A Comprehensive Revision of Radiation Immunotherapy and the Abscopal Effect in Central Nervous System Metastases: Reassessing the Frontier.

Seventy years ago, Robin Mole introduced the concept of the abscopal effect to describe a rare phenomenon. This occurs when local radiation triggers an immune-mediated reduction in tumors outside the treated area but within the same organism. Observing this effect has been linked to improved overall and progression-free survival in patients who experience it. While the abscopal effect was once considered rare, it is now being observed more frequently due to the combination of radiation with immunotherapy. As a result, more researchers are exploring this study area, which shows promise for excellent results. This review focuses explicitly on the immunological implications of activating the abscopal effect through ionizing radiation in the central nervous system and explores the potentially involved immunological pathways.

Comparison of microvascular decompression, percutaneous radiofrequency rhizotomy, and stereotactic radiosurgery in the treatment of trigeminal neuralgia: A long term quasi-experimental study.

BACKGROUND: Microvascular decompression (MVD), radiofrequency rhizotomy (RFR), and stereotactic radiosurgery (SRS) are surgical techniques frequently used in the treatment of idiopathic trigeminal neuralgia (TN), although the results reported for each of these are diverse. OBJECTIVE: This study aimed to compare long-term pain control obtained by MVD, SRS, and RFR in patients with idiopathic TN. METHODS: To compare the results obtained by MVD, SRS, and RFR we chose a quasi-experimental, ambispective design with control groups but no pretest. A total of 52 participants (MVD n = 33, RFR n = 10, SRS n = 9) were included. Using standardized outcome measures, pain intensity, pain relief, quality of life, and satisfaction with treatment were assessed by an independent investigator. The TREND statement for reporting non-randomized evaluations was applied. Clinical outcomes were evaluated at the initial postoperative period and at 6 months, 1, 2, 3, 4, and 5 years postoperatively. RESULTS: MVD has shown better results in pain scales compared to ablative procedures. Significant differences between groups were found regarding pain intensity and pain relief at the initial postoperative period (p < 0.001) and 6 months (p = 0.022), 1 year (p < 0.001), 2 years (p = 0.002), and 3 years (p = 0.004) after the intervention. Those differences exceeded the thresholds of the minimal clinically important difference. A higher percentage of patients free of pain was observed in the group of patients treated by MVD, with significant differences at the initial postoperative period (p < 0.001) and 6 months (p = 0.02), 1 year (p = 0.001), and 2 years (p = 0.04) after the procedure. Also, a higher risk of pain recurrence was observed in the RFR and SRS groups (HR 3.15, 95% CI 1.33-7.46; p = 0.009; and HR 4.26, 95% CI 1.77-10.2; p = 0.001, respectively) compared to the MVD group. No significant differences were found in terms of quality of life and satisfaction with treatment. A higher incidence of complications was observed in the MVD group. CONCLUSION: Concerning pain control and risk of pain recurrence, MVD is superior to RFR and SRS, but not in terms of quality of life, satisfaction with treatment, and safety profile.

Hepatitis C screening and detection program in a large population: Epidemiological transition and characterization of the disease.

INTRODUCTION: Chronic hepatitis C (CHC) is considered an important public health challenge. Traditionally identified risk factors have undergone an epidemiological transition where other risk factors have become the main cause of new infections. OBJECTIVE: To describe risk factors associated to hepatitis C positivity through the evaluation of the epidemiological profile in hepatitis-C high-risk populations. METHODS: Cross-sectional study was conducted as part of an HCV screening program in Mexican population. All participants answered an HCV risk-factor questionnaire and took a rapid test (RT). All patients reactive to the test were subject to HCV PCR (polymerase chain reaction) confirmation. A logistic regression model was used to examine associations between HCV infection and risk factors. RESULTS: The study included 297 631 participants that completed a risk factor questionnaire and underwent an HCV rapid test (RT). In total, 12 840 (4.5%) were reactive to RT and 9257 (3.2% of participants) were confirmed as positives by PCR test. Of these, 72.9% had at least one risk factor and 10.8% were in prison. Most common risk factors were history of acupuncture/tattooing/piercing (21%), intravenous drug use (15%) and high-risk sexual practices (12%). Logistic regressions found that having at least one risk factor increased the probability of having an HCV-positive result by 20% (OR = 1.20, 95% CI: 1.15-1.26), compared to the population without risk factors. CONCLUSIONS: We identified 3.2% of HCV-viremic subjects, all associated with risk factors and older age. Screening and diagnosis of HCV in high-risk populations (including underserved populations) should be more efficient.

