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Zulma Tovar-Spinoza and Hoon Choi

OBJECTIVE

Magnetic resonance–guided laser interstitial thermal therapy (MRgLITT) is a novel, minimally invasive treatment that has multiple advantages in pediatric use and broad applicability for different types of lesions. Here, the authors report the preliminary results of the first series of pediatric brain tumors treated with MRgLITT at Golisano Children's Hospital in Syracuse, New York.

METHODS

Pediatric brain tumors treated with MRgLITT between February 2012 and August 2014 at Golisano Children's Hospital were evaluated retrospectively. Medical records, radiological findings, surgical data, complications, and results of tumor volumetric analyses were reviewed. The Visualase thermal laser system (Medtronic) was used in all MRgLITT procedures.

RESULTS

This series included 11 patients with 12 tumors (pilocytic astrocytoma, ependymoma, medulloblastoma, choroid plexus xanthogranuloma, subependymal giant cell astrocytoma, and ganglioglioma). A single laser and multiple overlapping ablations were used for all procedures. The mean laser dose was 10.23 W, and the mean total ablation time was 68.95 seconds. The mean initial target volume was 6.79 cm3, and the mean immediate post-ablation volume was 7.86 cm3. The mean hospital stay was 3.25 days, and the mean follow-up time was 24.5 months. Tumor volume decreased in the first 3 months after surgery (n = 11; p = 0.007) and continued to decrease by the 4- to 6-month followup (n = 11; mean volume 2.61 cm3; p = 0.009). Two patients experienced post-ablation complications: transient right leg weakness in one patient, and transient hemiparesis, akinetic mutism, and eye movement disorder in the other.

CONCLUSIONS

Magnetic resonance–guided laser interstitial thermal therapy is an effective first- or second-line treatment for select pediatric brain tumors. Larger multiinstitutional clinical trials are necessary to evaluate its use for different types of lesions to further standardize practices.

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Byung-Wan Choi, Dong-Hoon Baek, Lindsey C. Sheffler and Han Chang

OBJECT

The progression of cervical ossification of the posterior longitudinal ligament (OPLL) can lead to increase in the size of the OPLL mass and aggravation of neurological symptoms. In the present study, the authors aimed to analyze the progression of cervical OPLL by using CT imaging, elucidate the morphology of OPLL masses, and evaluate the factors associated with the progression of cervical OPLL.

METHODS

Sixty patients with cervical OPLL were included. All underwent an initial CT examination and had at least 24 months’ follow-up with CT. The mean duration of follow-up was 29.6 months. Fourteen patients (Group A) had CT evidence of OPLL progression, and 46 (Group B) did not show evidence of progression on CT. The 2 groups were compared with respect to the following variables: sex, age, number of involved segments, type of OPLL, and treatment methods. The CT findings, such as the connection of an OPLL mass with the vertebral body and formation of trabeculation in the mass, were evaluated.

RESULTS

Sex and treatment modality were not associated with OPLL progression. The mean age of the patients in Group A was significantly lower than that in Group B (p = 0.03). The mean number of involved segments was 5.3 in Group A and 3.6 in Group B (p = 0.002). Group A had a higher proportion of cases with the mixed type of OPLL, whereas Group B had a higher proportion of cases with the segmental type (p = 0.02). A connection between the vertebral body and OPLL mass and trabeculation formation were more common in Group B (p < 0.01).

CONCLUSIONS

Progression of cervical OPLL is associated with younger age, involvement of multiple levels, and mixed-type morphology. OPLL masses that are contiguous with the vertebral body and have trabecular formation are useful findings for identifying masses that are less likely to progress.

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Amit Singla, Eric M. Deshaies, Vlad Melnyk, Gentian Toshkezi, Amar Swarnkar, Hoon Choi and Lawrence S. Chin

The role of preoperative embolization in meningioma management remains controversial, even though 4 decades have passed since it was first described. It has been shown to offer benefits such as decreased blood loss and “softening of the tumor” during subsequent resection. However, the actual benefits remain unclear, and the potential harm of an additional procedure along with the cost of embolization have limited its use to a small proportion of the meningiomas treated.

