Localization of Vestibular Cortex Using Electrical Cortical Stimulation: A Systematic Literature Review

The vestibular system plays a fundamental role in body orientation, posture control, and spatial and body motion perception, as well as in gaze and eye movements. We aimed to review the current knowledge regarding the location of the cortical and subcortical areas, implicated in the processing of vestibular stimuli. The search was performed in PubMed and Scopus. We focused on studies reporting on vestibular manifestations after electrical cortical stimulation. A total of 16 studies were finally included. Two main types of vestibular responses were elicited, including vertigo and perception of body movement. The latter could be either rotatory or translational. Electrical stimulation of the temporal structures elicited mainly vertigo, while stimulation of the parietal lobe was associated with perceptions of body movement. Stimulation of the occipital lobe produced vertigo with visual manifestations. There was evidence that the vestibular responses became more robust with increasing current intensity. Low-frequency stimulation proved to be more effective than high-frequency in eliciting vestibular responses. Numerous non-vestibular responses were recorded after stimulation of the vestibular cortex, including somatosensory, viscero-sensory, and emotional manifestations. Newer imaging modalities such as functional MRI (fMRI), Positron Emission Tomography (PET), SPECT, and near infra-red spectroscopy (NIRS) can provide useful information regarding localization of the vestibular cortex.

Association between white matter lesions and Parkinson's disease: an impact on Postural/Gait difficulty phenotype and cognitive performance

BACKGROUND

White matter hyperintensities (WMHs) may be observed on Magnetic Resonance Imaging (MRI) in patients with Parkinson disease with or without vascular risk factors. Whether WMHs may influence motor and non-motor aspects of Parkinson disease is a subject of debate. The aim of this study is to evaluate the impact of WMH severity on various aspects of Parkinson disease in combination to the estimation of the impact of cerebrovascular risk factors.

MATERIALS AND METHODS

We included a cohort of patients with Parkinson's disease who underwent MRI examination. The Fazekas visual rating scale was used to assess the severity and location of WMHs, and patient clinical characteristics were correlated with MRI data.

RESULTS

All vascular risk factors were associated with higher Fazekas score in both periventricular and deep white matter. Periventricular white matter hyperintensities (PWMHs) and deep white matter hyperintensities (DWMHs) were associated with lower scores in the ACE-R cognitive assessment scale (p < 0.001). Furthermore, PWMHs and DWMHs severity was associated with higher UPDRS motor score (p < 0.001), while the Postural Instability Gait Difficulty (PIGD) phenotype was correlated with higher burden of WMHs.

CONCLUSIONS

Comorbid WMHs may contribute to multi-dimension dysfunction in patients with Parkinson disease and consequently the management of vascular risk factors may be crucial to maintain motor and non-motor functions in PD.

Bing-Neel syndrome presenting with bilateral lumbar radiculopathy: A case report of a rare clinical entity

The differential diagnosis of bilateral lower extremity weakness is broad. We present a very rare case of a 48-year old male patient, with walking difficulties due to Bing-Neel syndrome. On clinical examination, there was a significant loss of muscle power in all his lower extremities key-muscle groups. The lumbar spine magnetic resonance imaging (MRI) showed only mild degenerative changes, whereas the MRI of the head indicated a diffuse meningeal thickening at the right temporal region, characterized by significant enhancement after contrast administration. Serum protein electrophoresis detected an IgM-kappa monoclonal protein. The patient received intrathecal chemotherapy with methotrexate and cytarabine, and was started on oral ibrutinib 420mg daily. In conclusion, a past medical history of Waldenstrom macroglobulinemia in conjunction with neurological manifestations should alert the treating physician for Bing-Neel syndrome. A complete diagnostic imaging and serologic protocol helps in setting the final diagnosis. Steroids are part of the treatment, but should be given after the diagnosis is set. Neurosurgical intervention is indicated for histologic confirmation in the case of diagnostic uncertainty.

Clinically Silent Small Vessel Disease of the Brain in Patients with Obstructive Sleep Apnea Hypopnea Syndrome

Obstructive sleep apnea hypopnea syndrome (OSAHS) is associated with increased risk of cerebrovascular disease. The aim of the present study was to investigate the association between the presence of the small vessel disease (SVD) of the brain in patients with OSAHS. The study included 24 patients with moderate to severe OSAHS and 34 healthy volunteers. All the subjects underwent magnetic resonance imaging (MRI) of the brain, in order to sought periventricular white matter (PVWM), deep white matter (DWM) and brainstem SVD. Among patients with OSAHS, 79.1% had SVD (grade 1-3, Fazekas score) in DWM and 91.7% in PVWM while 22.4% had brainstem-white matter hyperintensities (B-WMH). Patients with OSAHS had a much higher degree of SVD in the DWM and PVWM compared to the control group (p < 0.001). The multivariate analysis showed an independent significant association of OSAHS with SVD (DWM and PVWM) (p = 0.033, OR 95% CI: 8.66 (1.19-63.08) and: p = 0.002, OR 95% CI: 104.98 (5.15-2141)). The same analysis showed a moderate association of OSAHS with B-WMH (p = 0.050, OR 15.07 (0.97-234.65)). Our study demonstrated an independent significant association of OSAHS with SVD and a moderate association of OSAHS with B-WMH.

Bing-Neel syndrome presenting with bilateral lumbar radiculopathy: A case report of a rare clinical entity

The differential diagnosis of bilateral lower extremity weakness is broad. We present a very rare case of a 48-year old male patient, with walking difficulties due to Bing-Neel syndrome. On clinical examination, there was a significant loss of muscle power in all his lower extremities key-muscle groups. The lumbar spine magnetic resonance imaging (MRI) showed only mild degenerative changes, whereas the MRI of the head indicated a diffuse meningeal thickening at the right temporal region, characterized by significant enhancement after contrast administration. Serum protein electrophoresis detected an IgM-kappa monoclonal protein. The patient received intrathecal chemotherapy with methotrexate and cytarabine, and was started on oral ibrutinib 420mg daily. In conclusion, a past medical history of Waldenstrom macroglobulinemia in conjunction with neurological manifestations should alert the treating physician for Bing-Neel syndrome. A complete diagnostic imaging and serologic protocol helps in setting the final diagnosis. Steroids are part of the treatment, but should be given after the diagnosis is set. Neurosurgical intervention is indicated for histologic confirmation in the case of diagnostic uncertainty.

Machine Learning in Meningioma MRI: Past to Present. A Narrative Review

Meningioma is one of the most frequent primary central nervous system tumors. While magnetic resonance imaging (MRI), is the standard radiologic technique for provisional diagnosis and surveillance of meningioma, it nevertheless lacks the prima facie capacity in determining meningioma biological aggressiveness, growth, and recurrence potential. An increasing body of evidence highlights the potential of machine learning and radiomics in improving the consistency and productivity and in providing novel diagnostic, treatment, and prognostic modalities in neuroncology imaging. The aim of the present article is to review the evolution and progress of approaches utilizing machine learning in meningioma MRI-based sementation, diagnosis, grading, and prognosis. We provide a historical perspective on original research on meningioma spanning over two decades and highlight recent studies indicating the feasibility of pertinent approaches, including deep learning in addressing several clinically challenging aspects. We indicate the limitations of previous research designs and resources and propose future directions by highlighting areas of research that remain largely unexplored. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 2.

Intermediate surgical outcome in patients suffering poor-grade aneurysmal subarachnoid hemorrhage. A single center experience

BACKGROUND

It is known that patients suffering poor-grade aneurysmal subarachnoid hemorrhage (aSAH) have a dismal prognosis. The importance of early intervention is well established in the pertinent literature. Our aim was to assess the functional outcome and overall survival of these patients undergoing surgical clipping.

MATERIAL AND METHODS

In the current retrospective study we included all consecutive poor-grade patients after spontaneous SAH who presented at our institution over an eight-year period. All participants suffering SAH underwent brain CT angiography (CTA) to identify the source of hemorrhage. We assessed the severity of hemorrhage according to the Fisher grade classification scale. All patients were surgically treated. The functional outcome was evaluated six months after the onset with the Glasgow Outcome Scale. Finally, we performed logistic and Cox regression analyses to identify potential prognostic risk factors.

