Relative Hypercoagulopathy of the SARS-CoV-2 Beta and Delta Variants when Compared to the Less Severe Omicron Variants Is Related to TEG Parameters, the Extent of Fibrin Amyloid Microclots, and the Severity of Clinical Illness.

Earlier variants of SARS-CoV-2 have been associated with hypercoagulability and an extensive formation of fibrin amyloid microclots, which are considered to contribute to the pathology of the coronavirus 2019 disease (COVID-19). The newer omicron variants appear to be far more transmissible, but less virulent, even when taking immunity acquired from previous infections or vaccination into account. We here show that while the clotting parameters associated with omicron variants are significantly raised over those of healthy, matched controls, they are raised to levels significantly lower than those seen with more severe variants such as beta and delta. We also observed that individuals infected with omicron variants manifested less extensive microclot formation in platelet-poor plasma compared with those harboring the more virulent variants. The measurement of clotting effects between the different variants acts as a kind of "internal control" that demonstrates the relationship between the extent of coagulopathies and the virulence of the variant of interest. This adds to the evidence that microclots may play an important role in reflecting the severity of symptoms observed in COVID-19.

Incidence of venous thromboembolism in hospitalized pediatric neurosurgical patients: a retrospective 25-year institutional experience.

PURPOSE: Venous thromboembolism (VTE) refers to both deep venous thrombosis (DVT) and pulmonary embolism (PE). The risk of VTE in adult neurosurgical patients is thoroughly studied. However, the incidence and risk of VTE in a comprehensive pediatric neurosurgical population is not well-defined. The available pediatric data consists of reviews of specific high-risk groups, such as trauma, critical care, or cancer patients. This may not be reflective of the entire spectrum of a high-volume pediatric neurosurgery practice. This study was undertaken to analyze the incidence and risk factors of VTE in all hospitalizations evaluated by a pediatric neurosurgery service over a 25-year period. METHODS: A retrospective review of electronic medical records was performed for 9149 hospitalizations in 6374 unique patients evaluated by the pediatric neurosurgery service at Riley Hospital for Children (Indianapolis, IN, USA) from 1990-2014. During this time period, there was no standardized VTE prevention protocol. The study group included all patients less than 18 years of age. Patients with a known pre-existing VTE or pregnancy were excluded. RESULTS: VTE was diagnosed in 20 of the 9149 (0.22%) hospitalizations, in 18 unique patients. All DVTs were diagnosed via Doppler ultrasound and/or computed tomography. Anatomic clot locations included 9 in the upper extremity (0.098% of hospitalizations), 8 in the lower extremity (0.087%), and 4 (0.044%) pulmonary emboli. Ten of the 20 occurred in hospitalizations where the patient underwent surgery, although the need for surgery was not a statistically significant risk factor. Sixteen of the 20 (80%) occurred in patients with at least one form of central venous line (p < 0.00001). There was one VTE-related death (0.01%). CONCLUSIONS: In all pediatric neurosurgical patients, a VTE was found in 0.22% of hospitalizations over a 25-year span. Statistically significant risk factors for VTE included central venous line placement, paralysis, malignancy, intubation greater than 48 h, and hypercoagulable state.

Filum Terminale Ependymoma in an Infant with Meningocele.

This report describes a case of an ependymoma found in the setting of tethered cord syndrome. We present a 3-month-old girl with prenatal diagnosis of lumbar meningocele who later underwent tethered cord release. After birth, she was neurologically intact and only found to have a skin-covered meningocele. An MRI was obtained and significant for low-lying conus terminating at L5, a focal syrinx, and Chiari II malformation. She underwent an elective meningocele repair and resection of thickened filum for tethered cord release at 3 months of age. Unexpectedly, microscopic evaluation of the filum was consistent with a small focus of ependymoma in addition to the filum tissue. Previous case reports have suggested a link between thickened filum in the setting of spinal dysraphism and myxopapillary ependymoma, but to our knowledge, this is the first report of ependymoma in the setting of tethered cord syndrome.

