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Peng Xu, Wei-Ming Gong, Yao Li, Tao Zhang, Kai Zhang, De-Zhen Yin and Tang-Hong Jia

Object

Chronic mechanical compression of the spinal cord, which is commonly caused by degeneration of the spine, impairs motor and sensory functions insidiously and progressively. Yet the exact mechanisms of chronic spinal cord compression (SCC) remain to be elucidated. To study the pathophysiology of this condition, the authors developed a simple animal experimental model that reproduced the clinical course of mechanical compression of the spinal cord.

Methods

A custom-designed compression device was implanted on the exposed spinal cord of female Wistar rats between the T-7 and T-9 vertebrae. A root canal screw attached to a plastic plate was tightened 1 complete turn (1 pitch) every 7 days for 6 weeks. The placement of the compression device and the degree of compression were validated every week using radiography. Furthermore, a motor sensory deficit index was also calculated every week. After 3, 6, 9, or 12 weeks, the compressed T7–9 spinal cords were harvested and examined histologically.

Results

Lateral projection of the thoracic spine showed a progressively increasing rate of mean spinal cord narrowing in the compression group. Motor and sensory deficiencies were observed from Week 3 onward; paralysis was observed in 2 rats at Week 12. Motor deficiency appeared earlier than sensory deficiency. Obvious pathological changes were observed starting at Week 6. The number of neurons in the gray matter of rats with chronic compression of the spinal cord decreased progressively in the 6- and 9-week compression groups. In the white matter, myelin destruction and loss of axons and glia were noted. The number of terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling (TUNEL)–positive neurons increased in the ventral-to-dorsal direction. The number of TUNEL-positive cells increased from Week 6 onward and peaked at Week 9.

Conclusions

This practical model accurately reproduces characteristic features of clinical chronic SCC, including progressive motor and sensory disturbances after a latency and insidious neuronal loss.

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Kai-Bing Tian, Jing-Jie Zheng, Jun-Peng Ma, Shu-Yu Hao, Liang Wang, Li-Wei Zhang, Zhen Wu, Jun-Ting Zhang and Da Li

OBJECTIVE

The natural history of cerebral cavernous malformations (CMs) has been widely studied, but the clinical course of untreated thalamic CMs is largely unknown. Hemorrhage of these lesions can be devastating. The authors undertook this study to obtain a prospective hemorrhage rate and provide a better understanding of the prognosis of untreated thalamic CMs.

METHODS

This longitudinal cohort study included patients with thalamic CMs who were diagnosed between 2000 and 2015. Clinical data were recorded, radiological studies were extensively reviewed, and follow-up evaluations were performed.

RESULTS

A total of 121 patients were included in the study (56.2% female), with a mean follow-up duration of 3.6 years. The overall annual hemorrhage rate (subsequent to the initial presentation) was calculated to be 9.7% based on the occurrence of 42 hemorrhages over 433.1 patient-years. This rate was highest in patients (n = 87) who initially presented with hemorrhage and focal neurological deficits (FNDs) (14.1%) (χ2 = 15.358, p < 0.001), followed by patients (n = 19) with hemorrhage but without FND (4.5%) and patients (n = 15) without hemorrhage regardless of symptoms (1.2%). The initial patient presentations of hemorrhage with FND (hazard ratio [HR] 2.767, 95% CI 1.336–5.731, p = 0.006) and associated developmental venous anomaly (DVA) (HR 2.510, 95% CI 1.275–4.942, p = 0.008) were identified as independent hemorrhage risk factors. The annual hemorrhage rate was significantly higher in patients with hemorrhagic pres entation at diagnosis (11.7%, p = 0.004) or DVA (15.7%, p = 0.002). Compared with the modified Rankin Scale (mRS) score at diagnosis (mean 2.2), the final mRS score (mean 2.0) was improved in 37 patients (30.6%), stable in 59 patients (48.8%), and worse in 25 patients (20.7%). Lesion size (odds ratio [OR] per 0.1 cm increase 3.410, 95% CI 1.272–9.146, p = 0.015) and mRS score at diagnosis (OR per 1 point increase 3.548, 95% CI 1.815–6.937, p < 0.001) were independent adverse risk factors for poor neurological outcome (mRS score ≥ 2). Patients experiencing hemorrhage after the initial ictus (OR per 1 ictus increase 6.923, 95% CI 3.023–15.855, p < 0.001) had a greater chance of worsened neurological status.

