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A Pitfall in Neck Pain: Occult Odontoid Fracture
The Journal of Emergency Medicine, Vol. 38, No. 5, pp. 593–596, 2010 Copyright © 2010 Elsevier Inc. Printed in the USA. All rights reserved 0736-4679/$–see front matter
doi:10.1016/j.jemermed.2007.08.059
Clinical Communications: Adults
A PITFALL IN NECK PAIN: OCCULT ODONTOID FRACTURE Cheng-Ta Hsieh,
MD,*
Yung-Hsiao Chiang, MD, PHD,* Tai-Feng Chiu, and Cheng-Fu Chang, MD, PHD*
MD,†
Jui-Ming Sun,
MD,*
*Department of Neurological Surgery and †Department of Emergency Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China Reprint Address: Cheng-Fu Chang, MD, PHD, Department of Neurological Surgery, Tri-Service General Hospital, #325 Cheng-Kung Road, Section 2, Taipei 114, Taiwan, Republic of China
e Abstract—Type III odontoid fractures of the axis are the second most common injuries of the cervical spine. Most of these result from motor vehicle accidents and falls. Occult odontoid fractures without preceding trauma are rarely reported in the literature and may be difficult to diagnose. We report the case of a healthy patient who had no history of trauma, but sustained sudden pain in the neck and guarding during head movement after sleep. Initial radiographs of the cervical spine including open-mouth, anterior-posterior, and lateral views did not reveal any obvious fractures. Type III odontoid fracture was uneventfully diagnosed via high-quality three-dimensional reconstruction of computed tomography. The possible mechanism was hyperextension of the neck during the change from the supine to the sitting position. Type III odontoid fractures can occur in the absence of major trauma. The usefulness of computed tomography is emphasized and the literature is also reviewed. © 2010 Elsevier Inc.
fracture extends deep into the body of C2 at the base of the dens. Occult odontoid fracture without a traumatic event in healthy patients rarely has been reported in the literature and remains a challenge for emergency physicians (3). The purpose in presenting this case is to raise awareness among emergency physicians of occult odontoid fractures in the absence of trauma and to emphasize the usefulness of images from three-dimensional reconstructions of computed tomography (CT). CASE REPORT A 49-year-old man experienced sudden pain and soreness in his neck when he awoke from a midday nap. He reported no major traumatic event just before the onset of his symptoms or in the past. On arrival at the Emergency Department, he complained of severe neck pain and numbness in his left hand but no muscle weakness. His vital signs demonstrated a normal temperature of 36.9°C, respiratory rate 18 breaths/min, heart rate 87 beats/min, and blood pressure 149/78 mm Hg. On physical examination, he was alert and oriented but agitated, and resisted moving his neck due to severe pain. In addition, the patient also experienced hypoesthesia in the entire left hand. Motor strength in all four limbs, deep tendon reflexes, Hoffmann’s sign, and Babinski’s sign were normal. A series of laboratory tests revealed no remarkable findings. Radiographs of the cervical spine, includ-
e Keywords— cervical spine; occult; odontoid fracture
INTRODUCTION Odontoid fractures of the axis are not infrequent, and comprise a significant proportion of acute cervical spinal injuries (1). Type III fractures of the odontoid process of the axis, classified by Anderson and D’Alonzo, are the second most common injury of the odontoid process, most resulting from traumatic events (2). A type III
RECEIVED: 7 June 2006; FINAL ACCEPTED: 1 August 2007
SUBMISSION RECEIVED:
5 May 2007; 593
594
C.-T. Hsieh et al.
the cervical cord. A type III odontoid fracture was diagnosed. After explanation was given to the patient, conservative treatment with a rigid neck collar was recommended. The patient did well and his symptoms had resolved 1 month later.
