View
1.028
Download
4
Category
Preview:
Citation preview
UPPER LIMB PROSTHESISUPPER LIMB PROSTHESIS
Astha PatniAstha Patni
IntroductionIntroduction• Upper limb prosthesis designed to
replace, as much as possible, the function or appearance of a missing limb or body part
• Prosthesis can replace some grasping and manipulating functions of hand
• No sensory feedback• Role of dominant function replaced to
contra-lateral hand and prosthesis assists bimanual function
• A successful prosthesis – comfortable to wear– easy to don and doff– light weight and durable– cosmetically pleasing– must function well mechanically– have reasonable maintenance– motivation of the individual
• Factors – Amputation level – Expected function of the prosthesis – Cognitive function of the patient – Vocation of the patient – Avocational interests of the patient – Cosmetic importance of the prosthesis – Financial resources of the patient
• Reasons for upper limb amputation – 0-15 years: Correction of a congenital
deformity or tumor – 15-45 years: Trauma, tumor – 60 years: Rare ; tumor or medical
disease
AMPUTATION LEVELSAMPUTATION LEVELS• Transphalangeal amputation: Resection of the
thumb or fingers at distal interphalangeal (DIP), proximal interphalangeal (PIP), or metacarpophalangeal (MCP) levels, or at any level in between
• Transmetacarpal amputation: Resection through the metacarpals
• Transcarpal amputation: Resection through the carpal bones
• Wrist disarticulation: Transection between the carpals and radius/ulna
AMPUTATION LEVELSAMPUTATION LEVELS• Transradial amputation: Below-elbow amputation
(may be classified as long, medium, or short)
• Elbow disarticulation: Transection through the elbow joint
• Transhumeral amputation - Above-elbow (Standard length is 50-90% of humeral length.)
• Shoulder disarticulation: Transection through the shoulder joint
• Interscapulothoracic disarticulation (forequarter): Amputation removing the entire shoulder girdle (scapula and all or part of the clavicle
TYPES • Body powered or conventional• External powered or electric • Cosmetic or passive• Hybrid
Body powered or Body powered or conventionalconventional
• Pros– low cost– Moderately lightweight– Most durable
• Cons– Most body movement to operate– Most harnessing– Least satisfactory appearance
External powered or electricExternal powered or electric• Pros
– Moderate or no harnessing– Least body movement to operate– Moderate cosmesis– More function – proximal levels
• Cons– Heaviest – Most expensive– High maintenance– Limited sensory feedback
Cosmetic or passiveCosmetic or passive• Pros
– Most lightweight– Best cosmesis– Least harnessing
• Cons– High cost if custom made– Least function
Upper limb prosthesisUpper limb prosthesis• Prosthetic components
– Terminal devices– Wrists– Elbows– Shoulders
• Socket • Suspension
Terminal devicesTerminal devices• Functional activities of hand
– Non prehensile– Prehensile
Terminal devicesTerminal devices• Non prehensile
– Touching, feeling, pressing down with fingers, tapping, vibrating the cord of musical instrument, lifting or pushing with hand
• Prehensile– Precision grip (i.e. pincher grip), Tripod
grip, Lateral grip, Hook power grip, Spherical grip
Terminal devicesTerminal devices• Active
– Hooks– Functional hands– Activity specific devices
• Passive– Cosmetic hands
Hook / Hand
Mechanical Electrical
VO VC Electrical Myoelectric
Digital Proportional
PassiveActive
Terminal devicesTerminal devices• Lack sensory feedback• Limited mobility and dexterity
• Hand – three-jaw chuck• Hook – lateral pinch
Terminal devicesTerminal devices• VO
– Practical– In closed position, by springs– Patient pulls the cable to open– Prehensile force – spring
• VC– Physiological– In open position– Patient pulls the cable to close– Prehensile force – patient – Greater proprioceptive input
