This document discusses surgical techniques for C1-C2 fixation, including posterior C1-C2 polyaxial screw and rod fixation, C1-C2 transarticular facet screws, and C1-C2 wiring fixation. It provides details on patient evaluation, surgical procedure, risks, and outcomes for each technique. Atlantoaxial instability can result from fractures, rheumatoid arthritis, or congenital anomalies and these fixation techniques are used to maximize stability and achieve arthrodesis between C1 and C2. Wiring techniques are less challenging than screw-based approaches but require an intact posterior arch and halo immobilization.

1. Dr. FARRUKH JAVEED

2.  C1 – C2 Screw Fixation
 C1 C2Wiring Fixation
2

3.  To maximize
atlantoaxial stability
 To achieve successful
arthrodesis betweenC1
and C2

4. 4

5. 5

6. 6

7.  Posterior C1-C2 Polyaxial Screw and Rod Fixation (Harms
Technique)
 C1 lateral mass – C2 pedicle or pars fixation
 C1-C2Transarticular Facet Screws (MagerlTechnique)
7

8. 8

9.  Atlantoaxial instability resulting from
 Fractures of the odontoid (types II and III) (Figs. 11.1 and 11.2)
 Adjacent fractures of C1 and C2
 Rotatory subluxation
 Rheumatoid arthritis
 Os odontoideum
 Postodontoidectomy without basilar invagination
 Congenital malformation (i.e, Klippel-Feil)
 Malignancy
9

10.  Non-unions
 Odontoid nonunion (types II and III)
 Failed posterior C1-C2 fusion
 C1-C2 osteoarthritis
10

11.  Vertebral artery injury ( avoid ipsilateral side)
 Aberrant vertebral artery course
 High-ridingC2 transverse foramen
 Significant anterior cord compressive
pathology
 Small C2 pars or pedicles
 Lateral mass fractures of atlas or axis
 Severely obscured bony anatomy due to
destructive or erosive pathology

12.  Detailed neurological and musculoskeletal examination.
 Preoperative imaging should include plain radiographs,
computed tomography (CT), CT angiography, and magnetic
resonance imaging (MRI) of the cervical spine.
12

13.  Radiographs should include anteroposterior (AP), lateral, and
open mouth.
 Combined lateral mass displacement in excess of 7 mm or an
atlantodens interval (ADI) greater than 3 mm suggests
transverse ligament disruption.
13

14. 14

15.  Axial, sagittal, and coronal thin-cut (1-mm) reconstruction
images.
 Accurate detail of the bony anatomy.
 Position of the foramen transversarium through which the
vertebral artery runs.
 Measurement of the length of the screws
15

16. 16

17.  Visualization of any soft tissue injuries (ligaments injury,
spinal cord injuries)
 Useful in rheumatoid patients (soft tissue pannus formation)
 MR Angiogram can be used to evaluate vertebral artery injury,
patency, and/or dominance.
17

18. 18

19.  Intubation with fibro-optic guidance
 Pre-op anteroposterior (AP) and lateral fluoroscopic
radiographs
 Stereotaxy
 Intra-operative electrophysiological monitoring
 Somatosensory evoked potentials (SSEPs)
 Motor evoked potentials (MEPs)
 Short acting muscle relaxants
19

20.  The patient is kept prone in a
Mayfield head holder.
 The neck is placed in a neutral
position.
 Inion to the mid-cervical spine.
20

21.  If a definitive fusion is being performed, the posterior iliac
crest is also shaved and draped for bone graft harvesting.
 The midline is identified and marked from the occiput to C3-
C4 with a sterile marker.
 Careful subperiosteal dissection is continued from C3 to C1,
starting in the midline and proceeding laterally.
21

22.  C2-3 facet joints are exposed (but not
violated), and the dorsal arch of C1 is
exposed laterally.
 The C2 nerve root is identified and is
typically mobilized inferiorly.
22

23.  The inferior third of the C1 lamina is
removed with a high-speed drill.
 The entry point for the C1 lateral mass
screw is identified at the center of the C1
lateral mass.
23

