Continuing Education Activity
A hangman’s fracture is a bilateral fracture traversing the pars interarticularis of cervical vertebrae 2 (C2) with an associated traumatic subluxation of C2 on cervical vertebrae 3 (C3). It is the second most common fracture of the C2 vertebrae following a fracture of the odontoid process. In the acute setting, a rigid cervical collar should be immediately placed. The majority of Hangman’s fractures may be successfully treated with external orthosis alone. Vascular imaging should be performed in all C1 to C3 fractures. Management options vary depending on the specifics of the injury. This activity describes the presentation, evaluation, and management of hangman's fracture and highlights the interprofessional team's role in the care of affected patients.
- Explain the causes of a hangman's fracture.
- Describe the presentation of a patient with a hangman's fracture.
- Summarize the treatment options available for hangman's fractures.
- Review interprofessional team strategies for enhancing coordination and communication to improve the management of hangman's fractures and optimize patient outcomes.
A hangman’s fracture is better described as bilateral fracture traversing the pars interarticularis of C2 with an associated traumatic subluxation of C2 on C3. It is the second most common fracture of the C2 vertebrae following a fracture of the odontoid process and is almost always stable without surgical intervention. Steele’s rule of thirds states that the cross-sectional area at the level of the atlas may be divided into three equally represented parts: the dens, space, and the spinal cord. This increased area for the spinal cord at this level allows for the relative lack of neurologic injury associated with a hangman’s fracture.
Schneider et al. coined the term hangman’s fracture in 1965. Despite the term implying a hyperextension and distraction injury, such as in the case of a judicial hanging, the more common mechanism of action is hyperextension and axial loading. These injuries are most commonly seen in motor vehicle accidents, diving injuries, or contact sports.
Fractures of the cervical spine are present in 1% to 3% of all trauma cases, of which 9% to 18% are of the C2 vertebrae. The incidence of C2 fractures has doubled from 3 per 100,000 to 6 per 100,000 from 1997 to 2014 in data reported from the Swedish National Patient Registry. Fractures of the odontoid process are much more common, representing 35% to 78% of all C2 fractures in the general population and as much as 89% of patients older than 70 years old. Meanwhile, hangman’s fractures represent 11% to 25% of all C2 vertebrae fractures.
It is vitally important to keep in mind the unique anatomy of the atlas-axis complex when treating their associated injuries. Unlike the subaxial cervical spine, the C1 to C2 complex does not contain an intervertebral disc; there are unique ligaments that allow for support of the cranium and provide the majority of cervical rotation. There is also a close relationship of the transverse foramen, which carries the vertebral artery through the cervical spine, with the C2 pedicle/pars interarticularis, which may slightly weaken this area allowing for a fracture to occur.
Multiple grading systems for hangman’s fractures exist; however, the Levine and Edwards classifications are the most widely used.
Levine and Edwards Classification
Angulation in this system is measured as the angle between the inferior endplate of C2 and C3. Anterior subluxation of C2 on C3 greater than 3 mm serves as a marker for C2 to C3 intervertebral disc disruption. It is important to recognize that this grading system does not apply to the pediatric population.
- Type 1: Less than 3 mm subluxation of C2 on C3, due to axial loading, stable, rigid cervical collar treatment
- Type 2: Disruption of the C2 to C3 disc, posterior longitudinal ligament, greater than 4 mm subluxation, greater than 11 degrees angulation, less than 5 mm requires a reduction in axial traction and halo fixation for 6 to 12 weeks while those greater than 5 mm can require surgery
- Type 2a: Less displacement more angular deformity, flexion injury, unstable, not suitable for axial traction, treatment in halo
- Type 3: C2 to C3 facet capsule disrupted, anterior longitudinal ligament disruption, unstable, may have a deficit, surgical candidates
Francis Grading System
Two factors are taken into consideration for the Francis Grading system: angulation and displacement. Angulation is measured by the degree of anterior angulation off the posterior vertebral line drawn straight up from the C3 vertebral body. Displacement is measured by the amount of anterolisthesis, either greater than or less than 3.5 mm.