DISCUSSION
Figure 1. (A) Radiograph of open-mouth view of cervical spine that did not reveal fracture of the axis. (B) Radiography of lateral view of cervical spine did not reveal the widening of atlantal-dense distance.
ing open-mouth, anterior-posterior, and lateral views, showed cervical spondylolysis with marginal osteophytes, normal curvature, and no obvious fractures (Figure 1). Due to the severity of his symptoms and signs, CT scan of the cervical spine was performed 1 h later. CT scan reconstructions revealed a fracture of the axis from the base of the odontoid process to the vertebral body without significant displacement of the fragment, and a bulging disc at C6/7 (Figure 2). Magnetic resonance imaging demonstrated increased signal on T2-weighted images over the fracture sites and high signal foci over
Fractures of the odontoid process of the second cervical vertebra are not an uncommon injury, and account for 7–20% of all fractures of the cervical spine (4 –7). According to the nomenclature by Anderson and D’Alonzo, three types of odontoid fractures are classified (2). Type I fractures are oblique fractures through the upper portion of the odontoid process. Type II fractures cross the base of the odontoid process at the junction with the axis body. Type III fractures are fractures through the cancellous portion of the body of axis. Type III fractures of the odontoid process comprise 18 –23% of odontoid fractures (6 – 8). The most common causes of injuries are motor-vehicle accidents (65–71%), followed by falls (14 –15%) and diving injuries (4 – 6%) (7,8). Unlike the elder population, in whom odontoid fractures are caused by low-energy trauma like falls, in the younger population they are frequently caused by high-energy injuries (9). However, except for pathological or osteoporotic causes, odontoid fractures in patients without any traumatic events, such as in our case, are rarely described in the literature. Fractures of the odontoid process are mostly induced from non-physiological force, producing flexion, extension, or rotation of the upper cervical spine, but the exact mechanism is controversial. In the examination of postmortem radiographs of 312 victims of fatal motor vehicle accidents, Alker et al. hypothesized that odontoid fractures were probably due to hyperextension because of the posterior displacement of the fracture fragments (10). In a laboratory biomechanical study using cadaver preparations, Mouradian et al. demonstrated that hyperextension was found to be the main mechanism of injury for type III odontoid fractures (11). However, a threedimensional, non-linear finite element model of the occipito-atlantoaxial complex, reported by Puttlitz et al., revealed hyperextension coupled with lateral shear or compression leads to Type I fracture, axial rotation and lateral shear can produce type II fracture, and the causal mechanisms for Type III fractures are unpredictable (12). In our case, the posture with hyperextension of the neck was highly suggestive as the causal mechanisms when the patient moved from the supine to the sitting position. Clinical presentations in patients with axis fracture vary depending on the impact of force and the pathophysiological mechanism, and range from symptoms of
Occult Odontoid Fracture
595
Figure 2. (A) Axial view of computed tomography scan of C1–2 revealed one fracture line (white arrow) over left body of axis bone. (B) Sagittal view of computed tomography scan in the cervical spine revealed the fracture line (white arrow) over the body of axis bone. (C) Three-dimensional reconstruction of computed tomography scan revealed one fracture line (white arrow) from the left base of den to the left body of axis.
pain in the neck to paralysis, even to death (8). In a comprehensive review of axis fractures in 107 cases by Hadley et al., 91 patients (85%) presented with symptoms of pain, 11 (10%) had paresthesias, 8 (7%) complained of specific motor weakness, and 14 (13%) had some paralysis at the time of presentation (6). Mortality
rate at the scene of an accident has been estimated to be 25– 40% in patients with acute axis fracture (7). Radiographs are routinely used as a screening tool for detecting cervical spine injuries in trauma patients. Due to their low sensitivity for minor changes, radiographs could not absolutely rule out occult cervical fractures,
596
C.-T. Hsieh et al.
