IPH REHAB : BIOMECHANICS OF SPINAL ORTHOSIS

IPHREHAB

Biomechanics of the spine orthosis

• The cervical spine is the most mobile spinal segment with flexion greater than extension. 
• The occiput and C1 have significant flexion and extension with limited side bending and rotation.
•  The C1-C2 complex accounts for 50% of rotation in the cervical spine.
•  The C5-C6 region has the greatest amount of flexion and extension. 
• The C2-C4 region has the most side bending and rotation. 

BIOMECHANICS

• When compared to the cervical and lumbar spine, the thoracic spine is the least mobile. 
• The thoracic spine has greater flexion than extension. 
• Lateral bending increases in a caudal direction, and axial rotation decreases in a caudal direction. 
• The lumbar spine has minimal axial rotation. The greatest movement in the lumbar spine is flexion and extension.

The biomechanical principles in orthotic design include: 

1. Balance of horizontal forces
2. Fluid compression, distraction
3. Construction of a cage around the patient
4. Placement of an irritant to serve as a kinesthetic reminder 
5. Skeletal fixation. 

Biomechanics of the spine orthosis

• Construction of a cage around the patient, like a thoraco-lumbar brace, increases intraabdominal pressure.
•  Increased intra-abdominal pressure converts the soft abdomen into a semirigid cylinder, which helps to relieve part of the vertebral load 

Orthosis can be divided as:-

• Cervical orthosis
• Head cervical orthosis
• Thoraco-lumbar orthosis
• Lumbo-sacral orthosis
• Orthosis for deformity (scoliosis)

Success of the orthosis may lead to:-

• Decreased pain 
• Increased strength 
• Improved function and posture  
• Correction of spinal curve deformity 
• Protection against spinal instability 
• Minimized complications 
• Healing of ligaments and bones