In this article the authors retrospectively reviewed their experience with preoperative embolization of meningiomas over the previous 6 years (March 2007–March 2013). In addition, they performed a MEDLINE search using a combination of the terms “meningioma,” “preoperative,” and “embolization” to analyze the indications, embolizing agents, timing, and complications reported during preoperative embolization of meningiomas. In this retrospective review, 18 cases (female/male ratio 12:6) were identified in which endovascular embolization was used prior to resection of an intracranial meningioma. Craniotomy for tumor resection was performed within 4 days after endovascular embolization in all cases, with an average time to surgery of 1.9 days. The average duration of surgery was 4 hours and 18 minutes, and the average blood loss was 574 ml, with a range of 300–1000 ml. Complications following endovascular therapy were identified in 3 (16.7%) of 18 cases, including one each of transient hemiparesis, permanent hemiparesis, and tumor swelling.

The literature review returned 15 articles consisting of a study population greater than 25 patients. No randomized controlled study was found. The use of small polyvinyl alcohol particles (45–150 μm) is more effective in preoperative devascularization than larger particles (150–250 μm), but is criticized due to the higher risk of complications such as cranial nerve palsies and postprocedural hemorrhage. Time to surgery after embolization is inconsistently reported across the articles, and conclusions on the appropriate timing of surgery could not be drawn. The overall complication rate reported after treatment with preoperative meningioma embolization ranges from as high as 21% in some of the older literature to approximately 6% in recent literature describing treatment with newer embolization techniques. The evidence in the literature supporting the use of preoperative meningioma embolization is mainly from case series, and represents Level III evidence. Due to the lack of randomized controlled clinical trials, it is difficult to draw any significant conclusions on the overall usefulness of preoperative embolization during the management of meningiomas to consider it a standard practice.

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Hyunho Choi, Ji Yeoun Lee, Ji Hoon Phi, Seung-Ki Kim, Byung-Kyu Cho and Kyu-Chang Wang

Object

Postoperative epidural hematoma (EDH), a blood collection between the inserted galeal flap and the overlying skull flap (epigaleal flap hematoma), is a frustrating complication of the surgical treatment of moyamoya disease (MMD) in pediatric patients. The symptoms of postoperative EDH are often similar to those of postoperative cerebral ischemia, and may cause confusion during clinical decision making. The authors designed this study to evaluate the incidence, clinical presentation, risk factors, and treatment outcomes of postoperative EDH in pediatric patients with MMD.

Methods

A retrospective review of 148 pediatric patients with 250 craniotomies who underwent indirect bypass revascularization surgery between January 2002 and December 2006 was performed. This group consisted of 60 male and 88 female patients, and the mean age at surgery was 7.5 years (range 1–18 years).

Results

Of the 250 craniotomies, postoperative EDH was detected in 32 cases. In 12 cases of EDH, surgical treatment was necessary (4.8% of 250 craniotomies). During the same period, 743 non-MMD craniotomy operations were performed. In 6 of these 743 operations, patients developed postoperative EDH that required surgical treatment, significantly less than the percentage of EDH requiring postoperative treatment in patients with MMD (0.8%, p < 0.001). The average interval between craniotomy surgery and the detection of EDH was 1.8 days (range 0–5 days) in patients with MMD and 0.5 days (range 0–2 days; p = 0.018) in the non-MMD craniotomy group.

Postoperative EDH was observed in significantly fewer cases (17 of 191) when a subcutaneous drain (SCD) was inserted over the bone flap than in cases in which an SCD was not inserted (14 of 55; p = 0.001). The mean international normalized ratio of prothrombin time in the immediate postoperative blood test was 1.27 ± 0.17 in the EDH group and 1.20 ± 0.11 in the non-EDH group (values are expressed as the mean ± SD; p = 0.008). Central galeal flap tenting suture and immediate postoperative platelet count were not related to the incidence of postoperative EDH following pediatric MMD surgery.

