As mentioned in the previous blog post, the use of halo-gravity traction (HGT) before surgery is a safe and very effective technique to improve severe spinal deformity,
prior to a corrective surgical procedure. On one end of the spine, the head, a carbon-fibre frame is placed onto the skull and a vertical force is placed on the spine via weights and
pulleys. On the other end is simply the patients’ body, so there is a limit as to how much weight we can apply without suspending the patients off the floor!
The other limitation for HGT is that, since body weight is used on the
lower end, the spine deformity we are trying to correct cannot be too low, such
as in the lumbar spine. This is due to
the fact there is less body weight below this area to pull against and hence
hard to change the deformity as much when compared to deformities in the neck
or chest (thoracic spine).
So, can we put a
point of fixation below the area of spine deformity that will allow us to pull
harder, before surgery? The answer is
yes, but the use of preoperative halo-femoral/pelvic/tibial traction has been
shown to have an unacceptably high complication rate (1-3). Despite this the technique has shown to be
effective in preoperatively correcting coronal deformities (41-57%) and pelvic
obliquity (up to 53%) (1-2).
However, we can
use this concept to help improve spinal deformity. The place we can, and do, use this type of
traction is in the operating room during the scoliosis correction surgery. By using this method intraoperatively, one
can avoid the problems associated with long-term traction yet gain the benefits
of direct axial traction during the surgical procedure.
Below is a
patient, during surgery, with a 4-pin halo frame applied (green arrow), which
is attached to a wire bale then to a rope (red arrow) which then goes to a
weight. This applied a pull in the
direction of the red arrow.
On the opposite
end (below), a pin is place across the femur just above the knee joint (green arrow)
and is attached to a bale and rope which then pulls down (direction of red
Both the halo
frame and the traction pin in the femur are placed AFTER the patient is asleep
under general anesthesia, and they are removed BEFORE the patient wakes up
after surgery is completed. Hence, there
is no pain to the patient during the placement or removal of the halo or
The next post
will delve deeper into how we use this type of traction to improve our surgical
C., Perry J., Brown J.C., et al:
Halo-femoral distraction and posterior spine fusion for paralytic scoliosis. J
Bone Joint Surg [Am] 54:202, 1972.
W.J., Moe J.H., Lai C.C.: Halo-femoral
pin distraction in the treatment of scoliosis.
J Bone Joint
Surgery [Am] 49:1018-1019, 1967.
A.O. Manning C.W.: Complications of
halo-pelvic distraction for scoliosis. J Bone Joint Surg [Br]