A Supplementary Grading Scale for Selecting Patients With Brain Arteriovenous Malformations for Surgery

Lawton, Michael T.; Kim, Helen; McCulloch, Charles E.; Mikhak, Bahar; Young, William L.

doi:10.1227/01.neu.0000367555.16733.e1

Cited by 385 publications

(303 citation statements)

References 19 publications

(27 reference statements)

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“…13,18,38 Embolization of the AVM still has limited curative potential and can add to total management-related morbidity. 12,26,28,36 The goals of SRS include AVM obliteration, preservation of neurological function, and minimization of risk.…”

Section: Discussionmentioning

confidence: 99%

Stereotactic radiosurgery for arteriovenous malformations, Part 2: management of pediatric patients

Kano

Kondziolka

Flickinger

et al. 2012

PED

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Object The authors conducted a study to define the long-term outcomes and risks of stereotactic radiosurgery (SRS) for pediatric arteriovenous malformations (AVMs). Methods Between 1987 and 2006, the authors performed Gamma Knife surgery in 996 patients with brain AVMs; 135 patients were younger than 18 years of age. The median maximum diameter and target volumes were 2.0 cm (range 0.6–5.2 cm) and 2.5 cm3 (range 0.1–17.5 cm3), respectively. The median margin dose was 20 Gy (range 15–25 Gy). Results The actuarial rates of total obliteration documented by angiography or MR imaging at 71.3 months (range 6–264 months) were 45%, 64%, 67%, and 72% at 3, 4, 5, and 10 years, respectively. The median time to complete angiographically documented obliteration was 48.9 months. Of 81 patients with 4 or more years of follow-up, 57 patients (70%) had total obliteration documented by angiography. Factors associated with a higher rate of documented AVM obliteration were smaller AVM target volume, smaller maximum diameter, and larger margin dose. In 8 patients (6%) a hemorrhage occurred during the latency interval, and 1 patient died. The rates of AVM hemorrhage after SRS were 0%, 1.6%, 2.4%, 5.5%, and 10.0% at 1, 2, 3, 5, and 10 years, respectively. The overall annual hemorrhage rate was 1.8%. Larger volume AVMs were associated with a significantly higher risk of hemorrhage after SRS. Permanent neurological deficits due to adverse radiation effects developed in 2 patients (1.5%) after SRS, and in 1 patient (0.7%) delayed cyst formation occurred. Conclusions Stereotactic radiosurgery is a gradually effective and relatively safe management option for pediatric patients in whom surgery is considered to pose excessive risks. Although hemorrhage after AVM obliteration did not occur in the present series, patients remain at risk during the latency interval until obliteration is complete. The best candidates for SRS are pediatric patients with smaller volume AVMs located in critical brain regions.

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Section: Discussionmentioning

confidence: 99%

Stereotactic radiosurgery for arteriovenous malformations, Part 2: management of pediatric patients

Kano

Kondziolka

Flickinger

et al. 2012

PED

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“…Angioarchitectural variables for each AVM such as size, diffuseness, feeding artery from perforating arteries (FAPAs), deep draining veins, and Spetzler-Martin (SM) grade were determined from preoperative angiograms and MRI scans. 23 Functional variables were measured depending on the location of the vascular lesion. The function with its activated areas closer to the lesion was selected (contralateral hand or foot).…”

Section: Data Collection and Definitionmentioning

confidence: 99%

“…9 Therefore, identifying AVMs in eloquent motor areas that can be safely resected becomes a priority. Although Spetzler and Martin 28 and Lawton et al 23 have proposed grading systems to estimate the risk of surgery based on architectural features, case selection for the surgical treatment of eloquent motor area AVMs remains difficult. Case selection for surgery depends on a sophisticated understating of the angioarchitecture and relationships to surrounding eloquent brain structures.…”