RESULTS

Our study included twenty-three patients with a mean age of 53 years. Five (22%) patients presented with Hunt and Hess grade IV, and eighteen (78%) with grade V. The mean follow-up was 15.8 months, while the overall mortality rate was 48%. The six-month functional outcome was favorable in 6 (26%) patients. The vast majority of our patients died between the 15^th and the 60^th post-ictal days. We did not identify any statistically significant prognostic factors related to the patient's outcome and/or survival.

CONCLUSIONS

Poor-grade aSAH patients may have a favorable outcome with proper surgical management. Large-scale studies are necessary for accurately outlining the prognosis of this entity, and identifying parameters that could be predictive of outcome.

Dissecting the default mode network: direct structural evidence on the morphology and axonal connectivity of the fifth component of the cingulum bundle

OBJECTIVE

Although a growing body of data support the functional connectivity between the precuneus and the medial temporal lobe during states of resting consciousness as well as during a diverse array of higher-order functions, direct structural evidence on this subcortical circuitry is scarce. Here, the authors investigate the very existence, anatomical consistency, morphology, and spatial relationships of the cingulum bundle V (CB-V), a fiber tract that has been reported to reside close to the inferior arm of the cingulum (CingI).

METHODS

Fifteen normal, formalin-fixed cerebral hemispheres from adults were treated with Klingler's method and subsequently investigated through the fiber microdissection technique in a medial to lateral direction.

RESULTS

A distinct group of fibers is invariably identified in the subcortical territory of the posteromedial cortex, connecting the precuneus and the medial temporal lobe. This tract follows the trajectory of the parietooccipital sulcus in a close spatial relationship with the CingI and the sledge runner fasciculus. It extends inferiorly to the parahippocampal place area and retrosplenial complex area, followed by a lateral curve to terminate toward the fusiform face area (Brodmann area [BA] 37) and lateral piriform area (BA35). Taking into account the aforementioned subcortical architecture, the CB-V allegedly participates as a major subcortical stream within the default mode network, possibly subserving the transfer of multimodal cues relevant to visuospatial, facial, and mnemonic information to the precuneal hub. Although robust clinical evidence on the functional role of this stream is lacking, the modern neurosurgeon should be aware of this tract when manipulating cerebral areas en route to lesions residing in or around the ventricular trigone.

CONCLUSIONS

Through the fiber microdissection technique, the authors were able to provide original, direct structural evidence on the existence, morphology, axonal connectivity, and correlative anatomy of what proved to be a discrete white matter pathway, previously described as the CB-V, connecting the precuneus and medial temporal lobe.

The diagnostic accuracy of magnetic resonance angiography for blunt vertebral artery injury detection in trauma patients: A systematic review and meta-analysis

The role of magnetic resonance angiography (MRA) in the evaluation of patients with blunt vertebral artery has not been fully established. Our aim is to define the diagnostic accuracy of MRA in comparison to digital subtraction angiography (DSA) for the detection of blunt vertebral artery injury in trauma patients. A computer-assisted literature search of the PubMed, Scopus, Highwire, Web of Science, and LILACS was conducted, in order to identify studies reporting on the sensitivity and specificity of MRA in comparison to DSA for the detection of blunt vertebral artery injury in trauma patients. The Database search retrieved 91 studies. Five studies fulfilled our eligibility criteria. Two authors assessed the risk of bias and applicability concerns using QUADAS-2. Two-by-two contingency tables were constructed on a per-vessel level. Heterogeneity was tested by the statistical significance of Cochran's Q, and was quantified by the Higgins's I² metric. The pooled estimates of sensitivity and specificity for blunt vertebral artery injury detection with MRA in comparison to DSA were calculated based on the bivariate model. The meta-analysis was supplemented by subgroup and sensitivity analysis, as well as analysis for publication bias. There was significant clinical heterogeneity in the targeted population, inclusion criteria, and MRA related parameters. The reporting bias and applicability concerns were moderate and low, respectively. In the overall analysis, the sensitivity ranged from 25% to 85%, while the specificity varied from 65% to 99%, across studies. According to the bivariate model, the pooled sensitivity and specificity of MRA in the evaluation of patients with blunt vertebral artery was as high as 55% (95% CI 32.1%-76.7%), and 91% (95% CI 66.3%-98.2%), respectively. Subgroup analysis in terms of MRA sequence sensitivity of phase, the contrasted MRA (75% [95% CI 43%-92%]) seemed to be superior to the TOF MRA (46% [95%CI 20%-74%]). The addition of contrast enhancement did not seem to improve the diagnostic yield of MRA. The Egger's test did not identify any significant publication bias (p=0.2). An important limitation of the current meta-analysis is the small number of eligible studies, as well as the lack of studies on newer, high-field MR scanners. We concluded that MRA has a moderate diagnostic accuracy in the diagnosis of blunt vertebral artery injuries. Further studies on high-field magnetic resonance scanners are recommended.

The role of diffusion tensor imaging and fractional anisotropy in the evaluation of patients with idiopathic normal pressure hydrocephalus: a literature review

OBJECTIVE Diffusion tensor imaging (DTI) for the assessment of fractional anisotropy (FA) and involving measurements of mean diffusivity (MD) and apparent diffusion coefficient (ADC) represents a novel, MRI-based, noninvasive technique that may delineate microstructural changes in cerebral white matter (WM). For example, DTI may be used for the diagnosis and differentiation of idiopathic normal pressure hydrocephalus (iNPH) from other neurodegenerative diseases with similar imaging findings and clinical symptoms and signs. The goal of the current study was to identify and analyze recently published series on the use of DTI as a diagnostic tool. Moreover, the authors also explored the utility of DTI in identifying patients with iNPH who could be managed by surgical intervention. METHODS The authors performed a literature search of the PubMed database by using any possible combinations of the following terms: "Alzheimer's disease," "brain," "cerebrospinal fluid," "CSF," "diffusion tensor imaging," "DTI," "hydrocephalus," "idiopathic," "magnetic resonance imaging," "normal pressure," "Parkinson's disease," and "shunting." Moreover, all reference lists from the retrieved articles were reviewed to identify any additional pertinent articles. RESULTS The literature search retrieved 19 studies in which DTI was used for the identification and differentiation of iNPH from other neurodegenerative diseases. The DTI protocols involved different approaches, such as region of interest (ROI) methods, tract-based spatial statistics, voxel-based analysis, and delta-ADC analysis. The most studied anatomical regions were the periventricular WM areas, such as the internal capsule (IC), the corticospinal tract (CST), and the corpus callosum (CC). Patients with iNPH had significantly higher MD in the periventricular WM areas of the CST and the CC than had healthy controls. In addition, FA and ADCs were significantly higher in the CST of iNPH patients than in any other patients with other neurodegenerative diseases. Gait abnormalities of iNPH patients were statistically significantly and negatively correlated with FA in the CST and the minor forceps. Fractional anisotropy had a sensitivity of 94% and a specificity of 80% for diagnosing iNPH. Furthermore, FA and MD values in the CST, the IC, the anterior thalamic region, the fornix, and the hippocampus regions could help differentiate iNPH from Alzheimer or Parkinson disease. Interestingly, CSF drainage or ventriculoperitoneal shunting significantly modified FA and ADCs in iNPH patients whose condition clinically responded to these maneuvers. CONCLUSIONS Measurements of FA and MD significantly contribute to the detection of axonal loss and gliosis in the periventricular WM areas in patients with iNPH. Diffusion tensor imaging may also represent a valuable noninvasive method for differentiating iNPH from other neurodegenerative diseases. Moreover, DTI can detect dynamic changes in the WM tracts after lumbar drainage or shunting procedures and could help identify iNPH patients who may benefit from surgical intervention.

