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Nan-Xiang Xiong and Hong-Yang Zhao

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Xiaochuan Huo, Yuhua Jiang, Xianli Lv, Hongchao Yang, Yang Zhao, and Youxiang Li

OBJECT

A combination of embolization and radiosurgery is used as a common strategy for the treatment of large and complex cerebral arteriovenous malformations (AVMs). This study presents the experiences of partially embolized cerebral AVMs followed by Gamma Knife surgery (GKS) and assesses predictive factors for AVM obliteration and hemorrhage.

METHODS

The interventional neuroradiology database that was reviewed included 404 patients who underwent AVM embolization. Using this database, the authors retrospectively analyzed all partially embolized AVM cases followed by GKS for a residual nidus. Except for cases of complete AVM obliteration, the authors excluded all patients with radiological follow-up of less than 2 years. Logistic regression analysis was used to analyze the predictive factors related to AVM obliteration and hemorrhage following GKS. Kaplan-Meier analysis was used to evaluate the obliteration with a cutoff AVM nidus volume of 3 cm3 and 10 cm3.

RESULTS

One hundred sixty-two patients qualified for the study. The median patient age was 26 years and 48.8% were female. Hemorrhage presented as the most common symptom (48.1%). The median preembolization volume of an AVM was 14.3 cm3. The median volume and margin dose for GKS were 10.92 cm3 and 16.0 Gy, respectively. The median radiological and clinical follow-up intervals were 47 and 79 months, respectively. The annual hemorrhage rate was 1.71% and total obliteration rate was 56.8%. Noneloquent area (p = 0.004), superficial location (p < 0.001), decreased volume (p < 0.001), lower Spetzler-Martin grade (p < 0.001), lower Virginia Radiosurgery AVM Scale (RAS; p < 0.001), lower Pollock-Flickinger score (p < 0.001), lower modified Pollock-Flickinger score (p < 0.001), increased maximum dose (p < 0.001), and increased margin dose (p < 0.001) were found to be statistically significant in predicting the probability of AVM obliteration in the univariate analysis. In the multivariate analysis, only volume (p = 0.016) was found to be an independent prognostic factor for AVM obliteration. The log-rank (Mantel-Cox) test of the Kaplan-Meier analysis (chi-square = 54.402, p < 0.001) showed a significantly decreased obliteration rate of different cutoff AVM volume groups of less than 3 cm3, 3–10 cm3, and more than 10 cm3. No independent prognostic factor was found for AVM hemorrhage in multivariate analysis.

CONCLUSIONS

Partially embolized AVMs are amenable to successful treatment with GKS. The volume of the nidus significantly influences the outcome of radiosurgical treatment. The Virginia RAS and Pollock-Flickinger score were found to be reliable scoring systems for selection of patient candidates and prediction of partially embolized AVM closure and complications for GKS.

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Chenhao Zhao, Ting Hu, Weilin Kong, De Yang, Junfang Wan, Kefeng Lv, Jiasheng Liao, Zhao Chen, He Jiang, Deping Wu, Ping Yang, Wenjie Zi, Fengli Li, and Qingwu Yang

OBJECTIVE

First-pass effect (FPE), defined as successful reperfusion (modified Thrombolysis in Cerebral Infarction score 2b–3) with a single stent retriever attempt without salvage treatment, has not been fully identified in patients with acute basilar artery occlusion (BAO). The authors’ aim was to assess the impact of FPE on efficacy and safety for patients with BAO.

METHODS

The authors included data from the Acute Basilar Artery Occlusion Study (BASILAR) about patients who underwent mechanical thrombectomy within 24 hours after symptom onset and compared the clinical outcomes of patients who achieved FPE with those who did not. In addition, the authors further compared outcomes between patients with FPE and those with final successful reperfusion achieved with salvage treatment. The primary clinical outcome was favorable outcome (modified Rankin Scale score ≤ 3).