Voluntary-Closing HooksVoluntary-Closing Hooks
• APRL hook developed by the Army Prosthetics Research Laboratory
Voluntary-Opening Hook Voluntary-Opening Hook Terminal DevicesTerminal Devices
• Hosmer-Dorrance work hooks• Sierra two-load hook • United States Manufacturing
Company (USMC) hook • CAPP terminal device (originally
developed at the Child Amputee Prosthetics Project at UCLA)
• Otto Bock and Hugh Steeper
. Voluntary-opening hook-. Voluntary-opening hook-type terminal devicetype terminal device
Voluntary-Closing HandsVoluntary-Closing Hands
Otto Bock system hands
Voluntary-Opening HandsVoluntary-Opening Hands
• Becker Plylite Hand• Becker Lock-Grip and Imperial
Hands.• Robin-Aids Mechanical Hand• Robin-Aids Soft Mechanical Hand• Sierra Voluntary-Opening Hand• Hosmer-Dorrance Functional
Hands
ELECTRIC TERMINAL DEVICESELECTRIC TERMINAL DEVICES
Hand like shape
• Otto Bock System Electric Hands
• Steeper Electric Hands
Not having hand like shape
• Otto Bock System Electric Greifer
• Hosmer NU-VA Synergetic Prehensor
• Steeper Powered Gripper
• NY-Hosmer Prehension Actuator
Otto Bock System Electric Hand (left) and Steeper Electric Hand (right). A with mechanism covered by handlike shells; B with internal mechanism exposed.
• A "palmar" and B lateral views of the Steeper Powered Gripper (left), Otto Bock System Electric Greifer (center), and Hos-mer NU-VA Synergetic Prehensor (right).
Myoelectric controlMyoelectric control
• tranradial myoelectric prosthesis (Otto Bock type) The system uses two myoelectric sites on the residual limb. the signal flow in a two-site, two-function myoelectric hand prosthesis
Activity specific devicesActivity specific devices• Farming• Construction• Cooking• Photography • Sports: golf, fishing, skiing
Cosmetic glovesCosmetic gloves• Digit, hand, extend
till elbow• Custom made
silicone cosmetic covers – expensive and difficult to maintain
Prosthetic wristsProsthetic wrists• Provide receptacle for connecting
terminal device• Pronosupination or flexion based on
functional activities of patient
Prosthetic wrists Prosthetic wrists Types• Mechanical
– Pronosupination• Friction (Can rotate)• Quick-disconnect• Spring-assisted (B/L amputee)
– Flexion (B/L amputee , longer side)• Spring-assisted internal or external
Prosthetic wristsProsthetic wrists• Electric (B/L trans-humeral)
– Pronosupination• Myoelectric (B/L amputee)• Switch control
Friction wrist units. Friction wrist units.
Round and oval configurations Round and oval configurations of constant friction wrist unitsof constant friction wrist units
Quick-change wrist unitsQuick-change wrist units
Flexion wrist unitsFlexion wrist units
Electric wrist unitsElectric wrist units
• The Otto Bock Electric Wrist Rotator. The rotator, shown alone at the bottom, mechanically and electrically interfaces with the quick-disconnect adaptor of the System Electric Hand or Greifer
Prosthetic elbowsProsthetic elbowsClassification• Body-powered elbow
– External with or without spring assisted flexion (elbow disarticulation)
– Internal, with or without spring assisted flexion
– Internal, with rotating turntable (allows internal/ external rotation)
Prosthetic elbowsProsthetic elbows• Externally powered elbow
– Digital switch control– Proportional switch control– Digital myoelectric control– Proportional myoelectric control
• Passive elbow– Manual lock
Elbow units Elbow units Flexible hinges Rigid hinges
Elbow Elbow Polycentric hinges Step up hinges
ELBOW UNITELBOW UNIT
OUTSIDE LOCKING INSIDE LOCKING
Electrical powered elbowsElectrical powered elbows
• Boston Elbow,• NY-Hosmer Electric Elbow, • Utah Arm. These elbows differ from one another
in mechanical configuration, drive mechanism, and control options.