Cerebral vasospasm pharmacological treatment: an update

Aneurysmal subarachnoid hemorrhage- (aSAH-) associated vasospasm constitutes a clinicopathological entity, in which reversible vasculopathy, impaired autoregulatory function, and hypovolemia take place, and lead to the reduction of cerebral perfusion and finally ischemia. Cerebral vasospasm begins most often on the third day after the ictal event and reaches the maximum on the 5th-7th postictal days. Several therapeutic modalities have been employed for preventing or reversing cerebral vasospasm. Triple "H" therapy, balloon and chemical angioplasty with superselective intra-arterial injection of vasodilators, administration of substances like magnesium sulfate, statins, fasudil hydrochloride, erythropoietin, endothelin-1 antagonists, nitric oxide progenitors, and sildenafil, are some of the therapeutic protocols, which are currently employed for managing patients with aSAH. Intense pathophysiological mechanism research has led to the identification of various mediators of cerebral vasospasm, such as endothelium-derived, vascular smooth muscle-derived, proinflammatory mediators, cytokines and adhesion molecules, stress-induced gene activation, and platelet-derived growth factors. Oral, intravenous, or intra-arterial administration of antagonists of these mediators has been suggested for treating patients suffering a-SAH vasospam. In our current study, we attempt to summate all the available pharmacological treatment modalities for managing vasospasm.

Preoperative evaluation with FMRI of patients with intracranial gliomas

Introduction. Aggressive surgical resection constitutes the optimal treatment for intracranial gliomas. However, the proximity of a tumor to eloquent areas requires exact knowledge of its anatomic relationships to functional cortex. The purpose of our study was to evaluate fMRI's accuracy by comparing it to intraoperative cortical stimulation (DCS) mapping. Material and Methods. Eighty-seven patients, with presumed glioma diagnosis, underwent preoperative fMRI and intraoperative DCS for cortical mapping during tumor resection. Findings of fMRI and DCS were considered concordant if the identified cortical centers were less than 5 mm apart. Pre and postoperative Karnofsky Performance Scale and Spitzer scores were recorded. A postoperative MRI was obtained for assessing the extent of resection. Results. The areas of interest were identified by fMRI and DCS in all participants. The concordance between fMRI and DCS was 91.9% regarding sensory-motor cortex, 100% for visual cortex, and 85.4% for language. Data analysis showed that patients with better functional condition demonstrated higher concordance rates, while there also was a weak association between tumor grade and concordance rate. The mean extent of tumor resection was 96.7%. Conclusions. Functional MRI is a highly accurate preoperative methodology for sensory-motor mapping. However, in language mapping, DCS remains necessary for accurate localization.

Temporal pole proton preoperative magnetic resonance spectroscopy in patients undergoing surgery for mesial temporal sclerosis

OBJECT

The purpose of this prospective study was to compare the results of proton MR spectroscopy (MRS) in temporal poles in patients with unilateral mesial temporal sclerosis (MTS) with the histopathological findings of the resected temporal poles.

METHODS

A total of 23 patients (14 male and 9 female) with a mean age of 25.2 years (range 17-45 years) were included in this study, which was conducted over a 4-year period. All patients suffered medically refractory epilepsy due to unilateral, MRI-proven MTS, with no other imaging abnormalities. All participants underwent preoperative single-voxel proton MRS using a 3-T MRI unit. The hippocampi and temporal poles were examined bilaterally. The concentrations of N-acetyl-aspartate (NAA), choline (Cho), and creatine (Cr) were measured, and the NAA/Cho, NAA/Cr, and NAA/Cho+Cr ratios were calculated. All patients underwent anterior temporal lobectomy and ipsilateral amygdalohippocampectomy, and surgical specimens from the temporal poles were sent for histopathological examination. Comparisons of the spectroscopic and histopathological results of the resected temporal poles were performed. The modified Engel classification system was used for evaluating seizure outcome in the cohort.

RESULTS

The preoperative spectroscopic profiles of the sclerotic hippocampi were abnormal in all patients, and the contralateral hippocampus showed altered spectroscopic findings in 12 patients (52.2%). Spectroscopy of the temporal poles demonstrated severely decreased concentrations of NAA, markedly increased concentrations of Cho, and increased concentrations of Cr in the temporal pole ipsilateral to the MTS in 15 patients (65.2%). Similarly, the NAA/Cho, NAA/Cr, and NAA/Cho+Cr ratios were severely decreased in the temporal pole ipsilateral to the MTS in 16 patients (69.6%). Histopathological examination of the resected temporal poles demonstrated ischemic changes in 5 patients (21.7%), gliotic changes in 4 (17.4%), demyelinating changes in 3 (13.0%), and microdysplastic changes in 1 patient (4.3%). Comparisons of the spectroscopic and histopathological findings showed that the sensitivity of proton MRS was 100%, its specificity was 80%, its positive predictive value was 87%, and its negative predictive value was 100%. The mean follow-up time in this study was 3.4 years. At the end of the 2nd postoperative year, 17 patients (73.9%) were in Engel Class I, 5 (21.7%) were in Class II, and 1 (4.3%) was in Class III.

CONCLUSIONS

Proton MRS detected altered ipsilateral temporal pole metabolism in patients with unilateral MTS. These metabolic changes were associated with permanent histological abnormalities of the temporal pole. This finding demonstrates that MTS may be a more diffuse histological process, and exact preoperative knowledge of its temporal extent becomes of paramount importance in the selection of the best surgical approach in these patients. Further validation of the observations is necessary for defining the role of temporal pole proton MRS in cases of temporal lobe epilepsy.

A cervical ligamentum flavum cyst in an 82-year-old woman presenting with spinal cord compression: a case report and review of the literature

Introduction

We report on a very rare case of a cervical ligamentum flavum cyst, which presented with progressive myelopathy and radiculopathy. The cyst was radically extirpated and our patient showed significant recovery. A review of the relevant literature yielded seven cases.

Case presentation

An 82-year-old Greek woman presented with progressive bilateral weakness of her upper extremities and causalgia, cervical pain, episodes of upper extremity numbness and significant walking difficulties. Her neurological examination showed diffusely decreased motor strength in both her upper and lower extremities. Magnetic resonance imaging of her cervical spine demonstrated a large, well-demarcated cystic lesion on the dorsal aspect of her spinal cord at the C3 to C4 level, significantly compressing the spinal cord at this level, in close proximity to the yellow ligament and the C3 left lamina. The largest diameter of this lesion was 1.4 cm, and there was no lesion enhancement after the intravenous administration of a paramagnetic contrast. The lesion was surgically removed after a bilateral C3 laminectomy. The thick cystic wall was yellow and fibro-elastic in consistency, while its content was gelatinous and yellow-brownish. A postoperative cervical-spine magnetic resonance image was obtained before her discharge, demonstrating decompression of her spinal cord and dural expansion. Her six-month follow-up evaluation revealed complete resolution of her walking difficulties, improvement in the muscle strength of her arms (4+/5 in all the affected muscle groups), no causalgia and a significant decrease in her preoperative upper extremity numbness.

Conclusion

Cervical ligamentum flavum cysts are rare benign lesions, which should be included in the list of differential diagnosis of spinal cystic lesions. They can be differentiated from other intracanalicular lesions by their hypointense appearance on T₁-weighted and hyperintense appearance on T₂-weighted magnetic resonance images, with contrast enhancement of the cystic wall. Surgical extirpation of the cyst is required for symptom alleviation and decompression of the spinal cord. The outcome of these cysts is excellent with no risk of recurrence.

The role of intraoperative micro-Doppler ultrasound in verifying proper clip placement in intracranial aneurysm surgery

INTRODUCTION

Aneurysmal subarachnoid hemorrhage constitutes a clinical entity associated with high mortality and morbidity. It is widely accepted that improper clip placement may have as a result of incomplete aneurysm occlusion and/or partial or complete obstruction of an adjacent vessel. Various modalities, including intraoperative or postoperative digital subtracting angiography, near-infrared indocyanine green angiography, micro-Doppler ultrasonography (MDU), and neurophysiological studies, have been utilized for verifying proper clip placement. The aim of our study was to review the role of MDU during aneurysmal surgery.

