Learning curve of trans-sacral epiduroscopic laser decompression in herniated lumbar disc disease.

BACKGROUND: Trans-sacral epiduroscopic laser decompression (SELD) using slender epiduroscope and a holmium YAG laser is one of the minimally invasive surgical options for lumbar disc herniation. However, the learning curve of SELD and the effect of surgical proficiency on clinical outcome have not yet been established. We investigated patients with lumbar disc herniation undergoing SELD to report the clinical outcome and learning curve. METHODS: Retrospective analysis of clinical outcome and learning curve were performed at a single center from clinical data collected from November 2015 to November 2018. A total of 82 patients who underwent single-level SELD for lumbar disc herniation with a minimum follow-up of 6.0 months were enrolled. Based on the findings that the cut-off of familiarity was 20 cases according to the cumulative study of operation time, patients were allocated to two groups: early group (n = 20) and late group (n = 62). The surgical, clinical, and radiological outcomes were retrospectively evaluated between the two groups to analyze the learning curve of SELD. RESULTS: According to linear and log regression analyses, the operation time was obtained by the formula: operation time = 58.825-(0.181 × [case number]) (p < 0.001). The mean operation time was significantly different between the two groups (mean 56.95 min; 95% confidence interval [CI], 49.12-64.78 in the early group versus mean 45.34 min; 95% CI, 42.45-48.22 in the late group; p = 0.008, non-parametric Mann-Whitney U test). Baseline characteristics, including demographic data, clinical factors, and findings of preoperative magnetic resonance imaging, did not differ between the two groups. Also, there was no significant difference in terms of surgical outcomes, including complication and failure rates, as well as clinical and radiological outcomes between the two groups. CONCLUSION: The learning curve of SELD was not as steep as that of other minimally invasive spinal surgery techniques, and the experience of surgery was not an influencing factor for outcome variation.

Dose-Dependent Cytotoxicity of Gold Nanoparticles on Human Neural Progenitor Cells and Rat Brain.

Gold nanoparticles (GNPs) are utilized as diagnostic and therapeutic tools to detect and treat human disease. Researchers in the field of nanotoxicity are working to determine the physicochemical properties of nanoparticles that lead to toxicity in an effort to establish safe design rules. In this study, we performed the MTT and terminal transferase dUTP nick end labeling (TUNEL) assays to verify the cytotoxicity of GNPs on rat brain tissue and human neural progenitor cells (NPCs). As results, we observed that GNPs induced apoptosis in NPCs. NPCs were markedly damaged following the administration of 200 µM and 2 mM GNPs, whereas 2 µM GNPs showed slightly increased damage relative to that of the control. In addition, TUNEL-positive cells were densely distributed at regions surrounding the GNP injection site in the brain 7 days after the GNPs injection. During long-term GNPs exposure, TUNEL-positive cells were rarely observed in the cerebral cortex. In this study, we observed that apoptosis increased in proportion to GNP concentrations in the brain and in cultivated NPCs. These result suggest that large GNPs (<100 nm) are toxic and that the cytotoxicity increased as the concentration of GNPs increased in NPCs or in the brain.

Gradual expansion of stent retriever in mechanical thrombectomy for curved middle cerebral artery: structural findings of the stent for predictable recanalization results.

