Myo Electric Hand
Myoelectrically Controlled Prosthesis for Wrist Disarticulation
Hybrid Prosthesis for Above-Elbow Amputation
For patients with traumatic or congenital absence of forearm(s) and hand(s), the myoelectrical hand prosthesis is an alternative to traditional hook prostheses. These prostheses are more versatile and simpler to use than traditional hooks with a stronger pinch force, better grip and are more versatile.
The electric motor-driven hands, wrist, and elbows are controlled with myoelectric power. In the prosthesis socket, surface electrodes make contact with the skin and sense and amplify the potential for muscle movement from the voluntary contraction of muscle in the residual limb. In order to provide a feature (e.g., terminal unit operation, wrist rotation, elbow flexion), the amplified electrical signal turns on an electric motor. Multiple functions are performed by the newest electronic control systems , allowing elbow motion, wrist rotation and hand movements to operate sequentially.
In contrast to “hook” prostheses, myoelectrical hand prostheses provide enhanced function and functional role range. Myoelectric hand prostheses can be used in patients with congenital limb defects and in patients with trauma or surgery-related amputations. For both above-the-elbow and below-the-elbow amputees, and for both unilateral and bilateral amputees, the unit is suitable. In order to be considered a candidate, patients must have a minimum microvolt threshold (i.e. the minimum intensity of the microvolt signals produced by the residual arm musculature) and pass a control test.
Myoelectrical hand prostheses are indicated for persons at least one year of age or older. Children with congenital absence of the forearm(s) and hand(s) are usually fitted with a conventional passive prosthesis until approximate age 12 to 16 months, at which time they may be fitted with a myoelectrical prosthesis.
Myoelectrical hand prostheses generally come with a one-year warranty for parts and labor. The motor and drive mechanisms typically last 2 to 3 years and may need to be replaced after this period. When used on a child, the sockets may need to be replaced every 12-18 months due to growth. With heavy use, the entire prosthesis might require replacement by the fifth year.