Glioblastoma Treatment: State-of-the-Art and Future Perspectives.

(1) Background: Glioblastoma is the most frequent and lethal primary tumor of the central nervous system. Through many years, research has brought various advances in glioblastoma treatment. At this time, glioblastoma management is based on maximal safe surgical resection, radiotherapy, and chemotherapy with temozolomide. Recently, bevacizumab has been added to the treatment arsenal for the recurrent scenario. Nevertheless, patients with glioblastoma still have a poor prognosis. Therefore, many efforts are being made in different clinical research areas to find a new alternative to improve overall survival, free-progression survival, and life quality in glioblastoma patients. (2) Methods: Our objective is to recap the actual state-of-the-art in glioblastoma treatment, resume the actual research and future perspectives on immunotherapy, as well as the new synthetic molecules and natural compounds that represent potential future therapies at preclinical stages. (3) Conclusions: Despite the great efforts in therapeutic research, glioblastoma management has suffered minimal changes, and the prognosis remains poor. Combined therapeutic strategies and delivery methods, including immunotherapy, synthetic molecules, natural compounds, and glioblastoma stem cell inhibition, may potentiate the standard of care therapy and represent the next step in glioblastoma management research.

Fractal anatomy of the hippocampal formation.

PURPOSE: We believed that the hippocampal complex is a fractal, and we try to demonstrate it. METHODS: We selected 12 magnetic resonance (MR) studies from healthy brains. Five women and 7 men without neurological or psychiatric disease were analyzed. The age range was 50-71 years old, with a mean 57.1 ± 7.6 years. Image series of MR were obtained through 3D SPGR in scanner GE Singa 3.0 T (general Electric, USA), matrix acquisition 512 Å-512 Å-120, field size 240 mm, voxel size 0.47 mm Å-0.47 mm Å-1.2 mm, repetition time of 13 ms and eco time of 5.6 ms. The MRI were imported in DICOM format in the OsiriXsoftware where they were contoured. Post processing was done with ImageJ software; Box Counting method for fractal analysis and we also used the Box Counting method of the BoneJ plugin. RESULTS: All of the hippocampus analyzed were a fractal. The fractal dimension analysis distribution of the measurements had a central tendency. The mean of hippocampal fractal dimension was 1.32635, the range was from 1.3373 to 1.5344. We found a short interval of variability in the hippocampal fractal number. CONCLUSIONS: The hippocampal complex is a fractal. The fractal analysis must be an objective measurement that can help us as a descriptive tool in hippocampal anatomy and maybe in a close future in the diagnosis of anatomical alterations.

Unmasking the Mimic: Radionecrotic Lesion Masquerading as Brain Neoplasia on Magnetic Resonance Imaging.

Corpus callosotomy is a therapeutic approach for drug-resistant epilepsy, with positive outcomes observed in managing atonic seizures. Despite a decline in its usage, radiosurgical callosotomy remains a viable option for drug-resistant epilepsy due to its low risks of post-radiation neoplasia, albeit not with exceptions. Brain radionecrosis is characterized by tissue death and vascular endothelial damage following the procedure. Despite the low risk of intracranial secondary malignancy associated with radiation in some cases, post-radiation lesions might present with distinct characteristics needing a thorough diagnostic approach. Herein, we present a unique case of a patient with focal epilepsy who developed a radionecrotic lesion following radiosurgical callosotomy, affecting the anterior cingulate cortex, and mimicking a central nervous system (CNS) tumor. Molecular imaging techniques, including 18-fluorodeoxyglucose positron emission tomography/computed tomography (18-FDG PET/CT) and 11C-acetate PET/CT scans, were employed to differentiate the lesion from a tumor. This case underscores the importance of considering radionecrosis as a differential diagnosis in patients who undergo radiosurgical callosotomy presenting with ring-like enhancement lesions on magnetic resonance imaging (MRI).

Radiation therapy for optic nerve sheath meningiomas: Local control and treatment related visual changes.

