Halo-Gravity Traction (HGT) is a specialized, non-operative technique used to manage severe spinal deformities, particularly rigid scoliosis, before definitive surgery. Scoliosis is characterized by an abnormal, sideways curvature of the spine. HGT involves attaching a metal ring, or “halo,” to the skull and using a weighted pulley system to apply a gradual, sustained stretch to the spine. This preparatory treatment is typically reserved for patients with high-magnitude curves, often exceeding 80 degrees, where immediate surgical correction would be unsafe.
Why Halo-Gravity Traction is Used
The primary rationale for using HGT is to safely increase the spine’s flexibility and length before a major corrective operation. Severe, rigid curves, especially those with a Cobb angle greater than 80 degrees, cannot be safely straightened all at once during a single surgery, as applying too much force risks neurological injury. HGT relies on the viscoelastic property of the spine, allowing its tissues to stretch and lengthen slowly over an extended period.
The slow, continuous pull utilizes gravity and gradually increasing weight to decompress the spinal column, effectively loosening stiff ligaments and soft tissue contractures around the curve. This preparatory lengthening significantly reduces the amount of correction needed during the subsequent surgery, lowering the risk of complications. Furthermore, the gradual straightening of the spine and torso can improve pulmonary function by allowing the rib cage and lungs to expand more fully.
How the Halo System is Applied
The process begins in a sterile environment, typically an operating room, where the halo ring is secured to the patient’s skull while they are under general anesthesia. The lightweight metal ring is attached using a series of small, specialized pins, often between six and twelve, which are inserted into the outer layer of the bone. The number of pins used often depends on the patient’s size.
Once the halo is securely in place, it is connected to a weighted pulley system, with the traction weight applied in a controlled, incremental manner. The initial weight is small and is gradually increased over days or weeks while the patient remains hospitalized. Typically, the weight is increased daily until the total traction weight reaches approximately 30% to 50% of the patient’s body weight. This slow, controlled increase ensures the spine is stretched gently, allowing the body to adapt without undue strain. Throughout this period, the medical team monitors the patient’s neurological status and takes regular X-rays to track the spinal correction and adjust the weight as needed.
Daily Life and Care During Traction
Patients undergoing HGT remain hospitalized for the entire duration of the treatment, which typically lasts three to twelve weeks. The daily routine centers on meticulous pin site care, performed by nurses and parents to prevent infection. This involves cleaning the skin around the pin entry points and monitoring for signs of redness or irritation. While the halo cannot be removed, patients are able to take short breaks from the weighted traction for activities like showering or changing clothes.
Despite the halo and pulley system, patients are encouraged to be as mobile as possible, using a specialized walker or wheelchair that incorporates the traction system. Physical and occupational therapists work closely with the patient to help them maintain muscle strength and adapt to performing daily tasks like eating and hygiene. The care team provides emotional support and activities to help the patient cope with the extended stay. Most patients experience a temporary headache or discomfort around the pin sites for the first day or two, but many report feeling more comfortable and having an easier time breathing once the spine begins to stretch.
The Purpose and Outcome of Halo Treatment
Halo-Gravity Traction is not a permanent treatment for scoliosis but rather a preparatory step to maximize the safety and effectiveness of the eventual surgery. The primary goal is to achieve the greatest possible spinal flexibility and partial curve correction before the final operation. This preoperative stretching often results in a significant reduction of the Cobb angle.
By lengthening the spine and loosening the stiff tissues, the procedure makes the definitive correction surgery, typically a spinal fusion, less complex and more successful. The partial correction achieved through HGT substantially reduces the risk of neurological complications during the fusion procedure. Once maximum safe stretch has been achieved, the halo is removed, and the patient proceeds to the final corrective surgery, which permanently stabilizes the spine in its new, straighter alignment.