Adolescent idiopathic scoliosis (AIS) involves three-dimensional spinal deformity in children aged between 10 and 16. Traditional braces modify the natural dynamics and thus the mechanical behaviour of the scoliotic spine through external constraints. Patients usually develop pressure ulcers and skin irritation when prescribed brace treatment for 18-23 hours per day. The excessive pressure, unknown pressure distribution and pressure shifting between the human body and the brace causes the effects of brace treatment to be unpredictable. Dynamic pressure monitoring system will be developed based on the body landmarks of scoliotic patients and critical areas where active pressure is applied by the brace. The overall pressure distribution and dynamic pressure between the body and the thoraco-lumbo-sacral orthosis (TLSO) rigid brace will be measured. The efficacy of the brace design will be evaluated, and the maximum compressive stresses that patients can endure on different body parts without pressure injury can be computed.

Global rates of adolescent idiopathic scoliosis (AIS) range from 0.9% to 12%, and within this population, approximately 10% of adolescents aged 10-16 will eventually need treatment. The most common conservative treatment is bracing, in which AIS patients are prescribed a brace for 18 to 23 hours daily until skeletally mature. The objective of bracing is to stop curve progression and restore normal alignment of the spine by active pressure from the brace. There is strong clinical evidence of a positive correlation between the tightness of daily brace application and the ability of the brace to decrease the risk of curve progression to a surgical threshold. However, patients suffer physical and functional discomfort resulting from pressure points, including pressure ulcers, skin irritation and even asthma attacks, which reduces compliance with brace treatment. Clearly, the knowledge of human body responses to pressure applied by brace treatment remains lacking.

This multi-disciplinary collaborative study involves experts in electrical and electronic engineering, orthopaedics, materials science and textiles, and biomechanics. A revolutionary pressure measurement system that integrates fibre optic sensors with textile yarns will be developed in the form of an undergarment. The sensor arrangement in the undergarment will be designed according to the body landmarks of scoliotic patients and critical areas where active pressure is applied by the brace. The overall pressure distribution and dynamic pressure between the body and the scoliosis brace will be measured. The efficacy of the brace design will be evaluated, and the maximum compressive stresses that patients can endure on different body parts without pressure injury can be computed.

Academia, clinicians and AIS patients are predicted to benefit from using the pressure system, which determines the optimum pressure to be exerted on patients while minimizing pressure injuries. The output of the project can be extended to the standardization of pressure levels applied by different orthotic devices and will add a new dimension to fibre optic applications in biomechanics.

Inclusion Criteria:

• Teenagers diagnosed with adolescent idiopathic scoliosis
• Cobb's angle between 25 to 45 degrees
• Immature skeletons (Risser grade 0-2)
• Types of scoliosis are classified by the Lenke classification system
• Have received rigid brace treatment

Exclusion Criteria:

• Contraindications for x-ray exposure
• Diagnosis of other musculoskeletal or developmental illness that might be responsible for the spinal curvature
• History of previous surgical treatment for AIS
• Contraindications for pulmonary and/ or exercise tests
• Psychiatric disorders
• Recent trauma
• Recent traumatic (emotional) event

The study will be divided into two phases. In Phase 1, an exploratory pilot study will be performed with up to two different braces tried on the same patient in one spinal centre in Hong Kong.