especially in patients without traumatic events. In a review of 68 patients with occult cervical spine fractures, Lin et al. reported 26 patients (38%) who showed occult fractures on initial radiographs after correlating with computed tomography (13). Also, odontoid, facet, and lower cervical spine fractures were most commonly occult on first radiographs. Edwards et al. also reported fractures of the neck that were not detected by cervical spine radiographs, but were diagnosed by clinical investigation and CT scan in 23.7% (9 of 38) (14). Repeat radiographs, particularly flexion and extension views, were suggested to discover occult cervical spine injuries if initial radiographs were negative and neurological deficits persisted (13). With the advance of radiological techniques, CT scan of the cervical spine, especially high-quality three-dimensional reconstruction images, is more sensitive (99% vs. 94%, respectively), more specific (93% vs. 78 – 89%, respectively), and faster than conventional radiographs for evaluating cervical spine injuries (15). In our opinion, high-quality CT reconstructions can improve the diagnosis of cervical spine fracture, and help relate neurological findings with conventional radiographs.
CONCLUSIONS In summary, odontoid fracture should be considered in the differential diagnosis of a non-traumatic patient who develops sudden pain in the neck. Detailed history, accurate physical examination, and advanced radiological techniques, such as high-quality CT with reconstruction, are important for detection of occult cervical spine fractures in the Emergency Department.
REFERENCES 1. Harrop JS, Vaccaro A, Przybylski GJ. Acute respiratory compromise associated with flexed cervical traction after C2 fractures. Spine 2001;26:E50 – 4. 2. Anderson LD, D’Alonzo RT. Fractures of the odontoid process of the axis. J Bone Joint Surg Am 1974;56:1663–74. 3. Lewandrowski KU, Park PP, Baron JM, Curtin SL. Atraumatic odontoid fractures in patients with rheumatoid arthritis. Spine J 2006;6:529 –33. 4. Pepin JW, Bourne RB, Hawkins RJ. Odontoid fractures, with special reference to the elderly patient. Clin Orthop Relat Res 1985;178 – 83. 5. Kirkpatrick JS, Sheils T, Theiss SM. Type-III dens fracture with distraction: an unstable injury. A report of three cases. J Bone Joint Surg Am 2004;86-A:2514 – 8. 6. Hadley MN, Browner C, Sonntag VK. Axis fractures: a comprehensive review of management and treatment in 107 cases. Neurosurgery 1985;17:281–90. 7. Hadley MN, Dickman CA, Browner CM, Sonntag VK. Acute axis fractures: a review of 229 cases. J Neurosurg 1989;71:642–7. 8. Greene KA, Dickman CA, Marciano FF, Drabier JB, Hadley MN, Sonntag VK. Acute axis fractures. Analysis of management and outcome in 340 consecutive cases. Spine 1997;22:1843–52. 9. Lakshmanan P, Jones A, Howes J, Lyons K. CT evaluation of the pattern of odontoid fractures in the elderly—relationship to upper cervical spine osteoarthritis. Eur Spine J 2005;14:78 – 83. 10. Alker GJ Jr, Oh YS, Leslie EV. High cervical spine and craniocervical junction injuries in fatal traffic accidents: a radiological study. Orthop Clin North Am 1978;9:1003–10. 11. Mouradian WH, Fietti VG Jr, Cochran GV, Fielding JW, Young J. Fractures of the odontoid: a laboratory and clinical study of mechanisms. Orthop Clin North Am 1978;9:985–1001. 12. Puttlitz CM, Goel VK, Clark CR, Traynelis VC. Pathomechanisms of failures of the odontoid. Spine 2000;25:2868 –76. 13. Lin JT, Lee JL, Lee ST. Evaluation of occult cervical spine fractures on radiographs and CT. Emerg Radiol 2003;10:128 –34. 14. Edwards MJ, Frankema SP, Kruit MC, Bode PJ, Breslau PJ, van Vugt AB. Routine cervical spine radiography for trauma victims: does everybody need it? J Trauma 2001;50:529 –34. 15. Blackmore CC, Mann FA, Wilson AJ. Helical CT in the primary trauma evaluation of the cervical spine: an evidence-based approach. Skeletal Radiol 2000;29:632–9.
