The document discusses various surgical techniques for cervical spine stabilization at C1-C2. It describes the anatomy of the atlantoaxial joint and its range of motion. Various fixation techniques are covered, including Magerl transarticular screws, C1 lateral mass screws, C2 pars screws, C2 pedicle screws, and C2 laminar screws. Entry points and trajectories for each technique are detailed. Potential risks and variations are also noted. The importance of preoperative imaging to evaluate anatomical variations is emphasized.

1. SURGICAL TECHNIQUES
IN CERVICAL SPINE
STABILIZATION
Manish Vaish

3. C1
C2
Dens
Zygapophyseal
joints
The articulation of the ATLANTOAXIAL
JOINT between the atlas (C1) and the
axis (C2) has a range of motion in the
transverse plane for rotation.
The DENS of C2 acts as a pivot
point for the rotation of C1.
The articulating surfaces of the two
vertebrae form the
ZYGAPOPHYSEAL (FACET) JOINTS
that allow flexion-extension, side
bending, and rotational movements.

4. Axial View
Transverse
ProcessBody
Sulcus for
Spinal Nerve
Lateral
Mass
Lamina
Pedicle
Superior
Articular Facet
Vertebral
Foramen
Bifid Spinous Process
Transverse
Foramen

5. Sulcus for
Spinal Nerve
Uncinate
Process
Uncovertebral Joint
(Joint of Luschka)
Anterior View

6. 45° to the axial plane
In the cervical region, the facet joints are flat
and oriented 45° to the horizontal. This means that
the cervical region has a significant range of motion
in the six degrees of freedom.

9. 14year/male
After RTA in FEB 2011 and presented to FHN in
May 2011 with
Pain in neck movements which progressed to
inability to move neck
Quadriparesis

11. 35 years/male H/O RTA admitted with
Painful neck movements
Difficulty in walking

18. 58 years male
K/C/O Rheumatoid arthritis for 13 years
Quadriparesis 20 days
Operated twice(2007,2009) with C1 posterior
arch excision with C0 C2 fusion and revision
done with C3 C4 laminectomy

25. Atlantoaxial dislocation
reducible
irreducible
Type II #
Odontoid screw
Magerl or Various C1-2 screw fixation
Occiput-Cervical fusion
Anterior compression
Anterior
decompression
No compression
C1 laminectomy
fragile C1 lamina
Failed C1-2 fusion
Occipitalised atlas
C1 post elements #

26. Magerl transarticular Screws
C1 lateral mass screw
C2 pars screw
C2 pedicle screw
C2 laminar screws
Hybrid wire and screw fixation

28. Source: Medscape, MyAANS

29. Entry point in line with the medial edge of the
lamina origin
Direction of screws

30. The average length of screw adjacent to the
lamina is 1cm and within the lateral massis
upto 2 cm

31. The Harms technique
The entry point for placement of a C2 pedicle
screw was 2 mm from the medial border and 5
mm from the caudal border of the C2 articular
process.
The trajectory is at an angle of 20 to 30
degrees cranially, and in the transversal plane,
the screws were directed medially at an angle
of 20 to 25 degrees

32. Lateral mass
25º
Trans Artricular
45º
Pedicle
1mm medial
1-2 mm cephalad

35. • CT Scan
Madawi AA, Casey AT, Solanki GA, Tuite G, Veres R, Crockard HA :
Radiological and anatomical evaluation of the atlantoaxial transarticular
screw fixation technique. J Neurosurg 86 : 961-968, 1997

41. Image guided spinal surgery
C1-C2 TRANSARTICULAR SCREWS

42. LEFT C1-C2 RIGHT C1-C2
ENTRY POINT
TARGET POINT
Image guided spinal surgery

43. Image guided spinal surgery
C1-C2 TRANSARTICULAR SCREWS

44. Destruction of C1 lateral mass/ fracture or
destroyed C2 pars interarticularis
Large Vertebral Artery groove
Irreducible subluxation
Aberrant Vertebral Artery
Occipitalized atlas (relative)
Following transoral odontoidectomy
(relative)

45. Mal position of screws
Implant failure
Spinal cord / dura/ 12th injury
Vertebral Artery injury

49. A C2 pars screw is placed in a trajectory similar
to that of a C1-C2 transarticular screw except
that it is much shorter
Screw length is typically 16 mm, stopping
short of the transverse foramen
.

51.  Because the trajectory of this technique is more superior and
medial than the transarticular screw fixation, potential risk of
vertebral artery injury is lower
 Intraoperative reduction of the C1-C2 complex can be
accomplished by direct manipulation of C1 and C2.
 The polyaxial screws can be joined to the occiput and subaxial
cervical spine.
 Temporary fixation of the C1-C2 complex is possible, because
this technique does not damage the C1-C2 facet joint

52. Wright NM : Posterior C2 fixation using
bilateral, crossing C2 laminar screws : case
series and technical note. J Spinal Disord Tech
17 :158-162, 2004
Leonard JR, Wright NM : Pediatric atlantoaxial
fixation with bilateral, crossing C-2
translaminar screws. Technical note. J
Neurosurg 104 : 59-63, 2006

53. Entry point spine-lamina junction
Directed towards lamina-facet junction
Average 30mm long

55. Roy-Camille
Variations in
entry point,
trajectory
An technique
lowest risk of
nerve root
injury
screw
</=15mm

56.  3 column fixation (A)
 Superior to lateral mass
screws (biomechanical)
 Preop CT: bones, verts,
nn.
 Enter lateral to center of
facet, close to post margin
of superior articular
surface
 Point of entry
decorticated with high
speed drill
 Angles vary (B, C)

57.  These three techniques provided equivalent
stability to the C1 to C2 complex in flexion-
extension and axial rotation
 C1 lateral mass-C2 laminar screw technique
provided slightly less stiffness than other
techniques in lateral bending
 pedicle screws provide the strongest fixation for
both initial and salvage applications. If they
should fail, lamina screws appear to provide
stronger and more reproducible fixation than pars
screws.

58.  Dissection is carried to the tips of the transverse processes
 Attention is given to the preservation of the most
cephalad facet capsule while all other soft tissue is
removed from the facet
 The peri-spinal musculature is retracted for intra-canal
work
 Appropriate laminotomies and/or laminectomy may be
performed
 Attention is now directed toward instrumentation of the
spine

62. The anatomy of the C2 is highly variable.
 It is essential to routinely perform a CT an
individually evaluate every screw tract to
provide the safest option.
 Knowledge of the various techniques
described are useful when dealing with
instability in the craniovertebral junction

63. THANKS VERY MUCH