Subcompartmentalization of extracellular extravascular space (EES) into permeability and leaky space with local arterial input function (AIF) results in improved discrimination between high- and low-grade glioma using dynamic contrast-enhanced (DCE) MRI.

PURPOSE: To modify the generalized tracer kinetic model (GTKM) by introducing an additional tissue uptake leakage compartment in extracellular extravascular space (LTKM). In addition, an implicit determination of voxel-wise local arterial input function (AIF) Cp (t) was performed to see whether these changes help in better discrimination between low- and high-grade glioma using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). MATERIALS AND METHODS: The modified model (LTKM) was explored and fitted to the concentration-time curve C(t) of each voxel, in which the local AIF Cp (t) could be estimated by a time invariant convolution approximation based on a separately measured global AIF Ca (t). A comparative study of tracer kinetic analysis was performed on 184 glioma patients using DCE-MRI data on 1.5T and 3T MRI systems. RESULTS: The LTKM analysis provided more accurate pharmacokinetic parameters as evidenced by their relative constancy with respect to the length of concentration-time curve used. In addition, LTKM with local AIF resulted in improved discrimination between low-grade and high-grade gliomas. CONCLUSION: LTKM with local AIF provides more accurate estimation of physiological parameters and improves discrimination between low-grade and high-grade gliomas as compared with GTKM.

Correlation of DTI metrics in the wall and cavity of brain abscess with histology and immunohistochemistry.

Diffusion tensor imaging (DTI) was performed in eight patients with brain abscess (BA). The aim of this study was to see the difference in the relationship between intercellular cell adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) expression and DTI metrics measured in vivo in the wall and cavity of BA and its possible explanation vis-à-vis histology and immunohistochemistry. Neuroinflammatory molecules (NMs) were quantified from BA cavity aspirate of the patients and quantitative immunohistochemical analysis was performed for ICAM-1 and LFA-1 in the BA wall, showing maximal positive staining and correlated with DTI metrics. The fractional anisotropy (FA) significantly increased while mean diffusivity and spherical anisotropy significantly decreased in the BA wall compared to the BA cavity. In the BA wall, FA and linear anisotropy (CL) showed a significant positive correlation with ICAM-1 and LFA-1 expression whereas FA and planar anisotropy positively correlated with NMs quantified from aspirated pus respectively. Higher FA values in the BA wall compared to BA cavity, even when ICAM-1 and LFA-1 were expressed only in the macrophages and not in the collagen fibers, suggests that a combination of both concentric layers of collagen fibers as well as neutrophils and macrophages provide structural orientation and are responsible for increased FA. In the BA wall, increased CL was found compared to the cavity, indicating the presence of concentrically laid collagen fibers responsible for the diffusion of water molecules in the direction parallel to the collagen fibers. We conclude that in the BA, different mechanisms are operative for the changes in the DTI metrics in the wall and cavity; these conclusions are validated by histology and immunohistochemistry.

Serial changes in diffusion tensor imaging metrics of corpus callosum in moderate traumatic brain injury patients and their correlation with neuropsychometric tests: a 2-year follow-up study.

OBJECTIVE: To assess longitudinally the severity of diffuse axonal injury in the corpus callosum in patients with moderate traumatic brain injury (TBI) through quantitative diffusion tensor imaging and to correlate these changes with neuropsychometric tests (NPT) at 6 and 24 months after injury. DESIGN: Prospective longitudinal study. PARTICIPANTS: Sixteen patients with TBI and 17 age/sex-matched healthy controls. METHODS: Patients underwent magnetic resonance imaging at 3 time points: within 2 weeks (range = 5-14 days), 6 months, and 24 months after injury. NPT could be performed only at 6 and 24 months. RESULTS: In patients with TBI, a significant increase in fractional anisotropy (FA) values in genu as well as an insignificant decrease in radial diffusivity (RD) and mean diffusivity values in genu and splenium were observed over time, respectively. FA, RD, and mean diffusivity values continued to be abnormal in patients compared with controls at the end of 2 years. Although some NPT scores improved over time in these patients, these were still significantly impaired compared with controls. CONCLUSIONS: FA and RD indices appear to be surrogate markers of microstructural alterations in patients over time and correlate significantly with some of the NPT scores. The recovery in these indices associated with recovery in neurocognitive deficits suggests that these indices may be used as an objective marker for residual injury in these patients.

