Polarimetric imaging for the detection of synthetic models of SARS-CoV-2: A proof of concept.

Objective: To conduct a proof-of-concept study of the detection of two synthetic models of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using polarimetric imaging. Approach: Two SARS-CoV-2 models were prepared as engineered lentiviruses pseudotyped with the G protein of the vesicular stomatitis virus, and with the characteristic Spike protein of SARS-CoV-2. Samples were prepared in two biofluids (saline solution and artificial saliva), in four concentrations, and deposited as 5-µL droplets on a supporting plate. The angles of maximal degree of linear polarization (DLP) of light diffusely scattered from dry residues were determined using Mueller polarimetry from87 samples at 405 nm and 514 nm. A polarimetric camera was used for imaging several samples under 380-420 nm illumination at angles similar to those of maximal DLP. Per-pixel image analysis included quantification and combination of polarization feature descriptors in 475 samples. Main results: The angles (from sample surface) of maximal DLP were 3° for 405 nm and 6° for 514 nm. Similar viral particles that differed only in the characteristic spike protein of the SARS-CoV-2, their corresponding negative controls, fluids, and the sample holder were discerned at 10-degree and 15-degree configurations. Significance: Polarimetric imaging in the visible spectrum may help improve fast, non-contact detection and identification of viral particles, and/or other microbes such as tuberculosis, in multiple dry fluid samples simultaneously, particularly when combined with other imaging modalities. Further analysis including realistic concentrations of real SARS-CoV-2 viral particles in relevant human fluids is required. Polarimetric imaging under visible light may contribute to a fast, cost-effective screening of SARS-CoV-2 and other pathogens when combined with other imaging modalities.

Presigmoid approach preserving the superior petrosal sinus in a pontine cavernous malformation associated to abnormal venous drainage of the brainstem: how I do it.

BACKGROUND: The presigmoid approach classically includes the ligature and section of the superior petrosal sinus to get a wider visibility window to the antero-lateral brainstem surface. In some cases, the separation of this venous structure should not be performed. METHOD: We present our experience getting safely to a pontine cavernous malformation through a conventional mastoidectomy presigmoid approach preserving an ingurgitated superior petrosal sinus because the association with an abnormal venous drainage of the brainstem. CONCLUSIONS: When sectioning the superior petrosal sinus in classical presigmoid approaches is contraindicated, its preservation could also offer good surgical corridors to get to small-medium anterior and lateral brainstem cavernous malformations.

Intracranial leptomeningeal CNS ganglioneuroblastoma. First report and review of the literature.

BACKGROUND: CNS ganglioneuroblastoma in an extremely rare embryonal tumour, specifically in the pediatric population. Bad prognosis is documented due to aggressiveness and absence of protocolized treatment at the moment. CLINICAL DESCRIPTION: We present the case of a 5-year-old boy who presented with sudden loss of consciousness. CT scan was performed showing a large posterior fossa lesion with several intraventricular focal lesions, suggesting metastases, the largest one located inside the III ventricle. The patient underwent a posterior fossa resection of the lesion and a subtotal resection of the III ventricle lesion, with adjuvant chemotherapy. The evolution was poor and the patient finally died 3 months after diagnosis. CONCLUSION: Ganglioneuroblastoma is extremely likely to recur quickly and extensively. There is little knowledge about treatment options but is documented that gross total resection followed by adjuvant radiotherapy and chemotherapy is the best management in these patients.

Posterolateral trans dentate approach to anterior extensive extramedullary tumor of the cervical spine in a pediatric case: how I do it.

BACKGROUND: Extramedullary anterior cervical canal tumors can be challenging lesions to reach. The posterolateral trans dentate approach offers an alternative route. METHOD: Classic posterior laminoplasty is done to expose the medulla; the dentate ligament is identified as a fibrous structure running from the lateral pial surface of the medulla to the lateral dura between nerve roots spaces. Once the ligament is cut, the medulla can be gently rotated to access the anterior cervical canal. Intraoperative neurophysiological stimulation is mandatory. CONCLUSION: This approach allows a safe route, without the need for corpectomies. It should be considered especially in children where multilevel corpectomies could be challenging.

Bilateral chiasm and optic nerve micro-decompression in a child with extensive cranial fibrous dysplasia: how I do it.

BACKGROUND: Surgical decompression to the optic-chiasmatic region in craneofacial fibrous dysplasia (CFD) must be performed safely to improve or stabilize visual loss. METHOD: We describe a technical nuance when facing on a huge, deformed skull with potentially imbricated dura mater. Craniectomy was performed in concentric arches allowing to expose surgical field and elevated step by step. Bilateral micro-decompression was performed after without difficulties. CONCLUSIONS: Decompressing both optic nerves using this technique is safe and relatively simple to perform.

