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Jae Hwan Cho, Chang Ju Hwang, Young Hyun Choi, Dong-Ho Lee and Choon Sung Lee

OBJECTIVE

Cervical sagittal alignment (CSA) is related to function and quality of life, but it has not been frequently studied in patients with adolescent idiopathic scoliosis. This study aimed to reveal the change in CSA following corrective surgery, compare the cervical sagittal parameters according to curve types, and assess related factors for postoperative aggravation of CSA.

METHODS

The authors studied 318 consecutive patients with adolescent idiopathic scoliosis who underwent corrective surgery at a single center. Occiput–C2 and C2–7 lordosis, C2–7 sagittal vertical axis (SVA), T-1 slope, thoracic kyphosis, and lumbar sagittal profiles were measured preoperatively and postoperatively. Scoliosis Research Society Outcomes Questionnaire (SRS-22) scores were used as clinical outcomes. Each radiological parameter was compared preoperatively and postoperatively according to curve types (double major, single thoracic, and double thoracic curves). Patients were grouped based on preoperative CSA: the lordotic group (group L) and the kyphotic group (group K). Each radiological parameter was compared between the groups. Related factors for postoperative aggravation of CSA were assessed using multivariate logistic analysis.

RESULTS

Of the total number of patients studied, 67.0% (213 of 318) and 54.4% (173 of 318) showed cervical kyphotic alignment preoperatively and postoperatively, respectively. C2–7 lordosis increased (from −5.8° to −1.1°; p < 0.001) and C2–7 SVA decreased (from 24.2 to 20.0 mm; p < 0.001) postoperatively regardless of curve types. Although group K showed improvement in C2–7 lordosis (from −12.7° to −4.8°; p < 0.001), group L showed no difference (from 9.0° to 6.9°; p = 0.115) postoperatively. Clinical outcomes were not related to the degree of cervical kyphosis in this cohort. C2–7 lordosis (p < 0.001) and pelvic tilt (p = 0.019) were related to postoperative aggravation of CSA.

CONCLUSIONS

Regardless of the trend of improvement in CSA, many patients (54.4%) still showed cervical kyphotic alignment postoperatively. C2–7 lordosis and C2–7 SVA improved postoperatively in all curve types. However, postoperative changes in C2–7 lordosis showed different results based on preoperative CSA, which could be related to T-1 slope and thoracic kyphosis. However, clinical outcomes showed no difference based on CSA in this study cohort. Greater C2–7 lordosis and proximal thoracic curve preoperatively were risk factors for postoperative aggravation of CSA (p < 0.001 and p = 0.019, respectively).

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Young-Seop Park, Seung-Jae Hyun, Ho Yong Choi, Ki-Jeong Kim and Tae-Ahn Jahng

OBJECTIVE

The aim of this study was to investigate the risk of upper instrumented vertebra (UIV) fractures associated with UIV screw fixation (unicortical vs bicortical) and polymethylmethacrylate (PMMA) augmentation after adult spinal deformity surgery.

METHODS

A single-center, single-surgeon consecutive series of adult patients who underwent lumbar fusion for ≥ 4 levels (that is, the lower instrumented vertebra at the sacrum or pelvis and the UIV of the thoracolumbar spine [T9–L2]) were retrospectively reviewed. Age, sex, follow-up duration, sagittal UIV angle immediately postoperatively including several balance-related parameters (lumbar lordosis [LL], pelvic incidence, and sagittal vertical axis), bone mineral density, UIV screw fixation type, UIV PMMA augmentation, and UIV fracture were evaluated. Patients were divided into 3 groups: Group U, 15 patients with unicortical screw fixation at the UIV; Group P, 16 with bicortical screw fixation and PMMA augmentation at the UIV; and Group B, 21 with bicortical screw fixation without PMMA augmentation at the UIV.