METHODS

A literature search was performed using any possible combination of the following terms: "aneurysm," "brain," "cerebral," "clip," "clipping," "clip malpositioning," "clip repositioning," "clip suboptimal positioning," "Doppler," "intracranial," "microsurgery," "micro-Doppler," "residual neck," "ultrasonography," "ultrasound," and "vessel occlusion". Additionally, reference lists from the retrieved articles were reviewed for identifying any additional articles. Case reports and miniseries were excluded.

RESULTS

A total of 19 series employing intraoperative MDU during aneurysmal microsurgery were retrieved. All studies demonstrated that MDU accuracy is extremely high. The highest reported false-positive rate of MDU was 2 %, while the false-negative rate was reported as high as 1.6 %. It has been demonstrated that the presence of subarachnoid hemorrhage, specific anatomic locations, and large size may predispose to improper clip placement. Intraoperative MDU's technical limitations and weaknesses are adequately identified, in order to minimize the possibility of any misinterpretations.

CONCLUSION

Intraoperative MDU constitutes a safe, accurate, and low cost imaging modality for evaluating blood flow and for verifying proper clip placement during microsurgical clipping.

T2 FLAIR Increased Signal Intensity at the Posterior Limb of the Internal Capsule: Clinical Significance in ALS Patients

Amyotrophic lateral sclerosis (ALS) is characterized by progressive upper and lower motor neuron degeneration. A hyperintense signal on T2-weighted images along the corticospinal tract has been reported in patients with confirmed ALS. However, the specificity of this finding is under consideration, since it is also identified in healthy controls. Moreover, the correlation of this finding with disease progression has not yet been established. The purpose of our study is to evaluate the frequency with which this high signal appears in the posterior limb of the internal capsule (PLIC), compare visual with quantitative measurements, and correlate these with the progression of the disease. Our prospective clinical study included 24 patients and 51 healthy volunteers. In the ALS patient group, the diagnosis was established according to the criteria of El Escorial in the revised form of Airlee House. All patients were neurologically examined and underwent diagnostic procedures to exclude other diseases resembling ALS. The initial MRI was performed six months to two years after the onset of symptomatology. All ALS patients were clinically examined regarding their symptoms from the upper and lower motor neurons. Follow-up MRIs were performed in nine out of 24 patients over a period of six months. Signal changes in the PLIC are visually evaluated on FLAIR images, and are classified as distinct, mild or no signal change. Fractional anisotropy (FA) measurements are performed by placing a region of interest (ROI) in the PLIC bilaterally. Both findings are being compared. Mild signal changes were visualized in the PLIC in ten volunteers and seven patients. Distinct T2 FLAIR signal changes were visualized in the PLIC in seven ALS patients. No distinct signal change was visualized in the controls. Moreover this increased T2 FLAIR signal change became more accentuated with disease progress. FA measurements in patients were lower than in age-matched healthy subjects, with a further decrease with disease progression. Our findings indicate that although mild hyperintensity of the PLIC is not pathognomonic for ALS, detection of a distinct PLIC hyperintensity that gradually accentuates might actually be a sign of progressive ALS. This finding is supported by the progressively decreasing FA measurements. Larger numbers of patients need to be included and re-evaluated to obtain statistically significant results.

Role of the S100B serum biomarker in the treatment of children suffering from mild traumatic brain injury

OBJECT

The aim of this study was to provide a systematic update of the current literature regarding the clinical role of the S100B serum biomarker in the initial evaluation of children who have sustained a mild traumatic brain injury (TBI).

METHODS

Searches in MEDLINE were defined with the keywords "mild TBI children S100," "mild TBI pediatric S100," and "children S100 brain injury." From the pool of obtained studies, those that had the inclusion criteria of mild TBI only or mixed types of TBI but including detailed information about groups of children with mild TBI were used.

RESULTS

Few studies were identified and fewer included more than 100 cases. The prospective studies showed that the S100B biomarker levels could be influenced by patient age and the time frame between head injury and blood sampling. Moreover, extracranial sources of S100B or additional injuries could influence the measured levels of this biomarker. A normal value of S100B in children with mild TBI could rule out injury-associated abnormalities on CT scans in the majority of reported cases.

CONCLUSIONS

The vulnerability of S100B serum levels to the influences of patient age, blood sampling time, and extracranial S100B release limits the biomarker's role in the initial evaluation of children with mild TBI. The application of S100B in pediatric mild TBI cases has an elusive role, although it could help in selected cases to avoid unnecessary head CT scans.

Genetic basis of Parkinson disease

Over the past few years, considerable progress has been made in understanding the molecular mechanisms of Parkinson disease (PD). Mutations in certain genes are found to cause monogenic forms of the disorder, with autosomal dominant or autosomal recessive inheritance. These genes include alpha-synuclein, parkin, PINK1, DJ-1, LRRK2, and ATP13A2. The monogenic variants are important tools in identifying cellular pathways that shed light on the pathogenesis of this disease. Certain common genetic variants are also likely to modulate the risk of PD. International collaborative studies and meta-analyses have identified common variants as genetic susceptibility risk/protective factors for sporadic PD.

Serum and cerebrospinal fluid C-reactive protein levels as predictors of vasospasm in aneurysmal subarachnoid hemorrhage. Clinical article

OBJECT

Cerebral vasospasm is a common and potentially devastating complication of aneurysmal subarachnoid hemorrhage (aSAH). Inflammatory processes seem to play a major role in the pathogenesis of vasospasm. The C-reactive protein (CRP) constitutes a highly sensitive inflammatory marker. The association of elevated systemic CRP and coronary vasospasm has been well established. Additionally, elevation of the serum CRP levels has been demonstrated in patients with aSAH. The purpose of the current study was to evaluate the possible relationship between elevated CRP levels in the serum and CSF and the development of vasospasm in patients with aSAH.

METHODS

A total of 41 adult patients in whom aSAH was diagnosed were included in the study. Their demographics, the admitting Glasgow Coma Scale (GCS) score, Hunt and Hess grade, Fisher grade, CT scans, digital subtraction angiography studies, and daily neurological examinations were recorded. Serial serum and CSF CRP measurements were obtained on Days 0, 1, 2, 3, 5, 7, and 9. All patients underwent either surgical or endovascular treatment within 48 hours of their admission. The outcome was evaluated using the Glasgow Outcome Scale and the modified Rankin Scale.

RESULTS

The CRP levels in serum and CSF peaked on the 3rd postadmission day, and the CRP levels in CSF were always higher than the serum levels. Patients with lower admission GCS scores and higher Hunt and Hess and Fisher grades had statistically significantly higher levels of CRP in serum and CSF. Patients with angiographic vasospasm had higher CRP measurements in serum and CSF, in a statistically significant fashion (p < 0.0001). Additionally, patients with higher CRP levels in serum and CSF had less favorable outcome in this cohort.

CONCLUSIONS

Patients with aSAH who had high Hunt and Hess and Fisher grades and low GCS scores showed elevated CRP levels in their CSF and serum. Furthermore, patients developing angiographically proven vasospasm demonstrated significantly elevated CRP levels in serum and CSF, and increased CRP measurements were strongly associated with poor clinical outcome in this cohort.

Terson hemorrhage in patients suffering aneurysmal subarachnoid hemorrhage: predisposing factors and prognostic significance

OBJECT

The association of vitreous and/or subhyaloid hemorrhage with aneurysmal subarachnoid hemorrhage (SAH) has been frequently identified since the original description by Terson in 1900. In this prospective clinical study the authors examined the actual incidence of Terson hemorrhage in patients suffering aneurysmal SAH, they attempted to identify those parameters that could predispose its development, and they evaluated its prognostic significance in the overall patients' outcome.

METHODS

A total of 174 patients suffering aneurysmal SAH were included in this study. The admitting Glasgow Coma Scale scores (GCS), World Federation of Neurological Societies (WFNS) scale scores, Hunt and Hess grades, and Fisher grades were recorded. A careful ophthalmological evaluation was performed in all participants. The exact anatomical locations and the largest diameter of the dome of the ruptured aneurysms were also recorded. Surgical clipping or endovascular coiling was used in 165 patients. Clinical outcome was evaluated at discharge from the hospital by using the Glasgow Outcome Scale and the modified Rankin Scale. Periodic ophthalmological evaluations were performed for 2 years.

