SPINAL ORTHOSIS AND TRANSDUCERS USED IN PROSTHESIS AND ORTHOSIS

DEFINITION An appliance or apparatus used to support, align, prevent or correct deformities or to improve function of movable parts of the body. Spinal orthosis - external orthopedic appliance that prevents or assists movement of spine. Orthos means straight Types : Rigid or Semi-Rigid

HISTORY Dates back to Middle ages. Ambroise Pare – metal corsets in 16th century Lorenz Heister – 1st spinal orthosis in 17th century. Principles of immobilization have changed a little. Materials used, combination of surgery used & bracing has changed.

OBJECTIVES Controlling spinal position by external forces. Applying corrective forces to abnormal curvature. Providing spinal stabilization when soft tissues cannot. Restricting spinal segment movement after trauma.

Orthosis work through biomechanical effects of a 3 point force system on : Trunk and head support. Motion control. Spinal realignment. Partial weight transfer of the head to trunk when in upright position.

EFFECTIVENESS Points of application. Direction and magnitude of forces applied. Tightness of devices. Type of injury and instability produced. Body habits of the individual.

Types Neck braces Rigid braces Sacroiliac and lumbosacral belts Corset braces Hyperextension braces Molded jackets

NECK BRACES It is necessary to wear a neck brace if there is an injury to the neck Neck braces are among the most common of all spinal braces. Neck braces are also called collars. They can stabilize the neck after cervical spine surgery. They can provide non-surgical relief to the neck.

RIGID BRACES Rigid braces are used to treat low back pain. They are also commonly prescribed to stabilize the lumbar spine after surgery. They usually have metal or plastic uprights in the back that mirror the shape of the low back and pelvis. Rigid braces have bands that lay across the thoracic spine. To help transfer weight off the spine, these braces feature fabric straps that place pressure on the abdomen.

Sacroiliac Belts Sacroiliac belts are back braces. Help treat pain in the lumbar spine and sacrum.  A sacroiliac belt provides compression around the hip to prevent the SI joints from moving excessively. The belt is wrapped around the pelvis and may be tightened using laces on the side or back of the brace.

CORSETS Treat low back pain. degenerative disc disease trauma, fracture, or injury spinal deformity ( scoliosis) Made of nylon or cotton & is comfortable. Covers the area from the sternum down to the pelvic area & from shoulder down to buttocks. Works by increasing pressure in abdomen, reducing amount of weight placed on sensitive spinal structures & allows your spine to heal faster. May contain metal bars that provide rigid reinforcements to prevent movement and help improve posture.

HYPEREXTENSION BRACES Treat spinal compression fractures & recovers back from spine surgery Designed to limit movement in 2 regions of spine (thoracic spine & lumbar spine). To limit front bending,it features a rectangular metal frame that goes over the front of the body. Has 3 pads that help stabilize the spine & prevent forward movement. Prevents from bending forward. Prescribed if one just had spine surgery involving, thoracic or upper lumbar region of the spine.

MOULDED JACKETS (TLSO) It is a total-coverage brace. Provides rigid stabilization to spinal conditions, including spinal fractures & scoliosis. Is made of a hard, lightweight plastic shell with a soft inner lining . Controls movement in all directions & limits rotation. encourages healing by increasing pressure in abdomen and chest.

COMMON ISSUES Spinal stability. Pulmonary. Neurogenic bowel and bladder. Immobility: Skin breakdown. Spasticity. Bracing. Pain. Autonomic dysreflexia.

Transducers in prosthetics & orthotics Thick film sensors Temperature sensors Tilt sensors Pressure sensors Tactile sensors Myoelectrodes Electromechanical transducers LIT linear transducers

Thick film sensors Aim: Accommodate a variety of different hand postures. improve the functionality of prosthetic hands. Used to: Measure the grip forces exerted upon an object. Detect & react to the possible slip of a gripped item. Position: located upon stainless steel cantilever type structures that will be placed at the fingertips of each digit.

Temperature sensors Aim: Material discrimination. Extreme temperature avoidance. Psychological comfort. Used to: Provide temperature compensation for the force sensors Prevent accidental thermal damage to the prosthesis.

Tilt sensors Aim: Allows patient to use his own musculature to actively dorsi flex during swing. Provide : Stimulation to the peroneal nerve at late terminal stance through to initial contact Stimulation during normal gait.

SENSORS USED IN ORTHOSIS AND PROSTHESIS FIBER PRESSURE SENSOR : Used for sensors used to measure pressure around (POLYVAD) POLYVAD is temporary blood circulatory support pressure measurements in “Polish Artificial Heart” Pressure TACTILE SENSORS : Used for artificial skin prosthesis Tactile technique uses ‘Piezoresistivity’ Pressure sensitive ink between two conductive surfaces

TACTILE SENSOR

SENSORS USED IN AAA : (Abdominal Aorta Aneurisms ) Pressure sensors are used in this application Use to detect leakage Mainly “Capacitive Pressure Sensors” are used

Other Transducers MYOELECTRODES: Regulates speed and direction Speed is proportional to muscle signals TOUCH PADS: Pressure sensitive pads Operate by touch Fixed to socket

LTI LINEAR TRANSDUCER : Relative body motion into electric signals Position of prosthesis can be control Body motion translate into prosthetic motion ELECTROMECHANICAL TRANSDUCERS : Use for hearing system Used in P-MEI or T-MEI Converts mechanical vibration into electrical signal