'Choroid bar': easy-to-seek marker of normal posterior fossa at 12-14 weeks' gestation.

OBJECTIVES: Our objectives were: (1) to assess the visualization rate of the choroid bar in a consecutive series of 306 first-trimester scans; (2) to verify, in this cohort of fetuses, the normality of the posterior fossa later in pregnancy; and (3) to confirm the non-visualization of the choroid bar in a retrospective series of fetuses with posterior fossa malformations. METHODS: This study included a prospective and a retrospective series. The former comprised 306 fetuses undergoing routine obstetric ultrasound at our unit in both the first and second trimesters over a 6-month period, while the latter comprised 12 cases of posterior fossa malformations. In the prospective study, the presence of the choroid bar, which is defined as a visually continuous, homogeneously hyperechogenic, thick structure bridging the cisterna magna from side to side, was evaluated at the end of the first-trimester nuchal translucency scan. In the retrospective study, previously acquired three-dimensional volume datasets were processed in order to assess whether the choroid bar could be visualized in cases of open spinal dysraphisms and vermian cystic anomalies. In the prospective study, confirmation of a normal posterior fossa was based on the sonographic features of this anatomical region at the time of the second-trimester anomaly scan at 19-21 weeks' gestation, while, in the retrospective study, it was based on autopsy results, when available, or further direct imaging of the defect later in pregnancy. RESULTS: In the prospective study, the choroid bar could be visualized in all 306 fetuses, on transabdominal ultrasound in 287 (93.8%) cases and on transvaginal ultrasound in 19 (6.2%) cases. The choroid bar was displayed with a ventral/dorsal approach in 67 (21.9%) cases, with a lateral approach in 56 (18.3%) cases and with both in 183 (59.8%) cases. All 306 cases were confirmed to have a sonographically normal posterior fossa at 19-21 weeks. On the other hand, in the retrospective study, it was not possible to visualize the choroid bar in any of the fetuses with posterior fossa malformations. CONCLUSIONS: We have described a new sign, the choroid bar, consistent with a normal posterior fossa at 12-14 weeks' gestation. The choroid bar provides the option of screening for major abnormalities of the posterior fossa, since its absence raises suspicion of both open spinal dysraphisms and posterior fossa cystic malformations. At the same time, it is easy to visualize, as it can be seen with all lines of insonation. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Cerebellar mutism syndrome: the importance of preoperative language assessment.

Children undergoing surgical removal of tumors in the posterior cranial fossa can encounter a varied and complex constellation of neurological symptoms, called cerebellar mutism, defined as a disturbance in the planning and programming of motor language with preserved understanding, behavioral disorders such as inattention, visual-spatial disorganization, personality change, as well as ataxia and dysmetria. In the last years, several groups have been trying to establish risk factors or even predictive scores in order to be able at least in part to predict the appearance of speech disorders before surgery. We report on a child with pilocytic astrocytoma of the cerebellar vermis who had already been diagnosed with developmental linguistic delay two years earlier. This disorder initially worsened after surgery and later improved in the following 12 months. The aim of this paper is to emphasize the importance of preoperative neuropsychological evaluation. The present case, along with those reported in the literature, suggests that the risk of long-term cerebellar mutism is higher in children with preoperative speech disorders. In these patients a thorough assessment of cognitive and linguistic functions is therefore necessary to better evaluate the risk of cerebellar mutism after surgery.

Intramedullary spinal cord metastasis from an adenoid cystic carcinoma of the external auditory canal: case report.

BACKGROUND AND IMPORTANCE: Intramedullary spinal cord metastases (ISCMs) are rare and no cases of ISCM from an adenoid cystic carcinoma (ACC) of the external auditory canal (EAC) have been reported. CLINICAL PRESENTATION: We report a 54-year old man complaining backpain and worsening myelopathy. He had an ACC of the EAC resected years prior. A spinal MRI demonstrated a contrast-enhancing intramedullary lesion within the conus medullaris. The histopathological diagnosis of the patient was consistent with the patient's primary cancer. At 3 months follow-up, the neurological condition of the patient was unchanged. CONCLUSIONS: This is the first reported case of ISCM from a primary ACC of the EAC.

Combined circular external fixation and flexible intramedullary nailing for pediatric bilateral open tibia fractures in blast injury.

