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Yuxiang Cai, Yanjin Wang and Zhiquan Yang

Dysembryoplastic neuroepithelial tumors (DNETs) are benign intracranial tumors of neuroglial origin, mostly located in the supratentorial regions and particularly in the temporal lobe. Few cases of DNETs in the hypothalamus have been described. The authors present the case of a DNET in the hypothalamus. The 5-year-old girl with complaints of limb and gelastic seizures was admitted to the neurosurgical department of Xiangya Hospital. Neurological examination findings were unremarkable. MRI showed isointensity without significant enhancement on T1- and T2-weighted images. The lesion exhibited clearly defined borders on the sagittal, coronal, and axial images. The preliminary diagnosis was hypothalamic hamartoma (HH); however, the lesion was surgically removed, and histopathological examination confirmed the diagnosis of a DNET. Hypothalamic DNETs are extremely rare. Based on their clinical manifestation and imaging, DNETs are easily misdiagnosed as HHs. Diagnoses apart from HHs must be entertained when a hypothalamic lesion is being investigated.

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Tao Hong, Yang Wang, Hai-tao Wang and Huan Wang

Object

The gap junction is important in the propagation of dilation/constriction signals along vessels for coordinated behavior in control of vascular tone. The authors hypothesized that gap junctions might play a role in cerebral vasospasm following subarachnoid hemorrhage (SAH). The aims of the present study were to investigate the role of gap junctions and to observe the potential therapeutic efficacy of gap junction blockers in cerebral vasospasm in vitro and in vivo.

Methods

For the in vitro investigation, the effect of heptanol on the oxyhemoglobin (HbO2)-induced contraction of isolated rabbit basilar arteries (BAs) was observed by using an isometric tension-recording method. For the in vivo experiments, the potential therapeutic efficacy of heptanol and carbenoxolone was surveyed after it was given intravenously in the rabbit double-hemorrhage model. Light microscopy was performed to assess the morphological changes in the arteries examined.

Results

For the in vitro method, heptanol significantly inhibited the sustained contraction induced both by HbO2 and K+ in the BA rings. The magnitude of the heptanol-induced relaxation was dose dependent. The inhibitory effect of heptanol on the K+-induced vasoconstriction was weaker than that on the HbO2-induced constriction. After arterial rings were pretreated for 10 minutes, heptanol significantly decreased their responses to the HbO2-induced contraction. For the in vivo method, heptanol and carbenoxolone significantly decreased the narrowing of BAs when given intravenously in the rabbit double-hemorrhage model. In both treated groups, the diameters of the arteries had not changed significantly on Day 7 compared with those of the arteries in the SAH + vehicle and the SAH-only group.

Conclusions

Heptanol and carbenoxolone significantly inhibited the experimental cerebral vasospasm both in vitro and in vivo. Blockage of gap junctions is a probable candidate for a new approach in the treatment of cerebral vasospasm. Gap junctions may play a pathophysiological role in cerebral vasospasm.

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Weijun Peng, Zhihua Xing, Jingjing Yang, Yang Wang, Weihao Wang and Wei Huang

Object

Erythropoietin (EPO) shows promise as a neuroprotective agent in animal models of traumatic brain injury (TBI). However, clinical trials of the efficacy of EPO treatment in patients with TBI yield conflicting results. The authors conducted a systematic review and meta-analysis to assess the effect of EPO in experimental animal models of TBI, the goal being to inform the design of future clinical trials.

Methods

The authors identified eligible studies by searching PubMed, Web of Science, MEDLINE, Embase, and Google Scholar in October 2013. Data were pooled using the random-effects model, and results were reported in terms of standardized mean difference. Statistical heterogeneity was examined using both I2 and chi-square tests, and the presence of small study effects was investigated with funnel plots and Egger tests. In-depth analyses were performed for lesion volume and neurobehavioral outcome, and the studies' methodological quality was also evaluated.

Results

Of a total of 290 studies, 13 found an effect of EPO on lesion volume and neurobehavioral outcome. Overall, the methodological quality of the studies was poor, and there was evidence of statistical heterogeneity among the publications as well as small-study effects. However, in-depth analyses showed statistically significant findings in favor of a beneficial effect of EPO after TBI.

Conclusions

Despite limitations of this systematic review that may have influenced the findings, the authors conclude that EPO might be beneficial in treating experimental TBI in terms of reducing lesion volume and improving neurobehavioral outcome. However, this review also indicates that more well-designed and well-reported animal studies are needed.

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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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J. J. Verlaan and F. C. Oner

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Xiang-Yang Wang, Li-Yang Dai, Hua-Zi Xu and Yong-Long Chi

Object.