RESULTS

In this series, the observed incidence of Terson hemorrhage was 12.1%. Statistical analysis of our data demonstrated that patients with low GCS scores and high WFNS scores, Hunt and Hess grades, and Fisher grades had an increased incidence of Terson hemorrhage. The mortality rate for patients with Terson hemorrhage was 28.6%, whereas that for patients without Terson hemorrhage was 2.0%. Moreover, patients with Terson hemorrhage who survived had significantly worse outcomes than those in patients without Terson hemorrhage.

CONCLUSIONS

Terson hemorrhage constitutes a common SAH-associated complication. Its incidence is increased in patients with low GCS and high WFNS scores, and high Hunt and Hess and Fisher grades. Its presence is associated with increased mortality and morbidity rates.

The role of proton magnetic resonance spectroscopy in the diagnosis and categorization of cerebral abscesses

✓ Despite recent advances in neuroimaging, differentiation between cerebral abscesses and necrotic tumors with ring-type contrast enhancement can be puzzling at times. The introduction of advanced imaging techniques, such as diffusion-weighted imaging, has contributed to the identification of cerebral abscesses. However, differentiation may be impossible with imaging only. In this review the authors evaluate the role of proton magnetic resonance (MR) spectroscopy in differentiating between cerebral abscesses and necrotic tumors and address the spectral characteristics of intracranial abscesses. A large number of metabolites not detected in the normal brain spectra may be detected and give valuable information regarding the nature of the abscesses. Proton MR spectroscopy is a safe, noninvasive diagnostic modality, which could significantly increase the accuracy and specificity of conventional MR imaging in differentiating between malignant tumors and cerebral abscesses and provide valuable information regarding the cause of an abscess, as well as, its response to the chosen treatment.

The role of intraoperative micro-Doppler ultrasound in verifying proper clip placement in intracranial aneurysm surgery

We present the results of a retrospective study employing intraoperative micro-Doppler ultrasonography (MDU) in verifying proper clip placement during cerebral aneurysmal surgery. One hundred and thirty-four patients surgically treated for 147 intracranial aneurysms were studied. Thirteen patients harboring 17 aneurysms were surgically treated on an elective basis, while 121 patients with 130 aneurysms, presented with subarachnoid hemorrhage (SAH). Blood flow velocities of the parent and adjacent vessels as well as the aneurysmal sac were measured using a Conforma Micro-Doppler (Cook Vascular Inc., Leechburg, PA, USA). Pre- and post-operative cerebral angiography was obtained in all our patients. In 23 aneurysms (15.6%) there was decreased or absent flow in the parent vessel or in one of the adjacent vessels after clipping. In another 19 aneurysms (12.9%), MDU demonstrated flow through the aneurysmal dome even though the aneurysmal neck appeared to be totally obliterated. Presence of SAH, anatomic location and size of the aneurysm were associated with improper clip placement in a statistically significant fashion. The false positive rate for MDU was 2% while there were no false negative findings in our study. MDU appears to be a non-invasive, reliable alternative methodology to intra-operative angiography. This inexpensive method may lend itself to routine usage in aneurysm surgery.

Anterior cervical discectomy and fusion associated complications

STUDY DESIGN

Retrospective review study with literature review.

OBJECTIVE

The goal of our current study is to raise awareness on complications associated with anterior cervical discectomy and fusion (ACDF) and their early detection and proper management.

SUMMARY OF BACKGROUND DATA

It is known that ACDF constitutes one of the most commonly performed spinal procedures. Its outcome is quite satisfactory in the majority of cases. However, occasional complications can become troublesome, and in rare circumstances, catastrophic. Although there are several case reports describing such complications, their rate of occurrence is generally underreported, and data regarding their exact incidence in large clinical series are lacking. Meticulous knowledge of potential intraoperative and postoperative ACDF-related complications is of paramount importance so as to avoid them whenever possible, as well as to successfully and safely manage them when they are inevitable.

METHODS

In a retrospective study, 1015 patients undergoing first-time ACDF for cervical radiculopathy and/or myelopathy due to degenerative disc disease and/or cervical spondylosis were evaluated. A standard Smith-Robinson approach was used in all our patients, while an autologous or allograft was used, with or without a plate. Operative reports, hospital and outpatient clinic charts, and radiographic studies were reviewed for procedure-related complications. Mean follow-up time was 26.4 months.

RESULTS

The mortality rate in our current series was 0.1% (1 of 1015 patients, death occurred secondary to an esophageal perforation). Our overall morbidity rate was 19.3% (196 of 1015 patients). The most common complication was the development of isolated postoperative dysphagia, which observed in 9.5% of our patients. Postoperative hematoma occurred in 5.6%, but required surgical intervention in only 2.4% of our cases. Symptomatic recurrent laryngeal nerve palsy occurred in 3.1% of our cases. Dural penetration occurred in 0.5%, esophageal perforation in 0.3%, worsening of preexisting myelopathy in 0.2%, Horner's syndrome in 0.1%, instrumentation backout in 0.1%, and superficial wound infection in 0.1% of our cases.

CONCLUSION

Meticulous knowledge of the ACDF-associated complications allows for their proper management. Postoperative dysphagia, hematoma, and recurrent laryngeal nerve palsy were the most common complications in our series. Management of complications was successful in the vast majority of our cases.

Salvage of a failed odontoid screw

Complications associated with anterior odontoid screw fixation, although not very common can be quite troublesome. We report a patient with early back-out of the implanted screw and its salvage with re-implantation of a longer screw.

Supratentorial epidural hematoma of traumatic etiology in infants

INTRODUCTION AND BACKGROUND

Traumatic epidural hematoma (EDH) represents a rare head injury complication in infants. Its diagnosis can be quite challenging because its clinical presentation is usually subtle and nonspecific. In our current communication, we present our data regarding the presentation of infants with EDH, their management, and their long-term outcome.

MATERIALS AND METHODS

In a retrospective study, the hospital and outpatient clinic charts and imaging studies (head CT and skull X-rays) of 31 infants with pure, supratentorial EDH of traumatic origin were meticulously reviewed. Children Coma Scale score and Trauma Infant Neurologic Score (TINS) were also reviewed. The most common presenting symptom was irritability, which occurred in 18/31 (58.1%) of our patients. Pallor (in 30/31 patients) and cephalhematoma (in 21/31 patients) were the most commonly occurring clinical signs upon admission; both signs represent signs of significant clinical importance. Surgical evacuation via a craniotomy was required in 24/31 of our patients, while 7/31 patients were managed conservatively. The mortality rate in our series was 6.5% (2/31 patients), and our long-term morbidity rate was 3.2% (1/31 patients).

CONCLUSIONS

EDH in infants represents a life-threatening complication of head injury, which requires early identification and prompt surgical or conservative management depending on the patient's clinical condition, size of EDH, and presence of midline structure shift on head CT scan. Mortality and long-term morbidity are low with early diagnosis and prompt treatment.

Interobservational variation in determining fusion rates in anterior cervical discectomy and fusion procedures

The fusion rate represents one of the most commonly used criteria for evaluating the efficacy of spinal surgical techniques and the effectiveness of newly developed instrumentation and spinal implants. Reported fusion rates are not frequently supported by adequate information regarding by whom and how fusion was defined. In our prospective study we examined the fusion rate in patients undergoing first time anterior cervical discectomy and fusion for degenerative disease. Separate, well-defined radiographic fusion criteria were used and the 12-month post-operative X-rays were reviewed independently by a neurosurgeon, a neuroradiologist and an orthopedic surgeon, who were not involved in the patients' management. The observed fusion rates were 77.3, 87.8 and 84.7% respectively. Statistical analysis demonstrated concordance rates of 87.8, 91 and 91.4% and Kappa coefficients of 0.585, 0.620 and 0.723 for each pair of evaluators. Another set of ratings of the same radiographs, by the same interviewers, was obtained 6 weeks after the initial one. The reported fusion rates were 78.2% for the neurosurgeon, 87.4% for the orthopedic surgeon, and 86.1% for the neuroradiologist. Statistical analysis demonstrated intra-observer concordance rates of 98.7, 92.2 and 97.9% respectively, while the Kappa coefficients were 0.963, 0.677 and 0.907 for each reviewer. Our findings confirm the necessity of defining and describing criteria for fusion whenever this rate is reported in clinical series. The lack of widely accepted, well-defined criteria makes comparison of these results difficult. The development of a well organized, prospective clinical study in which fusion and outcome will be assessed by both clinical and radiographic parameters could significantly contribute to a more accurate evaluation of overall outcome of cervical spinal procedures.

