Shoulder Disarticulation-Type Prostheses For Bilateral Upper Extremity Amputees

Mllo B. Brooks, M.D. Jeannlne F. Dennis, O.T.R.

Bilateral upper extremity amputees whose deficiencies require fitting with some type of shoulder disarticulation prosthesis can be classified in three major categories. The first group includes the bilateral shoulder disarticulation amputees: these patients may have a normal axial skeleton and a relatively normal shoulder girdle, or there may be anomalies of the axial and/or appendicular skeletal structures. When such skeletal anomalies are present (e.g., scoliosis, small clavicles and scapulae), the problems of prosthesis fitting, training, and acceptance are increased considerably.

The second category includes those patients with bilateral upper extremity phocomelias, with either single or multiple digits. This group is perhaps the most challenging to the prosthetist and therapist.

In the third group are those patients with short above-elbow stumps which are too weak or anomalous to be fitted with short above-elbow prostheses.

Although certain problems of fitting, training, and acceptance are common to all three groups, each category poses unique problems for the clinic team. To some of these problems, fairly satisfactory solutions (within the limits of our present knowledge and skill) have been found; others still offer stubborn resistance to the most determined research efforts.

Pre-Prosthetic Considerations

In every case of a child who will eventually be fitted with shoulder disarticulation prostheses, early and careful planning is of great importance.

Pre-prosthetic corrective surgery may be indicated; if so, the orthopedist may find it helpful to confer with the prosthetist before a decision for surgery is made: finger nubbins or other vestigial appendages which are cosmetically unsatisfactory and apparently useless may provide the prosthetist with a means for activating an elbow lock or other mechanism. Fig. 1 and Fig. 2 illustrate the case of one phocomelic patient who makes good use of a single-digit right appendage to operate an elbow lock. (She is fitted on the left with an apposition post.) Among the CAPP patients in the three groups cited, orthopedic surgery has rarely been indicated, although in one or two phocomelic cases we have removed exostoses that interfered with prosthesis fitting.

The parents of the infant bilateral shoulder disarticulation amputee have an important role in the careful pre-prosthetic preparation so essential for these patients. The infant must be encouraged and assisted in his natural desire to be active, and a young baby without arms is unable to lift his head to observe the world around him; the mother will need to place him in the prone position with a pillow under his chest and abdomen, thus freeing his face and allowing him to engage in head activity that will help to build up his neck extensors while he satisfies his natural interest in his environment.

The mother should be made aware of the assistance necessary to help the child through the various levels of his neuromuscular development: head balance, rolling, sitting, and eventual standing balance and walking. For example, the mother can help the baby to roll over by initiating the motion. The infant will need assistance and support in learning to sit. It is also important for the mother to know that it is essential to withdraw this support when the child no longer requires it.

When the baby indicates a readiness to stand, the mother becomes the arm substitute (as illustrated in Fig. 3 ). The parent may not realize the need to put the child in a standing position when he displays readiness, and to provide him with secure support. The child without upper extremities needs a great deal of practice in this position, even before he is actually ready to walk. All children at this developmental level love jumping and kicking activities in an upright, supported position, and these give essential exercise to the legs and trunk. Even a normal child does not suddenly attain the sitting or standing position, and these preliminary activities are prerequisites to unsupported standing balance and eventual walking.

It has been observed that bilateral shoulder disarticulation amputees are late walkers (for example, the child in Fig. 7 walked at twenty-five months). Their lack of balance due to the absence of arms is certainly one of the reasons for this; the instinctive fear of falling and hurting themselves is probably intensified by this lack of balance, and it is imperative that they be provided not only with proper positioning and support in the early stages of ambulation, but also that they be protected when they do fall, and, later, taught how to get up from the floor. Parents also need instruction and assistance in accident prevention; the use of a bicycle helmet is most helpful in providing protection for the child's head, and tumbling and rolling can be good activities for promoting skill in self-protection.

Use of the Feet

Lacking upper extremities, even the very young child will make use of his feet for many activities, and will probably become remarkably skillful in their use and very dependent upon them. It is rather difficult to determine just which uses of the feet should be encouraged: the bilateral amputee with severe upper extremity involvements needs pedal skill for activities that he may find difficult or impossible to accomplish with prostheses (for example, some bilateral upper extremity amputees make use of their feet to preposition their prosthetic devices). However, it must be remembered that the child will need to learn and perfect certain skills with his prostheses to develop more socially acceptable adult habits: chief among these is eating; and the child who has learned to feed himself with his feet is usually very reluctant to abandon this method for the slow and initially relatively unsatisfactory prosthetic techniques. Therefore it appears that this is one use of the feet which should be discouraged if not forbidden entirely.

An example of the value of this recommendation is illustrated by the case of the bilateral shoulder disarticulation amputee in Fig. 5 : this little girl was never permitted to eat with her feet, although she was encouraged to make use of them in many other activities, such as dressing her dolls - at which she is very skillful. Even though she was not fitted with upper extremity prostheses until the age of two years and nine months, the parents had planned on prosthesis fitting from the time she was bom; they learned what was available, and their whole treatment of the child was a preparation for a prosthetics program. When the child did receive her prostheses, she had no prior eating habits to unlearn, and she very quickly and enthusiastically accepted training in self-feeding with her prostheses.

These children need the best possible physical development in order to be capable of even reasonably successful prosthesis use, and CAPF studies of patient performance and acceptance indicate that the best users are those children with superior body agility. This agility, plus the acquisition of a few "tricks" of prosthesis use, sometimes will make the difference between success and failure in prosthetic function for these patients.