- Type 1: Less than 11 degrees of angulation and less than 3.5 mm of displacement
- Type 2: Greater than 11 degrees of angulation and less than 3.5 mm of displacement
- Type 3: Less than 11 degrees of angulation and greater than 3.5 mm displacement
- Type 4: Greater than 11 degrees of angulation and greater than 3.5 mm of displacement
- Type 5: Complete disc disruption
Typical versus Atypical Fractures
It is important to recognize that not all C2, hangman’s type fractures can be described using these classification systems. A typical hangman’s fracture allows for separation of the anterior elements from the posterior elements of the C2 vertebrae, therefore increase the available space for the spinal cord. However, in the case of an atypical hangman’s fracture, the posterior aspect of the C2 vertebral body, not the bilateral pars, is involved. This leads to a higher risk of neurologic injury as the space remaining for the spinal cord does not increase secondary to the fracture.
History and Physical
It is important to recognize that outside of the obvious motor vehicle collisions and high-impact falls, low-energy and blunt trauma, especially in the elderly population, can induce significant unstable injury. History should also entertain fracture risk factors such as osteoporosis, metastatic burden, or vitamin D deficiencies. Physical exam findings include pain with palpation in the posterior portion of the neck, radiculopathy, myelopathy, and possible posterior fossa findings secondary to vertebral artery injury. A strict neurologic exam including cranial nerves, sensory, motor, and rectal tone is mandatory.
Laboratory tests should be ordered as an adjunct in overall medical status. Normalized hemoglobin, hematocrit, PT/PTT, INR, and platelet counts will be needed for operative intervention.
Evaluation with X-rays will provide limited but important information. Care must be taken to ensure proper radiographic imaging creates a picture from the occiput to the C7 through T1 disc space. This is essential in reviewing cervical spine trauma. Lateral, anteroposterior (AP), and open-mouth odontoid views are necessary. Approximately 93% of cervical spine injuries are apparent with combined, lateral, AP, and odontoid view radiographs. X-rays are an excellent modality for determining alignment during the immediate injury, post-operative period, as well as long-term follow-up.
CT scan is the most important modality for determining fracture etiology and ruling out an injury regarding a C2 fracture. Even if plain films are negative and clinical suspicion is high, a CT scan is warranted. CT scan does not directly evaluate the spinal cord, soft tissue, or ligamentous construct. It is important to recognize the importance that complete imaging will require dedicated thin-cut CT reconstructions. Non-contrast CT scan is adequate for evaluation of the bony anatomy for fracture. This can be coupled with a CT angiogram (see below) for evaluation of the vascular anatomy.
Evaluation with MRI is important for analyzing the ligamentous construct, disc space, spinal cord, nerve roots, and other soft tissue injuries. MRI is also useful for determining the acute nature of the fracture when this is otherwise unknown. This is done via non-contrasted imaging. T2 signal hyperintensities and STIR changes within the dens, ligaments, or soft tissue can illustrate an acute component. MRI is less dangerous than flexion-extension cervical injury. Furthermore, MRI evaluation is mandatory in evaluating the transverse ligament for the surgical decision matrix of non-displaced type II odontoid fractures. An intact transverse ligament is needed for the anterior placement of an odontoid screw.
Vascular imaging may be indicated. The vertebral artery’s second segment (V2) runs through the transverse foramen of C2 to C6, while V3 runs extradurally, exiting the C2 foramen across the sulcus arteriosus. This can place it at risk for injury. Indeed, in one series, 15% of patients with C1 to C2 fractures had a vertebral artery injury. Of which, type-III odontoid fractures posed the greatest risk. It is important to note that an untreated vertebral artery injury has a 24% stroke rate. CT angiography can be coupled to CT imaging upon fracture evaluation with consideration of kidney function. Level-III evidence suggests that patients with C1 to C3 fractures can be screened with multi-slice multi-detector CT angiography. At this time, MR angiography cannot be listed as the sole imaging modality for the evaluation of vertebral artery injury. The first-line investigation with percutaneous angiography is overly aggressive.
Treatment / Management
Treatment options include conservative management, cervical orthosis, halo-vest orthosis, and surgical procedures.
