Among the more challenging pediatric hand presentations are upper limb deficiencies. These can result from congenital or acquired causes. Each of these deficiencies brings its own unique challenges, which will be discussed later in this chapter.
The Center for Disease Control and Prevention estimates 4 out of every 10,000 babies or about 1500 babies per year are born with upper limb reductions. Limb reduction can be due to genetic factors, exposure to chemicals, viruses, taking certain medications while pregnant, or by amniotic tissue becoming tangled with arms or legs. Additionally, other birth defects of organs and tissue, typically heart and kidneys, can be associated with limb deficiencies. The child may face varying degrees of challenge because of limb reduction. These challenges are dependent on the extent and location of the reduction. Some limitations could include delays in normal development of motor skills, limitations in performing activities of daily living (ADLs), and possible impact of social–emotional well-being due to their appearance.
Acquired limb amputations are caused by either trauma or disease. Trauma causes twice as many amputations as disease. Over 90% of amputation injuries involve fingers. For children age 0–2 finger amputations increase to 95.2%. The most common cause of finger amputations in pediatrics is a result of being “caught between” objects such as a door. Other traumatic causes of limb loss in childhood include recreation, thermal injuries, household accidents, railroad accidents, gunshot or explosion, and vehicular. Diseases that may result in upper limb loss include tumors, blood vessels or nerve abnormalities, and severe infections ( Table 6.1 ).
| Mechanism | Percent | Example |
|---|---|---|
| Caught between | 16.3% | Doors Primarily digits |
| Machinery | 15.6% | Farm equipment Table saws—school wood shop Power lawn mowers—lower limb |
| Motor vehicle collisions | 8% | Shoulder/upper arm—61% Forearm/elbow—31% Hand/wrist—13.8% |
| Firearms | 6.1% | Primarily lower extremities, but can be fingers |
| Off-road vehicles | 6.1% |
Multiple limb amputations are a rare occurrence. Amputations of all four limbs, or quadrimembral amputee, are even rarer (less than 1%) in pediatrics. Causes of four limb amputations include electrical burns, complications of renal disease, and ischemic gangrene resulting from septic conditions. Prosthetic implications and considerations are highly dependent on the level of amputation and current level of physical and cognitive functioning.
Level of Amputation
The length of the residual limb can impact performance of functional activities. Amputations of the upper extremity are described by location. Upper extremity amputations can be partial or full, as well as unilateral or bilateral. The separation of the carpal bones from the radius and ulna is called as a wrist disarticulation. Amputations through the radius and ulna are referred to transradial (below the elbow) amputations. This can further be classified as long, medium, or short residual limb. When the ulna and radius are removed, but the humerus remains intact, this is called an elbow disarticulation. Transhumeral (above the elbow) amputation can be classified as long, mid, or short transhumeral amputation. Length of the residual limb impacts decision-making for prosthetic devices and will be discussed later in this chapter. Shoulder disarticulation is when there is less than 30% of the humerus remaining. Scapulothoracic amputation is when part or all of the clavicle and scapula are removed.
Transverse Versus Longitudinal Deficiencies
The International Society for Prosthetics and Orthotics developed a classification for congenital limb deficiencies. These deficiencies have been categorized as transverse or longitudinal. In the case of transverse deficiencies, “the limb has developed normally to a particular level beyond which no skeletal elements exists, although there may be digital buds.” These are named where the limb terminates (example: carpal, forearm, shoulder) and further described as total, partial, upper, middle, or lower third .
A longitudinal deficiency is a “reduction or absence of an element within the long axis of the limb.” There can be normal skeleton distal to the affected bones. When describing longitudinal deficiencies, the affected bones are named, beginning proximally and moving distally. Bones not named are considered normal. To further classify, bones are identified as totally or partially absent. In the case of partially absent, location can be added. The digits affected should be related to metacarpals and phalanges and numbered from the radial side (thumb = 1). The term “ray” can be used to describe these relationships.
