Faidon Liakos

Efficacy, complications and cost of surgical interventions for idiopathic intracranial hypertension: a systematic review of the literature

BackgroundTo define the efficacy, complication profile and cost of surgical options for treating idiopathic intracranial hypertension (IIH) with respect to the following endpoints: vision and headache improvement, normal CSF pressure restoration, papilloedema resolution, relapse rate, operative complications, cost of intervention and quality of life.MethodsA systematic review of the surgical treatment of IIH was carried out. Cochrane Library, MEDLINE and EMBASE databases were systematically searched from 1985 to 2014 to identify all relevant manuscripts written in English. Additional studies were identified by searching the references of retrieved papers and relative narrative reviews.ResultsForty-one (41) studies were included (36 case series and 5 case reports), totalling 728 patients. Three hundred forty-one patients were treated with optic nerve sheath fenestration (ONSF), 128 patients with lumboperitoneal shunting (LPS), 72 patients with ventriculoperitoneal shunting (VPS), 155 patients with venous sinus stenting and 32 patients with bariatric surgery. ONSF showed considerable efficacy in vision improvement, while CSF shunting had a superior headache response. Venous sinus stenting demonstrated satisfactory results in both vision and headache improvement along with the best complication profile and low relapse rate, but longer follow-up periods are needed. The complication rate of bariatric surgery was high when compared to other interventions and visual outcomes have not been reported adequately. ONSF had the lowest cost.ConclusionsNo surgical modality proved to be clearly superior to any other in IIH management. However, in certain contexts, a given approach appears more justified. Therefore, a treatment algorithm has been formulated, based on the extracted evidence of this review. The traditional treatment paradigm may need to be re-examined with sinus stenting as a first-line treatment modality.

A Laboratory Manual for Stepwise Cerebral White Matter Fiber Dissection

OBJECTIVE White 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. METHODS Twenty 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. RESULTS Eleven 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. CONCLUSIONS The 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.

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.

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.

The Superior Frontal Transsulcal Approach to the Anterior Ventricular System: Exploring the Sulcal and Subcortical Anatomy Using Anatomic Dissections and Diffusion Tensor Imaging Tractography

OBJECTIVE To explore the superior frontal sulcus (SFS) morphology, trajectory of the applied surgical corridor, and white matter bundles that are traversed during the superior frontal transsulcal transventricular approach. METHODS Twenty normal, adult, formalin-fixed cerebral hemispheres and 2 cadaveric heads were included in the study. The topography, morphology, and dimensions of the SFS were recorded in all specimens. Fourteen hemispheres were investigated through the fiber dissection technique whereas the remaining 6 were explored using coronal cuts. The cadaveric heads were used to perform the superior frontal transsulcal transventricular approach. In addition, 2 healthy volunteers underwent diffusion tensor imaging and tractography reconstruction studies. RESULTS The SFS was interrupted in 40% of the specimens studied and was always parallel to the interhemispheric fissure. The proximal 5 cm of the SFS (starting from the SFS precentral sulcus meeting point) were found to overlie the anterior ventricular system in all hemispheres. Five discrete white matter layers were identified en route to the anterior ventricular system (i.e., the arcuate fibers, the frontal aslant tract, the external capsule, internal capsule, and the callosal radiations). Diffusion tensor imaging studies confirmed the fiber tract architecture. CONCLUSIONS When feasible, the superior frontal transsulcal transventricular approach offers a safe and effective corridor to the anterior part of the lateral ventricle because it minimizes brain retraction and transgression and offers a wide and straightforward working corridor. Meticulous preoperative planning coupled with a sound microneurosurgical technique are prerequisites to perform the approach successfully.

Approaching the Atrium Through the Intraparietal Sulcus: Mapping the Sulcal Morphology and Correlating the Surgical Corridor to Underlying Fiber Tracts

