Use of the Ipsilateral Scapular Cutaneous Anchor in Children with Unilateral Below Elbow Deficiency
Traditionally, a body-powered prosthesis is activated by a figure-of-eight or a figure-of-nine harness system, using the contra-lateral shoulder as the power source. Many users of this system complain of discomfort from the harness rubbing on the skin especially in the axilla and at the O-ring, asymmetry of the shoulders, pain in the contra-lateral shoulder area, difficulty while performing bilateral tasks, and diminished cosmesis. Occupational therapists such as me help clients develop skills to live as independently as possible and to improve the quality of their lives. I have invented a new way of harnessing a body-powered prosthesis that will potentially help patients to achieve these goals. This design eliminates the harnessing which is often a source of complaint and one reason why children reject prostheses.
In using this device as part of treatment of children with an upper limb deficiency, several questions arise. When used in conjunction with a body-powered below elbow prosthesis, will this device:
- impact frequency of use of the body-powered prosthesis?
- facilitate improved function of the body-powered prosthesis?
- facilitate improvement in strength of the ipsilateral shoulder?
- reduce pain and/or discomfort likely to occur in the contralateral shoulder of individuals that are using a body-powered prosthesis?
- impact perceived self-esteem among users of a body-powered prosthesis?
The anticipated outcomes of this retrospective study are to determine if the use of the Ipsilateral Scapular Cutaneous Anchor have impacted these areas. A review of literature reveals six themes:
- etiology and statistics of the population with unilateral (congenital) below elbow deficiency [UCBED];
- prosthetic design;
- prosthetic training;
- tests of prosthetic function;
- social issues; and
- consumers as contributors to design
Atkins et al (2003) conducted a survey in which 2,477 individuals with U-BED responded. Statistics of this group include the following data:
- 63% were male, 37% were female;
- 47% were age 17 years or younger;
- 57% were trans-radial;
- 91% were congenital.
This data correlates with investigators from other countries including Great Britain, Australia, Denmark and India who note that among children, congenital anomalies are the most common reason for limb deficiency, males outnumber females by a 2:1 ratio, and of the upper limb deficiencies, trans-radial appears to be the most common.
LeBlanc noted in 1985 that the standard body-powered prosthetic design has not changed since the 1950's. As I view my first prosthesis from the mid-1950's I find this to be profoundly true even today in 2007. Fifty years have passed and the basic design, including the harnessing remains a constant. LeBlanc was part of two teams that attempted alternative designs to 'harness' body power in the triceps Power Capture (1989) and the Axilla Bypass Ring (1996). It was also Collier and LeBlanc who noted in 1996 that the harness may cause numbness, nerve damage and may correlate to a 50% rejection rate of the prosthesis.
Prosthetic training is based upon normal growth and developmental guidelines. Specific developmental milestones (such as sitting) and even tasks (such as shoe-tying) are used as key indicators of prosthetic readiness (Clarke, 1991). Krebs et al (1991) reported that providers should be familiar with available technology, and relate the qualities of the prosthesis with the needs and desires of the child as an individual and as part of a family group. [Image ]
Multiple studies have utilized different measures of prosthetic function. These may include the University of New Brunswick Test (UNB), the Unilateral Below Elbow Test (U-BET), the Prosthetic Satisfaction Inventory (PSI) and the Prosthetic Use Function Inventory (PUFI).
Our hands and their function reflect an important posture in contemporary society and prosthetic use may present social issues. We use our hands in social rituals such as in a handshake, praying, dancing, and embracing others or simply in holding hands. Individuals using upper extremity prosthesis often avoid touching others with the prosthesis. Hand function facilitates our ability to identify our selfconcept of competency in both basic and instrumental activities of daily living. It is important that none of this is lost in an individual with an upper limb deficiency. Many upper extremity prosthetic users report pain, discomfort, lack of cosmesis and selfconsciousness (Postema, 1999).