Objective: Our primary objective is to evaluate the local control of optic nerve sheath meningiomas (ONSMs) treated with ionizing radiation and related visual changes after treatment. Our secondary objective is to describe the clinical characteristics and perform an analysis of the treatment impact on the functional status of this group of patients. Methods: We present our series of 19 patients treated with ionizing radiation therapy at our radio-neurosurgery unit between 2016 and 2022. The setting, ophthalmological follow-up, morbidity, and survival are analyzed and discussed. Results: Patients were followed up, and the impact of treatment on local disease control, visual alterations of the affected eye, and functional status of the patient were analyzed. The progression-free survival (PFS) median was 60 months (95% CI 50.3-69.6 months). The estimated PFS rates at 48 and 66 months were 100% and 66%, respectively. At diagnosis, nine (47.3%) eyes were in amaurosis and ten (52.6%) with vision. Of the ten patients without amaurosis at the time of diagnosis, three (30%) maintained unchanged visual acuity, and seven (70%) had decreased visual acuity; three of them developed amaurosis during the first year after treatment (p = 0.018). Conclusions: Using ionizing radiation therapy is a successful treatment for the local control of ONSMs. This therapeutic modality can compromise the visual acuity of the affected eye and improve dyschromatopsia and campimetry defects. The life prognosis is good for these patients, with a zero mortality rate, but their vision prognosis is poor.

Diagnostic Algorithm for Intracranial Lesions in the Emergency Department: Effectiveness of the Relative Brain Volume and Hounsfield Unit Value Measured by Perfusion Tomography.

Background Early treatment of intracranial lesions in the emergency department is crucial, but it can be challenging to differentiate between them. This differentiation is essential because the treatment of each type of lesion is different. Cerebral computed tomography perfusion (CTP) imaging can help visualize the vascularity of brain lesions and provide absolute quantification of physiological parameters. Compared to magnetic resonance imaging, CTP has several advantages, such as simplicity, wide availability, and reproducibility. Purpose This study aimed to assess the effectiveness of Hounsfield units (HU) in measuring the density of hypercellular lesions and the ability of CTP to quantify hemodynamics in distinguishing intracranial space-occupying lesions. Methods A retrospective study was conducted from March 2016 to March 2022. All patients underwent CTP and CT scans, and relative cerebral blood volume (rCBV) and HU were obtained for intracranial lesions. Results We included a total of 244 patients in our study. This group consisted of 87 (35.7%) individuals with glioblastomas (GBs), 48 (19.7%) with primary central nervous system lymphoma (PCNSL), 45 (18.4%) with metastases (METs), and 64 (26.2) with abscesses. Our study showed that the HUs for METs were higher than those for GB (S 57.4% and E 88.5%). In addition, rCBV values for PCNSL and abscesses were lower than those for GB and METs. The HU in PCNSL was higher than those in abscesses (S 94.1% and E 96.6%). Conclusion PCT parameters provide valuable information for diagnosing brain lesions. A comprehensive assessment improves accuracy. Combining rCBV and HU enhances diagnostic accuracy, making it a valuable tool for distinguishing between lesions. PCT's widespread availability allows for the use of both anatomical and functional information with high spatial resolution for diagnosing and managing brain tumor patients.

Relative cerebral blood volume as response predictor in the treatment of recurrent glioblastoma with anti-angiogenic therapy.

BACKGROUND: Glioblastoma is one of the most common brain tumors in adult populations, usually carrying a poor prognosis. While several studies have researched the impact of anti-angiogenic therapies, especially anti-VEFG treatments in glioblastoma, few have attempted to assess its progress using imaging studies. PURPOSE: We attempted to analyze whether relative cerebral blood volume (rCBV) from dynamic susceptibility-weighted contrast-enhanced MRI (DSC-MRI) could predict response in patients with glioblastoma undergoing Bevacizumab (BVZ) treatment. METHODS: We performed a retrospective study evaluating patients with recurrent glioblastoma receiving anti-angiogenic therapy with BVZ between 2012 and 2017 in our institution. Patients were scheduled for routine MRIs at baseline and first-month follow-up visits. Studies were processed for DSC-MRI, cT1, and FLAIR images, from which relative cerebral blood volume measurements were obtained. We assessed patient response using the Response Assessment in Neuro-Oncology (RANO) working group criteria and overall survival. RESULTS: 40 patients were included in the study and were classified as Bevacizumab responders and non-responders. The average rCBV before treatment was 4.5 for both groups, and average rCBV was 2.5 for responders and 5.4 for non-responders. ROC curve set a cutoff point of 3.7 for rCBV predictive of response to BVZ. Cox Multivariate analysis only showed rCBV as a predictive factor of OS. CONCLUSION: A statistically significant difference was found in rCBV between patients who responded and those who did not respond to BVZ treatment. rCBV may be a low-cost and effective marker to assess response to Bevacizumab treatment in GBM.

