Scoliosis is an abnormal, sideways curvature of the spine, often presenting as an S- or C-shape. While this deformity ranges from mild to severe and usually causes no significant health complications, a pronounced curvature, particularly in the mid-back region, can impair breathing. A severe curve can physically distort the chest cavity, which then restricts the space available for the lungs to fully expand. This restriction can lead to breathing difficulties and reduced lung capacity over time.
When Scoliosis Impacts Breathing
Breathing issues rarely occur in individuals with mild or moderate scoliosis. The risk of respiratory impairment becomes a concern when the curvature is substantial and located specifically in the thoracic spine, or mid-back. This section of the spine is directly connected to the rib cage, making it the most likely area to affect lung function.
The severity of the curve is measured by the Cobb angle on an X-ray. Experts generally consider a Cobb angle greater than 70 degrees as the point where a high risk of reduced lung volume and breathing difficulty begins. Curves between 30 and 70 degrees may cause some mild restriction, often only noticeable during strenuous activity.
How Spinal Curvature Restricts Lung Capacity
The development of breathing problems is fundamentally a mechanical issue caused by the three-dimensional nature of the spinal deformity. Scoliosis involves not only a lateral curve but also a rotation of the vertebrae, which dramatically twists and deforms the rib cage. This twisting leads to the characteristic “rib hump,” where ribs on one side are pushed out and ribs on the other side are compressed.
This deformation of the rib cage physically limits the size of the chest cavity, preventing the lungs from fully inflating, a condition known as restrictive lung disease. The restricted chest wall movement also places the respiratory muscles, including the diaphragm, at a mechanical disadvantage, forcing them to work harder. The resulting decrease in lung volume leads to symptoms like shortness of breath and reduced exercise tolerance.
Assessing Respiratory Function
Physicians use specialized clinical tools to evaluate the extent of breathing impairment caused by scoliosis. Pulmonary Function Tests (PFTs) are the standard method for measuring how well the lungs are working. These tests measure different lung volumes to identify a restrictive ventilatory defect, which is characteristic of scoliosis-related lung problems.
Key measurements include Forced Vital Capacity (FVC) and Total Lung Capacity (TLC), which quantify the maximum amount of air a person can exhale and the total volume of air the lungs can hold, respectively. A proportional reduction in both FVC and TLC indicates a restrictive pattern, meaning the lungs cannot expand fully. The Cobb angle measurement from X-rays serves as a primary predictor, as a larger angle correlates strongly with a higher likelihood of diminished thoracic volume and reduced lung function.
Interventions for Breathing Difficulties
Treatment strategies for scoliosis-related breathing issues focus on improving or preserving the space available for lung function. For moderate curves, bracing is often used to prevent the curve from progressing further, thereby protecting the lungs from increased restriction. When the curve is severe and respiratory function is compromised, more aggressive interventions may be necessary.
Surgical correction, typically spinal fusion, aims to straighten the spine and de-rotate the rib cage, which can help increase the thoracic volume and improve lung capacity.
Non-surgical approaches include aggressive physical therapy, such as the Schroth method. This method uses specific rotational breathing exercises to expand the compressed areas of the rib cage and improve chest wall mobility. These targeted exercises teach patients to breathe into the concave, or sunken, side of the torso, helping to maximize the available lung space and strengthen respiratory muscles.