The Spine Journal 14 (2014) e1–e5
Case Report
Fat embolism syndrome following percutaneous vertebroplasty: a case report Hasib Ahmadzai, MBBS (Hons I), BSc (Med) Hons Ia,b,*, Scott Campbell, MBBS (Hons)a,b, Constantine Archis, MBBS (Hons), FRACPa,b, William A. Clark, MBBS, MD, FRANZCRc a
Faculty of Medicine, University of New South Wales, Level 2, ASGM Building/Botany St, Sydney, New South Wales 2052, Australia b Department of Respiratory Medicine, St. George Hospital, Gray St, Kogarah, New South Wales 2217, Australia c Department of Radiology, St. George Private Hospital, 1 South St, Department of Radiology, Kogarah, New South Wales 2217, Australia Received 18 April 2013; revised 25 August 2013; accepted 19 September 2013
Abstract
BACKGROUND CONTEXT: Vertebroplasty is commonly performed for management of pain associated with vertebral compression fractures. There have been two previous reports of fatal fat embolism following vertebroplasty. Here we describe a case of fat embolism syndrome following this procedure, and also provide fluoroscopic video evidence consistent with this occurrence. PURPOSE: The purpose of this study was to review the literature and report a case of fat embolism syndrome in a patient who underwent percutaneous vertebroplasty for compression fracture. STUDY DESIGN/SETTING: The study design for this manuscript was of a clinical case report. METHODS: A 68-year-old woman who developed sudden back pain with minimal trauma was found to have a T6 vertebral compression fracture on radiographs and bone scans. Percutaneous vertebroplasty of T5 and T6 was performed. RESULTS: Fluoroscopic imaging during the procedure demonstrated compression and rarefaction of the fractured vertebra associated with changes in intrathoracic pressure. Immediately after the procedure, the patient’s back pain resolved and she was discharged home. Two days later, she developed increasing respiratory distress, confusion, and chest pain. A petechial rash on her upper arms also appeared. No evidence of bone cement leakage or pulmonary filling defects were seen on computed tomography-pulmonary angiography. Brain magnetic resonance imaging demonstrated hyperintensities in the periventricular and subcortical white matter on T2/fluid-attenuated inversion recovery sequences. A diagnosis of fat embolism syndrome was made, and the patient recovered with conservative management. CONCLUSIONS: Percutaneous vertebroplasty is a relatively safe and simple procedure, reducing pain and improving functional limitations in patients with vertebral fractures. This case demonstrates an uncommon yet serious complication of fat embolism syndrome. Clinicians must be aware of this complication when explaining the procedure to patients and provide prompt supportive care when it does occur. Ó 2014 Elsevier Inc. All rights reserved.
Keywords:
Percutaneous vertebroplasty; Fat embolism; Vertebral fracture; Polymethylmethacrylate
Introduction Percutaneous vertebroplasty is a relatively successful interventional radiological procedure introduced in 1984 [1]. It involves injection of acrylic bone cement (usually polymethylmethacrylate [PMMA]) into a vertebral body, FDA device/drug status: Not applicable. Author disclosures: HA: Nothing to disclose. SC: Nothing to disclose. CA: Nothing to disclose. WAC: Nothing to disclose. * Corresponding author. Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia. Tel.: 61-4-394-784-30. E-mail address: [email protected] (H. Ahmadzai) 1529-9430/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.spinee.2013.09.021
providing pain relief and bone stabilization. It is used commonly to treat vertebral osteoporotic fractures, osteolytic lesions from vertebral metastases, aggressive hemangioma, and multiple myeloma [2,3]. Complications occur infrequently but include local bleeding, infection, cement leakage into the spinal canal, paravertebral tissues, and perivertebral venous system, leading to cord or nerve root compression as well as pulmonary embolism from PMMA or bone marrow contents [4]. This report highlights a case of fat embolism syndrome following percutaneous vertebroplasty for an osteoporotic fracture in a woman who had been treated with prednisone for systemic lupus erythematosus
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H. Ahmadzai et al. / The Spine Journal 14 (2014) e1–e5
(SLE). It also displays dynamic fluoroscopic evidence showing the role of vertebral compression fractures in causing fat embolism.
