Black hole sign migration in short-term brain CT scans: A possible link with clot evolution and histology

The black hole sign (BHS) is a rare radiological sign seen in the hyperacute phase of bleeding. It manifests within a hemorrhage in early hours, with limited studies exploring clot formation and evolution over a short duration. Despite various hypothesized mechanisms, the precise lifetime and dynamics of black hole sign development remain unclear. We describe the rare finding of a black hole sign within a deep brain hemorrhage, initially observed in the lateral portion of the clot during the first CT scan. Remarkably, in a subsequent CT scan, just 1 hour later, the BHS migrated towards the inner edge. Notably, while the hemorrhage size remained largely unchanged within this short timeframe, hyperacute bleeding led to increased perihematomal edema and sulci flattening. Histopathological features of the "evolving clot" are initially characterized by heightened cellularity. This increased cell density renders the hematoma less resistant to compressive forces, such as heightened endocranial pressure, offering a plausible explanation for the crushing and displacement of the BHS. Our study sheds light on the unique radiological progression of BHS within a deep brain ICH, emphasizing its association with dynamic clot formation and the consequential impact on surrounding structures.

Assessing the impact of mixed reality-assisted informed consent: A study protocol

Background

Informed consent is a crucial aspect of modern medicine, but it can be challenging due to the complexity of the information involved. Mixed reality (MR) has emerged as a promising technology to improve communication. However, there is a lack of comprehensive research on the impact of MR on medical informed consent. The proposed research protocol provides a solid foundation for conducting future investigations and developing MR-based protocols that can enhance patients' understanding and engagement in the decision-making process.

Methods

This study will employ a randomized controlled trial design. Two arms will be defined: MR-assisted informed consent (MRaIC) as the experimental arm and conventional informed consent (CIC) as the control arm consent, with 52 patients in each group. The protocol includes the use of questionnaires to analyze the anxiety levels and the awareness of the procedure that the patient is going to perform to study the impact of MRaIC versus CIC before medical procedures.

Results

The study will evaluate the impact of MR on patients' information comprehension, engagement during the process of obtaining informed consent, emotional reactions, and consent decisions. Ethical concerns will be addressed.

Conclusion

This study protocol provides a comprehensive approach to investigate the impact of MR on medical informed consent. The findings may contribute to a better understanding of the effects of MR on information comprehension, engagement during the process of obtaining informed consent, psychological experience, consent decisions, and ethical considerations. The integration of MR technology has the potential to enhance surgical communication practices and improve the informed consent process.

The role of extended reality in eloquent area lesions: a systematic review

OBJECTIVE

The surgical approach to lesions near eloquent areas continues to represent a challenge for neurosurgeons, despite all of the sophisticated tools currently used. The goal of surgery in eloquent areas is to maintain a good oncofunctional balance, that is, to preserve neurological function and ensure maximum tumor resection. Among all the available tools, extended reality (used to describe both virtual reality [VR] and mixed reality) is rapidly gaining a pivotal role in such delicate lesions, especially in preoperative planning, and recently, even during the surgical procedure. VR creates a completely new world in which only digital components are present. Augmented reality (AR), using software and hardware to introduce digital elements into the real-world environment, enhances the human experience. In addition, mixed reality, a more recent technique, combines VR and AR by projecting virtual objects into the real world, allowing the user to interact with them.

METHODS

A systematic literature review of the last 23.5 years was conducted (January 2000-June 2023) to investigate and discuss all progress related to the emerging role and use of these new technologies (VR, AR, and mixed reality), particularly in eloquent area lesions as a pre- and/or intraoperative tool.

RESULTS

Five hundred eighty-four published studies were identified. After removing duplicates and excluding articles that did not meet the inclusion criteria, 21 papers were included in the systematic review. The use of AR or VR was fully analyzed, considering their roles both intraoperatively and for surgical planning.

CONCLUSIONS

The increasing use of such innovative technologies has completely changed the way to approach a lesion, using 3D visualization to foster a better understanding of its anatomical and vascular characteristics.

Improving mixed-reality neuronavigation with blue-green light: a comparative multimodal laboratory study

OBJECTIVE

This study aimed to rigorously assess the accuracy of mixed-reality neuronavigation (MRN) in comparison with magnetic neuronavigation (MN) through a comprehensive phantom-based experiment. It introduces a novel dimension by examining the influence of blue-green light (BGL) on MRN accuracy, a previously unexplored avenue in this domain.

METHODS

Twenty-nine phantoms, each meticulously marked with 5-6 fiducials, underwent CT scans as part of the navigation protocol. A 3D model was then superimposed onto a 3D-printed plaster skull using a semiautomatic registration process. The study meticulously evaluated the accuracy of both navigation techniques by pinpointing specific markers on the plaster surface. Precise measurements were then taken using digital calipers, with navigation conducted under three distinct lighting conditions: indirect white light (referred to as no light [NL]), direct white light (WL), and BGL. The research enlisted two operators with distinct levels of experience, one senior and one junior, to ensure a comprehensive analysis. The study was structured into two distinct experiments (experiment 1 [MN] and experiment 2 [MRN]) conducted by the two operators. Data analysis focused on calculating average and median values within subgroups, considering variables such as the type of lighting, precision, and recording time.