Spontaneous resolution of acute cranial subdural hematomas

Acute cranial subdural hematoma (SDH) represents a common consequence of traumatic brain injury. The vast majority of acute SDHs larger than 10mm in thickness require immediate surgical evacuation. In rare occasions, however, spontaneous resolution may occur. In our current communication, we present four cases of spontaneous resolution of acute cranial SDH. Further more, the proposed theories explaining spontaneous resolution of acute SDH, as well as, clinical parameters and imaging characteristics that might predict such phenomenon, are also reviewed. The possibility of spontaneous resolution of an acute SDH, although remote, may impact the decision making process regarding the management of these patients under certain conditions.

Clinical implications of quantitative infrared pupillometry in neurosurgical patients

Pupillometry has been widely employed in the evaluation of a large number of pathological conditions, including intracranial pathology. The recent introduction of a portable, user-friendly, infrared pupillometer (ForSite, NeurOptics Inc., Irvine, CA) has enabled the accurate and reproducible measurement of several pupillary parameters, such as maximum and minimum apertures, constriction and dilation velocities, and latency period. It should be noted that various clinical conditions, especially neurological and ocular diseases, as well as numerous medications, may interfere with the measurements. Furthermore, a number of physiological parameters, such as the intensity of retinal illumination, the level of patient's alertness, the intensity of ambient light, as well as the time of day that the examination is performed may alter the obtained values. The potential implications of pupillometry in the clinical assessment of neurosurgical patients, including its complex relationship to intracranial pressure changes, mandate the undertaking of prospective clinical studies validating the clinical significance of this noninvasive, diagnostic modality.

Pediatric golf-related head injuries

OBJECTIVES

Golf-related head injuries constitute an increasingly common mechanism of head trauma in children. We present our experience with 33 pediatric cases of golf-associated head injury, with special emphasis in the type of injury, management strategy, and outcome.

MATERIALS AND METHODS

A thorough review of all children admitted to our hospital with golf-related head injury during a period of 10 years (1 January 1994 to 31 December 2003) was undertaken. The patients' charts, operative reports, imaging studies, and follow-up data were analyzed. A comparison of our findings with those described in the pertinent literature was subsequently performed.

CONCLUSIONS

Pediatric golf-related head trauma is a significant cause of sport-associated head injury, sometimes harboring a very dismal prognosis. The significance of establishing a task force for the prevention of these injuries cannot be overemphasized.

Extrusion of a Screw Into the Gastrointestinal Tract After Anterior Cervical Spine Plating

In this case report of a screw extrusion into the gastrointestinal tract of a patient 16 months after anterior cervical discectomy and fusion (ACDF), the authors describe a rare but potentially lethal complication and review the literature on this topic. A 70-year-old white man with a surgical history of ACDF at C3-4 underwent an ACDF at C5-6 with autologous bone graft and a dynamic plate using locking, expanding screws. Sixteen months after the operation the patient presented with severe dysphagia. Radiographic findings indicating pulling out of the implanted plate and screws prompted a surgical removal of the instrumentation. One of the screws was not found during the operation and was visualized after surgery by abdominal radiography in the right lower abdominal quadrant. A subsequent Gastrografin swallowing test revealed an esophageal tear. The screw was removed endoscopically and the patient received antibiotics and had no oral intake for 4 days. He was discharged without symptoms on a soft mechanical diet; at 24 weeks, follow-up revealed no changes or symptoms. Screw extrusion into the gastrointestinal tract following ACDF is a rare but potentially lethal complication. The use of locking, expanding screws does not extinguish the risk of this complication, particularly in cases of suboptimal initial placement of the anterior instrumentation. Close follow-up is of paramount importance in detecting any pull-out of the implanted plate. Any signs of postoperative dysphagia or throat soreness should prompt immediate evaluation of the patient and, if indicated, surgical removal of the failed instrumentation.

Long-term surgical outcome in patients with intracranial hydatid cyst

BACKGROUND

Cerebral hydatid cysts account for up to 3.6% of all intracranial space-occupying lesions, in endemic countries. The vast majority of patients affected are children. Computed tomography (CT) and magnetic resonance imaging (MRI) have greatly contributed to a more accurate diagnosis of hydatids. However, correct pre-operative diagnosis still remains quite puzzling. Extirpation of the intact cyst is the treatment of choice, resulting in most cases to a complete recovery.

METHOD

In our retrospective study, we have reviewed 76 cases of intra-cranial hydatid disease operated on in our hospital over a 22 year period. Presenting clinical symptoms and signs and the radiological findings on CT and MRI were documented. Albendazole was given preoperatively to patients with giant (>5 cm) or multiple cysts and postoperatively to all patients. The follow-up period ranged from 12 months to 22 years and the outcome was assessed using the Glasgow Outcome Scale (GOS).

FINDINGS

Sixty seven (95.7%) of our patients were children. Increased intracranial pressure and papilledema were the predominant findings in this group, whereas focal neurological deficits were most prevalent in adults. CT and MRI revealed round cystic lesions, isodense and iso-intense respectively to cerebrospinal fluid (CSF), with no rim enhancement or perifocal edema. Multiple cysts were identified in 3 cases. Extirpation of the cyst without rupture was accomplished in 56 patients (73.7%). Recurrences occurred in 19 patients (25%). 4 patients (5.3%) died within 6 months after surgery; 3 of these patients had multiple cysts and one died shortly after the operation due to anaphylactic shock following intra-operative rupture of the cyst.

CONCLUSION

Long-term follow-up confirms that intracranial hydatid cysts should always be surgically removed without rupture; the outcome remains excellent in these cases. Correct preoperative diagnosis is vital for the successful outcome of surgery. A high index of suspicion is therefore required in endemic areas despite the availability of advanced neuro-imaging. Medical treatment with albendazole seems to be beneficial both pre- and post-operatively. Newer diagnostic methodologies, such as MR spectroscopy and MR diffusion weighted imaging, might lend themselves to the diagnosis of intracranial hydatid cysts.

Cervical epidural hematoma in children: a rare clinical entity

✓ Pediatric spinal epidural hematoma is a very rare clinicopathological entity. In the vast majority of cases, spinal epidural hematomas have a nonspecific clinical presentation; this, along with their rapid progression, makes their early diagnosis and prompt surgical evacuation critical. Magnetic resonance imaging is the neuroimaging modality of choice, whereas hemilaminectomy or laminectomy is the indicated surgical intervention. The outcome is good when hematoma evacuation is performed before the onset of complete sensorimotor paralysis.

In this communication, the authors describe a 12-year-old girl with a traumatic acute cervical epidural hematoma. This lesion was successfully evacuated through a hemilaminectomy, and the patient had an excellent outcome. The pertinent literature is reviewed in terms of the incidence, origin, management, and prognosis of this rare and potentially disastrous clinical entity.