Prosthetic Acceptance and Rejection
There are several studies looking at factors impacting acceptance and rejection of upper extremity prosthetic devices. The physical factors influencing acceptance of the device include: fit, comfort, weight of the device, repeated mechanical failure, lack of tactile sensation, and/or whether the prosthesis is unnatural looking (hook). The psychosocial factors impacting acceptance of the device include negative reactions by others, low self-esteem, lack of acceptance of disability, unrealistically high expectations, and poor initial prosthetic experiences.
Studies in adults suggest that early training with an experienced clinician, proper fitting, and functional training with an experienced team are critical to prosthetic acceptance. The level of amputation is also a contributing factor in accepting a prosthesis. Shoulder disarticulation has the highest rate of rejection at 60%. Next is transhumeral rejection rate at 57% and transradial at 6%. The average rate of rejection is approximately 35%–45%. Individuals with multilimb amputations tend to have higher rejection rates of their upper limb prosthetic(s). They can adapt amazingly well, but continue to experience deficits with completing some aspects of ADLs, such as opening containers for self-feeding and toileting skills.
A study by Vasluian et al. found the most common reasons to wear a prosthetic were cosmesis, improved function, manipulation, specific activities, muscle development, locomotion, posture, and balance. The subjects who did not use their prostheses identified cosmesis (did not look normal), being more functional without the prosthesis, technical and interface reasons, too heavy, discomfort and physical fatigue, and pain as reasons to not use a prosthetic device. Children often learn to adapt and use their deficient limb functionally without a device (see Image 6.1 ).
A consideration that should be discussed with the child and family are the potential long-term effects on the musculature of the dominant side, or the nonaffected extremity, due to compensation and over use over time. It is still unclear if prosthetic use can reduce overuse injuries, but it can be a necessary tool in adulthood to manage functional tasks in the event of pain or disability of the intact limb.
Developmental Stages and Implications for Fitting
When considering fitting of prosthetics for children and adolescents there are multiple factors to consider, which fall into three main areas: physical, psychosocial, and environmental ( Table 6.2 ).
| Physical | Psychosocial | Environmental |
|---|---|---|
| Age Level of amputation Number of missing limbs Skin condition Edema Residual strength Range of motion and excursion Pain Muscle sites available for myoelectric control Size of the child | Developmental status Cognition Values Adjustment or acceptance by child and parent Interests Roles and responsibilities Financial resources Family readiness and “buy in” | Functional demands Access to prosthetic services and maintenance Climate/Weather Cultural influences Places in which the child lives, plays, and participates in school and community |
There are some basic guidelines, but each case should be considered individually, and no one approach works for every case. Generally, it is a very emotional and traumatic time for families whether they are faced with a congenital or traumatic limb difference. The psychosocial adjustment can be just as important as the child’s physical attributes to ensure the success of any prosthetic intervention. As this is a very unique population, it is imperative to work with a cohesive team with prosthetic experience and knowledge. Disciplines represented on the team could include physiatrist, orthopedic surgeon, prosthetist, occupational therapist, and physical therapist. Often, a social worker, psychologist, or nurse is included in the team. As this is a very unique population, it is important to have practitioners with upper limb prosthetic experience and knowledge. Education of the family and child is key and referrals to the team should happen as soon as possible. The team should present all options and answer questions as early as possible, so that informed decisions can be made. Different from the treatment of adults, children’s needs and abilities are constantly changing through their developmental progression. Consideration needs to be made of a child’s physical capacity, cognitive skills, attentional skills, functional demands, interests, and psychosocial needs. These factors will often change over time. For example, the goal for a 2-year old with a below elbow amputation would be basic grasping abilities required for two-handed play. A body-powered or myoelectric prosthesis would meet the child’s needs. However, a teenage girl who wants to do gymnastics, play the cello, and has significant concerns about cosmesis may require multiple devices to meet her needs. Evidence from one study suggests that the provision of multiple prosthetic options may result in longer periods of wear.
