Christos Koutsarnakis

A Laboratory Manual for Stepwise Cerebral White Matter Fiber Dissection

OBJECTIVEnWhite matter fiber dissection is an important method in acquiring a thorough neuroanatomic knowledge for surgical practice. Previous studies have definitely improved our understanding of intrinsic brain anatomy and emphasized on the significance of this technique in modern neurosurgery. However, current literature lacks a complete and concentrated laboratory guide about the entire dissection procedure. Hence, our primary objective is to introduce a detailed laboratory manual for cerebral white matter dissection by highlighting consecutive dissection steps, and to stress important technical comments facilitating this complex procedure.nnnMETHODSnTwenty adult, formalin-fixed cerebral hemispheres were included in the study. Ten specimens were dissected in the lateromedial and 10 in the mediolateral direction, respectively, using the fiber dissection technique and the microscope.nnnRESULTSnEleven and 8 consecutive and distinctive dissection steps are recommended for the lateromedial and mediolateral dissection procedures, respectively. Photographs highlighting various anatomic landmarks accompany every step. Technical recommendations, facilitating the dissection process, are also indicated.nnnCONCLUSIONSnThe fiber dissection technique, although complex and time consuming, offers a three-dimensional knowledge of intrinsic brain anatomy and architecture, thus improving both the quality of microneurosurgery and the patients standard of care. The present anatomic study provides a thorough dissection manual to those who study brain anatomy using this technique.

Twelve-Year Hospital Outcomes in Patients with Idiopathic Hydrocephalus

OBJECTIVEnThe aim of this study was to examine patients who were admitted for the first-ever shunting for idiopathic normal pressure hydrocephalus (INPH) during a 12-year period, in terms of variation rate, patient demographic characteristics, shunt procedures, postoperative complications, and hospital outcome.nnnMETHODSnAn electronic database which included all shunted patients (1998 to 2009) was used to retrieve demographic, clinical, and hospital outcome data. INPH patient identification was based on clinical and imaging diagnostic criteria.nnnRESULTSnINPH patients (n = 238) who had undergone shunting were identified. The mean age and male to female ratio of INPH patients were 73.3 (± 7) years and 1.28:1, respectively.The number of surgically managed INPH cases and proportion of INPH-related shunting procedures rose consecutively during the second and last third of the study period. Ventriculoperitoneal shunts (n = 129; 54.2%) were the most commonly used configurations, followed by ventriculoatrial (n = 108; 45.4%) and lumboperitoneal (n = 1; 0.4%). Intrahospital shunt-related complications were hematomas (0.84%), meningitis (0.42%), and status epilepticus (0.42%). A favorable outcome was reported for 66.8% of patients; 31.5% showed no change. Overall inpatient mortality was 1.7%.nnnCONCLUSIONnThe quantitative findings indicate a progressive rise in the number of surgically managed INPH patients that parallels a rise in the proportion of INPH-related shunting procedures. Contributing factors are likely to include improved diagnosis and an increase in awareness of the INPH syndrome by referring physicians.

The role of white matter dissection technique in modern neuroimaging: can neuroradiologists benefit from its use?

Current literature has repeatedly stressed the significance of the detailed knowledge of brain white matter anatomy in modern neurosurgery [3]. Acquiring this knowledge refines both presurgical planning and surgical strategy to achieve maximal tumor resection with minimal postoperative neurological morbidity. Interestingly, modern neuroimaging methods, such as DTI, have noninvasively mapped several white matter brain pathways and have also allowed the study of the spatial relationship of brain lesions to intrinsic fiber bundles. Hence, their role, not only in modern neurosurgery but also in the field of neuroscience generally, is deemed pivotal [2]. Even though these novel radiology studies are elegant and elective they are, thus far, prone to multiple artifacts due to the prominent ‘‘crossing’’ and ‘‘termination’’ problems [4]. Therefore, the exact configuration of fiber tracts and anatomical features that have been revealed by the traditional laboratory methods of anatomical dissection cannot be thoroughly resembled, at present, with these methods. This drawback is further accentuated when studying brain lesions with mass effect since the accuracy of the existing methods is decreased [5]. In this context, the white matter fiber dissection technique introduced by Klinger in 1935 and popularized by Yasargil in the intervening decades is a scientific procedure performed in neuroanatomy laboratories that aims in providing a thorough three-dimensional understanding of both the gray and white matter anatomy simultaneously [1, 3]. This technique, although complex and time consuming, is crucial in the formation of a proper intellectual concept about the accurate intrinsic brain anatomy and architecture. Therefore, neuroradiologists should be submitted to the aforementioned intellectual process to precisely resemble the white matter pathways of the normal and pathologic cerebrum. This is especially true since the accuracy of the entire procedure of reconstructing fiber tracts is largely dependent on the precise manual selection of the seed points. Hence, incorporating the white matter dissection technique in the basic training of neuroradiology can undoubtedly refine the results of these modern imaging studies and also enrich current knowledge about anatomofunctional brain connectivity.