doi:10.1016/j.jemermed.2007.08.059
Clinical Communications: Adults
A PITFALL IN NECK PAIN: OCCULT ODONTOID FRACTURE Cheng-Ta Hsieh,
MD,*
Yung-Hsiao Chiang, MD, PHD,* Tai-Feng Chiu, and Cheng-Fu Chang, MD, PHD*
MD,†
Jui-Ming Sun,
MD,*
*Department of Neurological Surgery and †Department of Emergency Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China Reprint Address: Cheng-Fu Chang, MD, PHD, Department of Neurological Surgery, Tri-Service General Hospital, #325 Cheng-Kung Road, Section 2, Taipei 114, Taiwan, Republic of China
e Abstract—Type III odontoid fractures of the axis are the second most common injuries of the cervical spine. Most of these result from motor vehicle accidents and falls. Occult odontoid fractures without preceding trauma are rarely reported in the literature and may be difficult to diagnose. We report the case of a healthy patient who had no history of trauma, but sustained sudden pain in the neck and guarding during head movement after sleep. Initial radiographs of the cervical spine including open-mouth, anterior-posterior, and lateral views did not reveal any obvious fractures. Type III odontoid fracture was uneventfully diagnosed via high-quality three-dimensional reconstruction of computed tomography. The possible mechanism was hyperextension of the neck during the change from the supine to the sitting position. Type III odontoid fractures can occur in the absence of major trauma. The usefulness of computed tomography is emphasized and the literature is also reviewed. © 2010 Elsevier Inc.
fracture extends deep into the body of C2 at the base of the dens. Occult odontoid fracture without a traumatic event in healthy patients rarely has been reported in the literature and remains a challenge for emergency physicians (3). The purpose in presenting this case is to raise awareness among emergency physicians of occult odontoid fractures in the absence of trauma and to emphasize the usefulness of images from three-dimensional reconstructions of computed tomography (CT). CASE REPORT A 49-year-old man experienced sudden pain and soreness in his neck when he awoke from a midday nap. He reported no major traumatic event just before the onset of his symptoms or in the past. On arrival at the Emergency Department, he complained of severe neck pain and numbness in his left hand but no muscle weakness. His vital signs demonstrated a normal temperature of 36.9°C, respiratory rate 18 breaths/min, heart rate 87 beats/min, and blood pressure 149/78 mm Hg. On physical examination, he was alert and oriented but agitated, and resisted moving his neck due to severe pain. In addition, the patient also experienced hypoesthesia in the entire left hand. Motor strength in all four limbs, deep tendon reflexes, Hoffmann’s sign, and Babinski’s sign were normal. A series of laboratory tests revealed no remarkable findings. Radiographs of the cervical spine, includ-
e Keywords— cervical spine; occult; odontoid fracture
INTRODUCTION Odontoid fractures of the axis are not infrequent, and comprise a significant proportion of acute cervical spinal injuries (1). Type III fractures of the odontoid process of the axis, classified by Anderson and D’Alonzo, are the second most common injury of the odontoid process, most resulting from traumatic events (2). A type III
RECEIVED: 7 June 2006; FINAL ACCEPTED: 1 August 2007
SUBMISSION RECEIVED:
5 May 2007; 593
594
C.-T. Hsieh et al.
the cervical cord. A type III odontoid fracture was diagnosed. After explanation was given to the patient, conservative treatment with a rigid neck collar was recommended. The patient did well and his symptoms had resolved 1 month later.