RESULTS

The mean number of levels fused was 6.5 ± 2.5, 7.5 ± 2.5, and 6.5 ± 2.5; the median age was 50 ± 29, 72 ± 6, and 59 ± 24 years; and the mean follow-up was 31.5 ± 23.5, 13 ± 6, and 24 ± 17.5 months in Groups U, P, and B, respectively (p > 0.05). There were no significant differences in balance-related parameters (LL, sagittal vertical axis, pelvic incidence–LL, and so on) among the groups. UIV fracture rates in Groups U (0%), P (31.3%), and B (42.9%) increased in sequence by group (p = 0.006). UIV bicortical screw fixation increased the risk for UIV fracture (OR 5.39; p = 0.02).

CONCLUSIONS

Bicortical screw fixation at the UIV is a major risk factor for early UIV compression fracture, regardless of whether a thoracolumbosacral orthosis is used. To reduce the proximal junctional failure, unicortical screw fixation at the UIV is essential in adult spinal deformity correction surgery.

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Eung Koo Yeon, Young Dae Cho, Dong Hyun Yoo, Su Hwan Lee, Hyun-Seung Kang, Jeong Eun Kim, Won-Sang Cho, Hyun Ho Choi and Moon Hee Han

OBJECTIVE

The authors conducted a study to ascertain the long-term durability of coiled aneurysms completely occluded at 36 months’ follow-up given the potential for delayed recanalization.

METHODS

In this retrospective review, the authors examined 299 patients with 339 aneurysms, all shown to be completely occluded at 36 months on follow-up images obtained between 2011 and 2013. Medical records and radiological data acquired during the extended monitoring period (mean 74.3 ± 22.5 months) were retrieved, and the authors analyzed the incidence of (including mean annual risk) and risk factors for delayed recanalization.

RESULTS

A total of 5 coiled aneurysms (1.5%) occluded completely at 36 months showed recanalization (0.46% per aneurysm-year) during the long-term surveillance period (1081.9 aneurysm-years), 2 surfacing within 60 months and 3 developing thereafter. Four showed minor recanalization, with only one instance of major recanalization. The latter involved the posterior communicating artery as an apparent de novo lesion, arising at the neck of a firmly coiled sac, and was unrelated to coil compaction or growth. Additional embolization was undertaken. In a multivariate analysis, a second embolization for a recurrent aneurysm (HR = 22.088, p = 0.003) independently correlated with delayed recanalization.

CONCLUSIONS

Almost all coiled aneurysms (98.5%) showing complete occlusion at 36 months postembolization proved to be stable during extended observation. However, recurrent aneurysms were predisposed to delayed recanalization. Given the low probability yet seriousness of delayed recanalization and the possibility of de novo aneurysm formation, careful monitoring may be still considered in this setting but at less frequent intervals beyond 36 months.

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Hyun Ho Choi, Young Dae Cho, Dong Hyun Yoo, Su Hwan Lee, Eung Koo Yeon, Hyun-Seung Kang, Won-Sang Cho, Jeong Eun Kim and Moon Hee Han

OBJECTIVE

In the presence of symmetric A1 flow, the safety and efficacy of compromising the anterior communicating artery (ACoA) during coil embolization of ACoA aneurysms has yet to be evaluated. Herein, the authors describe their experience, focusing on procedural safety.

METHODS

Between October 2012 and July 2017, 285 ACoA aneurysms with symmetric A1 flows were treated at the authors’ institution by endovascular coil embolization. Clinical and angiographic outcome data were subjected to binary logistic regression analysis.

RESULTS

ACoA compromise was chosen in the treatment of 71 aneurysms (24.9%), which were completely (n = 15) or incompletely (n = 56) compromised. In the remaining 214 lesions, the ACoA was preserved. Although 9 patients (3.2%) experienced procedure-related thromboembolisms (compromised, 4; preserved, 5), all but 1 patient (with ACoA compromise) were asymptomatic. In multivariate analysis, subarachnoid hemorrhage at presentation was the sole independent risk factor for thromboembolism (OR 15.98, p < 0.01), with ACoA compromise being statistically unrelated. In 276 aneurysms (96.8%) with follow-up of > 6 months (mean 20.9 ± 13.1 months, range 6–54 months), recanalization was confirmed in 21 (minor, 15; major, 6). A narrow (≤ 4 mm) saccular neck (p < 0.01) and ACoA compromise (p = 0.04) were independently linked to prevention of recanalization.

