Evangelia Liouta, Christos Koutsarnakis, Faidon Liakos, and George Stranjalis
Current recommendations stress the need for cognitive parameters to be integrated in the evaluation of outcomes for intracranial meningioma surgery. The aim of this prospective study was to examine neurocognitive function in meningioma patients pre- and postoperatively.
Patients with skull base (anterior and middle fossa) and convexity (anterior and posterior) meningiomas (n = 54) underwent neuropsychological examination prior to and 1 year after surgery. A control group (n = 52) of healthy volunteers matched for age, sex, and education underwent the same examination. Assessments included executive, memory, and motor functions with standardized testing. Patients with convexity meningiomas were clinically assessed for parietal association cortex functions.
All patients performed significantly worse (p < 0.05) in most neurocognitive domains than controls. The skull base group showed more disturbances in memory than the convexity group (p < 0.05). The anterior convexity group showed more deficits in executive function than the posterior convexity group, which presented with parietal association cortex deficits. Verbal deficits were more pronounced in the left hemisphere than in the right hemisphere. Patients with a large tumor (> 4 cm) had more severe neurocognitive deficits than those with a small tumor (< 4 cm). Postoperatively, patients showed no deterioration in neurocognitive function. Instead, significant improvement (p < 0.05) was observed in some executive, motor, and parietal association cortex functions.
According to the authors’ findings, intracranial meningiomas may cause neurocognitive deficits in patients. Surgery does not cause a deterioration in cognitive function; instead, it may lead to improvements in some functions. Permanent neuropsychological postoperative deficits should be interpreted as tumor-induced rather than due to surgery.
Theodosis Kalamatianos, Lampis C. Stavrinou, Christos Koutsarnakis, Christina Psachoulia, Damianos E. Sakas, and George Stranjalis
A considerable body of evidence indicates that inflammation and angiogenesis play a significant role in the development and progression of chronic subdural hematoma (CSDH). While various experimental and clinical studies have implicated placental growth factor (PlGF) in the processes that underpin pathological angiogenesis, no study has thus far investigated its expression in CSDH. The actions of PlGF and its related proangiogenic vascular endothelial growth factor (VEGF) are antagonized by a high-affinity soluble receptor, namely soluble VEGF receptor–1 (sVEGFR-1), and thus the ratio between sVEGFR-1 and angiogenic factors provides an index of angiogenic capacity.
In the present study, using an automated electrochemiluminescence assay, levels of PlGF and sVEGFR-1 were quantified in serum and hematoma fluid obtained in 16 patients with CSDH.
Levels of PlGF and sVEGFR-1 were significantly higher in hematoma fluid than in serum (p < 0.0001). In serum, levels of sVEGFR-1 were higher than those of PlGF (p < 0.0001), whereas in hematoma fluid this difference was not apparent. Furthermore, the ratio of sVEGFR-1 to PlGF was significantly lower in hematoma fluid than in serum (p < 0.0001).
Given previous evidence indicating a role for PlGF in promoting angiogenesis, inflammatory cell chemotaxis, and stimulation, as well as its ability to amplify VEGF-driven signaling under conditions favoring pathological angiogenesis, enhanced expression of PlGF in hematoma fluid suggests the involvement of this factor in the mechanisms of inflammation and angiogenesis in CSDH. Furthermore, a reduced ratio of sVEGFR-1 to PlGF in hematoma fluid is consistent with the proangiogenic capacity of CSDH. Future studies are warranted to clarify the precise role of PlGF and sVEGFR-1 in CSDH.
Christos Koutsarnakis, Faidon Liakos, Evangelia Liouta, Konstantinos Themistoklis, Damianos Sakas, and George Stranjalis
The cerebral isthmus is the white matter area located between the periinsular sulcus and the lateral ventricle. Studies demonstrating the fiber tract and topographic anatomy of this entity are lacking in current neurosurgical literature. Hence, the authors’ primary aim was to describe the microsurgical white matter anatomy of the cerebral isthmus by using the fiber dissection technique, and they discuss its functional significance. In addition, they sought to investigate its possible surgical utility in approaching lesions located in or adjacent to the lateral ventricle.
This study was divided into 2 parts and included 30 formalin-fixed cerebral hemispheres, 5 of which were injected with colored silicone. In the first part, 15 uncolored specimens underwent the Klinger’s procedure and were dissected in a lateromedial direction at the level of the superior, inferior, and anterior isthmuses, and 10 were used for coronal and axial cuts. In the second part, the injected specimens were used to investigate the surgical significance of the superior isthmus in accessing the frontal horn of the lateral ventricle.
The microsurgical anatomy of the anterior, superior, and inferior cerebral isthmuses was carefully studied and recorded both in terms of topographic and fiber tract anatomy. In addition, the potential role of the proximal part of the superior isthmus as an alternative safe surgical corridor to the anterior part of the lateral ventricle was investigated.
Using the fiber dissection technique along with coronal and axial cuts in cadaveric brain specimens remains a cornerstone in the acquisition of thorough anatomical knowledge of narrow white matter areas such as the cerebral isthmus. The surgical significance of the superior isthmus in approaching the frontal horn of the lateral ventricle is stressed, but further studies must be carried out to elucidate its role in ventricular surgery.