The non-canonical Wnt-PCP pathway shapes the mouse caudal neural plate.

The last stage of neural tube (NT) formation involves closure of the caudal neural plate (NP), an embryonic structure formed by neuromesodermal progenitors and newly differentiated cells that becomes incorporated into the NT. Here, we show in mouse that, as cell specification progresses, neuromesodermal progenitors and their progeny undergo significant changes in shape prior to their incorporation into the NT. The caudo-rostral progression towards differentiation is coupled to a gradual reliance on a unique combination of complex mechanisms that drive tissue folding, involving pulses of apical actomyosin contraction and planar polarised cell rearrangements, all of which are regulated by the Wnt-PCP pathway. Indeed, when this pathway is disrupted, either chemically or genetically, the polarisation and morphology of cells within the entire caudal NP is disturbed, producing delays in NT closure. The most severe disruptions of this pathway prevent caudal NT closure and result in spina bifida. In addition, a decrease in Vangl2 gene dosage also appears to promote more rapid progression towards a neural fate, but not the specification of more neural cells.

Cranial expansion and aqueductoplasty for combined isolated fourth ventricle and slit-ventricle syndrome: a surgical alternative.

INTRODUCTION: An isolated fourth ventricle (IFV) is a rare entity observed in shunted patients and its treatment is still uncertain. Endoscopic aqueductoplasty has shown good results for restoring CSF flux between the third and fourth ventricles. However, it needs some grade of ventricular dilation to be performed. Some patients affected by IFV show slit-ventricle morphology in CT/MRI. Usually, the rise of opening pressure or the shunt externalization gets enough ventricular dilation. However, the lack of intracranial compliance in some patients makes these options unsuitable and high-ICP symptoms are developed without ventricular dilation. METHODS: We present a two cases series affected by IFV with no ventricular dilation in radiological exams. ICP sensors were implanted, observing high-ICP and establishing the diagnosis of craniocerebral disproportion. A two-stage surgical plan based on a dynamic cranial expansion followed by a supratentorial endoscopic aqueductoplasty was performed. A physical and mathematical model explaining our approach was also provided. RESULTS: Chess-table cranial expansion technique was performed in both patients. Six/seven days after the first surgery, respectively, ventricular dilation was observed in CT. Endoscopic precoronal aqueductoplasty was then performed. No postoperative complications were described. IFV symptoms improved in both patients. Eighteen and 12 months after the two-stage surgical plan, the patients remain symptom-free and void of flow is still observed between the third and the fourth ventricles in MRI. CONCLUSION: The two-stage approach was a suitable option for the treatment of these complex patients affected by both craniocerebral disproportion and isolated fourth ventricle.

Technical Nuances in Neuroendoscopic Lavage for Germinal Matrix Hemorrhage in Preterm Infants: Twenty Tips and Pearls after More than One Hundred Procedures.

INTRODUCTION: Posthemorrhagic hydrocephalus in preterm infants is a serious entity related to high mortality and morbidity. Neuroendoscopic lavage (NEL) is a suitable alternative for the management of this pathology. However, as with every endoscopic technique, it requires some experience and several cases to master. METHODS: We present a descriptive study of some technical nuances, tips, and tricks that have been learned in the last 8 years with over a hundred NELs performed in preterm infants. These variations are classified into 3 categories according to their temporal relationship with the surgical procedure: preoperative stage, intraoperative stage, and postoperative stage. We include a brief description of each one and the reasons why they are included in our current clinical practice. RESULTS: Twenty tips and pearls were described in detail and are reported here. Preoperative, intraoperative, and postoperative variations were exposed and related to the most frequent complications of this procedure: infection, cerebrospinal fluid leak, and rebleeding. CONCLUSIONS: NEL is a useful technique for the management of germinal matrix hemorrhage in preterm infants. These technical nuances have improved the results of our technique and helped us to prevent complications related to the procedure.

Correction to: Combined microsurgical fluorescence for optimizing resection in refractory empyema and cerebritis.

The original version of this article unfortunately contained an error. The corresponding author did not notice that one of the co-authors "Javier Márquez Márquez Rivas" was incorrectly presented. The correct name is "Javier Márquez Rivas". Given in this article is the corrected author name.

Combined microsurgical fluorescence for optimizing resection in refractory empyema and cerebritis.

