Multilevel Contiguous Osteoporotic Lumbar Compression Fractures: The Relationship of Scoliosis to the Development of Cascading Fractures.

Osteoporotic patients can present with either single or multiple fractures secondary to repeated falls and progressive osteoporosis. Multiple fractures often lead to additional spinal deformity and are a sign of more severe osteoporosis. In the thoracic spine, multiple fractures are associated with the development of gradual thoracic kyphosis but neurologic deficits are uncommon. In the lumbar spine, patients with multiple lumbar fractures have more constant lumbar pain, may have symptoms related to concurrent lumbar stenosis or degenerative scoliosis, and may present with radiculopathy, especially with fractures at L4 and L5. In a review of a series of patients with recurrent multiple lumbar fractures or 'cascading' fractures, it was found that all the patients were female, had severe osteoporosis, often untreated, had a previous history of multiple previous thoracic and lumbar fractures, and all had associated scoliotic spinal deformities ranging from 6o to 50o. It was found that if the curve progressed and the greater the degree of curvature, the more frequently subsequent multiple fractures developed, leading to recurrent acute episodes of pain. Forty percent also had additional sacral insufficiency fractures, an unusually high percentage. Biomechanically, the lumbar spine is both more mobile and supports a larger portion of the spinal load compared to the thoracic spine. The existence or worsening of a lumbar spinal deformity from degenerative lumbar scoliosis shifts the mechanical forces more to one side on already weakened osteoporotic lumbar vertebrae and sacrum, leading to an increased incidence of these fractures. Because of the chronic and uneven lower lumbar spinal load with severe vertebral osteoporosis in certain patients with repeat lumbar fractures and worsening degenerative lumbar scoliosis, there may be a rationale to add preventive vertebroplasty at adjacent vertebral endplates when treating acute recurrent lumbar fractures to decrease the incidence of recurrence in other vertebrae.