Relevance of intraoperative motor evoked potentials and D-wave monitoring for the resection of intramedullary spinal cord tumors in children.

The purpose of this study was to evaluate the reliability of motor evoked potentials (MEP), somatosensory evoked potentials (SSEP), and D-wave monitoring as predictors of postoperative neurological deficits in pediatric patients undergoing resection of intramedullary spinal cord tumors (IMSCTs). Additionally, we aimed to determine whether alerts in the intraoperative neurophysiological monitoring (IONM) influenced the extent of resection (EOR). A retrospective analysis of the pediatric patients who underwent resection of IMSCT between March 2010 and April 2021 with an IONM guidance was performed. IONM alerts were recorded and correlated with patients' clinical status at discharge. Twenty three pediatric patients were included. MEP and SSEP were successfully elicited in all patients, while D-wave monitoring was feasible for 14 of them (60.9%). Significant IONM alerts occurred in 6 individuals (26.1%) with monitorable MEP and SSEP and 2 patients with monitorable D-waves (14.3%). The sensitivity, specificity, positive predictive value, and negative predictive value accounted for 100%, 81.8%, 20%, 100% for MEP, 100%, 92.3%, 50%, 100% for D-wave, and 50%, 81%, 20%, 94.44% for SSEP, respectively. Both MEP (p < 0.001) and D-wave monitoring (p < 0.001) accurately predicted postoperative motor deficits, while SSEP failed to provide significant accuracy regarding sensory deficits (p = 0.491). Gross-total tumor resection was performed in 29.4% of patients without IONM alerts and 33.3% of patients with IONM alerts, indicating that IONM alerts did not limit the EOR (p = 0.0857). MEP and D-wave monitoring can be perceived as reliable IONM modalities in pediatric IMSCTs surgery. Caution is needed with the implementation of SSEP to guide surgical decisions.

Predictive Value of Motor Evoked Potentials in the Resection of Intradural Extramedullary Spinal Tumors in Children.

This study aimed to evaluate the predictive value of motor evoked potentials (MEP) in the resection of pediatric intradural extramedullary (IDEM) tumors. Additionally, we aimed to assess the impact of MEP alerts on the extent of tumor resection. Medical records of pediatric patients who underwent resection of IDEM tumors with the assistance of MEP between March 2011 and October 2020 were reviewed. The occurrence of postoperative motor deficits was correlated with intraoperative MEP alerts. Sixteen patients were included. MEP alerts appeared in 2 patients (12.5%), being reflective of new postoperative motor deficits. Among the remaining 14 patients without any intraoperative MEP alerts, no motor decline was found. Accordingly, MEP significantly predicted postoperative motor deficits, reaching sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100% (p < 0.001). In the absence of MEP alerts, 11 out of 14 patients (78.6%) underwent GTR, while no patient with intraoperative IONM alerts underwent GTR (p = 0.025). Although MEP alerts limit the extent of tumor resection, the high sensitivity and PPV of MEP underline its importance in avoiding iatrogenic motor deficits. Concurrently, high specificity and NPV ensure safer tumor excision. Therefore, MEP can reliably support surgical decisions in pediatric patients with IDEM tumors.

Multimodal Treatment of Pediatric Ruptured Brain Arteriovenous Malformations: A Single-Center Study.

Bleeding from ruptured brain arteriovenous malformations (bAVMs) represents the most prevalent cause of pediatric intracranial hemorrhage, being also the most common initial bAVM manifestation. A therapeutic approach in these patients should aim at preventing rebleeding and associated significant morbidity and mortality. The purpose of this study was to determine the clinical outcomes of pediatric patients who initially presented at our institution with ruptured bAVMs and to review our experience with a multimodality approach in the management of pediatric ruptured bAVMs. We retrospectively reviewed pediatric patients' medical records with ruptured bAVMs who underwent interventional treatment (microsurgery, embolization, or radiosurgery; solely or in combination) at our institution between 2011 and 2020. We identified 22 patients. There was no intraoperative and postoperative intervention-related mortality. Neither procedure-related complications nor rebleeding were observed after interventional treatment. Modified Rankin Scale (mRS) assessment at discharge revealed 19 patients (86.4%) with favorable outcomes (mRS 0-2) and 3 patients (13.6%) classified as disabled (mRS 3). Microsurgery ensured the complete obliteration in all patients whose postoperative digital subtraction angiography (DSA) was available. Management of high-grade bAVMs with radiosurgery or embolization can provide satisfactory outcomes without a high disability risk.

Clinical features, microbiology, and management of pediatric brainstem abscess.

PURPOSE: Brainstem abscess is a rare condition accounting for merely 1% of brain abscesses incidence in the pediatric population. This study aimed to present a single patient with a pontine abscess and review the literature to highlight clinical features, diagnosis, and management of brainstem abscess. METHODS: The PubMed database was screened for English-language articles concerning pediatric brainstem abscess. We, therefore, identified 22 publications, which concisely depict 23 cases. Our study reports on the 24th pediatric patient diagnosed with that entity. All included reports were analyzed in terms of clinical presentation, diagnosis, management, and outcomes of described patients. RESULTS: There was slight women predominance (15:9), with a mean age of occurrence 6.4 years, ranging from 7 months to 16 years. Pons was the most common location of brainstem abscess, occurring in 75% of patients. Clinically, they mostly presented with cranial nerves palsy (79.2%), hemiparesis (66.7%), and pyramidal signs (45.8%). The classic triad of symptoms, including fever, headache, and the focal neurologic deficit was present in 20.8% of patients. Positive pus cultures were obtained in 61.1%. Streptococci and Staphylococci were the most frequently identified pus microorganisms. Outcomes were satisfactory, with a 79.2% rate of general improvement. CONCLUSIONS: Neurosurgical aspiration is a safe and beneficial therapeutic method. It should always be considered and should promptly be performed when the conservative treatment is not successful and clinical deterioration occurs. Prognosis in pediatric brainstem abscess is generally favorable. Most patients recover with minor neurologic deficits or improve completely.