RESULTS

In experiment 1, no statistically significant differences emerged between the two operators. However, in experiment 2, notable disparities became apparent, with the senior operator recording longer times but achieving higher precision. Most significantly, BGL consistently demonstrated a capacity to enhance accuracy in MRN across both experiments.

CONCLUSIONS

This study demonstrated the substantial positive influence of BGL on MRN accuracy, providing profound implications for the design and implementation of mixed-reality systems. It also emphasized that integrating BGL into mixed-reality environments could profoundly improve user experience and performance. Further research is essential to validate these findings in real-world settings and explore the broader potential of BGL in a variety of mixed-reality applications.

Unexpected Transient Glioblastoma Regression in a Patient Previously Treated with Bacillus Calmette-Guérin Therapy: A Case Report and Immunomodulatory Effects Hypothesis

(1) Background: Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with limited treatment options and poor prognosis. Bacillus Calmette-Guérin (BCG), a live attenuated strain of Mycobacterium bovis, has been used as an immunotherapeutic agent in bladder cancer and has shown non-specific beneficial effects. This report presents a unique case of GBM regression following BCG therapy for bladder cancer, suggesting the potential systemic immunomodulatory effects of BCG on GBM. (2) Case Presentation: A 67-year-old male with a history of bladder cancer treated with BCG presented with neurological symptoms. Imaging revealed two GBM lesions, and surgery was performed to remove one. Subsequently, the patient experienced complete tumor regression after initial stability. (3) Conclusions: This case highlights the potential of BCG or other immunotherapies in GBM treatment and underscores the need for further research. Understanding the immunomodulatory effects of BCG on GBM could lead to innovative therapies for this devastating disease; although, overcoming the immune evasion mechanisms in the brain is a significant challenge. Further investigation is warranted to explore this promising avenue of research.

Utility of sodium fluorescein in recurrent cervical vagus schwannoma surgery

Background

Cervical schwannoma is a rare neoplasm that usually occurs like a nondolent lateral neck mass but when growing and symptomatic requires radical excision. Sodium fluorescein (SF) is a dye that is uptake by schwannomas, which makes it amenable for its use in the resection of difficult or recurrent cases.

Methods

We describe the case of a patient presenting with a recurrence of a vagus nerve schwannoma in the cervical region and the step-by-step technique for its complete microsurgical exeresis helped by the use of SF dye.

Results

We achieved a complete microsurgical exeresis, despite the presence of exuberant perilesional fibrosis, by exploiting the ability of SF to stain the schwannoma and nearby tissues. That happens due to altered vascular permeability, allowing us to better differentiate the lesion boundaries and reactive scar tissue under microscope visualization (YELLOW 560 nm filter).

Conclusion

Recurrent cervical schwannoma might represent a surgical challenge due to its relation to the nerve, main cervical vessels, and the scar tissue encompassing the lesion. Although SF can cross both blood-brain and blood-tumor barriers, the impregnation of neoplastic tissue is still greater than that of nonneoplastic peripheric tissues. Such behavior may facilitate a safer removal of this kind of lesion while respecting contiguous anatomical structures.

Chronic encapsulated intracerebral hematomas: a systematic review

BACKGROUND

Chronic encapsulated intracerebral hematoma (CEICH) is a rare type of intracerebral hematoma (ICH) with peculiar radiological features and presenting as subtle slow-growing lesion exerting mass effect. We performed a systematic review of the literature focused on diagnosis and management of patients affected by CEICH.

MATERIAL AND METHODS

A literature search according to the PRISMA statement was conducted using PubMed and Scopus databases and pertinent Mesh terms. All papers that reported intraventricular CEICH, or CEICH cases treated conservatively or by CT-guided needle aspiration were not included in this study. A total of 40 papers were included in this review, with 58 patients (38 males and 20 females) and a mean age of 41.44 ± 20.05 years (range 1-80).

RESULTS

Neurological symptoms of onset include those related to an increase in intracranial pressure (ICP) in 28/58 cases (48.2%), seizures in 17/58 cases (29.3%), motor deficits in 14/58 cases (24.1%). The most frequent localization is atypical in 45/58 cases (77.6%). Surgical approach is not specified in 21/58 cases (36.2%), craniotomy was performed in 31/58 cases (53.4%), craniectomy in 5/58 cases (8.6%) and only in one case (1.7%) an endoscopic approach was performed. CEICH are usually located in an atypical site.