Tumor irrigation fluid enhances diagnostic efficacy in endoscopic biopsies of intracranial space-occupying lesions.

PURPOSE: Intraventricular neuroendoscopic CNS biopsiesare small, fragmented, and tissue is frequently inadequate for diagnosis. We have attempted to increase cellular yield using tumor irrigation fluid (TIF) and a cyto-histological approach for diagnosis of intracranial tumors, cysts, and infections. METHODS: A retrospective group of 147 cases, where only endoscopic biopsies were obtained, was compared with a prospective group of 31 cases where along with the endoscopic biopsies, tumor irrigation fluid (TIF) was collected. Tumor cyst fluid was obtained from cystic tumors (n=6). Small tumor fragments in the TIF were utilized to make squash smears (n=31). Clotted fragments were processed for sections in (n=3). Centrifuged deposit smears were prepared from tumor irrigation fluid and tumor cyst fluid. RESULTS: Conclusive pathological diagnosis in endoscopic biopsies could be arrived at in 77.4% (24/31) prospective cases and 80.3% (118/147) in retrospective cases. Collection of TIF with a cyto-histological diagnostic approach gave a significantly higher rate of conclusive pathological diagnosis in 93.5% (29/31) cases in the prospective group. CONCLUSIONS: Additional tissue from TIF preserves the original biopsy, provides more material for diagnosis and gives a better morphological picture in smears. Hence diagnosis of endoscopic CNS biopsies can be rendered in more cases and with greater degree of confidence.

Central pontine myelinolysis in a pediatric head injury patient.

Central pontine myelinolysis occurs inconsistently as a complication of severe and prolonged hyponatremia, particularly when corrected too rapidly. It is a concentrated, frequently symmetric, noninflammatory demyelination within the central basis pontis. We describe a head injury patient who suffered this clinical entity as a consequence of rapidly corrected hyponatremia. Clinical manifestation and radiological findings are described along with a review of the pertinent literature.

Intraoperative ventriculo-stomographic evaluation of endoscopic cerebrospinal fluid diversion and flow restoration procedures.

PURPOSE: This prospective study was designed for intra-operative demonstration of cerebrospinal fluid (CSF) flow in ventricles and cisternal spaces before and after neuroendoscopic procedure. The aim of this study was to evaluate site of obstruction of CSF flow and subsequent stomal or aqueductal patency after endoscopic third ventriculostomy (ETV) or aqueductoplasty in patients with hydrocephalus of diverse aetiology. METHOD: Seventeen patients with hydrocephalus due to diverse aetiology underwent ETV (n = 15) and aqueductoplasty (n = 2) or cysto-ventrticulostomy (n = 1) or transaqueductal removal of neurocysticercus cyst (NCC) (n = 1). Intra-operatively, radio-opaque contrast agent (iohexol) instillation into the third ventricle was used for qualitative evaluation of obstruction and post-procedure CSF flow across the stoma into cisternal spaces. RESULT: 11 male and 6 female patients ranging from 3 to 50 years of age were included in the study. Post-procedure intra-operative ventriculo-stomography (IOVSG) showed free flow of dye across the endoscopic stoma (n = 13) or aqueduct (n = 2) into cisternal spaces. Diagnosis of fourth ventricular NCC was made in one patient with panventriculomegaly. In two patients of tuberculous meningitis hydrocephalus, poor flow of contrast in the prepontine area and basal cisterns was seen on IOVSG. They were subjected to ventriculoperitoneal shunt insertion in the same sitting. Cine MRI confirmed the patency of stoma or aqueduct in follow-up period in all patients with successful endoscopic procedure. CONCLUSION: IOVSG is a simple and safe technique that helps in confirming the adequacy of endoscopic procedure during surgery and thereby facilitates intra-operative decision about further management.

Craniotomy with Ridges: A Time and Cost-Efficient Technique for Unwavering Fixation of Bone Flap.

After advent of the power driven tools, the ease of surgeons and pace of surgery has been enhanced. Nowadays, most of the neurosurgeons are tend to use the motorized drills for elevating a bone flap to make a craniotomy. The bone cutting by the craniotome is wide and nonbeveled, which mandates the fixation of bone flap at closure, either by wiring, miniplates, or other fixation techniques. This not only lengthens the duration of surgery but also adds extra cost of miniplates to the patient. Here we are presenting a novel technique of elevating a bone flap where fixation at the end of surgery is not obligatory, without any risk of sinking of bone flap into the craniotomy defect.

