Scoliosis is defined by an abnormal sideways curvature of the spine, often with a rotational element, which typically manifests during the adolescent growth spurt. This deviation from the spine’s natural alignment causes a noticeable loss of vertical stature. Correcting the spinal curve often restores this lost height, as successful treatment results in a measurable increase in standing height.
How Scoliosis Causes Height Loss
The biomechanical consequence of a scoliotic curve is a reduction in the vertical length of the trunk. When the spine develops an “S” or “C” shape, its overall length is compressed, much like a straight piece of string curved into an arc. This lateral deviation means the vertebrae are no longer stacked directly, which shortens the torso’s height.
The severity of the curve, measured by the Cobb angle, directly relates to the amount of height loss experienced. As the curve progresses, it also introduces uneven pressure on the intervertebral discs, the cushions between the vertebrae. This uneven force can lead to compression and a reduction in disc thickness, further contributing to the loss of trunk height.
Height Restoration After Surgical Correction
Surgical correction of scoliosis, typically performed through spinal fusion, results in a gain of spinal height. While the procedure’s main goals are to stop curve progression and stabilize the spine, the straightening effect naturally lengthens the trunk. The height gained is the length that was previously lost due to the abnormal curvature.
Studies consistently show that patients experience a substantial height increase following surgical correction. The mean gain in spinal height immediately following surgery is often reported to be around 27.1 millimeters (about 1.1 inches). Clinical measurements of standing height can show an average gain of 3.1 to 4.2 centimeters, or up to 1.6 inches. Patients with severe curves (greater than 60 degrees) sometimes gain more, exceeding 4 centimeters (over 1.5 inches).
Factors Influencing the Amount of Height Gain
The magnitude of height restoration depends on several specific patient and surgical factors. The severity of the initial spinal curve is the strongest predictor, as a larger Cobb angle means a greater length of compressed spine is available to be straightened. For example, a one-degree correction in the thoracic Cobb angle may correspond to approximately a 0.2-millimeter height gain.
The flexibility of the scoliotic curve also plays a significant role; a more flexible curve allows for a greater degree of straightening during the operation, resulting in more height gain. Conversely, a rigid curve resists full correction, limiting the potential height increase. The number of vertebral levels included in the spinal fusion is another predictor, as fusing more segments allows for more leverage to correct the curve and increase the spinal length.