CONCLUSIONS

There is not an association with anticoagulants and antiplatelets intake. Arteriovenous malformation is the most frequent cause. Surgery is suggested, and craniotomy is the most used approach even if further investigation should be directed to analyze the efficacy of endoscopic approach of these lesions, which may show favorable outcome.

Coexistent meningioma in a patient with primary familial brain calcification: A case report

Primary familial brain calcification (PFBC) is an idiopathic pathology characterized by the development of calcific deposits in the supratentorial region such as telencephalon and diencephalon but also, in more extensive forms, in the cerebellum. Meningiomas are among the most common central nervous system (CNS) tumors generally related to a good prognosis. The simultaneous presence of intracerebral or extra-axial tumors and PFBC represents an exceedingly rare occurrence. A 72-year-old female patient was admitted to our department because of anoculogyric crisis followed by generalized seizures. She performed a brain CT scan which showed widespread hyperdensities in the paraventricular supratentorial region, basal ganglia and at the level of bilateral cerebellar dentate nuclei, characteristics of PFBC. Concomitant left frontal and smaller right temporal extra-axial lesions were identified and then confirmed in a brain MRI. The patient underwent a microsurgical resection of the lesion and subsequent histological examination reported a meningothelial meningioma (WHO Grade I). According to our literature review, this is the first paper that reports the coexistence of both intracranial meningiomas and PFBC. To date, it is not possible to provide an exact correlation between pathogenesis and genetic mechanism underlying this association.

Maximal Safe Resection in Glioblastoma Surgery: A Systematic Review of Advanced Intraoperative Image-Guided Techniques

Glioblastoma multiforme (GBM) represents the most common and aggressive central nervous system tumor associated with a poor prognosis. The aim of this study was to depict the role of intraoperative imaging techniques in GBM surgery and how they can ensure the maximal extent of resection (EOR) while preserving the functional outcome. The authors conducted a systematic review following PRISMA guidelines on the PubMed/Medline and Scopus databases. A total of 1747 articles were identified for screening. Studies focusing on GBM-affected patients, and evaluations of EOR and functional outcomes with the aid of advanced image-guided techniques were included. The resulting studies were assessed for methodological quality using the Risk of Bias in Systematic Review tool. Open Science Framework registration DOI 10.17605/OSF.IO/3FDP9. Eighteen studies were eligible for this systematic review. Among the selected studies, eight analyzed Sodium Fluorescein, three analyzed 5-aminolevulinic acid, two evaluated IoMRI imaging, two evaluated IoUS, and three evaluated multiple intraoperative imaging techniques. A total of 1312 patients were assessed. Gross Total Resection was achieved in the 78.6% of the cases. Follow-up time ranged from 1 to 52 months. All studies assessed the functional outcome based on the Karnofsky Performance Status scale, while one used the Neurologic Assessment in Neuro-Oncology score. In 77.7% of the cases, the functional outcome improved or was stable over the pre-operative assessment. Combining multiple intraoperative imaging techniques could provide better results in GBM surgery than a single technique. However, despite good surgical outcomes, patients often present a neurocognitive decline leading to a marked deterioration of the quality of life. Advanced intraoperative image-guided techniques can allow a better understanding of the anatomo-functional relationships between the tumor and the surrounding brain, thus maximizing the EOR while preserving functional outcomes.

Bilateral post-traumatic hygromas in patient with frontotemporal dementia

Background

Frontotemporal dementia (FTD) is a highly disabling neurologic disorder characterized by behavioral alterations and movement disorders, involving patients with a mean age of 58 years. We present a unique case of a patient suffering from FTD who developed post traumatic bilateral hygromas.

Case Description

A 52-year-old male patient, with an history of head trauma 3 months before, was admitted to our department for recurrent motor seizures. Anamnesis was positive for FTD with severe frontal syndrome. Brain computed tomography and magnetic resonance imaging (MRI) showed the typical "knife-blade" appearance of the cortical atrophy associated to bilateral hemispheric hygromas exerting mild mass effect. Brain MRI showed the signs of the cortical and "anti-cortical" vein. The two subdural collections were evacuated through two bilateral burr holes and controlled drainage. Despite anti-epileptic drugs therapy, in the early postoperative period, the patient presented further tonic-clonic seizures. The patient showed progressive recovery and was transferred to the neurorehabilitation center. After 6-month follow-up, he completely recovered.

Conclusion

In FTD, severe cortical atrophy leads to space increase between arachnoid and pia mater that could affect the anatomical integrity especially after trauma, with possible development of hygromas. The coexistence of radiological findings of the cortical vein and sign of the "anti-cortical" vein can make difficult an exact differential diagnosis between a primitive hygroma and a Virchow hygroma from resorption of previous blood collection. Surgical treatment may be indicated in selected patients, but it is burdened by higher postoperative risks compared to the general population.

Safeness and efficacy of 2-µm handheld thulium laser during microsurgical resection of supratentorial and infratentorial meningiomas: Experience of a single center

Aims

We performed a retrospective nonrandomized study to analyze the results of a microsurgery of intracranial meningiomas using 2-μm thulium flexible handheld laser fiber (Revolix jr).

