Spinal Conditions: Spinal Deformity
What is Spinal Deformity
Spinal deformity is a condition that occurs when the natural curvature of the spine is altered or abnormal. The normal spine has a cervical lordosis, thoracic kyphosis and lumbar lordosis. These are seen when looking at the spine from the side. The normal spine is usually straight when looked at from the front or from behind. A scoliosis is a curvature of the spine when looked at from the front or from behind. It is often S-shaped. A kyphotic deformity (or kyphosis) is when there is an excessive forward curvature of the spine when looked at from the side (beyond that of the normal curvatures of the spine).
A structural deformity is one in which there has been a true physical change in the shape of the spine. Structural deformities can be fixed (does not correct) and flexible (does correct). A physiological deformity is one in which there appears to be a deformity of the spine, but it is often caused by pain rather than a true change in the shape of the spine (an example of this is acute muscular back spasm). Physiological deformity usually improves.
Spinal deformity can present in several different ways. These include: abnormal curvature of the spine, a visibly rounded upper back, a hump on the back, uneven shoulders or hips, one shoulder blade that sticks out more than the other, one side of the rib cage appears higher than the other, pain or discomfort in the back or neck, reduced mobility or range of motion in the back, fatigue or weakness in the back, and rarely difficulty breathing or chest pain (only in severe cases).
The diagnosis of a spinal deformity is usually made following a clinical examination along with radiological imaging such as X-Ray. The management will depend on the cause of the deformity, but in general there is observation and monitoring, physical therapy and exercise, bracing and finally surgical correction. Early diagnosis and management are key as this can help to prevent progression of the deformity and improve overall quality of life.
As with other spinal conditions, it is important that patients with spinal deformity maintain good posture (including the use ergonomic equipment, such as an adjustable chair and keyboard whilst at work), practice safe lifting techniques, eat a healthy diet, and stay active and exercise regularly to maintain good overall health and fitness.
Scoliosis
There are several different causes of scoliosis.
Congenital Scoliosis occurs because of a spinal abnormality that develops before birth. The condition can vary in severity and may be associated with other birth defects or abnormalities. Congenital scoliosis is relatively rare, affecting around 1 in 10,000 live births. The spinal abnormalities causing this type of scoliosis are often detected on prenatal ultrasound scans.
Early Onset Scoliosis is a type of scoliosis that develops in children under the age of 10. The condition can be caused by a variety of factors, such as congenital spine abnormalities, neuromuscular disorders, or skeletal dysplasias.
Adolescent Idiopathic Scoliosis is the most common type of scoliosis, accounting for approximately 80% of all scoliosis cases and it develops in children between the ages of 10 and 18 years. The term "idiopathic" means that the cause of the scoliosis is unknown. The majority of adolescent idiopathic curves are right sided.
Neuromuscular Scoliosis is a type of scoliosis that occurs because of a neuromuscular disorder, such as cerebral palsy, muscular dystrophy, or spinal muscular atrophy. The underlying neuromuscular condition often causes muscle weakness, paralysis, or spasticity, leading to an abnormal curvature of the spine.
Syndromic Scoliosis is a type of scoliosis that occurs because of an underlying genetic or chromosomal disorder, such as Marfan syndrome, Down syndrome, or neurofibromatosis. The condition can cause a range of symptoms, including abnormalities of the bones, connective tissues, and nervous system.
Traumatic Scoliosis is a type of scoliosis that occurs because of spinal injuries, such as fractures or dislocations. The trauma can cause the spine to shift out of alignment, leading to a curvature of the spine. Alternatively, the deformity can occur because of neuromuscular imbalance following the spinal cord injury.
Tumour associated Scoliosis is a very rare form of scoliosis because of an underlying tumour affecting the shape of the spine.
Further Investigations
Scoliosis is usually diagnosed following a clinical examination and an X-Ray of the spine. When investigating the underlying cause of a scoliosis, further investigations such as MRI and CT scan are often performed to investigate any underlying cause. Preoperatively, bending X-Rays can be performed to assess the flexibility of the scoliosis to help determine the number of spinal levels that require instrumentation. Occasionally, CT SPECT and Bone scans are performed.
Several measurements can be taken from X-Rays. The most important of these is the Cobb angle. This is a measure of the size of the curvature.
