Introduction
Scoliosis is the lateral curvature of the spine with associated rotation of the vertebrae within the curve. A lateral curvature, defined by a Cobb angle of at least 10 degrees, is required for the diagnosis to be made (any lesser deformity is defined as spinal asymmetry).
Scoliosis is present in 0.2-6% of the population and is more common in females. The majority of scolioses (70%) are idiopathic, the majority being adolescent idiopathic scoliosis (occurring between 10 -16 years), whilst those with an underlying cause may be due to:
- Congenital, whereby a primary vertebral body abnormality present at birth
- Neuromuscular, such as cerebral palsy, Duchenne muscular dystrophy, or traumatic paralysis
- Syndromic, such as connective tissue diseases, Down syndrome, or neurofibromatosis
- Secondary, such as chronic pain, spinal cord abnormalities, adjacent tumours, or infection
Cobb Angle
The Cobb Angle is used to describe the severity of the lateral curvature in cases of scoliosis, whereby an angle >10° is needed for a diagnosis.
A line is drawn along the endplates of the two terminal vertebrae (those which are most tilted towards one another) and the angle at which these lines intersect is calculated.
Figure 2 – Schematic demonstrating the Cobb angle (here showing an angle of 89 degrees)
Risk Factors
The majority of scolioses are idiopathic in nature. However, its development may be associated with a positive family history, female gender, previous injury to the spine, chronic back pain, developmental delay, or involvement in high-risk sports (such as gymnastics) from an early age
Risk factors for progression of scoliosis include family history, osteopenia or osteoporosis, or a larger initial Cobb angle.
Clinical Features
Scoliosis will typically be suspected from a patient’s posture, especially in the case of more significant curves. The patient may have shoulder asymmetry or a sideways body posture.
Symptoms can be varied between patients, the majority presenting with chronic back pain or psychosocial distress, but may present with cardiopulmonary compromise in severe disease.
Although diagnosis is mainly radiological, screening examination can be performed using the Adam’s forward bend test (Fig. 3)
Figure 3 – Schematic demonstrating the Adam’s forward bend test
Differential Diagnosis
Differential diagnoses that present in a similar way to scoliosis include postural asymmetry, functional scoliosis (e.g. due to leg length discrepancies or muscle spasms), Scheuermann’s disease (also termed juvenile kyphosis), and spondylolisthesis
Investigations
Diagnosis and monitoring of scoliosis is mainly achieved through plain film radiographs, which can to properly categorise and assess the curve . Concurrent concurrent pathologies, such as hemivertebrae, fractures, and other structural abnormalities, can also be assessed for.
The rigidity of a curve can further be assessed on plain film radiography using lateral flexion views, where the patient is asked to bend their upper body maximally to the left and the right*.
MR and CT imaging may be indicated when an underlying osseous or neurogenic cause is suspected, such as syringomyelia, pars defects, or facet joint degeneration.
*If a curve cannot be straightened to <25° then it is considered structural, otherwise it is termed a “non-structural compensatory curve”
Figure 4 – A plain film radiograph showing severe scoliosis
Management
Whilst management of scoliosis will vary, as a general rule, mild curvatures can be monitored with watchful waiting initially, and non-operative management can be offered to those patients with worsening angles (e.g. >25 degrees).
Surgical management becomes indicated when there is ongoing pain in those unresponsive to conservative treatments, worsening symptoms and functional capabilities, or a curve progressing beyond a pre-defined threshold (e.g. > 45 degrees). In children <10yrs, treatment is more focused to preventing the development of thoracic insufficiency syndrome
Non-operative treatment mainly involves either physiotherapy and bracing:
- Physiotherapy aims to maintain muscular endurance and strength, range of motion, coordination and other factors to help prevent curve progression and enhance the effectiveness of bracing
- Bracing acts to limit curve progression and its effectiveness is often proportional to the time spent wearing it (is typically performed for >16 hours per day, Fig. 5); its main issues are around patient compliance, which often limits its effectiveness
- Bracing is especially useful before the patient reaches skeletal maturity
Figure 5 – A female patient in a Boston brace for scoliosis
Surgical Management
Operative treatment aims to prevent curve progression, achieve maximum permanent correction of the deformity (in all dimensions), and improve overall appearance (by balancing the trunk)
The specific surgical management of scoliosis is complex, however the mainstay of scoliosis procedures is with spinal fusion surgery (Fig. 6). This surgery often requires posterior or anterior spinal fusion and stabilisation, vertebral body tethering, osteotomy, and anterior release of intervertebral discs and ligaments.
Modern techniques include the use of growing rods, which can be lengthened to accommodate a patient’s growth as they age.
Complications following surgery include surgical site infection, neurological deficits, pseudoarthrosis, and proximal and distal junctional kyphosis.
Figure 6 – Pre-operative and post-operative plain film radiographs, following ventral fusion surgery for scoliosis
Complications
Consequences of untreated scoliosis include curve progression, pulmonary disease (more significant in early-onset scoliosis, where thoracic insufficiency syndrome may develop), chronic back pain, and psychosocial distress, as well as increase the risk of degenerative disc disease.
Key Points
- Scoliosis is the lateral curvature of the spine with associated rotation of the vertebrae within the curve
- The majority of scolioses are idiopathic in nature
- Diagnosis and monitoring of scoliosis is mainly achieved through plain film radiographs
- Most cases can be managed through active monitoring or non-operative management, however select cases may eventually require surgical intervention
Figure 1 - A young male patient with severe scoliosis[/caption]
Figure 2 - Schematic demonstrating the Cobb angle (here showing an angle of 89 degrees)[/caption]
Figure 3 - Schematic demonstrating the Adam’s forward bend test[/caption]
Figure 6 - Pre-operative and post-operative plain film radiographs, following ventral fusion surgery for scoliosis[/caption]