Methods

From February 2014 to December 2021, 75 nonconsecutive patients suffering from intracranial meningiomas, admitted in our department, have been operated on with microsurgical technique assisted by 2-μm thulium flexible handheld laser. We have reviewed demographic and clinical data to evaluate safety and efficacy of the technique.

Results

There were no complications related to the use of the 2-μm thulium laser. We operated on a high percentage of cranial base and tentorial and posterior fossa meningioma in our series. The neurological outcome and degree of resection did not differ from previous series. The neurosurgical team found the laser easy to use and practical for avoiding bleeding and traction.

Conclusion

The use of 2-μm thulium fiber handheld flexible laser in microsurgery of intracranial meningiomas seems to be safe and to facilitate tumor resection, especially in "difficult" conditions (e.g., deep seated, highly vascularized, and hard tumors). Even if in this limited retrospective trial the good functional outcome following conventional microsurgery had not further improved, nor the surgical time was reduced by laser, focusing its use on "difficult" (large and vascularized) cases may lead to different results in the future.

Burr hole on polyetheretherketone cranioplasty for the management of chronic subdural hematoma: A case report

Background:

In rare cases, chronic subdural hematoma can be a complication following cranioplasty implantation. Therefore, it can develop spontaneously or after a trauma in the underlying site of a duroplasty and represent, if compression of the brain structures, a life-threatening condition. In case of a patient with cranioplasty in polyetheretherketone (PEEK), performing a burr hole on prosthesis can represent, although unusual, an effective and safe technique for evacuation of the chronic subdural hematoma, avoiding the need to remove the prosthesis itself. Nevertheless, a rare and insidious prosthesis infection can occur, even after years.

Case Description:

A 54-year-old male patient, following severe traumatic brain injury, underwent a right hemispheric decompressive craniectomy associated to acute subdural hematoma evacuation and, subsequently, a PEEK cranioplasty implant with polytetrafluoroethylene (PTFE or Gore-Tex) duroplasty. About 10 years later, he experienced worsening headache with sensory alterations; therefore, he underwent a brain computed tomography scan documenting a right hemispheric chronic subdural hematoma (cSDH), expanding in subsequent radiological examinations. Because of symptoms’ worsening, he underwent cSDH evacuation through a burr hole centered on the parietal region of the PEEK prosthesis, associated with mini-reopening of duroplasty. Two years after the procedure, he went to the emergency department because of the appearance of a serum-purulent material drained from the surgical site. He underwent cranioplasty removal and then started a targeted therapy to treat a triple surgical site infection, often unpredictable and totally accidental.

Conclusion:

Based on the literature evidence, performing a burr hole on a cranial prosthesis in bone-like material such as PEEK represents a surgical procedure never performed before and in our opinion could, in selected cases, guarantee the cSDH evacuation and the treatment of intracranial hypertension, avoiding the cranioplasty removal, although there is a risk of even late surgical site infection.

Spinal epidural abscess due to acute pyelonephritis

Background:

Spinal epidural abscesses are rare and are misdiagnosed in up to 75% of cases. Fever, back pain, and neurological deficits are part of the classical triad. Here, the authors report a patient with a L2–L5 spinal epidural abscess with the left paravertebral extension attributed to acute pyelonephritis.

Case Description:

A 54-year-old female presented with persistent low back pain and lower extremity weakness accompanied by paresthesias. Previously, she had been hospitalized with the left acute pyelonephritis. The lumbosacral MRI documented a T12/L5 anterior epidural abscess with ring enhancement on the contrast study; the maximum diameter of the abscess at the L2–L3 level contributed to severe cauda equina compression. She underwent a L2/L4 decompressive laminectomy with drainage of the intraspinal/extradural and paravertebral components. Intraoperative microbiological sampling grew Staphylococcus aureus for which she then received targeted antibiotic therapy. Fifteen days later, she was walking adequately when discharged.

Conclusion:

Thoracolumbar epidural abscesses are rare. They must be considered among the differential diagnoses when patients present with acute back pain, fever, and new neurological deficits following prior treatment for acute pyelonephritis.

Thoracic spinal extradural arachnoid cyst: A case report and literature review

Background:

Spinal extradural arachnoid cysts (SEDACs) are rare and are variously attributed to congenital, traumatic, or inflammatory etiologies. Here, we report a 70-year-old male who presented with a T11-T12 SEDAC and an incidental craniovertebral junction (CVJ) meningioma.

Case Description:

A 70-year-old male presented with progressive bilateral lower limb weakness and paresthesias. The thoracic MRI identified an extradural arachnoid cystic lesion at the T11-T12 level. In addition, the brain/ cervical MR documented an incidental meningioma at the CVJ. The patient underwent T11-T12 laminectomy for fenestration/removal of the extradural arachnoid cyst resulting in immediate cord decompression and neurological recovery. The histologic examination was consistent with a SEDAC who underwent successful resection of the SEDAC that resulted in symptom resolution.