PURPOSE: Due to the generalization of new microsurgical equipment, intraoperative fluorescence techniques have extended in neurosurgical practice, mainly in neurovascular and neuro-oncology patients. The aim of identifying pathological tissue and also differentiating from the normal brain helps neurosurgeons to approach other kinds of intracranial entities such as infections. METHODS: It is described in the case of an 11-year-old patient who underwent a subdural empyema by performing a craniotomy and evacuation of the purulent collection. After a non-optimal evolution, a frontobasal meningoencephalitis was assessed with cerebral involvement and associated intracranial hypertension. Indocyanine green (ICG) was used in reintervention for demonstrating a great damage of cortical vascularization around the infected area as well as fluorescein (FL), which identified a large area of avascularized tissue. RESULTS: Both techniques allowed a selective excision of the affected brain parenchyma while preserving viable parenchymal areas. Radiological evolution and clinical outcome were good. CONCLUSIONS: The identification of vascular patterns in brain lesions and the recognition of viable or necrotized tissues are suitable for a selective resection of the parenchyma, minimizing morbidity. Clinical outcome is related to a safe and effective management of inflammatory and infectious processes.

How I do it. 3D endoscopic treatment of metopic craniosynostosis through a single incision.

BACKGROUND: Endoscopic approaches for craniosynostosis are a growing field in pediatric neurosurgery. In metopic synostosis, previous reports for complete fronto-orbital remodeling have proposed an intervention with multiple incisions (bregmatic, tarsal, and preauricular) to open frontonasal and frontoethmoidal synostotic sutures, and orbital roof. METHODS: We propose a technique to complete all these osteotomies with a unique incision anterior to the bregmatic fontanel under 3D endoscopic vision, and review possible complications, limits, and pitfalls. CONCLUSIONS: Under endoscopic assistance, a complete fronto-orbital remodeling could be completed with a unique incision without mayor drawbacks.

Ventriculobiliary Shunts, Another Option.

The basic management of hydrocephalus includes shunts to the peritoneum and atrium. However, there are particularly complex patients in whom it is necessary to look for atypical places for implanting the distal catheter. Since 2000, 1,325 shunts have been implanted in pediatric patients. Only 3 patients required a ventriculobiliary shunt. We report 3 cases: a 7-year-old boy with a surgically treated complex heart disease, a 16-month-old girl with hydrocephalus secondary to a brain tumor and multiple bacteremias secondary to an infection of the central venous reservoir, and a 4-year-old girl with nonreabsorptive hydrocephalus caused by intraventricular bleeding due to premature birth, necrotizing enterocolitis and shunt infections with abdominal pseudocysts, which caused multiple abdominal septations and, finally, a nonreabsorptive peritoneum. At present, cases 1 [45 months after ventriculobiliary shunt (VBS)] and 3 (27 months after VBS) are symptom free, while case 2 (14 months after VBS) died of infectious respiratory complications. The gold standard for the treatment of nonreabsorptive hydrocephalus is a ventriculoperitoneal shunt, the second option is a ventriculoatrial shunt, and the third option is uncertain. In our short experience, a ventriculo-gallbladder shunt is a good option when there is no abdominal hypertension.

Endoscopy-Assisted Craniosynostosis Surgery without Postoperative Helmet Molding Therapy.

OBJECTIVE: Endoscopy-assisted craniosynostosis surgery (EACS) yields excellent surgical outcomes by minimizing blood loss, operative time, and hospital stays. Postoperative helmet therapy (PHT), commonly employed for head shape correction, involves frequent adjustments, potential complications, and high costs. Given the rising cost of helmet therapy, reduced insurance coverage, and limited availability in low- and middle-income countries, understanding success rates without helmet use is crucial. The present study analyses the anthropometric results of the first EACS series without PHT. METHODS: A retrospective analysis of a single-center series involving 90 consecutive patients who underwent EACS without PHT from 2012 to 2022 was conducted, with a follow-up exceeding 3 years. The study exclusively included patients with nonsyndromic isolated sagittal synostosis, with 33 meeting the criteria. Craniometric measurements were obtained from preoperative, 1-year postoperative, and the latest computed tomography scans. For isolated sagittal synostosis cases, the cephalic index (CI) was calculated (CI >75 for excellent results, CI 70-75 for good results, and <70 for poor results). Collected data encompassed patient sex, age, and follow-up time. RESULTS: The mean age was 84.8 ± 45.3 days (2.79 ± 1.49 months) within a range of 3-172 days. The preoperative mean CI was 68 ± 42, increasing to 76 ± 6 1 year postoperatively (mean difference +8 ± 6.3; P = 0.0001). Seventy-one percent of patients achieved excellent results, 23% good (CI = 70-75), and 6% poor. Reintervention was unnecessary. CONCLUSIONS: EACS without PHT demonstrates favorable anthropometric results, cost reduction, and simplified postoperative management.

