title: Risk factors for worsened muscle strength after the surgical treatment of arteriovenous malformations of the eloquent motor area.
abstract: OBJECT 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-to-activation 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 in these patients should be carefully considered. In patients with an LCD > 5 mm, radical resection may be considered to eliminate the risk of hemorrhage.
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University;|China National Clinical Research Center for Neurological Diseases;|Center of Stroke, Beijing Institute for Brain Disorders;|Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease;
authors.forename: Fuxin
authors.initials: F
authors.lastname: Lin
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University;|China National Clinical Research Center for Neurological Diseases;|Center of Stroke, Beijing Institute for Brain Disorders;|Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease;
authors.forename: Bing
authors.initials: B
authors.lastname: Zhao
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University;|China National Clinical Research Center for Neurological Diseases;|Center of Stroke, Beijing Institute for Brain Disorders;|Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease;
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Neurosurgery, Hongqi Hospital, Mu Dan Jiang Medical University, Mu Dan Jiang, Hei Long Jiang Province, People's Republic of China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Wang
authors.affiliation: Medical Imaging Center, The 306th Hospital of PLA, Beijing; and.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University;|China National Clinical Research Center for Neurological Diseases;|Center of Stroke, Beijing Institute for Brain Disorders;|Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease;
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University;|China National Clinical Research Center for Neurological Diseases;|Center of Stroke, Beijing Institute for Brain Disorders;|Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease;
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000098:blood supply*; D053580:Muscle Strength; D011183:Postoperative Complications / Q000503:physiopathology*; D012189:Retrospective Studies; D012307:Risk Factors; D014656:Vascular Surgical Procedures / Q000379:methods; D055815:Young Adult
keywords: 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; LAD = lesion-to–activation area distance; LCD = lesion-to-CST distance; MS = preoperative muscle strength; MS1 = muscle strength 1 week postoperatively; MS2 = 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; cerebral arteriovenous malformations; diffusion tensor imaging; fMRI = functional MRI; functional magnetic resonance imaging; motor function; risk factor; surgery