RESULTS

Among 471 enrolled patients, FPE was achieved in 83 (17.6%) who underwent acute BAO thrombectomy. FPE was strongly associated with favorable outcome (adjusted OR 2.84, 95% CI 1.56–5.16, p = 0.001), lower rate of mortality (28.9% of FPE patients vs 48.2% of non-FPE patients, p = 0.001), and shorter median time from groin puncture to recanalization (65 minutes vs 110 minutes, p < 0.001). Occlusion site of the distal basilar artery, cardioembolism, and undetermined etiology were positive predictors of FPE, whereas baseline National Institutes of Health Stroke Scale score was a negative predictor. Compared with final successful reperfusion, FPE also contributed independently to favorable outcomes (adjusted OR 2.25, 95% CI 1.23–4.10, p = 0.008).

CONCLUSIONS

FPE was associated with 90-day favorable outcome in patients with acute BAO who underwent stent retriever thrombectomy within 24 hours.

Clinical trial registration no.: ChiCTR1800014759 (www.chictr.org.cn)

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Zhe-Feng Zhao, Li-Zhuang Yang, Chuan-Lu Jiang, Yong-Ri Zheng, and Jin-Wei Zhang

Object

The authors' goal was to observe histopathological changes in the trigeminal nerve after Gamma Knife surgery (GKS) in rhesus monkeys, and to investigate the radiobiological mechanism of GKS for primary trigeminal neuralgia. The nerve length–dosage effect of irradiation is also discussed.

Methods

One of 5 rhesus monkeys randomly served as a control, and the other 4 monkeys were randomly administered a target radiation dose of 60, 70, 80, or 100 Gy (a different dose in each animal). The size of the collimator was 4 mm, and the target point was the trigeminal nerve root. In each experimental monkey, one side was exposed to single-target-point irradiation, and the contralateral side was exposed to double-target-point irradiation. After 6 months, the trigeminal nerve root was examined using light microscopy, transmission electron microscopy, and immunohistochemistry.

Results

At each radiation dose, the damage to the nerve tissue by single-target-point irradiation was identical to that caused by double-target-point irradiation. In the trigeminal nerve tissues of the monkeys irradiated with 60 and 70 Gy, there was limited nerve demyelination and degeneration, fragmentation, or loss of axons. In the trigeminal nerve tissue of the monkey irradiated with 80 Gy, the nerve tissue showed a disordered structure. In the trigeminal nerve tissue of the monkey irradiated with 100 Gy, there was severe derangement in the structure of the nerve tissue, and extensive demyelination, fragmentation, and loss of axons.

Conclusions

The target doses of 60 and 70 Gy have very little impact on the structure of the trigeminal nerve. Irradiation at 80 Gy can cause partial degeneration and loss of axons and demyelination. A 100-Gy dose can cause some necrosis of neurons. Comparing the single-target-point with the double-target-point irradiation, the extent of damage to the nerve tissue is identical, and no difference in the nerve length–dosage effect was found.

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Yongxu Wei, Wenlei Yang, Weiguo Zhao, Chunhua Pu, Ning Li, Yu Cai, and Hanbing Shang

OBJECTIVE

The purpose of this study was to evaluate whether intraoperative monitoring of lateral spread response (LSR) improves the efficacy of microvascular decompression (MVD) for hemifacial spasm (HFS).

METHODS

In this prospective study, patients undergoing MVD for HFS were assigned to one of 2 groups, Group A (MVD with intraoperative LSR monitoring) or Group B (MVD without LSR monitoring). Clinical outcome at 12 months after surgery was assessed through telephone survey. Data analysis was performed to investigate the effect of intraoperative LSR monitoring on efficacy of MVD.

