Traumatic Spondylolisthesis of Axis (Hangman's Fracture) - Spine

summary
- Traumatic Spondylolisthesis of Axis, also known as a Hangman's Fracture, is a traumatic fracture of the bilateral pars interarticularis of C2.
- Diagnosis is made with CT of the cervical spine.
- Treatment may be C-collar immobilization, halo immobilization, or surgical stabilization depending on displacement, angulation, and fracture stability.

Etiology
- Mechanism
  - hyperextension
    
    leads to fracture of pars
  - secondary flexion
    
    tears PLL and disc allowing subluxation
- Associated injuries
  - 30% have concomitant c-spine fx

Presentation
- Symptoms
  - neck pain
- Physical exam
  - patients are usually neurologically intact

Imaging
- Radiographs
  - flexion and extension radiographs show subluxation
- CT
  - study of choice to delineate fracture pattern
- MRA
  - consider if suspicious of a vascular injury to the vertebral artery

                        Classification 
                    
                        Levine and Edwards Classification
                    
                        (based on mechanism of injury)
                    
                        Mechanism
                    
                        Characteristics
                    
                        Treatment
                    
                        Type I
                    
                        Axial compression and hyperextension
                    
                        < 3mm horizontal displacement C2/3
                    
                         No angulation
                    
                         C2/3 disc remains intact
                    
                         Stable fx pattern
                    
                        Rigid collar x 4-6 weeks
                    
                        Type II
                    
                        Hyperextension and axial load followed by rebound flexion
                    
                        > 3mm of horizontal displacement
                    
                         Significant angulation
                    
                         Vertical fracture line
                    
                         C2/3 disc and PLL are disrupted
                    
                         Unstable fracture pattern
                    
                        If < 5 mm displacement, reduction with traction then halo immobilization x 6-12 weeks
                    
                         If > 5mm displacement,  displacement, surgery or prolonged traction
                    
                         Usually heal despite displacement (autofuse C2 on C3)
                    
                        Type IIA
                    
                        Flexion-distraction
                    
                        No horizontal displacement
                    
                         Horizontal fracture line
                    
                         Significant angulation
                    
                        Avoid traction in Type IIA.
                    
                         Reduction with gentle axial load + hyperextension, then compression halo immobilization for 6-12 weeks.
                    
                        Type III
                    
                        Flexion-distraction followed by hyperextension
                    
                        Type I fracture with associated bilateral C2-3 facet dislocation
                    
                         Rare injury pattern
                    
                        Surgical reduction of facet dislocation followed by stabilization required.

Treatment
- Nonoperative
  - rigid cervical collar x 4-6 weeks
    
    indications
    
    Type I fractures (< 3mm horizontal displacement)
  - closed reduction followed by halo immobilization for 8-12 weeks
    
    indications
    
    Type II with 3-5 mm displacement
    
    Type IIA
    
    reduction technique
    
    Type II use axial traction combined + extension
    
    Type IIA use hyperextension (avoid axial traction in Type IIA)
- Operative
  - reduction with surgical stabilization
    
    indications
    
    Type II with > 5 mm displacement and severe angulation
    
    Type III (facet dislocations)
    
    technique
    
    anterior C2-3 interbody fusion
    
    posterior C1-3 fusion
    
    bilateral C2 pars screw osteosynthesis

Action	Numeric Key	Letter Key	Function Key
Show Bullets		S	Enter (frontside only)
20%	1	N
40%	2	H
60%	3	F	Enter (backside only)
80%	4	E
100%	5	M
Toss	0	T

Levine and Edwards Classification (based on mechanism of injury)
	Mechanism	Characteristics	Treatment
Type I	Axial compression and hyperextension	< 3mm horizontal displacement C2/3 No angulation C2/3 disc remains intact Stable fx pattern	Rigid collar x 4-6 weeks
Type II	Hyperextension and axial load followed by rebound flexion	> 3mm of horizontal displacement Significant angulation Vertical fracture line C2/3 disc and PLL are disrupted Unstable fracture pattern	If < 5 mm displacement, reduction with traction then halo immobilization x 6-12 weeks If > 5mm displacement, displacement, surgery or prolonged traction Usually heal despite displacement (autofuse C2 on C3)
Type IIA	Flexion-distraction	No horizontal displacement Horizontal fracture line Significant angulation	Avoid traction in Type IIA. Reduction with gentle axial load + hyperextension, then compression halo immobilization for 6-12 weeks.
Type III	Flexion-distraction followed by hyperextension	Type I fracture with associated bilateral C2-3 facet dislocation Rare injury pattern	Surgical reduction of facet dislocation followed by stabilization required.