Review of the literature regarding the relationship of rebleeding and external ventricular drainage in patients with subarachnoid hemorrhage of aneurysmal origin

Acute hydrocephalus is a well-documented complication of subarachnoid hemorrhage. The insertion of external ventricular drainage (EVD) has been the standard of care in the management of this complication, aiming primarily at immediate improvement of the clinical condition of these patients, making them more suitable candidates for surgical or endovascular intervention. In our current communication, we review the pertinent literature regarding the relationship of rebleeding and EVD. Several studies have implicated a significantly increased risk of rebleeding in patients with EVD, compared with patients without it. Abrupt lowering of the intracranial pressure could lead to rebleeding due to decreased transmural pressure or removal of the clot sealing the previously ruptured aneurysm. However, a variety of parameters that could affect the rebleeding rate, such as the timing of surgery, the timing and duration of drainage, the size of the aneurysm, as well as the severity of the initial hemorrhage, do not seem to have been adequately explored in the majority of these studies. In addition, a number of clinical trials have failed to provide evidence for the negative role of EVD in the development of rebleeding. Conclusively, further long-term multi-center studies are required in order to establish the exact nature of the relationship between EVD and rebleeding after aneurysmal subarachnoid hemorrhage.

Surgical Treatment of Acute Type II and Rostral Type III Odontoid Fractures Managed by Anterior Screw Fixation

OBJECTIVES

In the present study, the authors comment on their experience with anterior odontoid screw fixation in the management of odontoid fractures, in an attempt to further assess the safety and the efficacy of this procedure.

MATERIALS AND METHODS

A retrospective analysis of 50 consecutive patients with reducible type II or rostral type III odontoid fractures, operated at our hospital with anterior odontoid screw fixation. Radiographic bony fusion, complications, and clinical outcome were evaluated.

RESULTS

Solid bony fusion was evident in 38 (90.5%) of the patients. One mechanical instrumentation-related complication occurred, without clinical significance. No other major complications related to the procedure were noted. A satisfactory range of motion in the cervical spine was observed in all patients.

CONCLUSIONS

Anterior odontoid screw fixation is a safe and effective procedure for the treatment of type II and rostral type III odontoid fractures. Compliance to the specific indications and contraindications of this operation is crucial for optimal outcome.

Cerebrospinal fluid fistula secondary to dural tear in anterior cervical discectomy and fusion: case report

STUDY DESIGN

A case of cerebrospinal fistula secondary to a dural tear during anterior cervical discectomy and fusion.

OBJECTIVES

To report a quite rare complication associated with anterior cervical discectomy and remind the spinal surgeons that this infrequent complication can easily become a very serious one.

SUMMARY OF BACKGROUND DATA

Anterior cervical discectomy represents one of the most commonly performed spinal procedures. Of the associated complications, accidental dural tear can lead to the development of a cerebrospinal fluid (CSF) fistula. Although this complication has been mentioned in several clinical series, the body of knowledge regarding incidence and appropriate treatment is definitely limited.

METHODS

After undergoing anterior cervical discectomy and fusion for an extruded disc at the C4-C5 level, a CSF fistula developed in a 37-year-old patient as a result of a dural tear. The patient underwent a second procedure for surgical wound revision, meticulous dural opening coverage, and insertion of a lumbar drain for draining CSF for 5 days.

RESULTS

The patient was hospitalized for 5 days and then discharged with no evidence of CSF leakage. His follow-up of 9 months revealed complete resolution of his preoperative symptomatology and no other problems associated with the complication of the CSF fistula.

CONCLUSION

Early identification of this complication and aggressive treatment with insertion of lumbar drain, CSF drainage for 4-5 days, and coverage of the dural tear with fibrin sealant or autologous fascia graft can prevent the development of any consequences.

Results of long-term follow-up in patients undergoing anterior screw fixation for type II and rostral type III odontoid fractures

STUDY DESIGN

Retrospective analysis of the fusion rate of a group of 38 patients having undergone anterior screw fixation for type II and "shallow" type III odontoid fractures. OBJECTIVE.: To determine primarily the long-term fusion rate after anterior screw fixation and to study the clinical characteristics of patients that have a statistically significant or nonsignificant influence on successful outcome.

SUMMARY OF BACKGROUND DATA

Long-term outcome of anterior screw fixation for odontoid fractures has been evaluated in very few studies. This information should be critical for further establishing this technique as a major therapeutic strategy for these cases.

METHODS

Thirty-eight patients, 25 males and 13 females (with mean age 48.4 +/- 0.4 years), with type II and rostral type III odontoid fractures, underwent anterior cannulated screw fixation during a 62-month period. Radiologic examination of the cervical spine with plain radiographs was performed at 6 weeks, and 2, 6, 12, and 24 months, while computerized tomography of the upper cervical spine (C1-C3) was obtained at 6 months after surgery. Follow-up was available for 31 patients, and the follow-up time ranged from 39 to 87 months (mean 58.4).

RESULTS

Radiographic evaluation of the follow-up group showed satisfactory bony fusion and no evidence of abnormal movement at the fracture site in 27 (87.1%) patients. Pseudarthrosis developed in 4 (12.9%) patients; however, 3 (9.6%) of them without instability and 1 (3.2%) with instability. One (3.2%) patient had an instrumentation failure without instability.

CONCLUSIONS

In our series, anterior odontoid screw fixation comprised a safe therapeutic modality with high stability and low mechanical failure rates during short-term and long-term follow-up.

Is non-invasive monitoring of intracranial pressure waveform analysis possible? Preliminary results of a comparative study of non-invasive vs. invasive intracranial slow-wave waveform analysis monitoring in patients with traumatic brain injury

BACKGROUND

An increasing body of evidence supports the concept that intracranial pressure (ICP) slow B waves represent the auto-regulatory response of spontaneous fluctuations of cerebral perfusion pressure. A relationship between cerebral auto-regulation and clinical outcome in patients with traumatic brain injury has also been established. The objective of our prospective clinical study was to compare the B slow ICP waves obtained invasively by standard ICP monitoring to those obtained noninvasively using a new ultrasound technology.

MATERIAL/METHODS

In the participating institutions, over a period of six months, thirteen consecutive patients (8 males and 5 females) with severe closed head injuries (GCS < 8) were included in our IRB-approved study. Intracranial pressure and B slow waves, as well as arterial blood pressure and waveforms, were evaluated by standard invasive techniques. Additionally, a new non-invasive ultrasound device, Vittamed (Telematics Scientific Laboratory, Kaunas, Lithuania), was employed for monitoring intracranial blood volume slow waves. Using these modalities, it was possible to compare the changes that occurred with invasive monitoring (Correlation factor RI) and the changes that occurred using non-invasive technology (Correlation factor RN).

RESULTS

Bland Altman plot analysis showed positive correlation between the invasively and non-invasively obtained slow intracranial B waves (2sigma = 8.9%, p < 0.0001) and cerebral auto-regulation indexes (RI and RN) (SD = 5%, p < 0.0001). Positive RI and RN values were correlated with poor clinical outcome.

CONCLUSIONS

Ultrasonographic technology (Vittamed) may have significant application in non-invasive continuous cerebrovascular auto-regulation monitoring in patients with severe head injuries.

Correlation of the amount of disc removed in a lumbar microdiscectomy with long-term outcome

STUDY DESIGN

The authors conducted a prospective clinical study.

OBJECTIVES

The objectives of this study were to investigate the relationship, if any, of the amount of removed disc in a standard first-time lumbar microdiscectomy and long-term outcome as well as recurrence and postoperative instability rates.

SUMMARY OF BACKGROUND DATA

There is lack of data on the amount of disc that needs to be removed during a lumbar microdiscectomy. Anecdotal data and dogmatic recommendations make the subject even more controversial.

MATERIAL AND METHODS

A total of 106 patients underwent a standard first-time lumbar microdiscectomy for medically refractory sciatica resulting from a herniated disc. The removed disc material was weighted. All patients were clinically followed for at least 2 years and outcome was evaluated by using pain intensity, presence of physical signs, functional capacity, return to work, and patients' opinion regarding their outcome.

RESULTS

The mean amount of disc removed was calculated at 2.1 +/- 0.9 g. Ninety-one patients had an excellent outcome and returned to their preoperative work. Fifteen patients had persistent symptomatology and underwent extensive radiographic workup, which revealed a disc recurrence at the same level in 8 patients and first-degree instability in 3 patients. In the remaining 4 patients, no clinical or radiographic abnormality was proven and the patients were treated conservatively, whereas all of them had applied for disability. No relationship was proven between the amount of the removed disc and the intraoperative blood loss or the intraoperative complication rate. Our statistical analysis showed no correlation between the amount of the removed disc and the long- term outcome, recurrence rate, or postoperative instability.