BACKGROUND: Trevo Provue stent retriever with visible struts under fluoroscopy may be useful in identifying the optimal position and expansion of the stent during the procedure. This study aimed to demonstrate and analyze changes in the segmental diameter of a radio-opaque stent retriever after deployment according to recanalization results, and its relationship with the angle of the occluded segment of the middle cerebral artery (MCA). METHODS: Forty-one patients who underwent mechanical thrombectomy using a Trevo stent retriever were divided into two groups according to Thrombolysis in Cerebral Infarction (TICI) score (TICI 0-2a and TICI 2b/3). The proximal (Pt), middle (Mt), and distal diameter (Dt) of the deployed stent, at three post-deployment waiting times (t = 0, 3, and 5 min), were measured, and ratios of Mt to Pt (Mt/Pt) and of Mt to Dt (Mt/Dt) were calculated. RESULTS: TICI 2b/3 was achieved in 31 patients (75.6%) and TICI 0-2a in 10 patients (24.4%). In the TICI 2b/3 group, both changes of Mt/Pt (P < 0.001) and Mt/Dt (P = 0.001) until 3 min were significant and all Mt/Pt (each P < 0.01), M3/D3 (P = 0.014), and M5/D5 (P = 0.012) were significantly larger than those in the TICI 0-2a group. The angle of the MCA was significantly correlated with Mt/Pt and Mt/Dt (P < 0.001). CONCLUSION: The diameter of the stent retriever after deployment was associated with the recanalization results in mechanical thrombectomy following MCA occlusion.

Relationships between Head Circumference Percentile, Lumbar Puncture Pressure, and Cerebrospinal Fluid Space in Young Children: Increased Cerebrospinal Space and Pressure May Result in Compensatory Enlargement of Head Circumference Only in the Infant Period.

BACKGROUND: The aim of this study was to retrospectively evaluate and analyze the relationships between head circumference percentile (HCP), lumbar puncture pressure (LPP), and cerebrospinal fluid (CSF) space. METHODS: The 88 patients were divided into 3 age groups (group 1, up to 12 months; group 2, 12-36 months; group 3, 36-72 months). RESULTS: In group 1 (n = 40), there was a significant positive correlation of the HCP with the LPP (r =0.414, p =0.008), Evans ratio (r =0.365, p =0.021), and thickness of subdural hygroma (SDHG; r =0.403, p =0.010). Group 2 (n = 29) revealed a significant positive correlation between the LPP and the thickness of SDHG (r =0.459, p =0.012). Group 3 (n = 19) showed no significant correlation among these factors. Overall, age was related with SDHG thickness both in infants and toddlers, while HCP was related with LPP, Evans ratio, and SDHG thickness only in infants, and LPP was related with SDHG thickness only in toddlers. CONCLUSION: We suggest that increased cerebrospinal space and pressure may result in compensatory enlargement of head circumference only in the infant period, and the SDHG thickness decreases with age during the infant and toddler phases.

Voxel-based statistical analysis of brain metabolism in patients with growth hormone deficiency after traumatic brain injury.

OBJECTIVE: The aim of this study was to investigate the regional cerebral metabolism related to growth hormone deficiency (GHD) after traumatic brain injury (TBI) using F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) images. METHODS: Twenty-three patients with diffuse axonal injury following TBI were enrolled. They underwent brain F-18 FDG PET study and an insulin tolerance test (ITT). According to the results of ITT, they were divided into two groups: patients with GHD and subjects with TBI but normal Growth Hormone (GH). Voxel-based statistical analysis was performed and the regional cerebral glucose metabolism shown on F-18 FDG PET from 10 patients with GHD was compared with those from 13 patients without GHD. Analysis was performed using SPM2 to identify regions where decreased changes in regional cerebral glucose metabolism were significantly related to GHD. RESULTS: Compared with subjects with TBI but normal GH, patients with GHD after TBI showed decreased cerebral glucose metabolism in the Left superior frontal gyrus, Right angular gyrus, Right superior temporal gyrus, Left inferior temporal gyrus, Left anterior and middle cingulate gyrus and Right anterior and middle cingulate gyrus. (puncorrected < 0.005). CONCLUSIONS: The findings are suggestive of the brain region influenced by GHD. These cortical areas are involved in regulation of intellectual function, executive function and working memory.

Cytotoxicity of Gold Nanorods and Nanowires on Cultivated Neural Precursor Cells.