Thromboelastography-Guided Therapy of Hemorrhagic Complications after Craniopharyngioma Resection: Case-Based Update.

PURPOSE: Thromboelastography (TEG) is a point-of-care test that evaluates the entire hemostatic process. The use of TEG is expanding in multiple pediatric surgical disciplines. However, there is very little literature regarding its application in pediatric neurosurgical patients. METHODS: The authors provide a case-based update and literature review regarding potential applications of TEG to pediatric neurosurgical patients. RESULTS: The authors describe a 12-year-old female who experienced a number of complications after a craniopharyngioma resection. The patient suffered multiple new intraventricular hemorrhages with removal of external ventricular drains. Standard coagulopathy tests did not reveal any abnormalities. However, an abnormal TEG value suggested primary hyperfibrinolysis, which led to a change in medical management. The patient did not suffer any further bleeding episodes after the change in treatment. CONCLUSIONS: The authors discuss a case where TEG influenced patient management and identified a problem despite normal values of standard laboratory tests. Neurosurgeons should be aware of the potential benefits for TEG testing in pediatric patients.

Primary Spinal Intradural Extraosseous Ewing Sarcoma in a Pediatric Patient: Case Report and Review of the Literature.

Ewing sarcoma (ES) is an aggressive, primary bone malignancy with occasional soft tissue extension. Purely extra-osseous ES is rare. A primary intraspinal, intradural ES without bone involvement is exceedingly rare. ES may be differentiated from other primitive neuroectodermal tumors by molecular analysis. The authors report the case of a 14-year-old female who suffered an acute neurologic decline from a hemorrhagic, intraspinal, intradural ES. The patient has been tumor free for 2 years after the initial emergency surgery. Our management of the patient and a review of the literature are provided. Considering only those cases with molecular or genetic confirmation of ES, our patient is the fifth pediatric case reported in the English literature.

Frontal burr hole approach for neuroendoscopic resection of craniopharyngioma with the NICO Myriad device: report of two cases.

OBJECTIVE: Craniopharyngiomas are challenging tumors to resect due to their deep location and proximity to vital structures. The perceived benefit of gross total resection may be tempered by the possibility of permanent disability. Minimally invasive techniques may reduce surgical morbidity while still allowing effective resection. The authors describe their initial experience with a neuroendoscopic transcortical, transventricular approach to two craniopharyngiomas. The surgeries were performed through a right frontal burr hole using the NICO Myriad, a side-cutting, aspiration device that fits through the working channel of a standard neuroendoscope. METHODS: The imaging and medical records of two children (a 5-year-old male and a 9-year-old female) undergoing endoscopic resection of a craniopharyngioma with this technique were reviewed. Outcomes, results, and complications were noted. RESULTS: A gross total resection was achieved in both patients. The operative time was 180 and 143 min, respectively. The estimated blood loss was 20 and 50 cm3, respectively. Both patients required a cerebrospinal fluid shunt. There were no surgical complications. CONCLUSIONS: The NICO Myriad is an effective tool that allows a safe minimally invasive endoscopic resection of craniopharyngiomas in patients with amenable anatomy. Surgeons with experience in neuroendoscopy may be able to achieve a gross total resection of these challenging tumors through a minimally invasive burr hole approach.

Analysis of the potential risk of central intravenous lines and/or total parenteral nutrition with ventriculoatrial shunts.

