Adult spinal deformity (ASD) is a condition involving an abnormal alignment or curvature of the spine in an adult, which can result from age-related changes or the progression of a condition from childhood. The spine has natural curves that support the body’s weight and maintain balance. When these curves become misshapen or their alignment shifts, it can lead to physical challenges. This condition is diagnosed with increasing frequency in older populations as people live longer and more active lives.
Types of Spinal Deformities in Adults
The spine is designed with specific curves when viewed from the side, but it should appear straight when viewed from the back. Spinal deformities are classified based on the direction of the abnormal curve.
One of the most widely recognized types is scoliosis, which is characterized by a side-to-side curvature of the spine. A curve greater than 10 degrees is defined as scoliosis, and this condition can affect the upper, middle, or lower sections of the back.
Another primary type is kyphosis, which involves an excessive forward rounding of the spine, most often in the upper back. This creates a “hunchback” appearance. In contrast, an excessive inward curve in the lower back is known as lordosis. Both conditions relate to the spine’s front-to-back alignment, and when this is off, it is referred to as sagittal imbalance, making it difficult to stand upright.
Underlying Causes and Development
The development of adult spinal deformity is often due to the natural aging process. Over time, intervertebral discs, which cushion the vertebrae, can lose hydration and flexibility. This disc degeneration leads to a loss of height in the disc space and can cause the spine to shift out of alignment. Arthritis in the facet joints and the weakening of spinal ligaments also contribute to instability and progressive deformity. Osteoporosis, a condition causing bones to become brittle, can lead to vertebral compression fractures that alter the spine’s shape.
Some cases of adult spinal deformity are a continuation of a condition from adolescence. Adult idiopathic scoliosis, for instance, is when scoliosis present during teenage years progresses in adulthood. Another cause is iatrogenic deformity, which can occur as an unintended consequence of previous spinal surgery, such as a laminectomy. Less commonly, deformities can arise from traumatic injuries or underlying neuromuscular conditions.
Associated Symptoms and Health Impacts
One of the most common complaints with adult spinal deformity is chronic back pain. This pain can be localized to the area of the deformity or may spread more widely due to the body’s efforts to compensate for the imbalance. Muscle fatigue is also frequent, as the body works harder to maintain an upright posture.
Visible changes in posture are another hallmark, which can manifest as a sideways lean, uneven shoulders, or a prominent hump on the back. As the spine’s curvature progresses, a person may experience a loss of height. These postural shifts can affect balance, making activities like walking or standing for prolonged periods difficult.
In some cases, the altered spinal alignment can compress nerves or the spinal cord. This nerve compression, known as radiculopathy, can cause pain, numbness, or weakness in the legs or arms. In severe instances of kyphosis, the forward curvature can reduce space in the chest cavity, potentially affecting breathing and digestion.
The Diagnostic Evaluation
Diagnosing an adult spinal deformity involves a physical assessment and detailed imaging. A healthcare provider will take a medical history and perform a physical examination to assess posture, range of motion, and overall spinal alignment. The provider will observe the patient standing and walking to check for visible signs of imbalance, such as a stooped posture.
Full-spine X-rays are used to get a comprehensive picture of the bone anatomy and the alignment of the entire vertebral column. These images allow doctors to measure the precise angles of any abnormal curves, using a measurement known as the Cobb angle for scoliosis. X-rays also help evaluate overall spine balance by looking at the sagittal vertical axis (SVA).
To get a more detailed view, an MRI scan can visualize soft tissues like the spinal cord and nerves to check for compression. A CT scan provides a more detailed look at the bones and can be helpful in assessing bone quality or identifying fractures.
Management and Treatment Strategies
The management of adult spinal deformity begins with non-operative treatments to alleviate pain, improve function, and slow the deformity’s progression. Physical therapy is a central element of this care. A therapist can design a program focused on strengthening the core muscles that support the spine, improving flexibility, and training for better posture.
Pain management is another aspect of conservative treatment and can include medications to reduce inflammation and relieve discomfort. In some cases, targeted epidural steroid injections may be used to deliver medication directly to the source of pain. For some patients, a brace may be recommended to provide external support for the spine.
When conservative treatments do not provide sufficient relief, or if the deformity is progressing and causing neurological symptoms, surgery may be considered. The goals are to decompress nerves, stabilize the spine, and correct the alignment. This often involves procedures to fuse portions of the spine into a solid, stable position using bone grafts and instrumentation like rods and screws.