Given the emergence of nanotherapeutics and nanodiagnostics as key tools in today's medicine, it has become of critical importance to define the interactions of nanomaterials with biological systems. The biomedical applications of nanoparticles (NPs) in chemical sensing, biological imaging, drug delivery, photothermal therapy and cancer treatment have been demonstrated. Gold NPs as new biomedical tools are the focus of research due to their ease of synthesis, chemical stability and unique optical properties. Therefore, there is a need to establish the toxicity, side effects and safety of gold NPs for human applications. To study the in vitro cytotoxicity of gold NPs, we performed MTT assay using two types of gold NPs such as gold nanorods (GNRs) and gold nanowires (GNWs). The percentage cytotoxicity of damaged neural precursor cells (NPCs) that were treated with 100 mg GNRs was 97.5±3.9%; and proportion of damaged NPCs following the administration of the same dose of GNWs was 98.8±0.3%. The cytotoxicity of 10 mg GNRs in NPCs was 54.4±8.3%, whereas it was 98.7±0.6% for the same dose of GNWs. Then, to verify that gold NPs induced apoptotic cell death in NPCs, the LIVE/DEAD Viability/Cytotoxicity assay was performed. We observed that cell death of NPCs increased with an increase in quantity of both types of gold NPs. Cell viability assessed the overall dose-dependent toxicity of NPs in cultured cells. As the results suggest, this study demonstrated that treatment with gold NPs resulted in cellular toxicity in a dose-dependent manner in cultured NPCs.

Four French sheath-based transradial cerebral angiographies in the elderly: A single neurointerventionalist's experience.

BACKGROUND: Catheter angiography via transradial access (TRA) is better at reducing access site complications and morbidity than via transfemoral access (TFA). The rate of periprocedural complications increases in elderly populations and using a smaller sheath can help reduce access site complications. The aim of this study was to assess the feasibility and safety of 4 F sheath-based TRA cerebral angiography in elderly patients (≥65 years) and compare it to TFA cerebral angiography. METHODS: The medical records of elderly patients undergoing diagnostic cerebral angiography with a single neurointerventionalist via TRA (57 cases, from July 2019 to December 2020) versus TFA (69 cases, from January 2018 to June 2019) were retrospectively reviewed. All TRA angiographies were performed via right radial artery access with a 4 F sheath and a 4 F Simmons 2 catheter. RESULTS: There were no significant differences (TRA vs. TFA) in age (71.1 ± 4.0 vs. 72.1 ± 4.6 years, p = 0.189), accessed vessels (3.9 ± 0.5 vs. 3.9 ± 0.6, p = 0.852), fluoroscopy time (7.1 ± 3.3 vs. 7.6 ± 3.5 min, p = 0.068), and radiation exposure (42.1 ± 15.8 vs. 47.0 ± 13.7 Gy-cm2, p = 0.067). However, the procedure duration was significantly shorter in the TRA group (17.2 ± 3.9 vs. 19.0 ± 6.0 min, p = 0.003). Painful groin hematoma occurred in 2 of the 69 cases (2.9%) in the TFA group. In the TRA group, access site complications were not occurred; however, catheter kinks occurred in 2 of 57 cases (3.5%). CONCLUSIONS: The 4 F sheath-based TRA is a feasible option for diagnostic cerebral angiography in elderly patients. However, care should be taken during catheter manipulation.

Morphological and molecular expression patterns of neural precursor cells derived from human fetal spinal cord in two-, three-dimensional, and organoid culture environments.