The residual limb length is also an important consideration. Children with above elbow and longer transradial residual limbs, specifically those with wrist or partial hand, tend not to accept prostheses. Similarly, a very short transradial amputation presents significant challenges for fitting. Myosite options may be limited, and suspension and tolerance of the weight of a prosthesis is more difficult. If the amputation is a result of a burn, a myoelectric may not be the best option due to skin integrity and dryness, causing impediment of the myoelectric signal. Prosthetic sockets can be hot and uncomfortable, and with a rapidly growing child, may be a significant hurdle to overcome for prosthetic success. The weight of a prosthesis is also a consideration and often contributes to the success or failure of fitting. Myoelectric prosthetics are heavier and require intimate fit with skin contact for the electrodes. On the other hand, body powered prosthetic users have to deal with either a figure 8 or 9 harness that can be uncomfortable and cause issues with clothing and cosmesis.
The following chart is a general list with guidelines for prosthetic choices related to age. It is important to consider each child individually. This list is not intended to be prescriptive for every case, and does not include every option. The importance of collaboration with a knowledgeable team and the patient and family cannot be over stressed ( Table 6.3 , Image 6.3 ).
Type of Componentry | Description | Age Range and Most Appropriate Level of Amputee | Advantages | Challenges |
|---|---|---|---|---|
| Infant/toddler mitt/hand passive | Passive lightweight mitt or foam-filled hand (fisted or open) Usually attached to self-suspending socket | 3–18 months short to midlevel transradial 6–24 months transhumeral Long Transradial Partial hand and shoulder disarticulation levels generally less appropriate | Cosmetic May help to provide balance Establishes wearing tolerance May provide a better weight-bearing surface for crawling May improve incorporation of prosthetic into body image | Takes away sensation of residual limb Functionally limiting, a hand or terminal device that can allow passive insertion of toys initially by adult and then by children tends to be preferable for older infants and toddlers |
| Passive split hook, reverse ADEPT or mechanical hand | A terminal device (TD) attached to a socket that does not have any type of cable but has a passive closing force | 6–24 months transradial 12–36 months transhumeral Long Transradial, partial hand and shoulder disarticulation levels generally not appropriate | Allows for passive grasp usually by adult placing objects into TD Facilitates early bimanual incorporation of a prosthesis | Depending on the choice of TD may be less cosmetic Grasp force limited Some limitations on size of object that can be held |
| Preflexed or Banana elbow | Prosthetic socket that is formed in 30–45 degrees of flexion at elbow level | 12–36 months transhumeral | Allows for TD to be in position for midline hand use Has a natural appearance | Limited reach Unable to get hand to face without compensatory shoulder movement |
| Passive elbow | Friction elbow joint that allows adult or child to position elbow in flexion or extension | Usually an option for younger transhumeral or shoulder disarticulation | Allows for passive positioning of the elbow to put the TD in a greater variety of planes to reach from face to leg Lighter in weight than body powered elbow | Joint less stable Requires use of intact limb or use of a surface to independently push into position |
| Voluntary opening TD such as Split hook, CAPP, and mechanical hand | TD that is controlled by cable for opening, force of closure provided by a spring or rubber band Suspension figure 8 or 9 harness | Can be used by any child that has skills for learning TD operation (usually 18 months or older) | Easier to control than voluntary closing Split hook allows best visual access during operation for grasp | Grip strength is often limited Rubber bands wear out and need changing Mechanical hand is the most difficult VO TD to use because vision of grasp can be occluded and resistance is greatest for opening |
| Voluntary closing TD such as ADEPT or mechanical hand | TD that is controlled by cable for closing force | Can be used by any child who has skills for learning TD control (usually 18–24 months) | May be more difficult to train younger children Requires sustained movement for activation to maintain grasp (there is a locking mechanism that can be added) | Gives proprioceptive feedback for grasp force More control of force Better grasp of cylindrical objects |
| Myoelectric hand | TD that is controlled by electrical signals from muscles in the residual limb | Possible to be fitted at any age from 12 months to adult. Best age for younger fitting appears to be around 2 ½ | Reliable strong grip Cosmetic No harness Can adjust sensitivity of electrodes Options for on off, variable or proportional control Single electrode “cookie crusher” operation mode for younger children | Cost High maintenance Weight can be heavier Does not hold up to sand dirt and heavy activities Requires tight fit without use of stump sock resulting in complaints of heat and sweat Glove durability problematic Requires battery charging |