CONCLUSIONS

The degree of disc removal did not influence the outcome or complication rate in our clinical series.

C1-C2 Transarticular Screw Fixation for Atlantoaxial Instability

OBJECTIVES

The atlantoaxial segment of the cervical spine is commonly destabilized in a variety of disorders. Transarticular screw fixation of the C1-C2 joint has been proposed as a biomechanically superior therapeutic modality. The authors present their experience with this technique.

METHODS

A retrospective analysis of 23 patients treated with this technique was performed. The mean follow-up period was 39.5 +/- 0.1 months.

RESULTS

Mean duration of hospitalization was 3.4 +/- 0.1 days (range, 2 to 11 days). No intraoperative or early postoperative complications were detected. Four patients (17.4%) had postoperative complications unrelated to the primary procedure. The position of the screw was judged as satisfactory in 21 patients (91.3%). Two patients (8.7%) with suboptimal positioning of the screws were neurologically intact but needed no reoperation. Solid osseous fusion was detected in 19 patients (82.6%).

CONCLUSIONS

Transarticular C1-C2 screw fixation appears to be a safe and surgically reliable technique. Criteria for its application and refinements in its technical considerations continue to advance its clinically versatile therapeutic potential.

Intracranial Temperature: Is It Different Throughout the Brain?

INTRODUCTION

Accurate knowledge of cerebral temperature is assuming increasing importance, because its manipulation is employed more frequently for cerebral protection.

PURPOSE

This prospective clinical study was performed to examine how well intraventricular temperature reflects global cerebral temperature.

METHODS

The intraventricular temperature was monitored in 61 patients who were admitted to the neurointensive care unit for various intracranial pathological entities. A temperature probe coupled to an intraventricular pressure monitor was inserted in the lateral ventricle. At the conclusion of the monitoring process, a second intraventricular temperature probe was inserted in the ipsilateral ventricle and the previous one was carefully and gradually removed. During that removal, the intraparenchymal temperature was monitored for 90 minutes at 1-cm intervals throughout the brain parenchyma.

RESULTS

The mean intraventricular temperature was 37.84+/-1.03 degrees C, whereas the mean systemic (rectal) temperature was 37.65+/-0.68 degrees C. At 1 cm outward distance from the lateral ventricle, the mean intraparenchymal temperature was 38.21+/-0.32 degrees C, 38.39+/-0.33 degrees C at 2 cm, 38.27+/-0.31 degrees C at 3 cm, 38.26+/-0.29 degrees C at 4 cm, and, finally, 37.9+/-0.50 degrees C at 5 cm. Statistical analysis of the recordings showed no statistically significant differences between the intraventricular and intraparenchymal temperatures and intraventricular and rectal temperatures. No statistically significant correlation was established between the intraventricular temperature and parameters, such as the patient's age, sex, and admitting diagnosis.

CONCLUSION

Cerebral temperature was relatively stable through the brain parenchyma in this study. Because intraventricular temperature accurate.

Disassociation between intracranial and systemic temperatures as an early sign of brain death

Intracranial temperature and its normal variation, as well as its response to various pathologic conditions, has become a critical component of monitoring in neurosurgical intensive care. In a prospective clinical study of 54 neurosurgical patients, intracranial pressure, cerebral perfusion pressure, and intraventricular and systemic temperatures were monitored in a neurosurgical intensive care unit. All of our patients' intraventricular temperatures were initially higher than their systemic temperatures. In 11 patients, the intraventricular temperature became lower than the systemic temperature, in a median time of 4.43 hours (range, 4.21-5.18 hours), prior to any changes in intracranial and cerebral perfusion pressures. Reversal of the disassociation between intraventricular and systemic temperatures may be an early marker of patients with a poor prognosis.

In vivo proton magnetic resonance spectroscopy of brain tumors

The ability of magnetic resonance spectroscopy (MRS) to differentiate neoplastic brain cells and their metabolic and structural characteristics is evaluated. We examined 120 patients with brain tumors using a 1.5-tesla MRI unit and MRS. The peak areas of N-acetyl-aspartate (NAA), phosphocreatine-creatine (Pcr-Cr), choline-containing compounds (Cho), lactate, lipids, myoinositol, amino acids and the ratios of NAA/Pcr-Cr, NAA/Cho and Cho/Pcr-Cr were calculated by a standard integral algorithm. In normal brain tissue, the following metabolites were identified: NAA at 2.0 ppm, Pcr-Cr at 3.0 ppm and Cho at 3.2 ppm. The different concentrations of the metabolites examined and their role in the biochemical profile of different types of tumors are discussed. The confidence interval of the MRS versus pathology was between 0.9 and 0.954, while it was between 0.52 and 0.631 for MRI versus pathology. The Cho/Pcr-Cr ratio is a very important malignancy marker for histologic tumor grading of astrocytomas. The greater this ratio, the higher the grade of the astrocytoma. NAA/Pcr-Cr together with Cho/Pcr-Cr help specify the presence or absence of a neoplasm. Proton MRS is a useful and promising diagnostic modality not only in diagnosing but also in grading solid brain tumors.

Results and complications from the use of a frameless stereotactic microscopic navigator system

We present a series of 21 patients, 12 males and 9 females, aged 41-76 years, with the preoperative diagnosis of a brain tumor. Both preoperatively and postoperatively, all of our patients underwent either a brain computed tomography (CT) or magnetic resonance imaging (MRI). All the radiographic studies were taped and loaded preoperatively in the Stereotactic Microscopic Navigator (SMN) workstation (Zeiss, Germany). The mean duration of this procedure was 25 +/- 6 min. All our patients were operated on in our institute with the use of the SMN system. The specificity of tumor localization using CT scan was 2.20 +/- 0.25 mm and for the MRI scan 2.6 +/- 0.25 mm. As assessed by postoperative radiographic studies, total gross tumor resection was possible in 20 patients (95.23%). No major intraoperative or early postoperative complications were noted in our series. We believe that the SMN system is a safe, well-tolerated by the patients and simple method with extremely high accuracy and specificity.

Postoperative lumbar microdiscectomy pain. Minimalization by irrigation and cooling

STUDY DESIGN

Seventy patients undergoing de novo lumbar microdiscectomy were prospectively randomized into a control group and a group in which cold intraoperative wound irrigation along with postoperative wound cooling was used. Postoperative analgesia requirements and length of hospital stay were analyzed and correlated.

OBJECTIVES

To evaluate the role of intraoperative cold irrigation and postsurgical cooling in minimizing postoperative lumbar discectomy pain.

SUMMARY OF BACKGROUND DATA

Regulated hypothermia has been used frequently in pain reduction; however, the efficacy of such a strategy in lumbar disc procedures has not been established.

METHODS

Seventy patients (43 men and 27 women), operated on the first time for lumbar disk herniation were prospectively randomized into two groups. A standard microdiscectomy was performed on all patients. In cohort A the wound site was irrigated with a cold (18 C) 5% bacitracin solution for 5 minutes. Additionally, a cooling microtemperature pump was placed on the wound site for 24 hours after surgery. The patients in the control group (cohort B) were treated in a standard fashion without additional hypothermic therapy. All patients received postoperative analgesia through a self-administered morphine pump. The amount of postoperative analgesia received was calculated in morphine equivalents per kilogram. The length of hospital stay was also noted.

RESULTS

The total amount of pain medication was significantly smaller in cohort A than in the control group (cohort B). For the statistical analysis of the results, covariate analyses for both the length of hospital stay and the morphine dose were used, demonstrating a statistically significant difference with P = 0.0001. No postoperative wound infection was noted in either group.

CONCLUSIONS

Intraoperative and postoperative wound site cooling is a safe, inexpensive, and efficient therapeutic method. It reduces the patients' postoperative pain, promotes earlier ambulation and decreases the length of hospital stay.