Recently, interest in three-dimensional (3D) cell or tissue organoids that may, in vitro, overcome not only the practical problems associated with fetal tissue transplantation, but also provide a potential source for the regeneration of injured spinal cords, has been increasing steadily. In this study, we showed that human neural precursor cells (hNPCs) derived from the fetal spinal cord could be incubated in serum free medium at two dimensional (2D), three dimensional (3D) and tissue organoid-systems. Additionally, we investigated morphological changes over time along with the expression of proteoglycans, collagen, or myelin in 2D, 3D and tissue-like organoids. 2D cells exhibited a spindle-shaped morphology with classic hill and valley growth patterns, while 3D cells grew as clusters of undifferentiated cells and cell sheets (tissue organoids) that gradually rolled up like a carpet without forming a circular cell mass. Immunostaining was performed to demonstrate the expression of TUJ-1, MAP-2, GAD 65/67 and ChAT in 2D cells or tissue-like organoids, which stained positively for them. In addition, we observed the immunoreactivity of HNu, NG2, TUJ-1, and GFAP in tissue-like organoids. The organoid culture system studied in our work may be used as therapeutic agents for spinal cord injury (SCI), and as raw materials needed for development of new medicines to improve human responses and cure diseases.

Treatment Outcome of the Brain Metastases in Peri-Rolandic Area: Comparison Between Surgery and Stereotactic Radiosurgery.

BACKGROUND: Brain metastases of peri-Rolandic area is crucial as it directly impacts the quality of life for cancer patients. Surgery or stereotactic radiosurgery (SRS) is considered for peri-Rolandic brain metastases as for other brain metastases. However, the benefit of each treatment modality on functional outcome has not been clearly defined for this tumor. The purpose of this study is to compare the functional course of each treatment and to suggest an effective treatment for patients' quality of life. METHODS: Fifty-two patients who had undergone SRS or surgery for brain metastasis confirmed by enhanced MRI were enrolled retrospectively. Overall survival (OS), progression free survival (PFS), and functional outcomes were estimated using the Kaplan-Meier method, univariate, multivariate analysis, and Cox proportional hazards regression. RESULTS: Median OS and PFS were 13.3 months and 8.9 months in our study population. Treatment modalities were not significant factors for OS and PFS. Extracranial systemic cancer progression was significant factor for both parameters (p=0.030 for OS and p=0.040 for PFS). Median symptom improvement (improvement of at least 1 grade after surgery compared to preoperative state) time was significantly shorter in surgery group than in the SRS group (10.5 days vs. 37.5 days, p=0.034). CONCLUSION: Surgery for brain metastases can contribute to a positive quality of life for the remaining duration of the patient's life.

Crush cytologic findings of a cerebral granular cell astrocytoma.

BACKGROUND: Granular cell astrocytoma (GCA) is a rare variant of astrocytoma, characterized by an aggressive prognosis compared to conventional astrocytomas of the same World Health Organization grade. Intraoperative smears provide useful clues in diagnosing neuropathology, especially in rarely encountered central nervous system tumors. CASE: The patient was a 53-year-old man who presented with a huge mass at the left temporal lobe with peritumoral edema on MRI. The crush smears revealed singly-scattered, large eosinophilic cells with eccentrically located nuclei as well as plump, finely-granular cytoplasm with distinct borders. Mild cellular atypia and absence of mitotic activity were noted. These cells were admixed with small mature lymphoid cells. Histology showed scattered large granular cells which were positive for glial fibrillary acidic protein. CONCLUSION: The most helpful imprint cytologic findings of GCA were as follows: (1) large cells containing eosinophilic granular cytoplasm rather than the foamy or bubbly cytoplasm associated with macrophages or renal cell carcinomas; (2) distinct granular cell borders in contrast to the ruffled membrane of macrophages, and (3) markedly large-sized granular cells, ranging from 60 to 100 µm in diameter.

Radiotherapy for brain metastasis and long-term survival.

