SOMI Brace

Sternal-Occipital-Mandibular Immobiliser (SOMI) Brace 

• Cervico-Thoracic Orthoses (CTOs) provide greater motion restriction from C5-C7 spine from the increased leverage on the person’s body.
• The upper cervical spine has less motion restriction.
• CTOs are used in minimally unstable fractures.
• All CTO’s tend to control flexion better than extension.

Parts

1. The SOMI is a rigid, 3-poster CTO that has an padded anterior chest plate extending to the xiphoid process, as well as two padded shoulder extension which hook over tops of the shoulder.
2. From these shoulder extension two Straps which cross in the interscapular region, pass downward and around the chest wall to attach to the lower part of the chest plate.
3. There are three adjustable uprights, which pass upward from the chest plate, two to the padded occipital support and one to the mandibular support.
4. A removable chin piece attaches to the chest plate with an optional headpiece that can be used when the chin piece is removed for eating.

• The SOMI is ideal for bedridden patients because it has no posterior rods.
• The SOMI is relatively comfortable to wear. Proper adjustment is crucial for motion restriction, which may be minimal if the orthosis is correctly applied.
• The SOMI controls extension less effectively than the other braces do, but it very effectively controls flexion at the atlantoaxial and C2-C3 segments.
• The SOMI controls flexion in the C1-C3 segments better than any other CTO brace. 

Motion Restrictions

• Cervical flexion and extension are limited by 70%-75%
• Lateral bending is limited by 35%
• Rotation is limited by 60-65%

Indications

• Atlantoaxial instability caused by rheumatoid arthritis (Note that ligamentous disruption in rheumatoid arthritis affects flexion more than extension, because extension is held in check by the intact dens).
• Neural arch fractures of C2, because flexion causes instability. 

Contraindications

• The SOMI controls extension less effectively than do other orthoses.
• Flexion and extension control at C3-T1: better served with a Minerva cast.