Vascular complications in craniopharyngioma-resected paediatric patients: a single-center experience.

Background: Craniopharyngioma (CP), although slow growing and histologically benign, has high morbidity, mostly related to hypothalamus-pituitary dysfunction and electrolyte imbalance. Increased risk of vascular complications has been described. However, data are still poor, especially in the paediatric population. The aim of our study was to evaluate the occurrence, timing, and predisposing factors of deep venous thrombosis (DVT) and other vascular alterations in neurosurgical paediatric CP patients. Materials and Methods: In a single-centre, retrospective study, we investigated 19 CP patients (11 males, 8 females, mean age 10.5 ± 4.3 years), who underwent neurosurgery between December 2016 and August 2022, referred to Meyer Children's Hospital IRCCS in Florence. Results: Five patients (26.3%) presented vascular events, which all occurred in connection with sodium imbalances. Three DVT (two with associated pulmonary embolism, in one case leading to death) developed in the post-operative period, most frequently at 7-10 days. Elevated D-dimers, a reduced partial activated thrombin time and a prolonged C-reactive protein increase were highly related to thrombotic vascular events. One case of posterior cerebral artery pseudoaneurysm was described soon after neurosurgery, requiring vascular stenting. Superficial vein thrombophlebitis was a late complication in one patient with other predisposing factors. Conclusion: CP patients undergoing neurosurgery are at risk of developing DVT and vascular alterations, thus careful follow-up is mandatory. In our study, we found that the phase of transition from central diabetes insipidus to a syndrome of inappropriate antidiuretic hormone secretion may be a period of significant risk for DVT occurrence. Careful vascular follow-up is mandatory in CP-operated patients.

Paediatric endoscopic endonasal middle skull base reconstruction: retrospective analysis of 78 patients treated in a single tertiary care paediatric center.

INTRODUCTION: Skull base pathologies in the paediatric population are rare and require treatment by multiple qualified specialists. The endoscopic endonasal approach has revolutionized surgical treatment because it is less invasive than existing treatments.The goal of this study was to retrospectively review our experience with the reconstruction of paediatric skull middle base defects and associated complications. MATERIALS AND METHODS: We analysed medical records from patients aged ≤ 18 years who were treated at our centre between 2013 and 2021. Patients treated with an endoscopic skull base approach and reconstruction, and who had complete clinical and radiological documentation and a minimum follow-up of 12 months, were included in the analysis. Personal data, reconstructive techniques, and complications were analysed. RESULTS: A total of 78 patients met the inclusion criteria and were enrolled in the study. Of these patients, 32 were male and 46 were female, and the mean age was 11.5 years. The main signs and symptoms were as follows: bitemporal hemianopsia in 53 cases, visual impairment in 23 cases, and headache in 30 cases. The most frequent aetiologies were craniopharyngioma (38 cases), pituitary adenoma (23 cases), and clivus chordoma (4 cases). All patients were treated via a pure endoscopic approach. For reconstruction, a multilayer technique was used in 18 cases, naso-septal flap in 43 cases, Gasket-Seal technique in 12 cases, and heterologous reconstruction in 5 cases. Only six patients presented a major complication: two had a postoperative cerebral spinal fluid leak, one developed a brain abscess, and three had diabetes insipidus.The mean follow-up period was 23.4 months.There were no statistically significant differences in postoperative CSF leak in relation to different reconstructive techniques. CONCLUSION: Endoscopic endonasal skull base surgery is a safe and effective treatment for paediatric middle skull base pathologies. Reconstruction techniques have a high success rate of 96.5-100%, and the rate of associated complications is < 3%.

Leat-associated seizures the possible role of EAAT2, pyruvate carboxylase and glutamine synthetase.