Case report A 68-year-old obese woman suffering from a 2-week history of severe thoracic back pain after an osteoporotic compression fracture of the T6 vertebra secondary to steroid use was admitted for outpatient percutaneous vertebroplasty. Her background medical history included cerebral vasculitis related to SLE, for which she was taking prednisone (10 mg/day), mycophenolate, and clopidogrel. Brain magnetic resonance imaging (MRI) performed 1 year previously did not identify active vasculitis or any other abnormalities. She also had hypertension, hypercholesterolemia, and also took propranolol, fosinopril, atorvastatin, Caltrate, and cholecalciferol. The vertebroplasty was performed under local anesthetic. The T5- and T6-level procedures were accessed using a 13-gauge trocar placed via a left transpedicular approach. Fluoroscopic imaging at the time revealed respirationinduced compression and rarefaction movement of the fractured vertebra (Supplementary Video). The patient was noted to be dyspneic before the procedure, although denied underlying respiratory disease. Polymethylmethacrylate was injected into each vertebral body, using 7 mL at T6 and 5 mL at T5 with adequate filling achieved (Fig. 1). The patient remained stable throughout the procedure. She was given ceftriaxone for infection prophylaxis, and because she had no additional respiratory symptoms and was otherwise well, she was subsequently discharged. Two days after the procedure she presented to the emergency department with progressive confusion, rigors, and chest pain on deep inspiration. She had also become increasingly short of breath 1 day after the procedure but denied headache or visual changes. On examination she appeared centrally cyanosed and was disorientated. Her oxygen saturation was 84% on room air; respiratory rate, 28 breaths/minute; heart rate, 125 beats/minute; blood pressure, 120/80 mmHg; and temperature, 38.2 C. The rest of the examination and chest radiograph were unremarkable. Electrocardiography showed sinus tachycardia but no ischemic changes. Arterial blood gases indicated hypoxemia, with arterial oxygen pressure of 60.1 mmHg. Full blood count, urea, electrolytes, creatinine, and liver function tests were normal, although she had a C-reactive protein value of 107 mg/L (normal, !3 mg/L) and a mildly elevated D-dimer level of 0.8 mg/mL (normal, !0.5 mg/mL). Computed tomography-pulmonary angiogram did not identify any filling defects within the pulmonary arteries and there was no evidence of paravertebral or pulmonary cement leakage (Fig. 2). Brain MRI was performed the following day, which identified nodular T2/fluid-attenuated inversion recovery hyperintensities in the periventricular and
Fig. 1. Lateral fluoroscopic view of T5 and T6 vertebrae after cement injection. Refer to online supplementary data for a video of the procedure.
subcortical white matter bilaterally, with no acute areas of infarct observed in the corresponding magnetic resonance diffusion-weighted images (Fig. 3). This had the appearance of longstanding possible microvascular ischemia or cerebral vasculitis, although MRI performed 12 months previously showed no such changes. No follow-up MRI had been performed. Three days after the procedure, a bilateral dermal petechial rash on the extensor surface of the patient’s forearms and lower arms appeared. Taken together with the other clinical features, a diagnosis of fat embolism syndrome (FES) was made. The patient was initiated on 50 mg prednisone and given high-flow oxygen on admission, and her symptoms improved. She was kept in the hospital for observation, with resolution of all symptoms within 1 week. She remained well at the clinical follow-up.
Discussion The first clinical diagnosis of FES was made in a patient with a fractured femur in 1873. The widely accepted guidelines for the clinical diagnosis of FES were proposed by Gurd and Wilson [5] (Table); however, the classic triad of acute respiratory distress, altered mental status, and
H. Ahmadzai et al. / The Spine Journal 14 (2014) e1–e5
e3
Fig. 2. (Left, Middle) Computed tomographic pulmonary angiogram indicating no filling defects from a pulmonary embolism. (Right) Computed tomographic findings 2 days after vertebroplasty.
petechial rash is seen in only one-third of cases [6]. Fat embolism occurs most commonly after orthopedic trauma, although it can also occur in the setting of many medical conditions and as a surgical complication [7]. Patients undergoing vertebroplasty on multiple levels during the 1 session appear to be at greater risk [8], with two fatalities after this procedure reported in the literature [9–11]. Interestingly, there have also been two cases of patients who died of fat embolism after isolated vertebral compression fracture in whom no surgical interventions were performed [12,13]. Two theories exist regarding the development of clinical features in FES. The first postulates that large fat droplets released into the systemic circulation following raised intravertebral pressure obstruct end capillary beds mechanically. Hypoxemia and tachycardia are seen in more than 90% of cases [14] reflecting this obstruction within the pulmonary circulation [9,15,16]. Changes in cardiorespiratory parameters have been demonstrated in studies immediately after cement injection in sheep vertebroplasty, with fat
emboli demonstrated histologically [15–19]. The second theory hypothesis that released fat particles trigger a localized inflammatory reaction. This is evidenced by delayed onset of clinical features and development of nontraumatic FES [7]. The delayed clinical and radiological appearance of FES closely resembles acute respiratory distress syndrome [20], with vasoactive mediator release and fatty acid precipitation in response to trauma and inflammatory conditions [10]. Given our patient’s history of SLE and vasculitis, an inflammatory predisposition may explain why the syndrome develops in a small percentage of cases despite evidence of release of fat emboli following vertebroplasty. No studies have investigated this association, although atraumatic fat embolism has been described in the setting of SLE. In SLE immune complex deposition, coagulation abnormalities and lipid mobilization may also be important for FES development [21]. The T2/fluid-attenuated inversion recovery brain MRI hyperintensities were most likely the result of cerebral
Fig. 3. Axial magnetic resonance imaging brain T2/fluid-attenuated inversion recovery sequence (Left) indicating hyperintensities (arrows) in the paraventricular and subcortical white matter that were not apparent on the corresponding diffusion-weighted imaging sequence (Right).
