Femoral nailing associated with bone marrow emboli in pigs induced a specific increase in blood IL-6 and broad inflammatory responses in the heart and lungs.

Introduction: Bone marrow embolization may complicate orthopedic surgery, potentially causing fat embolism syndrome. The inflammatory potential of bone marrow emboli is unclear. We aimed to investigate the inflammatory response to femoral intramedullary nailing, specifically the systemic inflammatory effects in plasma, and local tissue responses. Additionally, the plasma response was compared to that following intravenous injection of autologous bone marrow. Methods: Twelve pigs underwent femoral nailing (previously shown to have fat emboli in lung and heart), four received intravenous bone marrow, and four served as sham controls. Blood samples were collected hourly and tissue samples postmortem. Additionally, we incubated bone marrow and blood, separately and in combination, from six pigs in vitro. Complement activation was detected by C3a and the terminal C5b-9 complement complex (TCC), and the cytokines TNF, IL-1ß, IL-6 and IL-10 as well as the thrombin-antithrombin complexes (TAT) were all measured using enzyme-immunoassays. Results: After nailing, plasma IL-6 rose 21-fold, compared to a 4-fold rise in sham (p=0.0004). No plasma differences in the rest of the inflammatory markers were noted across groups. However, nailing yielded 2-3-times higher C3a, TCC, TNF, IL-1ß and IL-10 in lung tissue compared to sham (p<0.0001-0.03). Similarly, heart tissue exhibited 2-times higher TCC and IL-1ß compared to sham (p<0.0001-0.03). Intravenous bone marrow yielded 8-times higher TAT than sham at 30 minutes (p<0.0001). In vitro, incubation of bone marrow for four hours resulted in 95-times higher IL-6 compared to whole blood (p=0.03). Discussion: A selective increase in plasma IL-6 was observed following femoral nailing, whereas lung and heart tissues revealed a broad local inflammatory response not reflected systemically. In vitro experiments may imply bone marrow to be the primary IL-6 source.

[Post-traumatic stroke due to fat embolism]. / Accident vasculaire cérébral post-traumatique sur embolie graisseuse.

Fat embolism syndrome mainly occurs following trauma to the long bones or pelvis. Non-traumatic causes are rarer. Its incidence varies greatly and depends on the number of fractures involved. Two physiopathological theories, one mechanical and the other biochemical, attempt to explain this still poorly understood phenomenon. The complete form of the syndrome results in a combination of pulmonary involvement, neurological disorders and a petechial rash. Given the polymorphism of signs and symptoms, Fat embolism syndrome remains a diagnosis of exclusion. Regarding treatment, the therapeutic strategy combines treatment of the causative process with conservative measures.

Le syndrome d'embolie graisseuse se manifeste majoritairement dans les suites d'un traumatisme des os longs ou du bassin. Les causes non traumatiques sont plus rares. Son incidence varie fortement et dépend du nombre de fractures impliquées. Deux théories physiopathologiques, l'une mécanique et l'autre biochimique, tentent d'expliquer ce phénomène encore mal compris. La forme complète du syndrome se traduit par la combinaison d'une atteinte pulmonaire, de troubles neurologiques et d'une éruption pétéchiale. Étant donné le polymorphisme des signes et des symptômes, le syndrome d'embolie graisseuse reste un diagnostic d'exclusion. Concernant le traitement, la stratégie thérapeutique associe la prise en charge du processus causal combinée à des mesures conservatrices.

Trends and associated outcomes of fat embolism after trauma surgery.

BACKGROUND: Fat embolism is a life-threatening complication often occurring in patients with traumatic injuries. However, temporal trends and perioperative outcomes of fat embolism remain understudied. Using a nationally representative cohort, we aimed to characterize temporal trends of fat embolism and its associated resource utilization in operatively managed trauma patients. METHODS: All patients (≥18 years) undergoing any major operations after traumatic injuries were tabulated using the 2005 to 2020 National Inpatient Sample. Patients were stratified into those with fat embolism and those without. Multivariable logistic and linear regressions were developed to assess the association between fat embolism and outcomes of interest. RESULTS: Of an estimated 10,600,000 hospitalizations, 7,479 (0.07%) patients had fat embolism. Compared to the non-fat embolism cohort, the fat embolism cohort was younger (55 [26-79] vs 69 [49-82] years, standard mean difference = 0.46) and more likely to receive treatment at a high-volume trauma center (42.9 vs 33.7%, standard mean difference = 0.19). Over the study period, there was an increase in annual mortality and hospitalization costs among the fat embolism group (nptrend <0.001). After risk adjustment, fat embolism was associated with greater odds of mortality (adjusted odds ratio: 2.65, 95% confidence interval: 2.24-3.14) compared to others. Additionally, fat embolism was associated with increased odds of cerebrovascular, infectious, and renal complications. CONCLUSION: Among all operatively managed trauma patients, those who developed fat embolism had increased mortality, rates of complications, length of stay, and costs. Optimization of early and accurate identification of fat embolism is warranted to mitigate complications and improve resource allocation among trauma patients.

