Traumatic Spondylolisthesis

The axis (C2) has a solid front part bearing its upward peg, and a bony ring behind through which the spinal cord passes. Connecting the front and back is a narrow bridge of bone on each side. In traumatic spondylolisthesis, these bridges fracture on both sides, effectively separating the front of the bone from the back. Because the two parts can then move independently, the front part (and the skull and atlas above it) may slip forward on the third neck bone (C3) below.

The usual mechanism today is a sudden forceful backward bending (hyperextension) of the neck combined with axial loading — for example striking the forehead in a road traffic collision or a fall. High-energy trauma is typical, though in older people with weaker bone, lower-energy injuries can be responsible. The classical association with hanging, from which the injury takes its name, is now of historical interest only.

These injuries are commonly described using a grading system based on how far the bone has slipped and how angled it is, and on whether the disc and ligaments below are disrupted. In broad terms, injuries range from a minimally displaced, stable fracture, through fractures with significant slippage and angulation, to the most severe injuries in which the C2–C3 joint is also dislocated. The grade strongly influences whether the injury can be treated in a brace or needs surgery.

The usual symptom is pain at the top of the neck, with stiffness and a reluctance to move the head. Because the spinal cord is often spared, many people have no arm or leg symptoms. However, any weakness, numbness, or difficulty with breathing or swallowing is important and is assessed carefully, as more severe, displaced injuries can affect the cord.

As with any significant neck injury, the neck should be kept still and the person assessed urgently after a high-energy accident. Warning signs that require immediate attention include weakness or numbness in the arms or legs, problems with balance, and any difficulty breathing or swallowing. Even when there are no such symptoms, the injury needs prompt, careful evaluation because it can be unstable.

A CT scan is the key test, clearly showing the fractures through the ring of the axis and the degree of slippage and angulation. Plain X-rays, including views taken with the neck carefully positioned, can show the forward slip. An MRI scan assesses the disc and ligaments below the fracture, which is important because their disruption affects stability and treatment. Together these define the grade of the injury.

Many hangman's fractures are relatively stable and can be treated without surgery. Minimally displaced injuries are often managed in a rigid collar or brace for a period of weeks while the bone heals. More displaced but still-reducible injuries may be realigned and then held in a rigid brace or, in selected cases, a halo (a frame fixed to the skull and a vest) until healing occurs. Regular imaging checks the alignment during treatment.

Surgery is considered for the more severe and unstable injuries — those with marked slippage or angulation, disruption of the disc and ligaments below, or an associated dislocation of the C2–C3 joint — and for fractures that fail to stay aligned in a brace. Operations aim to realign and stabilise the injured level, from the front, the back, or both. The choice of treatment is individual and takes account of the grade of injury, the person's age and their general health.

The outlook for hangman's fractures is generally good, and the majority heal, whether treated in a brace or with surgery, often with well-preserved neck function. More severe, displaced injuries and those with cord involvement are more complex, and their outlook reflects the specific injury and its treatment. Rehabilitation supports the return of movement and function once healing is under way.

Potential problems include failure of the fracture to heal in a good position, residual neck pain or stiffness, and the specific risks of a halo, a brace or surgery. Displaced injuries carry a risk of neurological problems. Careful follow-up imaging is used to confirm healing and alignment and to detect any complication early.

Myth: "A hangman's fracture is usually fatal or causes paralysis." Fact: The injuries seen today are almost always from road or fall trauma, and most do not damage the spinal cord.

Myth: "It always needs surgery." Fact: Many hangman's fractures are treated successfully in a collar, brace or halo; surgery is reserved for unstable or displaced injuries.

Myth: "All C2 fractures are the same." Fact: The hangman's fracture (through the ring) is different from an odontoid (peg) fracture; they are graded and treated differently.

This page is for general education and does not replace an individual assessment. Treatment depends on a person's specific symptoms, examination findings, imaging findings and overall health, and should always be discussed with a suitably qualified healthcare professional.

"Spondylolisthesis" means the slipping forward of one vertebra on the one below. When this happens because of an injury it is called traumatic spondylolisthesis, and its classic form occurs at the second bone of the neck, the axis (C2). Here a fracture passes through the bony ring on both sides, separating the front part of the bone (which carries the peg) from the back part, and allowing the front to slide forward. This injury is traditionally called the hangman's fracture because of its association with judicial hanging, but the injuries seen today are almost always caused by road traffic collisions and falls, and — reassuringly — most do not damage the spinal cord, because the fracture tends to open up the space around the cord rather than narrow it. This page explains the injury, how it is graded and how it is treated.

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• —Al-Mahfoudh R, Beagrie C, Woolley E, et al. Management of typical and atypical hangman's fractures. Global Spine J. 2016;6(3):248-256. doi:10.1055/s-0035-1563404
• —National Institute for Health and Care Excellence (NICE). Spinal injury: assessment and initial management. NICE guideline NG41. 2016. https://www.nice.org.uk/guidance/ng41
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• —Guideline note (place near references): The Congress of Neurological Surgeons / AANS "Guidelines for the Management of Acute Cervical Spine and Spinal Cord Injuries" (2013) and NICE NG41 were reviewed. No stand-alone AAOS clinical practice guideline specific to traumatic spondylolisthesis of the axis was identified at the time of writing.

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.