CONCLUSIONS

This study verified the adverse predictors for hemorrhage and functional outcomes of thalamic CMs and demonstrated an overall annual symptomatic hemorrhage rate of 9.7% after the initial presentation. These findings and the mode of initial presentation are useful for clinicians and patients when selecting an appropriate treatment, although the tertiary referral bias of the series should be taken into account.

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Feng Zhou, Zixiao Yang, Wei Zhu, Liang Chen, Jianping Song, Kai Quan, Sichen Li, Peiliang Li, Zhiguang Pan, Peixi Liu and Ying Mao

OBJECTIVE

Epidermoid cysts of the cavernous sinus (CS) are rare, and no large case series of these lesions has been reported. In this study, the authors retrospectively reviewed the outcomes of the surgical management of CS epidermoid cysts undertaken at their center and performed a review of any such cysts reported in the literature over the past 40 years.

METHODS

Clinical data were obtained on 31 patients with CS epidermoid cysts that had been surgically treated at the authors’ hospital between 2001 and 2016. The patients’ medical records, imaging data, and follow-up outcomes were retrospectively analyzed. The related literature from the past 40 years (18 articles, 20 patients) was also evaluated.

RESULTS

The most common chief complaints were facial numbness or hypesthesia (64.5%), absent corneal reflex (45.2%), and abducens or oculomotor nerve deficit (35.5%). On MRI, 51.6% of the epidermoid cysts showed low T1 signals and equal or high T2 signals. In the other lesions, the radiological findings varied considerably given differences in the composition of the cysts. Surgery was performed via the extradural approach (58.1%), intradural approach (32.3%), or a combined approach (9.7%). After the operation, symptoms remained similar or improved in 90.3% of patients and new oculomotor paralysis developed after the operation in 9.7% of patients. Seven patients (22.6%) developed meningitis postoperatively (5 aseptic and 2 septic), and all of them recovered. All patients achieved good recovery before discharge (Karnofsky Performance Status score ≥ 70). Over an average follow-up of 4.6 ± 3.0 years in 25 patients (80.6%), no recurrence or reoperation occurred, regardless of whether total or subtotal resection of the capsule had been achieved.

CONCLUSIONS

Both the extradural and intradural approaches can enable satisfactory lesion resection. A favorable prognosis and symptomatic improvement can be expected after both total and subtotal capsule resections. Total capsule resection is encouraged to minimize the possibility of recurrence provided that the resection can be safely performed.

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Xinyu Liu, Yanguo Wang, Xiaojuan Wu, Yanping Zheng, Long Jia, Junyan Li, Kai Zhang, Jianmin Li and Bin Wei

Object

In this paper, the authors assessed the effects of different surgical approaches and reconstructive methods on the spinous process after lumbar surgery in sheep.

Methods

A total of 41 healthy, adult sheep weighing 38–40 kg were used in this study. The animals were randomly divided into 4 groups (10 animals per group and 1 control). Animals in Group A underwent a spinous process–splitting procedure to expose the lamina. Animals in Group B had bilateral multifidus muscles stripped and the spinous process excised. All animals in Group C underwent unilateral stripping of the multifidus muscle from the spinous process (Group C1) as well as spinous process splitting at the bottom to expose the contralateral lamina attached to the multifidus muscle (Group C2). To mimic the laminoplasty procedure, the multifidus muscles were stripped bilaterally in Group D. For all groups, the surgical level (L-6), length of incision (4 cm), the retracting distance, and time (40 minutes) remained constant. Ten months after surgery, the atrophy rate of the cross-sectional areas (CSAs) of the multifidus muscle, MR imaging findings, and histological changes of the muscle tissue were evaluated. Normal multifidus muscles taken from a healthy sheep at the L-6 level and the preoperative data of MR imaging in experimental animals provided control data (Group E).