Peripheral blood smear - An expeditious test in the preliminary diagnosis of bone marrow embolism in a case of multiple fractures: A case report.

ABSTRACT: Bone marrow embolism is known to occur after fractures of long bones such as the femur and pelvis. We report a case of multiple fractures in a 32-year-old female patient, demonstrating bone marrow elements in the peripheral blood as early as 2 hours after trauma. This is the first case being reported with an ante-mortem demonstration of circulating marrow emboli in the peripheral blood, while the previously reported cases have demonstrated the emboli in post-mortem examination. A careful correlation of the clinical history of trauma, hematology auto-analyzer results, and the presence of bone marrow particles and fat globules in peripheral blood helped in arriving at the diagnosis of fat embolism in our case irrefutably.

Fat embolism: the hidden murder for trauma patients!

INTRODUCTION: fat embolism syndrome (FES) is an acute respiratory disorder that occurs when an inflammatory response causes the embolization of fat and marrow particles into the bloodstream. The exact incidence of FES is not well defined due to the difficulty of diagnosis. FES is mostly associated with isolated long bone trauma, and it is usually misdiagnosed in other trauma cases. The scope of this study was to identify and search the current literature for cases of FES in nonorthopedic trauma patients with the aim of defining the etiology, incidence, and main clinical manifestations. METHODS: we perform a literature search via the PubMed journal to find, summarize, and incorporate reports of fat embolisms in patients presenting with non-orthopedic trauma. RESULTS: the final literature search yielded 23 papers of patients presenting with fat embolism/FES due to non-orthopedic trauma. The presentation and etiology of these fat embolisms is varied and complex, differing from patient to patient. In this review, we highlight the importance of maintaining a clinical suspicion of FES within the trauma and critical care community. CONCLUSION: to help trauma surgeons and clinicians identify FES cases in trauma patients who do not present with long bone fracture, we also present the main clinical signs of FES as well as the possible treatment and prevention options.

Cerebral fat embolism with turbid urine as the initial sign.

BACKGROUND: Cerebral fat embolism (CFE) is a rare but potentially fatal complication that can occur after long bone fractures. It represents one subcategory of fat embolisms (FE). Diagnosing CFE can be challenging due to its variable and nonspecific clinical manifestations. We report a case of CFE initially presenting with turbid urine, highlighting an often neglected sign. CASE PRESENTATION: A 69-year-old male was admitted after a traffic accident resulting in bilateral femoral fractures. Sixteen hours post-admission, grossly turbid urine was noted but received no special attention. Four hours later, he developed rapid deterioration of consciousness and respiratory distress. Neurological examination revealed increased upper limb muscle tone and absent voluntary movements of lower limbs. Brain MRI demonstrated a 'starfield pattern' of diffuse punctate lesions, pathognomonic for CFE. Urine microscopy confirmed abundant fat droplets. Supportive treatment and fracture fixation were performed. The patient regained consciousness after 3 months but had residual dysphasia and limb dyskinesia. CONCLUSION: CFE can present with isolated lipiduria preceding overt neurological or respiratory manifestations. Heightened awareness of this subtle sign in high-risk patients is crucial for early diagnosis and intervention. Prompt urine screening and neuroimaging should be considered when gross lipiduria occurs after long bone fractures.

Severe Hemodynamic Collapse During Humerus Stabilization with Photodynamic Implant: A Report of Two Cases.

CASE: We present 2 cases of severe hemodynamic collapse during prophylactic stabilization of impending pathologic humerus fractures using a photodynamic bone stabilization device. Both events occurred when the monomer was infused under pressure into a balloon catheter. CONCLUSION: We suspect that an increase in intramedullary pressure during balloon expansion may cause adverse systemic effects similar to fat embolism or bone cement implantation syndrome. Appropriate communication with the anesthesia team, invasive hemodynamic monitoring, and prophylactic vent hole creation may help mitigate or manage these adverse systemic effects.