OBJECT: The distal catheter of a ventriculoatrial (VA) cerebrospinal fluid shunt is potentially exposed to bacterial seeding from a subclavian central line. The risk of blood stream infections (BSIs) from central lines increases with administration of total parenteral nutrition (TPN). The potential risks of shunt malfunction or infection in patients with a VA shunt and a concurrent subclavian central line and/or TPN administration have not been studied. METHODS: A retrospective review of 49 pediatric patients with placement of a VA shunt was performed. Three outcome measures were studied: shunt malfunction, shunt infection, and bacteremia/fungemia requiring shunt removal. All outcomes were measured by 1 year after shunt insertion. We analyzed the following potential risk factors: age at shunt insertion, prior ventriculoperitoneal (VP) shunt, prior shunt infection, abdominal infection/necrotizing enterocolitis (NEC), concurrent subclavian central line, and administration of TPN. The association between each risk factor and outcome was evaluated using Fisher's exact test to generate the relative risk. Additionally, a logistic regression analysis was performed to evaluate the odds ratio of the outcomes to risk factors considering age as a covariate. RESULTS: The average age at shunt insertion was 6.3 ± 7.6 years. The most common diagnosis was posthemorrhagic hydrocephalus of prematurity (53.1 %). Fifteen patients (30.1 %) had a shunt malfunction within 1 year, 6 (12.2 %) had a shunt infection, and 3 (6.1 %) required removal of the shunt due to bacteremia/fungemia. The age at shunt insertion was not a statistically significant independent risk factor for any of the three outcomes. Prior shunt infection predicted an increased risk for both future shunt malfunction and infection in both the associative relative risk analysis and the age-dependent logistic regression analysis, although the correlation did not reach statistical significance. The presence of a subclavian central line or TPN administration did not statistically increase the risk over baseline for any of the outcomes in either analysis. CONCLUSIONS: The relatively small number of patients limits the power of the study. Considering this limitation, the data suggests that the presence of a concurrent subclavian central line or administration of TPN does not increase the risk of shunt malfunction or infection over the baseline of this high-risk cohort.

Cloacal exstrophy with extensive Chiari II malformation: case report and review of the literature.

INTRODUCTION: Cloacal exstrophy is a rare condition characterized by a defect in the abdominal wall with extrusion of malformed abdominal contents. The normal separation of the genitourinary and gastrointestinal systems does not occur. While patients with cloacal exstrophy have a high incidence of spinal defects, cranial defects are rare. Chiari malformation has been rarely reported in children with cloacal exstrophy, although the embryogenesis is unknown. OBJECTIVE: In this report, the authors describe a child with cloacal exstrophy and a large myelocystocele. The child also had an extensive Chiari II malformation. RESULTS: We review the relevant embryology and suggest a possible mechanism for Chiari formation in this patient.

Clinical outcomes of the surgical treatment of isolated unilateral facet fractures, subluxations, and dislocations in the pediatric cervical spine: report of eight cases and review of the literature.

PURPOSE: We present a small series consisting of eight children with unilateral facet injury of the cervical spine treated surgically. METHODS: A retrospective review was performed. Injury data, radiographs, surgical data, and outcomes (Neck Disability Index (NDI), Short Form 36 (SF-36), and Visual Analog Scale for Neck Pain (VAS-NP)) were collected from seven patients. A literature review was performed for one additional case. RESULTS: Motor vehicle accidents (62 %, n = 5) and falls (38 %, n = 3) accounted for all injuries. The C6-7 level accounted for most of the injuries (37.5 %, n = 3). The mean NDI score with at least 3 months follow-up was 5.3 (n = 6, range, 1-12; standard deviation, 4.5), corresponding to mild disability. Of the norm-based SF-36 scale scores available (n = 6), the mean physical functioning (PF), role-physical (RP), and role-emotional (RE) scores were significantly less than the adult, age 18-24, norm-based means, with a mean difference of -6.4, -9.13, and -11.3, respectively (p value = 0.03, 0.001, and 0.01, respectively). The mean general health (GH) and vitality (VT) scores, however, were significantly greater than the adult, age 18-24, norm-based mean, with a mean difference of 7.82 and 10.3 (p = 0.04 and 0.02, respectively). VAS-NP showed a return to the "no pain" level at 3 months or more follow-up in all patients. CONCLUSIONS: We suggest that surgical treatment of these injuries in the pediatric age group may lead to satisfactory clinical and radiographic outcomes, but HRQoL analysis suggests that patients remain physically and emotionally disabled to some degree after surgery.

Rh-BMP-2 for L5-S1 arthrodesis in long fusions to the pelvis for neuromuscular spinal deformity in the pediatric age group: analysis of 11 patients.