CONCLUSIONS

During coil embolization of ACoA aneurysms, the ACoA may be compromised without serious complications if A1 flows are symmetric. This approach may also confer some long-term protection from recanalization, serving as a valid treatment option for such lesions.

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Kyung Hwan Kim, So Jeong Kang, Jung-Won Choi, Doo-Sik Kong, Ho Jun Seol, Do-Hyun Nam and Jung-Il Lee

OBJECTIVE

This study aimed to verify the effect of proactive Gamma Knife surgery (GKS) in the treatment of asymptomatic meningioma compared with the natural course without any therapeutic intervention.

METHODS

From January 2006 to May 2017, 354 patients newly diagnosed with asymptomatic meningioma were reviewed and categorized into GKS (n = 153) and observation (n = 201) groups. Clinical and radiological progression rates were examined, and changes in volume were analyzed.

RESULTS

Clinical progression (i.e., clinician-judged progression), combining symptomatic progression (n = 43) and clinician-judged increase in size using images routinely acquired (n = 34), occurred in 4 patients (2.6%) and 73 patients (36.3%) in the GKS and observation groups, respectively (p < 0.001). The clinical progression-free survival (PFS) rates in the GKS and observation groups were 98.7% and 64.6%, respectively, at 5 years (p < 0.001), and 92.9% and 42.7%, respectively, at 10 years (p < 0.001). The radiological tumor control rate was 94.1% in the GKS group, and radiological progression was noted in 141 patients (70.1%) in the observation group. The radiological PFS rates in the GKS and observation groups were 94.4% and 38.5%, respectively, at 5 years (p < 0.001), and 88.5% and 7.9%, respectively, at 10 years (p < 0.001). Young age, absence of calcification, peritumoral edema, and high T2 signal intensity were correlated with clinical progression in the observation group. Volumetric analysis showed that untreated tumors gradually increased in size. However, GKS-treated tumors shrank gradually, although transient volume expansion was observed in the first 6 months. Adverse events developed in 26 of the 195 GKS-treated patients (13.3%), including 1 (0.5%) major event requiring microsurgery due to severe edema after GKS. Peritumoral edema was related to the development of adverse events (p = 0.004).

CONCLUSIONS

Asymptomatic meningioma is a benign disease; however, nearly two-thirds of patients experience tumor growth and one-third of untreated patients eventually require neurosurgical interventions during watchful waiting. GKS can control tumors clinically and radiologically with high probability. Although the risk of transient adverse events exists, proactive GKS may be a reasonable treatment option when there are no comorbidities limiting life expectancy.

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Dong Gyu Kim, Je G. Chi, Sung Hye Park, Kee Hyun Chang, Sun Ho Lee, Hee-Won Jung, Hyun Jib Kim, Byung-Kyu Cho, Kil Soo Choi and Dae Hee Han

✓ A retrospective analysis of seven patients with intraventricular neurocytoma is presented. Patient age at diagnosis ranged from 15 to 38 years (mean 24.6 years) and the male:female ratio was 6:1. Raised intracranial pressure due to hydrocephalus was the main cause of the clinical manifestations. An isodense mass with multiple intratumoral cysts and homogeneous contrast enhancement was the characteristic computerized tomography finding. The lesions commonly involved the lateral ventricle with or without extension to the third ventricle. Cerebral angiography showed homogeneous vascular staining in five patients. Magnetic resonance images revealed a mass isointense with the cerebral cortex on both T1 and T2-weighted images. Gadolinium-diethylenetriaminepenta-acetic acid-enhanced images showed homogeneous enhancement. Total removal of the tumor was possible in four patients. Pathologically, six cases were initially diagnosed as oligodendroglioma and the remaining case as ependymoma. However, immunohistochemical studies demonstrated strong positivity for neuron-specific enolase in all seven cases and for synaptophysin in five cases. On electron microscopy, three cases showed well-defined neurosecretory granules and 10-nm microtubules in their cytoplasm and cytoplasmic processes. One patient developed a recurrent tumor 18 months after surgery. The remaining six patients are free of recurrent tumors at 2 to 62 months after surgery. It is suggested that neurocytoma must be included in the differential diagnosis of intraventricular lesions, and that electron microscopic and immunohistochemical studies should be undertaken.