BACKGROUND: Drug-resistant epilepsy is a common condition in patients with brain neoplasms. The pathogenesis of tumor-associated seizures is poorly understood. Among the possible pathogenetic mechanisms, the increase in glutamate concentration has been proposed. Glutamate transporters, glutamine synthetase and pyruvate carboxylase are involved in maintaining the physiological concentration of glutamate in the intersynaptic spaces. In our previous research on angiocentric gliomas, we demonstrated that all tumors lacked the expression of the main glutamate transporter EAAT2, while the expression of glutamine synthetase and pyruvate carboxylase was mostly preserved. METHODS: In the present study, we evaluated the immunohistochemical expression of EAAT2, glutamine synthetase and pyruvate carboxylase in a heterogeneous series of 25 long-term epilepsy-associated tumors (10 dysembryoplastic neuroepithelial tumors, 7 gangliogliomas, 3 subependymal giant cell astrocytomas, 3 rosette forming glioneuronal tumors, 1 diffuse astrocytoma MYB- or MYBL1-altered and 1 angiocentric glioma). In order to evaluate the incidence of variants in the SLC1A2 gene, encoding EAAT2, in a large number of central nervous system tumors we also queried the PedcBioPortal. RESULTS: EAAT2 protein expression was lost in 9 tumors (36 %: 3 dysembryoplastic neuroepithelial tumors, 1 ganglioglioma, 3 subependymal giant cell astrocytomas, 1 diffuse astrocytoma MYB- or MYBL1-altered and 1 angiocentric glioma). Glutamine synthetase protein expression was completely lost in 2 tumors (8 %; 1 ganglioglioma and 1 diffuse astrocytoma MYB- or MYBL1-altered). All tumors of our series but rosette forming glioneuronal tumors (in which neurocytic cells were negative) were diffusely positive for pyruvate carboxylase. Consultation of the PedcBioPortal revealed that of 2307 pediatric brain tumors of different histotype and grade, 20 (< 1%) had variants in the SLC1A2 gene. Among the SLC1A2-mutated tumors, there were no angiocentric gliomas or other LEATs CONCLUSIONS: In conclusion, unlike angiocentric gliomas where the EAAT2 loss is typical and constant, the current study shows the loss of EAAT2 expression only in a fraction of the LEATs. In these cases, we may hypothesize some possible epileptogenic role of the EAAT2 loss. The retained expression of pyruvate carboxylase may contribute to determining a pathological glutamate excess unopposed by glutamine synthetase that resulted expressed to a variable extent in the majority of the tumors. Furthermore, we can assume that the EAAT2 loss in brain tumors in general and in LEATs in particular is more conceivably epigenetic.

HyM3D: A hybrid method for the automatic 3D reconstruction of a defective cranial vault.

BACKGROUND AND OBJECTIVE: The ability to accomplish a consistent restoration of a missing or deformed anatomical area is a fundamental step for defining a custom implant, especially in the maxillofacial and cranial reconstruction where the aesthetical aspect is crucial for a successful surgical outcome. At the same time, this task is also the most difficult, time-consuming, and complicated across the whole reconstruction process. This is mostly due to the high geometric complexity of the anatomical structures, insufficient references, and significant interindividual anatomical heterogeneity. Numerous solutions, specifically for the neurocranium, have been put forward in the scientific literature to address the reconstruction issue, but none of them has yet been persuasive enough to guarantee an easily automatable approach with a consistent shape reconstruction. METHODS: This work aims to present a novel reconstruction method (named HyM3D) for the automatic restoration of the exocranial surface by ensuring both the symmetry of the resulting skull and the continuity between the reconstructive patch and the surrounding bone. To achieve this goal, the strengths of the Template-based methods are exploited to provide knowledge of the missing or deformed region and to guide a subsequent Surface Interpolation-based algorithm. HyM3D is an improved version of a methodology presented by the authors in a previous publication for the restoration of unilateral defects. Differently from the first version, the novel procedure applies to all kinds of cranial defects, whether they are unilateral or not. RESULTS: The presented method has been tested on several test cases, both synthetic and real, and the results show that it is reliable and trustworthy, providing a consistent outcome with no user intervention even when dealing with complex defects. CONCLUSIONS: HyM3D method proved to be a valid alternative to the existing approaches for the digital reconstruction of a defective cranial vault; furthermore, with respect to the current alternatives, it demands less user interaction since the method is landmarks-independent and does not require any patch adaptation.

Is endoscope-assisted strip craniectomy the future of metopic suture craniosynostosis treatment? An 11-year experience with 62 patients.

OBJECTIVE: Endoscopic mini-invasive treatment for sporadic trigonocephaly is becoming a widely accepted surgical treatment. In most centers this treatment is performed in association with postoperative helmeting. The aim of the present study was to review and report the authors' 11-year experience of endoscope-assisted metopic suturectomy for treatment of 62 trigonocephaly patients without helmet use. METHODS: For this retrospective study, clinical data of 62 consecutive pediatric patients (age 3-8 months) were obtained from the data bank of the "Anna Meyer" Children Hospital. These patients had been diagnosed with trigonocephaly (type II and III) and undergone surgery performed with a mini-invasive endoscopic technique during the period from January 2011 to January 2022. No helmet was used postoperatively in these patients, and they were evaluated through craniometric measurements, pre-/postoperative photographs, and parents' impressions, as well as thorough clinical examinations during follow-up appointments. RESULTS: The mean patient follow-up period was 6 ± 1.3 years. The female/male ratio was 1:2; 52% of the patients presented with type II trigonocephaly and the remaining patients with type III. The mean age at surgery was 153 ± 44 days (5 ± 1.5 months, range 3-8 months). In 92% of the patients the surgical outcome was defined as good to excellent. However, 4 patients presented with an unsatisfactory outcome, including 1 patient with a CSF collection requiring surgical repair 2 months after the first surgery and 1 patient who developed infection of the surgical wound and needed a second surgery. In the latter patient the outcome was evaluated as satisfactory, and no sequelae regarding the infection were encountered during follow-up. CONCLUSIONS: According to the authors' experience, endoscopic metopic suturectomy alone, without the use of a helmet, is a valid surgical option for trigonocephaly treatment, and its application can be considered in patients of older age groups (up to 8 months). Thus, in the right patient selection context, this technique represents the treatment of choice.