Management of blast injuries with open fractures and extensive soft tissue damage in pediatric patients is a challenging task even in experienced hands. This article reports the case of an 8-year-old boy with bilateral open tibia fractures and soft tissue loss due to the accidental explosion of a skyrocket. After the emergency procedures with lavage, debridement and temporary bone stabilization, we performed the definitive reconstruction surgery using a combined circular external fixation and flexible intramedullary nailing technique on both legs. This technique allowed easy access to the wounds for plastic surgery procedures and early bilateral weight bearing. All implants were removed within 6 months, the fractures healed with good axial alignment and the patient returned to his preinjury activities one year after the trauma. In this case, the combined use of circular external fixation and flexible intramedullary nailing ensured optimal fractures stabilization, minimizing the damage to the soft tissues and the obstruction for plastic surgeons. We believe that this technique should be considered in pediatric patients with open fractures of the lower limbs and extensive soft tissue injuries.

A snapshot of European neurosurgery December 2019 vs. March 2020: just before and during the Covid-19 pandemic.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or Covid-19), which began as an epidemic in China and spread globally as a pandemic, has necessitated resource management to meet emergency needs of Covid-19 patients and other emergent cases. We have conducted a survey to analyze caseload and measures to adapt indications for a perception of crisis. METHODS: We constructed a questionnaire to survey a snapshot of neurosurgical activity, resources, and indications during 1 week with usual activity in December 2019 and 1 week during SARS-CoV-2 pandemic in March 2020. The questionnaire was sent to 34 neurosurgical departments in Europe; 25 departments returned responses within 5 days. RESULTS: We found unexpectedly large differences in resources and indications already before the pandemic. Differences were also large in how much practice and resources changed during the pandemic. Neurosurgical beds and neuro-intensive care beds were significantly decreased from December 2019 to March 2020. The utilization of resources decreased via less demand for care of brain injuries and subarachnoid hemorrhage, postponing surgery and changed surgical indications as a method of rationing resources. Twenty departments (80%) reduced activity extensively, and the same proportion stated that they were no longer able to provide care according to legitimate medical needs. CONCLUSION: Neurosurgical centers responded swiftly and effectively to a sudden decrease of neurosurgical capacity due to relocation of resources to pandemic care. The pandemic led to rationing of neurosurgical care in 80% of responding centers. We saw a relation between resources before the pandemic and ability to uphold neurosurgical services. The observation of extensive differences of available beds provided an opportunity to show how resources that had been restricted already under normal conditions translated to rationing of care that may not be acceptable to the public of seemingly affluent European countries.

Awareness of cognitive deficits and clinical competence in mild to moderate Alzheimer's disease: their relevance in clinical practice.

Awareness of cognitive deficits and clinical competence were investigated in 79 mild to moderate Alzheimer's disease patients. Awareness was assessed by the anosognosia questionnaire for dementia, and clinical competence by specific neuropsychological tests such as trail making test-A, Babcock story recall test, semantic and phonemic verbal fluency. The findings show that 66 % of the patients were aware of memory deficits, while the 34 % were unaware. Deficit in awareness correlated with lower scores on the Mini Mental State Examination test that, in the score range from 24.51 to 30 and from 19.50 to 24.50, appeared to be a significant predictor of level of awareness. None of the AD patients had fully preserved clinical competence, only 7 patients (9 %) had partially preserved clinical competence and 72 patients (91 %) had completely lost clinical competence. All the patients with partially preserved clinical competence (9 %) were aware of their memory deficit. The study indicates that neuropsychological tests used for the assessment of executive functions are not suitable for investigating clinical competence. Therefore, additional and specific tools for the evaluation of clinical competence are necessary. Indeed, these might allow clinicians to identify AD patients who, despite their deficits in selected functions, retain their autonomy of choice as well as recognize those patients who should proceed to the nomination of a legal representative.

Neurophysiological assessment of the injured spinal cord: an intraoperative approach.