RESULTS

A total of 283 patients were enrolled in the study, 145 in Group A and 138 in Group B. There was no statistically significant difference between the 2 groups with respect to the percentage of patients who had spasm relief at either 1 week (Group A 87.59% vs Group B 83.33%; p = 0.317) or 1 year (93.1% vs 94.2%; p = 0.809) after surgery. A clear-cut elimination of LSR during surgery was observed in 131 (90.34%) of 145 patients; LSR persisted in 14 patients (9.66%) at the end of the surgical procedure. Disappearance of LSR correlated with spasm-free status at 1 week postoperatively (p = 0.017) but not at 1 year postoperatively (p = 0.249).

CONCLUSIONS

Intraoperative LSR monitoring does not appear to provide significant benefit with respect to the outcome of MVD for HFS in skilled hands. Persistence of LSR does not always correlate with poor outcome, and LSR elimination should not be pursued in all patients after verification of complete decompression.

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Jingjian Ma, Tianqiang Song, Wang Hu, Michael Edgar Muhumuza, Wenping Zhao, Shuyuan Yang, Jingwen Bai, and Haixian Yang

Object

The authors conducted a study to develop a safe and effective intracranial venous sinus reconstruction for extensive clinical use.

Methods

After resecting the superior sagittal sinus (SSS), it was reconstructed in eight dogs by performing either a tube-insertion technique or end-to-end anastomosis procedure, in both of which a thin-walled silicone tube was used for repair. The patency of the SSS reconstruction was observed on digital subtraction angiography and transcranial Doppler ultrasonography, preoperatively and at 1, 2, 4, and 8 weeks postoperatively. Histological and ultrastructural changes were observed using light and electron microscopy.

In five dogs the reconstructed SSS was patent, in one it was narrowed, in one it was completely occluded at the proximal site of the anastomosis, and one dog escaped from the laboratory 1 week postoperatively. The authors found no evidence of any additional neurological deficits, signs of toxicity, or side effects. Histological and ultrastructural studies generally showed vascular endothelial proliferation. No thrombosis occurred in the inner surface, at the site of anastomosis, or in the lumen of silicone tube nor in the sagittal sinus at up to 8 weeks postoperatively.

Conclusions

The use of a thin-walled silicone tube as an artificial substitute for intracranial dural venous sinus reconstruction seems to be a valuable technique. The silicone tubes were found to have good biological compatibility, nonthrombogenic effects, and a high patency rate. The method was found to be simple and effective as well as practicable in the clinic for the short term (8 weeks). The authors emphasize that Phase I clinical trials involving silicone tube–assisted SSS reconstruction require further research.

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Peng Li, Fu Zhao, Jing Zhang, Zhenmin Wang, Xingchao Wang, Bo Wang, Zhijun Yang, Jun Yang, Zhixian Gao, and Pinan Liu

OBJECT

The aim of this study was to evaluate the clinical features of spinal schwannomas in patients with schwannomatosis and compare them with a large cohort of patients with solitary schwannomas and neurofibromatosis Type 2 (NF2).

METHODS

The study was a retrospective review of 831 patients with solitary schwannomas, 65 with schwannomatosis, and 102 with NF2. The clinical, radiographic, and pathological data were extracted with specific attention to the age at onset, location of tumors, initial symptoms, family history, and treatment outcome.

