Seung Ho Yang

Analysis of anatomical variations of bone and vascular structures around the posterior atlantal arch using three- dimensional computed tomography angiography

OBJECT The current study evaluates the incidence of anatomical variations of the V(3) segment of the vertebral artery (VA) and the posterior arch of the atlas (C-1). Failure to appreciate these types of anatomical variations can cause catastrophic injury to the VA during posterior approaches to the upper cervical spine. METHODS In the present study, the authors analyzed the records of 1013 Korean patients who underwent computed tomography (CT) angiography to evaluate the incidence of anomalous variations in the third segment of the VA and to determine the incidence and morphometric characteristics of any detected posterior ponticuli. The authors also hoped to determine any specific imaging features that might indicate a VA anomaly around the craniovertebral junction. RESULTS The mean age of the patients was approximately 55.7 years and the prevalence of a posterior ponticulus was 15.6%. The incidence rate of a posterior ponticulus in the male population was 19.3%, whereas in the female population it was 12.8%. The incomplete type of posterior ponticulus was more common than the complete type. The mean age of the patients with an incomplete posterior ponticulus (55.7 years) was significantly younger (p = 0.018) than the mean age of patients with a complete posterior ponticulus (57.6 years). The incidence rate of a persistent first inter-segmental artery was 4.7% and the incidence rate of a fenestrated VA was 0.6%. The area of the C-1 transverse foramen on the abnormal side was significantly smaller than that of the contralateral normal side. CONCLUSIONS The shape of the C-1 posterior arch and the third segment of the VA are heterogeneous. Therefore, preoperative radiological studies should be performed to identify any anatomical variations. Using preoperative 3D CT angiography, we can precisely identify an anomalous VA and significantly reduce the risk of VA injury.

Intraoperative Monitoring of Motor-Evoked Potentials for Supratentorial Tumor Surgery

Objective The purpose of this study was to assess the feasibility and clinical efficacy of motor evoked potential (MEP) monitoring for supratentorial tumor surgery. Methods Between 2010 and 2012, to prevent postoperative motor deterioration, MEP recording after transcranial stimulation was performed in 84 patients with supratentorial brain tumors (45 males, 39 females; age range, 24-80 years; median age, 58 years). MEP monitoring results were correlated with postoperative motor outcome compared to preoperative motor status. Results MEP recordings were stable in amplitude (<50% reduction in amplitude) during surgery in 77 patients (91.7%). No postoperative motor deficit was found in 66 out of 77 patients with stable MEP amplitudes. However, postoperative paresis developed in 11 patients. False negative findings were associated with edema in peri-resectional regions and postoperative bleeding in the tumor bed. MEP decrease in amplitude (>50%) occurred in seven patients (8.3%). However, no deficit occurred postoperatively in four patients following preventive management during the operation. Three patients had permanent paresis, which could have been associated with vascular injury during tumor resection. Conclusions MEP monitoring during supratentorial tumor surgery is feasible and safe. However, false negative MEP results associated with postoperative events may occur in some patients. To achieve successful monitoring, collaboration between surgeon, anesthesiologist and an experienced technician is mandatory.

Significance of Intracranial Pressure Monitoring after Early Decompressive Craniectomy in Patients with Severe Traumatic Brain Injury

Objective Early decompressive craniectomy (DC) has been used as the first stage treatment to prevent secondary injuries in cases of severe traumatic brain injury (TBI). Postoperative management is the major factor that influences outcome. The aim of this study is to investigate the effect of postoperative management, using intracranial pressure (ICP) monitoring and including consecutive DC on the other side, on the two-week mortality in severe TBI patients treated with early DC. Methods Seventy-eight patients with severe TBI [Glasgow Coma Scale (GCS) score <9] underwent early DC were retrospectively investigated. Among 78 patients with early DC, 53 patients were managed by conventional medical treatments and the other, 25 patients were treated under the guidance of ICP monitoring, placed during early DC. In the ICP monitoring group, consecutive DC on the other side were performed on 11 patients due to a high ICP of greater than 30 mm Hg and failure to respond to any other medical treatments. Results The two-week mortality rate was significantly different between two groups [50.9% (27 patients) and 24% (6 patients), respectively, p=0.025]. After adjusting for confounding factors, including sex, low GCS score, and pupillary abnormalities, ICP monitoring was associated with a 78% lower likelihood of 2-week mortality (p=0.021). Conclusion ICP monitoring in conjunction with postoperative treatment, after early DC, is associated with a significantly reduced risk of death.