Results

The MR imaging and histological scores of multifidus muscles from sheep in Groups A, B, C1, C2, and D were significantly decreased, and the atrophy rates were significantly higher than those from sheep in Group E (p < 0.05). The postoperative MR imaging and histological scores obtained in Groups A and C2 were highest and the atrophy rates were lowest, while animals from Group B had the highest atrophy rate and lowest MR imaging and histological scores among all experimental groups (p < 0.05). The scores for animals in Groups A and C2, in which the muscles were not stripped from the spinous process, achieved lower atrophy rates and higher MR imaging and histological scores than those for sheep in Groups C1 and D, in which the muscles were stripped (p < 0.05). The groups in which the spinous process was reconstructed after detachment of the muscles (Groups C1 and D) had lower atrophy rates and higher MR imaging and histological scores than Group B (p < 0.05).

Conclusions

The multifidus muscle can be effectively protected by reducing the extent of muscle detachment and reconstructing the posterior bone-ligament complex. A spinous process–splitting procedure is a useful method to reduce postoperative muscle atrophy.

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Shin-Joe Yeh, Sung-Chun Tang, Li-Kai Tsai, Chung-Wei Lee, Ya-Fang Chen, Hon-Man Liu, Shih-Hung Yang, Yu-Lin Hsieh, Meng-Fai Kuo and Jiann-Shing Jeng

OBJECTIVE

Pediatric and adult patients with moyamoya disease experience similar clinical benefits from indirect revascularization surgeries, but there are still debates about age-related angiographic differences of the collaterals established after surgery. The goal of this study was to assess age-related differences on ultrasonography before and after indirect revascularization surgeries in moyamoya patients, focusing on some ultrasonographic parameters known to be correlated with the collaterals supplied by the external carotid artery (ECA).

METHODS

The authors prospectively included moyamoya patients (50 and 26 hemispheres in pediatric and adult patients, respectively) who would undergo indirect revascularization surgery. Before surgery and at 1, 3, and 6 months after surgery, the patients underwent ultrasonographic examinations. The ultrasonographic parameters included peak-systolic velocity (PSV), end-diastolic velocity (EDV), resistance index (RI), and flow volume (FV) measured in the ECA, superficial temporal artery (STA), and internal carotid artery on the operated side. The mean values, absolute changes, and percentage changes of these parameters were compared between the pediatric and adult patients. Logistic regression analysis was used to clarify the determinants affecting postoperative EDV changes in the STA.

RESULTS

Before surgery, the adult patients had mean higher EDV and lower RI in the STA and ECA than the pediatric group (all p < 0.05). After surgery, the pediatric patients had greater changes (absolute and percentage changes) in the PSV, EDV, RI, and FV in the STA and ECA (all p < 0.05). The factors affecting postoperative EDV changes in the STA at 6 months were age (p = 0.006) and size of the revascularization area (i.e., revascularization in more than the temporal region vs within the temporal region; p = 0.009). Pediatric patients who received revascularization procedures in more than the temporal region had higher velocities (PSV and EDV) in the STA than those who received revascularization within the temporal region (p < 0.05 at 1–6 months), but such differences were not observed in the adult group.

CONCLUSIONS

The greater changes of these parameters in the STA and ECA in pediatric patients than in adults after indirect revascularization surgeries indicated that pediatric patients might have a greater increase of collaterals postoperatively than adults. Pediatric patients who undergo revascularization in more than the temporal region might have more collaterals than those who undergo revascularization within the temporal region.

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Peigen Xie, Feng Feng, Junyan Cao, Zihao Chen, Bingjun He, Zhuang Kang, Lei He, Wenbin Wu, Lei Tan, Kai Li, Rongqin Zheng and Limin Rong

OBJECTIVE

Percutaneous transforaminal endoscopic discectomy (PTED) is usually performed under fluoroscopic guidance and is associated with a large radiation dose. Ultrasonography (US)–MR image fusion navigation combines the advantages of US and MRI and requires significantly less radiation than fluoroscopy. The purpose of this study was to evaluate the safety and effectiveness of US-MR image fusion navigation for PTED.

METHODS

From January to September 2018, patients with L4–5 lumbar disc herniation requiring PTED were randomized to have the procedure conducted with US-MR image fusion navigation or fluoroscopy. The number of fluoroscopies, radiation dose, duration of imaging guidance, intraoperative visual analog scale (VAS) pain score, intraoperative complications, and clinical outcomes were compared between the groups.