Endoscopic Endonasal Treatment of Intra-Axial Ventral Brainstem Cavernomas: Case Experience and Literature Review.

INTRODUCTION: Cavernous malformations of the ventral brainstem are a challenging disease to treat. From an anatomical perspective, the best surgical options are endoscopic endonasal approaches. The first reports of their usage for this purpose date back to 2012. In this study, we gathered data on the subject, share our experience, and outline technical notes and tips for this surgery. CASE PRESENTATION: We report a 14-year-old female with a ventral pons cavernoma, treated using an endoscopic endonasal transclival approach and followed-up for 5.9 years. This is the longest reported follow-up for this condition to date. Written informed consent was obtained from the patient for publication of this case report and the accompanying images. DISCUSSION: An endoscopic endonasal transclival approach was used. The skull base was reconstructed using the multilayer grafting technique and a nasoseptal flap. There was no postoperative cerebrospinal fluid leakage. In a literature review, we identified 8 patients who were treated endoscopically: 1 transplanum-transtuberculum, 1 transtuberculum-transclival, and 6 transclival approaches were employed. Skull base closure was achieved using multilayer grafting and a nasoseptal flap in 4 cases, a gasket seal technique combined with nasoseptal flap in 3 cases and a periumbilical fat graft, fibrin sealant patch, and fibrin glue in 1 case. There were 2 cases of leakage, which resolved completely with revision surgery. CONCLUSION: Endoscopic surgery is a reliable alternative to traditional open surgery. It may be the preferred choice for intra-axial ventral brain cavernomas.

Dysembryoplastic neuroepithelial tumors: A single-institutional series with special reference to glutamine synthetase expression.

Dysembryoplastic neuroepithelial tumors (DNT) is a benign (World Health Organisation, WHO, grade I) glioneuronal tumor and it represent one of the most frequent neoplasm in patient affected by seizures. The epileptic neuronal activity can be determined by abnormal synchronization, excessive glutamate excitation and\or inadequate GABA inhibition. Increasing evidence suggests that the astrocytes might be involved in this process even if neurons play a relevant role. In particular astrocytes promote the clearance of glutamate, a potent excitatory neurotransmitter of the central nervous system. Indeed, elevated concentrations of extracellular glutamate may determine iper-excitability and seizures as well as other neurological disorders. So, astrocytes, converting glutamate into glutamine via the enzyme glutamine synthetase (GS), could play a protective anti-seizures role. In the present study, we analyzed the immunohistochemical expression of GS in 20 DNTs specimens documenting a constant immunoistochemical expression of GS in astrocytes of the lesional tissue and of the cerebral cortex.

Angiocentric glioma-associated seizures: The possible role of EATT2, pyruvate carboxylase and glutamine synthetase.

PURPOSE: Our purpose was to better understand the pathogenesis of seizures associated with angiocentric glioma. Angiocentric glioma is an indolent and rare low-grade glioma. Its typical clinical presentation is with epileptic seizures. The pathogenesis of tumor-associated seizures is poorly understood. Among the possible pathomechanisms, the increased neurotoxic concentrations of the glutamate has been proposed. Glutamate transporters, pyruvate carboxylase and glutamine synthetase are involved in maintaining the physiological concentration of glutamate in the inter synaptic spaces. METHODS: We evaluated the immunohistochemical expression of EAAT2 (the most important glutamate transporter), pyruvate carboxylase and glutamine synthetase in 17 angiocentric gliomas. RESULTS: EAAT2 was never expressed (0%) in the neoplastic cells in none of the cases studied. Pyruvate carboxylase was expressed in the cytoplasm of the neoplastic cells in 16/17 cases (94 %). Glutamine synthetase was expressed in the cytoplasm of the neoplastic cells in 15/17 cases (88 %). CONCLUSION: The net result of this enzymatic expression, in particular considering the loss of EAAT2, could be an increased glutamate concentration in the synaptic clef, which might increase local network excitability initially involving intratumoral neurons. The observation that the angiocentric glioma-associated epilepsy might be at least in part related to EAAT2 deficiency opens up interesting therapeutic perspectives.