Long-Term Success of Endoscopic Third Ventriculostomy in the Pediatric Population with Aqueductal Stenosis.

OBJECTIVE: To evaluate the long-term success rate of endoscopic third ventriculostomy (ETV) in the treatment of hydrocephalus due to aqueductal stenosis in the pediatric population. METHODS: Between January 2007 and June 2023, a total of 82 children underwent ETV surgery for hydrocephalus and met the inclusion criteria for our study. The children's medical records were reviewed, and cases requiring additional surgery in the months and years following surgery for ventriculostomy failure were reviewed. RESULTS: The mean age was 5.35 years. Successful ETV was observed in 74 children with a successful ETV rate of 90%. The median follow-up was 6.75 years (2 months-15.5 years). Eight children (10%) underwent additional surgery. In 7 cases, additional surgery was performed within 3 months, while in the remaining case, a delayed failure was noted (more than 3 years later). At 6 months and 3 years, the cumulative proportion of children with revision-free survival was 91%, declining slightly to 89% at 5 years. CONCLUSIONS: ETV is highly effective in treating hydrocephalus in pediatric patients with aqueductal stenosis, with a 91% success rate at 6 months and 3 years. Although the success rate drops slightly to 89% at 5 years, it still demonstrates durability. Late failures are usually characterized by symptoms of increased intracranial pressure. While patients with a confirmed successful ETV at 6 months may be considered for reduced follow-up frequency, it is critical to educate them about the symptoms of intracranial hypertension and the importance of seeking medical attention promptly if such symptoms occur.

Spinal elastofibroma: a case report.

Elastofibroma is a benign fibroproliferative tumor of unknown origin and pathogenesis. It usually appears in the subscapular or infrascapular area. It is extremely rare in the spinal area, and it is most common in middle-aged women. In most cases, it is asymptomatic. Its diagnosis is based on nuclear MRI, where it presents a homogeneous lesion, similar to the skeletal muscle, hyperintense in T1-weighted sequences and hypointense in T2-weighted sequences. This finding is confirmed with anatomical pathology tests, where it appears as a nonencapsulated lesion made up of wide collagen bands from connective tissue mixed with fat and muscle tissue. The treatment of choice is surgical removal of the lesion. We present a clinical case of elastofibroma, a benign and rare pathology with few described cases in the literature, in a patient with a previous dorsal lesion.

Primary cerebral radiotherapy-induced rhabdomyosarcoma: treatment with intraoperative carmustine implants.

INTRODUCTION: Primary cerebral rhabdomyosarcomas (cRMS) are extremely rare, with only 41 cases reported in the literature. Survival of patients with localized cRMS is 70% after 5 years but not in the case of intracranial neoplasms, where survival rarely exceeds 10 months. CASE REPORT: A 10-year-old female patient with a history of acute lymphoblastic leukemia (ALL) and holocranial radiotherapy (RT) 6 years ago, referred after partial surgical resection of a left parietal lesion, diagnosed as an embryonal tumor with mixed neuronal-glial differentiation (WHO grade IV). A second operation was performed for complete resection and placement of intracavitary chemotherapy (carmustine). The pathology revealed a high-grade undifferentiated neoplasm positive for myogenin and desmin that was compatible with cRMS. In the immunohistochemistry study, the neoplasm was positive for vimentin, myogenin, and desmin, as is characteristic of cRMS, and negative for synaptophysin and enolase, ruling out primitive neuroectodermal embriogenic tumor (PNET). Given a diagnosis of cRMS, a combined thoracoabdominal PET-CT scan was performed without finding other primary lesions and a bone marrow study was also performed without observing abnormalities. Consequently, the diagnosis was established as primary cRMS. DISCUSSION: Among the long-term sequelae of radiotherapy, neurocognitive disorders, brain disorders such as leukomalacia, vascular diseases, or secondary tumors, ranging from benign lesions such as meningiomas to more aggressive lesions such as ependymomas, which are high-grade gliomas, are described. In the brain MRI, our patient showed a radiotherapy-induced periventricular leukomalacia and a malignant lesion: a cRMS. The use of carmustine in this disease may facilitate local control.