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confidence: 99%

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

Lin

Zhao

et al. 2016

JNS

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abbreviatioNs AUC = area under the ROC curve; AVM = arteriovenous malformation; BOLD = blood oxygen level-dependent; CST = corticospinal tract; DSA = digital subtraction angiography; DTI = diffusion tensor imaging; DW = diffusion weighted; EPI = echo-planar imaging; FA = fractional anisotropy; FAPA = feeding artery from perforating artery; fMRI = functional MRI; LAD = lesion-to-activation area distance; LCD = lesion-to-CST distance; MS = preoperative muscle strength; MS 1 = muscle strength 1 week postoperatively; MS 2 = muscle strength 6 months postoperatively; NPPB = normal perfusion pressure breakthrough; ROC = receiver operating characteristic; ROI = region of interest; SM = Spetzler-Martin; TOF = time-of-flight. obJective Case selection for the surgical treatment of arteriovenous malformations (AVMs) of the eloquent motor area remains challenging. The aim of this study was to determine the risk factors for worsened muscle strength after surgery in patients with this disorder. methods At their hospital the authors retrospectively studied 48 consecutive patients with AVMs involving motor cortex and/or the descending pathway. All patients had undergone preoperative functional MRI (fMRI) and diffusion tensor imaging (DTI), followed by resection. Both functional and angioarchitectural factors were analyzed with respect to the change in muscle strength. Functional factors included lesion-to-corticospinal tract distance (LCD) on DTI and lesion-toactivation area distance (LAD) and cortical reorganization on fMRI. Based on preoperative muscle strength, the changes in muscle strength at 1 week and 6 months after surgery were defined as short-term and long-term surgical outcomes, respectively. Statistical analysis was performed using the statistical package SPSS (version 20.0.0, IBM Corp.). results Twenty-one patients (43.8%) had worsened muscle strength 1 week after surgery. However, only 10 patients (20.8%) suffered from muscle strength worsening 6 months after surgery. The LCD was significantly correlated with short-term (p < 0.001) and long-term (p < 0.001) surgical outcomes. For long-term outcomes, patients in the 5 mm ≥ LCD > 0 mm (p = 0.009) and LCD > 5 mm (p < 0.001) categories were significantly associated with a lower risk of permanent motor worsening in comparison with patients in the LCD = 0 mm group. No significant difference was found between patients in the 5 mm ≥ LCD > 0 mm group and LCD > 5 mm group (p = 0.116). Nidus size was the other significant predictor of short-term (p = 0.021) and long-term (p = 0.016) outcomes. For long-term outcomes, the area under the ROC curve (AUC) was 0.728, and the cutoff point was 3.6 cm. Spetzler-Martin grade was not associated with short-term surgical outcomes (0.143), although it was correlated with long-term outcomes (0.038). coNclusioNs An AVM with a nidus in contact with tracked eloquent fibers (LCD = 0) and having a large size is more likely to be associated with worsened muscle strength after surgery in patients with eloquent motor area AVMs. Surgical treatment i...

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“…8 Lawton et al developed a grading system to predict neurological outcomes after surgery for brain arteriovenous malformations with the aim of improving and refining patient selection. 25 To the best of our knowledge, similar studies are lacking in neurooncological surgery, and the Milan Complexity Scale is the first scale to be created ad hoc for neurooncology. The classifications of complications were based on etiology and the required treatment 23 and useful for data analysis.…”

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confidence: 99%

Predicting functional impairment in brain tumor surgery: the Big Five and the Milan Complexity Scale

Ferroli¹,

Broggi²,

Schiavolin³

et al. 2015

FOC

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OBJECT The Milan Complexity Scale—a new practical grading scale designed to estimate the risk of neurological clinical worsening after performing surgery for tumor removal—is presented. METHODS A retrospective study was conducted on all elective consecutive surgical procedures for tumor resection between January 2012 and December 2014 at the Second Division of Neurosurgery at Fondazione IRCCS Istituto Neurologico Carlo Besta of Milan. A prospective database dedicated to reporting complications and all clinical and radiological data was retrospectively reviewed. The Karnofsky Performance Scale (KPS) was used to classify each patient’s health status. Complications were divided into major and minor and recorded based on etiology and required treatment. A logistic regression model was used to identify possible predictors of clinical worsening after surgery in terms of changes between the preoperative and discharge KPS scores. Statistically significant predictors were rated based on their odds ratios in order to build an ad hoc complexity scale. For each patient, a corresponding total score was calculated, and ANOVA was performed to compare the mean total scores between the improved/unchanged and worsened patients. Relative risk (RR) and chi-square statistics were employed to provide the risk of worsening after surgery for each total score. RESULTS The case series was composed of 746 patients (53.2% female; mean age 51.3 ± 17.1). The most common tumors were meningiomas (28.6%) and glioblastomas (24.1%). The mortality rate was 0.94%, the major complication rate was 9.1%, and the minor complication rate was 32.6%. Of 746 patients, 523 (70.1%) patients improved or remained unchanged, and 223 (29.9%) patients worsened. The following factors were found to be statistically significant predictors of the change in KPS scores: tumor size larger than 4 cm, cranial nerve manipulation, major brain vessel manipulation, posterior fossa location, and eloquent area involvement (Nagelkerke R2 = 0.286). A grading scale was obtained with scores ranging between 0 and 8. Worsened patients showed mean total scores that were significantly higher than the improved/unchanged scores (3.24 ± 1.55 vs 1.47 ± 1.58; p < 0.001). Finally, a grid was developed to show the risk of worsening after surgery for each total score: scores higher than 3 are suggestive of worse clinical outcome. CONCLUSIONS Through the evaluation of the 5 aforementioned parameters—the Big Five—the Milan Complexity Scale enables neurosurgeons to estimate the risk of a negative clinical course after brain tumor surgery and share these data with the patient. Furthermore, the Milan Complexity Scale could be used for research and educational purposes and better health system management.

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A Supplementary Grading Scale for Selecting Patients With Brain Arteriovenous Malformations for Surgery

Cited by 385 publications

References 19 publications

Stereotactic radiosurgery for arteriovenous malformations, Part 2: management of pediatric patients

Stereotactic radiosurgery for arteriovenous malformations, Part 2: management of pediatric patients

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

Predicting functional impairment in brain tumor surgery: the Big Five and the Milan Complexity Scale

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