PURPOSE: Neuromuscular scoliosis is a challenging pathology to treat with high incidence of complications and failure of surgical fusion. Surgical correction can entail long fusion constructs extending to the pelvis. We report our experience in the use of bone morphogenetic protein (BMP) to augment L5-S1 arthrodesis in long segment fusions in pediatric patients with neuromuscular scoliosis. METHODS: Retrospective review of 11 pediatric patients with neuromuscular spinal deformity (mean, age 13.7 years; range, 10-20 years) who underwent long (mean, 15 levels; range, 10-18 levels) spinal instrumentation and fusion to the pelvis at a single institution from 2007 to 2012 with an average follow-up of 34 months (range, 11-62 months). RESULTS: Of the 11 patients, one had pseudoarthrosis at L5-S1. The average coronal Cobb angle measured 59° before surgery and 42° immediately after surgery. The average preoperative thoracic kyphosis and lumbar sagittal lordosis measured 34 and 59°, respectively. Immediately after surgery, the thoracic and lumbar angles measured 28 and 39°, respectively. At last follow-up, the average coronal Cobb angle was maintained at 43° and the thoracic and lumbar sagittal angles were 28 and 44°, respectively. An average of 14.2 mg of recombinant human bone morphogenetic protein-2 (rh-BMP-2) was used for each case. CONCLUSIONS: L5-S1 arthrodesis may be effectively achieved in long fusions for pediatric neuromuscular spinal deformity with posterolateral fusion supplemented with rh-BMP-2. This surgical strategy may be associated with lower complication rates, decreased blood loss, and shorter operative times than circumferential fusion, which is particularly important in this complex fragile patient population.

Brodifacoum contamination of synthetic cannabinoid causing unexplained coagulopathy in multiple trauma: A case report.

An 18-year-old female presented to the emergency department after a motor vehicle collision. Initial imaging revealed a liver laceration. Subsequent labs showed significantly elevated prothrombin time, international normalized ratio, and activated partial thromboplastin time. Thromboelastography demonstrated a flatline tracing. The patient denied use of anticoagulation but admitted to synthetic cannabinoid use. It was believed the patient had taken synthetic cannabinoid contaminated by brodifacoum. She was therefore given prothrombin complex concentrate and vitamin K with blood products. The patient underwent sequential embolization, laparotomy, thoracotomy, and repair of the vena cava with a shunt. Thirty minutes postoperatively, her coagulation tests and thromboelastography were much improved. Two and a half hours postoperatively, it was determined she had sustained non-survivable injuries. The patient experienced brain death due to prolonged hypotension as a result of hemorrhagic shock with bleeding exacerbated by brodifacoum. To our knowledge, this is the first case reported of a trauma-induced coagulopathy exacerbated by brodifacoum-contaminated synthetic cannabinoid. Her coagulopathy was clearly not due to trauma alone and contributed greatly to the difficulty in controlling hemorrhage. The synthetic cannabinoid-associated coagulopathy rendered her otherwise potentially survivable injuries fatal. Given the frequency of multiple trauma and the recent increase in the prevalence of synthetic cannabinoid, it can be expected that the incidence of trauma complicated by synthetic cannabinoid-associated coagulopathy will increase in the near future. For patients that present with prolonged prothrombin time and/or activated partial thromboplastin time, it is important to inquire about recent synthetic cannabinoid use.

Markers of Futile Resuscitation in Traumatic Hemorrhage: A Review of the Evidence and a Proposal for Futility Time-Outs during Massive Transfusion.