Conclusion:

We presented a 71-year-old male with a thoracic SEDAC and an incidental CVJ meningioma, where resection of the SEDAC resulted in symptom resolution.

Neuroendoscopic Navigated One-Step Removal of Crossed Ventricular Catheter Fragments: Technical Note

Introduction Neuroendoscopy plays an important role in minimally invasive neurosurgery. The authors reported an interesting case of a pediatric patient with multiple ventriculoperitoneal shunt (VPS) revision surgeries, presenting with VPS infection and with two crossed intraventricular floating catheter fragments, successfully removed through a neuroendoscopic navigated one-step procedure. A literature review regarding this exceedingly rare condition has also been discussed.

Case Description An 11-year-old female patient with a history of congenital hydrocephalus was admitted to the emergency department with symptoms of intracranial hypertension, psychomotor agitation, and tetraparesis. She had a history of previous multiple VPS revisions. She had an urgent brain computed tomography scan that documented hydrocephalus; the VPS's intraventricular catheter tip was sited at the level of the right frontal horn. Two small floating catheter fragments, not connected to the VPS, were identified: the first close to the right lateral ventricle at the level of the right occipital horn, the second one between the right occipital horn and the third ventricle. First, she underwent an exteriorization of the distal catheter for VPS. Cerebrospinal fluid examination documented hyperproteinorrachia and a positive culture for Staphylococcus aureus. Then a navigated right transfrontal endoscopic approach to the right lateral ventricle was performed extending to the previous burr hole and achieving a wide range of working angle with a rigid 0-degree lens endoscope. Intermittent irrigation generating convective flow was performed such as to mobilize the catheters tip gently upward, to remove them by grasping. Finally, a whole VPS replacement has been performed.

Conclusion Persistence of intraventricular floating catheter fragments can lead to subacute or chronic infections. Neuroendoscopic retrieval represents a safe and effective alternative to a more extensive and invasive surgical approach. However, the exact catheter tip identification, grasping, and removal can be difficult to achieve, due to the technical instrumentation characteristics and altered intraventricular anatomy in chronic congenital hydrocephalus. In our experience, endoscopic convective flow induction through saline irrigation can determine floating intraventricular catheter fragments movement aiming to their identification and subsequent successful endoscopic retrieval.

Thoracic dumbbell spinal chordoma mimicking a schwannoma

Background:

Epidural dumbbell-shaped chordomas are localized slow growing, and malignant/aggressive neoplasms. Here, we present a 62-year-old male with a T3-T4 dumbbell-shaped chordoma and reviewed the appropriate literature.

Case Description:

A 62-year-old male presented with a three-month history of thoracic pain. When the thoracolumbar magnetic resonance (MR) showed a T3-T4 dumbbell-shaped intracanalicular/extradural tumor, he underwent tumor removal. After the histological examination proved the lesion was a spinal chordoma, he underwent a secondary radical transthoracic tumor resection. Postoperatively, the patient was able to walk without assistance, and at 6-month follow-up, was neurologically intact with only residual paresthesias.

Conclusion:

Malignant spinal chordomas may mimic benign neurinomas on MR scans. Here, biopsy of the lesion to confirm the diagnosis of chordoma was critical and directed subsequent definitive transthoracic tumor resection.

Delayed brain reexpansion in schizophrenic patient affected by trabecular type chronic subdural hematoma

Background:

Chronic subdural hematoma (cSDH) represents a complex and unpredictable disease, characterized by high morbidity and mortality, especially in elderly patients. Factors affecting the postoperative brain reexpansion along to cSDH recurrence have not been yet adequately investigated. The authors presented the case of a schizophrenic patient affected by trabecular type cSDH that presented a delayed brain reexpansion despite a craniotomy and membranotomy.

Case Description:

A 51-year-old female patient with diagnosis of schizophrenia was admitted to the emergency department with GCS score of 5/15 and right anisocoria. An urgent brain CT revealed a trabecular right cSDH (35 mm in maximum diameter) with recent bleeding. After surgery, a brain CT scan showed a markedly reduced brain reexpansion and pneumocephalus. Nevertheless, postoperative 7-day brain CT documented a progressive brain reexpansion with reduced midline shift.

Conclusion:

According to our opinion, anatomopathological alterations in schizophrenia reduce normal brain compliance and increasing elastance, thus modifying the normal timing of reexpansion after cSDH drainage, also after craniotomy and membranotomy. Although postoperative pneumocephalus is a well-known cause of hindered reexpansion, this could be due to anatomical alterations in schizophrenia. Such factors must be considered in the preoperative planning but mostly in the postoperative management.