Trends in the Management and Hospital Outcome of Spontaneous Subarachnoid Hemorrhage in the Post-International Subarachnoid Aneurysm Trial Era in Greece: Analysis of 719 Patients During a 13-Year Period

BACKGROUNDnManagement and outcome data on spontaneous subarachnoid hemorrhage (SAH) in Greece are scarce. We analyzed 13-year (2002-2014) retrospective data on all first-ever SAH patients referred to one of the largest neurosurgical academic departments.nnnMETHODSnPatient demographic/clinical status, length-of-hospital stay, and hospital outcome were determined. Outcome in different treatment categories was compared and prognostic factors identified.nnnRESULTSnA total of 719 patients were identified (mean age, 55 ± 12 years; men:women ratio, 1:1.4). Angiography (DSA) was performed in 88% of patients (Nxa0= 632); it was positive in 77.5% (Nxa0= 490). DSA was not performed in the remaining cases mainly due to early deaths (67 of 87; 77%). Of DSA-positive patients 74.9% (367 of 490; 51% of the total sample) underwent treatment. It comprised predominantly of coiling (81.5%) and to a lesser extent of clipping (18.5%). Lack of treatment on DSA-positive patients was largely due to early deaths (66 of 123; 53.7%). Favorable outcome was recorded in 45.6% overall (328 of 719). Favorable outcome or mean length of hospital stay did not differ significantly between coiling (51.2%; 24.7 ± 49 days) and clipping (48.8%; 28.8 ± 28 days). Nevertheless, the surgery group had a significantly higher proportion of dead patients. Advanced age and poor clinical presentation were independent risk factors for bad outcome.nnnCONCLUSIONSnPredominance of coiling over time is consistent with current trends in Western Europe and the United States. Outcome of clipping or coiling was comparable to previous salient series. Early treatment/centralization of care remain prerequisites for extending treatment options and further improving SAH outcome.

Novel case of familial normal pressure hydrocephalus

effect, as her psychosocial status was stationary. The effect of escitalopram and aripiprazole for the treatment of NSS has been individually explored. Because of the dopaminergic activating effect in the ventral tegmental area and the frontal cortex, aripiprazole plays a role in enhancing motivation. Recent research indicates that a combination of antidepressant and second-generation antipsychotic may provide a better therapeutic effect for NSS. Although escitalopram augmentation with antipsychotics showed no significant difference to placebo, the efficacy of escitalopram with an individual antipsychotic has yet to be clarified. It is generally accepted that cortical dopamine increases under 5-HT1 upregulation and 5-HT2 downregulation. Besides the D2 partial agonist effect of aripiprazole, both aripiprazole and escitalopram can be viewed as 5-HT1A receptor agonists. Escitalopram increases serotonin in the synapse, while aripiprazole is a 5-HT1A partial agonist. Therefore, the synergic effect on 5-HT1A somatodendritic autoreceptors may reduce 5-HT2A inhibition on dopaminergic neurons, then cause significant prefrontal dopamine release. This case indicates that a combination of aripiprazole and escitalopram is beneficial for NSS. The clinical improvement may take several months’ observation. Further study is needed to examine whether the regimens actually improve the daily function of simple schizophrenia.

Perioperative microdialysis in meningioma surgery: correlation of cerebral metabolites with clinical outcome

BackgroundBrain tumour resection requires surgical manoeuvres that may cause an ischaemic injury to peritumoral tissue. The aim of the present study was to examine whether putative alterations in peritumoral tissue biochemistry, monitored by microdialysis, correlate with clinical outcome in patients undergoing craniotomy for meningioma resection.MethodsIn 34 patients undergoing meningioma resection (35xa0% male; mean ageu2009±u2009SD: 54.3u2009±u200912.1xa0years), microdialysis measurements were taken perioperatively from peritumoral brain parenchyma. Standard metabolites (glucose, lactate, pyruvate, glycerol and the lactate:pyruvate ratio) were quantified in relation to clinical outcome assessed by the Glasgow Coma Scale (GCS) and the Karnofsky Performance Status scale.ResultsHigher postoperative glucose and pyruvate levels were found in patients with a favourable outcome (GCS not deteriorated or Karnofsky scoreu2009>80). Multiple logistic regression analysis (age, preoperative physical status, metabolite levels as independent variables) showed that lower postoperative glucose and pyruvate levels as well as higher lactate:pyruvate ratio values were independently associated with an unfavourable outcome as defined by Karnofsky score <80 [(OR: 0.084, 95xa0% CI: 0.01–0.98, pu2009=u20090.049), (OR: 0.97, 95xa0% CI: 0.95–0.99, pu2009=u20090.050), (OR: 1.21, 95xa0% CI: 1.04–1.42, pu2009=u20090.015) respectively], as well as with death [(OR: 0.08, 95xa0% CI: 0.01–0.97, pu2009=u20090.046), (OR: 0.94, 95xa0% CI: 0.89–0.99, pu2009=u20090.016), (OR: 1.07, 95xa0% CI: 1.00–1.15, pu2009=u20090.05) respectively].ConclusionsPostoperative levels of glucose and pyruvate and the lactate:pyruvate ratio appear to correlate with clinical outcome in patients undergoing meningioma resection. The present findings provide support for the utility of microdialysis as a prognostic tool in brain tumour surgery.