RESULTS

The male-to-female ratio of patients with schwannomatosis (72.3% vs 27.7%) was significantly higher than that of patients with solitary schwannomas (53.3% vs 46.7%) and NF2 (54.0% vs 46.0%), respectively (chi-square test, p = 0.012). The mean age at the first spinal schwannoma operation of patients with NF2 (24.7 ± 10.2 years) was significantly younger than that of patients with solitary schwannomas (44.8 ± 13.2 years) and schwannomatosis (44.4 ± 14.1 years; 1-way ANOVA, p < 0.001). The initial symptoms were similar among the 3 groups, with pain being the most common. The distribution of spinal tumors among the 3 groups was significantly different. The peak locations of spinal schwannomas in patients with solitary schwannomas were at C1–3 and T12–L3; in schwannomatosis, the peak location was at T12-L5. A preferred spinal location was not evident for intradural-extramedullary tumors in NF2. Only a slight prominence in the lumbar area could be observed. The patients in the 3 groups obtained similar benefits from the operation; the recovery rates in the patients with solitary schwannomas, NF2, and schwannomatosis were 50.1%, 38.0%, and 53.9%, respectively. The prognosis varied among spinal schwannomas in the patients with schwannomatosis. Up until the last date of follow-up, most patients with schwannomatosis (81.5%) had undergone a single spinal operation, but 12 patients (18.5%) had undergone multiple spinal operations. Patients with nonsegmental schwannomatosis or those with early onset disease seemed to have a poor prognosis; they were more likely to undergo multiple spinal operations. Small cauda equina nodules were common in patients with schwannomatosis (46.7%) and NF2 (86.9%); these small schwannomas appeared to have relatively static behavior. Two patients suspicious for schwannomatosis were diagnosed with NF2 with the detection of constitutional NF2 mutations; 1 had unilateral vestibular schwannoma, and the other had suspicious bilateral trigeminal schwannomas.

CONCLUSIONS

The clinical features of spinal schwannomas vary among patients with solitary schwannomas, NF2, and schwannomatosis. Spinal schwannomas of patients with NF2 appear to be more aggressive than those in patients with solitary schwannomas and schwannomatosis. Spinal schwannomas of schwannomatosis predominate in the lumbar area, and most of them can be treated successfully with surgery. The prognosis varies among spinal schwannomas of schwannomatosis; some patients may need multiple operations due to newly developed schwannomas. Sometimes, it is difficult to differentiate schwannomatosis from NF2 based on clinical manifestations. It is prudent to perform close follow-up examinations in patients with undetermined schwannomatosis and their offspring.

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Xiaofeng Deng, Kai Wang, Liang Wu, Chenlong Yang, Tao Yang, Lei Zhao, Jun Yang, Guihuai Wang, Jingyi Fang, and Yulun Xu

Object

Intraspinal hemangioblastomas are relatively uncommon benign tumors. The surgical strategies remain controversial, and the risk factors with regard to clinical outcome are unclear. The purpose of this study was to analyze the clinical characteristics, imaging findings, surgical strategies, and functional outcomes associated with intraspinal hemangioblastomas.

Methods

A series of 92 patients who underwent 102 operations for resection of 116 intraspinal hemangioblastomas at a single institution during 2007–2011 were consecutively enrolled in this study. Of these, 60 patients (65.2%) had sporadic hemangioblastomas and 32 (34.8%) had von Hippel-Lindau disease. Preoperatively, 13 patients underwent digital subtraction angiography (DSA), 15 patients underwent 3D CT angiography (3D CTA), and none underwent preoperative embolization. Clinical characteristics, imaging findings, and operative records were analyzed. The advantages and disadvantages of DSA and 3D CTA were compared. For identification of risk factors that affect prognosis, logistic analysis was performed.

Results

The male/female patient ratio was 1.8:1.0 (59 male and 33 female patients). Of the tumors, 41% were intramedullary, 37% were intramedullary-extramedullary, and 22% were primarily extramedullary. Three-dimensional CTA and DSA did not differ significantly in the ability to identify the feeding arteries (p = 1.000) and image qualities (p = 0.367). However, compared with 3D CTA, the effective x-ray dose of spinal DSA was 2.73 times higher and the mean amount of contrast media injected was 1.88 times higher. Spinal DSA was more time consuming (mean 120 minutes) than 3D CTA (scanning time < 1 minute). No complications were observed after 3D CTA; acute paraparesis developed in 1 patient after DSA.

Gross-total resection was achieved for 109 tumors (94.0%), and resection was subtotal for 7 tumors. Mean duration of follow-up was 50 months (range 24–78 months). At the most recent follow-up visit, the functional outcome was improved for 38 patients (41.3%), remained stable for 40 (43.5%), and deteriorated for 14 (15.2%). Logistic analysis showed that subtotal resection was a risk factor affecting prognosis (p = 0.003, OR 12.833, 95% CI 2.429–67.806).

