Monitoring of Brain Tissue Oxygen Tension in Cardiac Arrest: a Translational Systematic Review from Experimental to Clinical Evidence.

BACKGROUND: Cardiac arrest (CA) is a sudden event that is often characterized by hypoxic-ischemic brain injury (HIBI), leading to significant mortality and long-term disability. Brain tissue oxygenation (PbtO2) is an invasive tool for monitoring brain oxygen tension, but it is not routinely used in patients with CA because of the invasiveness and the absence of high-quality data on its effect on outcome. We conducted a systematic review of experimental and clinical evidence to understand the role of PbtO2 in monitoring brain oxygenation in HIBI after CA and the effect of targeted PbtO2 therapy on outcomes. METHODS: The search was conducted using four search engines (PubMed, Scopus, Embase, and Cochrane), using the Boolean operator to combine mesh terms such as PbtO2, CA, and HIBI. RESULTS: Among 1,077 records, 22 studies were included (16 experimental studies and six clinical studies). In experimental studies, PbtO2 was mainly adopted to assess the impact of gas exchanges, drugs, or systemic maneuvers on brain oxygenation. In human studies, PbtO2 was rarely used to monitor the brain oxygen tension in patients with CA and HIBI. PbtO2 values had no clear association with patients' outcomes, but in the experimental studies, brain tissue hypoxia was associated with increased inflammation and neuronal damage. CONCLUSIONS: Further studies are needed to validate the effect and the threshold of PbtO2 associated with outcome in patients with CA, as well as to understand the physiological mechanisms influencing PbtO2 induced by gas exchanges, drug administration, and changes in body positioning after CA.

"COAGULATION": a mnemonic device for treating coagulation disorders following traumatic brain injury-a narrative-based method in the intensive care unit.

Introduction: Coagulopathy associated with isolated traumatic brain injury (C-iTBI) is a frequent complication associated with poor outcomes, primarily due to its role in the development or progression of haemorrhagic brain lesions. The independent risk factors for its onset are age, severity of traumatic brain injury (TBI), volume of fluids administered during resuscitation, and pre-injury use of antithrombotic drugs. Although the pathophysiology of C-iTBI has not been fully elucidated, two distinct stages have been identified: an initial hypocoagulable phase that begins within the first 24 h, dominated by platelet dysfunction and hyperfibrinolysis, followed by a hypercoagulable state that generally starts 72 h after the trauma. The aim of this study was to design an acronym as a mnemonic device to provide clinicians with an auxiliary tool in the treatment of this complication. Methods: A narrative analysis was performed in which intensive care physicians were asked to list the key factors related to C-iTBI. The initial sample was comprised of 33 respondents. Respondents who were not physicians, not currently working in or with experience in coagulopathy were excluded. Interviews were conducted for a month until the sample was saturated. Each participant was asked a single question: Can you identify a factor associated with coagulopathy in patients with TBI? Factors identified by respondents were then submitted to a quality check based on published studies and proven evidence. Because all the factors identified had strong support in the literature, none was eliminated. An acronym was then developed to create the mnemonic device. Results and conclusion: Eleven factors were identified: cerebral computed tomography, oral anticoagulant & antiplatelet use, arterial blood pressure (Hypotension), goal-directed haemostatic therapy, use fluids cautiously, low calcium levels, anaemia-transfusion, temperature, international normalised ratio (INR), oral antithrombotic reversal, normal acid-base status, forming the acronym "Coagulation." This acronym is a simple mnemonic device, easy to apply for anyone facing the challenge of treating patients of moderate or severe TBI on a daily basis.

Turning tables: a war-like approach to neurosurgical emergencies in the COVID-19 era.

During the Coronavirus-disease-2019 (COVID-19) pandemic emergency, neurosurgeons may have to decide to prioritize treatments to patients with the best chance of survival, as in a war setting triage. In this paper, we discussed factors that should be considered in the perioperative period and neurocritical care management of neurosurgical patients during a pandemic emergency; in particular, we focused on the decision on whether to operate or not a patient during the COVID-19 pandemic. A multidisciplinary expert panel composed by specialists with direct experience in COVID-19 management discussed and reviewed the criteria that should be taken into account in the decision to operate or not a patient during the COVID-19 pandemic. Disease-related factors should be first considered in order to precisely know the enemy we are facing. Patient-related factors should be then evaluated to understand the battleground on which we are facing the enemy. After these considerations, we must ascertain costs and expected outcomes of our surgical intervention by evaluation of surgery-related factors. Finally, the last factor that need to be evaluated before surgery is the availability of resources, staff, and ward availability for perioperative care. All these considerations will lead to the optimal organization and management of neurosurgical emergencies during pandemic times, considering the community and not only the single patient. We provided schematic preoperative considerations that we hope will help neurosurgeons to guide their decisions in these challenging times.

