Acute C1-C2 rotatory subluxation in children may be reduced by gentle traction using a head halter. When reduced it can be maintained in a collar.
Depending on the severity of the displacement or time of presentation halo traction may be necessary.
2. Preliminary remark
The halo ring can be placed under local anesthesia in conscious patients. The patient is in a supine position on a stable surface.
The halo ring can be connected to a halo vest to provide stability following closed reduction.
The halo vest has to be sized prior to the procedure.
3. Halo ring installation
The circumference of the patients head is measured and an appropriately sized halo ring is selected.
The ring should allow 1-2 cm clearance from the skull.
Temporary halo fixation
The appropriate halo ring is placed with temporary stabilization pins.
Anterior screws are inserted 1 cm superior to the lateral 1/3 of the eyebrows.
The eyelids should be kept closed.
The posterior screws are placed approximately 5 cm posterior to the ear.
Ideally any posterior screw should be directed towards its contralateral anterior screw, and vice versa.
Care should be taken to prevent contact between the halo ring and the ears.
For adults at least four screws are necessary. For children, 6-8 screws are recommended. The halo ring should be placed inferior to the equator of the skull.
The pin sites are cleaned with a disinfectant and the skin and periosteum is infiltrated with local anaesthesia.
During insertion of the screws, the eyelids of the patient should be kept closed. Screws are inserted into the supraorbital rim with the eyelids open, the patent may not be able to close the eyelids postoperatively.
Initially the permanent screws are tightened by hand, followed by the use of a torque screw driver. Opposing screws are tightened sequentially 1, 2, 3, and 4.
For adults the maximum torque should be set to 0.56 kg/cm3 and 0.28 kg/cm3 for children.
If indicated, a traction ring can be attached at the height of the ears and the halo ring now used for closed reduction by manipulation or over a longer period of time by traction.
The following is needed for a traction setup:
Bed without head plate
Plate with hole for the patients head
Rack with height adjustable pulley
Weights (max 10 kg)
The patient is placed in the bed with the head in the plate opening.
In patients with thoracic kyphosis further padding below the head is used to align the cervical spine.
Note: Most elderly patients have thoracic kyphosis.
Height adjustable stabilizing side brackets are placed and fixed to the caudal side of the ring.
The patients head is adjusted to extension if necessary.
The torso is strapped to the bed to prevent the patient from moving cranially as this might put the cervical spine at risk.
With the bed in the anti-Trendelenburg position, the height of the pulley is adjusted.
Weights are then applied.
Traction is started with 4kg. Control X-rays are used to verify reduction. The weight may be increased till the reduction is achieved with a maximum of 15 kg.
In acute cases, reduction will typically be achieved within 24h and a weight of 4 kg.
4. Attachment to halo jacket
After reduction is achieved and confirmed on X-rays, the halo ring is attached to a halo jacket. Maximum stability is achieved when rods are symmetrical and parallel.
Postoperative X-ray control
X-rays are performed and the position of the spine is checked.
Screw site care
As the screws loosen over time, they should be re-torqued after 24h, 3 days, and then weekly until the halo is removed.
Screw sites should be cleaned daily and the screws replaced in case of loosening or signs of infection.