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H. Ahmadzai et al. / The Spine Journal 14 (2014) e1–e5
Table Gurd and Wilson criteria for the diagnosis of fat embolism syndrome Major criteria
Minor criteria
Petechiae in a vest distribution and on arms Hypoxemia with PaO2 !60 mmHg, FiO2 #40% Central nervous system depression disproportionate to hypoxemia Pulmonary edema
Tachycardia, heart rate O110 beats/minute Pyrexia (temperature, O38.5 C) Emboli visible in retina Lipiduria Fat in sputum Unexplained drop in hematocrit or platelet count Increasing erythrocyte sedimentation rate
Conclusions We report a case of FES in a patient following percutaneous vertebroplasty, a procedure being used increasingly to treat painful osteoporotic fractures. Fat embolism syndrome exists as an uncommon but potentially fatal complication of this procedure. It is important to consider this complication after vertebral fractures and vertebroplasty, as with other orthopedic trauma and surgery. Treatment remains supportive. New studies suggest that augmenting the current technique by removing marrow and reducing intramedullary pressure during the procedure may reduce the risk of developing this complication, particularly in those with underlying disease.
FiO2, percentage inspired oxygen; PaO2, arterial oxygen pressure.
vasculitis; however, cerebral fat embolism does occur in some cases and may lead to focal neurologic deficits. This occurs as a result of fat emboli originating from the venous circulation and entering and obstructing a systemic artery. Paradoxical FES can occur as a result of a patent foramen ovale, atrial or ventricular septal defect, persistent truncus arteriosus, or arteriovenous malformations [22]. It is important to note that patent foramen ovale is present in up to ~27% of the general adult population and is usually asymptomatic [23], but is an important cause of paradoxical embolism, which may account for most cases of cerebral fat emboli. Transesophageal echocardiography had not been performed in our patient’s case to confirm this. The mental state changes observed in this condition are, however, usually the result of hypoxia and not necessarily cerebral fat emboli. A major role of vertebroplasty has been the fixation of painful osteoporotic vertebral fractures. Osteoporotic vertebrae contain a greater proportion of intramedullary fat, leading to extravasation of more marrow content into the pulmonary and cerebral circulation when fractured [15]. Augmenting vertebroplasty, such as with vent-hole drilling to reduce intramedullary pressure and pulsed-jet lavage to remove marrow content before cement injection, has been suggested in recent sheep studies as a way to minimize this [19,24]. This allowed for greater PMMA injection without increasing intravascular fat emboli on histopathological examination of the lungs [24]. This may be investigated through clinical trials, with a potential role to reduce the risk of FES in patients with underlying cardiorespiratory or inflammatory conditions. Supportive care remains the basis of treatment for FES, with early recognition and aggressive hemodynamic and ventilatory support [7]. The role of corticosteroids remains unclear, with two recent systematic reviews suggesting some prophylactic benefit, although no dosing threshold was given [25,26]. Nevertheless, the use of high-flow oxygen and increased prednisone dose probably helped our patient recover from fat embolism. The efficacy of other therapies such as albumin infusion and pulmonary vasodilators has yet to be proved [27].
