UPPER LIMB FUNCTIONAL PROSTHESIS

UPPER LIMB FUNCTIONAL PROSTHESIS

A Prosthesis is a device that is designed to replace, as much possible , the function or appearance of a missing limb or a body part.CHARACTERISTICS OF A SUCCESSFUL PROSTHESIS: Comfortable to wearEasy to put on and removeLight-weightDurableCosmetically pleasingMust Function well mechanicallyRequire only reasonable maintainace.Finally, Prosthetic use largely depends on the motivation of the individual, as nothing matters if the patient does not wish to wear prosthesis.

CONSIDERATIONS WHEN CHOOSING A PROSTHESIS: Amputation levelContour of the Residual limbExpected function of the ProsthesisCongnitive funtion of the PatientVoacation of the Patient (Desk Job vs Manual Labour)Avocational interests of the Patient (e.g; Hobbies)Cosmetic Importance of the ProsthesisFinancial resources of the Patient.Reasons for an Upper Limb Amputations:THIS IS MOSTLY CORRELATED BY AGE.

(0-15 years) CONGENITAL DEFORMITY OR TUMOR

(15-45 years) TRAUMA

(>60years) SECONDARY TO TUMOR OR MEDICAL DISEASE

AMPUTATION LEVELS:Trans-Phalangeal AmputationDIPPIPMCPAnywhere in Between.Trans-Metacarpal AmputationTrans Carpal AmputationWrist DisarticulationTrans-Radial AmputationElbow DisarticulationTrans-Humeral AmputationShoulder DisarticulationForeQuarter (Inter-Scapular Disarticulation).

TYPES OF PROSTHESISCOSMETICFUNCTIONAL

Mostly passive or cosmetic types on one end to primarily functional types on the other. The purpose of most prosthesis falls somewhere in between.

Cosmetic prosthesis look extremely natural but they often are more difficult to clean, can be expensive and usually sacrifice some function for increased cosmetic appearance.

TYPES OF FUNCTIONAL PROSTHESIS:BODY-POWERED PROSTHESIS (Cable Controlled)

EXTERNALLY POWERED (BATTERY) PROSTHESIS (Electrically Controlled)MYOELECTRIC PROSTHESIS SWITCH-CONTROLLED PROSTHESIS.BODY-POWERED PROSTHESIS:ADVANTAGESDISADVANTAGESModerate CostMost Body Movements needed to operateModerately Light WeightMost HarnessingMost DurableLeast Satisfactory appearanceHighest Sensory FeedbackIncreased Energy ExpenditureVariety of Prehensors available

PATIENT CONTROLLED BATTERY-POWERED (MYO-ELECTRIC/SWITCH CONTROLLED)ADVANTAGESDISADVANTAGESModerate or no HarnessingHeaviestLeast Body movements needed to operateMost expensiveModerate CosmesisMost MaintainceMore Function; Proximal Areas, stronger grasp/grip in some casesLimited Sensory FeedbackExtended therapy time for training.

MYO-ELECTRICAL CONTROL SYSTEMS:2-site/2-function (Dual Site) System:Separate electrodes for paired prosthetic activity. FLEXTION/EXTENSION, SUPINATION/PRONATION.It is more physiological and easier to control.

2. 1-site/2-function (Single Site) System:

Used when limited control sites (MUSCLES) are available in a residual limb. This system uses 1 electrode to control both funtions of a paired activity (Flextion/Extension), (Supination/Pronation).

SWITCH CONTROL SYSTEMS:Switch controlled externally powered prosthesis utilize small switches, rather than muscle signals, to operate the elecric motors.A switch can be activated by movement of a remanant digit or part of a bony prominance against the swithch or by a pull on a suspension harness (similar to movement a patient makes, when operating a body-powered prosthesis)This can be a good option to provide contol for external power when myoelectric control sites are not available or when the patient can not master myoelectric control.

Switch control battery powered TYPICAL COMPONENTS OF AN UPPER-LIMB BODY-POWERED PROSTHESIS:All conventional body-powered prosthesis have following components:SOCKETSUSPENSIONCONTROL-CABLE SYSTEMTERMINAL DEVICECOMPONENTS FOR ANY INTERPOSING JOINTS AS NEEDED ACCORDING TO THE LEVEL OF AMPUTATION.1. SOCKET:It has a Dual-wall design

Rigid inner socket to fit patients residual limb

Outer wall designed to be of same length and contour as that of opposite limb.

2. SUSPENSION:HARNESS BASED SYSTEMSFigure of 8Shoulder saddle with chest strapFigure of 9.SELF SUSPENDING SOCKETSSUCTION SOCKETS.

The suspension system must hold the prosthesis securely to limb as well as accommodate and distribute forces associated with weight of the prosthesis and any super-imposed fitting devices.

The patient with a transradial amputationdemonstrates 2 types of harnessing:

The figure-8 harness; The shoulder saddlewith chest-strap suspension

C & D: For the patient with a transhumeral amputation

3. CABLE CONTROL SYSTEMSingle Control Cable (Bowden Cable System)

Dual Control Cable System (Fair-lead Cable System).