STUDY DESIGN: Prospective, observational study. OBJECTIVES: To assess the spinal cord function intraoperatively in subjects during spine stabilization for spinal cord trauma, by recording muscular (m-MEPs) and epidural motor evoked potentials (e-MEPs, D wave) along with cortical and epidural somatosensory evoked potentials (e-SEPs) and predicting the outcome of spinal cord injury (SCI). SETTING: Regional Trauma Center, Torino, Italy. METHODS: Fifty-five patients were intraoperatively studied during posterior spine stabilization surgery for traumatic SCI. In all, 21 of these had complete SCI, 14 an incomplete SCI-6 of them with central cord syndrome and 1 with central cord plus Brown Sequard syndrome-and 20 patients were neurologically uncompromised. RESULTS: The neurophysiologic profile of the complete SCI was the absence of both m-MEPs and e-MEPs caudally to the lesion site, associated with a lack of cortical and e-SEPs cranially to the lesion site. None of these patients recovered motor function in the follow-up. A clearly detectable caudal D wave was associated with motor recovery even in deeply paraparetic patients. In one neurologically incomplete patient a reversible deterioration of m-MEPs and e-MEPs was observed during the compression-distraction manoeuvre. CONCLUSION: Intraoperative neurophysiological evaluation of SCI patients can provide information about spinal cord function that is not retrievable by other clinical means and can correctly predict neurological outcome. Intraoperative testing during early stabilization of the spine of deeply paraparetic SCI patients provides additional information about their neurological profile.

A periodic charge-dipole electrostatic model. II. A kinetic-exchange-correlation correction.

We extend the periodic charge-dipole electrostatic model, see I. V. Bodrenko, M. Sierka, E. Fabiano, and F. Della Sala, J. Chem. Phys. 137, 134702 (2012), to include a kinetic-exchange-correlation (KXC) correction. The KXC correction is approximated by means of an extended-Hückel-type formula, it is exact in the infinite jellium model and it is also computationally efficient as it requires only the computation of overlap integrals. Tests on the linear response of silver slabs to an external electrostatic perturbation show that the KXC correction yields a very accurate description of induced dipole and of the whole induced charge density profile. We also show that the KXC parameters are quite transferable and related to the atomic polarizability.

Semilocal and hybrid density embedding calculations of ground-state charge-transfer complexes.

We apply the frozen density embedding method, using a full relaxation of embedded densities through a freeze-and-thaw procedure, to study the electronic structure of several benchmark ground-state charge-transfer complexes, in order to assess the merits and limitations of the approach for this class of systems. The calculations are performed using both semilocal and hybrid exchange-correlation (XC) functionals. The results show that embedding calculations using semilocal XC functionals yield rather large deviations with respect to the corresponding supermolecular calculations. Due to a large error cancellation effect, however, they can often provide a relatively good description of the electronic structure of charge-transfer complexes, in contrast to supermolecular calculations performed at the same level of theory. On the contrary, when hybrid XC functionals are employed, both embedding and supermolecular calculations agree very well with each other and with the reference benchmark results. In conclusion, for the study of ground-state charge-transfer complexes via embedding calculations hybrid XC functionals are the method of choice due to their higher reliability and superior performance.

PENG block associated with dexmedetomidine sedation for intramedullary femoral fixation in high-risk elderly patients: a case series and review of the literature.

BACKGROUND: Hip fracture is a major cause of hospitalization among the elderly population. The standard surgical treatment involves early repair to reduce mortality and morbidity. One type of treatment in the case of intertrochanteric and subtrochanteric fractures is intramedullary nailing, as it decreases soft tissue damage and permits early weight bearing. The most common anesthesia technique combines spinal anesthesia with a peripheral block. In cases where spinal anesthesia is contraindicated, general anesthesia is preferred. However, both techniques can lead to significant complications, especially in patients with multiple comorbidities. Pain management after hip surgery, particularly in elderly and frail individuals, poses a challenge. The pericapsular nerve group block (PENG) targets the innervation of the anterior portion of the hip joint and is increasingly used for pain management related to hip surgery. CASE SERIES: This paper presents a case series of three elderly patients who underwent pericapsular nerve group block (PENG) block combined with dexmedetomidine sedation for intramedullary femoral fixation. CONCLUSIONS: The PENG block can be effectively used as the sole anesthetic technique for managing elderly patients undergoing intramedullary femoral fixation while on antiplatelet drugs. This procedure effectively controlled pain during both the surgical and postoperative periods. The addition of dexmedetomidine for sedation enables comfortable and safe procedures, minimizing the risk of perioperative neurocognitive dysfunctions and without adverse effects on cardiorespiratory function.