Appendix Supplementary material Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.spinee.2013.09.021. References [1] Galibert P, Deramond H, Rosat P, Le Gars D. Preliminary report on the percutaneous vertebroplasty with acrylic cement as a treatment of vertebral hemangioma. Neurochirurgie 1987;33:166–8. [2] Diamond TH, Bryant C, Browne L, Clark WA. Clinical outcomes after acute osteoporotic vertebral fractures: a 2-year non-randomised trial comparing percutaneous vertebroplasty with conservative therapy. Med J Aust 2006;184:113–7. [3] Diamond TH, Hartwell T, Clarke W, Manoharan A. Percutaneous vertebroplasty for acute vertebral body fracture and deformity in multiple myeloma: a short report. Br J Haematol 2004; 124:485–7. [4] Laredo JD, Hamze B. Complications of percutaneous vertebroplasty and their prevention. Skeletal Radiol 2004;33:493–505. [5] Gurd AR, Wilson RI. The fat embolism syndrome. J Bone Joint Surg Br 1974;56B:408–16. [6] Talbot M, Schemitsch EH. Fat embolism syndrome: history, definition, epidemiology. Injury 2006;37(4 Suppl):S3–7. [7] Glazer JL, Onion DK. Fat embolism syndrome in a surgical patient. J Am Board Fam Pract 2001;14:310–3. [8] Childers JC Jr. Cardiovascular collapse and death during vertebroplasty. Radiology 2003;228:902. [9] Chen HL, Wong CS, Ho ST, et al. A lethal pulmonary embolism during percutaneous vertebroplasty. Anesth Analg 2002;95: 1060–2. [10] Syed MI, Jan S, Patel NA, et al. Fatal fat embolism after vertebroplasty: identification of the high-risk patient. AJNR Am J Neuroradiol 2006;27:343–5. [11] Temple JD, Ludwig SC, Ross WK, et al. Catastrophic fat embolism following augmentation of pedicle screws with bone cement: a case report. J Bone Joint Surg Am 2002;84-A:639–42. [12] Lastra RR, Saldanha V, Balasubramanian M, Handal J. Fatal fat embolism in isolated vertebral compression fracture. Eur Spine J 2010;19(2 Suppl):S200–2. [13] Lewis D, Jones R, Carpenter C, James S. Fatal fat embolism following an isolated vertebral fracture. Acta Orthop Belg 2007;73: 137–9. [14] Bulger EM, Smith DG, Maier RV, Jurkovich GJ. Fat embolism syndrome: a 10-year review. Arch Surg 1997;132:435–9.
H. Ahmadzai et al. / The Spine Journal 14 (2014) e1–e5 [15] Aebli N, Krebs J, Davis G, et al. Fat embolism and acute hypotension during vertebroplasty: an experimental study in sheep. Spine 2002;27:460–6. [16] Aebli N, Krebs J, Schwenke D, et al. Pressurization of vertebral bodies during vertebroplasty causes cardiovascular complications: an experimental study in sheep. Spine 2003;28:1513–20. [17] Krebs J, Ferguson SJ, Hoerstrup SP, et al. Influence of bone marrow fat embolism on coagulation activation in an ovine model of vertebroplasty. J Bone Joint Surg Am 2008;90:349–56. [18] Aebli N, Schwenke D, Davis G, et al. Polymethylmethacrylate causes prolonged pulmonary hypertension during fat embolism. Acta Orthop 2005;76:904–11. [19] Aebli N, Krebs J, Schwenke D, et al. Cardiovascular changes during multiple vertebroplasty with and without vent-hole: an experimental study in sheep. Spine 2003;28:1504–12. [20] Porpodis K, Karanikas M, Zarogoulidis P, et al. Fat embolism due to bilateral femoral fracture: a case report. Int J Gen Med 2012;5:59–63. [21] Katz DA, Ben-Ezra J, Factor SM, et al. Fatal pulmonary and cerebral fat embolism in systemic lupus erythematosus. JAMA 1983;250:2666–9.
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[22] Mueller F, Pfeifer C, Kinner B, et al. Post-traumatic fulminant paradoxical fat embolism syndrome in conjunction with asymptomatic atrial septal defect: a case report and review of the literature. J Med Case Rep 2011;5:142–5. [23] Kizer JR, Devereux RB. Patent foramen ovale in young adults with unexplained stroke. N Engl J Med 2005;353:2361–72. [24] Benneker LM, Krebs J, Boner V, et al. Cardiovascular changes after PMMA vertebroplasty in sheep: the effect of bone marrow removal using pulsed jet-lavage. Eur Spine J 2010;19:1913–20. [25] Cavallazzi R, Cavallazzi AC. The effect of corticosteroids on the prevention of fat embolism syndrome after long bone fracture of the lower limbs: a systematic review and meta-analysis. J Bras Pneumol 2008;34:34–41. [26] Bederman SS, Bhandari M, McKee MD, Schemitsch EH. Do corticosteroids reduce the risk of fat embolisation syndrome in patients with long-bone fractures? Can J Surg 2009;52:386–93. [27] Krebs J, Ferguson SJ, Nuss K, et al. Sildenafil prevents cardiovascular changes after bone marrow fat embolization in sheep. Anesthesiology 2007;107:75–81.