Anatomical meningo-orbital band evaluation and clinical implications: a cadaveric dissection study.

BACKGROUND: The meningo-orbital band (MOB) is a dural structure which runs around the superior orbital fissure (SOF) tethering the frontotemporal basal dura to the periorbita, through the SOF. MOB division is important to expose and remove the anterior clinoid process, to access to proximal carotid artery and cavernous sinus area. The aim of this study was to measure how the MOB could be safely incised without cranial nerves and cavernous sinus injuries. METHODS: Anatomical dissections and extradural exposure of the anterior clinoid process was performed on 20 cadavers (40 sides). Measurement of the MOB thickness was performed before its incision, after dura propria dissection, and retraction off the inner cavernous membrane, to expose the cranial nerves. RESULTS: We analyzed 20 cadaveric formalin-fixed heads injected with colored silicone, 11 man and 9 women of Caucasian race. The average length of a safe incision of the MOB was 10.6±1.1 mm on the right side, and 10.65±1.09 mm on the left side. CONCLUSIONS: In our study the average length of a safe incision of the MOB was 10.6±1.1 mm. Thus, the incision length of the MOB should not exceed 9 mm; the peeling of the anterior cavernous sinus and of the SOF, dissecting the two layers of the dura throughout the incision of the MOB, is a useful technique to avoid cranial nerves and cavernous sinus lesions.

Role of Anterior Nasal Packing in Endoscopic Skull Base Surgery: Italian Survey.

BACKGROUND: Nowadays, the endoscopic endonasal approach to sellar and parasellar region tumors is a common technique in neurosurgery, and surgical nuances, complications, and management strategies are shared in a multidisciplinary setting between neurosurgeons and ear, nose, and throat surgeons. Due to the heterogeneity of its variations, the role of the anterior nasal packing in endoscopic endonasal approach to the skull base surgery (EESBS) has not yet been unanimously accepted and no consensus or guidelines on its use exist. MATERIALS AND METHODS: A survey containing 10 questions about indications, management advantages, and pitfalls of the use of anterior nasal packing in EESBS was created by using an online open-source tool (SurveyMonkey). The questionnaire was sent to 39 Italian neurosurgical departments, which routinely adopt the endoscopic endonasal approach. RESULTS: Almost half of 39 selected centers (19; 48.7%) answered our survey. The main results can be summarized as 1) anterior nasal packing after EESBS is considered useful by 84% of participants, 2) prevention of epistaxis is the principal indication for anterior nasal packing, 3) the type of approach and skull base reconstruction influence the use of anterior nasal packing, and 4) nasal discomfort is considered the principal negative aspect of nasal packing. CONCLUSIONS: Our study identified that anterior nasal packing is commonly adopted in certain conditions, namely when extensive nasal dissection is performed. Furthermore, the choice to adopt or not the anterior nasal packing should be tailored taking in account specific conditions, such as acromegaly and Cushing disease. It represents an important factor in reducing postoperative sinonasal complications of EESB.

Management of spinal aneurysms associated with arteriovenous malformations: systematic literature review and illustrative case.

PURPOSE: Spinal aneurysms are rare vascular malformations, commonly associated with spinal AVMs. AVM-associated spinal aneurysms are burdened by significant morbidity. The purpose of our study is to evaluate the best treatment strategy for these uncommon vascular lesions and to report an illustrative case. METHODS: We reviewed clinical and radiological data of a patient surgically treated at our institution for a spinal AVM with an associated prenidal aneurysm. According to PRISMA guidelines, a systematic literature review has been performed in order to discuss the best management AVM-associated prenidal aneurysms. RESULTS: In the reported case, the aneurysm showed spontaneous regression at follow-up after surgical removal of the AVM. Only 6 articles reported management of spinal prenidal AVM-associated aneurysms. Basing on our experience and data from literature, surgical treatment of the aneurysm may be indicated along with the resection of the AVM if the aneurysm is close to the nidus. Conversely, if the aneurysm is far away from the nidus or in an unfavorable position, resection of the nidus only may lead to aneurysm regression as in the reported case. CONCLUSIONS: The treatment strategy for AVM-associated spinal aneurysms should be tailored on the single patient. In presence of large aneurysms that cause mass-effect symptoms, when rupture of the aneurysm is suspected or when treatment of the AVM is not proposable, direct treatment of the aneurysm should be considered. Otherwise, when complete resection of the nidus is performed, the eventually associated unruptured aneurysms located in challenging positions can be safely managed conservatively.

Middle Cranial Fossa Approach: Anatomical Study on Skull Base Triangles as a Landmark for a Safe Anterior Petrosectomy.