Conclusions

The authors' study suggests that safe and effective treatment of intraspinal hemangioblastomas can be achieved for most patients, even without preoperative embolization. Gross-total resection, when safe to perform, leads to better outcomes. Compared with spinal DSA, 3D CTA is a promising technique because it is noninvasive, takes less time to perform, requires lower x-ray doses and less contrast media, results in fewer complications, and offers high accuracy for delineating the feeding arteries.

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Liang Wu, Tao Yang, Xiaofeng Deng, Chenlong Yang, Lei Zhao, Ning Yao, Jingyi Fang, Guihuai Wang, Jun Yang, and Yulun Xu

Object

Extradural en plaque meningiomas are very rare tumors in the spinal canal. Most studies on these lesions have been case reports with literature reviews. In this paper, the authors review their experience in a surgical series of 12 patients with histologically proven, purely extradural en plaque meningiomas and discuss their clinical features, radiological findings, and long-term outcomes.

Methods

Clinical and imaging data of 12 patients with spinal extradural en plaque meningiomas treated at a single institution were retrospectively analyzed.

Results

There were 5 male and 7 female patients, with a mean age of 39.9 years. The mean follow-up period was 74.8 months. Nine tumors were located in the cervical spine, 1 in the cervicothoracic spine, and 2 in the thoracic spine. All the tumors were confirmed as extradural en plaque meningiomas with sheetlike growth along the dura mater. Gross-total resection of the tumor with a well-demarcated dissection plane was achieved in 4 cases. Subtotal resection was achieved in 8 cases, 2 of whom underwent postoperative low-dose radiation therapy. The symptoms present before the surgery were improved in all cases at the last follow-up evaluation. The postoperative follow-up MRI showed no recurrence or regrowth in 4 cases with gross-total removal and 7 cases with subtotal removal during the mean follow-up periods of 58.0 months and 71.1 months, respectively. One patient experienced recurrence at 88 months after his initial subtotal removal and improved following a revision operation.

Conclusions

Spinal extradural en plaque meningiomas are amenable to surgery if complete removal can be achieved. Because of the encirclement of the dura that is characteristic of the tumors, complete resection is usually difficult, subtotal removal for spinal cord decompression is advised, and follow-up imaging is needed. The risk of long-term recurrence/regrowth of the lesions is low, and a good clinical outcome after total or subtotal removal can be expected.

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Haitao Ju, Xin Li, Hong Li, Xiaojuan Wang, Hongwei Wang, Yang Li, Changwu Dou, and Gang Zhao

Object

Signal transducer and activator of transcription 1 (STAT1) is thought to be a tumor suppressor protein. The authors investigated the expression and role of STAT1 in glioblastoma.

Methods

Immunohistochemistry was used to detect the expression of STAT1 in glioblastoma and normal brain tissues. Reverse transcription–polymerase chain reaction and Western blot analysis were used to detect mRNA and protein expression levels of STAT1. Cell growth, proliferation, migration, apoptosis, and the expression of related genes and proteins (Bcl-2, Bax, cleaved caspase-3, caspase-9, p21, and proliferating cell nuclear antigen) were examined in vitro via cell counting kit-8, wound-healing, flow cytometry, Rhodamine B, TUNEL, and Western blot assays.

Results

Human glioblastoma had decreased expression of STAT1 proteins. Transfection of the U87MG cells with STAT1 plasmid in vitro demonstrated significant inhibition of cell growth and an increase in apoptotic cell death compared with cells transfected with vector or mock plasmids. These effects were associated with the upregulation of cleaved caspase-3, Bax, and p21 and the downregulation of Bcl-2 expression.

Conclusions

The results of this study suggest that increased expression of STAT1 by transfection with STAT1 plasmid synergistically inhibits human U87MG glioblastoma cell growth in vitro.