreased or unchanged mRS 6 months after surgery) and those with worsened functional status (an increased mRS). The first part will determine the risk factors of worsened functional status after surgery and create a predictive model. The second part will validate the predictive model and then a new AVM grading system will be proposed.

ETHICS AND DISSEMINATION

The study protocol and informed consent form have been reviewed and approved by the Institutional Review Board of Beijing Tiantan Hospital Affiliated to Capital Medical University (KY2016-031-01). The results of this study will be disseminated through printed media.

TRIAL REGISTRATION NUMBER

NCT02868008.