Case Report
Fat embolism syndrome following percutaneous vertebroplasty: a case report Hasib Ahmadzai, MBBS (Hons I), BSc (Med) Hons Ia,b,*, Scott Campbell, MBBS (Hons)a,b, Constantine Archis, MBBS (Hons), FRACPa,b, William A. Clark, MBBS, MD, FRANZCRc a
Faculty of Medicine, University of New South Wales, Level 2, ASGM Building/Botany St, Sydney, New South Wales 2052, Australia b Department of Respiratory Medicine, St. George Hospital, Gray St, Kogarah, New South Wales 2217, Australia c Department of Radiology, St. George Private Hospital, 1 South St, Department of Radiology, Kogarah, New South Wales 2217, Australia Received 18 April 2013; revised 25 August 2013; accepted 19 September 2013
Abstract
BACKGROUND CONTEXT: Vertebroplasty is commonly performed for management of pain associated with vertebral compression fractures. There have been two previous reports of fatal fat embolism following vertebroplasty. Here we describe a case of fat embolism syndrome following this procedure, and also provide fluoroscopic video evidence consistent with this occurrence. PURPOSE: The purpose of this study was to review the literature and report a case of fat embolism syndrome in a patient who underwent percutaneous vertebroplasty for compression fracture. STUDY DESIGN/SETTING: The study design for this manuscript was of a clinical case report. METHODS: A 68-year-old woman who developed sudden back pain with minimal trauma was found to have a T6 vertebral compression fracture on radiographs and bone scans. Percutaneous vertebroplasty of T5 and T6 was performed. RESULTS: Fluoroscopic imaging during the procedure demonstrated compression and rarefaction of the fractured vertebra associated with changes in intrathoracic pressure. Immediately after the procedure, the patient’s back pain resolved and she was discharged home. Two days later, she developed increasing respiratory distress, confusion, and chest pain. A petechial rash on her upper arms also appeared. No evidence of bone cement leakage or pulmonary filling defects were seen on computed tomography-pulmonary angiography. Brain magnetic resonance imaging demonstrated hyperintensities in the periventricular and subcortical white matter on T2/fluid-attenuated inversion recovery sequences. A diagnosis of fat embolism syndrome was made, and the patient recovered with conservative management. CONCLUSIONS: Percutaneous vertebroplasty is a relatively safe and simple procedure, reducing pain and improving functional limitations in patients with vertebral fractures. This case demonstrates an uncommon yet serious complication of fat embolism syndrome. Clinicians must be aware of this complication when explaining the procedure to patients and provide prompt supportive care when it does occur. Ó 2014 Elsevier Inc. All rights reserved.
Keywords:
Percutaneous vertebroplasty; Fat embolism; Vertebral fracture; Polymethylmethacrylate
Introduction Percutaneous vertebroplasty is a relatively successful interventional radiological procedure introduced in 1984 [1]. It involves injection of acrylic bone cement (usually polymethylmethacrylate [PMMA]) into a vertebral body, FDA device/drug status: Not applicable. Author disclosures: HA: Nothing to disclose. SC: Nothing to disclose. CA: Nothing to disclose. WAC: Nothing to disclose. * Corresponding author. Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia. Tel.: 61-4-394-784-30. E-mail address: [email protected] (H. Ahmadzai) 1529-9430/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.spinee.2013.09.021
providing pain relief and bone stabilization. It is used commonly to treat vertebral osteoporotic fractures, osteolytic lesions from vertebral metastases, aggressive hemangioma, and multiple myeloma [2,3]. Complications occur infrequently but include local bleeding, infection, cement leakage into the spinal canal, paravertebral tissues, and perivertebral venous system, leading to cord or nerve root compression as well as pulmonary embolism from PMMA or bone marrow contents [4]. This report highlights a case of fat embolism syndrome following percutaneous vertebroplasty for an osteoporotic fracture in a woman who had been treated with prednisone for systemic lupus erythematosus
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H. Ahmadzai et al. / The Spine Journal 14 (2014) e1–e5
(SLE). It also displays dynamic fluoroscopic evidence showing the role of vertebral compression fractures in causing fat embolism.