Patients with brain metastases (BM) can benefit from radiotherapy (RT), although the long-term benefits of RT remain unclear. We searched a Korean national health insurance claims database and identified 135,740 patients with newly diagnosed BM during 2002-2017. Propensity score matching (PSM) was used to evaluate survival according to RT modality, which included whole-brain radiotherapy (WBRT) and/or stereotactic radiosurgery (SRS). The 84,986 eligible patients were followed for a median interval of 6.6 months, and 37,046 patients underwent RT (43.6%). After the PSM, patients who underwent RT had significantly better overall survival after 1 year (42.4% vs. 35.3%, P < 0.001), although there was no significant difference at 2.6 years, and patients who did not undergo RT had better survival after 5 years. Among patients with BM from lung cancer, RT was also associated with a survival difference after 1 year (57.3% vs. 32.8%, P < 0.001) and a median survival increase of 3.7 months. The 1-year overall survival rate was significantly better for SRS than for WBRT (46.4% vs. 38.8%, P < 0.001). Among Korean patients with BM, especially patients with primary lung cancer, RT improved the short-term survival rate, and SRS appears to be more useful than WBRT in this setting.

Comparison of Long-Term Angiographic Results of Wide-Necked Intracranial Aneurysms : Endovascular Treatment with Single-Microcatheter Coiling, Double-Microcatheter Coiling, and Stent-Assisted Coiling.

OBJECTIVE: Endovascular treatment of intracranial aneurysms is challenging in case of wide-necked aneurysms because coils are prone to herniate into the parent artery, causing thromboembolic events or vessel occlusion. This study aims to compare long-term angiographic results of wide-necked aneurysms treated by stent-assisted, double-microcatheter, or single-microcatheter groups. METHODS: Between January 2003 and October 2016, 108 aneurysms that were treated with endovascular coil embolization with a neck size wider than 4 mm and a follow-up period of more than 3 years were selected. We performed coil embolization with single-microcatheter, double-microcatheter, and stent-assisted techniques. Angiographic results were evaluated using the Raymond-Roy occlusion classification (RROC). All medical and angiographic records were reviewed retrospectively. RESULTS: Clinical and angiographic analyses were conducted in 108 wide-necked aneurysms. The immediate post-procedural results revealed RROC class I (complete occlusion) in 66 cases (61.1%), class II (residual neck) in 36 cases (33.3%), and class III (residual sac) in six cases (5.6%). The final follow-up results revealed class I in 48 cases (44.4%), class II in 49 cases (45.4%), and class III in 11 cases (10.2%). Of a total of 45 (41.6%) radiologic recurrences, there were 21 cases (19.4%) of major recurrence that required additional treatment, and 24 cases (22.2%) of minor recurrence. The final follow-up angiographic results showed statistically significant differences between the stent-assisted group and the others (p<0.01). CONCLUSION: Long-term follow-up angiography demonstrated that the stent-assisted technique had a better complete occlusion rate than the other two techniques.

Usefulness of Dual Volume Reconstruction of Threedimensional Rotational Angiography in the Surgical Treatment of Spinal Vascular Malformations: Assessment of Image Similarity Between Angiography and Microscopy.

AIM: To describe and demonstrate the close analogy between dual volume reconstruction images derived using three-dimensional digital subtraction angiography (3D-DSA) and surgical microscopic images. MATERIAL AND METHODS: From 2013 to 2018, 12 patients with spinal vascular malformation (SVM) underwent preoperative 3D-DSA with dual volume reconstruction followed by surgery for the SVM without prior endovascular treatment. Two spinal neurosurgeons involved in each operation were surveyed regarding the similarity between the dual volume images of 3D-DSA and the surgical microscopic images with respect to the following four aspects: (1) relationship between bony structures and the entry artery going to the feeder; (2) feeding artery; (3) shunting point or nidus location; and (4) draining vein. RESULTS: The patients were diagnosed with spinal dural arteriovenous fistulas (n=8) and spinal arteriovenous malformations (n=4). Two, six, and four lesions showed cervical, thoracic, and lumbar area distribution, respectively. All operations were successful and without complications. The correspondence between dual volume images and intraoperative microscopic images, with respect to bony structure and entry artery, showed perfect reliability (k=1.000; p=0.000) and a high level of similarity in all cases. With respect to the feeding artery, shunt point/nidus location, and draining vein, there was substantial reliability between the operator and the observer (k=0.750; p=0.045). CONCLUSION: Images obtained using the dual volume reconstruction technique of the 3D-DSA exhibit a reliable similarity to real microscopic images and are useful in the surgical treatment of SVMs with respect to surgical planning, targeting, and orientation.