Prosthetic socketsProsthetic socketsFunctions
– Comfortable residual limb – prosthesis interface
– Efficient energy transference to the prosthesis
– Secure suspension of the prosthesis– Adequate cosmesis
Prosthetic socketsProsthetic sockets• Wood
– Chronic edema– Trophic skin changes
• Plastic – Total contact– Decreased weight– Increased durability
Prosthetic socketsProsthetic sockets• Two layers
• Inner-contoured to the residual limb• External- gives length and shape
• Components are attached to external layer
Prosthetic socketsProsthetic sockets• Process
– Negative impression of residual limb (POP)– Positive mold– Modify positive mold (remove from
pressure tolerant and add to pressure sensitive)
– Transparent / check socket – Trial fit and modify– New positive mold– Final socket
Negative mold
Positive mold
socket
Various socketsVarious sockets• Wrist disarticulation socket• long Below elbow socket• Short below elbow socket• Very short below elbow socket [ Split sockets] Muenster sockets
• Elbow disarticulation socket• Standard above elbow socket• Short above elbow socket• Shoulder disarticulation socket• Forequarter amputation socket
Suspension systemsSuspension systems• Functions
– Suspension – securing prosthesis to residual limb
– Control of prosthesis / terminal devices• Types
– Harness• Figure of 8 (traditional)• Chest strap (proximal amputation)• Shoulder saddle (proximal amputation)
Harness
Suspension systemsSuspension systems• Self suspension
– Condylar– Muenster (Self suspending; Not
preferred in B/L transradial amputation)– Northwestern
• Semisuction– Hypobaric– Semisuction
• Suction– Full suction– Silicone sock
Suction suspension preferred for Tranhumeral amputee with normal contrlateral limb
• Sock• Interface between residual limb and
socket• Layers adjustable to volume changes• Protect skin and improve hygiene• Socks with special silicone band and
socket with one way valve are used in semisuction type of suspension systems
Silicone suction suspensionSilicone suction suspension• Kristinsson in 1986• Improved suspension with negative
atmospheric pressure• Reduction of shear forces on skin• Allows volume adjustment with
residual limb girth changes• Simplified donning, better elbow
range of motion, lighter
Silicone suction suspensionSilicone suction suspension• Silicone sleeve with distal
attachment pin that fits into shuttle lock mechanism in socket
• Rolls silicone liner directly over skin after spraying alcohol
• Socks over silicone to improve fit
Silicone suction suspensionSilicone suction suspension• Patients with problems of skin
integrity– Skin grafting for burns, – degloving injury, – insensate skin (diabetes, scleroderma),– adhesive scar tissue
Control mechanismsControl mechanisms• Body powered (harness)
– Scapular abduction– Chest expansion– Shoulder depression, extension,
abduction, flexion– Elbow flexion, extension
• Discomfort• Less cosmetic
MECHANICS OF THE BELOW-ELBOW (TRANSRADIAL) CONTROL SYSTEM
• Glenohumeral joint flexion for operating a terminal device.
