Thoracic Hyperkyphosis

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Hyperkyphosis, an excessive curvature of the thoracic spine, is a condition that primarily affects older adults. The standard measure for this condition is the Cobb angle, with a value of 50° or more in a standing position indicating hyperkyphosis. This condition is significant due to its potential role as a modifiable risk factor for various adverse health outcomes, including increased risk of falls, fractures, and possibly an indicator of underlying osteoporosis.

Pathogenesis

Kyphosis tends to increase with age. The Cobb angle is typically 20-29 degrees in younger adults, increasing to 35-38 degrees in adults aged 65 and older. Importantly not all older adults with thoracic hyperkyphosis have osteoporosis. Other factors can be at play.

Vertebral Fractures and Degenerative Disc Disease

Hyperkyphosis can result from anterior wedging of vertebrae and asymmetrical compression of intervertebral discs. Approximately 40% of individuals with hyperkyphosis have vertebral fractures, and each fracture can increase the kyphosis angle by an average of 3.8°. Age-related degenerative disc disease also contributes to hyperkyphosis, although the relationship between disc degeneration and hyperkyphosis is complex and may be mutually reinforcing.

Muscle Strength

Back extensor muscle strength inversely correlates with kyphosis. The strength of these muscles, or lack thereof, can influence the degree of curvature in the thoracic spine. However, the association between kyphosis and grip strength, another indicator of frailty, remains controversial with mixed results reported in various studies.

Genetic Predisposition

Genetic factors also play a role in hyperkyphosis. Studies indicate that hereditary diseases like Scheuermann's disease can lead to hyperkyphosis at an early age. Furthermore, studies suggest a significant heritability component to spinal curvature, with estimates ranging from 54% to 61%.

Adverse Health Effects

Physical Performance and Falls

Hyperkyphosis is associated with decreased physical performance and increased risk of falls in older adults. This association is attributed to a shift in the center of gravity and possible balance disruptions. However, the clinical relevance of this link is subject to debate due to small effect sizes and potential publication bias in the existing literature.

Fractures

There is a reported increase in vertebral fracture risk among individuals with hyperkyphosis. Studies indicate a higher incidence of vertebral fractures in women with hyperkyphosis, suggesting a potential mechanical effect of the increased curvature on the vertebrae.

Pulmonary Function

Limited studies suggest that hyperkyphosis may impair pulmonary function due to mechanical restriction, with affected individuals often showing decreased vital capacity and increased dyspnea. However, the extent to which hyperkyphosis contributes to respiratory diseases remains unclear.

Mortality

Several large cohort studies have linked hyperkyphosis with increased all-cause mortality in older adults, potentially reflecting the severity of underlying conditions such as osteoporosis.

Pain and Quality of Life

Hyperkyphosis has been associated with pain and a lower quality of life in older adults. This association is likely due to the combined effects of reduced physical performance, increased risk of falls and fractures, and potential respiratory complications.

Treatment

If osteoporosis is present then this should be addressed

There have been several small studies showing improvement in hyperkyphosis with extensor strength training or yoga. The SHEAF trial showed improvement in hyperkyphosis but no improvement in pain, this involved primarily postural training.

See Also

Sagittal Balance of the Spine

Resources

Thoracic Hyperkyphosis - Koele 2020.pdf - 1.6 MB (f)