Case report A 68-year-old obese woman suffering from a 2-week history of severe thoracic back pain after an osteoporotic compression fracture of the T6 vertebra secondary to steroid use was admitted for outpatient percutaneous vertebroplasty. Her background medical history included cerebral vasculitis related to SLE, for which she was taking prednisone (10 mg/day), mycophenolate, and clopidogrel. Brain magnetic resonance imaging (MRI) performed 1 year previously did not identify active vasculitis or any other abnormalities. She also had hypertension, hypercholesterolemia, and also took propranolol, fosinopril, atorvastatin, Caltrate, and cholecalciferol. The vertebroplasty was performed under local anesthetic. The T5- and T6-level procedures were accessed using a 13-gauge trocar placed via a left transpedicular approach. Fluoroscopic imaging at the time revealed respirationinduced compression and rarefaction movement of the fractured vertebra (Supplementary Video). The patient was noted to be dyspneic before the procedure, although denied underlying respiratory disease. Polymethylmethacrylate was injected into each vertebral body, using 7 mL at T6 and 5 mL at T5 with adequate filling achieved (Fig. 1). The patient remained stable throughout the procedure. She was given ceftriaxone for infection prophylaxis, and because she had no additional respiratory symptoms and was otherwise well, she was subsequently discharged. Two days after the procedure she presented to the emergency department with progressive confusion, rigors, and chest pain on deep inspiration. She had also become increasingly short of breath 1 day after the procedure but denied headache or visual changes. On examination she appeared centrally cyanosed and was disorientated. Her oxygen saturation was 84% on room air; respiratory rate, 28 breaths/minute; heart rate, 125 beats/minute; blood pressure, 120/80 mmHg; and temperature, 38.2 C. The rest of the examination and chest radiograph were unremarkable. Electrocardiography showed sinus tachycardia but no ischemic changes. Arterial blood gases indicated hypoxemia, with arterial oxygen pressure of 60.1 mmHg. Full blood count, urea, electrolytes, creatinine, and liver function tests were normal, although she had a C-reactive protein value of 107 mg/L (normal, !3 mg/L) and a mildly elevated D-dimer level of 0.8 mg/mL (normal, !0.5 mg/mL). Computed tomography-pulmonary angiogram did not identify any filling defects within the pulmonary arteries and there was no evidence of paravertebral or pulmonary cement leakage (Fig. 2). Brain MRI was performed the following day, which identified nodular T2/fluid-attenuated inversion recovery hyperintensities in the periventricular and
Fig. 1. Lateral fluoroscopic view of T5 and T6 vertebrae after cement injection. Refer to online supplementary data for a video of the procedure.
subcortical white matter bilaterally, with no acute areas of infarct observed in the corresponding magnetic resonance diffusion-weighted images (Fig. 3). This had the appearance of longstanding possible microvascular ischemia or cerebral vasculitis, although MRI performed 12 months previously showed no such changes. No follow-up MRI had been performed. Three days after the procedure, a bilateral dermal petechial rash on the extensor surface of the patient’s forearms and lower arms appeared. Taken together with the other clinical features, a diagnosis of fat embolism syndrome (FES) was made. The patient was initiated on 50 mg prednisone and given high-flow oxygen on admission, and her symptoms improved. She was kept in the hospital for observation, with resolution of all symptoms within 1 week. She remained well at the clinical follow-up.
Discussion The first clinical diagnosis of FES was made in a patient with a fractured femur in 1873. The widely accepted guidelines for the clinical diagnosis of FES were proposed by Gurd and Wilson [5] (Table); however, the classic triad of acute respiratory distress, altered mental status, and
H. Ahmadzai et al. / The Spine Journal 14 (2014) e1–e5
e3
Fig. 2. (Left, Middle) Computed tomographic pulmonary angiogram indicating no filling defects from a pulmonary embolism. (Right) Computed tomographic findings 2 days after vertebroplasty.
petechial rash is seen in only one-third of cases [6]. Fat embolism occurs most commonly after orthopedic trauma, although it can also occur in the setting of many medical conditions and as a surgical complication [7]. Patients undergoing vertebroplasty on multiple levels during the 1 session appear to be at greater risk [8], with two fatalities after this procedure reported in the literature [9–11]. Interestingly, there have also been two cases of patients who died of fat embolism after isolated vertebral compression fracture in whom no surgical interventions were performed [12,13]. Two theories exist regarding the development of clinical features in FES. The first postulates that large fat droplets released into the systemic circulation following raised intravertebral pressure obstruct end capillary beds mechanically. Hypoxemia and tachycardia are seen in more than 90% of cases [14] reflecting this obstruction within the pulmonary circulation [9,15,16]. Changes in cardiorespiratory parameters have been demonstrated in studies immediately after cement injection in sheep vertebroplasty, with fat
emboli demonstrated histologically [15–19]. The second theory hypothesis that released fat particles trigger a localized inflammatory reaction. This is evidenced by delayed onset of clinical features and development of nontraumatic FES [7]. The delayed clinical and radiological appearance of FES closely resembles acute respiratory distress syndrome [20], with vasoactive mediator release and fatty acid precipitation in response to trauma and inflammatory conditions [10]. Given our patient’s history of SLE and vasculitis, an inflammatory predisposition may explain why the syndrome develops in a small percentage of cases despite evidence of release of fat emboli following vertebroplasty. No studies have investigated this association, although atraumatic fat embolism has been described in the setting of SLE. In SLE immune complex deposition, coagulation abnormalities and lipid mobilization may also be important for FES development [21]. The T2/fluid-attenuated inversion recovery brain MRI hyperintensities were most likely the result of cerebral
Fig. 3. Axial magnetic resonance imaging brain T2/fluid-attenuated inversion recovery sequence (Left) indicating hyperintensities (arrows) in the paraventricular and subcortical white matter that were not apparent on the corresponding diffusion-weighted imaging sequence (Right).