Role of diffusion tensor imaging metrics and in vivo proton magnetic resonance spectroscopy in the differential diagnosis of cystic intracranial mass lesions.

The purpose of this study was to determine whether proton magnetic resonance spectroscopy (PMRS) and diffusion tensor imaging (DTI) indices, fractional anisotropy (FA) and mean diffusivity (MD) can be used to distinguish brain abscess from cystic brain tumors, which are difficult to distinguish by conventional magnetic resonance imaging (MRI). Fifty-three patients with intracranial cystic mass lesions and 10 normal controls were studied. Conventional MRI, PMRS and DTI of all the patients were performed on a 1.5-T GE scanner. Forty patients were with brain abscess and 13 with cystic tumors. Cytosolic amino acids (AAs) were present in 32 of 40 brain abscess patients. Out of 13 patients with cystic tumors, lactate and choline were seen in 3 and only lactate was present in 10 patients on PMRS. All 40 cases of abscess had high FA, while all 13 cases of tumor cysts had high MD values. We conclude that FA measurements are more sensitive in predicting the abscess, while PMRS and MD are more specific in differentiating abscess from cystic tumors. We suggest that PMRS should be combined with DTI rather than with diffusion-weighted imaging as FA can be used as an additional parameter for separation of abscess from other cystic intracranial mass lesions.

Combined trans-sphenoidal and simultaneous trans-ventricular-endoscopic decompression of a giant pituitary adenoma: case report.

OBJECTIVE: This is the first report of the simultaneous combined use of trans-sphenoidal and trans-ventricular-endoscopic route for decompression of a giant pituitary adenoma. METHOD: A 38 year old man presented to us with symptoms of raised intracranial pressure along with visual and hypothalamic disturbances. The CT scan revealed destruction of the sella by a large (5 x 3.5 x 2.5 cm) well defined enhancing mass in the sella and suprasellar region extending laterally up to the cavernous sinuses and both carotid arteries and superiorly into the lumen of the 3rd ventricle producing obstructive hydrocephalus. On T2WI of the non-contrast MRI scan the mass was iso-intense to grey matter suggesting the possibility of a firm nature of the adenoma. The tumour was first approached by the standard trans-sphenoidal route and as predicted from the pre-operative MRI, the tumour was found to be firm and not amenable to suction. After decompression of the intra-sellar part of the tumour, the intracranial pressure was raised in an attempt to make the remainder of the tumour descend into the sella but without success. The suprasellar part of the tumour was then simultaneously addressed via a trans-ventricular-endoscopic route but the firm tumour did not yield to endoscopic instruments viz. biopsy forceps, angiographic catheter and electrosurgical probes. It was then gently pushed down towards the sella and decompressed piecemeal by using trans-sphenoidal instruments. The sellar cavity was reconstructed using fat, fascia lata graft and a piece of septal bone. RESULTS: Post-operatively, the patient showed a remarkable improvement of his symptoms of raised intracranial pressure, hypothalamic dysfunction and visual disturbances. Follow-up imaging at 2 months and 1 year, did not show any residual or recurrent tumour. CONCLUSIONS: This novel technique of the combined trans-sphenoidal and simultaneous trans-ventricular-endoscopic approach is a viable option for patients with giant fibrous pituitary adenoma when the tumour is not yielding to the trans-sphenoidal route alone.

Comparative evaluation of corpus callosum DTI metrics in acute mild and moderate traumatic brain injury: its correlation with neuropsychometric tests.

PRIMARY OBJECTIVE: To look for differences in vulnerability of corpus callosum (CC) in patients of mild and moderate traumatic brain injury (TBI) in the acute stage using quantitative diffusion tensor imaging (DTI) and to correlate these with neuropsychometric tests (NPT) done at 6 months post-injury. RESEARCH DESIGN, METHODS AND PROCEDURES: Conventional MRI, DTI and NPT were performed on 83 patients (moderate TBI, n = 57; mild TBI, n = 26) within 5-14 days after TBI. Thirty-three age- and sex-matched healthy controls were also included for comparison. RESULTS: Significantly decreased fractional anisotropy (FA) in genu and splenium; significantly increased radial diffusivity (RD) values in genu, midbody and splenium with significant increase in mean diffusivity (MD) and a decrease in axial diffusivity (AD) only in genu, respectively, in patients with moderate TBI compared to healthy controls were observed. However, in moderate TBI, significantly decreased FA was found only in genu compared to mild TBI. Moderate TBI showed poor NPT scores compared to mild TBI, but this did not reach statistical significance. CONCLUSIONS: It is concluded that DTI abnormalities in the regions of CC were more in patients with moderate TBI compared to mild TBI and this was associated with relatively poor neuropsychological outcome 6 months post-injury.