Primary spinal Burkitt's lymphoma: Case report and literature review

Background:

Burkitt’s lymphoma is a non-Hodgkin B-cell lymphoma, occurring mostly in Equatorial Africa. According to the WHO, classification is three different variants: sporadic, endemic, and immunodeficient-associated. Here, we present a patient with “sporadic” primary epidural Burkitt’s lymphoma resulting in chronic low back pain (LBP).

Case Description:

A 63-year-old female presented with a 2-month history of LBP and the left lower extremity sciatica. The thoracolumbar MRI showed a L5 irregular, osteolytic epidural lesion that was hypointense on T1-weighted images, hyperintense on STIR studies, and inhomogeneously enhanced with contrast. Additional hypointense lesions were also seen at the L2, L3, and L4 levels. The patient underwent a L4-L5 laminectomy for piecemeal epidural resection of tumor, and a L4-S1 transpedicular screws/rod fusion. In addition, a L2-L3 radiofrequency ablation was performed. The histological examination documented a primary “sporadic” spinal Burkitt’s lymphoma. The patient subsequently was treated with both radiotherapy/chemoradiotherapy

Conclusion:

Primary “sporadic” spinal Burkitt’s lymphoma is rare. Following tumor resection, adjunctive radiation and chemotherapy are typically warranted.

Dural splitting reconstruction in retethering after lipomeningocele repair: Technical note

Background:

Tethered spinal cord syndrome (TCS) can occur after the surgical repair of lipomeningoceles (LMCs). In these cases, the tethering results from postoperative adhesions between the spinal cord and the overlying repaired dura. A watertight dural closure using the residual dura and/or the surrounding tissues does not always provide enough space for the spinal cord and risks retethering. Here, we report a 16-year-old patient with secondary TCS following lipomeningocele repair who successfully underwent release of the tethered filum terminale utilizing a novel dural splitting reconstructive technique to attain a water-tight closure without the need for a duroplasty.

Methods:

A 16-year-old patient had a LMC repaired at birth. She now presented with progressive low back pain, and gait disturbances. The MRI documented secondary spinal cord tethering at the prior spinal dysraphism repair site.

Results:

A secondary release of the filum terminale utilizing a novel dural splitting technique to avoid the need for a duroplasty was performed.

Conclusion:

Here, in a 16-year-old patient with a recurrent tethered cord syndrome following repair of a LMC at birth, we utilized a novel dural splitting reconstruction technique and averted the need for a duroplasty.

Spontaneous anterior cervicothoracic spinal epidural hematoma extending to clivus in SARS-CoV-2 infection

Background:

The treatment of spontaneous spinal epidural hematomas (SSEHs), depending on the lesion size and myeloradicular involvement, can be surgical or conservative. Here, we present a 55-year-old patient who sustained a SSEH several months following a systemic SARS-CoV-2 infection.

Case Description:

A 55-year-old immunocompromised female (i.e., history 17 years ago of Hodgkin’s lymphoma, nodular sclerosis variant) recently developed a SARS-CoV-2 infection treated with nonsteroidal anti-inflammatory agents. She then reported the sudden onset of cervicodorsalgia after a slight cervical flexion/extension maneuver. The brain and cervicothoracic spine MRI studies documented a clival anterior spinal epidural hematoma with maximum spinal compression at the T1-T2 level; it also extended inferiorly to the T6 level. Two weeks later, the follow-up MRI showed a remarkable reduction in the anteroposterior diameter of the hematoma that correlated with significant neurological improvement and almost complete pain regression. She was discharged after a total 15-day hospital stay, with complete symptoms relief.

Conclusion:

We present a 55-year-old chronically immunocompromised (i.e., due to the history of Hodgkin’s lymphoma) female who, following a SARS-CoV-2 infection, developed an anterior SSEH extending from the clivus to the T6 spinal level that spontaneously regressed without surgical intervention.

Focused Ultrasound in Neuroscience. State of the Art and Future Perspectives

Transcranial MR-guided Focused ultrasound (tcMRgFUS) is a surgical procedure that adopts focused ultrasounds beam towards a specific therapeutic target through the intact skull. The convergence of focused ultrasound beams onto the target produces tissue effects through released energy. Regarding neurosurgical applications, tcMRgFUS has been successfully adopted as a non-invasive procedure for ablative purposes such as thalamotomy, pallidotomy, and subthalamotomy for movement disorders. Several studies confirmed the effectiveness of tcMRgFUS in the treatment of several neurological conditions, ranging from motor disorders to psychiatric disorders. Moreover, using low-frequencies tcMRgFUS systems temporarily disrupts the blood-brain barrier, making this procedure suitable in neuro-oncology and neurodegenerative disease for controlled drug delivery. Nowadays, tcMRgFUS represents one of the most promising and fascinating technologies in neuroscience. Since it is an emerging technology, tcMRgFUS is still the subject of countless disparate studies, even if its effectiveness has been already proven in many experimental and therapeutic fields. Therefore, although many studies have been carried out, many others are still needed to increase the degree of knowledge of the innumerable potentials of tcMRgFUS and thus expand the future fields of application of this technology.