Characterization of a new trabectedin-resistant myxoid liposarcoma cell line that shows collateral sensitivity to methylating agents.

Myxoid Liposarcomas (MLS), characterized by the expression of FUS-CHOP fusion gene are clinically very sensitive to the DNA binding antitumor agent, trabectedin. However, resistance eventually occurs, preventing disease eradication. To investigate the mechanisms of resistance, a trabectedin resistant cell line, 402-91/ET, was developed. The resistance to trabectedin was not related to the expression of MDR related proteins, uptake/efflux of trabectedin or GSH levels that were similar in parental and resistant cells. The 402-91/ET cells were hypersensitive to UV light because of a nucleotide excision repair defect: XPG complementation decreased sensitivity to UV rays, but only partially to trabectedin. 402-91/ET cells showed collateral sensitivity to temozolomide due to the lack of O(6) -methylguanine-DNA-methyltransferase (MGMT) activity, related to the hypermethylation of MGMT promoter. In 402-91 cells chromatin immunoprecipitation (ChIP) assays showed that FUS-CHOP was bound to the PTX3 and FN1 gene promoters, as previously described, and trabectedin caused FUS-CHOP detachment from DNA. Here we report that, in contrast, in 402-91/ET cells, FUS-CHOP was not bound to these promoters. Differences in the modulation of transcription of genes involved in different pathways including signal transduction, apoptosis and stress response between the two cell lines were found. Trabectedin activates the transcription of genes involved in the adipogenic-program such as c/EBPα and ß, in 402-91 but not in 402-91/ET cell lines. The collateral sensitivity of 402-91/ET to temozolomide provides the rationale to investigate the potential use of methylating agents in MLS patients resistant to trabectedin.

On the accuracy of frozen density embedding calculations with hybrid and orbital-dependent functionals for non-bonded interaction energies.

We analyze the accuracy of the frozen density embedding (FDE) method, with hybrid and orbital-dependent exchange-correlation functionals, for the calculation of the total interaction energies of weakly interacting systems. Our investigation is motivated by the fact that these approaches require, in addition to the non-additive kinetic energy approximation, also approximate non-additive exact-exchange energies. Despite this further approximation, we find that the hybrid/orbital-dependent FDE approaches can reproduce the total energies with the same accuracy (about 1 mHa) as the one of conventional semi-local functionals. In many cases, thanks to error cancellation effects, hybrid/orbital-dependent approaches yield even the smallest error. A detailed energy-decomposition investigation is presented. Finally, the Becke-exchange functional is found to reproduce accurately the non-additive exact-exchange energies also for non-equilibrium geometries. These performances are rationalized in terms of a reduced-gradient decomposition of the non-additive exchange energy.

A periodic charge-dipole electrostatic model: parametrization for silver slabs.

We present an extension of the charge-dipole model for the description of periodic systems. This periodic charge-dipole electrostatic model (PCDEM) allows one to describe the linear response of periodic structures in terms of charge- and dipole-type gaussian basis functions. The long-range electrostatic interaction is efficiently described by means of the continuous fast multipole method. As a first application, the PCDEM method is applied to describe the polarizability of silver slabs. We find that for a correct description of the polarizability of the slabs both charges and dipoles are required. However a continuum set of parametrizations, i.e., different values of the width of charge- and dipole-type gaussians, leads to an equivalent and accurate description of the slabs polarizability but a completely unphysical description of induced charge-density inside the slab. We introduced the integral squared density measure which allows one to obtain a unique parametrization which accurately describes both the polarizability and the induced density profile inside the slab. Finally the limits of the electrostatic approximations are also pointed out.

Visualization, navigation, augmentation. The ever-changing perspective of the neurosurgeon.