Small organelle, big responsibility: the role of centrosomes in development and disease.

The centrosome, a key microtubule organizing centre, is composed of centrioles, embedded in a protein-rich matrix. Centrosomes control the internal spatial organization of somatic cells, and as such contribute to cell division, cell polarity and migration. Upon exiting the cell cycle, most cell types in the human body convert their centrioles into basal bodies, which drive the assembly of primary cilia, involved in sensing and signal transduction at the cell surface. Centrosomal genes are targeted by mutations in numerous human developmental disorders, ranging from diseases exclusively affecting brain development, through global growth failure syndromes to diverse pathologies associated with ciliary malfunction. Despite our much-improved understanding of centrosome function in cellular processes, we know remarkably little of its role in the organismal context, especially in mammals. In this review, we examine how centrosome dysfunction impacts on complex physiological processes and speculate on the challenges we face when applying knowledge generated from in vitro and in vivo model systems to human development.

Loss of centrioles causes chromosomal instability in vertebrate somatic cells.

Most animal cells contain a centrosome, which comprises a pair of centrioles surrounded by an ordered pericentriolar matrix (PCM). Although the role of this organelle in organizing the mitotic spindle poles is well established, its precise contribution to cell division and cell survival remains a subject of debate. By genetically ablating key components of centriole biogenesis in chicken DT40 B cells, we generated multiple cell lines that lack centrioles. PCM components accumulated in acentriolar microtubule (MT)-organizing centers but failed to adopt a higher-order structure, as shown by three-dimensional structured illumination microscopy. Cells without centrioles exhibited both a delay in bipolar spindle assembly and a high rate of chromosomal instability. Collectively, our results expose a vital role for centrosomes in establishing a mitotic spindle geometry that facilitates correct kinetochore-MT attachments. We propose that centrosomes are essential in organisms in which rapid segregation of a large number of chromosomes needs to be attained with fidelity.

Abnormal centrosomal structure and duplication in Cep135-deficient vertebrate cells.

Centrosomes are key microtubule-organizing centers that contain a pair of centrioles, conserved cylindrical, microtubule-based structures. Centrosome duplication occurs once per cell cycle and relies on templated centriole assembly. In many animal cells this process starts with the formation of a radially symmetrical cartwheel structure. The centrosomal protein Cep135 localizes to this cartwheel, but its role in vertebrates is not well understood. Here we examine the involvement of Cep135 in centriole function by disrupting the Cep135 gene in the DT40 chicken B-cell line. DT40 cells that lack Cep135 are viable and show no major defects in centrosome composition or function, although we note a small decrease in centriole numbers and a concomitant increase in the frequency of monopolar spindles. Furthermore, electron microscopy reveals an atypical structure in the lumen of Cep135-deficient centrioles. Centrosome amplification after hydroxyurea treatment increases significantly in Cep135-deficient cells, suggesting an inhibitory role for the protein in centrosome reduplication during S-phase delay. We propose that Cep135 is required for the structural integrity of centrioles in proliferating vertebrate cells, a role that also limits centrosome amplification in S-phase-arrested cells.

Irrigation can cause prolonged intracranial pressure elevations during endoscopic treatment of intraventricular haematomas.

BACKGROUND: Irrigation may elevate the intracranial pressure (ICP) during neuroendoscopic procedures. It is unlikely that rinsing the ventricles during routine endoscopic ventriculostomy causes persistent neurological impairment or damage, but procedures such as the endoscopic evacuation of intraventricular haematomas (IVH) are performed in patients who may be prone to elevated ICP. We report a series of such patients in which we measured the ICP intraoperatively. METHOD: The charts and intraoperative ICP recording protocols of 22 patients were analysed for ICP elevations of more than 30 seconds. The measurements were performed remote from the endoscope using intraventricular catheters in 20 cases and epidural probes in 2 cases. These had been placed before the endoscopic operation for the purpose of monitoring unconscious patients or definitively diagnosing hydrocephalus. Thirteen patients suffered from intraventricular haemorrhages. Nine patients had an occlusive hydrocephalus without intraventricular blood. FINDINGS: Intraoperatively, at least one episode of ICP exceeding 30 mmHg was observed in all of the IVH patients and in seven of the remaining patients. Seven out of thirteen patients suffering from IVH exhibited more than one episode with ICP exceeding 50 mmHg, ranging from 35 up to 180 seconds. Three out of nine patients without IVH presented with such episodes, but only one of these patients presented with more than one. CONCLUSIONS: Endoscopic procedures within the cerebral ventricles are considered relatively uncomplicated procedures. However, patients undergoing treatment of IVH may suffer prolonged elevated ICP which may be critical because of their age and co-morbidity.