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H. Ahmadzai et al. / The Spine Journal 14 (2014) e1–e5
Table Gurd and Wilson criteria for the diagnosis of fat embolism syndrome Major criteria
Minor criteria
Petechiae in a vest distribution and on arms Hypoxemia with PaO2 !60 mmHg, FiO2 #40% Central nervous system depression disproportionate to hypoxemia Pulmonary edema
Tachycardia, heart rate O110 beats/minute Pyrexia (temperature, O38.5 C) Emboli visible in retina Lipiduria Fat in sputum Unexplained drop in hematocrit or platelet count Increasing erythrocyte sedimentation rate
Conclusions We report a case of FES in a patient following percutaneous vertebroplasty, a procedure being used increasingly to treat painful osteoporotic fractures. Fat embolism syndrome exists as an uncommon but potentially fatal complication of this procedure. It is important to consider this complication after vertebral fractures and vertebroplasty, as with other orthopedic trauma and surgery. Treatment remains supportive. New studies suggest that augmenting the current technique by removing marrow and reducing intramedullary pressure during the procedure may reduce the risk of developing this complication, particularly in those with underlying disease.
FiO2, percentage inspired oxygen; PaO2, arterial oxygen pressure.
vasculitis; however, cerebral fat embolism does occur in some cases and may lead to focal neurologic deficits. This occurs as a result of fat emboli originating from the venous circulation and entering and obstructing a systemic artery. Paradoxical FES can occur as a result of a patent foramen ovale, atrial or ventricular septal defect, persistent truncus arteriosus, or arteriovenous malformations [22]. It is important to note that patent foramen ovale is present in up to ~27% of the general adult population and is usually asymptomatic [23], but is an important cause of paradoxical embolism, which may account for most cases of cerebral fat emboli. Transesophageal echocardiography had not been performed in our patient’s case to confirm this. The mental state changes observed in this condition are, however, usually the result of hypoxia and not necessarily cerebral fat emboli. A major role of vertebroplasty has been the fixation of painful osteoporotic vertebral fractures. Osteoporotic vertebrae contain a greater proportion of intramedullary fat, leading to extravasation of more marrow content into the pulmonary and cerebral circulation when fractured [15]. Augmenting vertebroplasty, such as with vent-hole drilling to reduce intramedullary pressure and pulsed-jet lavage to remove marrow content before cement injection, has been suggested in recent sheep studies as a way to minimize this [19,24]. This allowed for greater PMMA injection without increasing intravascular fat emboli on histopathological examination of the lungs [24]. This may be investigated through clinical trials, with a potential role to reduce the risk of FES in patients with underlying cardiorespiratory or inflammatory conditions. Supportive care remains the basis of treatment for FES, with early recognition and aggressive hemodynamic and ventilatory support [7]. The role of corticosteroids remains unclear, with two recent systematic reviews suggesting some prophylactic benefit, although no dosing threshold was given [25,26]. Nevertheless, the use of high-flow oxygen and increased prednisone dose probably helped our patient recover from fat embolism. The efficacy of other therapies such as albumin infusion and pulmonary vasodilators has yet to be proved [27].