Assessing the Malignancy Risk of a Meningioma by Its Location.

BACKGROUND: Meningiomas represent 30% of primary intracranial tumors. The current incidence is up to 4.5 cases per 100,000 habitants worldwide. Although there is no prognostic difference among benign histopathological subtypes, atypical meningiomas and malignant meningiomas (WHO grade II and III respectively) may extend to the adjacent brain parenchyma, dura mater, and osseous tissue with a recurrence score (21-49%). This manuscript analyzes the malignancy risk according to neoplastic localization through a logistic retrospective analysis from a total sample of 452 patients with grade I, II, and III (WHO) meningiomas. METHODS: Detailed data collection through a three-year retrospective analysis (January 2008 to December 2011) was applied at Mexico's National Neurology and Neurosurgery Institute including patients with intracranial or spinal-cord meningioma, preoperative imaging study availability and post-surgical histopathological diagnosis. Formal written consent was not required with a waiver by the appropriate national research ethics committee in accordance with the provisions of the regulations of the general health law of Mexico. RESULTS: Convexity lesions displayed an increased risk of malignancy turning for non-benign meningiomas with an odds ratio of 3.1 (95% CI 1.6 to 5.7, p=0.0002) meanwhile skull-base meningiomas present an inverse risk with an odds ratio of 0.4 (95% CI 0.2 to 0.9, p=0.02), as well as spinal-cord meningiomas with an odds ratio of 0.3 (95% CI 0.1 to 0.9). CONCLUSION: Skull base and spinal cord meningiomas usually have benign behavior, meanwhile grade II or III meningiomas within this location are rare. The present work provides an additional criterion for decision making, according to the meningioma's location.

Endoscopic Third Ventriculostomy for Obstructive Hydrocephalus Secondary to Delayed Intracerebellar Hematoma.

Nowadays, endoscopic third ventriculostomy (ETV) in neurosurgery has yielded good clinical results in various conditions. Intraventricular endoscopic procedures can be performed in different pathologies and not only in non-communicating hydrocephalus. This is presented accordingly in this clinical case. We present the case of a patient who suffered a blunt traumatic brain injury (TBI) in the occipital region. Upon his arrival at the medical facility, he displayed altered neurological status and showed symptoms of aggressiveness, slurred speech, and gait ataxia. Initial non-contrast brain computed tomography scan presented a cerebellar traumatic subacute hematoma and secondary hydrocephalus. Therefore, we performed an ETV. In most reported cases of cerebellar contusions among patients with TBI, the treatment was suboccipital craniectomy, clot evacuation, and external ventricular drainage (EVD). Unlike this case, the determined procedure was minimally invasive through ETV for the resolution of hydrocephalus with good clinical outcomes in addition to low morbidity and mortality. This case shows in the setting of delayed intracerebellar traumatic hematoma with secondary hydrocephalus being the main cause of neurological deterioration, a minimally invasive treatment such as ETV is suitable.

The Thalamic Arteriovenous Malformations Have Better Prognosis than Basal Ganglia Malformations Regarding Obliteration: Prognostic Factors Analysis.