Publisher's Note: JLab Measurements of the ^{3}He Form Factors at Large Momentum Transfers [Phys. Rev. Lett. 119, 162501 (2017)]

This corrects the article DOI: 10.1103/PhysRevLett.119.162501.

JLab Measurements of the ^{3}He Form Factors at Large Momentum Transfers

The charge and magnetic form factors, F_{C} and F_{M}, respectively, of ^{3}He are extracted in the kinematic range 25  fm^{-2}≤Q^{2}≤61  fm^{-2} from elastic electron scattering by detecting ^{3}He recoil nuclei and scattered electrons in coincidence with the two High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements find evidence for the existence of a second diffraction minimum for the magnetic form factor at Q^{2}=49.3  fm^{-2} and for the charge form factor at Q^{2}=62.0  fm^{-2}. Both minima are predicted to exist in the Q^{2} range accessible by this Jefferson Lab experiment. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem.

Analysis of free-surface flows through energy considerations: Single-phase versus two-phase modeling

The study of energetic free-surface flows is challenging because of the large range of interface scales involved due to multiple fragmentations and reconnections of the air-water interface with the formation of drops and bubbles. Because of their complexity the investigation of such phenomena through numerical simulation largely increased during recent years. Actually, in the last decades different numerical models have been developed to study these flows, especially in the context of particle methods. In the latter a single-phase approximation is usually adopted to reduce the computational costs and the model complexity. While it is well known that the role of air largely affects the local flow evolution, it is still not clear whether this single-phase approximation is able to predict global flow features like the evolution of the global mechanical energy dissipation. The present work is dedicated to this topic through the study of a selected problem simulated with both single-phase and two-phase models. It is shown that, interestingly, even though flow evolutions are different, energy evolutions can be similar when including or not the presence of air. This is remarkable since, in the problem considered, with the two-phase model about half of the energy is lost in the air phase while in the one-phase model the energy is mainly dissipated by cavity collapses.

Energy-decomposition analysis for viscous free-surface flows

This work is dedicated to the energy decomposition analysis of a viscous free-surface flow. In the presence of a free surface, the viscous dissipation for a Newtonian liquid can be decomposed into two terms: an enstrophy component and a free-surface deformation component. The latter requires the evaluation of volume and surface integrals in the meshless framework. The analysis is based on the weakly compressible smoothed particle hydrodynamics formalism. The behavior of the energy terms is studied in standing wave problems by changing the viscosity and the wave amplitude. Finally, an analysis of a complex shallow water breaking wave case is provided. It is shown that in presence of intense breaking phenomena the two energy components are always comparable, whereas generally the free surface component is dominant on the viscous dissipation of gravity waves.

Precision Measurement of the p(e,e^{'}p)π^{0} Reaction at Threshold

New results are reported from a measurement of π^{0} electroproduction near threshold using the p(e,e^{'}p)π^{0} reaction. The experiment was designed to determine precisely the energy dependence of s- and p-wave electromagnetic multipoles as a stringent test of the predictions of chiral perturbation theory (ChPT). The data were taken with an electron beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. For the first time, complete coverage of the ϕ_{π}^{*} and θ_{π}^{*} angles in the pπ^{0} center of mass was obtained for invariant energies above threshold from 0.5 up to 15 MeV. The 4-momentum transfer Q^{2} coverage ranges from 0.05 to 0.155 (GeV/c)^{2} in fine steps. A simple phenomenological analysis of our data shows strong disagreement with p-wave predictions from ChPT for Q^{2}>0.07 (GeV/c)^{2}, while the s-wave predictions are in reasonable agreement.

Measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the reaction (3)He(↑)(e,e')X

We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3)He(↑)(e,e')X on a polarized (3)He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7<W<2.9  GeV, 1.0<Q(2)<4.0  GeV(2) and 0.16<x<0.65. Neutron asymmetries were extracted using the effective nucleon polarization and measured proton-to-(3)He cross-section ratios. The measured neutron asymmetries are negative with an average value of (-1.09±0.38)×10(-2) for invariant mass W>2  GeV, which is nonzero at the 2.89σ level. Our measured asymmetry agrees both in sign and magnitude with a two-photon-exchange model prediction that uses input from the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering.

JLab measurement of the 4He charge form factor at large momentum transfers

The charge form factor of 4He has been extracted in the range 29  fm(-2) ≤ Q2 ≤ 77  fm(-2) from elastic electron scattering, detecting 4He recoil nuclei and electrons in coincidence with the high resolution spectrometers of the Hall A Facility of Jefferson Lab. The measurements have uncovered a second diffraction minimum for the form factor, which was predicted in the Q2 range of this experiment. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the few-body problem.