Primary cerebellar myxopapillary ependymoma

Myxopapillary ependymomas (MPEs) are slowly growing gliomas with a favorable prognosis that corresponds histologically to WHO grade I. Kernohan was the first to describe the MPE in 1931. MPEs occur almost exclusively in the conus medullaris/ cauda equina complex. However, there have been rare reports of MPEs located in other regions. Herein, we present a rare primary cerebellar intraparenchymal myxopapillary ependymoma. A 63-year-old man presented with a progressive gait unsteadiness and nausea that started 6 months prior. The medical history was unremarkable. The neurological examination on admission demonstrated truncal ataxia. He did not have any other neurological signs. Magnetic resonance imaging revealed a 3-cm welldemarcated intra-axial mass in the upper vermis (Fig. 1). The mass had an intermediate to low signal on pre-contrast T1-weighted sequences and an increased signal on T2weighted sequences. After intravenous administration of gadolinium, the mass enhanced diffusely. A Magnetic Resonance Angiography of the brain did not reveal any feeding arteries to the tumor. Metastasis is a very common cause of a posterior fossa tumor in an adult patient, consequently the patient underwent a workup which ruled-out a primary tumor outside the central nervous system. A midline suboccipital craniotomy and a small midline corticotomy in the upper vermis were performed. The lesion was covered by a thin layer of cerebellar tissue and it was noted to be grayish in color, soft and well defined. The tumor was removed in a piece-meal fashion, by the use of bipolar cautery, aspiration and ultrasonic surgical aspirator. An immediate pathology specimen was reported as a low grade neoplasm. The post-operative course was uneventful and no additional neurological deficits were noted. A brain CT scan with IV contrast did not reveal any residual enhancing tumor. Two weeks postoperatively the gait disturbance had improved, the nausea had subsided and the patient was discharged home. The Pathology laboratory reported that the tumor was a primary CNS neoplasm with histopathological and immunohistochemical characteristics consistent with myxopapillary ependymoma. More analytically the tumor characteristics were as follows: Myxoid, papillary neoplasm with microcystic formations and well demarcated by the adjacent cerebellar tissue, which was composed of cuboid cells arranged in a papillary manner around fibrovascular stromal cores. Tumor cells lacked signs of atypia or mitosis. Necrosis was absent. Immunohistochemically, the tumor cells reacted positively for GFAP and S-100 whereas immunoreactivity for cytoceratins was absent. A literature review revealed cases of spinal MPEs with brain metastasis [1]. An MRI scan of the cervical, thoracic and lumbar spine was performed to the patient and it ruled out any concurrent tumor. The patient has been followed for 1 year and his gait has been further improved. MRI scans with contrast administration at 6 months and 1 year post-operatively disclosed lack of recurrence. K. Margetis (&) C. Koutsarnakis G. Stranjalis Department of Neurosurgery, University of Athens, Evangelismos Hospital, Ipsilantou 45, 10676 Athens, Greece e-mail: konstantinmarg@yahoo.com

Parietal association deficits in patients harboring parietal lobe gliomas: a prospective study