The reduction in the blood supply following the 2019 coronavirus pandemic has been exacerbated by the increased use of balanced resuscitation with blood components including whole blood in urban trauma centers. This reduction of the blood supply has diminished the ability of blood banks to maintain a constant supply to meet the demands associated with periodic surges of urban trauma resuscitation. This scarcity has highlighted the need for increased vigilance through blood product stewardship, particularly among severely bleeding trauma patients (SBTPs). This stewardship can be enhanced by the identification of reliable clinical and laboratory parameters which accurately indicate when massive transfusion is futile. Consequently, there has been a recent attempt to develop scoring systems in the prehospital and emergency department settings which include clinical, laboratory, and physiologic parameters and blood products per hour transfused as predictors of futile resuscitation. Defining futility in SBTPs, however, remains unclear, and there is only nascent literature which defines those criteria which reliably predict futility in SBTPs. The purpose of this review is to provide a focused examination of the literature in order to define reliable parameters of futility in SBTPs. The knowledge of these reliable parameters of futility may help define a foundation for drawing conclusions which will provide a clear roadmap for traumatologists when confronted with SBTPs who are candidates for the declaration of futility. Therefore, we systematically reviewed the literature regarding the definition of futile resuscitation for patients with trauma-induced hemorrhagic shock, and we propose a concise roadmap for clinicians to help them use well-defined clinical, laboratory, and viscoelastic parameters which can define futility.

Traumatic Brain Injury as an Independent Predictor of Futility in the Early Resuscitation of Patients in Hemorrhagic Shock.

This review explores the concept of futility timeouts and the use of traumatic brain injury (TBI) as an independent predictor of the futility of resuscitation efforts in severely bleeding trauma patients. The national blood supply shortage has been exacerbated by the lingering influence of the COVID-19 pandemic on the number of blood donors available, as well as by the adoption of balanced hemostatic resuscitation protocols (such as the increasing use of 1:1:1 packed red blood cells, plasma, and platelets) with and without early whole blood resuscitation. This has underscored the urgent need for reliable predictors of futile resuscitation (FR). As a result, clinical, radiologic, and laboratory bedside markers have emerged which can accurately predict FR in patients with severe trauma-induced hemorrhage, such as the Suspension of Transfusion and Other Procedures (STOP) criteria. However, the STOP criteria do not include markers for TBI severity or transfusion cut points despite these patients requiring large quantities of blood components in the STOP criteria validation cohort. Yet, guidelines for neuroprognosticating patients with TBI can require up to 72 h, which makes them less useful in the minutes and hours following initial presentation. We examine the impact of TBI on bleeding trauma patients, with a focus on those with coagulopathies associated with TBI. This review categorizes TBI into isolated TBI (iTBI), hemorrhagic isolated TBI (hiTBI), and polytraumatic TBI (ptTBI). Through an analysis of bedside parameters (such as the proposed STOP criteria), coagulation assays, markers for TBI severity, and transfusion cut points as markers of futilty, we suggest amendments to current guidelines and the development of more precise algorithms that incorporate prognostic indicators of severe TBI as an independent parameter for the early prediction of FR so as to optimize blood product allocation.

Corrigendum: Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies.

[This corrects the article DOI: 10.3389/fimmu.2023.1230049.].

Sequential imaging demonstrating os odontoideum formation after a fracture through the apical odontoid epiphysis: case report and review of the literature.

INTRODUCTION: The mechanism of formation of an os odontoideum is controversial and likely multifactorial. One theory states that the apex of the odontoid separates from the body because of a fracture. The intact alar and apical ligaments pull the fractured segment superiorly. The independent vascular supply of the apex allows the fractured bone to remain viable and remodel into the smooth, corticated bone characteristic of an os odontoideum. However, there are no publications with direct radiographic evidence supporting the theory. CASE REPORT: In this paper, the authors present a 7-year-old child with a fracture through the apical odontoid epiphysis, extending into the body of the dens. Serial imaging studies demonstrate progressive separation of the apex from the body of the odontoid. The fractured segment begins to remodel and assume the classic form of an os. CONCLUSION: The authors consider this case to be radiographic evidence supporting an acquired/traumatic origin of os odontoideum. Further, the mechanism of fracture through a cartilaginous epiphysis may explain the formation of an os after "normal" x-ray images or following seemingly minor trauma.

Neurophysiologic intraoperative monitoring in children with Down syndrome.