DISCUSSION
Figure 1. (A) Radiograph of open-mouth view of cervical spine that did not reveal fracture of the axis. (B) Radiography of lateral view of cervical spine did not reveal the widening of atlantal-dense distance.
ing open-mouth, anterior-posterior, and lateral views, showed cervical spondylolysis with marginal osteophytes, normal curvature, and no obvious fractures (Figure 1). Due to the severity of his symptoms and signs, CT scan of the cervical spine was performed 1 h later. CT scan reconstructions revealed a fracture of the axis from the base of the odontoid process to the vertebral body without significant displacement of the fragment, and a bulging disc at C6/7 (Figure 2). Magnetic resonance imaging demonstrated increased signal on T2-weighted images over the fracture sites and high signal foci over
Fractures of the odontoid process of the second cervical vertebra are not an uncommon injury, and account for 7–20% of all fractures of the cervical spine (4 –7). According to the nomenclature by Anderson and D’Alonzo, three types of odontoid fractures are classified (2). Type I fractures are oblique fractures through the upper portion of the odontoid process. Type II fractures cross the base of the odontoid process at the junction with the axis body. Type III fractures are fractures through the cancellous portion of the body of axis. Type III fractures of the odontoid process comprise 18 –23% of odontoid fractures (6 – 8). The most common causes of injuries are motor-vehicle accidents (65–71%), followed by falls (14 –15%) and diving injuries (4 – 6%) (7,8). Unlike the elder population, in whom odontoid fractures are caused by low-energy trauma like falls, in the younger population they are frequently caused by high-energy injuries (9). However, except for pathological or osteoporotic causes, odontoid fractures in patients without any traumatic events, such as in our case, are rarely described in the literature. Fractures of the odontoid process are mostly induced from non-physiological force, producing flexion, extension, or rotation of the upper cervical spine, but the exact mechanism is controversial. In the examination of postmortem radiographs of 312 victims of fatal motor vehicle accidents, Alker et al. hypothesized that odontoid fractures were probably due to hyperextension because of the posterior displacement of the fracture fragments (10). In a laboratory biomechanical study using cadaver preparations, Mouradian et al. demonstrated that hyperextension was found to be the main mechanism of injury for type III odontoid fractures (11). However, a threedimensional, non-linear finite element model of the occipito-atlantoaxial complex, reported by Puttlitz et al., revealed hyperextension coupled with lateral shear or compression leads to Type I fracture, axial rotation and lateral shear can produce type II fracture, and the causal mechanisms for Type III fractures are unpredictable (12). In our case, the posture with hyperextension of the neck was highly suggestive as the causal mechanisms when the patient moved from the supine to the sitting position. Clinical presentations in patients with axis fracture vary depending on the impact of force and the pathophysiological mechanism, and range from symptoms of
Occult Odontoid Fracture
595
Figure 2. (A) Axial view of computed tomography scan of C1–2 revealed one fracture line (white arrow) over left body of axis bone. (B) Sagittal view of computed tomography scan in the cervical spine revealed the fracture line (white arrow) over the body of axis bone. (C) Three-dimensional reconstruction of computed tomography scan revealed one fracture line (white arrow) from the left base of den to the left body of axis.
pain in the neck to paralysis, even to death (8). In a comprehensive review of axis fractures in 107 cases by Hadley et al., 91 patients (85%) presented with symptoms of pain, 11 (10%) had paresthesias, 8 (7%) complained of specific motor weakness, and 14 (13%) had some paralysis at the time of presentation (6). Mortality
rate at the scene of an accident has been estimated to be 25– 40% in patients with acute axis fracture (7). Radiographs are routinely used as a screening tool for detecting cervical spine injuries in trauma patients. Due to their low sensitivity for minor changes, radiographs could not absolutely rule out occult cervical fractures,
596
C.-T. Hsieh et al.