BACKGROUND: Arteriovenous malformations (AVMs) are rare vascular congenital lesions that affect mainly patients during their productive years of life. In order to obtain a better quality of life for patients with this disease, a multidisciplinary approach is recommended. Radiosurgery is one of the treatment modalities available for AVMs, but many factors may influence the effectiveness of this strategy. Classically, it has been said that deep-seated lesions have a particular behavior compared with AVMs in other regions, but a differentiation between thalamic lesions and those located in the basal ganglia has not been made. METHODS: Institutional records for central core AVMs treated with radiosurgery between January 2004 and January 2014 were retrospectively analyzed. Brainstem lesions were excluded from the analysis. RESULTS: Forty-nine patients with deep-seated AVMs were included. Forty-three (87.8%) were located in the thalamus and 6 (12.2%) in the area of basal ganglia. The nidus mean volume was 4.1 cm3 (SD: 4.1), the maximum diameter mean was of 19.5 mm (SD: 8.0). The prescription dose was 18.2 Gy (SD: 2.1), and the follow-up time was 75.8 months (SD: 32.5). There was a greater obliteration rate in thalamic AVMs compared with those located in the basal ganglia: 81.4% versus 33.3% (P = 0.026), respectively. There was no association between categorical variables and obliteration rate. CONCLUSIONS: Stereotactic radiosurgery is a good option for patients with thalamic and basal ganglia AVMs, but a multidisciplinary approach to decision-making is mandatory in order to achieve the best results.

Frameless radiosurgical third ventriculostomy: Technical report.

BACKGROUND: We describe the technical report and results of the first image-guided, linear accelerator, frameless radiosurgical third ventriculostomy. METHODS: We report a 20 years old man, with diplopia, balance disturbances, and limitation for gaze supraversion. Magnetic resonance imaging resonance imaging of the brain and cranial computed tomography showed showed a left thalamic-midbrain lesion that caused partial compression of the Silvio aqueduct and mild ventricular dilatation. The biopsy revealed the diagnosis of pleomorphic xanthoastrocytoma. Before radical treatment of the tumor with fractionated stereotactic radiotherapy, the patient underwent to frameless radiosurgical third ventriculostomy, on the TrueBeam STX® platform with the ExacTrac localization system. The target used was the one defined on the floor of the third ventricle, at the midpoint between the mammillary bodies and the infundibular recess. The prescription dose was 120 Gy, given using a monoisocentric technique of multiple noncoplanar circular arches. The geometric arrangement of the plan consisted of 15 arches, with a 4 mm cone, distributed over a 110° table. RESULTS: There was symptomatic and image improvement two days after radiosurgery. On CT, a reduction in ventricular dilation was observed with a reduction in the Evans index from 0.39 (initial CT) to 0.29 (CT at 15 days). In 3.0T magnetic resonance image at 3 months, we showed the third ventriculostomy. There have been no treatment failures or complications. CONCLUSION: It is possible to effectively perform the frameless radiosurgical third ventriculostomy without associated morbidity in the short term.

Linear Accelerator-Based Radiosurgery of Grade I Intracranial Meningiomas.

OBJECTIVE: To determine the local control rate and complication rate in the treatment of grade I intracranial meningiomas. METHODS: A retrospective study was performed of patients with grade I meningioma who received radiosurgery with a dedicated linear accelerator from January 2002 to August 2012 with a minimum follow-up of 2 years. We performed descriptive statistics, logistic regression, and progression-free survival analysis through a Kaplan-Meier curve. RESULTS: Seventy-five patients with 78 grade I meningiomas received radiosurgery, 39 underwent surgery plus adjuvant radiosurgery, and 36 only radiosurgery. The follow-up median time was 68 months (range, 35-120 months). The tumor control rate was 93%, the 5-year progression-free survival was 92% (95% confidence interval, 77%-98%). Acute toxicity was 2.6%, and grade 1-2 late toxicity was 26.6%. Postradiosurgery edema was the main late morbidity. Age >55 years was the only significant factor for attaining a response >75%. The background of surgery before radiosurgery was the only significant prognostic factor for showing edema (odds ratio 5.78 [95% confidence interval, 2.14-15.64]). CONCLUSIONS: The local control rate attained in our series is similar to that reported in other series worldwide; the acute toxicity rate was low and late toxicity was moderate.

Retroclival and spinal subdural hematoma after traumatic brain injury - A case report and literature review.