Efficacy and safety of decompressive craniectomy with non-suture duraplasty in patients with traumatic brain injury.

BACKGROUND: Decompressive craniectomy is an important surgical treatment for patients with severe traumatic brain injury (TBI). Several reports have been published on the efficacy of non-watertight sutures in duraplasty performed in decompressive craniectomy. This study sought to determine the safety and feasibility of the non-suture dural closure technique in decompressive craniectomy. METHODS: A total of 106 patients were enrolled at a single trauma center between January 2017 and December 2018. We retrospectively collected data and classified the patients into non-suture and suture duraplasty craniectomy groups. We compared the characteristics of patients and their intra/postoperative findings such as operative time, blood loss, imaging findings, complications, and Glasgow Outcome Scale scores. RESULTS: There were 37 and 69 patients in the non-suture and suture duraplasty groups, respectively. There were no significant differences between the two groups concerning general characteristics. The operative time was significantly lower in the non-suture duraplasty group than in the suture duraplasty group (150 min vs. 205 min; p = 0.002). Furthermore, blood loss was significantly less severe in the non-suture duraplasty group than in the suture duraplasty group (1000 mL vs. 1500 mL; p = 0.028). There were no other significant differences. CONCLUSION: Non-suture duraplasty involved shorter operative times and less severe blood losses than suture duraplasty. Other complications and prognoses were similar across groups. Therefore, the non-suture duraplasty in decompressive craniectomy is a safe and feasible surgical technique.

Idiopathic Pseudoaneurysm of External Carotid Artery with Delayed Facial Palsy After Covered Stenting.

BACKGROUND: Idiopathic pseudoaneurysms of the external carotid artery (ECA) between the internal maxillary artery and the facial artery are rare. Endovascular covered stenting is an alternative method for surgically challenging cases; however, movable and flexible vessels may prevent the maintenance of the stent. CASE DESCRIPTION: A 26-year-old woman presented with sudden swelling and pain of the left chin due to a pseudoaneurysm of the proximal ECA trunk. She had undergone endovascular covered stenting and suddenly developed facial palsy at postprocedural 1 week. Regrowth of the aneurysm and slippage of the stent were detected, and additional stenting was performed. Swelling and pain of the chin and neck and subsequently the facial palsy completely resolved, and the patient made a full recovery. CONCLUSIONS: The ECA aneurysm between the internal maxillary artery and facial artery may be more floating and changeable than any other portions of the ECA, and regrowth of the ECA aneurysm may cause delayed complication. In addition, knowledge of the mechanism is necessary to help in the endovascular treatment.

Sagittal alignment correlates with the C1-C2 fixation angle and functional outcome after posterior atlantoaxial fixation for traumatic atlantoaxial instability.