Management of Scoliosis
The general goals of management in scoliosis are to prevent progression of the deformity, prevent long term cardiopulmonary complications (generally very rare), prevent chronic pain, and prevent decreased self-image. Additional goals (especially in those with congenital, neuromuscular and syndromic scoliosis) include optimising functional ability, improving sitting position, reducing any pressure area issues, reducing any costopelvic impingement, and reducing trunk fatigue.
Conservative management includes observation and monitoring, physical therapy and exercise, and bracing. In certain patients (for example those with congenital, neuromuscular and syndromic scoliosis) wheelchair modifications and sleep systems are utilised. Others might require specialist orthotics input (for example foot and ankle orthoses to address limb length discrepancies that result in pelvic obliquity and scoliosis).
The indications for surgery in scoliosis depend on the underlying cause and the patients’ individual circumstances. In adolescent idiopathic scoliosis surgery can be indicated to prevent progression of deformity in curves >40 degrees in immature patients and >50 degrees in mature patients or in rapidly progressive curves.
The goals of scoliosis surgery are to correct the deformity, prevent curve progression, obtain solid fusion (in fusion cases), prevent any long term pain, balance the spine above a level pelvis, correct any pelvic obliquity, prevent progressive respiratory and or cardiac compromise due to the deformity, optimise functional ability, improve sitting position and reduce any pressure area issues, reduce any costopelvic impingement, reduce trunk fatigue and improve cosmetic appearance.
In the growing spine surgeons try to avoid fusion surgery as this prevents growth. Serial bracing, plaster casts and growing rod constructs can be used to help modulate the progression of deformity whilst permitting growth of the patient. More recently vertebral body tethering has been introduced to modulate and correct the progression of minor to moderate flexible scoliotic curvatures in children that are still growing (usually curves 30 to 65 degrees).
Kyphosis
There are several different causes of kyphosis. These include Scheuermann’s, postural, congenital, neuromuscular, idiopathic, degenerative, osteoporotic and traumatic. The diagnosis, investigation and management are very similar to that of scoliosis.
Scheuermann's Kyphosis
The exact cause of this type of kyphosis is unknown. Type I affects the thoracic spine only and type II affects the lower thoracic spine and lumbar spine. Patients often presents with pain as well as deformity. The normal thoracic kyphosis measures 25-40 degrees and normal thoracolumbar kyphosis is 0 degrees. In Scheuermann’s kyphosis the thoracic spine kyphosis needs to be >40 degrees or thoracolumbar spine kyphosis >30 degrees and at least 3 adjacent vertebrae demonstrating wedging of >5 degrees. Other signs of the condition include: vertebral endplate irregularity due to extensive disk invagination and intervertebral disc space narrowing, more pronounced anteriorly. The main differential diagnosis is postural round back. The management depends on the degree of kyphosis and the age of the patient. Curves <50 degrees are often managed conservatively with stretching, maintaining good posture, and participating in regular physical activity. Curves of 50-75 degrees can be considered for brace treatment and curves >75 degrees can be considered for surgical intervention.
Adult Spinal Deformity
Adult spinal deformity refers to an abnormal curvature of the spine that develops in adulthood. Adult spinal deformity can occur because of aging, degenerative changes in the spine, or prior spinal surgeries. Currently, the most important concept in adult spinal deformity is sagittal balance (and not scoliosis). Sagittal balance refers to the ability to stand upright. Loss of sagittal balance can occur through a variety of mechanisms. Loss of lumbar lordosis from any cause is often the precipitant. In order to maintain an upright position, the body will tilt the pelvis backwards and extend the hips along with contraction of the posterior spinal muscles. This can result in reduction of the normal thoracic kyphosis. Further sagittal decompensation will result in increased cervical lordosis, to maintain horizontal gaze, and attempted increased extension of the lumbar spine (this can result in a retrolisthesis). Knee flexion and ankle extension can also occur. The stages of sagittal imbalance move from a normal harmonious spine to a compensated sagittal imbalance though to decompensated sagittal imbalance in which the body can no longer maintain an upright posture.
The management of adult spinal deformity depends on the underlying cause and the patients’ individual circumstances. Surgical intervention for adult spinal deformity is high risk and can carry with it significant complications.