Scoliosis is a condition characterized by an abnormal side-to-side curvature of the spine, often resembling an “S” or a “C” shape. While many cases are managed with observation or bracing, the most severe and rigid spinal deformities require a specialized intervention. Halo-Gravity Traction (HGT) is a non-surgical technique designed to gradually and safely stretch the spine. This method is primarily used as a preparatory step for patients with the highest degree of curvature before they undergo definitive corrective surgery.
How Halo Traction Reduces Severe Curves
The core function of the halo device is to apply constant, gentle vertical force, utilizing the principles of traction to lengthen the compressed spine. This is achieved through a lightweight, metal ring, or “halo,” which is securely attached to the patient’s skull and connected to a pulley system with weights. This system slowly and continuously pulls the head upward against the force of gravity and the patient’s body weight.
This gradual stretching relies on the viscoelastic properties of the vertebrae and surrounding soft tissues. Over a period of weeks to months, the constant pull elongates the ligaments, muscles, and intervertebral discs, making the rigid spine more flexible. The goal is not to achieve the final correction but to “soften” the spine, reducing the spinal curvature by up to 30–40% before surgery. This preparation makes the spine safer and easier to manipulate during the subsequent surgical procedure.
Determining When Halo Traction is Necessary
Halo-Gravity Traction is reserved for the most extreme cases of spinal deformity, where the curvature is too severe or too stiff to correct safely in a single surgery. The treatment is typically indicated for patients with major curves exceeding 90 to 100 degrees, often in combination with a high degree of rigidity. Rigidity refers to the spine’s inability to passively correct itself when positioned differently, making it resistant to immediate surgical straightening.
The decision to use HGT hinges on minimizing the risk of neurological damage during surgery. By slowly stretching the spine, the traction allows the spinal cord and surrounding nerves to accommodate the change in length over time. Patients remain hospitalized for the entire duration, typically three to twelve weeks, allowing for close medical monitoring and weight adjustments.
Living with the Halo System
The process begins with the surgical placement of the halo ring under general anesthesia. A surgeon secures the metal ring to the skull using several small pins, usually six to twelve, which penetrate the skin and anchor into the outer table of the bone. The number of pins used often depends on the patient’s age and bone quality, with more pins sometimes used for younger children to distribute the force.
Once the halo is in place, it is connected to a pulley system on the patient’s bed, wheelchair, or walker, enabling the constant application of traction. The medical team starts with a small amount of weight, typically 2 to 4 kilograms, and gradually increases it by one to three pounds daily as tolerated. The total weight applied can reach up to 50% of the patient’s body weight to maximize the stretching effect.
Meticulous pin site care is required to prevent infection, which is a common, though usually minor, complication. Care involves regular cleaning and monitoring the sites for any signs of redness or discharge, often with the help of specialized nurses. Patients are encouraged to be mobile, using special walkers or wheelchairs that maintain the traction, as standing and walking enhance the therapeutic effects of gravity.
Neurological checks are performed frequently, especially when increasing the weight, to ensure the spinal cord is not being overstretched. While some discomfort, such as headaches or mild pin-site pain, is common in the first couple of days, many patients quickly adapt. The gradual straightening can lead to immediate benefits, such as improved lung function and easier breathing.
Transitioning to Surgical Correction
Halo-Gravity Traction maximizes the safety and efficacy of the subsequent spinal fusion surgery. By stretching the spine and making it more flexible, HGT significantly reduces the technical difficulty of the operation. This preparation lowers the likelihood of severe complications, particularly neurological injury, which is a major concern when attempting to rapidly correct a rigid, severe curve.
The period of traction is complete when the spine reaches its maximum safe flexibility, determined through regular X-rays and clinical assessments. Once the medical team confirms that no further safe correction can be achieved through traction, the patient is prepared for the definitive surgery. The halo device is typically removed either immediately before or during the spinal fusion procedure, allowing the surgeon to proceed with permanently stabilizing the spine.