BACKGROUND: Retroclival hematomas are rare and occur mostly in the pediatric population. They are variously attributed to trauma, apoplexy, and vascular lesions. With motor vehicle accidents (MVAs), the mechanism of traumatic injury is forced flexion and extension. There may also be associated cervical spinal and/or clivus fractures warranting fusion. CASE DESCRIPTION: A 35-year-old male sustained a traumatic brain injury after a fall of 5 m at work. His Glasgow coma scale (GCS) on admission was 13 (M6V3O4). He had no cranial nerve deficits. The brain computed tomography (CT) showed a retroclival subdural hematoma that extended to the C2 level. CONCLUSIONS: Most retroclival hematomas are attributed to MVAs, and cranial CT and magnetic resonance studies typically demonstrate a combination of posterior fossa hemorrhage with retroclival hematomas (intra or extradural). Patients with retroclival hematomas but high GCS scores on admission usually have better prognoses following traumatic brain injuries attributed to MVA. Notable however is the frequent association with additional cervical and/or craniocervical injuries (e.g. such as odontoid fracture) that may warrant surgery/fusión.

Posterior bi-parietal decompressive craniectomy in refractory intracranial hypertension secondary to civilian gunshot wound. Case report and review of literature.

BACKGROUND: Decompressive craniectomy is recommended as second tier therapy for unresponsive intracranial hypertension in Traumatic Brain Injury. There have been reports of a Bi-Occipital craniectomy in cases where the focal injury is posterior. CASE DESCRIPTION: The work has been reported in line with the SCARE criteria. There is a 56-year-old male with Traumatic brain injury secondary to gunshot and intracranial hypertension, managed with biparietal craniectomy, after place a intracranial pressure monitor, whit good response to surgical and medical treatment, even with good outcome after hospitalization. CONCLUSIONS: In selected cases a posterior bi-parietal craniectomy can be performed in a safe way with acceptable results to treat refractory Intracranial hypertension. We propose that this neurosurgical technique can be used in patients with posterior focal injuries.

Intracranial arteriovenous malformations treated with LINAC-based conformal radiosurgery: validation of the radiosurgery-based arteriovenous malformation score as a predictor of outcome.

OBJECTIVE: To validate the radiosurgery-based arteriovenous malformation score (RBAS) as a predictor of outcome in patients with arteriovenous malformations (AVMs) treated with LINAC-based conformal radiosurgery. METHODS: We analysed 40 patients with a mean follow-up of 22 months. One patient (2.5%) pertained to Spetzler-Martin Grade I, 11 (27.5%) to Grade II, 19 (47.5%) to Grade III, eight (20%) to Grade IV and one (2.5%) to grade V. The mean RBAS was 2.0 (range: 0.76-5.56). The mean obliteration prediction index (OPI) and the Karlsson index (KI) were 0.74 (range: 0.2-2.86) and 109.48 (range: 3.0-350.7) respectively. Outcomes were analysed according to the OPI, KI and RBAS. RESULTS: We analysed different cutoff points in the RBAS and found a significant difference to predict the outcome in four scores: 1.2, 1.6, 1.7 and 1.8. In the group with RBAS < or = 1.8, 13 (68%) had an excellent outcome and six (33%) did not, while with RBAS>1.8, seven (32%) had an excellent outcome and 14 (67%) did not (p = 0.02). We did not find any correlation between Spetzler-Martin grading scale or OPI and outcome (p = 0.7 and p = 0.3 respectively). The KI predicted the excellent outcome in 8/9 patients (89%) with KI < or = 27 and in 12/31 patients (39%) with KI>27 (p = 0.08). CONCLUSION: The RBAS seems to be a good predictor of outcome in patients with AVMs treated with LINAC-based conformal radiosurgery as in patients treated with Gamma Knife. It remains only to find the best cutoff point based on a larger series and longer follow-up.

Brain hemorrhage after electrical burn injury: Case report and probable mechanism.

BACKGROUND: High-voltage electric injury may induce lesion in different organs. In addition to the local tissue damage, electrical injuries may lead to neurological deficits, musculoskeletal damage, and cardiovascular injury. Severe vascular damage may occur making the blood vessels involved prone to thrombosis and spontaneous rupture. CASE DESCRIPTION: Here, we present the case of a 39-year-old male who suffered an electrical burn with high tension wire causing intracranial bleeding. He presented with an electrical burn in the parietal area (entry zone) and the left forearm (exit zone). The head tomography scan revealed an intraparenchimatous bleeding in the left parietal area. In this case, the electric way was the scalp, cranial bone, blood vessels and brain, upper limb muscle, and skin. The damage was different according to the dielectric property in each tissue. The injury was in the scalp, cerebral blood vessel, skeletal muscle, and upper limb skin. The main damage was in brain's blood vessels because of the dielectric and geometric features that lead to bleeding, high temperature, and gas delivering. CONCLUSION: This is a report of a patient with an electric brain injury that can be useful to elucidate the behavior of the high voltage electrical current flow into the nervous system.