Objective The Kawase approach provides access to the petroclival and posterior cavernous sinus regions, cerebellopontine angle, and upper basilar artery territory. Nevertheless, it remains one of the most challenging approach for neurosurgeons, due to the considerable related morbidity and mortality. The goal of this study was to evaluate the relationship between anatomical landmarks and their possible variations, and to measure the extension of the Kawase space, to define the reliability of these landmarks while performing an anterior petrosectomy. Design Using eight cadaveric specimens (15 sides), an anatomical dissections and extradural exposure of the Kawase area were performed. Settings A two-step analysis of the distances between the mandibular branch of the trigeminal nerve (V3) and the structures at risk of iatrogenic damage was performed. Main outcome measures We measured the distance between V3 and the basal turn of the cochlea, and between V3 and the internal acoustic canal (IAC), analyzing the limits of bone resection without causing hearing damage. Results We analyzed eight cadaveric (15 sides) formalin-fixed heads injected with colored silicone: four males and four females of Caucasian race (mean age: 73.83 years). We found a mean distance of 10.46 ± 1.13 mm between the great superficial petrous nerve (GSPN) intersection with V3 and the basal turn of the cochlea, and of 11.92 ± 1.71 mm between the origin point of V3 from the Gasserian ganglion and the fundus of the IAC. Conclusion The knowledge of the safe distance between the most applicable anatomic landmarks and the hearing structures is a practical and useful method to perform this approach reducing related comorbidity.

How do you manage ANTICOagulant therapy in neurosurgery? The ANTICO survey of the Italian Society of Neurosurgery (SINCH).

BACKGROUND: Anticoagulant assumption is a concern in neurosurgical patient that implies a delicate balance between the risk of thromboembolism versus the risk of peri- and postoperative hemorrhage. METHODS: We performed a survey among 129 different neurosurgical departments in Italy to evaluate practice patterns regarding the management of neurosurgical patients taking anticoagulant drugs. Furthermore, we reviewed the available literature, with the aim of providing a comprehensive but practical summary of current recommendations. RESULTS: Our survey revealed that there is a lack of knowledge, mostly regarding the indication and the strategies of anticoagulant reversal in neurosurgical clinical practice. This may be due a lack of national and international guidelines for the care of anticoagulated neurosurgical patients, along with the fact that coagulation and hemostasis are not simple topics for a neurosurgeon. CONCLUSIONS: To overcome this issue, establishment of hospital-wide policy concerning management of anticoagulated patients and developed in an interdisciplinary manner are strongly recommended.

Ipsilateral Nasoseptal Flap Pedicle for Transpterygoid Approach: Technical Note.

INTRODUCTION: Transpterygoid approach is an expanded endonasal approach (EEA) that allows surgical access to the medial infratemporal fossa, to the skull base area of petrous bone and to the Meckel's cave. During this approach, a sacrifice of sphenopalatine artery is often required, leading to the need of contralateral Hadad-Bassagasteguy flap (HBF) or alternative reconstructive techniques. MATERIALS AND METHODS: We report a case of spontaneous CSF leak due to a meningo-encephalocele in the left lateral recess of sphenoid sinus, in which an ispilateral nasoseptal flap was harvest and sphenopalatine artery was preserved. RESULTS: We described the surgical technique adopted to preserve the ipsilateral nasoseptal vascular pedicle during transpterygoid approach and we performed a review of the pertinent literature. CONCLUSION: Wide exposure of the pterygoid base through transpterygoid approach could be obtained preserving the sphenopalatine artery, allowing skull base reconstruction with ipsilateral nasoseptal flap.

The role of external ventricular drainage for the management of posterior cranial fossa tumours: a systematic review.

Posterior cranial fossa tumours frequently develop hydrocephalus as first presentation in up to 80% of paediatric patients and 21.4% of adults, although it resolves after tumour removal in 70-90% and 96%, respectively. New onset hydrocephalus is reported in about 2.1% of adult and 10-40% of paediatric patients after posterior fossa surgery. There is no consensus concerning prophylactic external ventricular drainage (EVD) placement that is frequently used before posterior fossa lesion removal, as well in those cases without clear evidence of hydrocephalus. The aim of the study was to define the most correct management for patients who undergo posterior fossa tumour surgery, thus identifying cohorts of patients who are at risk of persistent hydrocephalus prior to surgery. A systematic review of literature has been performed, following PRISMA guidelines. Most of the studies reported CSF shunt only in the presence of hydrocephalus, whereas only a few authors suggested its prophylactic use in the absence of signs of ventricular dilatation. Predictive factors for postoperative hydrocephalus has been identified, including young age (< 3 years), severe symptomatic hydrocephalus at presentation, EVD placement before surgery, FOHR index > 0.46 and Evans index > 0.4, pseudomeningocele, CSF leak and infection. The use of pre-resection CSF shunt in case of signs and symptoms of hydrocephalus is mandatory, although it resolves in the majority of cases. As reported by several studies included in the present review, we suggest CSF shunt also in case of asymptomatic hydrocephalus, whereas it is not indicated without evidence of ventricular dilatation.