Introduction: The evolution of neurosurgery coincides with the evolution of visualization and navigation. Augmented reality technologies, with their ability to bring digital information into the real environment, have the potential to provide a new, revolutionary perspective to the neurosurgeon. Research question: To provide an overview on the historical and technical aspects of visualization and navigation in neurosurgery, and to provide a systematic review on augmented reality (AR) applications in neurosurgery. Material and methods: We provided an overview on the main historical milestones and technical features of visualization and navigation tools in neurosurgery. We systematically searched PubMed and Scopus databases for AR applications in neurosurgery and specifically discussed their relationship with current visualization and navigation systems, as well as main limitations. Results: The evolution of visualization in neurosurgery is embodied by four magnification systems: surgical loupes, endoscope, surgical microscope and more recently the exoscope, each presenting independent features in terms of magnification capabilities, eye-hand coordination and the possibility to implement additional functions. In regard to navigation, two independent systems have been developed: the frame-based and the frame-less systems. The most frequent application setting for AR is brain surgery (71.6%), specifically neuro-oncology (36.2%) and microscope-based (29.2%), even though in the majority of cases AR applications presented their own visualization supports (66%). Discussion and conclusions: The evolution of visualization and navigation in neurosurgery allowed for the development of more precise instruments; the development and clinical validation of AR applications, have the potential to be the next breakthrough, making surgeries safer, as well as improving surgical experience and reducing costs.

Degenerative cervical myelopathy: Neuroradiological, neurophysiological and clinical correlations in 27 consecutive cases.

•New insight into prognostic factors for recovery of clinical function following posterior decompression for degenerative cervical myelopathy.•An increase of IOM amplitude of at least 50% coupled with preoperative T2-only and diffuse T2 signal changes on MRI is a positive prognostic factors for clinical improvement 6 months after surgery.•Clinical improvement at 6 months follow-up can be expected in patients with T1 hypo intensity if a diffuse border of the lesion on T2 images is present.

Electrostatic-field-driven alignment of organic oligomers on ZnO surfaces.

We study the physisorption of organic oligomers on the strongly ionic ZnO(1010) surface by using first-principles density-functional theory and nonempirical embedding methods. It turns out that the in-plane variation of the molecule-substrate interaction energy and the bonding dipole in the vertical direction are linked up by a linear relationship originating from the electrostatic coupling of the molecule with the periodic dipolar electric field generated by the Zn-O surface dimers. Long oligomers with a highly axial π-electron system such as sexiphenyl become well oriented with alignment energies of several 100 meV along rows of a positive electric field, in full agreement with recent experiments. These findings define a new route towards the realization of highly ordered self-assembled arrays of oligomers or polymers on ZnO(1010) and similar surfaces.

Semiclassical neutral atom as a reference system in density functional theory.

We use the asymptotic expansions of the semiclassical neutral atom as a reference system in density functional theory to construct accurate generalized gradient approximations (GGAs) for the exchange-correlation and kinetic energies without any empiricism. These asymptotic functionals are among the most accurate GGAs for molecular systems, perform well for solid state, and overcome current GGA state of the art in frozen density embedding calculations. Our results also provide evidence for the conjointness conjecture between exchange and kinetic energies of atomic systems.

Exchange-correlation generalized gradient approximation for gold nanostructures.

We compare the performance of different exchange-correlation functionals, based on the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation, for the structural and electronic properties of gold nanostructures. In particular we consider PBEsol (constructed to correctly describe solid-state systems) and PBEint [Phys. Rev. B 82, 113104 (2010)] which was recently introduced for hybrid interfaces and preserves the correct second-order gradient expansion of exchange energy (as in PBEsol) providing as well a significant nonlocality for higher density variation (as in PBE). We find that the PBEint functional gives a well balanced description of atomization energies, structural properties, energy differences between isomers, and bulk properties. Results indicate that PBEint is expected to be the most accurate functional for medium and large size gold clusters of different shapes.

Latency time in cutaneous leishmaniasis.

Latency period in cutaneous leishmaniasis was very rarely studied so far. We describe three patients, aged 71, 50 and 32 years, respectively, who contracted cutaneous leishmaniasis in Sicily. In all patients, clinical diagnosis was confirmed by histopathological examination and polymerase chain reaction: the latter was positive for Leishmania infantum in two patients and Leishmania canis in one. All cases were characterized by a very long period of latency, ranging from 11 to 16 months. These cases suggest that latency time of cutaneous leishmaniasis acquired in Sicily may be sometimes very long. The reasons of this latency time are unknown: latency depends neither by the involved species of sandflies and Leishmania nor by the immunological response of the patients: all laboratory tests, including immunological ones, were normal.