Atkins et al reported in 2003 that research and development of upper extremity prostheses were not consumer-driven. Ten years prior, Kejlaa (1993) cited multiple consumer concerns with the design and function of the body-powered prosthesis. Both Shaperman et al (1995) and Meeks & LeBlanc (1996) noted that the harness was cited most commonly as the least liked aspect of the prosthesis and the feature most in need of change. Crandall & Tomhave reported that users choose the type of prosthesis based on function and that most function is attained through simplistic design. Consumer contributions to design of the unilateral below elbow prostheses might produce a more user-friendly device.
The Ipsilateral Scapular Cutaneous Anchor (the "Anchor") system derives its primary source of control from the ipsilateral scapula. The "Anchor" requires a tighter fitting socket due to the elimination of the suspension support from the harness. The cable is attached to a plastic patch in the center of which is a metal button. The patch is adhered to the skin in the area of the scapula. The terminal device is then operated by abducting and/or protracting the shoulder on the same side as the residual short limb. Because the harness is eliminated, the benefits of this system include increased comfort, improved cosmesis and decreased impingement at the axilla. Other benefits include more symmetrical bilateral muscle development, decreased repetitive motion in the contra-lateral shoulder and increased function particularly during bilateral upper extremity tasks. A patent has been filed by Shriners Hospital for Children and they are currently researching marketing opportunities for the device.
The Anchor system has been used in patient treatment for the past 20 months at Shriners Hospital for Children-Springfield. To date, 24 individuals; ages 6-20 years who present with unilateral trans-radial deficiency and were active users of a body-powered prosthesis, with either a voluntary opening or voluntary closing terminal device have chosen to try the Anchor.
The scapular anchor system attached to the ipsilateral side. Each patient was provided with 2 patches, rolls of double-sided skin-friendly tape, athletic pre-tape spray, alcohol pads and tincture of benzoin.
Each patient is evaluated in a multi-disciplinary clinic. A screening tool and interview are used to identify suitable candidates, and then the prosthetist fabricates a new tighter fitting forearm socket. The prosthetist and occupational therapist fit the patient with the ‘Anchor'. Prosthetic training is provided which includes application, use and care of the ‘Anchor'. Baseline testing is completed which includes the U-BET and PSI as well as clinical observations using both the traditionally-harnessed prosthesis and the new prosthesis. The patient uses the device at home for three months and then is re-tested using the same tools. Re-evaluations have continued on a quarterly basis. [Image ]
Data is available in patient charts through documentation from patient visits for evaluation and treatment. Such data is expected to include results of functional-abilities and quality of life measures such as the patient- and parent-completed PSI, the U-BET, and clinical notes and films.
Initial observations have been reported to include ease in application, continued success with prosthetic use, increased use, improved cosmesis and patient satisfaction. A full review of patient charts will help to substantiate these assertions.
The Shriners Anchor is simple in design and the parts are durable, easily available and affordable. The potential benefits of this system may result in increased prosthetic wear and use as they allow for improved comfort, cosmesis and ease of use during functional activity, particularly bilateral tasks. It is thought that use of the ‘Anchor' at an early age might prevent previouslydescribed complications in the unaffected extremity and serve to improve symmetry in the shoulder girdle of the involved side. Implications for use include the possibility of a hybrid-type of power system for individuals with trans-humeral deficiency. This device might also be utilized to ‘dynamize' an elbow; wrist or hand orthosis to increase function among individuals with spinal cord, brachial plexus or hemiplegic involvement. Future studies will include members of these populations. Certainly this system is not limited to use in pediatric patients but will well-serve the adult population as well.
This system appears to enable pediatric patients with upper limb deficiency to achieve greater levels of functional independence and improved quality of life.
Partial List of References
- Crandall, R.C. and Tomhave, W. J Pedi Orthop 22 (3):380-3.
- Datta, D. and Ibbotson, V. Prosthet Orthot Int 22 (2):150-4.
- Kejlaa, G.H. Prothet Orthot Int 17 (3): 157-63.
- Murray, C. Journal of Health Psychology 10 (3):425-441.
- Postema, K. et al, Clin Rehab 13 (3): 243-24
Debra Latour, M.Ed.,OTR/L Shriners Hospital for Children, Springfield, MA