questions
5

Atlas Fracture & Transverse Ligament Injuries

Author:
Topic updated on 05/18/14 11:11am
Introduction
  • Epidemiology
    • make up ~7% of cervical spine fractures
    • risk of neurologic injury is low
    • commonly missed due to inadequate imaging of occipitocervical junction
  • Pathophysiology
    • mechanism
      • includes hyperextension, lateral compression, and axial compression
  • Associated conditions
    • spine fracture
      • 50% have an associated spine injury
      • 40% associated with axis fx
  • Prognosis
    • stability dependent on degree of injury and healing potential of transverse ligament
Anatomy
  • Bony anatomy
    Atlas osteology
    • atlas (C1) is a ring containing two articular lateral masses
      • it lacks a vertebral body or a spinous process
      • embryology
        • forms from 3 ossification centers  
      • anatomic variation
        • incomplete formation of the posterior arch is a relatively common anatomic variant and does not represent a traumatic injury  
  • Ligamentous anatomy
    • occipital-cervical junction and atlantoaxial junction are coupled
    • intrinsic ligaments are located within the spinal canal, provide most of the ligamentous stability. They include
      • transverse ligament  
        • primary stabilizer of atlantoaxial junction
        • connects the posterior odontoid to the anterior atlas arch, inserting laterally on bony tubercles. 
      •  paired alar ligaments  
        • connect the odontoid to the occipital condyles
        • relatively strong and contributes to occipitalcervical stability
      • apical ligament  
        • relatively weak midline structure
        • runs vertically between the odontoid and foramen magnum.
      • tectorial membrane 
        • connects the posterior body of the axis to the anterior foramen magnum and is the cephalad continuation of the PLL
  • atlas (C1) is a ring containing two articular lateral masses
    it lacks a vertebral body or a spinous process
    anatomic variation
    incomplete formation of the posterior arch is a relatively common anatomic variant and does not represent a traumatic injury
    Ligamentous anatomy
    intrinsic ligaments are located within the spinal canal, provide most of the ligamentous stability. They include
    tectorial membrane (most dorsal layer) 
    connects the posterior body of the axis to the anterior foramen magnum and is the cephalad continuation of the PLL
     transverse ligament is the strongest component 
    connects the posterior odontoid to the anterior atlas arch, inserting laterally on bony tubercles.  
     paired alar ligaments 
    connect the odontoid to the occipital condyles
    relatively strong
    apical ligament
Classification
 
 Atlas Fractures Classification
Type I Isolated anterior or posterior arch fracture. A "plough fracture is an isolated anterior arch fracture caused by a force driving the odontoid through the anterior arch.
Type II Jeffereson burst fracture with bilateral fractures of anterior and posterior arch resulting from axial load. Stability determined by integrity of transverse ligament.
Type III Unilateral lateral mass fx. Stability determined by integrity of transverse ligament.  
 
Transverse Ligament Injuries Classification
Type I Intersubstance tear
Type II Bony avulsion
 
Imaging
  • Radiographs
    • lateral radiographs
      • atlantodens interval (ADI)
        • < 3 mm = normal in adult (< 5mm normal in child) 
        • 3-5 mm = injury to transverse ligament with intact alar and apical ligaments 
        •  > 5 mm = injury to transverse, alar ligament, and tectorial membrane 
    • open-mouth odontoid
      • open-mouth odontoid view important to identify atlas fractures
      • sum of lateral mass displacement 
        • if sum of lateral mass displacement is > 7 mm (8.1mm with radiographic magnification) then a transverse ligament rupture is assured and the injury pattern is considered unstable q q
  • CT
    • study of choice to delineate fracture pattern and identify associated injuries in the cervical spine 
  • MRI
    • more sensitive at detecting injury to transverse ligament 
Treatment
  • Nonoperative
    • hard cervical orthosis vs. halo immobilization for 6-12 weeks 
      • indications
        • stable Type I fx (intact transverse ligament)
        • stable Jeffferson fx (Type II) (intact transverse ligament)
        • stable Type III (intact transverse ligament)
      • technique
        • controversy exists around optimal form of immobilization
  • Operative
    • posterior C1-C2 fusion vs. occipitocervical fusion 
      • indications
        • unstable Type II (controversial)    
        • unstable Type III  (controversial)
      • technique
        • may consider preoperative traction to reduce displaced lateral masses
Techniques
  • Posterior C1-C2 fusion
    • preserves motion compared to occipitocervical fusion
    • fixation
      • C1 lateral mass / C2 pedicle screw construct
        • may be sufficient if adequate purchase with C1 lateral mass screws
      • C1-2 transarticular screw placement
  • Occipitocervical fusion
    • uses when unable to obtain adequate purchase of C1
    • leads to significant loss of motion 
Complications
  • Delayed C-spine clearance
    • higher rate of complications in patients with delayed C-spine clearance so it is important to clear expeditiously

 

Please Rate Educational Value!
4.0
Average 4.0 of 26 Ratings

Qbank (5 Questions)

TAG
(OBQ12.255) A 35-year-old patient sustains a bilateral anterior and posterior arch (C1) injury with an intact transverse ligament. Which of the following treatment options is most appropriate? Topic Review Topic

1. Observation alone
2. Soft collar orthosis for 4-6 weeks
3. Occipitocervical fusion
4. Rigid collar orthosis for 6-12 weeks
5. Posterior C1-C2 fusion

PREFERRED RESPONSE ▶
TAG
(OBQ10.71) Figure A shows the coronal and axial CT images of a 27-year-old male that suffered a fall from a significant height. Which of the following radiographic measurements would best indicate disruption of the transverse ligament? Topic Review Topic
FIGURES: A          

1. Atlantodental interval (ADI) of 2mm
2. Posterior atlanto-dens interval (PADI) of 16mm
3. C2 pars horizontal displacement of 3 mm
4. Combined lateral mass displacement of 8.2mm
5. A Power's ratio of 1.2

PREFERRED RESPONSE ▶
TAG
(OBQ05.67) A Gallie C1-2 fusion with sublaminar wiring of C1 to the spinous process of C2 is a valid treatment option for which of the following injury patterns? Topic Review Topic

1. occipital-cervical dissociation
2. comminuted C1 burst fracture
3. type I odontoid fracture
4. type III odontoid fracture
5. transverse ligament disruption

PREFERRED RESPONSE ▶
TAG
(OBQ04.176) Biomechanical studies have shown that an atlanto-dens interval of >7mm is likely associated with? Topic Review Topic

1. an intact transverse ligament, with ruptured alar and apical ligaments
2. a ruptured transverse ligament, with intact alar and apical ligaments
3. a ruptured transverse and apical ligament, with an intact alar ligaments
4. a ruptured transverse and alar ligament, with an intact apical ligaments
5. a ruptured transverse and alar ligament, and a ruptured tectorial membrane

PREFERRED RESPONSE ▶
Sorry, this question is available to Virtual Curriculum members only.

Click HERE to learn more and purchase the Virtual Curriculum today!





Cases

http://upload.orthobullets.com/cases/1159/img_0133.jpg http://upload.orthobullets.com/cases/1159/img_0131.jpg http://upload.orthobullets.com/cases/1159/img_0132.jpg
HPI - The patient is 43 year old gentleman, who was assaulted and placed in a head loc...
poll How would you treat this patients? Keep in mind we are in Nicaragua, and th...
2/22/2012
146 responses
3
See More Cases

Videos

video
Length: 30 minutes This is a review video highlighting the important aspects of...
5/18/2013
372 views
4
See More Videos

Posts

Groups


Evidence & References Show References




Topic Comments