What is the Harms technique?

Conclusions: The Harms fixation of C1-C2 is a very effective technique for stabilizing the atlantoaxial complex. It enables us to provide temporary fixation without damage to atlantoaxial joints and to reduce the vertebrae after the screws and rods had been inserted, which is unique.

What is C1-C2 articulation?

The C1-C2 articulation (ie, atlantoaxial articulation) is made up of three joints, including the central atlantoaxial joint and the paired lateral atlantoaxial joints. These joints allow rotation of C1 on C2.

What is high riding vertebral artery?

A high-riding vertebral artery (HRVA) has been defined as a C2 isthmus height of ≤5 mm and/or internal height of ≤2 mm measured 3 mm lateral to the border of the spinal canal. If overlooked during the approach for craniocervical fusion, injury to the vertebral arteries can occur, affecting the outcome.

How do you place a lateral mass screw?

In Anderson technique, the entry point for screw insertion is located 1 mm medial to the midpoint of the lateral mass. The direction of the screw is 30–40° superiorly and 10° laterally. In a technique, the entry point for screw insertion is located 1 mm medial to the midpoint of the lateral mass.

Why are C1 and C2 special?

C1 and C2 Anatomy The C1 and C2 vertebrae are uniquely shaped and have vertebral foramen (spaces within the bone) which allow the vertebral arteries and veins to reach through to the brain and supply it with blood. This unique formation is only seen in the cervical vertebrae.

What is Ponticulus Posticus?

The ponticulus posticus is a bony bridge in the first cervical vertebra between the lateral mass and the posterior arch. It results due to ossification of the posterior atlanto-occipital ligament of atlas and encloses the vertebral artery and the first cervical nerve root [6].

What is cervical lateral mass?

The lateral mass is the bony junction between the superior and inferior articular processes, separated medially from the lamina by the medial facet line (a sulcus at the junction of the lamina and facet).

Where is Odontoid process?

The odontoid process (also dens or odontoid peg) is a protuberance (process or projection) of the Axis (second cervical vertebra). It exhibits a slight constriction or neck, where it joins the main body of the vertebra.

Why can injuries at C1 or C2 be fatal?

Severe cases of spinal cord injury at C2 can be fatal because breathing and other critical body functions may be impaired or stop. Paralysis of the body below the injured region of the spinal cord may also occur in some cases.

What happens if you break your C1 and C2?

A C1 through C2 vertebrae injury is considered to be the most severe of all spinal cord injuries as it can lead to full paralysis—but is most often fatal. Depending upon their severity, these types of spinal cord injury are either categorized as complete or incomplete.

When did harms develop the C1-C2 stabilization technique?

In 2001, Harms developed Goel’s work on atlanto-axial screw fixation, describing a stabilization technique based on fixation of the C1 lateral masses and C2 isthmus using polyaxial screws.

What are the disadvantages of C1 C2 fixation?

The disadvantage is that screw insertion requires fluoroscopy. Furthermore, the C2 pars must be large enough to accommodate a 3.5 mm diameter screw. Pitfall: Too ventral an angulation of the screw can risk injury to the vertebral artery. 4.

How are C1-C2 fusion complications are common?

She was diagnosed with CCI due to a car crash and had moderate instability on her DMX and evidence on MRI of alar/transverse ligament injury. She underwent C1-C2 screw fixation where a screw was placed through the C1-C2 joint to fuse it and to reduce her instability.

When to use C1-C2 posterior cervical fixation?

C1-C2 posterior fixation is indicated in the occurrence of instability at the craniocervical junction; and it can be performed by specific surgical techniques, such as the Harms and Magerl techniques.

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