Spine – Halo Application
With the exception of component size and pin torque, halo-brace application for children requires similar hardware and technique to adult application
Pin Site Selection
– anterior safe zone – 1 cm superior to orbital rim (eyebrow) at the lateral two thirds of the orbit and below the equator of the skull. Keeping it a centimeter above the orbital rim prevents putting the pin into the orbit, and keeping it below the equator prevents cephalad migration of the pin. The danger in the medial two thirds of the orbit are the supratrochlear nerve and artery most medial, and the supraorbital nerve and artery just lateral to that, and the frontal sinus beneath the cortex.
– lateral to the anterior safe zone is the temporalis muscle and fossa – avoid this area; the bone is very thin, and putting a pin through the muscle may block mandibular motion.
– posterolateral pin placement is less critical because major structures are out of the way – best is at about the 4 and 8 o’clock positions.
Do not use skin incisions – shave, prep, infiltrate local anesthetic, and bang the screw in
Ring size: select or custom make a ring about 2 cm larger in diameter than the head
Jacket size – may need a custom vest, or can fashion a body cast – Get help with this!
In the child, the recommended pin torques are between 2 and 5 inch/lb – go LOW TORQUE with MORE PINS
Get a CT scan to show you the bony thickness of the various regions of the skull
In children younger than 3, a multiple pin (8 to 12), low torque technique is recommended to allow a greater range of pin placement sites in areas where the infant skull might be too thin or too weak
You have to consider that the skull is still growing – cranial distortion ad bone shifting can be minimized by short periods of halo application, curstom-fited halo rings, and evenly distributed, low cranial pressure accomplished through multiple pins. (ie – best to have lots of pins at 2 inch/lb torque than a few at 5 inch/lb torque).
Loosening – the loose pin and remaining pins are retightened to 2 inch/lb, as long as resistance is met with the first two complete rotations of the pin. If no resistance is met, place a pin at a different site and take this one out. (this is why lots of pins in a child is good – the construct is not so dependent on one pin)
Infection – pins should undergo daily pinsite care – NS swabs QID. If drainage starts, culture and begin on oral antibiotics. If not responsive, or if cellulitis or abscess develop, then take the pin out and start IV antibiotics.
Dural Puncture – may occur if they fall on the halo, or if you tighten it through the inner table
– may complain of headache, malaise, visual disturbances, nausa, vomiting
– look for CSF leaking around the pinsite
– hospitalize, start prophylactic IV antibiotics, and remove the pin after putting another new pin in at a different site.
– elevate head of bed
– if leak does not respond or a subdural abscess develops, it needs surgical exploration and dural repair.
Loss of Reduction – check the vest!