Radiosurgical third ventriculostomy: Technical note.

BACKGROUND: We describe a minimally invasive technique to perform a radiosurgical third ventriculostomy in a patient with mild obstructive hydrocephalus secondary to malignant pathology. METHODS: A 42 years old woman with diagnosis of clear cells renal carcinoma and with right nefrectomy performed last year. Cranial Magnetic Resonance Imaging showed two brain metastasis: one right temporal, and other in the pons with Sylvian aqueduct partial obliteration and mild ventricular enlargement. The patient received radiosurgical treatment for brain metastasis; after this procedure a new target was defined on the floor of the third ventricle, in the midpoint between the mamillary bodies and the infundibular recess where we delivered 100 Gy delivered by an isocentric multiple noncoplanar arcs technique, with a 6 MV Novalis(®) dedicated LINAC. A series of 21 arcs was arranged with a radiation field generated by a 4 mm circular collimator. RESULTS: One week pos-irradiation in the head CT we did not find significant changes in the metastatic lesions; however the VSI diminished 4%, despite of persistent aqueduct obliteration. At three months we perform 3.0 T MRI where we confirmed the presence of the third ventriculostomy (2.63 mm diameter). CONCLUSION: This report demonstrates, for the first time, the ability of a dedicated LINAC to perform a precise third ventriculostomy without associate morbility in short term.

Influence of ceramic surface conditioning and resin cements on microtensile bond strength to a glass ceramic.

STATEMENT OF PROBLEM: It is not clear how different glass ceramic surface pretreatments influence the bonding capacity of various luting agents to these surfaces. PURPOSE: The purpose of this study was to evaluate the microtensile bond strength (microTBS) of 3 resin cements to a lithia disilicate-based ceramic submitted to 2 surface conditioning treatments. MATERIAL AND METHODS: Eighteen 5 x 6 x 8-mm ceramic (IPS Empress 2) blocks were fabricated according to manufacturer's instructions and duplicated in composite resin (Tetric Ceram). Ceramic blocks were polished and divided into 2 groups (n=9/treatment): no conditioning (no-conditioning/control), or 5% hydrofluoric acid etching for 20 seconds and silanization for 1 minute (HF + SIL). Ceramic blocks were cemented to the composite resin blocks with 1 self-adhesive universal resin cement (RelyX Unicem) or 1 of 2 resin-based luting agents (Multilink or Panavia F), according to the manufacturer's instructions. The composite resin-ceramic blocks were stored in humidity at 37 degrees C for 7 days and serially sectioned to produce 25 beam specimens per group with a 1.0-mm(2) cross-sectional area. Specimens were thermal cycled (5000 cycles, 5 degrees C-55 degrees C) and tested in tension at 1 mm/min. Microtensile bond strength data (MPa) were analyzed by 2-way analysis of variance and Tukey multiple comparisons tests (alpha=.05). Fractured specimens were examined with a stereomicroscope (x40) and classified as adhesive, mixed, or cohesive. RESULTS: The surface conditioning factor was significant (HF+SIL > no-conditioning) (P<.0001). Considering the unconditioned groups, the microTBS of RelyX Unicem was significantly higher (9.6 +/- 1.9) than that of Multilink (6.2 +/- 1.2) and Panavia F (7.4 +/- 1.9). Previous etching and silanization yielded statistically higher microTBS values for RelyX Unicem (18.8 +/- 3.5) and Multilink (17.4 +/- 3.0) when compared to Panavia F (15.7 +/- 3.8). Spontaneous debonding after thermal cycling was detected when luting agents were applied to untreated ceramic surfaces. CONCLUSION: Etching and silanization treatments appear to be crucial for resin bonding to a lithia disilicate-based ceramic, regardless of the resin cement used.