Pulmonary fat embolism in non-survivors after cardiopulmonary resuscitation.

BACKGROUND: Blunt trauma acting against the human body presents the fundamental cause of pulmonary fat embolism (PFE) and fat embolism syndrome. The aim of the present study was to investigate PFE in non-survivors after cardiopulmonary resuscitation (CPR). METHODS: This was a prospective cohort study conducted in University Hospital Ostrava, Czech Republic. Within a 4-year study period, all non-survivors after CPR because of out-of-hospital cardiac arrest were assessed for the study eligibility. The presence/seriousness of PFE was determined by microscopic examination of cryo-sections of lung tissue (staining with Oil Red O). RESULTS: In total, 106 persons after unsuccessful CPR were enrolled in the study. The most frequent cause of death in the study population (63.2% of cases) was cardiac disease (ischemic heart disease); PFE was not determined as the cause of death in any of our study cases. Sternal fractures were identified 66.9%, rib fractures (usually multiple) in 80.2% of study cases; the median number of rib fractures was 10.2 fractures per person. Serious intra-thoracic injuries were found in 34.9% of cases. Microscopic examination of lung cryo-sections revealed PFE in 40 (37.7%) study cases; PFE was most frequently evaluated as grade I or II. Occurrence of sternal and rib fractures was significantly higher in persons with PFE than between persons without PFE (p = 0.033 and p = <0.001). Number of rib fractures was also significantly higher in persons with PFE. The occurrence of serious intra-thoracic injuries was comparable in both our study groups (p = 0.089). CONCLUSIONS: PFE presents a common resuscitation injury which can be found in more than 30% of persons after CPR. Persons with resuscitation skeletal chest fractures have significantly higher risk of PFE development. During autopsy of persons after unsuccessful CPR, it is necessary to distinguish CPR-associated injuries including PFE from injuries that arise from other mechanisms.

[Clinical manifestation and imaging diagnostic analysis of fat embolism syndrome].

OBJECTIVE: To explore characteristics of clinical and imaging findings in patients with fat embolism syndrome. METHODS: From January 2021 to October 2022,clinical manifestations of 13 patients with fat embolism due to fracture or orthopaedic surgery were retrospectively analyzed,including 11 males and 2 females,aged from 17 to 60 years old. Mental and respiratory abnormalities and changes in vital signs occurred after admission or after surgery,and patient's chest and brain imaging results were abnormal. The patient's mental and respiratory abnormalities,vital signs,chest and brain imaging results were continuously monitored. RESULTS: The main clinical manifestations of fat embolism syndrome were abnormal pulmonary respiration in 13 patients,abnormal central nervous function in 7 patients,and spotted rash in 2 patients. Chest CT showed diffuse distribution of ground glass shadows in 13 patients,and severe symptoms were "snowstorm". Nine patients with ground glass fusion consolidation,5 patients with multiple nodules and 4 patients accompanied by bilateral pleural effusion. Head CT findings of 5 patients were negative,and head MRI findings of 1 patient showed multiple T1WI low signal,T2WI high signal shadow,DWI high signal shadow,and "starry sky sign" in basal ganglia,radiative crown,hemioval center,thalamus,frontal parietal cortex and subcortex. CONCLUSION: Fat embolism syndrome has a high mortality rate. Clinical manifestations of respiratory system and nervous system are not specific,and the skin spot rash has a characteristic manifestation. The "blizzard" sign is the specific manifestation of chest X-ray and CT examination of fat embolism,and the "starry sky" sign is the typical manifestation of diffusion-weighted sequence of brain MRI examination of fat embolism.

Fat embolism syndrome associated with atraumatic compartment syndrome of the bilateral upper extremities: An unreported etiology.

Fat embolism syndrome (FES) is a potentially life-threatening condition that develops when fat embolism leads to clinical symptoms and multisystem dysfunction. The classic triad of respiratory distress, neurologic symptoms, and petechial rash are non-specific, and the lack of specific laboratory tests makes the diagnosis of FES difficult. Although FES is most common after long bone fractures, multiple conditions some of which are atraumatic have been associated with the development of FES. We report a case of FES that occurred in the setting of a non-traumatic compartment syndrome of the upper extremities. The pathologic and clinical findings, pathophysiology, diagnostic challenges, and pathologic methods to properly diagnose FES are discussed with a review of the relevant literature. This case highlights the importance of the autopsy in making a diagnosis of FES in cases where death could otherwise be incorrectly attributed to multi-organ system failure, shock, or sepsis.