Appendix Supplementary material Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.spinee.2013.09.021. References [1] Galibert P, Deramond H, Rosat P, Le Gars D. Preliminary report on the percutaneous vertebroplasty with acrylic cement as a treatment of vertebral hemangioma. Neurochirurgie 1987;33:166–8. [2] Diamond TH, Bryant C, Browne L, Clark WA. Clinical outcomes after acute osteoporotic vertebral fractures: a 2-year non-randomised trial comparing percutaneous vertebroplasty with conservative therapy. Med J Aust 2006;184:113–7. [3] Diamond TH, Hartwell T, Clarke W, Manoharan A. Percutaneous vertebroplasty for acute vertebral body fracture and deformity in multiple myeloma: a short report. Br J Haematol 2004; 124:485–7. [4] Laredo JD, Hamze B. Complications of percutaneous vertebroplasty and their prevention. Skeletal Radiol 2004;33:493–505. [5] Gurd AR, Wilson RI. The fat embolism syndrome. J Bone Joint Surg Br 1974;56B:408–16. [6] Talbot M, Schemitsch EH. Fat embolism syndrome: history, definition, epidemiology. Injury 2006;37(4 Suppl):S3–7. [7] Glazer JL, Onion DK. Fat embolism syndrome in a surgical patient. J Am Board Fam Pract 2001;14:310–3. [8] Childers JC Jr. Cardiovascular collapse and death during vertebroplasty. Radiology 2003;228:902. [9] Chen HL, Wong CS, Ho ST, et al. A lethal pulmonary embolism during percutaneous vertebroplasty. Anesth Analg 2002;95: 1060–2. [10] Syed MI, Jan S, Patel NA, et al. Fatal fat embolism after vertebroplasty: identification of the high-risk patient. AJNR Am J Neuroradiol 2006;27:343–5. [11] Temple JD, Ludwig SC, Ross WK, et al. Catastrophic fat embolism following augmentation of pedicle screws with bone cement: a case report. J Bone Joint Surg Am 2002;84-A:639–42. [12] Lastra RR, Saldanha V, Balasubramanian M, Handal J. Fatal fat embolism in isolated vertebral compression fracture. Eur Spine J 2010;19(2 Suppl):S200–2. [13] Lewis D, Jones R, Carpenter C, James S. Fatal fat embolism following an isolated vertebral fracture. Acta Orthop Belg 2007;73: 137–9. [14] Bulger EM, Smith DG, Maier RV, Jurkovich GJ. Fat embolism syndrome: a 10-year review. Arch Surg 1997;132:435–9.
H. Ahmadzai et al. / The Spine Journal 14 (2014) e1–e5 [15] Aebli N, Krebs J, Davis G, et al. Fat embolism and acute hypotension during vertebroplasty: an experimental study in sheep. Spine 2002;27:460–6. [16] Aebli N, Krebs J, Schwenke D, et al. Pressurization of vertebral bodies during vertebroplasty causes cardiovascular complications: an experimental study in sheep. Spine 2003;28:1513–20. [17] Krebs J, Ferguson SJ, Hoerstrup SP, et al. Influence of bone marrow fat embolism on coagulation activation in an ovine model of vertebroplasty. J Bone Joint Surg Am 2008;90:349–56. [18] Aebli N, Schwenke D, Davis G, et al. Polymethylmethacrylate causes prolonged pulmonary hypertension during fat embolism. Acta Orthop 2005;76:904–11. [19] Aebli N, Krebs J, Schwenke D, et al. Cardiovascular changes during multiple vertebroplasty with and without vent-hole: an experimental study in sheep. Spine 2003;28:1504–12. [20] Porpodis K, Karanikas M, Zarogoulidis P, et al. Fat embolism due to bilateral femoral fracture: a case report. Int J Gen Med 2012;5:59–63. [21] Katz DA, Ben-Ezra J, Factor SM, et al. Fatal pulmonary and cerebral fat embolism in systemic lupus erythematosus. JAMA 1983;250:2666–9.
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[22] Mueller F, Pfeifer C, Kinner B, et al. Post-traumatic fulminant paradoxical fat embolism syndrome in conjunction with asymptomatic atrial septal defect: a case report and review of the literature. J Med Case Rep 2011;5:142–5. [23] Kizer JR, Devereux RB. Patent foramen ovale in young adults with unexplained stroke. N Engl J Med 2005;353:2361–72. [24] Benneker LM, Krebs J, Boner V, et al. Cardiovascular changes after PMMA vertebroplasty in sheep: the effect of bone marrow removal using pulsed jet-lavage. Eur Spine J 2010;19:1913–20. [25] Cavallazzi R, Cavallazzi AC. The effect of corticosteroids on the prevention of fat embolism syndrome after long bone fracture of the lower limbs: a systematic review and meta-analysis. J Bras Pneumol 2008;34:34–41. [26] Bederman SS, Bhandari M, McKee MD, Schemitsch EH. Do corticosteroids reduce the risk of fat embolisation syndrome in patients with long-bone fractures? Can J Surg 2009;52:386–93. [27] Krebs J, Ferguson SJ, Nuss K, et al. Sildenafil prevents cardiovascular changes after bone marrow fat embolization in sheep. Anesthesiology 2007;107:75–81.