Endoscopic diagnosis of a pineal papillary glioneuronal tumor with extensive ventricular involvement: case report with review of literature.

Papillary glioneuronal tumor (PGNT) is a newly described mixed glioneuronal tumor, recently included in the World Health Organization classification of central nervous system tumors. We report morphologic and immunohistochemical characteristics PGNT of the pineal region extending into the third and lateral ventricles in a four-year-old male child and reviewed all the cases reported in the international literature till date. In this child the diagnosis of PGNT was established by endoscopic biopsy and squash smear examination.

Endoscopic Management of Intraventricular Neurocysticercosis.

AIM: To evaluate the technique and outcome of endoscopic management of intraventricular neurocysticercosis (NCC). MATERIAL AND METHODS: We retrospectively analysed the records of 30 consecutive patients of intraventricular (intra-third and fourth ventricle) NCC who underwent endoscopic management. The clinical profiles of the patients were evaluated which included age, symptoms and signs. Transcranial endoscopy was performed through a frontal burr hole using a Gaab Universal Endoscope system with rigid 0° and 30° telescope for endoscopic third ventriculostomy and removal of the cyst was described. The mean follow-up period was 22.6 months. RESULTS: In 86.67% (26/30) patients we are able to visualize/excise/decompress the cyst. We were able to successfully excise all the third ventricular cysts (16/16) and in 66.67% (8/12) of the fourth ventricular cysts. In 90% (27/30) patients we were able to successfully divert the CSF flow and achieve long-term shunt free period. CONCLUSION: We found that endoscopic cerebrospinal fluid (CSF) diversion in cases of intraventricular NCC is feasible and associated with high success rate. Endoscopic CSF diversion in NCC related hydrocephalus usually produces a long-term cure.

Retrograde Wallerian degeneration of cranial corticospinal tracts in cervical spinal cord injury patients using diffusion tensor imaging.

Diffusion tensor imaging (DTI) has the potential to reveal disruption of white matter microstructure in chronically injured spinal cords. We quantified fractional anisotropy (FA) and mean diffusivity (MD) to demonstrate retrograde Wallerian degeneration (WD) of cranial corticospinal tract (CST) in cervical spinal cord injury (SCI). Twenty-two patients with complete cervical SCI in the chronic stage were studied with DTI along with 13 healthy controls. Mean FA and MD values were computed for midbrain, pons, medulla, posterior limb of internal capsule, and corona radiata. Significant reduction in the mean FA and increase in MD was observed in the cranial CST in patients with SCI compared with controls, suggesting retrograde WD. Statistically significant inverse FA and MD changes were noted in corona radiata, indicating some restoration of spared white matter tracts. Temporal changes in the DTI metrics suggest progressing degeneration in different regions of CST. These spatiotemporal changes in DTI metrics suggest continued WD in injured fibers along with simultaneous reorganization of spared white matter fibers, which may contribute to changing neurological status in chronic SCI patients.

Lymphocyte transformation test: a new method for diagnosis of neurocysticercosis.

Neurocysticercosis (NCC) is the commonest parasitic disease of the central nervous system. Neuroimaging tools are considered gold standard for the diagnosis of NCC, but its availability is restricted in developing countries. So, there is a definite need for reliable immunodiagnostic tool. The aim of the present study was to evaluate cyst fluid antigen-based lymphocyte transformation test (LTT) as a diagnostic tool for NCC. Tissue culture plates (96 wells) were coated with cyst fluid having protein concentration of 20 mug/well. Freshly isolated lymphocytes from 48 symptomatic NCC cases, 39 matched disease controls, and 40 healthy volunteers were seeded at a concentration of 1 x 10(6) cells/well. LTT was performed as per standard guidelines and (3)H-thymidine was used to measure cell proliferation. The cutoff stimulation index (SI) was defined as mean of controls +2 SD. The mean SI of the cell proliferation for NCC cases was significantly higher than controls (5.83 versus 1.29, P < 0.001). The sensitivity and specificity of LTT for diagnosis of NCC were 93.8% and 96.2%, respectively. The study shows that LTT can be used as an immunodiagnostic tool for NCC; however, it needs to be validated in other endemic areas.