24.  A low-speed drill with a 3-mm-
diameter drill bit and guide is seated
on C1 lateral mass entry point, and
under fluoroscopy a pilot hole is
drilled through the C1 lateral mass.
 The trajectory of the pilot hole is 10
degrees medial angulation in the axial
plane and in parallel with the ring of
C1 in the sagittal plane.
24

25.  The pilot hole is tapped with a 3.5-mm tap,
and a 4.0-mm diameterC1 lateral mass
screw is placed.
 Typical dimensions for a C1 lateral mass
screw are 4.0 mm wide and 36 mm long.
25

26.  The C2 screw can be placed in the pars of
C2, in the pedicle of C2, or in the lamina of
C2.
 We place bone graft (usually iliac crest
tricortical autograft) in the interlaminar
space between C1 and C2 or laterally in the
facet joint of C1-2 or along the lateral
lamina and pars of C1 and C2 (onlay graft).
26

27.  the entry point is slightly
lateral (3 mm) to the lamino-
inferior articular process
junction, and 2 to 3 mm cranial
to the inferior articular facet of
C2.
 Direction is 25- to 30-degree
cranially and up to 10 degrees
medially.
27

28.  Entry point is about 6 mm
lateral from the lamino-
articular junction.
 The trajectory is angled
medially 25 to 30 degrees and
cranially ~ 25 degrees.
28

29. 29

30. 30

31. 31

32. 32

33. 33

34.  Vascular injury (vertebral arteries)
 Spinal cord injury
 Nonunion
 Instability
 Adjacent segment disease
 Hematoma
 Cerebrospinal fluid leak
 Painful anesthesia from C1 or C2 ganglion injury

35. 35

36.  Atlantoaxial wiring can be performed to eliminate instability
for the following indications:
 Fractures of the odontoid (type II and III)
 Select fractures of C1 and C2
 Rotatory subluxation
 Rheumatoid arthritis
 Os odontoideum
 Postodontoidectomy without basilar invagination
36

37.  Absent posterior element of either C1 or C2
 Atlas assimilation
 Severe osteoporosis
37

38.  Simple and inexpensive procedure
 Relatively easy exposure
 Very low or no risk of vertebral artery injury in patients with
ectatic vertebral artery
 May be useful in patients with hypoplastic pars interarticularis
38

39.  Requires an intact posterior arch of C1 andC2.
 Cannot be performed when posterior decompression of the
C1-C2 complex is required or in the presence of significant
osteoporosis.
 Potential for injury to the dura or spinal cord.
 Fixation is only semi-rigid and it is least effective for axial
rotation.
 Postoperative bracing is necessary (rigid orthosis or optimally
a halo vest) to optimize the fusion rate.
39

40.  Three basic cable/wire fixation
 Common techniques for C1-C2 fixation:
 the Gallie,
 the Brooks,
 and the interspinous technique
40

41. 41

42.  First described in 1939
 Can become unstable due to
rotational forces.
42

43.  In 1978, Brooks and Jenkins refined the Gallie technique by
utilizing sublaminar wires at C1 and C2 with an interlaminar
wedge bone graft.
43

44. 44

45.  Immobilize the patient in a halo-vest orthosis for 6 to 12
weeks after surgery.Then, flexion and extension radiographs
should be obtained to assess the fusion.
 If there is no motion, the halo can be removed.
 The patient should be followed clinically and radiographically
until fusion has occurred.
45

46.  Non union upto 30%.
 Iatrogenic fracture of the posterior arch
 Risk of dural tear
 Neurological deficit.
46

47.  C1-C2 posterior wiring techniques are relatively less
challenging as compared with other newer screw-and-rod–
based techniques.
 Even though the wiring techniques are not as rigid as screw
based techniques, they do offer higher rates of fusion when
combined with halo immobilization.
 However, they require an intact posterior arch of C1 and C2,
which is not always available.
47

48. 48