| Body-powered elbow | Suspension figure 8 Locking joint is controlled by shoulder extension, abduction and depression Once unlocked elbow is positioned with same action as TD control | Tends to work better for children over 36–48 months Pull tab can be used for younger children for lock | Provides more degrees of freedom for TD positioning Can also get internal rotation to get into midline better for bilateral amputee | More training required Heavier in weight Harnessing more complicated Elbow needs to be locked to operate TD |
| Myoelectric or switch-activated elbow | Electric elbow that can be operated by either an electrode or physical switch | Can be used with children over 36–48 months | Less taxing to operate than BP Can be used with electric or body powered TD | Cost Heavy High maintenance Need to charge batteries |
| Activity-specific prosthesis | Sports specific Musical instrument specific adaptation | Can be used at any age as appropriate activities are identified Adapters are available for a multitude of activities including ski pole, bike, golf club, weight lifting, violin, guitar, fishing rod, and hockey stick | Allows for bimanual function for specific sports or activities that otherwise would be difficult or impossible Can sometimes be interchanged in same socket as TD with a quick disconnect wrist unit | Additional cost that may not be covered by insurance |
| Multigrasp hand such as iLimb ( Image 6.2 ) or Bebionic | One of the most advanced myoelectric prosthetics looks and moves more like a natural hand | More available to adult-sized adolescent Recently, iLimb developed an extra small size that may be used with some preadolescent patients | Conforming grip Multiple grip patterns Natural more fluid hand movements | Cost Heavy High maintenance Better for light load work |
| Pattern recognition | Myoelectric control system that uses multiple sites (up to 8) control and algorithms to control prosthesis | Only available to adult-sized adolescent | Allows user to use more natural multi muscle patterns for activation Allows for more functions with same number of muscles User can recalibrate as needed | May be difficult for nontechnology savvy user/family Training more difficult |
| iDigit | An advanced myoelectric prosthesis for partial hand amputees | Sizing tends to be a limitation as in the case of the iLimb | Conforming grasp Multiple grasp patterns Light-to-moderate work load | Cost Lack of sensory feedback Batteries need to be charged May be difficult for nontechnology savvy user/family |
| 3D printed partial hand prosthesis | Prosthetic that operates off wrist motion much like a tenodesis splint | Best for child with metacarpals intact | Low cost Good for task-specific activities | May not hold up to wear and tear of child |
Rehabilitation for Upper Limb Prosthetic Patients
Rehabilitation will be discussed separately as appropriate for acquired or traumatic amputations versus congenital deficiencies. The main difference is the preprosthetic stage due to the preparation and care needed before prosthetics can be initiated. Later stages should not vary significantly between the two groups. In either acquired or congenital situations, parent and child education as well as more frequent follow-up are critical to encourage long-term use and success. The importance of a cohesive, experienced clinic team with the ability to follow the child with an amputation cannot be underestimated in importance. Education with respect to available choices including no prosthesis, emotional support, and opportunities for peer support, and consistent follow-up have all been reported to be helpful and valued by patients with limb differences and their families.
Prosthetic needs change throughout childhood, and as the needs of the child change and multiply prosthetic intervention may need to be modified. Rehabilitation may be required at different ages and stages. Intensity of rehabilitation is often variable depending on the situation. Early fitting has been debated but is advocated by most clinical teams if the family is interested. Most studies have found that fitting before 2 years old is preferable for congenital amputees and within 6 months postinjury for acquired amputations. The standard of care for traumatic amputees without complication in adults is fitting with a temporary prosthesis within 30 days. In pediatrics, there may be multiple complications that do not allow this to happen. Funding for prosthetics is more difficult and is often a major complication and reason for time delay. Despite this, there are creative ways to try and establish an early understanding and pattern of prosthetic use for the young traumatic amputee. Image 6.4 is a picture of a thermoplastic splint that was fabricated to give a young amputee play-specific function and the experience of wearing a full contact pseudo socket.