Immunohistochemical Expression of DCUN1D1 in Non-small Cell Lung Carcinoma: Its Relation to Brain Metastasis

Purpose Non-small cell lung carcinoma (NSCLC) comprises 75-85% of all lung cancers, and approximately 25% of all NSCLC patients develop brain metastasis. There are no reliable markers for predicting in which patients this metastasis will occur. DCUN1D1, also known as squamous cell carcinoma-related oncogene, is associated with tumor progression and poor outcomes in NSCLC. The objective of this study was to investigate the role of DCUN1D1 expression in cases of brain metastasis due to NSCLC. Materials and Methods Primary tumor samples from a total of 71 cases of NSCLC, either with (n=40) or without (n=31) brain metastasis, were evaluated for DCUN1D1 expression by immunohistochemistry analysis. Results DCUN1D1 expression was detected in 16 patients (23%) and tended to correlate with T classification (15% of T1-2 tumors vs. 30% of T3-4 tumors, p=0.083). DCUN1D1 expression was significantly associated with tumor stage. It was observed in none of the patients with stage I disease, 10% of those with stage II disease, and 29% with stage III disease (p=0.009). In addition, 14 of 16 DCUN1D1-positive patients resulted in brain metastasis (p=0.01). The odds ratio of brain metastasis for patients with DCUN1D1 expression was 3.112 (p=0.009). Conclusion DCUN1D1 expression may play a role in tumor progression and development of brain metastasis in patients with NSCLC. Evaluation of DCUN1D1 expression may provide assistance in identifying those patients who are at higher risk for brain metastasis.

Significance of diffusion-weighted imaging and apparent diffusion coefficient maps for the evaluation of pyogenic ventriculitis

OBJECTIVE The aim of this study is to assess the significance of an apparent diffusion coefficient (ADC) modality for the diagnosis and follow-up evaluation of ventriculitis. PATIENTS AND METHODS Twelve patients with ventriculitis were enrolled in this study. Diffusion-weighted (DW) magnetic resonance images (MRI) and ADC maps of the periventricular white matter, intraventricular collections detected in the third or lateral ventricles and normal cerebrospinal fluid (CSF) were obtained. The images and ADC data from each lesion were correlated and then compared amongst the different lesions. CSF studies were performed via external ventricular drain (EVD) catheters or lumbar punctures performed on the same day as ADC mapping. Linear regression was used to analyze relationships among pleocytosis, glucose, chloride, protein content of pus, and ADC counting. RESULTS A total of 24 ADC values for intraventricular pus and CSF findings were obtained from 12 patients and analyzed. The DW MRI showed marked hyperintensity in purulent lesions, and the corresponding ADC maps revealed prominent hypointensity and decreased ADC values in dependent CSF compared with non-dependent CSF and normal white matter. Dependent CSF is defined as the CSF which is mixed with purulent discharge which is located at the lower portion of the ventricle by gravity. The correlations between ADC counting and pleocytosis, and also protein content were strong: r(2)=-0.84, r(2)=-0.62, respectively (p<0.001). CONCLUSION A decreased ADC value and increased signal intensity of dependent intraventricular fluid by DW MRI suggests the presence of material with restricted water diffusion in the ventricular space. This is seen in pyogenic ventriculitis when water diffusion is restricted in suppurative fluid. ADC counting is negatively correlated with pleocytosis and the protein content of CSF. Therefore, the ADC value might be a useful non-invasive method for the follow-up evaluation of ventriculitis as well as the diagnosis of it.

Surgical treatment of os odontoideum

Os odontoideum is a rare disease. There have been few reports of os odontoideum in the literature. In this study we retrospectively reviewed eight surgically treated patients. One patient underwent C1-2 transarticular screw fixation, five patients underwent C1-2 polyaxial screw and rod fixation and two patients with dystopic os odontoideum underwent occipito-cervical (O-C) fusion. Of the eight patients, neck pain was alleviated in seven (87.5%). Of the six patients who had neurological signs and symptoms, five (83.3%) exhibited neurological improvement. Radiologically, solid fusion was observed in seven patients (87.5%). Active surgical treatment should be considered even in patients with os odontoideum who exhibit mild symptoms. In most patients with os odontoideum, use of the C1-2 polyaxial screw and rod technique may be the most appropriate treatment. In patients with dystopic os odontoideum, O-C fusion should be considered.

MicroRNA-200 family members and ZEB2 are associated with brain metastasis in gastric adenocarcinoma

Although the incidence of brain metastasis in gastric cancer is relatively low, its prevalence may increase with improved therapy and longer survival tumors. The molecular mechanisms underlying brain metastases are not well understood. To gain insight into the mechanism of brain metastasis, we studied differences in microRNA (miRNA) expression levels in 8 cases of matched primary gastric adenocarcinoma and brain metastatic adenocarcinoma using the Illumina microRNA microarray chip. We identified 6 upregulated and 2 downregulated miRNAs in all 8 cases simultaneously. Interestingly, 2 out of 8 miRNAs (hsa-miR‑141-3p and hsa-miR-200b-3p) belonged to the miR-200 family. Online microRNA database searching revealed that ZEB2 is the top-ranked target gene for hsa-miR141-3p and hsa-miR-200b-3p, prompting us to focus ZEB2 expression in brain metastatic adenocarcinoma. We confirmed that ZEB2 expression was markedly downregulated in some brain metastatic samples. In addition, decreased ZEB2 expression was noted by western blot analysis of 2 metastatic gastric adenocarcinoma cell types that were derived by in vivo selection following intracardiac injection of gastric cancer cell lines. In conclusion, we demonstrate that expression of miRNA-200 family members and ZEB2 are associated with brain metastases of gastric adenocarcinoma, not only in matched patient samples, but also in metastatic cell lines that were derived by in vivo selection.