Neonatal Cerebellar Hemorrhage and Facial Nerve Palsy: An Unusual Association.

Cerebellar hemorrhage is rare in term newborns and is most often seen after traumatic birth. Lifelong sequelae include motor and cognitive impairment. We report the uncommon case of a late preterm infant born by spontaneous delivery who showed right peripheral facial palsy at 24 hours of life. Cranial ultrasound showed lateral ventricles dilatation and a diffuse hyperechoic round lesion in the right cerebellar hemisphere. The computed tomography scan confirmed a hemorrhagic lesion in the right cerebellar hemisphere and in the vermis with midline shift and intraventricular bleeding. Ommaya reservoir was inserted and used for a few days. The facial palsy gradually recovered to a complete remission after 6 weeks. Follow-up examinations at 12 and 18 months evidenced infant's delayed motor function, hyperreflexia, tremors, and speech delay.

Current Practice in Preoperative Virtual and Physical Simulation in Neurosurgery.

In brain tumor surgery, an appropriate and careful surgical planning process is crucial for surgeons and can determine the success or failure of the surgery. A deep comprehension of spatial relationships between tumor borders and surrounding healthy tissues enables accurate surgical planning that leads to the identification of the optimal and patient-specific surgical strategy. A physical replica of the region of interest is a valuable aid for preoperative planning and simulation, allowing the physician to directly handle the patient's anatomy and easily study the volumes involved in the surgery. In the literature, different anatomical models, produced with 3D technologies, are reported and several methodologies were proposed. Many of them share the idea that the employment of 3D printing technologies to produce anatomical models can be introduced into standard clinical practice since 3D printing is now considered to be a mature technology. Therefore, the main aim of the paper is to take into account the literature best practices and to describe the current workflow and methodology used to standardize the pre-operative virtual and physical simulation in neurosurgery. The main aim is also to introduce these practices and standards to neurosurgeons and clinical engineers interested in learning and implementing cost-effective in-house preoperative surgical planning processes. To assess the validity of the proposed scheme, four clinical cases of preoperative planning of brain cancer surgery are reported and discussed. Our preliminary results showed that the proposed methodology can be applied effectively in the neurosurgical clinical practice both in terms of affordability and in terms of simulation realism and efficacy.

Erratum: Neonatal Cerebellar Hemorrhage and Facial Nerve Palsy: An Unusual Association.

[This corrects the article DOI: 10.1055/s-0040-1715162.][This corrects the article DOI: 10.1055/s-0040-1715162.].

A Diagnostic Pitfall: Atypical Teratoid Rhabdoid Tumor Versus Dedifferentiated/Poorly Differentiated Chordoma: Analysis of a Mono-institutional Series.

Atypical teratoid/rhabdoid tumor (AT/RT) and dedifferentiated/poorly differentiated chordoma are pediatric tumors with some overlapping morphologic, immunohistochemical, and molecular features. Both these tumors have alterations in the tumor suppressor gene SMARCB1 resulting in loss of expression of the INI-1 protein. On the contrary, dedifferentiated/poorly differentiated chordoma expresses the transcription factor brachyury, whereas AT/RT does not. In this article we have reviewed the clinicopathologic features of a pediatric series of tumors (17 samples from 14 patients) located in the brain or within the axial spine and the base of the skull diagnosed as AT/RTs or as dedifferentiated/poorly differentiated chordomas. On the basis of the INI-1 and brachyury immunohistochemical results we reevaluated the initial diagnoses. Four misdiagnoses were revised. The differential diagnosis between AT/RT and dedifferentiated/poorly differentiated chordoma or on occasion medulloblastoma may be difficult. The use of 2 antibodies, INI-1, and brachyury, may be the key for the right diagnosis.

Endoscopic endonasal skull base surgery in pediatric patients. A single center experience.