The C1-C2 angle has been shown to correlate with subaxial alignment under various conditions. The aim of this study was to evaluate the correlation between the C1-C2 fixation angle and subaxial sagittal alignment as well as the impact of the sagittal vertical axis (SVA) on functional outcomes in traumatic atlantoaxial (A-A) instabilities. The data of 36 patients who underwent posterior C1-C2 fixation for traumatic A-A instability between December 2005 and September 2015 were retrospectively reviewed. Radiographic parameters, including the C1-C2 angle, occipitocervical angle, C2-C7 angle, and C2-C7 SVA, were measured before surgery and at 1-year follow-up. Clinical outcomes were measured using the visual analogue scale (VAS) and Neck Disability Index (NDI). The preoperative and postoperative relationships between parameters were analyzed. In preoperative and postoperative radiographs, the C1-C2 angle correlated with the C2-C7 angle (r = -0.347, p = 0.038, and r = -0.339, p = 0.043, respectively) and the C2-C7 SVA (r = 0.648, p < 0.001, and r = 0.436, p = 0.008, respectively). The postoperative C2-C7 SVA was directly proportional to the preoperative C2-C7 SVA and postoperative C1-C2 angle (postoperative C2-C7 SVA = 0.72 + 0.669 × [preoperative C2-C7 SVA] + 0.555 × [postoperative C1-C2], r2 = 0.677, p < 0.001). The postoperative C2-C7 SVA correlated with postoperative VAS (rs = 0.382, p = 0.021) and NDI (rs = 0.476, p = 0.003). The postoperative C2-C7 SVA was affected by the preoperative C2-C7 SVA and the postoperative C1-C2 angle and showed significant positive correlation with postoperative NDI. The C1-C2 fixation angle and the preoperative C2-C7 SVA should be carefully considered to avoid postoperative sagittal imbalance.

Practical Dose Parameter Values for the Prediction of the Adverse Effect of Neurointerventional Radiation: Relationship Between the Dose Parameters and Temporary Alopecia After Intracranial Coil Embolization.

OBJECTIVE: To present values for the dose parameters predictive of alopecia as an adverse effect induced by neuroembolization using a biplane fluoroscopy. METHODS: This study included a total of 151 patients (52 men, mean age of 55.1 ± 12.2 years) treated for intracranial neuroembolization between 2014 to 2018 with the following criteria: 1) obtainable dose report with digital subtraction angiographic image records, 2) no history of radiation exposure 6 months prior to the first procedure, and 3) and clinical follow-up performed through 12 months following the procedure. Patients were divided into 2 groups according to their presentation of alopecia during the follow-up period. RESULTS: Eighteen (11.9%) patients developed alopecia 10 to 30 days after the procedure (average: 18.5 ± 5.3 days). Sixteen (88.9%) patients in the alopecia group were affected by projection of the A-plane fluoroscopy. Area under the receiver operating characteristic analysis curves of 0.865 (P = 0.000) and 0.831 (P = 0.000) were used to compute the optimal A-plane dose area product (255.4 Gy-cm2; sensitivity: 0.875; specificity: 0.805; Youden J = 0.682) and cumulative dose (4437.5 mGy; sensitivity, 0.750; specificity, 0.805; Youden J = 0.556) cutoff values, respectively, capable of distinguishing patients with alopecia (n = 16) from subtotal patients (n = 149). CONCLUSIONS: The dose area product and the cumulative dose may be useful, intuitive factors for predicting the adverse effects of the neurointerventional radiation. Further multicenter research should be performed to confirm the efficacy and utility of the reference values of dose area product and cumulative dose for preventing excessive irradiation during neurointerventional procedures.

Intraoperative Frozen Cytology of Central Nervous System Neoplasms: An Ancillary Tool for Frozen Diagnosis.

BACKGROUND: Pathologic diagnosis of central nervous system (CNS) neoplasms is made by comparing light microscopic, immunohistochemical, and molecular cytogenetic findings with clinicoradiologic observations. Intraoperative frozen cytology smears can improve the diagnostic accuracy for CNS neoplasms. Here, we evaluate the diagnostic value of cytology in frozen diagnoses of CNS neoplasms. METHODS: Cases were selected from patients undergoing both frozen cytology and frozen sections. Diagnostic accuracy was evaluated. RESULTS: Four hundred and fifty-four cases were included in this retrospective single-center review study covering a span of 10 years. Five discrepant cases (1.1%) were found after excluding 53 deferred cases (31 cases of tentative diagnosis, 22 cases of inadequate frozen sampling). A total of 346 cases of complete concordance and 50 cases of partial concordance were classified as not discordant cases in the present study. Diagnostic accuracy of intraoperative frozen diagnosis was 87.2%, and the accuracy was 98.8% after excluding deferred cases. Discrepancies between frozen and permanent diagnoses (n = 5, 1.1%) were found in cases of nonrepresentative sampling (n = 2) and misinterpretation (n = 3). High concordance was observed more frequently in meningeal tumors (97/98, 99%), metastatic brain tumors (51/52, 98.1%), pituitary adenomas (86/89, 96.6%), schwannomas (45/47, 95.8%), high-grade astrocytic tumors (47/58, 81%), low grade astrocytic tumors (10/13, 76.9%), non-neoplastic lesions (23/36, 63.9%), in decreasing frequency. CONCLUSIONS: Using intraoperative cytology and frozen sections of CNS tumors is a highly accurate diagnostic ancillary method, providing subtyping of CNS neoplasms, especially in frequently encountered entities.