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Min Ho Lee, Kyung Hwan Kim, Kyung Rae Cho, Jung Won Choi, Doo-Sik Kong, Ho Jun Seol, Do-Hyun Nam and Jung-Il Lee

OBJECTIVE

Fractionated Gamma Knife surgery (FGKS) has recently been used to treat large brain metastases. However, little is known about specific volume changes of lesions during the course of treatment. The authors investigated short-term volume changes of metastatic lesions during FGKS.

METHODS

The authors analyzed 33 patients with 40 lesions who underwent FGKS for intracranial metastases of non–small-cell lung cancer (NSCLC; 25 patients with 32 lesions) and breast cancer (8 patients with 8 lesions). FGKS was performed in 3–5 fractions. Baseline MRI was performed before the first fraction. MRI was repeated after 1 or 2 fractions. Adaptive planning was executed based on new images. The median prescription dose was 8 Gy (range 6–10 Gy) with a 50% isodose line.

RESULTS

On follow-up MRI, 18 of 40 lesions (45.0%) showed decreased tumor volumes (TVs). A significant difference was observed between baseline (median 15.8 cm3) and follow-up (median 14.2 cm3) volumes (p < 0.001). A conformity index was significantly decreased when it was assumed that adaptive planning was not implemented, from baseline (mean 0.96) to follow-up (mean 0.90, p < 0.001). The average reduction rate was 1.5% per day. The median follow-up duration was 29.5 weeks (range 9–94 weeks). During the follow-up period, local recurrence occurred in 5 lesions.

CONCLUSIONS

The TV showed changes with a high dose of radiation during the course of FGKS. Volumetric change caused a significant difference in the clinical parameters. It is expected that adaptive planning would be helpful in the case of radiosensitive tumors such as NSCLCs or breast cancer to ensure an adequate dose to the target area and reduce unnecessary exposure of normal tissue to radiation.

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Kyung Hwan Kim, Doo-Sik Kong, Kyung Rae Cho, Min Ho Lee, Jung-Won Choi, Ho Jun Seol, Sung Tae Kim, Do-Hyun Nam and Jung-Il Lee

OBJECTIVE

Fractionated Gamma Knife radiosurgery (GKS) represents a feasible option for patients with large brain metastases (BM). However, the dose-fractionation scheme balanced between local control and radiation-induced toxicity remains unclear. Therefore, the authors conducted a dose-escalation study using fractionated GKS as the primary treatment for large (> 3 cm) BM.

METHODS

The exclusion criteria were more than 3 lesions, evidence of leptomeningeal disease, metastatic melanoma, poor general condition, and previously treated lesions. Patients were randomized to receive 24, 27, or 30 Gy in 3 fractions (8, 9, or 10 Gy per fraction, respectively). The primary endpoint was the development of radiation necrosis assessed by a neuroradiologist blinded to the study. The secondary endpoints included the local progression-free survival (PFS) rate, change in tumor volume, development of distant intracranial progression, and overall survival.

RESULTS

Between September 2016 and April 2018, 60 patients were eligible for the study, with 46 patients (15, 17, and 14 patients in the 8-, 9-, and 10-Gy groups, respectively) available for analysis. The median follow-up duration was 9.6 months (range 2.5–25.1 months). The 6-month estimated cumulative incidence of radiation necrosis was 0% in the 8-Gy group, 13% (95% confidence interval [CI] 0%–29%) in the 9-Gy group, and 37% (95% CI 1%–58%) in the 10-Gy group. Being in the 10-Gy group was a significant risk factor for the development of radiation necrosis (p = 0.047; hazard ratio [HR] 7.2, 95% CI 1.1–51.4). The 12-month local PFS rates were 65%, 80%, and 75% in the 8-, 9-, and 10-Gy groups, respectively. Being in the 8-Gy group was a risk factor for local treatment failure (p = 0.037; HR 2.5, 95% CI 1.1–29.6). The mean volume change from baseline was a 47.5% decrease in this cohort. Distant intracranial progression and overall survival did not differ among the 3 groups.