Conclusions

Postoperative EDH is more likely to be found following craniotomy in patients with MMD than in those without MMD, and may occur in a delayed fashion. Insertion of an SCD and immediate correction of an abnormal value for international normalized ratio of prothrombin time can decrease the incidence of postoperative EDH following surgery for pediatric MMD.

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Kyu-Won Shim, Sun-Young Joo, Se-Hoon Kim, Joong-Uhn Choi and Dong-Seok Kim

Object

Medulloblastoma is the most common malignant neuroepithelial tumor found in children. Several reports have described efforts to identify the prognostic significance of various patterns of pathological and immunohistochemical features in medulloblastoma, but the published data appear to be controversial. The authors therefore attempted to demonstrate these prognostic factors convincingly in a retrospective study performed in patients with medulloblastoma.

Methods

The data used were obtained in 58 patients with medulloblastoma who were > 3 years of age and in whom > 1 year of follow-up was available after the maximal resection, craniospinal irradiation, and chemotherapy treatments. These assessments were performed to compare the immunohistochemical features to cellular differentiation, the proliferation index (PI), the apoptotic index (AI), and oncogenesis revealed by TrkC and c-erbB-3. In addition, the authors tried to determine the prognostic utility of these results in this tumor category.

Results

There was no statistically significant correlation between the prognosis and the degree of cell differentiation, but a positive correlation was noted between the PI and the AI in a tumor mass. The number of cases with a PI > 10% was significantly greater in the group of tumors in patients with recurrent medulloblastoma. A close association between the PI as a continuous variable and the progression-free and overall survival was also found. Most importantly, the PI is the only significant prognostic factor for the overall survival of patients with medulloblastoma.

Conclusions

Therefore, the authors suggest that the PI is directly linked to the prognostic factor for medulloblastoma and that immunohistochemical staining is a potentially powerful tool for predicting the prognosis of patients with medulloblastoma.

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Jae-Hoon Lee, Hwa-Seok Chang, Eun-Hee Kang, Dai-Jung Chung, Chi-Bong Choi, Jong-Hwan Lee, Soo-Han Hwang, Hoon Han and Hwi-Yool Kim

Object

The authors describe a method for percutaneous transplantation of human umbilical cord blood (hUCB)–derived multipotent stem cells (MSCs) under fluoroscopic guidance. The investigators then tested whether percutaneous transplantation of hUCB-derived MSCs improved neurological functional recovery after acute spinal cord injury (SCI).

Methods

The authors induced SCI in 10 dogs by percutaneous balloon compression. The 10 injured dogs were assigned randomly to the following groups (2 dogs each): Group 1, evaluated 2 weeks after sham transplantation; Group 2, evaluated 2 weeks after transplantation; Group 3, evaluated 4 weeks after sham transplantation; Group 4, evaluated 4 weeks after transplantation; and Group 5, evaluated 4 weeks after multispot transplantations. The dogs with sham transplantation (Groups 1 and 3) received the same volume of saline, as a control. A spinal needle was advanced into the spinal canal, and the investigators confirmed that the end of the spinal needle was located in the ventral part of spinal cord parenchyma by using contrast medium under fluoroscopic guidance. The hUCB-derived MSCs were transplanted into the cranial end of the injured segment in 6 injured dogs at 7 days after SCI.

Results

Two dogs in Group 2 showed no improvement until 2 weeks after transplantation. Three of 4 dogs (Groups 4 and 5) that received cellular transplants exhibited gradual improvement in hindlimb locomotion from 3 weeks after cell transplantation. The CM-DiI–labeled hUCB-derived MSCs were observed in the spinal cord lesions at 4 weeks posttransplantation and exerted a significant beneficial effect by reducing cyst and injury size. The transplanted cells were positive for NeuN, glial fibrillary acidic protein, and von Willebrand factor.