A rigid cervical collar represents the immediate first treatment. Nonunion may occur as frequently as 50% in odontoid fractures, but nonunion is rare in hangman’s fractures, with approximately 90% healing with immobilization alone. Level III evidence shows that a hangman’s fracture may be initially managed with immobilization with a halo-vest or collar alone. This produces a reduction rate of 97% to 100% and a fusion rate of 93% to 100%. External orthosis should be maintained for 8 to 14 weeks. It is important to remember that halo-vest orthosis is not very well tolerated in the elderly population, and therefore collar is recommended as first-line management.
Surgical fixation may be considered in the following scenarios:
- Severe angulation of C2 on C3 (Francis II and IV, Levine II)
- Disruption of the C2 to C3 disc space (Francis V, Levine II)
- Anterior displacement of C2 greater than 50% on C3
- Inability to establish or maintain alignment with external immobilization
- Nonunion after use of external immobilization
Internal fixation can be achieved via anterior fixation or by a variety of posterior constructs.
C2 to C3 anterior cervical discectomy and fusion may be used with anterior plating to stabilize the C2 to C3 vertebral bodies. The main benefit of the anterior approach is preserving the C1 motion, which drastically decreases the morbidity compared to posterior fixation.
- C1 to C2 transarticular screws
- C1 lateral mass and C2 pedicle screws
- C1 lateral mass and C2 pars interarticularis screws
- C1 to C2 wiring (also as an adjunct technique)
- Extension to C3 lateral mass if there is a disruption of the C2 to C3 intervertebral disc or facet joint capsules
Posterior fixation technique selection requires significant review by a neurosurgeon or orthopedic spine surgeon. It considers a variety of factors, including surgeon experience, fracture location, vertebral artery location, biomechanical suitability, and anatomical variations. Vascular imaging is mandatory to illustrate the location of the vertebral artery in the V2 and V3 segments. The patient’s overall functional status, medical optimization, and bone health must be evaluated in the operative decision-making.
Differential diagnoses include pseudosubluxation (generally C2 on C3) and the Mach effect.
Successful repair of the fractured bone(s) can lead to excellent recoveries with a good long-term prognosis. Some cases require fusion of the C2 and C3 vertebrae. Researchers studied fusion surgery performed via the posterior approach; this method demonstrated excellent results in 3-part fractures of the axis.
In another study of over 30 people with a hangman’s fracture, researchers found that 85 percent of patients with a hangman's fracture experienced a full recovery within a year.
These upper cervical fractures can be very unstable. Without treatment, the bones can shift, resulting in an increased deformity that can lead to serious damage to the spinal cord. With spinal cord damage, symptoms can include pain, sensory loss, muscle weakness or paralysis, or even death.
Deterrence and Patient Education
Patients need to understand that most cases will not require surgery. They may need to wear a neck collar to limit movement to promote healing and prevent further injury. More commonly, they will require halo immobilization.
Less commonly, the patient will require surgery. All aspects of the procedure need to be explained to the patient, and they should receive reassurance regarding the high degree of successful recovery following surgery, as cited above. They should also be given realistic expectations regarding recovery time, lasting as long as a year.
Pearls and Other Issues
- A rigid cervical collar should be immediately placed in the emergency room setting.
- The majority of Hangman’s fractures may be successfully treated with external orthosis alone.
- Vascular imaging should be performed in all C1 to C3 fractures.
Enhancing Healthcare Team Outcomes
Fractures of the spine are best managed by an interprofessional team that includes clinicians (including PAs and NPs), specialists (orthopedists, neurologists), orthopedic and neurology nurses, and therapists. Physical therapy may play a role in rehabilitative recovery in both surgical and non-surgical cases. This interprofessional approach will result in improved patient outcomes. [Level 5]
Clinicians should be aware that imaging is critical for the diagnosis of hangman's fracture. CT scan is the most important modality for determining fracture etiology and ruling out an injury regarding a C2 fracture. Even if plain films are negative and clinical suspicion is high, a CT scan is warranted. CT scan does not directly evaluate the spinal cord, soft tissue, or ligamentous construct. It is important to recognize the importance that complete imaging will require dedicated thin-cut CT reconstructions. Non-contrast CT scan is adequate for evaluation of the bony anatomy for fracture. This can be coupled with a CT angiogram for evaluation of the vascular anatomy. A missed injury can prove fatal.
Most patients can be managed with external support, and with time full recovery is possible.