Cervical Spine Trauma Odontoid fractures Anatomic pathology Management options Case Illustrations Kevin Chao, MD November 8, 2010

Anatomy: Supra axial cervical spine

Anatomy: Supra axial cervical spine ALL -> anterior atlanto-occipital membrane PLL -> tectorial membrane (16) 7 - > apical ligament 8 -> vertical cruciform ligament15 -> transverse ligament

Odontoid Fractures Epidemiology Mechanism: Flexion injury 10-15% of c-spine fractures 30-40% associated fatality Type II ~10% with deficits Mechanism: Flexion injury Often subsequent C1-C2 subluxation Symptoms: high cervical pain, reduced ROM, tenderness to palpation Transverse ligament injury  instability

Treatment guidelines Non operative Operative Types I and III Halo or SOMI brace Follow up imaging 6 weeks Operative Type II Especially in pts age > 50 (~30% non union rate) Fracture displacement ≥ 5 mm Neurologic deficit Comminution Failed alignment or malunion with external fixation

Surgical Options Anterior fusion Posterior fusion Odontoid screw fixation Posterior fusion Wiring/fusion techniques Gallie fusion Brooks fusion Locksley Tie Bar Dickman-Sonntag Plates/clamps Halifax clamps Hook plates Transarticular screw C1-C2 articular fusion Harm’s C1-C2 construct Occipital-cervical fusion Combined anterior-posterior fusion

Odontoid screw Indications: Contraindications: Union rate 95% Reducible Type II dens fx Intact transverse ligament Fracture < 6 months old Contraindications: Large fracture gap Irreducible fracture Pathological fracture Oblique fracture line Union rate 95%

Wiring/fusion techniques Gallie “H” graft between C1-C2, C1 and C2 sublaminar wire Brooks 2 wedge bone grafts with C1 to C2 sublaminar wires (75-85% union)

Wiring/fusion techniques Dickman-Sonntag 1 wedge bone graft with sublaminar wire under C1 (97% union) Locksley Tie bar 3 point posterior fixation

Transarticular screw Immediate stabilization Wire entry needs “flat” angle Entry point Traverse facet joint Target superior aspect of C1 anterior arch Risk for vertebral artery injury

Harms C1-C2 Posterior Fusion C1 lateral mass - C2 pedicle polyaxial screws and bilateral rod fixation Anatomic advantages Immediate stabilization Technical Notes: Proud C1 screw Superior-medial entry of C2 screws Rotational reduction after screw placement Optional posterolateral fusion

Non-union Clinical signs and symptoms Continued high posterior cervical pain Late myelopathy Radiographic criteria Contiguous sclerosis of fractured fragments Contiguous resorption of fractured fragments Loss of cortical continuity Movement on dynamic films

Spine Fracture Approach Assessment Mechanism of injury Neuro exam Imaging Levels Bone vs soft tissue Dynamic vs static Vessels? Degree of instability Management Surgery vs no surgery Goals? Brace? Activity restrictions Follow up Imaging Rehab

Case files

Case 1

Case 2

Left vert out

Case 3

Case 4

Case 5

Small pedicles

Mary had a little lamb, Its fleece was white as snow Everywhere that Mary went The lamb was sure to go It followed her to school one day Which was against the rules. It made the children laugh and play To see a lamb at school And so the teacher turned it out, But still it lingered near And waited patiently about Till Mary did appear "Why does the lamb love Mary so?" The eager children cry "Why, Mary loves the lamb, you know." The teacher did reply