Experimental burst fracture models are often developed by using either single or incremental impacts. In both protocols, the weight-drop technique produces the impact. However, to the authors' knowledge in no study have researchers attempted to compare the equivalence of the spine burst fracture produced using the different impact protocols. This study was performed to investigate whether the single and incremental trauma approaches produce equivalent degrees of severity in thoracolumbar burst fractures.

Methods.

Twenty bovine thoracolumbar spines comprising three vertebrae were divided evenly into the single impact and incremental impact groups. The specimens in the incremental impact group were subjected to three axial compressive impacts of increasing energy (78.4, 107.8, and 137.2 J), whereas specimens in the other group were subjected to a single impact (137.2 J). Before and after the final trauma, multidirectional flexibility of each specimen was measured under flexion/extension, right/left lateral bending, and right/left axial rotation, thus quantifying the instability of the fracture. The flexibility parameters were then compared between the two groups.

Results.

A significant increase in flexibility parameters was found after the final trauma in both groups, indicating the instability of the spine (p < 0.01). No significant differences in flexibility parameters were observed in either intact status or injured status between the two groups (p > 0.05).

Conclusions.

In this study the authors have confirmed that the single and incremental impact protocols produced a similar degree of severity in producing an in vitro bovine burst fracture. The results of this study support the use of the incremental impact protocol in future experimental biomechanical studies.

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Xiang-Yang Wang, Li-Yang Dai, Hua-Zi Xu and Yong-Long Chi

Object

Recurrent kyphosis has been commonly seen after posterior short-segment pedicle instrumentation for a thoracolumbar fracture, but studies on this issue are relatively scarce, and the clinical significance of recurrent deformity is uncertain. No study has addressed the associations between the reduction of a burst fracture vertebra and the final recurrent kyphosis after implant removal. The aim of this study was to investigate the recurrent kyphosis after short-segment pedicle screw fixation in thoracolumbar burst fractures and to evaluate the effect of the degree of a vertebral reduction on the recurrent kyphotic deformity after implant removal.

Methods

Twenty-seven patients who had undergone posterior short-segment pedicle screw fixation for thoracolumbar junction burst fractures (T12–L2) were investigated retrospectively. The minimum follow-up period was 2 years (mean 2.7 years). Pain status was evaluated using the Denis pain scale. Changes in the anterior vertebral height ratio, vertebral wedge angle, upper intervertebral angle, lower intervertebral angle, Cobb angle, regional angle, and sagittal index were measured preoperatively, postoperatively, before implant removal, and at final follow-up. The correlation between the reduction of a fractured vertebra and the recurrent kyphotic deformity was also analyzed.

Results

After the initial surgical correction, the reduced vertebral body (VB) height (anterior vertebral height ratio and vertebral wedge angle) remained stable until final follow-up, whereas the intervertebral disc space (the upper and lower intervertebral angles) collapsed, resulting in a progressive kyphotic deformity (Cobb angle, regional angle, and sagittal index). No significant correlation was found between the final kyphosis and pain scale, but the 8 patients with a sagittal index > 15° showed a higher incidence of moderate to severe pain (P3–5 on the Denis pain scale) compared with the remaining 19 patients with a sagittal index < 15°. Significant positive correlation was found between recurrent kyphosis and vertebral wedge angle (r = 0.850, p < 0.001) and the reduced vertebral height (r = −0.727, p < 0.001).

Conclusions

Given that the correction loss occurs primarily through disc space collapse, the amount of the final kyphotic deformity was predictable by the degree of the fractured vertebral reduction as seen on the lateral x-ray study. Surgeons who perform posterior reduction and fixation procedures should pay more attention to reducing the fractured vertebral wedge angle to its intact condition, rather than the segmental angular parameters. If the wedge angle of the fractured VB is unacceptable after reduction, additional reconstruction of the anterior column may be necessary.

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Yang Li, Xinxin Yuan, Shifu Sha, Zhen Liu, Weiguo Zhu, Yong Qiu, Bin Wang, Yang Yu and Zezhang Zhu

OBJECTIVE

The aim of this study was to investigate how implant density affects radiographic results and clinical outcomes in patients with dystrophic scoliosis secondary to neurofibromatosis Type 1 (NF1).

METHODS

A total of 41 patients with dystrophic scoliosis secondary to NF1 who underwent 1-stage posterior correction between June 2011 and December 2013 were included. General information about patients was recorded, as were preoperative and postoperative scores from Scoliosis Research Society (SRS)–22 questionnaires. Pearson correlation analysis was used to analyze the associations among implant density, coronal Cobb angle correction rate and correction loss at last follow-up, change of sagittal curve, and apical vertebral translation. Patients were then divided into 2 groups: those with low-density and those with high-density implants. Independent-sample t-tests were used to compare demographic data, radiographic findings, and clinical outcomes before surgery and at last follow-up between the groups.