OBJECTIVEAlthough the parietal lobe is a common site for glioma formation, current literature is scarce, consists of retrospective studies, and lacks consistency with regard to the incidence, nature, and severity of parietal association deficits (PADs). The aim of this study was to assess the characteristics and incidence of PADs in patients suffering from parietal lobe gliomas through a prospective study and a battery of comprehensive neuropsychological tests.METHODSBetween 2012 and 2016 the authors recruited 38 patients with glioma confined in the parietal lobe. Patients were examined for primary and secondary association deficits with a dedicated battery of neuropsychological tests. The PADs were grouped into 5 categories: visuospatial attention, gnosis, praxis, upper-limb coordination, and language. For descriptive analysis tumors were divided into high- and low-grade gliomas and also according to patient age and tumor size.RESULTSParietal association deficits were elicited in 80% of patients, thus being more common than primary deficits (50%). Apraxia was the most common PAD (47.4%), followed by anomic aphasia and subcomponents of Gerstmanns syndrome (34.2% each). Other deficits such as hemineglect, stereoagnosia, extinction, and visuomotor ataxia were also detected, albeit at lower rates. There was a statistically nonsignificant difference between PADs and sex (72.2% males, 85% females) and age (77.8% at ≤ 60 years, 80% at age > 60 years), but a statistically significant difference between the > 4 cm and the ≤ 4 cm diameter group (p = 0.02, 94.7% vs 63.2%, respectively). There was a tendency (p = 0.094) for low-grade gliomas to present with fewer PADs (50%) than high-grade gliomas (85.7%). Tumor laterality showed a strong correlation with hemineglect (p = 0.004, predilection for right hemisphere), anomia (p = 0.001), and Gerstmanns symptoms (p = 0.01); the last 2 deficits showed a left (dominant) hemispheric preponderance.CONCLUSIONSThis is the first study to prospectively evaluate the incidence and nature of PADs in patients with parietal gliomas. It could be that the current literature may have underestimated the true incidence of deficits. Dedicated neuropsychological examination detects a high frequency of PADs, the most common being apraxia, followed by anomia and subcomponents of Gerstmanns syndrome. Nevertheless, a direct correlation between the clinical deficit and its anatomical substrate is only possible to a limited extent, highlighting the need for intraoperative cortical and subcortical functional mapping.

The habenula in neurosurgery for depression: A convergence of functional neuroanatomy, psychiatry and imaging

BACKGROUNDnThe habenula is a small, mostly underrated structure in the pineal region. Multidisciplinary findings demonstrate an underlying complex connectivity of the habenula with the rest of the brain, subserving its major role in normal behavior and the pathophysiology of depression. These findings suggest the potential application of habenular psychosurgery in the treatment of mental disorders.nnnOBJECTIVE/HYPOTHESISnThe remission of two patients with treatment-resistant major depression treated with deep brain stimulation of the habenula supported the hypothesis that the habenula is an effective target for deep brain stimulation and initiated a surge of basic science research. This review aims to assess the viability of the deep brain stimulation of the habenula as a treatment option for treatment resistant depression.nnnMETHODSnPubMed and the Cochrane Library databases were searched with no chronological restrictions for the identification of relevant articles.nnnRESULTSnThe results of this review are presented in a narrative form describing the functional neuroanatomy of the human habenula, its implications in major depression, findings of electrode implantation of this region and findings of deep brain stimulation of the habenula for the treatment of depression.nnnCONCLUSIONnData assessing the hypothesis are scarce. Nonetheless, findings highlight the major role of the habenula in normal, as well as in pathological brain function, particularly in depression disorders. Moreover, findings of studies utilizing electrode implantation in the region of the habenula underscore our growing realization that research in neuroscience and deep brain stimulation complement each other in a reciprocal relationship; they are as self-reliant, as much as they depend on each other.

The Microsurgical Anatomy of the Orbitofrontal Arteries.

OBJECTIVEnThe orbitofrontal (or frontobasal) arteries (OFAs) are the medial (MOFA) and lateral (LOFA) orbitofrontal artery, branches of the anterior and middle cerebral artery, respectively. They supply the orbitofrontal cortex. The purpose of this microscopic cadaveric study was the detailed and precise anatomic identification of the OFAs along their course.nnnMETHODSnTwenty formalin-fixed, colored latex-injected cadaveric heads were studied with the aid of an operating microscope and microsurgical instrumentation. The anatomy of the OFAs was examined after removing the cerebrum from the cranial vault. Anatomic features of the MOFA and LOFA were investigated and assessed in relation to demographic and anthropometric variables.nnnRESULTSnThe MOFA supplies approximately 15 branches and LOFA almost 16 branches. The MOFA provides 1 branch to the olfactory bulb and 4 branches to the olfactory tract, and there are approximately 2 MOFA-LOFA anastomoses per hemisphere (novel finding). The MOFA origin is located approximately 7.9 mm anterior to the anterior communicating artery and 4.7 cm posterior to the anterior limit of the gyrus rectus. The LOFA origin is located approximately 11.1 mm from the middle cerebral artery bifurcation. Younger, shorter, and lighter individuals have more MOFA-LOFA anastomoses. Finally, the number of MOFA branches for the olfactory bulb is positively correlated with the number of MOFA branches for the olfactory tract, as well as with the number of MOFA-LOFA anastomoses.nnnCONCLUSIONSnThe present study provides a detailed description of the OFAs microsurgical anatomy and can help neurosurgeons to easily identify, manipulate, and preserve these vessels during surgery.