Conclusions

The percutaneous transplantation technique described here can be easily performed, and it differs from previous techniques by avoiding surgical exposure and allowing cells to be more precisely transplanted into the spinal cord. This technique has many potential applications in the treatment of human SCI by cell transplantation. The results also suggest that transplantation of hUCB-derived MSCs may have therapeutic effects that decrease cavitation for acute SCI.

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Jung Won Choi, Sung Min Son, Inhee Mook-Jung, Youn Joo Moon, Ji Yeoun Lee, Kyu-Chang Wang, Hyun-Seung Kang, Ji Hoon Phi, Seung Ah Choi, Sangjoon Chong, Jayoung Byun and Seung-Ki Kim

OBJECTIVE

Moyamoya disease (MMD) is a unique cerebrovascular disorder characterized by the progressive occlusion of the bilateral internal carotid arteries. Endothelial colony-forming cells (ECFCs), previously termed “endothelial progenitor cells,” play an important role in the pathogenesis of MMD. In this study, the authors performed morphological and functional studies of the mitochondria of ECFCs from patients with MMD to present new insights into the pathogenesis of the disease.

METHODS

The morphology of ECFCs from 5 MMD patients and 5 healthy controls was examined under both a transmission electron microscope and a confocal laser scanning microscope. The oxygen consumption rates (OCRs), mitochondrial membrane potentials (MMPs), intracellular Ca2+ concentrations, mitochondrial enzyme activities, and reactive oxygen species (ROS) levels were measured. Functional activity of the ECFCs was evaluated using a capillary tube formation assay.

RESULTS

The ECFCs from the MMD patients displayed a disrupted mitochondrial morphology, including a shorter and more circular shape. The ECFC mitochondria from the MMD patients exhibited functional abnormalities, which were assessed as a decreased OCR and an increased intracellular Ca2+ concentration. Moreover, the ECFCs from MMD patients showed increased ROS levels. Interestingly, treatment with an ROS scavenger not only reversed the mitochondrial abnormalities but also restored the angiogenic activity of the ECFCs from the MMD patients.

CONCLUSIONS

The mitochondria of ECFCs from MMD patients, as compared with those from healthy patients, exhibited morphological and functional abnormalities. This finding suggests that the mitochondrial abnormalities may have a role in the pathogenesis of MMD.

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Hyeoncheol Hwang, Kyu-Chang Wang, Moon Suk Bang, Hyung-Ik Shin, Seung-Ki Kim, Ji Hoon Phi, Ji Yeoun Lee, Jinwoo Choi, Seungwoo Cha and Keewon Kim

OBJECTIVE

The aim of this study was to establish optimal electric stimulation parameters for intraoperatively monitoring the bulbocavernosus reflexes (BCRs) in infants.

METHODS

The authors retrospectively reviewed the medical records of all infants (age < 24 months) who had undergone an untethering operation for tethered cord syndrome between May 2013 and February 2014 at a single institution and whose baseline BCR had been elicited during surgery. Using different combinations of stimulation parameters—number of stimulation pulses: 4 or 8 pulses, interpulse interval: 1, 2, or 5 msec, and polarity of stimulation: biphasic or monophasic—the authors compared the relative mean amplitude of 10 BCR responses (rmaBCRs) to each combination of parameters.

RESULTS

The rmaBCRs were larger with the 8-pulse stimulations than with the 4-pulse stimulations (p < 0.0001). There was a tendency, though not statistically significant, for larger rmaBCRs to be obtained with the longer interpulse interval in the 8-pulse stimulation (p = 0.1289). The biphasic stimulation produced larger rmaBCRs than the monophasic stimulation (p = 0.0005).