RESULTS

There were 10 patients in the US-MR navigation group and 10 in the fluoroscopy group, and there were no significant differences in age, sex ratio, or BMI between the 2 groups (all p > 0.05). Intraoperatively, the total radiation dose, number of fluoroscopies performed, duration of image guidance, and VAS low-back and leg pain scores were all significantly lower in the US-MRI navigation group than in the fluoroscopy group (all p < 0.05). There were no intraoperative complications in either group. Postoperative improvements in Japanese Orthopaedic Association, Oswestry Disability Index, and VAS pain scale scores were similar between the 2 groups.

CONCLUSIONS

US-MR image fusion navigation is a promising technology for performing PTED and requires significantly less radiation than fluoroscopy.

Clinical trial registration no.: NCT03403244 (ClinicalTrials.gov).

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Xiao-hui Ren, Chun Chu, Chun Zeng, Yong-ji Tian, Zhen-yu Ma, Kai Tang, Lan-bing Yu, Xiang-li Cui, Zhong-cheng Wang and Song Lin

Object

Intracranial epidermoid cysts are rare, potentially curable, benign lesions that are sometimes associated with severe postoperative complications, including hemorrhage. Delayed hemorrhage, defined as one that occurred after an initial unremarkable postoperative CT scan, contributed to most cases of postoperative hemorrhage in patients with epidermoid cyst. In this study, the authors focus on delayed hemorrhage as one of the severe postoperative complications in epidermoid cyst, report its incidence and its clinical features, and analyze related clinical parameters.

Methods

There were 428 cases of intracranial epidermoid cysts that were surgically treated between 2002 and 2008 in Beijing Tiantan Hospital, and these were retrospectively reviewed. Among them, the cases with delayed postoperative hemorrhage were chosen for analysis. Clinical parameters were recorded, including the patient's age and sex, the chief surgeon's experience in neurosurgery, the year in which the operation was performed, tumor size, adhesion to neurovascular structures, and degree of resection. These parameters were compared in patients with and without delayed postoperative hemorrhage to identify risk factors associated with this entity.

Results

The incidences of postoperative hemorrhage and delayed postoperative hemorrhage in patients with epidermoid cyst were 5.61% (24 of 428) and 4.91% (21 of 428), respectively, both of which were significantly higher than that of postoperative hemorrhage in all concurrently treated intracranial tumors, which was 0.91% (122 of 13,479). The onset of delayed postoperative hemorrhage ranged from the 5th to 23rd day after the operation; the median time of onset was the 8th day. The onset manifestation included signs of intracranial hypertension and/or meningeal irritation (71.4%), brain herniation (14.3%), seizures (9.5%), and syncope (4.8%). Neuroimages revealed hematoma in 11 cases and subarachnoid hemorrhage in 10 cases. The rehemorrhage rate was 38.1% (8 of 21). The mortality rate for delayed postoperative hemorrhage was 28.6% (6 of 21). None of the clinical parameters was correlated with delayed postoperative hemorrhage (p > 0.05), despite a relatively lower p value for adhesion to neurovascular structures (p = 0.096).

Conclusions

Delayed postoperative hemorrhage contributed to most of the postoperative hemorrhages in patients with intracranial epidermoid cysts and was a unique postoperative complication with unfavorable outcomes. Adhesion to neurovascular structures was possibly related to delayed postoperative hemorrhage (p = 0.096).

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Tao Zhang, Zhenhua Li, Weiming Gong, Bingwei Sun, Shuheng Liu, Kai Zhang, Dezhen Yin, Peng Xu and Tanghong Jia

Object.

The authors assessed the efficacy of computed tomography (CT)–guided percutaneous injection of fibrin glue to treat meningeal cysts of the sacral spine in patients with back pain, and evaluated the necessity for cerebrospinal fluid (CSF) aspiration before glue injection.

Methods.

Of the 31 patients in this study, 15 underwent injection of fibrin glue under CT guidance after aspiration of more than 15 ml of CSF (Group A), and 16 patients were treated with the glue but without CSF aspiration (Group B). Clinical results were evaluated after an average of 23 months of follow-up, and changes on the imaging studies were also evaluated. The clinical outcome and postoperative complications were analyzed.