especially in patients without traumatic events. In a review of 68 patients with occult cervical spine fractures, Lin et al. reported 26 patients (38%) who showed occult fractures on initial radiographs after correlating with computed tomography (13). Also, odontoid, facet, and lower cervical spine fractures were most commonly occult on first radiographs. Edwards et al. also reported fractures of the neck that were not detected by cervical spine radiographs, but were diagnosed by clinical investigation and CT scan in 23.7% (9 of 38) (14). Repeat radiographs, particularly flexion and extension views, were suggested to discover occult cervical spine injuries if initial radiographs were negative and neurological deficits persisted (13). With the advance of radiological techniques, CT scan of the cervical spine, especially high-quality three-dimensional reconstruction images, is more sensitive (99% vs. 94%, respectively), more specific (93% vs. 78 – 89%, respectively), and faster than conventional radiographs for evaluating cervical spine injuries (15). In our opinion, high-quality CT reconstructions can improve the diagnosis of cervical spine fracture, and help relate neurological findings with conventional radiographs.
CONCLUSIONS In summary, odontoid fracture should be considered in the differential diagnosis of a non-traumatic patient who develops sudden pain in the neck. Detailed history, accurate physical examination, and advanced radiological techniques, such as high-quality CT with reconstruction, are important for detection of occult cervical spine fractures in the Emergency Department.
REFERENCES 1. Harrop JS, Vaccaro A, Przybylski GJ. Acute respiratory compromise associated with flexed cervical traction after C2 fractures. Spine 2001;26:E50 – 4. 2. Anderson LD, D’Alonzo RT. Fractures of the odontoid process of the axis. J Bone Joint Surg Am 1974;56:1663–74. 3. Lewandrowski KU, Park PP, Baron JM, Curtin SL. Atraumatic odontoid fractures in patients with rheumatoid arthritis. Spine J 2006;6:529 –33. 4. Pepin JW, Bourne RB, Hawkins RJ. Odontoid fractures, with special reference to the elderly patient. Clin Orthop Relat Res 1985;178 – 83. 5. Kirkpatrick JS, Sheils T, Theiss SM. Type-III dens fracture with distraction: an unstable injury. A report of three cases. J Bone Joint Surg Am 2004;86-A:2514 – 8. 6. Hadley MN, Browner C, Sonntag VK. Axis fractures: a comprehensive review of management and treatment in 107 cases. Neurosurgery 1985;17:281–90. 7. Hadley MN, Dickman CA, Browner CM, Sonntag VK. Acute axis fractures: a review of 229 cases. J Neurosurg 1989;71:642–7. 8. Greene KA, Dickman CA, Marciano FF, Drabier JB, Hadley MN, Sonntag VK. Acute axis fractures. Analysis of management and outcome in 340 consecutive cases. Spine 1997;22:1843–52. 9. Lakshmanan P, Jones A, Howes J, Lyons K. CT evaluation of the pattern of odontoid fractures in the elderly—relationship to upper cervical spine osteoarthritis. Eur Spine J 2005;14:78 – 83. 10. Alker GJ Jr, Oh YS, Leslie EV. High cervical spine and craniocervical junction injuries in fatal traffic accidents: a radiological study. Orthop Clin North Am 1978;9:1003–10. 11. Mouradian WH, Fietti VG Jr, Cochran GV, Fielding JW, Young J. Fractures of the odontoid: a laboratory and clinical study of mechanisms. Orthop Clin North Am 1978;9:985–1001. 12. Puttlitz CM, Goel VK, Clark CR, Traynelis VC. Pathomechanisms of failures of the odontoid. Spine 2000;25:2868 –76. 13. Lin JT, Lee JL, Lee ST. Evaluation of occult cervical spine fractures on radiographs and CT. Emerg Radiol 2003;10:128 –34. 14. Edwards MJ, Frankema SP, Kruit MC, Bode PJ, Breslau PJ, van Vugt AB. Routine cervical spine radiography for trauma victims: does everybody need it? J Trauma 2001;50:529 –34. 15. Blackmore CC, Mann FA, Wilson AJ. Helical CT in the primary trauma evaluation of the cervical spine: an evidence-based approach. Skeletal Radiol 2000;29:632–9.