CONCLUSIONS

Biphasic 8-pulse stimulations with 5-msec or 2-msec intervals yield the largest BCR responses. Considering that an 8-pulse stimulation with 5-msec intervals may overlap the onset of the BCR, a biphasic 8-pulse stimulation with 2-msec intervals is recommended as the optimal stimulation paradigm to monitor intraoperative BCRs in infants.

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Young-Hoon Kim, Young Jin Lee, Jung Ho Han, Soyeon Ahn, Jaebong Lee, Jae Hyoung Kim, Byung Se Choi, Jae Seung Bang, Chae-Yong Kim, Gyojun Hwang, O-Ki Kwon and Chang Wan Oh

OBJECT

The authors aimed to assess whether the prevalence of intracranial aneurysms in patients with intracranial meningiomas was higher than that in a healthy population.

METHODS

The authors performed a hospital-based case-control study of 300 patients with newly diagnosed intracranial meningiomas and 900 age- and sex-matched controls without a history of brain tumors to evaluate any associations between intracranial aneurysms and intracranial meningiomas. Unconditional multivariate logistic regression models were used for case-control comparisons.

RESULTS

Intracranial aneurysms were identified in 23 patients (7.7%) and 24 controls (2.7%; p < 0.001). There was a significant association between intracranial aneurysms and intracranial meningiomas (OR 2.913, 95% CI 1.613–5.261) and hypertension (OR 1.905, 95% CI 1.053–3.446). In a subgroup analysis of the patients with newly diagnosed intracranial meningiomas, there was a significant association between intracranial aneurysms and hypertension (OR 2.876, 95% CI 1.125–7.352) and tumor volume (OR 1.012, 95% CI 1.001–1.024). These patients were also more likely than controls to have other intracranial vascular diseases (p < 0.001), such as isolated occlusion of the intracranial vessels, excluding intracranial aneurysms.

CONCLUSIONS

The prevalence of intracranial aneurysms was higher in patients with intracranial meningiomas. Hypertension and tumor volume appear to be associated with the formation of intracranial aneurysms in these patients.

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Ji Yeoun Lee, Sangjoon Chong, Young Hun Choi, Ji Hoon Phi, Jung-Eun Cheon, Seung-Ki Kim, Sung Hye Park, In-One Kim and Kyu-Chang Wang

OBJECTIVE

Since the entity limited dorsal myeloschisis (LDM) was proposed, numerous confusing clinical cases have been renamed according to the embryopathogenesis. However, clinical application of this label appears to require some clarification with regard to pathology. There have been cases in which all criteria for the diagnosis of LDM were met except for the presence of a neural component in the stalk, an entity the authors call “probable” LDM. The present study was performed to meticulously review these cases and suggest that a modified surgical strategy using limited laminectomy is sufficient to achieve the surgical goal of untethering.

METHODS

The authors retrospectively reviewed the imaging findings, operative notes, and pathology reports of spinal dysraphism patients with subcutaneous stalk lesions who had presented to their institution between 2010 and 2014.

RESULTS

Among 33 patients with LDM, 13 had the typical nonsaccular lesions with simple subcutaneous stalks connecting the skin opening to the spinal cord. Four cases had “true” LDM meeting all criteria for diagnosis, including pathological confirmation of CNS tissue by immunohistochemical staining with glial fibrillary acidic protein. There were also 9 cases in which all clinical, imaging, and surgical findings were compatible with LDM, but the “neural” component in the resected stalk was not confirmed. For all the cases, limited exposure of the stalk was done and satisfactory untethering was achieved.

CONCLUSIONS

One can speculate based on the initial error of embryogenesis that if the entire stalk were traced to the point of insertion on the cord, the neural component would be proven. However, this would require an extended level of laminectomy/laminotomy, which may be unnecessary, at least with regard to the completeness of untethering. Therefore, the authors propose that for some selected cases of LDM, a minimal extent of laminectomy may suffice for untethering, although it may be insufficient for diagnosing a true LDM.