OBJECT: At present, a minimally invasive endoscopic endonasal approach is considered an efficient option for lesions affecting the anterior and middle skull base with sellar and parasellar region involvement. In this study we will retrospectively analyze the pediatric patients that we have been treating in the same medical center for the past four years, using an endoscopic approach in the skull base. METHODS: We performed a retrospective chart and imaging review of pediatric patients who underwent endoscopic endonasal skull base surgery (ESBS) at the Meyer Children's Hospital, (Azienda Ospedaliero Universitaria Meyer), in Florence, from January 2012 to July 2016. RESULTS: Mean age was 12,5 years; 28 (65%) of the 44 patients were females. Skull base lesions were broadly classified as either bony abnormalities (4 cases) or skull base tumors (40 cases). The postoperative clinical follow-up duration ranged from 2 to 36 months. The two more frequently occurring diseases in our study were: craniopharyngioma and pituitary adenoma. CONCLUSIONS: After reviewing the international literature about pediatric endoscopic endonasal approach to skull base, we can affirm that our study is the world's second broadest work for number of records. While compiling this report, we have examined the first 40 consecutive pediatric patients to undergo ESBS at our institute. The appearance of postoperative complications is consistent with other international studies, confirming ESBS being feasible and safe even in the pediatric population. LEVEL OF EVIDENCE: 4.

Surgery of complex craniofacial defects: A single-step AM-based methodology.

BACKGROUND AND OBJECTIVE: The purpose of the present paper is to pave the road to the systematic optimization of complex craniofacial surgical intervention and to validate a design methodology for the virtual surgery and the fabrication of cranium vault custom plates. Recent advances in the field of medical imaging, image processing and additive manufacturing (AM) have led to new insights in several medical applications. The engineered combination of medical actions and 3D processing steps, foster the optimization of the intervention in terms of operative time and number of sessions needed. Complex craniofacial surgical intervention, such as for instance severe hypertelorism accompanied by skull holes, traditionally requires a first surgery to correctly "resize" the patient cranium and a second surgical session to implant a customized 3D printed prosthesis. Between the two surgical interventions, medical imaging needs to be carried out to aid the design the skull plate. Instead, this paper proposes a CAD/AM-based one-in-all design methodology allowing the surgeons to perform, in a single surgical intervention, both skull correction and implantation. METHODS: A strategy envisaging a virtual/mock surgery on a CAD/AM model of the patient cranium so as to plan the surgery and to design the final shape of the cranium plaque is proposed. The procedure relies on patient imaging, 3D geometry reconstruction of the defective skull, virtual planning and mock surgery to determine the hypothetical anatomic 3D model and, finally, to skull plate design and 3D printing. RESULTS: The methodology has been tested on a complex case study. Results demonstrate the feasibility of the proposed approach and a consistent reduction of time and overall cost of the surgery, not to mention the huge benefits on the patient that is subjected to a single surgical operation. CONCLUSIONS: Despite a number of AM-based methodologies have been proposed for designing cranial implants or to correct orbital hypertelorism, to the best of the authors' knowledge, the present work is the first to simultaneously treat osteotomy and titanium cranium plaque.

Spinal cord involvement in two children with posterior reversible encephalopathy syndrome.

Spinal cord involvement (SCI) is a rare feature of posterior reversible encephalopathy syndrome (PRES), especially in children. SCI is generally symptomatic, and may have a different outcome compared with encephalic localization of PRES. We reported about two cases of SCI in pediatric patients with PRES, after multimodal anticancer therapies, including radiotherapy, chemotherapy and targeted agents.

Subependymal giant cell astrocytoma: a lesion with activated mTOR pathway and constant expression of glutamine synthetase.

Subependymal giant-cell astrocytoma (SEGA) is a rare tumor associated with tuberous sclerosis complex (TSC). TSC mainly involves the central nervous system (CNS) where SEGA, subependymal nodules, and cortical tubers may be present. First studies suggested the astrocytic nature of SEGA while successive studies demonstrated the mixed glio-neuronal nature. There are similarities between TSC-associated CNS lesions and type IIb focal cortical dysplasia (FCD). In all these pathologies, mammalian target of rapamycin (mTOR) pathway activation has been demonstrated. Recent data evidenced that balloon cells in FCD IIb express glutamine synthetase (GS). GS is involved in the clearance of glutamate. Cells expressing GS might exert an antiepileptic role. We evaluated by immunohistochemistry the glial fibrillary acidic protein (GFAP), neurofilaments (NF), and GS expression and the mTOR status (mTOR and phosphorylated ribosomal protein S6) in 16 SEGAs and 2 cortical tubers. Our purpose was to emphasize the mixed nature of SEGA and to further investigate the similarities between TSC-related CNS lesions (in particular SEGA) and FCD IIb. We confirm the glio-neuronal nature and the common activation of the mTOR pathway in SEGAs. In addition, we report for the first time that these tumors, analogously to FCD IIb, commonly express GS. Notably, the expression of mTOR, phosphorylated ribosomal protein S6, and GS was restricted to gemistocytic-like GFAP-negative cells. GS expression and mTOR pathway activation were also documented in cortical tubers. Further studies are necessary to understand the significance of GS expression in SEGAs as well as in cortical tubers.