Fractionated Stereotactic Radiosurgery for Brain Metastases Using the Novalis Tx® System.

OBJECTIVE: To evaluate the efficacy of fractionated stereotactic radiosurgery (FSRS) performed using the Novalis Tx® system (BrainLAB AG, Feldkirchen, Germany; Varian Medical Systems, Palo Alto, CA, USA) for brain metastases. METHODS: Between March 2013 and July 2016, 23 brain metastases patients were admitted at a single institute. Twenty-nine lesions too large for single session stereotactic radiosurgery or located in the vicinity of eloquent structures were treated by FSRS. Based on the results obtained, we reviewed the efficacy and toxicity of FSRS for the treatment of brain metastases. RESULTS: The most common lesion origin was lung (55%) followed by breast (21%). Median overall survival was 10.0 months (95% confidence interval [CI], 4.9-15.0), and median progression-free survival was 10.0 months (95% CI, 2.1-13.9). Overall survival rates at 1 and 2 years were 58.6% and 36.0%, respectively. Local recurrence and neurological complications affecting morbidity each occurred in two cases. CONCLUSION: FSRS using the Novalis-Tx® system would appear to be an effective, safe noninvasive treatment modality for large and eloquently situated brain metastases. Further investigation is required on a larger number of patients.

Factors Related to the Development of Shunt-Dependent Hydrocephalus Following Subarachnoid Hemorrhage in the Elderly.

AIM: Surgical procedures for aneurysmal subarachnoid hemorrhage (SAH) are increasing among the elderly as the population ages. Chronic shunt-dependent hydrocephalus is a recognized complication of SAH. The aim of this study was to identify predictive factors for the development of shunt-dependent hydrocephalus among elderly patients with SAH. MATERIAL AND METHODS: We retrospectively studied 878 patients, including 275 patients ? 65 years old, with SAH treated between 2005 and 2015 to identify factors contributing to the development of shunt-dependent hydrocephalus. The relationships between shunt-dependent hydrocephalus and the causative factors were analyzed using univariate and multivariate analysis; the causative factors were based on the results of previous studies. RESULTS: In the 878 patients with SAH, there was a significant difference in the incidence of shunt-dependent hydrocephalus between patients < 65 years old and those ? 65 years old (p=0.021). In the 275 patients ? 65 years old, the following were associated with shunt-dependent hydrocephalus on univariate analysis: 1) Hunt and Hess grade (p=0.005), 2) Fisher grade (p < 0.001), 3) intraventricular hemorrhage (p < 0.001), 4) acute hydrocephalus (p=0.003), 5) aneurysm location (p=0.001), and 6) external ventricular drain placement (p < 0.001). On multivariate analysis, only 1) intraventricular hemorrhage (p < 0.001) and 2) a ruptured aneurysm located in the distal posterior circulation (p=0.014) were related to an increased risk for the development of shunt-dependent hydrocephalus. CONCLUSION: Evaluating risk factors can help identify patients at high risk of developing shunt-dependent hydrocephalus. Identifying these risk factors may help neurosurgeons to provide optimal therapy and improve outcomes in patients with SAH.