Halo-gravity traction is a method of gradually lengthening and reducing the curvature of the spines of people with severe spinal deformities caused by scoliosis, kyphosis, kyphoscoliosis, and other medical conditions. While it is most commonly used to treat children and adolescents, halo-gravity traction can also benefit adults with significant spinal curvature.

It involves a surgical procedure in which a surgeon attaches a “halo,” or ring, made of metal, carbon fiber, or other material to the patient’s skull with several metal pins. The halo is then attached to a weighted pulley system that gently pulls the patient’s head and body upward. Every day, a little more weight is added to the pulley system. Over several weeks, halo-gravity traction slowly stretches and straightens the patient’s spine.

Halo-gravity traction is usually used to prepare people for an additional surgical procedure to further correct the curvature of the spine. It reduces the amount of spine curvature that must be corrected in this second surgery and also helps lower the risk of complications of the corrective surgery.

As the name suggests, halo-gravity traction is a form of “traction,” a medical treatment that involves gently pulling a body part over a prolonged period. When used over a one-to-three-month period, halo-gravity traction can safely and effectively lengthen and reduce the degree of curvature of the spines of people with severe spinal deformities.

Halo-gravity traction is used to treat conditions that cause abnormal curvature of the spine, including:

• Scoliosis, a sideways curve of the spine
• Kyphosis, a forward curve of the upper spine that causes a hunched back
• Kyphoscoliosis, a sideways and forward curve of the spine

These conditions sometimes cause severe spinal deformities that make it hard to breathe. This is because the spinal curvature can cause lung development problems and restrict the movement of the ribs, thereby impairing inhalation and exhalation. Gaining and maintaining body weight can also be a problem for people with substantial spinal deformity.

Corrective surgery is the main treatment for people with severe spinal deformities. But, before undergoing corrective surgery, people may be treated with halo-gravity traction to elongate and reduce the curvature of the spine. It can improve breathing, in part, by allowing the ribs to expand. Many people who are underweight at the start of halo-gravity traction successfully gain weight during treatment. Halo-gravity traction can help make corrective surgery less complicated in large part because the spine does not need to be straightened as much. It also reduces the risk of surgical complications.

The halo ring is attached to the patient’s skull in a surgical procedure. General anesthesia is used so the patient will not be awake.

During the procedure, a surgeon screws six to 12 pins into the halo ring then inserts them through the skin and into the skull. The surgeon tightens the pins during the procedure, and they are often retightened a day or two after the initial procedure. The halo surrounds the patient’s head, with about a centimeter or less distance between the head and halo.

The pins are spaced around the patient’s head; in general, more pins are used for younger children. Once in place, the halo sits a little above the eyebrows. The halo itself may be closed, meaning it entirely encircles the head, or open, meaning it has an opening in the back.

Initially after the procedure, patients may have a headache or pain at the pin sites. The pain can usually be treated using acetaminophen, ibuprofen, or other medications and typically goes away within two days.

Once in place, the halo is attached to a weighted pulley system that pulls upward on the head and spine. The pulley system may also be attached to a walker or wheelchair specially designed for use with halo-gravity traction. The amount of weight used for the traction varies based on the patient’s weight.

Usually, children remain in halo-gravity traction for four to 12 weeks, and, in many cases, they stay in the hospital for the duration of the treatment. Adults may need to remain in traction for 6 or fewer weeks. Every day, provided the patient does not experience pain or other side effects (more on that below), a small amount of weight is added—typically one to three pounds—to the traction until the total weight is about 50% of the patient’s body weight.

Patients are monitored daily to check for signs of nerve issues from the traction. This may involve checking vision and hearing, eye movement, shoulder shrugs, and other tests. Every two to four weeks, health providers take X-rays of the spine to assess changes in the curve of the spine.

While in halo-gravity traction, people can use a wheelchair or stand and walk around using a walker. Children can play while in traction and patients can come out of traction temporarily to use the bathroom and take showers. At night, while the patient sleeps, the amount of traction weight may be reduced or removed entirely. A small pillow or rolled-up towel may make sleeping more comfortable.

Physical therapists help patients stay strong physically during treatment, and occupational therapists guide them in learning how to perform everyday tasks while in halo-gravity traction. For patients with breathing difficulties, respiratory therapy may be provided during halo-gravity treatment.

During treatment, a team of additional health care providers, including nurses, dieticians, respiratory therapists, pediatricians and general practitioners, neurologists, orthopaedic surgeons, lung specialists, and psychologists, work together to ensure the best possible outcomes for each patient.

Doctors will determine when to take the patient off halo-gravity traction based on several factors, including the degree to which the curve of the spine has been corrected, the extent of improvement in lung function, and the amount by which the spine has lengthened.

As with any surgical procedure, complications are possible. Most complications that may occur from halo-gravity are minor.

Issues related to the pins that hold the halo in place are common and may include:

• Pin-site infections, which are common and can usually be treated with topical and/or oral antibiotics. In some cases, infections are treated with intravenous (IV) antibiotics. Daily showers can help keep the pins and the surrounding skin clean.
• Pin-site pain and/or headache, which is common for the first 24-48 hours after the halo is placed. Pain medications such as acetaminophen or ibuprofen can help. In most cases, patients don’t feel pain or discomfort once they become accustomed to the device.
• Pin loosening, which may require tightening, exchanging, or removing a pin. Anesthesia may be used during these procedures.

Small scars also form at pin sites after the halo-gravity traction is removed.

During halo-gravity traction, people may experience neck and/or back pain, nystagmus (rapid, uncontrolled eye movement), dizziness, and nausea. Other complications may include muscle weakness and numbness. These complications usually improve when the amount of weight used for traction is reduced.

Halo-gravity traction is a safe method of gradually elongating and straightening the spine of children with severe spinal deformities. It can improve lung function and breathing, and, often, people who previously were underweight due to their spinal problems are able to gain weight.

After undergoing spinal-gravity traction, children and adults typically go on to have surgery to further correct the curve of the spine. Halo-gravity traction can reduce the risk of complications from later corrective spinal surgeries.

“The Pediatric Spine Program at Yale New Haven Children’s Hospital is a destination center for expertise in the management of spinal deformities in children and adults,” says Dominick Tuason, MD, a Yale Medicine pediatric orthopaedic surgeon who treats spinal issues. “Yale offers the latest treatments for even the most complex spinal curvatures. The entire team, from nursing to child life to therapy to the surgeons, has a great enthusiasm for seeing these patients benefit from their treatment course, and is dedicated to delivering the best outcomes possible for patients with truly challenging and potentially debilitating spine conditions.”