DTI derived indices correlate with immunohistochemistry obtained matrix metalloproteinase (MMP-9) expression in cellular fraction of brain tuberculoma.

We performed in vivo diffusion tensor imaging (DTI) in a total of 33 patients with brain tuberculomas (BT). Thirteen of them had surgical excision of the lesion as it was clinically indicated, and in these samples matrix metalloproteinase-9 (MMP-9) expression was quantified. We correlated the results of DTI indices like fractional anisotropy (FA), mean diffusivity (MD), linear anisotropy (CL), planar anisotropy (CP) and spherical anisotropy (CS) with MMP-9 expression. In addition, the remaining 20 patients had serial DTI studies while on specific anti-tuberculous drug therapy and DTI indices in these patients were quantified. The FA, CL and CP significantly decreased while MD and CS significantly increased in BT compared to normal white matter. The FA, CL and CP showed negative correlation with MMP-9 while CS correlated positively. In serial follow-up studies in 20 patients FA, CL and CP showed significant increase while CS decreased significantly over time. We conclude that DTI indices show strong correlation with MMP-9 and these may be used as a surrogate marker of MMP-9 expression in BT. In addition, these indices may be of value in assessing the therapeutic response in patients with BT who are treated only with specific anti-tuberculous drugs.

Dynamic contrast-enhanced derived cerebral blood volume correlates better with leak correction than with no correction for vascular endothelial growth factor, microvascular density, and grading of astrocytoma.

OBJECTIVE: To look for the impact of leak correction on correlation of perfusion indices with microvessel density (MVD) and vascular endothelial growth factor (VEGF) in astrocytomas. METHODS: Dynamic contrast-enhanced magnetic resonance imaging was performed in 64 patients with varying grades of astrocytoma. Perfusion indices (ie, relative cerebral blood volume (rCBV) with and without leak correction, relative cerebral blood flow (rCBF), permeability (k(trans)), and leakage (v(e)) were quantified. MVD and VEGF-expressing cells were quantified from the excised tumor tissues and were correlated with perfusion metrics. RESULTS: Perfusion indices showed significant difference among the astrocytoma grades. The corrected rCBV correlated better with MVD and VEGF. The corrected rCBV correlated (r = 0.853, P = <0.001) strongly, whereas the uncorrected rCBV (r = 0.592, P = <0.001) and k(trans) (r = 0.498, P = 0.001) correlated moderately with tumor grade. The corrected rCBV discriminated 100% low-grade from high-grade astrocytoma, while uncorrected rCBV did this in 95.5% low-grade and 71.4% high-grade astrocytoma. CONCLUSIONS: Corrected rCBV better correlates with grade and is more accurate in discriminating low-grade from high-grade astrocytoma compared with uncorrected rCBV.

Utility of cysticercus fasciolaris antigen in Dot ELISA for the diagnosis of neurocysticercosis.

BACKGROUND: Clinical diagnosis of neurocysticercosis (NC) is established by CT scan and MRI. However, absolute diagnosis is not possible in a fair number of cases, and serological assays are used as adjunct. Besides, CT scan and MR imaging are resource-intensive tests and not practical for screening in endemic areas. AIM: To provide a low-cost, efficient, and reproducible assay for the detection of antibodies against cysticerci. Hence we have attempted to standardize and evaluate the diagnostic utility of the cysticercus fasciolaris antigen in a Dot ELISA assay for diagnosis of NC. SETTING AND DESIGN: Tertiary hospital-based, case-control series. MATERIALS AND METHODS: Confirmed cases of NC diagnosed by presence of ring lesions in CT scan or MR imaging with presence of scolex were taken as positive controls (n = 50). Negative controls (n = 50) included subjects with normal CT scan studies (n = 30) and diseased controls with ring lesions in CT scan confirmed to be neurotuberculosis (n = 20). Dot ELISA was standardized and validated with commercially available ELISA (UBI, USA) using sera from the study groups. STATISTICAL ANALYSIS: Chi-square test was used to compare the immunodiagnostic performance of the two tests. P value less than .05 (P < 0.05) was considered significant. RESULTS: The Dot ELISA had a sensitivity of 88% and specificity of 74% with a positive predictive value of 77.19% and negative predictive value of 81.06%. Likelihood ratios for a positive and a negative test were 3.4 and 0.2. The sensitivity and specificity of commercial ELISA were 92% and 84% respectively. Difference between the performances of the two tests was not significant statistically. CONCLUSIONS: Dot ELISA has sensitivity and specificity comparable to ELISA for the diagnosis of NC. The test is simpler, not requiring expertise and instrumentation. Further validation of the test as a screening tool is required.