The Prosthesis Prescription

It has been the experience of the CAPP staff that phocomelia patients do not accept prostheses as readily as children with either congenital or acquired amputations. The reason for this is not yet clear. It has also been observed that prosthesis rejection is more common among phocomelia patients whose anomalous limbs have multiple rather than single digits.

In the phocomelia cases, the presence of the vestigial limbs complicates the design problem, and the prosthesis prescription must be based partially on functional evaluations of the child's performance without prosthesis as compared to the anticipated performance with prosthetic devices. The clinic team must determine the child's functional capabilities without prosthesis, and this evaluation must be continued after the prosthesis has been fitted, for it is possible that the prosthetic device may prohibit manipulative ability, tactile sensation, and a sense of freedom more necessary to the child than the improved grasp and additional reach which the prosthesis provides.

One of the principal problems in fitting the patients in all three of the categories is the lack of power available to operate the prosthesis or prostheses. This is true of patients with bilateral short above-elbow amputations or phocomelias as well as the shoulder disarticulation amputees. It often requires all the skill and ingenuity the prosthetist can command to provide the child with even minimal function, and each individual case requires a detailed evaluation by the clinic team.

In the case of one bilateral shoulder disarticulation amputee with an additional lower extremity deficiency, this problem of insufficient power was solved by attaching the control straps to the child's lower extremity prosthesis (Fig. 4 , Fig. 5 , and Fig. 6 ). The use of the lower extremity prosthesis as an anchoring point provided the child with sufficient power for good function with her upper extremity prostheses (Fig. 5 ).

The success of this design led to its modification for use on bilateral upper extremity amputees who had normal lower extremities, in which a thigh-cuff of laminated plastic served as the anchoring point for the upper extremity harness system (Fig. 9 and Fig. 10 ). This thigh-cuff is shaped in the same manner as a quadrilateral above-knee socket. The initial contact point is placed on the ischial tuberosity with reaction on the lateral side close to the greater trochanter, thereby avoiding the perineal pressure that is such a disadvantage of the perineal strap harness. This design has permitted separation of controls in bilateral upper extremity amputees; it also appears to greatly reduce the effort required to operate the controls, and to give the child a greater range of motion. When scapular abduction will not provide the desired amount or range of power, shoulder elevation plus trunk bending can be utilized with this design.

The boy in Fig. 7 , Fig. 8 , Fig. 9 , and Fig. 10 has a congenital left shoulder disarticulation and a right standard above-elbow amputation, also congenital. The above-elbow stump has a subluxed humerus and is very weak. The shoulder structure is normal. He was fitted initially on the short above-elbow side, with a weighted shoulder cap on the left. At the age of twenty-two months, a shoulder disarticulation-type prosthesis without active controls replaced the weighted shoulder cap, and the right prosthesis was provided with a single active control to the hook (see Fig. 8 ). With this he had very minimal operation at three years of age. There was no appreciable improvement in his performance until, at the age of four years and five months, he was fitted with the bilateral prostheses illustrated in Fig. 9 and Fig. 10 , utilizing the thigh-cuff design. The result was immediate operation of bilateral dual control systems, and a functional amount of hook loading on both sides was possible for the first time.

The child in Fig. 11 and Fig. 12 , a quadrilateral amputee with bilateral shoulder disarticulations and bilateral lower extremity phocomelias, was first provided with a pelvic bucket to assist her in attaining a stable sitting position. When she was fitted with bilateral upper extremity prostheses, the harness straps were anchored with snap fasteners to the pelvic bucket, which served as the anchor point. She was fitted with single (because of age and immaturity) active controls on both sides, and demonstrates excellent function with these.

The Training Program

In working with the infant bilateral upper extremity amputee, the therapist will find it necessary to introduce the child to the concept of arms and their function as instruments of balance and grasp in a sitting and later a standing world. The use of the prostheses for gross activities, such as those illustrated in Fig. 13 and Fig. 14 , afford excellent opportunities to familiarize the child with these concepts. At the same time, foot skill must be maintained and body agility developed, In fact, the most successful prosthesis function appears to result from a combination of skillful prosthesis, body, and foot activity. However, the emphasis should always be on the development of long-term habits and skills.

Prosthesis Acceptance Among These Patients

Among eighteen cases which were studied at CAPP, eight were bilateral shoulder disarticulations, seven were bilateral phocomelias (five of these had multiple digits, and two had single digits), one had a shoulder disarticulation plus a phocomelia with a single digit, and the other two had a shoulder disarticulation plus an above-elbow amputation.

There were three cases of chronic non-acceptance among these patients: one of these was a bilateral shoulder disarticulation, another a bilateral phocomelia with multiple digits, and the third a unilateral shoulder disarticulation plus a phocomelia with a single digit. Two of these patients had a history of parental non-support; the third, an adolescent girl, refuses to use her functional prostheses, but will occasionally wear prostheses fitted with cosmetic hands.

One bilateral shoulder disarticulation has demonstrated poor acceptance. However, this particular case is complicated by a severe scoliosis and kyphosis, a fused spine, plus an additional lower extremity deformity, and the child is able to obtain very little function. A new prosthesis, similar to the one illustrated in Fig. 6 , has been prescribed for this child, and it is anticipated that this will result in some improvement in function. The remainder of the cases in all three groups demonstrated prosthesis acceptance and function that ranged from good to excellent.

It appears that, unless there are other disruptive influences (such as parental non-support) present, acceptance generally follows training with an appropriate, properly designed and well-functioning prosthesis.

Child Amputee Prosthetics Project, University of California at Los Angeles