Cerebellar Hemorrhage after Burr Hole Drainage of Supratentorial Chronic Subdural Hematoma

Cerebellar hemorrhage is an unusual complication of supratentorial neurosurgery. To the best of our knowledge, only three case reports have described the occurrence of cerebellar hemorrhage after burr hole drainage for the treatment of chronic subdural hematoma (SDH). We present the case of a patient with this rare postoperative complication of cerebellar hemorrhage after burr hole drainage of a chronic SDH. Although burr hole drainage for the treatment of chronic SDH is rare complication, it is necessary to be aware of the possibility of cerebellar hemorrhage after supratentorial surgery, even with limited surgery such as burr hole drainage of a chronic SDH.

Posterior C1 Stabilization Using Superior Lateral Mass as an Entry Point in a Case With Vertebral Artery Anomaly: Technical Case Report

BACKGROUND AND IMPORTANCE: This is the first report of using the superior lateral mass as an alternative starting point for C1 posterior screw placement, demonstrating the importance of recognizing vertebral artery (VA) anomaly in deciding the surgical strategy for C1 screw placement. CLINICAL PRESENTATION: A 56-year-old man presented with severe neck pain after a fall. Imaging demonstrated an unstable bursting fracture at C4, C1-2 instability, and a subluxation at C2-3. Computed tomography angiography indicated that the persistent first intersegmental artery was located on the left side. The patient underwent anterior-posterior cervical fixation and fusion. Posterior C1 fixation was done with polyaxial screw rod construct using C1 superior lateral mass on the left side and C1 inferior lateral mass on the right side. The patient had no immediate postoperative deficits. At the 8-month follow-up examination, the patient was neurologically intact with a solid cervical fusion. CONCLUSION: The third segment of the VA is heterogeneous; therefore, preoperative radiologic studies should be performed to identify any anatomical variations. Using preoperative 3-dimensional computed tomography angiography, we can precisely identify an anomalous VA, thereby significantly reducing the risk of VA injury. To avoid significant morbidities associated with VA injury, a more optimal entry point for C1 fixation can be selected if a persistent first intersegmental artery or fenestrated VA is detected.

The effect of patient age on the internal carotid artery location around the atlas

OBJECT The aim of this study was to analyze the exact location of the internal carotid artery (ICA) relative to the C-1 lateral mass and describe the effect of age on the tortuosity of the ICA. METHODS The authors analyzed 641 patients who had undergone CT angiography to evaluate the location of the ICA in relation to the C-1 lateral mass. Each patient was assigned to 1 of 3 age groups (< 41 years, 41-60 years, and > 60 years of age). The degree of lateral positioning of the ICA was classified into 4 groups: Group 1 (lateral to the C-1 lateral mass), Group 2 (lateral half of the lateral mass), Group 3 (medial half of the lateral mass), or Group 4 (medial to the lateral mass). The anteroposterior relationship of the ICA was classified into Group A (posterior to the anterior tubercle) or Group B (anterior to the anterior tubercle). Distances from the ICA to the midline, anterior tubercle, and anterior cortex of the lateral mass were measured. Distances between the lateral margin of the lateral mass and the longus capitis muscle were also evaluated. RESULTS The prevalence of the ICA located in front of the lateral mass (Groups 2 and 3) was 47.4% overall. The position of the ICA changes with age due to vessel tortuosity. Only 18.3% of patients in the youngest age group (< 41 years of age) had an ICA in front of the lateral mass (Group 2 or 3 area). However, this percentage increased in the older 2 groups (43.5% in the 41-60 year old group, and 57% in the > 60-year-old age group). The mean distance from the midline to the ICA was 22.6 mm, and the mean distance from the ICA to the C-1 anterior tubercle and the ventral cortex of the lateral mass was 4.7 and 4.5 mm, respectively. Moreover, the ICA is more prone to injury during bicortical C-1 screw placement when the longus capitis muscle is hypotrophic and does not cover the entire ventral surface of the lateral mass. CONCLUSIONS Elderly patients have a higher incidence of a medially located ICA that may contribute to the risk of injury to the ICA during bicortical C-1 screw or C1-2 transarticular screw placement. Although the small number of reported cases of ICA injury does not allow for determination of a direct relationship with specific anatomical characteristics, the presence of unfavorable anatomy does warrant serious consideration during evaluation for C-1 screw placement in elderly patients.