1. The OccipitoCervical Fixation
Bernucci Claudio, M.D.
Head of Neurosurgery Unit
Department of Neuroscience and Surgery of the Nervous System
ASST Papa Giovanni XXIII– Bergamo

2. The Cranio-Cervical Junction (CCJ)
More than 50% of the rotation and flexion-extension of the head and neck occurs in CCJ. It permits movements in eight axes of rotation. These include flexion, extension, bilateral lateral bending; and bilateral rotation, distraction, and axial loading. The motion of the AO junction is dictated by osseous constraints, whereas stability of the AA articulation is provided primarily by ligament restraints Intrinsic ligaments (tectorial membrane, cruciate & alar ligaments) & joint capsules provide most of the stability of the CCJ: the rest is provided by extrinsic ligaments

3. Indications for OC fixation
Occipitocervical arthrodesis is indicated to treat instability of the CCJ
The causes of occipitocervical and atlantoaxial pathology include:
CCJ Trauma (more common in the paediatric population)
Rheumatological diseases (Rheumatoid arthritis)
Tumor
Infection
Congenital malformation (Chiari malformation, Os odontoideum, osteogenesis imperfecta)
Degenerative disease processes
OC fusion blocks all the movement of the CCJ: it is best to prefer more conservative treatment as a first option

4. Signs of CCJ Instability

5. OC Fixation - Techniques
Fusion success rates as high as 100% using plate and screw fixation have been reported by Smith et al and Sasso et al. Occipital wire and rod constructs are less stable especially under axial loads The methods noted to be the most stable were screw fixation techniques that include C2.

6. Surgical planning: what do you need to know?
Angio-CT: vertebral artery CT: C1 lateral mass lenght and orientation, C2 pedicle lenght and diameter, isthmic point , occipital bone thickness

7. Positioning

8. Positioning Shoulders raised and pulled caudally
Spine parallel to the floor
Head flexed
Check the caudo-cranial trajectory for C2 screwing
with a kirschner pin and X-rays

9. Head positioning
The OC fusion does not allow all the movements of the upper cervical spine. Therefore it is mandatory to place the head in order to allow for horizontal gaze Place the patient in the prone position with the head fixed in a 3-pin head-clamp.
First, it is best to put the head slightly flexed in order to open the space between vertebrae.
Once the screws are inserted it is better to slightly extend the head in order to avoid kyphotizing the spine.

10. it is an anatomical procedure based on surgical landmark
Intraoperative X-rays useful, but not reliable helps in antero-posterior lenght and caudo-cranial direction for C1 screws helps in caudo-cranial direction for C2 screws (parallel and tangent to the upper margin of the C2 pedicle)
it is an anatomical procedure based on surgical landmark
….unless O-ARM

11. The Occipital Bone
The occipital squama bone thickness is the greatest at the external occipital protuberance (EOP) and decreases in a radial distribution
Bone thickness in the EOP is 15 mm in males and 12 mm in females on an average. The other “safe area” is relatively thin strips of bone that extends caudally from the EOP and is a reflection of the internal occipital crest.
Suchomel P, Choutka O : Reconstruction of Upper Cervical Spine and Craniocervical Junction

12. Case 1
A 6-year-old female with no prior medical history was brought to the emergency room after a high energy car accident, complaining:
Paraplegia
Weakness (0/5) of the right upper limb
Severe neck pain
Respiratory distress
The imaging showed an Atlanto-Occipital Dissociation

17. C1, C2 fixation with Goel-Harms technique and C4 transarticular screw insertion