Smoothed-particle-hydrodynamics modeling of dissipation mechanisms in gravity waves

The smoothed-particle-hydrodynamics (SPH) method has been used to study the evolution of free-surface Newtonian viscous flows specifically focusing on dissipation mechanisms in gravity waves. The numerical results have been compared with an analytical solution of the linearized Navier-Stokes equations for Reynolds numbers in the range 50-5000. We found that a correct choice of the number of neighboring particles is of fundamental importance in order to obtain convergence towards the analytical solution. This number has to increase with higher Reynolds numbers in order to prevent the onset of spurious vorticity inside the bulk of the fluid, leading to an unphysical overdamping of the wave amplitude. This generation of spurious vorticity strongly depends on the specific kernel function used in the SPH model.

Beam-target double-spin asymmetry A{LT} in charged pion production from deep inelastic scattering on a transversely polarized {3}He target at 1.4<Q{2}<2.7 GeV{2}

We report the first measurement of the double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused on the valence quark region, 0.16<x<0.35 with 1.4<Q{2}<2.7  GeV{2}. The corresponding neutron A{LT} asymmetries were extracted from the measured {3}He asymmetries and proton over {3}He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g{1T}{q} and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for π{-} production on {3}He and the neutron, while our π{+} asymmetries are consistent with zero.

Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized 3He Target at Q2 = 1.4-2.7 GeV2

We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.

High-resolution spectroscopy of Lambda16N by electroproduction

An experimental study of the (16)O(e,e'K(+))(Lambda)(16)N reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e,e'K(+))Lambda, Sigma(0) exclusive reactions and a precise calibration of the energy scale. A ground-state binding energy of 13.76+/-0.16 MeV was obtained for (Lambda)(16)N with better precision than previous measurements on the mirror hypernucleus (Lambda)(16)O. Precise energies have been determined for peaks arising from a Lambda in s and p orbits coupled to the p(1/2) and p(3/2) hole states of the (15)N core nucleus.

Investigation of proton-proton short-range correlations via the 12C(e,e'pp) reaction

We investigated simultaneously the 12C(e,e'p) and 12C(e,e'pp) reactions at Q2=2 (GeV/c)2, xB=1.2, and in an (e, e'p) missing-momentum range from 300 to 600 MeV/c. At these kinematics, with a missing momentum greater than the Fermi momentum of nucleons in a nucleus and far from the delta excitation, short-range nucleon-nucleon correlations are predicted to dominate the reaction. For (9.5+/-2)% of the 12C(e,e'p) events, a recoiling partner proton was observed back-to-back to the 12C(e,e'p) missing-momentum vector, an experimental signature of correlations.

High resolution spectroscopy of (lambda)(12)B by electroproduction

An experiment measuring electroproduction of hypernuclei has been performed in hall A at Jefferson Lab on a 12C target. In order to increase counting rates and provide unambiguous kaon identification two superconducting septum magnets and a ring imaging Cherenkov detector were added to the hall A standard equipment. An unprecedented energy resolution of less than 700 keV FWHM has been achieved. Thus, the observed (Lambda)(12)B spectrum shows for the first time identifiable strength in the core-excited region between the ground-state s-wave Lambda peak and the 11 MeV p-wave Lambda peak.

Neutron capture cross section measurement of 151Sm at the CERN neutron time of flight facility (n_TOF)

The151Sm(n,gamma)152Sm cross section has been measured at the spallation neutron facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The new facility combines excellent resolution in neutron time-of-flight, low repetition rates, and an unsurpassed instantaneous luminosity, resulting in rather favorable signal/background ratios. The 151Sm cross section is of importance for characterizing neutron capture nucleosynthesis in asymptotic giant branch stars. At a thermal energy of kT=30 keV the Maxwellian averaged cross section of this unstable isotope (t(1/2)=93 yr) was determined to be 3100+/-160 mb, significantly larger than theoretical predictions.

Possibility to deduce the emission time sequence of neutrons and protons from the neutron-proton correlation function

Experimental information has been derived from the neutron-proton correlation function in order to deduce the time sequence of neutrons and protons emitted at 45 degrees in the E/A = 45 MeV 58Ni + 27Al reaction.

The Use of Gaming Strategies in a Transcultural Setting

Saudi Arabia's vast economic resources have enabled the development of state-of-the-art hospitals. Nurses recruited from around the world staff these hospitals creating one of the most multicultural practice settings in the world. Ethnic, educational, and experiential diversity; language and communication barriers; and alternative ways of knowing and learning challenge nurse educators to be more creative and explore opportunities for greater participation and learning among various cultural groups. Gaming, as a teaching-learning strategy for multicultural participants, affords the necessary flexibility and nonthreatening atmosphere which facilitates positive interactions among different, and often competing, communication patterns and learning styles. This article explores how and why gaming is as an effective educational strategy in a transcultural setting.

The employer's bird's-eye view

Managed care has become a viable alternative for employers nationwide, Pittsburgh employers explain why.