Results.

All 31 patients experienced resolution or marked improvement of symptoms for as long as 28 months after fibrin glue therapy. No patient experienced recurrence of symptoms during the follow-up interval. The postoperative pain relief was statistically significant (p < 0.001) according to evaluations in which a 100-mm visual analog pain scale was used. There were no statistical differences between the two groups (p > 0.05).

Conclusions.

Percutaneous CT-guided fibrin glue therapy for sacral arachnoid cysts may be a definitive therapy. It is unnecessary to aspirate the CSF before injection of the fibrin glue.

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Feng Wan, Ling Li, Jingcao Chen, Jian Chen, Ting Lei, Delin Xue, Hongquan Niu, Kai Shu, Ping Zhang, Zhengming Yang and Yuping Wang

Object

The authors performed a study to investigate the clinical manifestations, treatment strategies, and possible pathogenesis of conus medullaris schistosomiasis.

Methods

Six cases collected from the authors’ experience and four cases reported in the literature were studied retrospectively for clinical manifestations, treatment outcomes, and prognosis. All patients experienced progressive lower-extremity weakness and functional bowel and bladder impairment. Although the magnetic resonance (MR) imaging results suggested the presence of a conus medullaris tumor, schistosomiasis was diagnosed based on pathological results obtained in the 10 patients. The results of surgery followed by pyquiton and hormone treatment confirmed the diagnosis, and the patients’ prognoses were good.

Conclusions

This pathological entity is predominantly found in adults, and the clinical manifestations have no specificity, although the MR imaging may provide some clues. As a form of ectopic schistosomiasis, conus medullaris schistosomiasis deserves special consideration and further exploration. If an early diagnosis can be made and pyquiton and hormone therapy is given, surgery can be avoided and the prognosis will remain good.

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Abel Po-Hao Huang, Jui-Chang Tsai, Lu-Ting Kuo, Chung-Wei Lee, Hong-Shiee Lai, Li-Kai Tsai, Sheng-Jean Huang, Chien-Min Chen, Yuan-Shen Chen, Hao-Yu Chuang and Max Wintermark

Object

Currently, perfusion CT (PCT) is a valuable imaging technique that has been successfully applied to the clinical management of patients with ischemic stroke and aneurysmal subarachnoid hemorrhage (SAH). However, recent literature and the authors' experience have shown that PCT has many more important clinical applications in a variety of neurosurgical conditions. Therefore, the authors share their experiences of its application in various diseases of the cerebrovascular, neurotraumatology, and neurooncology fields and review the pertinent literature regarding expanding PCT applications for neurosurgical conditions, including pitfalls and future developments.

Methods

A pertinent literature search was conducted of English-language articles describing original research, case series, and case reports from 1990 to 2011 involving PCT and with relevance and applicability to neurosurgical disorders.

Results

In the cerebrovascular field, PCT is already in use as a diagnostic tool for patients suspected of having an ischemic stroke. Perfusion CT can be used to identify and define the extent of the infarct core and ischemic penumbra core, and thus aid patient selection for acute reperfusion therapy. For patients with aneurysmal SAH, PCT provides assessment of early brain injury, cerebral ischemia, and infarction, in addition to vasospasm. It may also be used to aid case selection for aggressive treatment of patients with poor SAH grade. In terms of oncological applications, PCT can be used as an imaging biomarker to assess angiogenesis and response to antiangiogenetic treatments, differentiate between glioma grades, and distinguish recurrent tumor from radiation necrosis. In the setting of traumatic brain injury, PCT can detect and delineate contusions at an early stage. In patients with mild head injury, PCT results have been shown to correlate with the severity and duration of postconcussion syndrome. In patients with moderate or severe head injury, PCT results have been shown to correlate with patients' functional outcome.

Conclusions

Perfusion CT provides quantitative and qualitative data that can add diagnostic and prognostic value in a number of neurosurgical disorders, and also help with clinical decision making. With emerging new technical developments in PCT, such as characterization of blood-brain barrier permeability and whole-brain PCT, this technique is expected to provide more and more insight into the pathophysiology of many neurosurgical conditions.