Adolescent Idiopathic Scoliosis and What GPs Should Know

PRESENTATION OF AIS

Patients with AIS often have no symptoms. Some, however, may complain of mild back pain or discomfort that does not usually affect their daily activities.

Others may seek medical advice after family members or friends, or even they themselves, have noticed an asymmetrical slant to their trunk or uneven shoulders or waist.

However, it is not unusual for patients with scoliosis to present ‘late’ – ‘late’ being defined as scoliosis with a Cobb angle of 40 degrees or more. 

A study performed on our local population⁴ identified the top three reasons for the delay in seeking tertiary evaluation as:

1. Not thinking the scoliosis was a problem

2. Being too busy

3. Simply not realising they had scoliosis

Red flags

While the majority of adolescents presenting with scoliosis are otherwise healthy with no significant medical conditions, it is essential that they are screened for red flags which may point to a more sinister underlying pathology.

These red flags include:

• The presence of back pain that is well-localised and constant

• Back pain that is progressively worsening

• Weakness or clumsiness in the upper and lower limbs

• The presence of bladder or bowel dysfunction 
  

History taking

In addition, asking about the onset of the menarche or voice break, as well as when the child or parents noted a growth spurt, if any, can be an indication of the skeletal maturity of the child. This has a huge impact on the prognosis of scoliosis and its subsequent management.

Finally, key points in the history may point to nonidiopathic causes of scoliosis:

• Birth history: a difficult or prolonged labour may be associated with cerebral palsy and neuromuscular scoliosis

• Developmental milestones: a developmental delay may indicate a non-idiopathic cause of scoliosis

• Family history of spinal disorders
  

How GPs Can Screen For Scoliosis

Besides excluding red flags in the history, scoliosis can be picked up in the outpatient setting by: 

• Looking for waist or shoulder asymmetry when the patient is adequately exposed (Figure 1A) 

• Inspecting the trunk and limbs for café-au-lait spots and axillary freckling – seen in neurofibromatosis, which is associated with scoliosis

• Inspecting the back for sacral dimpling or a hairy patch – often seen in spinal dysraphism (congenital defects in the spinal cord and vertebrae)

• Performing a simple screening test: the Adam’s FBT
  This involves asking the patient to bend forward at the waist as if to touch their toes, with the elbows and knees extended and palms opposed. (Figure 1B) The GP now stands at eye level with the patient’s back and looks for one side being higher than the other. Using a scoliometer can quantify the degree of rotation in the axial plane. There are also scoliometer apps available online which may be more convenient.

• Examining the patient’s gait and posture, in particular looking for a short-limb gait which may indicate a limb length discrepancy In addition, performing a detailed neurological examination testing the motor power, sensory function and reflexes is essential. Asymmetry noted in the reflexes may be an indication of an intraspinal disorder.
  

When to refer to a specialist

Should there be any positive findings, a referral to the paediatric orthopaedic spine surgeon can be made for further investigations (EOS radiographs and advanced imaging such as MRI, if indicated) and management.

DIAGNOSIS AND MONITORING OF AIS

Full-length standing radiographs

Full-length standing radiographs taken in both the posteroanterior and lateral profiles are essential in order to accurately diagnose and assess the degree of the deformity by measuring the Cobb angle. 

In addition, radiographs allow gauging of the skeletal maturity of the child using either the Risser scoring or the Sanders Maturity Scale.

Isolated views of the thoracic or lumbar spine alone do not suffice in diagnosing scoliosis as they may under- or over-exaggerate the actual deformity. 

EOS connect imaging system

The EOS connect imaging system (Figures 2 and 3) is a service now available at most tertiary hospitals. 

It produces a high-quality image with 50% less radiation as compared to a digital radiograph utilising a conventional X-ray system.

This allows safer care for our paediatric patients who require multiple radiographs during the course of their treatment.

MRI or CT scans

MRI or CT scans of the spine are sometimes performed if indicated, such as when there are neurological deficits or atypical scoliotic curves detected on plain radiographs.

Adapted from Altaf F, Gibson A, Dannawi Z, Noordeen H. Adolescent idiopathic scoliosis BMJ 2013; 346 :f2508

Providing comprehensive care for paediatric patients with scoliosis requires a team-based approach involving the GP, orthopaedic spine surgeon, allied health professionals, prosthetists and orthotists.

Regular assessment and exercises

Patients with mild curves (less than 20 degrees) are observed with regular assessments every four to six months. Physiotherapeutic scoliosis-specific exercises (PSSE) may also be commenced for three-dimensional self-correction, core strengthening and stabilisation of the corrected posture.

Bracing

The primary goal of bracing is to halt curve progression. A brace is usually offered for curves between 20 to 40 degrees in patients who are rapidly growing (Risser stages 0-2).

Patients are recommended to wear the brace for at least 18 hours a day and are encouraged to continue all sporting activities during the bracing period.

Poor compliance is an obstacle to successful brace treatment and the presence of a strong support system that includes the patient’s family, GP, orthopaedic surgeon, orthotist and physiotherapist can help reinforce the importance of bracing to the child.

Bracing is discontinued when the child has reached skeletal maturity or when the magnitude of the curve has exceeded the surgical threshold.

Surgery

It is estimated that about 10% of adolescents with idiopathic scoliosis will eventually require surgical intervention.⁵

Surgery is considered in skeletally immature patients with curves exceeding 45 degrees and skeletally mature patients with curves exceeding 0 degrees, as the curves in these two scenarios are expected to progress even after maturity, which may lead to an increased risk of low back pain, worsening physical deformity and reduced lung function in some cases.

The aims of surgery are to:

• Correct the deformity,

• Halt progression by achieving a solid fusion construct, and

• Achieve a spine that is balanced in both the coronal and sagittal planes

The gold standard to halt curve progression while providing curve correction remains posterior spinal fusion (PSF) with pedicle screw fixation. There is an increasing use of intraoperative navigation to guide pedicle screw placement. This includes the 7D Machine-vision Image Guided Surgery (MvIGS) system, which has been shown to allow significant reduction in intraoperative radiation exposure, fluoroscopy time, as well as blood loss and length of stay.⁶

This has allowed both:

• Further reduction in the already very low incidence of nerve and spinal cord injuries

• Enhanced patient safety by minimising X-ray use during the surgery
  

Dr Stacy Ng completed her specialist training in 2021 and was elected Fellow of the Royal College of Surgeons (Ortho). She has a sub-specialty interest in conditions affecting the paediatric spine, including scoliosis. She has recently completed her surgical fellowship in complex paediatric spinal deformities at Centre des Massues in Lyon, France. GPs who would like more information on this topic, please contact Dr Ng at [email protected].

GPs can call the SingHealth Duke-NUS Spine Centre for appointments at the following hotlines or click here to visit the website:
Singapore General Hospital: 6326 6060
Changi General Hospital: 6788 3003
Sengkang General Hospital: 6930 6000
KK Women's and Children's Hospital: 6692 2984
National Neuroscience Institute: 6330 6363