In vivo study to assess fat embolism resulting from the Reamer-Irrigator-Aspirator 2 system compared to a novel aspirator-based concept for intramedullary bone graft harvesting.

INTRODUCTION: Fat embolism (FE) following intramedullary (IM) reaming can cause severe pulmonary complications and sudden death. Recently, a new harvesting concept was introduced in which a novel aspirator is used first for bone marrow (BM) aspiration and then for subsequent aspiration of morselized endosteal bone during sequential reaming (A + R + A). In contrast to the established Reamer-Irrigator-Aspirator (RIA) 2 system, the new A + R + A concept allows for the evacuation of fatty BM prior to reaming. In this study, we hypothesized that the risk of FE, associated coagulopathic reactions and pulmonary FE would be comparable between the RIA 2 system and the A + R + A concept. MATERIALS AND METHODS: Intramedullary bone graft was harvested from intact femora of 16 Merino sheep (age: 1-2 years) with either the RIA 2 system (n = 8) or the A + R + A concept (n = 8). Fat intravasation was monitored with the Gurd test, coagulopathic response with D-dimer blood level concentration and pulmonary FE with histological evaluation of the lungs. RESULTS: The total number and average size of intravasated fat particles was similar between groups (p = 0.13 and p = 0.98, respectively). D-dimer concentration did not significantly increase within 4 h after completion of surgery (RIA 2: p = 0.82; A + R + A: p = 0.23), with an interaction effect similar between groups (p = 0.65). The average lung area covered with fat globules was similar between groups (p = 0.17). CONCLUSIONS: The use of the RIA 2 system and the novel A + R + A harvesting concept which consists of BM evacuation followed by sequential IM reaming and aspiration of endosteal bone, resulted in only minor fat intravasation, coagulopathic reactions and pulmonary FE, with no significant differences between the groups. Our results, therefore, suggest that both the RIA 2 system and the new A + R + A concept are comparable technologies in terms of FE-related complications.

Cerebral fat emboli in a patient with paraplegia caused by bilateral femur fractures.

Cerebral fat embolism is a rare cause of stroke and therefore an overlooked diagnosis. Often it is seen as a consequence of major bone fractures or after arthroplasty, and can lead to respiratory or circulatory collapse. We present a case of a patient with a history of paraplegia after a thoracic spinal cord injury that developed cerebral fat embolism following a bilateral femur fracture. Since the patient was paraplegic and with an altered mental state upon admission, femoral bone fractures were not initially suspected. The case shows the difficulties in diagnosing this condition.

A diagnostic strategy for pulmonary fat embolism based on routine H&E staining using computational pathology.

Pulmonary fat embolism (PFE) as a cause of death often occurs in trauma cases such as fractures and soft tissue contusions. Traditional PFE diagnosis relies on subjective methods and special stains like oil red O. This study utilizes computational pathology, combining digital pathology and deep learning algorithms, to precisely quantify fat emboli in whole slide images using conventional hematoxylin-eosin (H&E) staining. The results demonstrate deep learning's ability to identify fat droplet morphology in lung microvessels, achieving an area under the receiver operating characteristic (ROC) curve (AUC) of 0.98. The AI-quantified fat globules generally matched the Falzi scoring system with oil red O staining. The relative quantity of fat emboli against lung area was calculated by the algorithm, determining a diagnostic threshold of 8.275% for fatal PFE. A diagnostic strategy based on this threshold achieved a high AUC of 0.984, similar to manual identification with special stains but surpassing H&E staining. This demonstrates computational pathology's potential as an affordable, rapid, and precise method for fatal PFE diagnosis in forensic practice.

Fat embolism syndrome in Duchenne muscular dystrophy: Report on a novel case and systematic literature review.

We report a non-ambulatory 13-year-old boy with Duchenne muscular dystrophy who experienced severe acute respiratory distress syndrome and cerebral fat embolism following elective soft tissue surgery. Post-surgery radiological examination revealed bilateral femoral fractures and marked osteopenia that were believed to have caused disseminated pulmonary and cerebral fat embolism. The patient had never been on glucocorticoid treatment. Five months post-surgery, he remained in a state of minimal consciousness. A literature review was performed and eleven publications included, providing case reports of a total number of 23 patients with Duchenne muscular dystrophy with fat embolism syndrome. The most common causes were falls from the wheelchair that predominantly resulted in femoral fractures. Median age at the event was around 14 years. Seven patients succumbed to complications of fat embolism. No event was described in the context of surgery. We want to raise awareness that spontaneous unnoticed fractures may occur especially in adolescents with DMD from traumatic injury of large bones and also during elective surgery with a high risk of causing fat embolism with severe sequelae.