Escalation therapy in severe traumatic brain injury: how long is intracranial pressure monitoring necessary?

Traumatic brain injury frequently causes an elevation of intracranial pressure (ICP) that could lead to reduction of cerebral perfusion pressure and cause brain ischemia. Invasive ICP monitoring is recommended by international guidelines, in order to reduce the incidence of secondary brain injury; although rare, the complications related to ICP probes could be dependent on the duration of monitoring. The aim of this manuscript is to clarify the appropriate timing for removal and management of invasive ICP monitoring, in order to reduce the risk of related complications and guarantee adequate cerebral autoregulatory control. There is no universal consensus concerning the duration of invasive ICP monitoring and its related complications, although the pertinent literature seems to show that the longer is the monitoring maintenance, the higher is the risk of technical issues. Besides, upon 72 h of normal ICP values or less than 72 h if the first computed tomography scan is normal (none or minimal signs of injury) and the neurological exam is available (allowing to observe variations and possible occurrence of new-onset pathological response), the removal of invasive ICP monitoring can be justified. The availability of non-invasive monitoring systems should be considered to follow up patients' clinical course after invasive ICP probe removal or for substituting the invasive monitoring in case of contraindication to its placement. Recently, optic nerve sheath diameter and straight sinus systolic flow velocity evaluation through ultrasound methods showed a good correlation with ICP values, demonstrating their potential role in place of invasive monitoring or in the early weaning phase from the invasive ICP monitoring.

Escalate and De-Escalate Therapies for Intracranial Pressure Control in Traumatic Brain Injury.

Severe traumatic brain injury (TBI) is frequently associated with an elevation of intracranial pressure (ICP), followed by cerebral perfusion pressure (CPP) reduction. Invasive monitoring of ICP is recommended to guide a step-by-step "staircase approach" which aims to normalize ICP values and reduce the risks of secondary damage. However, if such monitoring is not available clinical examination and radiological criteria should be used. A major concern is how to taper the therapies employed for ICP control. The aim of this manuscript is to review the criteria for escalating and withdrawing therapies in TBI patients. Each step of the staircase approach carries a risk of adverse effects related to the duration of treatment. Tapering of barbiturates should start once ICP control has been achieved for at least 24 h, although a period of 2-12 days is often required. Administration of hyperosmolar fluids should be avoided if ICP is normal. Sedation should be reduced after at least 24 h of controlled ICP to allow neurological examination. Removal of invasive ICP monitoring is suggested after 72 h of normal ICP. For patients who have undergone surgical decompression, cranioplasty represents the final step, and an earlier cranioplasty (15-90 days after decompression) seems to reduce the rate of infection, seizures, and hydrocephalus.

Neurological Manifestations of Severe SARS-CoV-2 Infection: Potential Mechanisms and Implications of Individualized Mechanical Ventilation Settings.

In December 2019, an outbreak of illness caused by a novel coronavirus (2019-nCoV, subsequently renamed SARS-CoV-2) was reported in Wuhan, China. Coronavirus disease 2019 (COVID-19) quickly spread worldwide to become a pandemic. Typical manifestations of COVID-19 include fever, dry cough, fatigue, and respiratory distress. In addition, both the central and peripheral nervous system can be affected by SARS-CoV-2 infection. These neurological changes may be caused by viral neurotropism, by a hyperinflammatory and hypercoagulative state, or even by mechanical ventilation-associated impairment. Hypoxia, endothelial cell damage, and the different impacts of different ventilatory strategies may all lead to increased stress and strain, potentially exacerbating the inflammatory response and leading to a complex interaction between the lungs and the brain. To date, no studies have taken into consideration the possible secondary effect of mechanical ventilation on brain recovery and outcomes. The aim of our review is to provide an updated overview of the potential pathogenic mechanisms of neurological manifestations in COVID-19, discuss the physiological issues related to brain-lung interactions, and propose strategies for optimization of respiratory support in critically ill patients with SARS-CoV-2 pneumonia.

Tonsillar herniation spectrum: more than just Chiari I. Update and controversies on classification and management.

Cerebellar tonsil herniation comprises a spectrum of disorders sharing a common neuroimaging finding consisting of downward displacement of the cerebellar tonsils through the foramen magnum and into the upper cervical spinal canal. This not uncommon condition may result from a large host of congenital or acquired causes, and confusion regarding its classification and pathogenesis still exists. Terminology also remains heterogeneous, including inconsistencies in the usage of the "Chiari 1" monicker. In this paper, the hypothesized mechanisms of development of tonsillar herniation are reviewed and strategies of management are discussed, with particular attention to surgical options adapted to the underlying etiology. A focus will be placed on acquired causes of tonsillar herniation.