Final results of MRC CRASH, a randomised placebo-controlled trial of intravenous corticosteroid in adults with head injury-outcomes at 6 months.

MRC CRASH is a randomised controlled trial (ISRCTN74459797) of the effect of corticosteroids on death and disability after head injury. We randomly allocated 10,008 adults with head injury and a Glasgow Coma Scale score of 14 or less, within 8 h of injury, to a 48-h infusion of corticosteroid (methylprednisolone) or placebo. Data at 6 months were obtained for 9673 (96.7%) patients. The risk of death was higher in the corticosteroid group than in the placebo group (1248 [25.7%] vs 1075 [22.3%] deaths; relative risk 1.15, 95% CI 1.07-1.24; p=0.0001), as was the risk of death or severe disability (1828 [38.1%] vs 1728 [36.3%] dead or severely disabled; 1.05, 0.99-1.10; p=0.079). There was no evidence that the effect of corticosteroids differed by injury severity or time since injury. These results lend support to our earlier conclusion that corticosteroids should not be used routinely in the treatment of head injury.

The role of diffusion-weighted imaging in the differential diagnosis of intracranial cystic mass lesions: a report of 147 lesions.

BACKGROUND: The objective of this study is to evaluate the sensitivity and specificity of DWI in differentiating brain abscesses from other intracranial cystic lesions. METHODS: One hundred fifteen patients with 147 cystic lesions (mean age, 26.4 year) were prospectively studied with DWI on a 1.5-T magnetic resonance imaging. Lesions appearing hyperintense on DWI with the ADC values of lower than 0.9 +/- 0.13 x 10(-3) mm(2)/s (mean +/- SD) were considered as brain abscess, whereas hypointense lesions on DWI with the ADC values 2.2 +/- 0.9 x 10(-3) mm(2)/s were categorized as nonabscess cystic lesions. RESULTS: Ninety-three of 97 brain abscess lesions were hyperintense on DWI, with significantly low (P = .0001) ADC value (0.87 +/- 0.05 x 10(-3) mm(2)/s) (mean +/- SEM), compared with 48 nonabscess lesions (2.89 +/- 0.05 x 10(-3) mm(2)/s). Four of 97 brain abscess lesions in 65 patients were false negative, and 2 of 50 nonabscess lesions in 50 patients were false positive for the diagnosis of brain abscess. The ADC value of the tumor cysts (2.9 +/- 0.05 x 10(-3) mm(2)/s) was significantly lower (P = .02) compared with benign cysts and neurocysticercosis (3.2 +/- 0.05 x 10(-3) mm(2)/s) among nonabscess group. The sensitivity of DWI for the differentiation of brain abscesses from nonabscesses was 96%; specificity, 96%; positive predictive value, 98%; negative predictive value, 92%; and accuracy of the test, 96%. CONCLUSIONS: Diffusion-weighted imaging has high sensitivity and specificity for the differentiation of brain abscess from other nonabscess intracranial cystic lesions.

Endoscopic transoral surgery for craniovertebral junction anomalies. Technical note.

Craniovertebral junction (CVJ) anomalies continue to be challenging for neurosurgeons because of the complex anatomy of this region. To date, microsurgical decompression via a transoral route is the standard treatment for anteriorly located compressive lesions of the cervicomedullary junction (CMJ). The results obtained by minimizing surgical trauma are fewer complications, shorter hospital stays, and reduced overall psychological burden. Endoscopic surgery is becoming a leading modality in minimally invasive neurosurgical treatment. The authors performed surgery in 11 patients with irreducible osseous dislocations resulting from CVJ abnormality during a 2-year period. Anterior CMJ decompression was achieved in all patients by performing neuroendoscopically controlled transoral excision of bone and soft tissues. The surgical technique and results will be discussed. The use of the endoscope offers several advantages in cases requiring a transoral approach to the lower clivus and atlantoaxial region. The use of minimally invasive endoscopic techniques has the potential to reduce the need for a wider cranial base opening and to decrease postoperative complications.