OBJECTIVE: Neurophysiological monitoring during complex spine procedures may reduce risk of injury by providing feedback to the operating surgeon. This tool is a well-established and important surgical adjunct in adults, but clinical data in children are not well described. Moreover, to the best of our knowledge, neurophysiologic intraoperative monitoring data have not been reported in children with neurodevelopmental disorders, such as Down syndrome, who commonly present with craniocervical instability requiring internal fixation. The purpose of this study is to determine the reliability and safety of neurophysiologic intraoperative monitoring in a group of children with Down syndrome undergoing neurosurgical spine procedures. METHODS: A total of six consecutive spinal procedures in six children with Down syndrome (three boys and three girls; mean age 10 years, range 4-16 years) were analyzed between January 1, 2008 and June 31, 2011. Somatosensory evoked potentials were stimulated at the ulnar nerve and tibial nerve for upper and lower extremities, respectively, and recorded at Erb's point and the scalp. Motor evoked potentials were elicited by transcranial electrical stimulation and recorded at the extensor carpi ulnaris muscle and tibialis anterior muscle for upper and lower extremities, respectively. A standardized anesthesia protocol for monitoring consisted of a titrated propofol drip combined with bolus dosing of fentanyl or sufentanil. RESULTS: Somatosensory and motor evoked potentials were documented at the beginning and end of the procedure in all six patients. Changes during the surgery were recorded. Five patients maintained somatosensory potentials throughout surgery. One patient demonstrated a >10% increase in latency or >50% decrease in amplitude suggesting spinal cord dysfunction. A mean baseline stimulation threshold for motor evoked potentials of 485 + 85 V (range 387-600 V) was used. Four patients maintained motor evoked potentials throughout surgery. One patient had loss of left lower somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) after rod placement; upon removal of the rod, SSEPs returned but not MEPs. Another patient did not have consistent MEPs on one side and had absent MEPs on the contralateral side throughout the case. Loss of MEPs in these two patients did not correlate with postoperative neurological status. There were no complications directly related to neurophysiologic intraoperative monitoring technique. CONCLUSIONS: Neurophysiologic intraoperative monitoring during neurosurgical procedures in children with Down syndrome may be reliably and safely implemented. Changes in neurophysiologic parameters during surgery must be carefully interpreted, and discussed with the neurosurgeon, neurophysiologist, and neuroanesthesiologist, and may not correlate with postoperative clinical changes. These changes may be related to abnormal physiology rather than an insult at the time of surgery. Nonetheless, the authors advocate routine neurophysiologic intraoperative monitoring in this special group of children undergoing neurosurgical spine procedures.

Reply to Bareille et al. Are Viscoelastometric Assays of Old Generation Ready for Disposal? Comment on "Volod et al. Viscoelastic Hemostatic Assays: A Primer on Legacy and New Generation Devices. J. Clin. Med. 2022, 11, 860".

We are pleased to see that Bareille et al. have written a Commentary: "Are viscoelastometric assays of old generation ready for disposal?" [...].

SHock-INduced Endotheliopathy (SHINE): A mechanistic justification for viscoelastography-guided resuscitation of traumatic and non-traumatic shock.

Irrespective of the reason for hypoperfusion, hypocoagulable and/or hyperfibrinolytic hemostatic aberrancies afflict up to one-quarter of critically ill patients in shock. Intensivists and traumatologists have embraced the concept of SHock-INduced Endotheliopathy (SHINE) as a foundational derangement in progressive shock wherein sympatho-adrenal activation may cause systemic endothelial injury. The pro-thrombotic endothelium lends to micro-thrombosis, enacting a cycle of worsening perfusion and increasing catecholamines, endothelial injury, de-endothelialization, and multiple organ failure. The hypocoagulable/hyperfibrinolytic hemostatic phenotype is thought to be driven by endothelial release of anti-thrombogenic mediators to the bloodstream and perivascular sympathetic nerve release of tissue plasminogen activator directly into the microvasculature. In the shock state, this hemostatic phenotype may be a counterbalancing, yet maladaptive, attempt to restore blood flow against a systemically pro-thrombotic endothelium and increased blood viscosity. We therefore review endothelial physiology with emphasis on glycocalyx function, unique biomarkers, and coagulofibrinolytic mediators, setting the stage for understanding the pathophysiology and hemostatic phenotypes of SHINE in various etiologies of shock. We propose that the hyperfibrinolytic phenotype is exemplified in progressive shock whether related to trauma-induced coagulopathy, sepsis-induced coagulopathy, or post-cardiac arrest syndrome-associated coagulopathy. Regardless of the initial insult, SHINE appears to be a catecholamine-driven entity which early in the disease course may manifest as hyper- or hypocoagulopathic and hyper- or hypofibrinolytic hemostatic imbalance. Moreover, these hemostatic derangements may rapidly evolve along the thrombohemorrhagic spectrum depending on the etiology, timing, and methods of resuscitation. Given the intricate hemochemical makeup and changes during these shock states, macroscopic whole blood tests of coagulative kinetics and clot strength serve as clinically useful and simple means for hemostasis phenotyping. We suggest that viscoelastic hemostatic assays such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are currently the most applicable clinical tools for assaying global hemostatic function-including fibrinolysis-to enable dynamic resuscitation with blood products and hemostatic adjuncts for those patients with thrombotic and/or hemorrhagic complications in shock states.

Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies.

Iatrogenic vascular air embolism is a relatively infrequent event but is associated with significant morbidity and mortality. These emboli can arise in many clinical settings such as neurosurgery, cardiac surgery, and liver transplantation, but more recently, endoscopy, hemodialysis, thoracentesis, tissue biopsy, angiography, and central and peripheral venous access and removal have overtaken surgery and trauma as significant causes of vascular air embolism. The true incidence may be greater since many of these air emboli are asymptomatic and frequently go undiagnosed or unreported. Due to the rarity of vascular air embolism and because of the many manifestations, diagnoses can be difficult and require immediate therapeutic intervention. An iatrogenic air embolism can result in both venous and arterial emboli whose anatomic locations dictate the clinical course. Most clinically significant iatrogenic air emboli are caused by arterial obstruction of small vessels because the pulmonary gas exchange filters the more frequent, smaller volume bubbles that gain access to the venous circulation. However, there is a subset of patients with venous air emboli caused by larger volumes of air who present with more protean manifestations. There have been significant gains in the understanding of the interactions of fluid dynamics, hemostasis, and inflammation caused by air emboli due to in vitro and in vivo studies on flow dynamics of bubbles in small vessels. Intensive research regarding the thromboinflammatory changes at the level of the endothelium has been described recently. The obstruction of vessels by air emboli causes immediate pathoanatomic and immunologic and thromboinflammatory responses at the level of the endothelium. In this review, we describe those immunologic and thromboinflammatory responses at the level of the endothelium as well as evaluate traditional and novel forms of therapy for this rare and often unrecognized clinical condition.

Computed-tomography-based anatomical study to assess feasibility of pedicle screw placement in the lumbar and lower thoracic pediatric spine.

PURPOSE: The anatomy of the pedicle is complex and three-dimensional; however, there are basic dimensions important for possible screw placement. There are relatively few studies examining the pedicle anatomy in children. This study was performed to evaluate the feasibility of pedicle screw placement in children aged 5-16, based on key anatomic dimensions. A case illustration is also provided. METHODS: The CT scans of 102 consecutive children were studied. Patients with abnormal anatomy were excluded. The parameters of the pedicle isthmus width (W), estimation of screw length (L), and axial angle (A) were recorded for 1,632 pedicles from T10 through L5. Patients were divided into four age groups. Statistical analysis was performed evaluating the difference between males and females and of the particular anatomy at the thoracolumbar junction. RESULTS: The pedicles increase in both L and W from T10-T12 and from L1-L5. L1 has a consistently smaller W compared to T12 in both genders over all age ranges. Estimating a W of 4.5 mm necessary for safe screw placement, we calculate that virtually all pedicles of T12 and L3-L5 are large enough for screw placement in both genders after age 8. L4 and L5 are large enough for screw placement in both genders in the youngest age range. CONCLUSIONS: Most of the pedicles of the lower lumbar spine and T12 are large enough to house the smallest commercially available screw. Understanding of the anatomy at the thoracolumbar junction is important, as the W of L1 is consistently smaller than T12.