BODY MOVEMENTS CAPTURED FOR PROSTHETIC CONTROL:Gleno-Humeral Forward Flexion.Gleno-Humeral Depression/Elevation, Extension, AbductionNudge Control (for more complex cases neeeding many control functions).4. TERMINAL DEVICEThe major function of a hand that a terminal device tries to replicate is GRIP (PREHENSION).There are 5 types of grip;Precision Grip (Pincher Grip)Lateral Grip (Key Pinch)Tripod Grip (Palmer Grip/3-Jaw Chuk Pinch)Hook-Power GripSpherical GripTypes of Terminal Devices:Passive Terminal Devices (More Cosmetic than Functional)Functional e.g Child Mitt used on infants first prosthesis to assist in crawling.Cosmetic.Active Terminal Devices (More Function than Cosmetics)Can be both Body Powered (Cable controlled)Externally Powered (Electrically controlled).

Cable controlled Active terminal devices can beVoluntary opening devicesVoluntary closing devices

Active terminal devices can be either prosthetic hands or Hooks.

PROSTHETIC HANDSPLIT HOOKHeavier in weightLighter in WeightMore difficult to see objects being graspedEasier to see objects being graspedMore complex MechanicallySimpler MechanicallyLess Versatile as a ToolVersatile as a ToolCannot get into pocketsWill fit into PocketsMore cosmetic in appearanceNot cosmetic

PROSTHETIC HANDPROSTHETIC HOOK5. COMPONENTS FOR ANY INTERPOSING JOINTS AS NEEDED ACCORDING TO THE LEVEL OF AMPUTATIONWRIST UNITS

ELBOW UNITS

SHOULDER AND FOREQUARTER UNITSA. WRIST UNITS:The wrist unit provides orientation of the terminal device in space. Once positioned, the wrist unit is held in place by a friction lock or a Mechanical lock.

Quick-Disconnect Wrist UnitEasy swapping of terminal devices that have special functions.Locking Wrist UnitTo prevent rotation during grasping and lifting.Wrist Flexion Unit Improved function of midline activities e.g; shaving, buttoning, perineal care.

WRIST UNITB. ELBOW UNITS:Elbow units are chosen based on te level of amputation and the amount of residual limb. It is helpful to remember that supination and pronation of the forearm decreases as the site of amputatin becomes more proximal.Flexible Elbow HingeMedium and Long TransRadial AmputationsWrist Disarticulations

Rigid Elbow Hinge Short Transradial Amputation

Internal Locking Elbow Joint Transhumeral Amputation.Internal Elbow allows 135 degree flexion and can be locked into different flextion positions

ELBOW UNITC. SHOULDER AND FOREQUARTER UNITSFOR AMPUTATIONS AT SHOULDER AND FOREQUARTER LEVELS.In cases of amputations at these levels, function is very difficult to restore due to;Weight of the prosthetic componentDiminished overall function when combining multiple prosthesis.Increased energy expenditure required to operate the prosthesis.

Thus, patients mostly choose either;A purely cosmetic prosthesis to improve body image and fit of their cloths.No prosthesis at all.

SHOULDER UNITOVERALL TIMELINES FOR AN AMPUTATION & PROSTHESIS FITTING:FOUR STAGES;

PRE-AMPUTATIONSURGICAL PROCEEDUREACUTE POST SURGICAL AMPUTATIONPROSTHESIS FITTING AND TESTING1. PRE-AMPUTATIONPatient must be seen by Re-habilitation team pror to the surgery to;

Evaluate post operative needs and desiresDiscuss Prosthetic RestrorationBegin any range of motion exercises (ROM)Strengthening and training in Activities of Daily Livings (ADLs)Provide peer support of another successful amputee.2. SURGICAL PROCEDURESeveral actions can be taken to maximize the function of residual limb.Bevelling the Bone End (Helps to minimize soft tissue trauma by sharp/irregular bones)Gentle traction while severing a nerve (Resulting Neuroma forms in soft tissue with less post surgical pain)Myoplasty (Agonist-antagonist muscles are stitched to each other)Myodesis (Residual muscles are stiched to the bone).Ensuring proper length so that specific prosthetic components can be used that may look cosmetically more pleasing and achieve functional goals.3. ACUTE POST SURGICAL PERIOD:The major physical issues in this phase are;Adequate wound healingPain ManagementInstructions in performance of ADLsMobilityROMStrengthDuring this phase a programe to prepare the residual limb for prosthesis should be initiated.Skin desensitization should be done;Gentle tapping on distal portion to mature siteMassage to prevent excessive scar formationEdema controlPsycology should be involved at this stage if possible. This addresses;SurvivalRecoveryIntegration

The patient will need to be followed through out the course of immediate Post-amputation, prosthetic fitting and functional re-integration back into his/her social life routine.4. PROSTHESIS FITTING AND TESTING:In young patients with traumatic amputation IPOP (Immediate Post Operative Prosthesis) which is a temporary prosthesis, can be fitted during surgery.In older patients or in those with vascular disease, a prosthesis is not fitted until the suture line has completey healed.Prosthesis are either Preparatory or Definitive (Permanent).

FITTING AN UPPER LIMB AMPUTEE WITH A BODY-POWERED PREPARATORY PROSTHESIS WITHIN 7-30 DAYS IS ADVISABLE. THIS IS CALLED AS THE GOLDEN PERIOD.THANKYOU!