BACKROUND Although the operative corridor used during the intraparietal transsulcal approach to the atrium has been previously investigated, most anatomical studies focus on its relationship to the optic radiations. OBJECTIVE To study the intraparietal sulcus (IPS) morphology and to explore the subcortical anatomy with regard to the surgical trajectory used during the intraparietal transsulcal tranventricular approach. METHODS Twenty-five adult, formalin fixed, cerebral hemispheres were investigated. Fifteen underwent the Klingler procedure and were dissected in a lateromedial direction using the fiber microdissection technique. The trajectory of the dissection resembled that of real operative settings. The remaining 10 hemispheres were cut along the longitudinal axis of the sulcus in order to correlate its surface anatomy to corresponding parts of the ventricular system. RESULTS IPS demonstrated an interrupted course in 36% of the specimens while its branching pattern was variable. The sulcus anterior half was found to overly the atrium in all occasions. Four discrete, consecutive white matter layers were identified en route to the atrium, ie, the arcuate fibers, the arcuate segment of the superior longitudinal fasciculus, the corona radiata and tapetum, with the arcuate segment being near to the dissection trajectory. CONCLUSION Given the angle of brain transgression during the intraparietal approach, we found the optimal dissection area to be the very middle of the sulcus. The IPS-postcentral sulcus meeting point, in contrast to previous thought, proved to risk potential injury to the arcuate segment of the superior longitudinal fasciculus, thus affecting surgical outcome.

Finger tapping and verbal fluency post-tap test improvement in INPH: its value in differential diagnosis and shunt-treatment outcomes prognosis

BackgroundIdiopathic normal pressure hydrocephalus (INPH) diagnosis is challenging as it can be mimicked by other neurological conditions, such as neurodegenerative dementia and motor syndromes. Additionally, outcomes after lumbar puncture (LP) tap test and shunt treatment may vary due to the lack of a common protocol in INPH assessment. The present study aimed to assess whether a post-LP test amelioration of frontal cognitive dysfunctions, characterizing this syndrome, can differentiate INPH from similar neurological conditions and whether this improvement can predict INPH post–shunt outcomes.MethodSeventy-one consecutive patients referred for INPH suspicion and LP testing, were enrolled. According to the consensus guidelines criteria, 29 patients were diagnosed as INPH and 42 were assigned an alternative diagnosis (INPH-like group) after reviewing clinical, neuropsychological and imaging data, and before LP results. A comprehensive neuropsychological assessment for frontal executive, upper extremity fine motor functions, aphasias, apraxias, agnosias and gait evaluation were administered at baseline. Executive, fine motor functions and gait were re-examined post-LP test in all patients and post-shunt placement in INPH patients.ResultsOf the INPH patients, 86.2% showed cognitive amelioration in the post-LP test; in addition, all but one (97%) presented with neurocognitive and gait improvement post-shunt. Verbal phonological fluency and finger tapping task post-LP improvement predicted positive clinical outcome post-shunt. None of the INPH-like group presented with neurocognitive improvement post-LP.ConclusionsPost-LP amelioration of verbal fluency and finger tapping deficits can differentiate INPH from similar disorders and predict positive post-shunt clinical outcome in INPH. This becomes of great importance when gait assessment is difficult to perform in clinical practice.

Defining the relationship of the optic radiation to the roof and floor of the ventricular atrium: a focused microanatomical study

Objective The authors investigated the specific topographic relationship of the optic radiation fibers to the roof and floor of the ventricular atrium because the current literature is ambiguous. Methods Thirty-five normal, adult, formalin-fixed cerebral hemispheres and 30 focused MRI slices at the level of the atrium were included in the study. The correlative anatomy of the optic radiation with regard to the atrial roof and floor was investigated in 15 specimens, each through focused fiber microdissections. The remaining 5 hemispheres were explored with particular emphasis on the trajectory of the collateral sulcus in relation to the floor of the atrium. In addition, the trajectory of the collateral sulcus was evaluated in 30 MRI scans. Results The atrial roof was observed to be devoid of optic radiations in all studied hemispheres, whereas the atrial floor was seen to harbor optic fibers on its lateral part. Moreover, the trajectory of the intraparietal sulcus, when followed, was always seen to correspond to the roof of the atrium, thus avoiding the optic pathway, whereas that of the collateral sulcus was found to lead to either the lateral atrial floor or outside the ventricle in 88% of the cases, therefore hitting the visual pathway. Conclusions Operative corridors accessing the ventricular atrium should be carefully tailored through detailed preoperative planning and effective use of intraoperative navigation to increase patient safety and enhance the surgeons maneuverability. The authors strongly emphasize the significance of accurate anatomical knowledge.

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.

Neuropsychological examination detects post-operative complications in idiopathic normal pressure hydrocephalus (iNPH): report of two cases

Subdural fluid collections (SFC) are characteristic complications of shunting for idiopathic normal pressure hydrocephalus (iNPH). This report presents two shunted iNPH patients with clinically silent postoperative SFC, detected after abnormal neuropsychological findings. These cases highlight the value of neuropsychological assessment in the routine postoperative assessment of iNPH.