RESULTS

Significant correlations were found between the implant density and the coronal correction rate of the main curve (r = 0.505, p < 0.01) and the coronal correction loss at final follow-up (r = −0.379, p = 0.015). There was no significant correlation between implant density and change of sagittal profile (p = 0.662) or apical vertebral translation (p = 0.062). The SRS-22 scores improved in the appearance, activity, and mental health domains within both groups, but there was no difference between the groups in any of the SRS-22 domains at final follow-up (p > 0.05 for all).

CONCLUSIONS

Although no significant differences between the high- and low-density groups were found in any of the SRS-22 domains at final follow-up, higher implant density was correlated with superior coronal correction and less postoperative correction loss in patients with dystrophic NF1-associated scoliosis.

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Yanbin Zhang, Qifeng Peng, Shengru Wang, Yang Yang, Guanfeng Lin and Jianguo Zhang

OBJECTIVE

Concerns remain over the influence of pedicle screw instrumentation on the growth potential of an immature spine. Previous studies have reported discrepancies between animal experiments and clinical studies. The authors’ objective was to explore the influence of pedicle screw instrumentation on the growth of an immature spine at a very young age.

METHODS

Individuals who met the authors’ criteria were included. Anteroposterior diameter of the vertebral body; pedicle length on both sides; and anteroposterior diameter, transverse diameter, and area of the spinal canal were measured on CT images before surgery and at the final follow-up. Parameters of instrumented vertebrae and adjacent noninstrumented vertebrae were compared. The growth value and growth percentage of each parameter were calculated. Subgroup comparisons were made in thoracic vertebrae and lumbar vertebrae. Statistical analyses were performed.

RESULTS

Thirteen patients with a congenital spinal deformity were included in the study. The average age at surgery was 3.4 (range 2–5) years, and the average follow-up was 7.2 (range 5–11) years. Osteotomy and short instrumentation with pedicle screws were performed in each case. A total of 69 segments were measured, including 43 instrumented vertebrae and 26 immediately adjacent noninstrumented vertebrae. Significant increases in all parameters were noted at the final follow-up. In instrumented vertebrae, growth of the pedicle length and the anteroposterior diameter and area of the spinal canal increased significantly, while growth of the anteroposterior diameter of the vertebral body decreased significantly compared with noninstrumented vertebrae. Similar results were noted in the lumbar region. The shape-change phenomenon was found in noninstrumented vertebrae but was not apparent in instrumented vertebrae.

CONCLUSIONS

Pedicle screw instrumentation may slow down growth of the vertebral body, indirectly speed up growth of the spinal canal, and hinder the shape-change phenomenon of the lumbar spinal canal. However, the influences were quite slight, and significant development did occur in instrumented vertebrae. Therefore, pedicle screw instrumentation may not have much effect on the growth of immature vertebrae in children younger than 5 years.

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Zhijun Yang, Bo Wang, Chungcheng Wang and Pinan Liu

Object

The authors aim to identify the characteristics of primary spontaneous CSF rhinorrhea and propose a hypothesis for its pathogenesis.

Methods

Between 2003 and 2009, 21 patients diagnosed with primary spontaneous CSF rhinorrhea underwent surgery in the authors' hospital. The clinical aspects were retrospectively reviewed, and their characteristics were analyzed.

Results

There were 18 women and 3 men, whose ages ranged from 37 to 74 years (mean 53 years). Body mass index (BMI) ranged from 22 to 58.8 kg/m2 (mean 31.2 kg/m2). Eighteen patients (85.7%) were overweight, and 18 (85.7%) suffered from headache or tinnitus before rhinorrhea. Radiological images revealed fully or partially empty sellae in 14 patients (66.7%). The preoperative intracranial pressure (ICP) ranged from 11 to 28 cm H2O (mean 17.6 cm H2O), while the postoperative ICP ranged from 21 to 32 cm H2O (mean 25.5 cm H2O, p < 0.01). An endoscopeassisted transnasal approach was chosen for the repair. Postoperatively, in 95.2% of patients a cure was achieved. Rhinorrhea recurred in only 1 patient, and a leakage from a new defect occurred in another patient 4 years after the operation. Both patients underwent additional surgery, which was successful. The follow-up period varied from 5 to 75 months with a mean of 34 months.

Conclusions

All patients had direct or indirect evidence of elevated ICP, most patients presented with symptoms of idiopathic intracranial hypertension (IIH), and most patients were women and obese. Primary spontaneous CSF rhinorrhea may be due to IIH, and it is a rare symptom of IIH. When treating or monitoring these patients during follow-up, ICP should be controlled, and other symptoms of IIH should be noted.