HEAVY-DUTY HEAVY-DUTY TRANSRADIAL HARNESS TRANSRADIAL HARNESS
BILATERAL TRANSRADIAL BILATERAL TRANSRADIAL HARNESSHARNESS
TRANSHUMERAL CONTROL TRANSHUMERAL CONTROL
SYSTEMSYSTEM Two types of
control cable
1.Elbow flexion/terminal device control cable
2.Elbow lock control cable
Trans humeral hareness controlTrans humeral hareness control
The operating sequence of the two The operating sequence of the two cable systems cable systems
• Tension applied to the elbow flexion/terminal device control cable causes the elbow to flex;
• When the desired angle of elbow flexion is achieved, the rapid sequential application and release of tension on the elbow lock control cable locks the elbow
• With the elbow locked, the reapplication of tension on the elbow flexion/terminal device control cable permits operation of the terminal device
SHOULDER DISARTICULATION SHOULDER DISARTICULATION HARNESSHARNESS
Control mechanismsControl mechanisms• Externally powered prostheses• Electric motors inside prosthesis for
wrist rotation / elbow flexion or extension
• Motors controlled by switches, myoelectric signals, acoustic signals
Control mechanismsControl mechanismsSwitch
• Inside or outside socket• Activated on contact by amputee
Control mechanismsControl mechanismsMyoelectric controls
• Electrical activity generated during muscle contraction to control flow of energy from a battery to a motor in prosthetic device
• Antagonistic muscles in distal portion with normal voluntary activity
Control mechanismsControl mechanismsMyoelectric controls
• Electrodes inside socket detect muscle action potentials, amplify them to turn on motor which brings about movements
• Single channel: two electrode sites, one for each function (open & close terminal device)
• Multi-channel: single electrode, amplitude of signal determines function
Control mechanismsControl mechanismsMyoelectric controls
• High cost• Low reliability• Heavy (motors, batteries)
– India: electrodes rust quickly because of sweat, electronic circuits fail due to dust / sweat
Prostheses by level of Prostheses by level of amputationamputation
Prostheses by level of Prostheses by level of amputationamputation
Partial hand• Prosthesis not necessary• Surgical reconstruction – opposition – for
prehension with proprioception
Prostheses by level of Prostheses by level of amputationamputation
• Wrist disarticulation– Distal radial-ulnar articulation preserved
for prono-supination– Socket: tapered and flattened distally
forming an oval shape– Wrist unit: thin, to minimize length– Cosmetically: trans radial
Prostheses by level of Prostheses by level of amputationamputation
Transradial amputationClassification (based on length)
• Very short (<35%): rigid elbow hinges• Short (35-55%): <60º pronosupination,
flexible elbow hinges• Long (55-90%): 60-120 º
pronosupination, flexible elbow hinges
Below elbow prosthesis
Prostheses by level of Prostheses by level of amputationamputation
Transradial amputation with decreased elbow ROM• Polycentric elbow joints or split socket
with step-up hinges used to provide additional flexion
• Decreased elbow flexion power
Prostheses by level of Prostheses by level of amputationamputation
Elbow disarticulation• Sockets: flat and broad distally (like
epicondyles)• External elbow joint with cable operated
lock in medial joint• Suspension: figure of 8, shoulder saddle,
chest strap• Control system: 2 cables, one to lock the
elbow, other opens terminal device or flexes elbow
Prostheses by level of Prostheses by level of amputationamputation
Transhumeral amputationClassification (based on length of
humerus)• Very short (<30%)• Short (30-50%)• Standard (50-90%)
Prostheses by level of Prostheses by level of amputationamputation
Transhumeral amputation• Sockets:
– Residual limb greater than 35% - proximal trimline within 1cm of acromion, suspension with figure of 8, shoulder saddle, or chest strap
– Residual limb smaller than 35% - proximal trimline 2.5cm medial to acromion, suspension with chest strap or suction socket
Prostheses by level of Prostheses by level of amputationamputation
Transhumeral amputation• Elbow joint
– Internal elbow joint• Preferred • Level of amputation 4 cm or more proximal from
epicondyles• Allows passive internal / external rotation• Elbow spring-lift assist available
– External elbow joint• Distal amputation• Maintains elbow center with contralateral side
Prostheses by level of Prostheses by level of amputationamputation
Transhumeral amputation• Control system
– Dual cable (like elbow disarticulation)
Above elbow prosthesis
Above elbow prosthesis
Shoulder disarticulation and Shoulder disarticulation and forequarter amputationforequarter amputation
• Socket– Extends to thorax– Open –frame socket to decrease weight
and heat• Similar to transhumeral + shoulder
unit
Bulk headFlex / ext
Universal
Shoulder disarticulation and Shoulder disarticulation and forequarter amputationforequarter amputation
• Control: – Triple cable system– One for elbow flexion when opposite
humerus is flexed– Second cable opens terminal device
with chest expansion– Third cable locks / unlocks elbow with
chin / opposite hand
Shoulder disarticulation and Shoulder disarticulation and forequarter amputationforequarter amputation
• Externally powered prosthesis preferred
• Passive cosmetic prosthetic restoration in some patients
Recommended