Augmented Safety Profile of Ultrasound-Guided Gluteal Fat Transfer: Retrospective Study With 1815 Patients.

BACKGROUND: Gluteal augmentation with autologous fat transfer is one of the fastest growing aesthetic surgical procedures worldwide over the past decade. However, this procedure can be associated with high mortality from fatal pulmonary fat embolism events caused by intramuscular injection of fat. Ultrasound-guided fat grafting allows visualization of the transfer in the subcutaneous space, avoiding intramuscular injection. OBJECTIVES: The aim of this study was to assess the safety and efficacy of gluteal fat grafting performed with ultrasound-guided cannulation. METHODS: A retrospective chart review of all patients undergoing ultrasound-guided gluteal fat grafting at the authors' center between 2019 and 2022 was performed. All cases were performed by board-certified and board-eligible plastic surgeons under general anesthesia in ASA Class I or II patients. Fat was only transferred to the subcutaneous plane when over the gluteal muscle. Patients underwent postoperative follow-up from a minimum of 3 months up to 2 years. Results were analyzed with standard statistical tests. RESULTS: The study encompassed 1815 female patients with a median age of 34 years. Controlled medical comorbidities were present in 14%, with the most frequent being hypothyroidism (0.7%), polycystic ovarian syndrome (0.7%), anxiety (0.6%), and asthma (0.6%). Postoperative complications occurred in 4% of the total cohort, with the most common being seroma (1.2%), local skin ischemia (1.2%), and surgical site infection (0.8%). There were no macroscopic fat emboli complications or mortalities. CONCLUSIONS: These data suggest that direct visualization of anatomic plane injection through ultrasound guidance is associated with a low rate of complications. Ultrasound guidance is an efficacious adjunct to gluteal fat grafting and is associated with an improved safety profile that should be considered by every surgeon performing this procedure.

Síndrome de embolia grasa secundario a fracturas de huesos cortos: Presentación de casos / Fat embolism syndrome secondary to short bone fracture. Case presentation

Introducción: Se presenta el caso clínico de un varón de 15 años con fracturas de huesos cortos del pie derecho como consecuencia de un accidente de tránsito. Tras 24 h de evolución, ingresa con disnea, desaturación, pico febril objetivo y posterior desarrollo de insuficiencia respiratoria. Ante la sospecha clínica de síndrome de embolia grasa, se solicita una angiotomografía pulmonar que confirma el diagnóstico. Se trata de una entidad inusual en pacientes con este tipo de fractura. El tratamiento inicial consistió en vigilancia estrecha en la unidad de cuidados intensivos, medidas de soporte con oxígeno suplementario, terapia res-piratoria y manejo quirúrgico de las fracturas. La evolución clínica del paciente fue adecuada y el cuadro respiratorio se resolvió por completo. Conclusiones: El síndrome de embolia grasa secundario a fracturas de huesos cortos es un cuadro infrecuente; por lo tanto, es preciso tener un alto grado de sospecha diagnóstica, no solo en los escenarios más comunes, sino también en este tipo de contextos inusuales y retadores, que permita su identificación temprana y, de esta forma, implementar un manejo oportuno y generar un impacto favorable en los desenlaces clínicos y en la disminución del riesgo de secuelas a largo plazo. Nivel de Evidencia: IV

Introduction: We present the clinical case of a 15-year-old male who sustained fractures to the short bones of his right foot as a result of a traffic accident. After 24 hours of evolution, he was admitted for dyspnea, desaturation, an objective febrile peak, and the development of respiratory failure. Given the clinical suspicion of fat embolism syndrome, pulmonary angiotomography was requested, which confirmed the diagnosis. This is a rare finding in patients with this type of fracture. The initial treatment included close monitoring in the intensive care unit, supportive measures such as supplemental oxygen, respiratory therapy, and surgical fracture management. The patient's clinical progression was adequate, and the respiratory condition resolved completely. Conclusion: Fat embolism syndrome resulting from short bone fractures is a rare condition; therefore, it is necessary to have a high level of diagnostic suspicion, not only in the most common scenarios, but also in these unusual and challenging contexts, which allows for its early detection and, as a result, timely management, which has a positive impact on clinical outcomes and reduces the risk of long-term sequelae. Level of Evidence: IV