CONCLUSIONS

In this dose-escalation study, 27 Gy in 3 fractions appeared to be a relevant regimen of fractionated GKS for large BM because 30 Gy in 3 fractions resulted in unacceptable toxicities and 24 Gy in 3 fractions was associated with local treatment failure.

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Chiman Jeon, Chang-Ki Hong, Kyung In Woo, Sang Duk Hong, Do-Hyun Nam, Jung-Il Lee, Jung Won Choi, Ho Jun Seol and Doo-Sik Kong

OBJECTIVE

Tumors involving Meckel’s cave remain extremely challenging because of the surrounding complex neurovascular structures and deep-seated location. The authors investigated a new minimal-access technique using the endoscopic transorbital approach (eTOA) through the superior eyelid crease to Meckel’s cave and middle cranial fossa lesions and reviewed the most useful surgical procedures and pitfalls of this approach.

METHODS

Between September 2016 and January 2018, the authors performed eTOA in 9 patients with tumors involving Meckel’s cave and the middle cranial fossa. The lesions included trigeminal schwannoma in 4 patients, meningioma in 2 patients, metastatic brain tumor in 1 patient, chondrosarcoma in 1 patient, and dermoid cyst in 1 patient. In 7 of the 9 patients, eTOA alone was performed, while the other 2 patients underwent a combined eTOA and endoscopic endonasal approach or retrosigmoid craniotomy. Data including details of surgical techniques and clinical outcomes were recorded.

RESULTS

Gross-total resection was performed in 7 of the 9 patients (77.8%). Four patients underwent extended eTOA (with lateral orbital rim osteotomy). Drilling of the trapezoid sphenoid floor, a middle fossa “peeling” technique, and full visualization of Meckel’s cave were applied to approach the lesions. Tumors were exposed and removed extradurally in 3 patients and intradurally in 6 patients. There was no postoperative CSF leak.

CONCLUSIONS

The eTOA affords a direct route to access Meckel’s cave and middle cranial fossa lesions. With experience, this novel approach can be successfully applied to selected skull base lesions. To achieve successful removal of the tumor, emphasis should be placed on the importance of adequately removing the greater sphenoid wing and vertical crest. However, because of limited working space eTOA may not be an ideal approach for posterior fossa lesions.

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Ji Hoon Phi, Jin Hyun Kim, Kyoung Mi Eun, Kyu-Chang Wang, Ki Ho Park, Seung Ah Choi, Young Yim Kim, Sung-Hye Park, Byung-Kyu Cho and Seung-Ki Kim

Object

Supratentorial primitive neuroectodermal tumor (PNET) and medulloblastoma are highly malignant embryonal brain tumors. They share morphological similarities, but differ in their differentiation patterns and global gene expression. The authors compared the expression of specific genes involved in neuroglial differentiation in supratentorial PNETs and medulloblastomas to define the distinct characters of these tumors.

Methods

The mRNA expression of 8 genes (SOX2, NOTCH1, ID1, ASCL-1, NEUROD1, NEUROG1, NEUROG2, and NRG1) was evaluated in 25 embryonal tumors (12 supratentorial PNETs and 13 medulloblastomas) by quantitative real-time polymerase chain reaction. The expression levels of the transcripts of these genes were compared between the tumor groups. Activation of the JAK/STAT3 pathway was assessed by immunoblotting. Relative expression levels of STAT3 and phosphorylated STAT3 proteins were compared.

Results

Supratentorial PNETs expressed significantly higher levels of SOX2, NOTCH1, ID1, and ASCL-1 transcripts, whereas the transcription of proneural basic helix-loop-helix factors, NEUROD1, NEUROG1 (significantly), and NEUROG2 (not significantly) was upregulated in medulloblastomas. The proportion of phosphorylated STAT3α relative to STAT3α was significantly greater in supratentorial PNETs than in medulloblastomas, indicating activation of the JAK/STAT3 pathway in supratentorial PNETs.

Conclusions

These results indicate that supratentorial PNET predominantly has glial features and medulloblastoma largely follows a neuronal differentiation pattern. These divergent differentiation patterns may be related to the location and origin of each tumor.