Christos Koutsarnakis, Aristotelis V. Kalyvas, and George Stranjalis
Christos Koutsarnakis, Aristotelis V. Kalyvas, Spyridon Komaitis, Faidon Liakos, Georgios P. Skandalakis, Christos Anagnostopoulos, and George Stranjalis
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.
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.
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.
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 surgeon’s maneuverability. The authors strongly emphasize the significance of accurate anatomical knowledge.
Spyridon Komaitis, Georgios P. Skandalakis, Aristotelis V. Kalyvas, Evangelos Drosos, Evgenia Lani, John Emelifeonwu, Faidon Liakos, Maria Piagkou, Theodosis Kalamatianos, George Stranjalis, and Christos Koutsarnakis
The aim of this study was to investigate the anatomical consistency, morphology, axonal connectivity, and correlative topography of the dorsal component of the superior longitudinal fasciculus (SLF-I) since the current literature is limited and ambiguous.
Fifteen normal, adult, formalin-fixed cerebral hemispheres were studied through a medial to lateral fiber microdissection technique. In 5 specimens, the authors performed stepwise focused dissections of the lateral cerebral aspect to delineate the correlative anatomy between the SLF-I and the other two SLF subcomponents, namely the SLF-II and SLF-III.
The SLF-I was readily identified as a distinct fiber tract running within the cingulate or paracingulate gyrus and connecting the anterior cingulate cortex, the medial aspect of the superior frontal gyrus, the pre–supplementary motor area (pre-SMA), the SMA proper, the paracentral lobule, and the precuneus. With regard to the morphology of the SLF-I, two discrete segments were consistently recorded: an anterior and a posterior segment. A clear cleavage plane could be developed between the SLF-I and the cingulum, thus proving their structural integrity. Interestingly, no anatomical connection was revealed between the SLF-I and the SLF-II/SLF-III complex.
Study results provide novel and robust anatomical evidence on the topography, morphology, and subcortical architecture of the SLF-I. This fiber tract was consistently recorded as a distinct anatomical entity of the medial cerebral aspect, participating in the axonal connectivity of high-order paralimbic areas.
Evangelia Liouta, George Stranjalis, Aristotelis V. Kalyvas, Christos Koutsarnakis, Stavroula Pantinaki, Faidon Liakos, Spyros Komaitis, and Lampis C. Stavrinou
Although 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.
Between 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.
Parietal 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 Gerstmann’s 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 Gerstmann’s symptoms (p = 0.01); the last 2 deficits showed a left (dominant) hemispheric preponderance.
This 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 Gerstmann’s 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.
Abhidha Shah, Aimee Goel, Abhinandan Patil, and Atul Goel
Christos Koutsarnakis, Faidon Liakos, Aristotelis V. Kalyvas, Spyros Komaitis, and George Stranjalis
Spyridon Komaitis, Aristotelis V. Kalyvas, Georgios P. Skandalakis, Evangelos Drosos, Evgenia Lani, Evangelia Liouta, Faidon Liakos, Theodosis Kalamatianos, Maria Piagkou, John A. Emelifeonwu, George Stranjalis, and Christos Koutsarnakis
The purpose of this study was to investigate the morphology, connectivity, and correlative anatomy of the longitudinal group of fibers residing in the frontal area, which resemble the anterior extension of the superior longitudinal fasciculus (SLF) and were previously described as the frontal longitudinal system (FLS).
Fifteen normal adult formalin-fixed cerebral hemispheres collected from cadavers were studied using the Klingler microdissection technique. Lateral to medial dissections were performed in a stepwise fashion starting from the frontal area and extending to the temporoparietal regions.
The FLS was consistently identified as a fiber pathway residing just under the superficial U-fibers of the middle frontal gyrus or middle frontal sulcus (when present) and extending as far as the frontal pole. The authors were able to record two different configurations: one consisting of two distinct, parallel, longitudinal fiber chains (13% of cases), and the other consisting of a single stem of fibers (87% of cases). The fiber chains’ cortical terminations in the frontal and prefrontal area were also traced. More specifically, the FLS was always recorded to terminate in Brodmann areas 6, 46, 45, and 10 (premotor cortex, dorsolateral prefrontal cortex, pars triangularis, and frontal pole, respectively), whereas terminations in Brodmann areas 4 (primary motor cortex), 47 (pars orbitalis), and 9 were also encountered in some specimens. In relation to the SLF system, the FLS represented its anterior continuation in the majority of the hemispheres, whereas in a few cases it was recorded as a completely distinct tract. Interestingly, the FLS comprised shorter fibers that were recorded to interconnect exclusively frontal areas, thus exhibiting different fiber architecture when compared to the long fibers forming the SLF.
The current study provides consistent, focused, and robust evidence on the morphology, architecture, and correlative anatomy of the FLS. This fiber system participates in the axonal connectivity of the prefrontal-premotor cortices and allegedly subserves cognitive-motor functions. Based in the SLF hypersegmentation concept that has been advocated by previous authors, the FLS should be approached as a distinct frontal segment within the superior longitudinal system.